Add Spreadtrum Sharkl64 Platform support

The file of-serial.txt was only for 8250 compatible UART implementations, so renamed it to 8250.txt to avoid confusing other persons. This is suggested by Arnd, see:
http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/291455.html

Signed-off-by Chunyan Zhang <[email protected]>

Acked-by Mark Rutland <[email protected]>

---
 .../bindings/serial/{of-serial.txt => 8250.txt}    |    0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename Documentation/devicetree/bindings/serial/{of-serial.txt => 8250.txt} (100%)

Documentation/devicetree/bindings/serial/8250.txt renamed from Documentation/devicetree/bindings/serial/of-serial.txt +0 -1

similarity index 100%
rename from Documentation/devicetree/bindings/serial/of-serial.txt
rename to Documentation/devicetree/bindings/serial/8250.txt
--

1.7.9.5

_______________________________________________
linux-arm-kernel mailing list linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Adds Spreadtrum's prefix "sprd" to vendor-prefixes file. Adds the devicetree binding documentations for Spreadtrum's sc9836-uart and SC9836 SoC based on the Sharkl64 Platform which is a 64-bit SoC Platform of Spreadtrum.

Signed-off-by Chunyan Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

---
 Documentation/devicetree/bindings/arm/sprd.txt     |   11 +++++++++++
 .../devicetree/bindings/serial/sprd-uart.txt       |    7 +++++++
 .../devicetree/bindings/vendor-prefixes.txt        |    1 +
 3 files changed, 19 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/sprd.txt
 create mode 100644 Documentation/devicetree/bindings/serial/sprd-uart.txt

Documentation/devicetree/bindings/arm/sprd.txt new file +11 -0

new file mode 100644
index 0000000..31a629d
@@ -0,0 +1,11 @@
+Spreadtrum SoC Platforms Device Tree Bindings
+----------------------------------------------------
+
+Sharkl64 is a Spreadtrum's SoC Platform which is based
+on ARM 64-bit processor.
+
+SC9836 openphone board with SC9836 SoC based on the
+Sharkl64 Platform shall have the following properties.
+
+Required root node properties:
+        - compatible = "sprd,sc9836-openphone", "sprd,sc9836";

Documentation/devicetree/bindings/serial/sprd-uart.txt new file +0 -0

new file mode 100644
index 0000000..2aff0f2

Documentation/devicetree/bindings/vendor-prefixes.txt +1 -0

index b1df0ad..0a8384f 100644
@@ -153,6 +153,7 @@ snps	Synopsys, Inc.
 solidrun	SolidRun
 sony	Sony Corporation
 spansion	Spansion Inc.
+sprd	Spreadtrum Communications Inc.
 st	STMicroelectronics
 ste	ST-Ericsson
 stericsson	ST-Ericsson

Signature · 1 line

1.7.9.5

Documentation/devicetree/bindings/serial/sprd-uart.txt line 7

Quoted 6 lines

Documentation/devicetree/bindings/serial/sprd-uart.txt new file +6 -0

+
+Required properties:
+- compatible: must be "sprd,sc9836-uart"
+- reg: offset and length of the register set for the device
+- interrupts: exactly one interrupt specifier
+- clocks: phandles to input clocks.

The order and relevance of each should be specified. If you have multiple clocks I would strongly recommend you use clock-names to distinguish them.

Otherwise this looks fine.

Mark.

Hi, Mark

Quoted 11 lines

Documentation/devicetree/bindings/serial/sprd-uart.txt line 7

Quoted 6 lines

Documentation/devicetree/bindings/serial/sprd-uart.txt new file +6 -0

+
+Required properties:
+- compatible: must be "sprd,sc9836-uart"
+- reg: offset and length of the register set for the device
+- interrupts: exactly one interrupt specifier
+- clocks: phandles to input clocks.

The order and relevance of each should be specified. If you have multiple clocks I would strongly recommend you use clock-names to distinguish them.

Thank you for the recommendation.
but, since we haven't made the clock driver ready, for this initial commit, we just let 4 UARTs share a single fixed 26 MHz clock source. we'll do like you've recommended when we will submit the clock driver in the future.

Quoted 14 lines · Lyra Zhang

Hi, Mark

Quoted 11 lines

Documentation/devicetree/bindings/serial/sprd-uart.txt line 7

Quoted 6 lines

Documentation/devicetree/bindings/serial/sprd-uart.txt new file +6 -0

+
+Required properties:
+- compatible: must be "sprd,sc9836-uart"
+- reg: offset and length of the register set for the device
+- interrupts: exactly one interrupt specifier
+- clocks: phandles to input clocks.

The order and relevance of each should be specified. If you have multiple clocks I would strongly recommend you use clock-names to distinguish them.

Quoted 5 lines

Thank you for the recommendation.
but, since we haven't made the clock driver ready, for this initial commit, we just let 4 UARTs share a single fixed 26 MHz clock source. we'll do like you've recommended when we will submit the clock driver in the future.

I'm on about the clock input lines on the UART instance, not the providers they come from.

Is there only a single clock input line on each UART? Perhaps multiple input lines which are currently fed by the same clock?

Thanks,
Mark.

From: Zhizhou Zhang <[email protected]>

Adds the device tree support for Spreadtrum SC9836 SoC which is based on Sharkl64 platform.

Sharkl64 platform contains the common nodes of Spreadtrum's arm64-based SoCs.

Signed-off-by Zhizhou Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Signed-off-by Chunyan Zhang <[email protected]>

---
 arch/arm64/boot/dts/Makefile                  |    1 +
 arch/arm64/boot/dts/sprd/Makefile             |    5 ++
 arch/arm64/boot/dts/sprd/sc9836-openphone.dts |   49 +++++++++++++++++
 arch/arm64/boot/dts/sprd/sc9836.dtsi          |   73 +++++++++++++++++++++++++
 arch/arm64/boot/dts/sprd/sharkl64.dtsi        |   67 +++++++++++++++++++++++
 5 files changed, 195 insertions(+)
 create mode 100644 arch/arm64/boot/dts/sprd/Makefile
 create mode 100644 arch/arm64/boot/dts/sprd/sc9836-openphone.dts
 create mode 100644 arch/arm64/boot/dts/sprd/sc9836.dtsi
 create mode 100644 arch/arm64/boot/dts/sprd/sharkl64.dtsi

arch/arm64/boot/dts/sprd/sc9836.dtsi new file +22 -0

+	cpus {
+		#address-cells = <2>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a53", "arm,armv8";
+			reg = <0x0 0x0>;
+			enable-method = "psci";
+		};
+
+		cpu@1 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a53", "arm,armv8";
+			reg = <0x0 0x1>;
+			enable-method = "psci";
+		};
+
+		cpu@2 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a53", "arm,armv8";
+			reg = <0x0 0x2>;

arch/arm64/boot/dts/sprd/sharkl64.dtsi new file +6 -0

new file mode 100644
index 0000000..b08989d
@@ -0,0 +1,67 @@
+/*
+ * Spreadtrum Sharkl64 platform DTS file
+ *
+ * Copyright (C) 2014, Spreadtrum Communications Inc.
+ *
+ * This file is licensed under a dual GPLv2 or X11 license.

Quoted 21 lines · Chunyan Zhang

From: Zhizhou Zhang <[email protected]>

Adds the device tree support for Spreadtrum SC9836 SoC which is based on Sharkl64 platform.

Sharkl64 platform contains the common nodes of Spreadtrum's arm64-based SoCs.

Signed-off-by Zhizhou Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Signed-off-by Chunyan Zhang <[email protected]>

---
 arch/arm64/boot/dts/Makefile                  |    1 +
 arch/arm64/boot/dts/sprd/Makefile             |    5 ++
 arch/arm64/boot/dts/sprd/sc9836-openphone.dts |   49 +++++++++++++++++
 arch/arm64/boot/dts/sprd/sc9836.dtsi          |   73 +++++++++++++++++++++++++
 arch/arm64/boot/dts/sprd/sharkl64.dtsi        |   67 +++++++++++++++++++++++
 5 files changed, 195 insertions(+)
 create mode 100644 arch/arm64/boot/dts/sprd/Makefile
 create mode 100644 arch/arm64/boot/dts/sprd/sc9836-openphone.dts
 create mode 100644 arch/arm64/boot/dts/sprd/sc9836.dtsi
 create mode 100644 arch/arm64/boot/dts/sprd/sharkl64.dtsi

[...]

Quoted 26 lines

arch/arm64/boot/dts/sprd/sc9836.dtsi new file +26 -0

+     cpus {
+             #address-cells = <2>;
+             #size-cells = <0>;
+
+             cpu at 0 {
+                     device_type = "cpu";
+                     compatible = "arm,cortex-a53", "arm,armv8";
+                     reg = <0x0 0x0>;
+                     enable-method = "psci";
+             };
+
+             cpu at 1 {
+                     device_type = "cpu";
+                     compatible = "arm,cortex-a53", "arm,armv8";
+                     reg = <0x0 0x1>;
+                     enable-method = "psci";
+             };
+
+             cpu at 2 {
+                     device_type = "cpu";
+                     compatible = "arm,cortex-a53", "arm,armv8";
+                     reg = <0x0 0x2>;
+                     enable-method = "psci";
+             };
+
+             cpu at 3 {

arch/arm64/boot/dts/sprd/sc9836.dtsi line 46

Quoted 6 lines

arch/arm64/boot/dts/sprd/sc9836.dtsi new file +6 -0

+                     device_type = "cpu";
+                     compatible = "arm,cortex-a53", "arm,armv8";
+                     reg = <0x0 0x3>;
+                     enable-method = "psci";
+             };
+     };

Just to check, all CPUs may be hotplugged off and on, yes?

Including CPU0?

How is your implementation tested?

You boot CPUs at EL2?

arch/arm64/boot/dts/sprd/sc9836.dtsi line 56

Quoted 10 lines

arch/arm64/boot/dts/sprd/sc9836.dtsi new file +10 -0

+
+     gic: interrupt-controller at 12001000 {
+             compatible = "arm,gic-400";
+             #interrupt-cells = <3>;
+             interrupt-controller;
+             reg = <0 0x12001000 0 0x1000>,
+                   <0 0x12002000 0 0x2000>,
+                   <0 0x12004000 0 0x2000>,
+                   <0 0x12006000 0 0x2000>;
+     };

You're missing the maintenance interrupt here.

[...]

Quoted 16 lines

arch/arm64/boot/dts/sprd/sharkl64.dtsi new file +10 -0

new file mode 100644
index 0000000..b08989d
@@ -0,0 +1,67 @@
+/*
+ * Spreadtrum Sharkl64 platform DTS file
+ *
+ * Copyright (C) 2014, Spreadtrum Communications Inc.
+ *
+ * This file is licensed under a dual GPLv2 or X11 license.
+ */
+
+/ {
+     interrupt-parent = <&gic>;

arch/arm64/boot/dts/sprd/sharkl64.dtsi line 16

Quoted 6 lines

arch/arm64/boot/dts/sprd/sharkl64.dtsi new file +6 -0

+     #address-cells = <2>;
+     #size-cells = <2>;
+
+     soc {
+             compatible = "simple-bus";
+             reg = <0x0 0x0 0x0 0x80000000>;

What is this reg for? It's not required by simple-bus.

If you want to encode that this covers a particular portion of the address space, do so with the ranges proeprty.

arch/arm64/boot/dts/sprd/sharkl64.dtsi line 23

Quoted 8 lines

arch/arm64/boot/dts/sprd/sharkl64.dtsi new file +7 -0

+             #address-cells = <2>;
+             #size-cells = <2>;
+             ranges;
+
+             ap_apb: apb at 70000000 {
+                     compatible = "simple-bus";
+                     reg = <0x0 0x70000000 0x0 0x10000000>;

Likewise here.

Thanks,
Mark.

Hi, Mark,

Quoted 51 lines · Mark Rutland

Quoted 21 lines · Chunyan Zhang

From: Zhizhou Zhang <[email protected]>

Adds the device tree support for Spreadtrum SC9836 SoC which is based on Sharkl64 platform.

Sharkl64 platform contains the common nodes of Spreadtrum's arm64-based SoCs.

Signed-off-by Zhizhou Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Signed-off-by Chunyan Zhang <[email protected]>

---
 arch/arm64/boot/dts/Makefile                  |    1 +
 arch/arm64/boot/dts/sprd/Makefile             |    5 ++
 arch/arm64/boot/dts/sprd/sc9836-openphone.dts |   49 +++++++++++++++++
 arch/arm64/boot/dts/sprd/sc9836.dtsi          |   73 +++++++++++++++++++++++++
 arch/arm64/boot/dts/sprd/sharkl64.dtsi        |   67 +++++++++++++++++++++++
 5 files changed, 195 insertions(+)
 create mode 100644 arch/arm64/boot/dts/sprd/Makefile
 create mode 100644 arch/arm64/boot/dts/sprd/sc9836-openphone.dts
 create mode 100644 arch/arm64/boot/dts/sprd/sc9836.dtsi
 create mode 100644 arch/arm64/boot/dts/sprd/sharkl64.dtsi

[...]

Quoted 26 lines

arch/arm64/boot/dts/sprd/sc9836.dtsi new file +26 -0

+     cpus {
+             #address-cells = <2>;
+             #size-cells = <0>;
+
+             cpu at 0 {
+                     device_type = "cpu";
+                     compatible = "arm,cortex-a53", "arm,armv8";
+                     reg = <0x0 0x0>;
+                     enable-method = "psci";
+             };
+
+             cpu at 1 {
+                     device_type = "cpu";
+                     compatible = "arm,cortex-a53", "arm,armv8";
+                     reg = <0x0 0x1>;
+                     enable-method = "psci";
+             };
+
+             cpu at 2 {
+                     device_type = "cpu";
+                     compatible = "arm,cortex-a53", "arm,armv8";
+                     reg = <0x0 0x2>;
+                     enable-method = "psci";
+             };
+
+             cpu at 3 {

Quoted 9 lines

arch/arm64/boot/dts/sprd/sc9836.dtsi line 46

Quoted 6 lines

arch/arm64/boot/dts/sprd/sc9836.dtsi new file +6 -0

+                     device_type = "cpu";
+                     compatible = "arm,cortex-a53", "arm,armv8";
+                     reg = <0x0 0x3>;
+                     enable-method = "psci";
+             };
+     };

Just to check, all CPUs may be hotplugged off and on, yes?

Yes, I have tested with them successfully by looking into /proc/interrupts and top except CPU0.

Quoted 2 lines

Including CPU0?

It returns "status busy" after I type the command below.

Quoted 2 lines

How is your implementation tested?

I build kernel image with 3.19-rc1 + this patchset and run into console. I use echo 0 > /sys/devices/system/cpu[0-3]/online

BTW, I run these on a real phone of sc9836 not fast-model as before.

Quoted 2 lines

You boot CPUs at EL2?

Yes, I have confirmed this when working around the BUG() in arch_counter_get_cntpct() introduced from 3.19.

Quoted 12 lines

Quoted 11 lines

arch/arm64/boot/dts/sprd/sc9836.dtsi new file +10 -0

+
+     gic: interrupt-controller at 12001000 {
+             compatible = "arm,gic-400";
+             #interrupt-cells = <3>;
+             interrupt-controller;
+             reg = <0 0x12001000 0 0x1000>,
+                   <0 0x12002000 0 0x2000>,
+                   <0 0x12004000 0 0x2000>,
+                   <0 0x12006000 0 0x2000>;
+     };

Quoted 2 lines

You're missing the maintenance interrupt here.

Do you mean to declare SGI like this ?

" interrupts = <1 9 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)> "

Quoted 19 lines

[...]

Quoted 16 lines

arch/arm64/boot/dts/sprd/sharkl64.dtsi new file +10 -0

new file mode 100644
index 0000000..b08989d
@@ -0,0 +1,67 @@
+/*
+ * Spreadtrum Sharkl64 platform DTS file
+ *
+ * Copyright (C) 2014, Spreadtrum Communications Inc.
+ *
+ * This file is licensed under a dual GPLv2 or X11 license.
+ */
+
+/ {
+     interrupt-parent = <&gic>;

Quoted 9 lines

arch/arm64/boot/dts/sprd/sharkl64.dtsi line 16

Quoted 6 lines

arch/arm64/boot/dts/sprd/sharkl64.dtsi new file +6 -0

+     #address-cells = <2>;
+     #size-cells = <2>;
+
+     soc {
+             compatible = "simple-bus";
+             reg = <0x0 0x0 0x0 0x80000000>;

What is this reg for? It's not required by simple-bus.

It's added by me.
I want to tell people the register range of what the bus covers, not for any drivers use.

for this example, It starts from address 0 to 0x80000000.
Because Spreadtrum chip is very large with a lots of registers and matrix buses.

Quoted 3 lines

If you want to encode that this covers a particular portion of the address space, do so with the ranges proeprty.

But I look up the ePAPER who says "The ranges property provides a means of defining a mapping or translation...".
The bus here is flat-memory for all.

Quoted 9 lines

arch/arm64/boot/dts/sprd/sharkl64.dtsi line 23

Quoted 9 lines

arch/arm64/boot/dts/sprd/sharkl64.dtsi new file +7 -0

+             #address-cells = <2>;
+             #size-cells = <2>;
+             ranges;
+
+             ap_apb: apb at 70000000 {
+                     compatible = "simple-bus";
+                     reg = <0x0 0x70000000 0x0 0x10000000>;

Quoted 3 lines

Likewise here.

This initial patch is picked up from a very big dt file. There are several apb buses in this chip.

So I use apb at starting-address to separate them.
But I remember another rule that the @address needs to equal first address in property reg array.
Do I have to delete @7000000 as well if i delete reg line?

Quoted 3 lines · Orson Zhai

Hi, Mark,

On Fri, Jan 16, 2015 at 6:35 PM, Mark Rutland <[email protected]> wrote:

[...]

Quoted 1 line

Quoted 1 line

It returns "status busy" after I type the command below.

Is this while other CPUs are active, or after you've hotplugged out all other CPUs? The latter is expected, but the former is not.

Are you able to hotplug CPU0 out and back in while other CPUs are active

[...]

For this bus you could instead use addresses relative to the bus inside, rather than absolute addresses,

or you could have:

ranges = <0x0 0x70000000 0x0 0x70000000 0x0 0x10000000>;

[...]

Quoted 3 lines

This initial patch is picked up from a very big dt file. There are several apb buses in this chip.

At the same level us the bus hierarchy?

Quoted 4 lines

So I use apb at starting-address to separate them.
But I remember another rule that the @address needs to equal first address in property reg array.
Do I have to delete @7000000 as well if i delete reg line?

Hmm. I'm not too keen on encoding a reg or unit-address here, because the control interface of the bus isn't at that address. If we want to add that later then the reg would be different in those cases. Given there's no control interface here, there shouldn't be a reg or unit-address.

Just ensure that the name before the unit-address is unique.

Thanks,
Mark.

From: Zhizhou Zhang <[email protected]>

Adds support for Spreadtrum's SoC Platform in the arm64 Kconfig and defconfig files.

Signed-off-by Zhizhou Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Signed-off-by Chunyan Zhang <[email protected]>

---
 arch/arm64/Kconfig           |    5 +++++
 arch/arm64/configs/defconfig |    1 +
 2 files changed, 6 insertions(+)

arch/arm64/Kconfig +0 -0

index b1f9a20..885c1f4 100644

arch/arm64/Kconfig +1 -0

+
 config ARCH_THUNDER
 	bool "Cavium Inc. Thunder SoC Family"
 	help

arch/arm64/configs/defconfig +1 -0

index dd301be..c1677ca 100644
@@ -33,6 +33,7 @@ CONFIG_MODULE_UNLOAD=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_IOSCHED_DEADLINE is not set
 CONFIG_ARCH_THUNDER=y
+CONFIG_ARCH_SPRD=y
 CONFIG_ARCH_VEXPRESS=y
 CONFIG_ARCH_XGENE=y
 CONFIG_PCI=y

Signature · 1 line

1.7.9.5

Quoted 18 lines · Chunyan Zhang

From: Zhizhou Zhang <[email protected]>

Adds support for Spreadtrum's SoC Platform in the arm64 Kconfig and defconfig files.

Signed-off-by Zhizhou Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Signed-off-by Chunyan Zhang <[email protected]>

---
 arch/arm64/Kconfig           |    5 +++++
 arch/arm64/configs/defconfig |    1 +
 2 files changed, 6 insertions(+)

arch/arm64/Kconfig +0 -0

index b1f9a20..885c1f4 100644

arch/arm64/Kconfig config ARCH_SEATTLE · line 156

Quoted 4 lines

arch/arm64/Kconfig +1 -0

@@ -153,6 +153,11 @@ config ARCH_SEATTLE
      help
        This enables support for AMD Seattle SOC Family
 
+config ARCH_SPRD

This should presumably be ARCH_SHARKL64, so you can add other SoC families later. The other entries in here are already formatted that way.

I wonder if we should have these of the form ARCH_${VENDOR}_${FAMILY} (e.g. ARCH_SPRD_SHARKL64) rather than just ARCH_${FAMILY} to save ourselves from name conflicts in future (and to make it easier to grep for a particular vendor's config options).

arch/arm64/Kconfig config ARCH_SEATTLE · line 157

Quoted 1 line

arch/arm64/Kconfig +1 -0

+     bool "Spreadtrum SoC platform"

bool "Spreadtrun Sharkl64 SoC Family"

arch/arm64/Kconfig config ARCH_SEATTLE · line 159

Quoted 2 lines

arch/arm64/Kconfig +2 -0

+     help
+       Support for Spreadtrum ARM based SoCs

Support for the Spreadtrum Sharkl64 SoC family.

Thanks,
Mark.

Quoted 1 line

arch/arm64/Kconfig +1 -0

+

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

Signed-off-by Chunyan Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Originally-by Lanqing Liu <[email protected]>

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

Signed-off-by Chunyan Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Originally-by Lanqing Liu <[email protected]>

---
 drivers/tty/serial/Kconfig       |   18 +
 drivers/tty/serial/Makefile      |    1 +
 drivers/tty/serial/sprd_serial.c |  772 ++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/serial_core.h |    3 +
 4 files changed, 794 insertions(+)
 create mode 100644 drivers/tty/serial/sprd_serial.c

drivers/tty/serial/Kconfig +18 -0

index c79b43c..969d3cd 100644
@@ -1577,6 +1577,24 @@ config SERIAL_MEN_Z135
 	  This driver can also be build as a module. If so, the module will be called
 	  men_z135_uart.ko
 
+config SERIAL_SPRD
+	tristate "Support for SPRD serial"
+	depends on ARCH_SPRD
+	select SERIAL_CORE
+	help
+	  This enables the driver for the Spreadtrum's serial.
+
+config SERIAL_SPRD_CONSOLE
+	bool "SPRD UART console support"
+	depends on SERIAL_SPRD=y
+	select SERIAL_CORE_CONSOLE
+	select SERIAL_EARLYCON
+	help
+	  Support for early debug console using Spreadtrum's serial. This enables
+	  the console before standard serial driver is probed. This is enabled
+	  with "earlycon" on the kernel command line. The console is
+	  enabled when early_param is processed.
+
 endmenu
 
 config SERIAL_MCTRL_GPIO

drivers/tty/serial/Makefile +1 -0

index 9a548ac..4801aca 100644
@@ -93,6 +93,7 @@ obj-$(CONFIG_SERIAL_ARC)	+= arc_uart.o
 obj-$(CONFIG_SERIAL_RP2)	+= rp2.o
 obj-$(CONFIG_SERIAL_FSL_LPUART)	+= fsl_lpuart.o
 obj-$(CONFIG_SERIAL_MEN_Z135)	+= men_z135_uart.o
+obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
 
 # GPIOLIB helpers for modem control lines
 obj-$(CONFIG_SERIAL_MCTRL_GPIO)	+= serial_mctrl_gpio.o

drivers/tty/serial/sprd_serial.c new file +274 -0

new file mode 100644
index 0000000..81839e4
@@ -0,0 +1,772 @@
+/*
+ * Copyright (C) 2012 Spreadtrum Communications Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+/* device name */
+#define UART_NR_MAX		8
+#define SPRD_TTY_NAME		"ttySPX"
+#define SPRD_FIFO_SIZE		128
+#define SPRD_DEF_RATE		26000000
+#define SPRD_TIMEOUT		2048
+
+/* the offset of serial registers and BITs for them */
+/* data registers */
+#define SPRD_TXD		0x0000
+#define SPRD_RXD		0x0004
+
+/* line status register and its BITs  */
+#define SPRD_LSR		0x0008
+#define SPRD_LSR_OE		BIT(4)
+#define SPRD_LSR_FE		BIT(3)
+#define SPRD_LSR_PE		BIT(2)
+#define SPRD_LSR_BI		BIT(7)
+#define SPRD_LSR_TX_OVER	BIT(15)
+
+/* data number in TX and RX fifo */
+#define SPRD_STS1		0x000C
+
+/* interrupt enable register and its BITs */
+#define SPRD_IEN		0x0010
+#define SPRD_IEN_RX_FULL	BIT(0)
+#define SPRD_IEN_TX_EMPTY	BIT(1)
+#define SPRD_IEN_BREAK_DETECT	BIT(7)
+#define SPRD_IEN_TIMEOUT	BIT(13)
+
+/* interrupt clear register */
+#define SPRD_ICLR		0x0014
+
+/* line control register */
+#define SPRD_LCR		0x0018
+#define SPRD_LCR_STOP_1BIT	0x10
+#define SPRD_LCR_STOP_2BIT	0x30
+#define SPRD_LCR_DATA_LEN	(BIT(2) | BIT(3))
+#define SPRD_LCR_DATA_LEN5	0x0
+#define SPRD_LCR_DATA_LEN6	0x4
+#define SPRD_LCR_DATA_LEN7	0x8
+#define SPRD_LCR_DATA_LEN8	0xc
+#define SPRD_LCR_PARITY		(BIT(0) | BIT(1))
+#define SPRD_LCR_PARITY_EN	0x2
+#define SPRD_LCR_EVEN_PAR	0x0
+#define SPRD_LCR_ODD_PAR	0x1
+
+/* control register 1 */
+#define SPRD_CTL1		0x001C
+#define RX_HW_FLOW_CTL_THLD	BIT(6)
+#define RX_HW_FLOW_CTL_EN	BIT(7)
+#define TX_HW_FLOW_CTL_EN	BIT(8)
+
+/* fifo threshold register */
+#define SPRD_CTL2		0x0020
+#define THLD_TX_EMPTY		0x40
+#define THLD_RX_FULL		0x40
+
+/* config baud rate register */
+#define SPRD_CLKD0		0x0024
+#define SPRD_CLKD1		0x0028
+
+/* interrupt mask status register */
+#define SPRD_IMSR		0x002C
+#define SPRD_IMSR_RX_FIFO_FULL	BIT(0)
+#define SPRD_IMSR_TX_FIFO_EMPTY	BIT(1)
+#define SPRD_IMSR_BREAK_DETECT	BIT(7)
+#define SPRD_IMSR_TIMEOUT	BIT(13)
+
+struct reg_backup {
+	uint32_t ien;
+	uint32_t ctrl0;
+	uint32_t ctrl1;
+	uint32_t ctrl2;
+	uint32_t clkd0;
+	uint32_t clkd1;
+	uint32_t dspwait;
+};
+
+struct sprd_uart_port {
+	struct uart_port port;
+	struct reg_backup reg_bak;
+	char name[16];
+};
+
+static struct sprd_uart_port *sprd_port[UART_NR_MAX] = { NULL };
+
+static inline unsigned int serial_in(struct uart_port *port, int offset)
+{
+	return readl_relaxed(port->membase + offset);
+}
+
+static inline void serial_out(struct uart_port *port, int offset, int value)
+{
+	writel_relaxed(value, port->membase + offset);
+}
+
+static unsigned int sprd_tx_empty(struct uart_port *port)
+{
+	if (serial_in(port, SPRD_STS1) & 0xff00)
+		return 0;
+	else
+		return TIOCSER_TEMT;
+}
+
+static unsigned int sprd_get_mctrl(struct uart_port *port)
+{
+	return TIOCM_DSR | TIOCM_CTS;
+}
+
+static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	/* nothing to do */
+}
+
+static void sprd_stop_tx(struct uart_port *port)
+{
+	unsigned int ien, iclr;
+
+	iclr = serial_in(port, SPRD_ICLR);
+	ien = serial_in(port, SPRD_IEN);
+
+	iclr |= SPRD_IEN_TX_EMPTY;
+	ien &= ~SPRD_IEN_TX_EMPTY;
+
+	serial_out(port, SPRD_ICLR, iclr);
+	serial_out(port, SPRD_IEN, ien);
+}
+
+static void sprd_start_tx(struct uart_port *port)
+{
+	unsigned int ien;
+
+	ien = serial_in(port, SPRD_IEN);
+	if (!(ien & SPRD_IEN_TX_EMPTY)) {
+		ien |= SPRD_IEN_TX_EMPTY;
+		serial_out(port, SPRD_IEN, ien);
+	}
+}
+
+static void sprd_stop_rx(struct uart_port *port)
+{
+	unsigned int ien, iclr;
+
+	iclr = serial_in(port, SPRD_ICLR);
+	ien = serial_in(port, SPRD_IEN);
+
+	ien &= ~(SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT);
+	iclr |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT;
+
+	serial_out(port, SPRD_IEN, ien);
+	serial_out(port, SPRD_ICLR, iclr);
+}
+
+/* The Sprd serial does not support this function. */
+static void sprd_break_ctl(struct uart_port *port, int break_state)
+{
+	/* nothing to do */
+}
+
+static inline int handle_lsr_errors(struct uart_port *port,
+				    unsigned int *flag,
+				    unsigned int *lsr)
+{
+	int ret = 0;
+
+	/* statistics */
+	if (*lsr & SPRD_LSR_BI) {
+		*lsr &= ~(SPRD_LSR_FE | SPRD_LSR_PE);
+		port->icount.brk++;
+		ret = uart_handle_break(port);
+		if (ret)
+			return ret;
+	} else if (*lsr & SPRD_LSR_PE)
+		port->icount.parity++;
+	else if (*lsr & SPRD_LSR_FE)
+		port->icount.frame++;
+	if (*lsr & SPRD_LSR_OE)
+		port->icount.overrun++;
+
+	/* mask off conditions which should be ignored */
+	*lsr &= port->read_status_mask;
+	if (*lsr & SPRD_LSR_BI)
+		*flag = TTY_BREAK;
+	else if (*lsr & SPRD_LSR_PE)
+		*flag = TTY_PARITY;
+	else if (*lsr & SPRD_LSR_FE)
+		*flag = TTY_FRAME;
+
+	return ret;
+}
+
+static inline void sprd_rx(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	struct tty_port *tty = &port->state->port;
+	unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT;
+
+	while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) {
+		lsr = serial_in(port, SPRD_LSR);
+		ch = serial_in(port, SPRD_RXD);
+		flag = TTY_NORMAL;
+		port->icount.rx++;
+
+		if (lsr & (SPRD_LSR_BI | SPRD_LSR_PE
+			| SPRD_LSR_FE | SPRD_LSR_OE))
+			if (handle_lsr_errors(port, &lsr, &flag))
+				continue;
+		if (uart_handle_sysrq_char(port, ch))
+			continue;
+
+		uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
+	}
+
+	tty_flip_buffer_push(tty);
+}
+
+static inline void sprd_tx(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	struct circ_buf *xmit = &port->state->xmit;
+	int count;
+
+	if (port->x_char) {
+		serial_out(port, SPRD_TXD, port->x_char);
+		port->icount.tx++;
+		port->x_char = 0;
+		return;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+		sprd_stop_tx(port);
+		return;
+	}
+
+	count = THLD_TX_EMPTY;
+	do {
+		serial_out(port, SPRD_TXD, xmit->buf[xmit->tail]);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+		if (uart_circ_empty(xmit))
+			break;
+	} while (--count > 0);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);

drivers/tty/serial/sprd_serial.c new file +111 -0

+	ims = serial_in(port, SPRD_IMSR);
+
+	if (!ims)
+		return IRQ_NONE;
+
+	serial_out(port, SPRD_ICLR, ~0);
+
+	if (ims & (SPRD_IMSR_RX_FIFO_FULL |
+		SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT))
+		sprd_rx(irq, port);
+
+	if (ims & SPRD_IMSR_TX_FIFO_EMPTY)
+		sprd_tx(irq, port);
+
+	return IRQ_HANDLED;
+}
+
+static int sprd_startup(struct uart_port *port)
+{
+	int ret = 0;
+	unsigned int ien, ctrl1;
+	unsigned int timeout;
+	struct sprd_uart_port *sp;
+
+	serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY << 8) | THLD_RX_FULL));
+
+	/* clear rx fifo */
+	timeout = SPRD_TIMEOUT;
+	while (timeout-- && serial_in(port, SPRD_STS1) & 0x00ff)
+		serial_in(port, SPRD_RXD);
+
+	/* clear tx fifo */
+	timeout = SPRD_TIMEOUT;
+	while (timeout-- && serial_in(port, SPRD_STS1) & 0xff00)
+		cpu_relax();
+
+	/* clear interrupt */
+	serial_out(port, SPRD_IEN, 0x0);
+	serial_out(port, SPRD_ICLR, ~0);
+
+	/* allocate irq */
+	sp = container_of(port, struct sprd_uart_port, port);
+	snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line);
+	ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq,
+				IRQF_SHARED, sp->name, port);
+	if (ret) {
+		dev_err(port->dev, "fail to request serial irq %d, ret=%d\n",
+			port->irq, ret);
+		return ret;
+	}
+	ctrl1 = serial_in(port, SPRD_CTL1);
+	ctrl1 |= 0x3e00 | THLD_RX_FULL;
+	serial_out(port, SPRD_CTL1, ctrl1);
+
+	/* enable interrupt */
+	spin_lock(&port->lock);
+	ien = serial_in(port, SPRD_IEN);
+	ien |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT;
+	serial_out(port, SPRD_IEN, ien);
+	spin_unlock(&port->lock);
+
+	return 0;
+}
+
+static void sprd_shutdown(struct uart_port *port)
+{
+	serial_out(port, SPRD_IEN, 0x0);
+	serial_out(port, SPRD_ICLR, ~0);
+	devm_free_irq(port->dev, port->irq, port);
+}
+
+static void sprd_set_termios(struct uart_port *port,
+				    struct ktermios *termios,
+				    struct ktermios *old)
+{
+	unsigned int baud, quot;
+	unsigned int lcr, fc;
+
+	/* ask the core to calculate the divisor for us */
+	baud = uart_get_baud_rate(port, termios, old, 1200, 3000000);
+
+	quot = (unsigned int)((port->uartclk + baud / 2) / baud);
+
+	/* set data length */
+	lcr = serial_in(port, SPRD_LCR);
+	lcr &= ~SPRD_LCR_DATA_LEN;
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		lcr |= SPRD_LCR_DATA_LEN5;
+		break;
+	case CS6:
+		lcr |= SPRD_LCR_DATA_LEN6;
+		break;
+	case CS7:
+		lcr |= SPRD_LCR_DATA_LEN7;
+		break;
+	case CS8:
+	default:
+		lcr |= SPRD_LCR_DATA_LEN8;
+		break;
+	}
+
+	/* calculate stop bits */
+	lcr &= ~(SPRD_LCR_STOP_1BIT | SPRD_LCR_STOP_2BIT);
+	if (termios->c_cflag & CSTOPB)
+		lcr |= SPRD_LCR_STOP_2BIT;
+	else
+		lcr |= SPRD_LCR_STOP_1BIT;
+
+	/* calculate parity */
+	lcr &= ~SPRD_LCR_PARITY;

drivers/tty/serial/sprd_serial.c new file +30 -0

+	/* update the per-port timeout */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	port->read_status_mask = SPRD_LSR_OE;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= SPRD_LSR_FE | SPRD_LSR_PE;
+	if (termios->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= SPRD_LSR_BI;
+
+	/* characters to ignore */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= SPRD_LSR_PE | SPRD_LSR_FE;
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= SPRD_LSR_BI;
+		/*
+		 * If we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= SPRD_LSR_OE;
+	}
+
+	/* flow control */
+	fc = serial_in(port, SPRD_CTL1);
+	fc &= ~(RX_HW_FLOW_CTL_THLD | RX_HW_FLOW_CTL_EN | TX_HW_FLOW_CTL_EN);
+	if (termios->c_cflag & CRTSCTS) {
+		fc |= RX_HW_FLOW_CTL_THLD;
+		fc |= RX_HW_FLOW_CTL_EN;
+		fc |= TX_HW_FLOW_CTL_EN;

drivers/tty/serial/sprd_serial.c new file +75 -0

+	/* Don't rewrite B0 */
+	if (tty_termios_baud_rate(termios))
+		tty_termios_encode_baud_rate(termios, baud, baud);
+}
+
+static const char *sprd_type(struct uart_port *port)
+{
+	return "SPX";
+}
+
+static void sprd_release_port(struct uart_port *port)
+{
+	/* nothing to do */
+}
+
+static int sprd_request_port(struct uart_port *port)
+{
+	return 0;
+}
+
+static void sprd_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE)
+		port->type = PORT_SPRD;
+}
+
+static int sprd_verify_port(struct uart_port *port,
+				   struct serial_struct *ser)
+{
+	if (ser->type != PORT_SPRD)
+		return -EINVAL;
+	if (port->irq != ser->irq)
+		return -EINVAL;
+	return 0;
+}
+
+static struct uart_ops serial_sprd_ops = {
+	.tx_empty = sprd_tx_empty,
+	.get_mctrl = sprd_get_mctrl,
+	.set_mctrl = sprd_set_mctrl,
+	.stop_tx = sprd_stop_tx,
+	.start_tx = sprd_start_tx,
+	.stop_rx = sprd_stop_rx,
+	.break_ctl = sprd_break_ctl,
+	.startup = sprd_startup,
+	.shutdown = sprd_shutdown,
+	.set_termios = sprd_set_termios,
+	.type = sprd_type,
+	.release_port = sprd_release_port,
+	.request_port = sprd_request_port,
+	.config_port = sprd_config_port,
+	.verify_port = sprd_verify_port,
+};
+
+#ifdef CONFIG_SERIAL_SPRD_CONSOLE
+static inline void wait_for_xmitr(struct uart_port *port)
+{
+	unsigned int status, tmout = 10000;
+
+	/* wait up to 10ms for the character(s) to be sent */
+	do {
+		status = serial_in(port, SPRD_STS1);
+		if (--tmout == 0)
+			break;
+		udelay(1);
+	} while (status & 0xff00);
+}
+
+static void sprd_console_putchar(struct uart_port *port, int ch)
+{
+	wait_for_xmitr(port);
+	serial_out(port, SPRD_TXD, ch);
+}
+
+static void sprd_console_write(struct console *co, const char *s,

drivers/tty/serial/sprd_serial.c new file +163 -0

+	/* save the IEN then disable the interrupts */
+	ien = serial_in(port, SPRD_IEN);
+	serial_out(port, SPRD_IEN, 0x0);
+
+	uart_console_write(port, s, count, sprd_console_putchar);
+
+	/* wait for transmitter to become empty and restore the IEN */
+	wait_for_xmitr(port);
+	serial_out(port, SPRD_IEN, ien);
+	if (locked)
+		spin_unlock(&port->lock);
+}
+
+static int __init sprd_console_setup(struct console *co, char *options)
+{
+	struct uart_port *port;
+	int baud = 115200;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (co->index >= UART_NR_MAX || co->index < 0)
+		co->index = 0;
+
+	port = &sprd_port[co->index]->port;
+	if (port == NULL) {
+		pr_info("serial port %d not yet initialized\n", co->index);
+		return -ENODEV;
+	}
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver sprd_uart_driver;
+static struct console sprd_console = {
+	.name = SPRD_TTY_NAME,
+	.write = sprd_console_write,
+	.device = uart_console_device,
+	.setup = sprd_console_setup,
+	.flags = CON_PRINTBUFFER,
+	.index = -1,
+	.data = &sprd_uart_driver,
+};
+
+#define SPRD_CONSOLE	(&sprd_console)
+
+/* Support for earlycon */
+static void sprd_putc(struct uart_port *port, int c)
+{
+	unsigned int timeout = SPRD_TIMEOUT;
+
+	while (timeout-- &&
+		   !(readl(port->membase + SPRD_LSR) & SPRD_LSR_TX_OVER))
+		cpu_relax();
+
+	writeb(c, port->membase + SPRD_TXD);
+}
+
+static void sprd_early_write(struct console *con, const char *s,
+				    unsigned n)
+{
+	struct earlycon_device *dev = con->data;
+
+	uart_console_write(&dev->port, s, n, sprd_putc);
+}
+
+static int __init sprd_early_console_setup(
+				struct earlycon_device *device,
+				const char *opt)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	device->con->write = sprd_early_write;
+	return 0;
+}
+
+EARLYCON_DECLARE(sprd_serial, sprd_early_console_setup);
+OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart",
+		    sprd_early_console_setup);
+
+#else /* !CONFIG_SERIAL_SPRD_CONSOLE */
+#define SPRD_CONSOLE		NULL
+#endif
+
+static struct uart_driver sprd_uart_driver = {
+	.owner = THIS_MODULE,
+	.driver_name = "sprd_serial",
+	.dev_name = SPRD_TTY_NAME,
+	.major = 0,
+	.minor = 0,
+	.nr = UART_NR_MAX,
+	.cons = SPRD_CONSOLE,
+};
+
+static int sprd_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct device_node *np = pdev->dev.of_node;
+	struct uart_port *up;
+	struct clk *clk;
+	int irq;
+
+	if (np)
+		pdev->id = of_alias_get_id(np, "serial");
+
+	if (pdev->id < 0 || pdev->id >= UART_NR_MAX) {
+		dev_err(&pdev->dev, "does not support id %d\n", pdev->id);
+		return -ENXIO;
+	}
+
+	sprd_port[pdev->id] = devm_kzalloc(&pdev->dev,
+		sizeof(*sprd_port[pdev->id]), GFP_KERNEL);
+	if (!sprd_port[pdev->id])
+		return -ENOMEM;
+
+	up = &sprd_port[pdev->id]->port;
+	up->dev = &pdev->dev;
+	up->line = pdev->id;
+	up->type = PORT_SPRD;
+	up->iotype = SERIAL_IO_PORT;
+	up->uartclk = SPRD_DEF_RATE;
+	up->fifosize = SPRD_FIFO_SIZE;
+	up->ops = &serial_sprd_ops;
+	up->flags = ASYNC_BOOT_AUTOCONF;
+
+	clk = devm_clk_get(&pdev->dev, NULL);
+	if (!IS_ERR(clk))
+		up->uartclk = clk_get_rate(clk);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "not provide mem resource\n");
+		return -ENODEV;
+	}
+	up->mapbase = res->start;
+	up->membase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(up->membase))
+		return PTR_ERR(up->membase);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "not provide irq resource\n");
+		return -ENODEV;
+	}
+	up->irq = irq;
+
+	platform_set_drvdata(pdev, up);
+
+	return uart_add_one_port(&sprd_uart_driver, up);
+}
+
+static int sprd_remove(struct platform_device *dev)
+{
+	struct uart_port *up = platform_get_drvdata(dev);
+
+	return uart_remove_one_port(&sprd_uart_driver, up);
+}
+
+static int sprd_suspend(struct device *dev)
+{

drivers/tty/serial/sprd_serial.c new file +67 -0

+
+	uart_suspend_port(&sprd_uart_driver, port);
+
+	return 0;
+}
+
+static int sprd_resume(struct device *dev)
+{
+	int id = to_platform_device(dev)->id;
+	struct uart_port *port = &sprd_port[id]->port;
+	struct reg_backup *reg_bak = &sprd_port[id]->reg_bak;
+
+	serial_out(port, SPRD_LCR, reg_bak->ctrl0);
+	serial_out(port, SPRD_CTL1, reg_bak->ctrl1);
+	serial_out(port, SPRD_CTL2, reg_bak->ctrl2);
+	serial_out(port, SPRD_CLKD0, reg_bak->clkd0);
+	serial_out(port, SPRD_CLKD1, reg_bak->clkd1);
+	serial_out(port, SPRD_IEN, reg_bak->ien);
+
+	uart_resume_port(&sprd_uart_driver, port);
+
+	return 0;
+}
+
+static const struct of_device_id serial_ids[] = {
+	{.compatible = "sprd,sc9836-uart",},
+	{}
+};
+
+static SIMPLE_DEV_PM_OPS(sprd_pm_ops, sprd_suspend, sprd_resume);
+
+static struct platform_driver sprd_platform_driver = {
+	.probe		= sprd_probe,
+	.remove		= sprd_remove,
+	.driver 	= {
+		.name	= "sprd_serial",
+		.of_match_table = of_match_ptr(serial_ids),
+		.pm	= &sprd_pm_ops,
+	},
+};
+
+static int __init sprd_serial_init(void)
+{
+	int ret = 0;
+
+	ret = uart_register_driver(&sprd_uart_driver);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&sprd_platform_driver);
+	if (ret)
+		uart_unregister_driver(&sprd_uart_driver);
+
+	return ret;
+}
+
+static void __exit sprd_serial_exit(void)
+{
+	platform_driver_unregister(&sprd_platform_driver);
+	uart_unregister_driver(&sprd_uart_driver);
+}
+
+module_init(sprd_serial_init);
+module_exit(sprd_serial_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Spreadtrum SoC serial driver series");

include/uapi/linux/serial_core.h +3 -0

index c172180..7e6eb39 100644
@@ -248,4 +248,7 @@
 /* MESON */
 #define PORT_MESON	109
 
+/* SPRD SERIAL  */
+#define PORT_SPRD	110
+
 #endif /* _UAPILINUX_SERIAL_CORE_H */

Quoted 5 lines · Chunyan Zhang

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

The locking doesn't look correct. Specific notations below.

Quoted 335 lines

Signed-off-by Chunyan Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Originally-by Lanqing Liu <[email protected]>

---
  drivers/tty/serial/Kconfig       |   18 +
  drivers/tty/serial/Makefile      |    1 +
  drivers/tty/serial/sprd_serial.c |  772 ++++++++++++++++++++++++++++++++++++++
  include/uapi/linux/serial_core.h |    3 +
  4 files changed, 794 insertions(+)

create mode 100644 drivers/tty/serial/sprd_serial.c

drivers/tty/serial/Kconfig +18 -0

index c79b43c..969d3cd 100644
@@ -1577,6 +1577,24 @@ config SERIAL_MEN_Z135
  	  This driver can also be build as a module. If so, the module will be called
  	  men_z135_uart.ko
 
+config SERIAL_SPRD
+	tristate "Support for SPRD serial"
+	depends on ARCH_SPRD
+	select SERIAL_CORE
+	help
+	  This enables the driver for the Spreadtrum's serial.
+
+config SERIAL_SPRD_CONSOLE
+	bool "SPRD UART console support"
+	depends on SERIAL_SPRD=y
+	select SERIAL_CORE_CONSOLE
+	select SERIAL_EARLYCON
+	help
+	  Support for early debug console using Spreadtrum's serial. This enables
+	  the console before standard serial driver is probed. This is enabled
+	  with "earlycon" on the kernel command line. The console is
+	  enabled when early_param is processed.
+
  endmenu
 
  config SERIAL_MCTRL_GPIO

drivers/tty/serial/Makefile +1 -0

index 9a548ac..4801aca 100644
@@ -93,6 +93,7 @@ obj-$(CONFIG_SERIAL_ARC)	+= arc_uart.o
  obj-$(CONFIG_SERIAL_RP2)	+= rp2.o
  obj-$(CONFIG_SERIAL_FSL_LPUART)	+= fsl_lpuart.o
  obj-$(CONFIG_SERIAL_MEN_Z135)	+= men_z135_uart.o
+obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
 
  # GPIOLIB helpers for modem control lines
  obj-$(CONFIG_SERIAL_MCTRL_GPIO)	+= serial_mctrl_gpio.o

drivers/tty/serial/sprd_serial.c new file +277 -0

new file mode 100644
index 0000000..81839e4
@@ -0,0 +1,772 @@
+/*
+ * Copyright (C) 2012 Spreadtrum Communications Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+/* device name */
+#define UART_NR_MAX		8
+#define SPRD_TTY_NAME		"ttySPX"
+#define SPRD_FIFO_SIZE		128
+#define SPRD_DEF_RATE		26000000
+#define SPRD_TIMEOUT		2048
+
+/* the offset of serial registers and BITs for them */
+/* data registers */
+#define SPRD_TXD		0x0000
+#define SPRD_RXD		0x0004
+
+/* line status register and its BITs  */
+#define SPRD_LSR		0x0008
+#define SPRD_LSR_OE		BIT(4)
+#define SPRD_LSR_FE		BIT(3)
+#define SPRD_LSR_PE		BIT(2)
+#define SPRD_LSR_BI		BIT(7)
+#define SPRD_LSR_TX_OVER	BIT(15)
+
+/* data number in TX and RX fifo */
+#define SPRD_STS1		0x000C
+
+/* interrupt enable register and its BITs */
+#define SPRD_IEN		0x0010
+#define SPRD_IEN_RX_FULL	BIT(0)
+#define SPRD_IEN_TX_EMPTY	BIT(1)
+#define SPRD_IEN_BREAK_DETECT	BIT(7)
+#define SPRD_IEN_TIMEOUT	BIT(13)
+
+/* interrupt clear register */
+#define SPRD_ICLR		0x0014
+
+/* line control register */
+#define SPRD_LCR		0x0018
+#define SPRD_LCR_STOP_1BIT	0x10
+#define SPRD_LCR_STOP_2BIT	0x30
+#define SPRD_LCR_DATA_LEN	(BIT(2) | BIT(3))
+#define SPRD_LCR_DATA_LEN5	0x0
+#define SPRD_LCR_DATA_LEN6	0x4
+#define SPRD_LCR_DATA_LEN7	0x8
+#define SPRD_LCR_DATA_LEN8	0xc
+#define SPRD_LCR_PARITY		(BIT(0) | BIT(1))
+#define SPRD_LCR_PARITY_EN	0x2
+#define SPRD_LCR_EVEN_PAR	0x0
+#define SPRD_LCR_ODD_PAR	0x1
+
+/* control register 1 */
+#define SPRD_CTL1		0x001C
+#define RX_HW_FLOW_CTL_THLD	BIT(6)
+#define RX_HW_FLOW_CTL_EN	BIT(7)
+#define TX_HW_FLOW_CTL_EN	BIT(8)
+
+/* fifo threshold register */
+#define SPRD_CTL2		0x0020
+#define THLD_TX_EMPTY		0x40
+#define THLD_RX_FULL		0x40
+
+/* config baud rate register */
+#define SPRD_CLKD0		0x0024
+#define SPRD_CLKD1		0x0028
+
+/* interrupt mask status register */
+#define SPRD_IMSR		0x002C
+#define SPRD_IMSR_RX_FIFO_FULL	BIT(0)
+#define SPRD_IMSR_TX_FIFO_EMPTY	BIT(1)
+#define SPRD_IMSR_BREAK_DETECT	BIT(7)
+#define SPRD_IMSR_TIMEOUT	BIT(13)
+
+struct reg_backup {
+	uint32_t ien;
+	uint32_t ctrl0;
+	uint32_t ctrl1;
+	uint32_t ctrl2;
+	uint32_t clkd0;
+	uint32_t clkd1;
+	uint32_t dspwait;
+};
+
+struct sprd_uart_port {
+	struct uart_port port;
+	struct reg_backup reg_bak;
+	char name[16];
+};
+
+static struct sprd_uart_port *sprd_port[UART_NR_MAX] = { NULL };
+
+static inline unsigned int serial_in(struct uart_port *port, int offset)
+{
+	return readl_relaxed(port->membase + offset);
+}
+
+static inline void serial_out(struct uart_port *port, int offset, int value)
+{
+	writel_relaxed(value, port->membase + offset);
+}
+
+static unsigned int sprd_tx_empty(struct uart_port *port)
+{
+	if (serial_in(port, SPRD_STS1) & 0xff00)
+		return 0;
+	else
+		return TIOCSER_TEMT;
+}
+
+static unsigned int sprd_get_mctrl(struct uart_port *port)
+{
+	return TIOCM_DSR | TIOCM_CTS;
+}
+
+static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	/* nothing to do */
+}
+
+static void sprd_stop_tx(struct uart_port *port)
+{
+	unsigned int ien, iclr;
+
+	iclr = serial_in(port, SPRD_ICLR);
+	ien = serial_in(port, SPRD_IEN);
+
+	iclr |= SPRD_IEN_TX_EMPTY;
+	ien &= ~SPRD_IEN_TX_EMPTY;
+
+	serial_out(port, SPRD_ICLR, iclr);
+	serial_out(port, SPRD_IEN, ien);
+}
+
+static void sprd_start_tx(struct uart_port *port)
+{
+	unsigned int ien;
+
+	ien = serial_in(port, SPRD_IEN);
+	if (!(ien & SPRD_IEN_TX_EMPTY)) {
+		ien |= SPRD_IEN_TX_EMPTY;
+		serial_out(port, SPRD_IEN, ien);
+	}
+}
+
+static void sprd_stop_rx(struct uart_port *port)
+{
+	unsigned int ien, iclr;
+
+	iclr = serial_in(port, SPRD_ICLR);
+	ien = serial_in(port, SPRD_IEN);
+
+	ien &= ~(SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT);
+	iclr |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT;
+
+	serial_out(port, SPRD_IEN, ien);
+	serial_out(port, SPRD_ICLR, iclr);
+}
+
+/* The Sprd serial does not support this function. */
+static void sprd_break_ctl(struct uart_port *port, int break_state)
+{
+	/* nothing to do */
+}
+
+static inline int handle_lsr_errors(struct uart_port *port,
+				    unsigned int *flag,
+				    unsigned int *lsr)
+{
+	int ret = 0;
+
+	/* statistics */
+	if (*lsr & SPRD_LSR_BI) {
+		*lsr &= ~(SPRD_LSR_FE | SPRD_LSR_PE);
+		port->icount.brk++;
+		ret = uart_handle_break(port);
+		if (ret)
+			return ret;
+	} else if (*lsr & SPRD_LSR_PE)
+		port->icount.parity++;
+	else if (*lsr & SPRD_LSR_FE)
+		port->icount.frame++;
+	if (*lsr & SPRD_LSR_OE)
+		port->icount.overrun++;
+
+	/* mask off conditions which should be ignored */
+	*lsr &= port->read_status_mask;
+	if (*lsr & SPRD_LSR_BI)
+		*flag = TTY_BREAK;
+	else if (*lsr & SPRD_LSR_PE)
+		*flag = TTY_PARITY;
+	else if (*lsr & SPRD_LSR_FE)
+		*flag = TTY_FRAME;
+
+	return ret;
+}
+
+static inline void sprd_rx(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	struct tty_port *tty = &port->state->port;
+	unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT;
+
+	while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) {
+		lsr = serial_in(port, SPRD_LSR);
+		ch = serial_in(port, SPRD_RXD);
+		flag = TTY_NORMAL;
+		port->icount.rx++;
+
+		if (lsr & (SPRD_LSR_BI | SPRD_LSR_PE
+			| SPRD_LSR_FE | SPRD_LSR_OE))
+			if (handle_lsr_errors(port, &lsr, &flag))
+				continue;
+		if (uart_handle_sysrq_char(port, ch))
+			continue;
+
+		uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
+	}
+
+	tty_flip_buffer_push(tty);
+}
+
+static inline void sprd_tx(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	struct circ_buf *xmit = &port->state->xmit;
+	int count;
+
+	if (port->x_char) {
+		serial_out(port, SPRD_TXD, port->x_char);
+		port->icount.tx++;
+		port->x_char = 0;
+		return;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+		sprd_stop_tx(port);
+		return;
+	}
+
+	count = THLD_TX_EMPTY;
+	do {
+		serial_out(port, SPRD_TXD, xmit->buf[xmit->tail]);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+		if (uart_circ_empty(xmit))
+			break;
+	} while (--count > 0);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (uart_circ_empty(xmit))
+		sprd_stop_tx(port);

drivers/tty/serial/sprd_serial.c line 284

Quoted 7 lines

drivers/tty/serial/sprd_serial.c new file +7 -0

+}
+
+/* this handles the interrupt from one port */
+static irqreturn_t sprd_handle_irq(int irq, void *dev_id)
+{
+	struct uart_port *port = (struct uart_port *)dev_id;
+	unsigned int ims;

Why does your isr not have to take port->lock ?

Quoted 112 lines

drivers/tty/serial/sprd_serial.c new file +111 -0

+	ims = serial_in(port, SPRD_IMSR);
+
+	if (!ims)
+		return IRQ_NONE;
+
+	serial_out(port, SPRD_ICLR, ~0);
+
+	if (ims & (SPRD_IMSR_RX_FIFO_FULL |
+		SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT))
+		sprd_rx(irq, port);
+
+	if (ims & SPRD_IMSR_TX_FIFO_EMPTY)
+		sprd_tx(irq, port);
+
+	return IRQ_HANDLED;
+}
+
+static int sprd_startup(struct uart_port *port)
+{
+	int ret = 0;
+	unsigned int ien, ctrl1;
+	unsigned int timeout;
+	struct sprd_uart_port *sp;
+
+	serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY << 8) | THLD_RX_FULL));
+
+	/* clear rx fifo */
+	timeout = SPRD_TIMEOUT;
+	while (timeout-- && serial_in(port, SPRD_STS1) & 0x00ff)
+		serial_in(port, SPRD_RXD);
+
+	/* clear tx fifo */
+	timeout = SPRD_TIMEOUT;
+	while (timeout-- && serial_in(port, SPRD_STS1) & 0xff00)
+		cpu_relax();
+
+	/* clear interrupt */
+	serial_out(port, SPRD_IEN, 0x0);
+	serial_out(port, SPRD_ICLR, ~0);
+
+	/* allocate irq */
+	sp = container_of(port, struct sprd_uart_port, port);
+	snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line);
+	ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq,
+				IRQF_SHARED, sp->name, port);
+	if (ret) {
+		dev_err(port->dev, "fail to request serial irq %d, ret=%d\n",
+			port->irq, ret);
+		return ret;
+	}
+	ctrl1 = serial_in(port, SPRD_CTL1);
+	ctrl1 |= 0x3e00 | THLD_RX_FULL;
+	serial_out(port, SPRD_CTL1, ctrl1);
+
+	/* enable interrupt */
+	spin_lock(&port->lock);
+	ien = serial_in(port, SPRD_IEN);
+	ien |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT;
+	serial_out(port, SPRD_IEN, ien);
+	spin_unlock(&port->lock);
+
+	return 0;
+}
+
+static void sprd_shutdown(struct uart_port *port)
+{
+	serial_out(port, SPRD_IEN, 0x0);
+	serial_out(port, SPRD_ICLR, ~0);
+	devm_free_irq(port->dev, port->irq, port);
+}
+
+static void sprd_set_termios(struct uart_port *port,
+				    struct ktermios *termios,
+				    struct ktermios *old)
+{
+	unsigned int baud, quot;
+	unsigned int lcr, fc;
+
+	/* ask the core to calculate the divisor for us */
+	baud = uart_get_baud_rate(port, termios, old, 1200, 3000000);
+
+	quot = (unsigned int)((port->uartclk + baud / 2) / baud);
+
+	/* set data length */
+	lcr = serial_in(port, SPRD_LCR);
+	lcr &= ~SPRD_LCR_DATA_LEN;
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		lcr |= SPRD_LCR_DATA_LEN5;
+		break;
+	case CS6:
+		lcr |= SPRD_LCR_DATA_LEN6;
+		break;
+	case CS7:
+		lcr |= SPRD_LCR_DATA_LEN7;
+		break;
+	case CS8:
+	default:
+		lcr |= SPRD_LCR_DATA_LEN8;
+		break;
+	}
+
+	/* calculate stop bits */
+	lcr &= ~(SPRD_LCR_STOP_1BIT | SPRD_LCR_STOP_2BIT);
+	if (termios->c_cflag & CSTOPB)
+		lcr |= SPRD_LCR_STOP_2BIT;
+	else
+		lcr |= SPRD_LCR_STOP_1BIT;
+
+	/* calculate parity */
+	lcr &= ~SPRD_LCR_PARITY;

drivers/tty/serial/sprd_serial.c line 406

Quoted 10 lines

drivers/tty/serial/sprd_serial.c new file +10 -0

+	termios->c_cflag &= ~CMSPAR;	/* no support mark/space */
+	if (termios->c_cflag & PARENB) {
+		lcr |= SPRD_LCR_PARITY_EN;
+		if (termios->c_cflag & PARODD)
+			lcr |= SPRD_LCR_ODD_PAR;
+		else
+			lcr |= SPRD_LCR_EVEN_PAR;
+	}
+
+	/* change the port state. */

            ^^^^^^^^^^^^^^^^^^^^^^

This means you should be taking the port->lock here... (and disabling local interrupts if your isr takes the port->lock)

Quoted 31 lines

drivers/tty/serial/sprd_serial.c new file +30 -0

+	/* update the per-port timeout */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	port->read_status_mask = SPRD_LSR_OE;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= SPRD_LSR_FE | SPRD_LSR_PE;
+	if (termios->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= SPRD_LSR_BI;
+
+	/* characters to ignore */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= SPRD_LSR_PE | SPRD_LSR_FE;
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= SPRD_LSR_BI;
+		/*
+		 * If we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= SPRD_LSR_OE;
+	}
+
+	/* flow control */
+	fc = serial_in(port, SPRD_CTL1);
+	fc &= ~(RX_HW_FLOW_CTL_THLD | RX_HW_FLOW_CTL_EN | TX_HW_FLOW_CTL_EN);
+	if (termios->c_cflag & CRTSCTS) {
+		fc |= RX_HW_FLOW_CTL_THLD;
+		fc |= RX_HW_FLOW_CTL_EN;
+		fc |= TX_HW_FLOW_CTL_EN;

drivers/tty/serial/sprd_serial.c line 446

Quoted 10 lines

drivers/tty/serial/sprd_serial.c new file +10 -0

+	}
+
+	/* clock divider bit0~bit15 */
+	serial_out(port, SPRD_CLKD0, quot & 0xffff);
+
+	/* clock divider bit16~bit20 */
+	serial_out(port, SPRD_CLKD1, (quot & 0x1f0000) >> 16);
+	serial_out(port, SPRD_LCR, lcr);
+	fc |= 0x3e00 | THLD_RX_FULL;
+	serial_out(port, SPRD_CTL1, fc);

and dropping it here.

Quoted 79 lines

drivers/tty/serial/sprd_serial.c new file +79 -0

+	/* Don't rewrite B0 */
+	if (tty_termios_baud_rate(termios))
+		tty_termios_encode_baud_rate(termios, baud, baud);
+}
+
+static const char *sprd_type(struct uart_port *port)
+{
+	return "SPX";
+}
+
+static void sprd_release_port(struct uart_port *port)
+{
+	/* nothing to do */
+}
+
+static int sprd_request_port(struct uart_port *port)
+{
+	return 0;
+}
+
+static void sprd_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE)
+		port->type = PORT_SPRD;
+}
+
+static int sprd_verify_port(struct uart_port *port,
+				   struct serial_struct *ser)
+{
+	if (ser->type != PORT_SPRD)
+		return -EINVAL;
+	if (port->irq != ser->irq)
+		return -EINVAL;
+	return 0;
+}
+
+static struct uart_ops serial_sprd_ops = {
+	.tx_empty = sprd_tx_empty,
+	.get_mctrl = sprd_get_mctrl,
+	.set_mctrl = sprd_set_mctrl,
+	.stop_tx = sprd_stop_tx,
+	.start_tx = sprd_start_tx,
+	.stop_rx = sprd_stop_rx,
+	.break_ctl = sprd_break_ctl,
+	.startup = sprd_startup,
+	.shutdown = sprd_shutdown,
+	.set_termios = sprd_set_termios,
+	.type = sprd_type,
+	.release_port = sprd_release_port,
+	.request_port = sprd_request_port,
+	.config_port = sprd_config_port,
+	.verify_port = sprd_verify_port,
+};
+
+#ifdef CONFIG_SERIAL_SPRD_CONSOLE
+static inline void wait_for_xmitr(struct uart_port *port)
+{
+	unsigned int status, tmout = 10000;
+
+	/* wait up to 10ms for the character(s) to be sent */
+	do {
+		status = serial_in(port, SPRD_STS1);
+		if (--tmout == 0)
+			break;
+		udelay(1);
+	} while (status & 0xff00);
+}
+
+static void sprd_console_putchar(struct uart_port *port, int ch)
+{
+	wait_for_xmitr(port);
+	serial_out(port, SPRD_TXD, ch);
+}
+
+static void sprd_console_write(struct console *co, const char *s,
+				      unsigned int count)
+{
+	struct uart_port *port = &sprd_port[co->index]->port;
+	int ien;

drivers/tty/serial/sprd_serial.c line 532

Quoted 6 lines

drivers/tty/serial/sprd_serial.c new file +6 -0

+	int locked = 1;
+
+	if (oops_in_progress)
+		locked = spin_trylock(&port->lock);
+	else
+		spin_lock(&port->lock);

If you do need to take the port->lock in your isr, then you need to disable local irq here.

drivers/tty/serial/sprd_serial.c line 535

Quoted 4 lines

drivers/tty/serial/sprd_serial.c new file +3 -0

+	/* save the IEN then disable the interrupts */
+	ien = serial_in(port, SPRD_IEN);
+	serial_out(port, SPRD_IEN, 0x0);

Quoted 160 lines

drivers/tty/serial/sprd_serial.c new file +160 -0

+
+	uart_console_write(port, s, count, sprd_console_putchar);
+
+	/* wait for transmitter to become empty and restore the IEN */
+	wait_for_xmitr(port);
+	serial_out(port, SPRD_IEN, ien);
+	if (locked)
+		spin_unlock(&port->lock);
+}
+
+static int __init sprd_console_setup(struct console *co, char *options)
+{
+	struct uart_port *port;
+	int baud = 115200;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if (co->index >= UART_NR_MAX || co->index < 0)
+		co->index = 0;
+
+	port = &sprd_port[co->index]->port;
+	if (port == NULL) {
+		pr_info("serial port %d not yet initialized\n", co->index);
+		return -ENODEV;
+	}
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver sprd_uart_driver;
+static struct console sprd_console = {
+	.name = SPRD_TTY_NAME,
+	.write = sprd_console_write,
+	.device = uart_console_device,
+	.setup = sprd_console_setup,
+	.flags = CON_PRINTBUFFER,
+	.index = -1,
+	.data = &sprd_uart_driver,
+};
+
+#define SPRD_CONSOLE	(&sprd_console)
+
+/* Support for earlycon */
+static void sprd_putc(struct uart_port *port, int c)
+{
+	unsigned int timeout = SPRD_TIMEOUT;
+
+	while (timeout-- &&
+		   !(readl(port->membase + SPRD_LSR) & SPRD_LSR_TX_OVER))
+		cpu_relax();
+
+	writeb(c, port->membase + SPRD_TXD);
+}
+
+static void sprd_early_write(struct console *con, const char *s,
+				    unsigned n)
+{
+	struct earlycon_device *dev = con->data;
+
+	uart_console_write(&dev->port, s, n, sprd_putc);
+}
+
+static int __init sprd_early_console_setup(
+				struct earlycon_device *device,
+				const char *opt)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	device->con->write = sprd_early_write;
+	return 0;
+}
+
+EARLYCON_DECLARE(sprd_serial, sprd_early_console_setup);
+OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart",
+		    sprd_early_console_setup);
+
+#else /* !CONFIG_SERIAL_SPRD_CONSOLE */
+#define SPRD_CONSOLE		NULL
+#endif
+
+static struct uart_driver sprd_uart_driver = {
+	.owner = THIS_MODULE,
+	.driver_name = "sprd_serial",
+	.dev_name = SPRD_TTY_NAME,
+	.major = 0,
+	.minor = 0,
+	.nr = UART_NR_MAX,
+	.cons = SPRD_CONSOLE,
+};
+
+static int sprd_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct device_node *np = pdev->dev.of_node;
+	struct uart_port *up;
+	struct clk *clk;
+	int irq;
+
+	if (np)
+		pdev->id = of_alias_get_id(np, "serial");
+
+	if (pdev->id < 0 || pdev->id >= UART_NR_MAX) {
+		dev_err(&pdev->dev, "does not support id %d\n", pdev->id);
+		return -ENXIO;
+	}
+
+	sprd_port[pdev->id] = devm_kzalloc(&pdev->dev,
+		sizeof(*sprd_port[pdev->id]), GFP_KERNEL);
+	if (!sprd_port[pdev->id])
+		return -ENOMEM;
+
+	up = &sprd_port[pdev->id]->port;
+	up->dev = &pdev->dev;
+	up->line = pdev->id;
+	up->type = PORT_SPRD;
+	up->iotype = SERIAL_IO_PORT;
+	up->uartclk = SPRD_DEF_RATE;
+	up->fifosize = SPRD_FIFO_SIZE;
+	up->ops = &serial_sprd_ops;
+	up->flags = ASYNC_BOOT_AUTOCONF;
+
+	clk = devm_clk_get(&pdev->dev, NULL);
+	if (!IS_ERR(clk))
+		up->uartclk = clk_get_rate(clk);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "not provide mem resource\n");
+		return -ENODEV;
+	}
+	up->mapbase = res->start;
+	up->membase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(up->membase))
+		return PTR_ERR(up->membase);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "not provide irq resource\n");
+		return -ENODEV;
+	}
+	up->irq = irq;
+
+	platform_set_drvdata(pdev, up);
+
+	return uart_add_one_port(&sprd_uart_driver, up);
+}
+
+static int sprd_remove(struct platform_device *dev)
+{
+	struct uart_port *up = platform_get_drvdata(dev);
+
+	return uart_remove_one_port(&sprd_uart_driver, up);
+}
+
+static int sprd_suspend(struct device *dev)
+{

drivers/tty/serial/sprd_serial.c line 705

Quoted 10 lines

drivers/tty/serial/sprd_serial.c new file +10 -0

+	int id = to_platform_device(dev)->id;
+	struct uart_port *port = &sprd_port[id]->port;
+	struct reg_backup *reg_bak = &sprd_port[id]->reg_bak;
+
+	reg_bak->ien = serial_in(port, SPRD_IEN);
+	reg_bak->ctrl0 = serial_in(port, SPRD_LCR);
+	reg_bak->ctrl1 = serial_in(port, SPRD_CTL1);
+	reg_bak->ctrl2 = serial_in(port, SPRD_CTL2);
+	reg_bak->clkd0 = serial_in(port, SPRD_CLKD0);
+	reg_bak->clkd1 = serial_in(port, SPRD_CLKD1);

Why are you saving and restoring these register states across suspend/resume?

The serial core calls your set_termios() handler upon resume (either for the console or if a tty is open) so you should be reprogramming the hardware there based on the termios settings.

Regards,
Peter Hurley

Quoted 80 lines

drivers/tty/serial/sprd_serial.c new file +67 -0

+
+	uart_suspend_port(&sprd_uart_driver, port);
+
+	return 0;
+}
+
+static int sprd_resume(struct device *dev)
+{
+	int id = to_platform_device(dev)->id;
+	struct uart_port *port = &sprd_port[id]->port;
+	struct reg_backup *reg_bak = &sprd_port[id]->reg_bak;
+
+	serial_out(port, SPRD_LCR, reg_bak->ctrl0);
+	serial_out(port, SPRD_CTL1, reg_bak->ctrl1);
+	serial_out(port, SPRD_CTL2, reg_bak->ctrl2);
+	serial_out(port, SPRD_CLKD0, reg_bak->clkd0);
+	serial_out(port, SPRD_CLKD1, reg_bak->clkd1);
+	serial_out(port, SPRD_IEN, reg_bak->ien);
+
+	uart_resume_port(&sprd_uart_driver, port);
+
+	return 0;
+}
+
+static const struct of_device_id serial_ids[] = {
+	{.compatible = "sprd,sc9836-uart",},
+	{}
+};
+
+static SIMPLE_DEV_PM_OPS(sprd_pm_ops, sprd_suspend, sprd_resume);
+
+static struct platform_driver sprd_platform_driver = {
+	.probe		= sprd_probe,
+	.remove		= sprd_remove,
+	.driver 	= {
+		.name	= "sprd_serial",
+		.of_match_table = of_match_ptr(serial_ids),
+		.pm	= &sprd_pm_ops,
+	},
+};
+
+static int __init sprd_serial_init(void)
+{
+	int ret = 0;
+
+	ret = uart_register_driver(&sprd_uart_driver);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&sprd_platform_driver);
+	if (ret)
+		uart_unregister_driver(&sprd_uart_driver);
+
+	return ret;
+}
+
+static void __exit sprd_serial_exit(void)
+{
+	platform_driver_unregister(&sprd_platform_driver);
+	uart_unregister_driver(&sprd_uart_driver);
+}
+
+module_init(sprd_serial_init);
+module_exit(sprd_serial_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Spreadtrum SoC serial driver series");

include/uapi/linux/serial_core.h +3 -0

index c172180..7e6eb39 100644
@@ -248,4 +248,7 @@
  /* MESON */
  #define PORT_MESON	109
 
+/* SPRD SERIAL  */
+#define PORT_SPRD	110
+
  #endif /* _UAPILINUX_SERIAL_CORE_H */

Hi, Peter,

Thank you for reviewing our code!
Some discussion below.

Quoted 40 lines · Peter Hurley

Quoted 5 lines · Chunyan Zhang

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

The locking doesn't look correct. Specific notations below.

Quoted 32 lines

drivers/tty/serial/sprd_serial.c new file +32 -0

+static inline void sprd_tx(int irq, void *dev_id)
+{
+    struct uart_port *port = dev_id;
+    struct circ_buf *xmit = &port->state->xmit;
+    int count;
+
+    if (port->x_char) {
+        serial_out(port, SPRD_TXD, port->x_char);
+        port->icount.tx++;
+        port->x_char = 0;
+        return;
+    }
+
+    if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+        sprd_stop_tx(port);
+        return;
+    }
+
+    count = THLD_TX_EMPTY;
+    do {
+        serial_out(port, SPRD_TXD, xmit->buf[xmit->tail]);
+        xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+        port->icount.tx++;
+        if (uart_circ_empty(xmit))
+            break;
+    } while (--count > 0);
+
+    if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+        uart_write_wakeup(port);
+
+    if (uart_circ_empty(xmit))
+        sprd_stop_tx(port);

Quoted 8 lines

drivers/tty/serial/sprd_serial.c line 284

Quoted 7 lines

drivers/tty/serial/sprd_serial.c new file +7 -0

+}
+
+/* this handles the interrupt from one port */
+static irqreturn_t sprd_handle_irq(int irq, void *dev_id)
+{
+    struct uart_port *port = (struct uart_port *)dev_id;
+    unsigned int ims;

Why does your isr not have to take port->lock ?

The original consideration is the registers are accessed by isr only. Interrupt will not be nested because of gic chip driver protection. So there is not other thread will race on it.
Does this make sense?

Quoted 17 lines

Quoted 17 lines

drivers/tty/serial/sprd_serial.c new file +16 -0

+    ims = serial_in(port, SPRD_IMSR);
+
+    if (!ims)
+        return IRQ_NONE;
+
+    serial_out(port, SPRD_ICLR, ~0);
+
+    if (ims & (SPRD_IMSR_RX_FIFO_FULL |
+        SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT))
+        sprd_rx(irq, port);
+
+    if (ims & SPRD_IMSR_TX_FIFO_EMPTY)
+        sprd_tx(irq, port);
+
+    return IRQ_HANDLED;
+}

Quoted 11 lines

Quoted 11 lines

drivers/tty/serial/sprd_serial.c new file +11 -0

+static void sprd_console_putchar(struct uart_port *port, int ch)
+{
+    wait_for_xmitr(port);
+    serial_out(port, SPRD_TXD, ch);
+}
+
+static void sprd_console_write(struct console *co, const char *s,
+                      unsigned int count)
+{
+    struct uart_port *port = &sprd_port[co->index]->port;
+    int ien;

Quoted 8 lines

drivers/tty/serial/sprd_serial.c line 532

Quoted 6 lines

drivers/tty/serial/sprd_serial.c new file +6 -0

+    int locked = 1;
+
+    if (oops_in_progress)
+        locked = spin_trylock(&port->lock);
+    else
+        spin_lock(&port->lock);

If you do need to take the port->lock in your isr, then you need to disable local irq here.

You mean to use spin_lock_irqsave()?

We do disable irq below....

Quoted 4 lines

drivers/tty/serial/sprd_serial.c line 535

Quoted 4 lines

drivers/tty/serial/sprd_serial.c new file +3 -0

+    /* save the IEN then disable the interrupts */
+    ien = serial_in(port, SPRD_IEN);
+    serial_out(port, SPRD_IEN, 0x0);

Here, we disable port IEN register.

Quoted 9 lines

Quoted 9 lines

drivers/tty/serial/sprd_serial.c new file +9 -0

+
+    uart_console_write(port, s, count, sprd_console_putchar);
+
+    /* wait for transmitter to become empty and restore the IEN */
+    wait_for_xmitr(port);
+    serial_out(port, SPRD_IEN, ien);
+    if (locked)
+        spin_unlock(&port->lock);
+}

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

Signed-off-by Chunyan Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Originally-by Lanqing Liu <[email protected]>

---
 drivers/tty/serial/Kconfig       |   18 +
 drivers/tty/serial/Makefile      |    1 +
 drivers/tty/serial/sprd_serial.c |  772 ++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/serial_core.h |    3 +
 4 files changed, 794 insertions(+)
 create mode 100644 drivers/tty/serial/sprd_serial.c

drivers/tty/serial/Kconfig +0 -0

index c79b43c..969d3cd 100644

drivers/tty/serial/Kconfig +9 -0

+       depends on SERIAL_SPRD=y
+       select SERIAL_CORE_CONSOLE
+       select SERIAL_EARLYCON
+       help
+         Support for early debug console using Spreadtrum's serial. This enables
+         the console before standard serial driver is probed. This is enabled
+         with "earlycon" on the kernel command line. The console is
+         enabled when early_param is processed.
+
 endmenu
 
 config SERIAL_MCTRL_GPIO

drivers/tty/serial/Makefile +1 -0

index 9a548ac..4801aca 100644
@@ -93,6 +93,7 @@ obj-$(CONFIG_SERIAL_ARC)      += arc_uart.o
 obj-$(CONFIG_SERIAL_RP2)       += rp2.o
 obj-$(CONFIG_SERIAL_FSL_LPUART)        += fsl_lpuart.o
 obj-$(CONFIG_SERIAL_MEN_Z135)  += men_z135_uart.o
+obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
 
 # GPIOLIB helpers for modem control lines
 obj-$(CONFIG_SERIAL_MCTRL_GPIO)        += serial_mctrl_gpio.o

drivers/tty/serial/sprd_serial.c new file +0 -0

new file mode 100644
index 0000000..81839e4

drivers/tty/serial/sprd_serial.c new file +19 -0

+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>

drivers/tty/serial/sprd_serial.c new file +5 -0

+static struct platform_driver sprd_platform_driver = {
+       .probe          = sprd_probe,
+       .remove         = sprd_remove,
+       .driver         = {
+               .name   = "sprd_serial",

Quoted 25 lines · Chunyan Zhang

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

Signed-off-by Chunyan Zhang <[email protected]>

Signed-off-by Orson Zhai <[email protected]>

Originally-by Lanqing Liu <[email protected]>

---
 drivers/tty/serial/Kconfig       |   18 +
 drivers/tty/serial/Makefile      |    1 +
 drivers/tty/serial/sprd_serial.c |  772 ++++++++++++++++++++++++++++++++++++++
 include/uapi/linux/serial_core.h |    3 +
 4 files changed, 794 insertions(+)
 create mode 100644 drivers/tty/serial/sprd_serial.c

drivers/tty/serial/Kconfig +0 -0

index c79b43c..969d3cd 100644
@@ -1577,6 +1577,24 @@ config SERIAL_MEN_Z135
          This driver can also be build as a module. If so, the module will be called
          men_z135_uart.ko
 

drivers/tty/serial/Kconfig config SERIAL_MEN_Z135 · line 1581

Quoted 2 lines

drivers/tty/serial/Kconfig +2 -0

+config SERIAL_SPRD
+       tristate "Support for SPRD serial"

Can the menu text spell out Spreadtrum. What SPRD means is not obvious.

drivers/tty/serial/Kconfig config SERIAL_MEN_Z135 · line 1588

Quoted 7 lines

drivers/tty/serial/Kconfig +7 -0

+       depends on ARCH_SPRD
+       select SERIAL_CORE
+       help
+         This enables the driver for the Spreadtrum's serial.
+
+config SERIAL_SPRD_CONSOLE
+       bool "SPRD UART console support"

Same here.

Quoted 22 lines

drivers/tty/serial/Kconfig +9 -0

+       depends on SERIAL_SPRD=y
+       select SERIAL_CORE_CONSOLE
+       select SERIAL_EARLYCON
+       help
+         Support for early debug console using Spreadtrum's serial. This enables
+         the console before standard serial driver is probed. This is enabled
+         with "earlycon" on the kernel command line. The console is
+         enabled when early_param is processed.
+
 endmenu
 
 config SERIAL_MCTRL_GPIO

drivers/tty/serial/Makefile +1 -0

index 9a548ac..4801aca 100644
@@ -93,6 +93,7 @@ obj-$(CONFIG_SERIAL_ARC)      += arc_uart.o
 obj-$(CONFIG_SERIAL_RP2)       += rp2.o
 obj-$(CONFIG_SERIAL_FSL_LPUART)        += fsl_lpuart.o
 obj-$(CONFIG_SERIAL_MEN_Z135)  += men_z135_uart.o
+obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
 

drivers/tty/serial/sprd_serial.c line 2

Quoted 10 lines

drivers/tty/serial/Makefile +0 -0

 # GPIOLIB helpers for modem control lines
 obj-$(CONFIG_SERIAL_MCTRL_GPIO)        += serial_mctrl_gpio.o

drivers/tty/serial/sprd_serial.c new file +2 -0

new file mode 100644
index 0000000..81839e4
@@ -0,0 +1,772 @@
+/*
+ * Copyright (C) 2012 Spreadtrum Communications Inc.

This is unchanged in 3 years?

Quoted 26 lines

drivers/tty/serial/sprd_serial.c new file +26 -0

+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+

drivers/tty/serial/sprd_serial.c line 31

Quoted 3 lines

drivers/tty/serial/sprd_serial.c new file +3 -0

+/* device name */
+#define UART_NR_MAX            8
+#define SPRD_TTY_NAME          "ttySPX"

We really want to get away from per SOC serial names and use ttyS for serial port /dev names. There's issues switching existing drivers because this creates an ABI, so we can only have new drivers follow this.

[...]

Quoted 9 lines

drivers/tty/serial/sprd_serial.c new file +9 -0

+static struct platform_driver sprd_platform_driver = {
+       .probe          = sprd_probe,
+       .remove         = sprd_remove,
+       .driver         = {
+               .name   = "sprd_serial",
+               .of_match_table = of_match_ptr(serial_ids),
+               .pm     = &sprd_pm_ops,
+       },
+};

drivers/tty/serial/sprd_serial.c line 751

Quoted 6 lines

drivers/tty/serial/sprd_serial.c new file +6 -0

+
+static int __init sprd_serial_init(void)
+{
+       int ret = 0;
+
+       ret = uart_register_driver(&sprd_uart_driver);

This can be done in probe now. Then you can use module_platform_driver().

Rob

Quoted 7 lines · Rob Herring

Quoted 5 lines · Chunyan Zhang

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

Quoted 8 lines

drivers/tty/serial/sprd_serial.c line 751

Quoted 5 lines

drivers/tty/serial/sprd_serial.c new file +5 -0

+static int __init sprd_serial_init(void)
+{
+       int ret = 0;
+
+       ret = uart_register_driver(&sprd_uart_driver);

This can be done in probe now. Then you can use module_platform_driver().

Question:
1. there are 4 uart ports configured in dt for sprd_serial, so probe will be called 4 times, but uart_register_driver only needs to be called one time, so can we use uart_driver.state to check if uart_register_driver has already been called ?

2. if I use module_platform_driver() instead of module_init(sprd_serial_init) and module_exit(sprd_serial_exit) , I must move uart_unregister_driver() which is now processed in sprd_serial_exit() to sprd_remove(), there is a similar problem with probe(), sprd_remove() will also be called 4 times, and actually it should be called only one time. How can we deal with this case?

3. for the second question, we can check the platform_device->id, if it is equal to the index of last port (e.g. 4 for this case), then uart_unregister_driver() can be called. Does it work correctly? since for this case, we must keep the order of releasing ports.

Quoted 8 lines · Lyra Zhang

Quoted 7 lines · Rob Herring

Quoted 5 lines · Chunyan Zhang

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

[...]

Quoted 9 lines

Quoted 8 lines

drivers/tty/serial/sprd_serial.c line 751

Quoted 5 lines

drivers/tty/serial/sprd_serial.c new file +5 -0

+static int __init sprd_serial_init(void)
+{
+       int ret = 0;
+
+       ret = uart_register_driver(&sprd_uart_driver);

This can be done in probe now. Then you can use module_platform_driver().

Quoted 5 lines

Question:
1. there are 4 uart ports configured in dt for sprd_serial, so probe will be called 4 times, but uart_register_driver only needs to be called one time, so can we use uart_driver.state to check if uart_register_driver has already been called ?

Yes.

Quoted 6 lines

2. if I use module_platform_driver() instead of module_init(sprd_serial_init) and module_exit(sprd_serial_exit) , I must move uart_unregister_driver() which is now processed in sprd_serial_exit() to sprd_remove(), there is a similar problem with probe(), sprd_remove() will also be called 4 times, and actually it should be called only one time. How can we deal with this case?

Look at pl01x or Samsung UART drivers which have done this conversion.

Quoted 5 lines

3. for the second question, we can check the platform_device->id, if it is equal to the index of last port (e.g. 4 for this case), then uart_unregister_driver() can be called. Does it work correctly? since for this case, we must keep the order of releasing ports.

The id will not be the line index in the DT case. I don't think you can guarantee the order either.

It would be better to make uart_{un}register_driver deal with being called multiple times so drivers don't have to deal with getting this correct. I'm not sure if that is feasible though.

Rob

Hi, Rob

I still have a question to be conform, specific describes below:

Quoted 29 lines · Rob Herring

Quoted 8 lines · Lyra Zhang

Quoted 7 lines · Rob Herring

Quoted 5 lines · Chunyan Zhang

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

[...]

Quoted 9 lines

Quoted 8 lines

drivers/tty/serial/sprd_serial.c line 751

Quoted 5 lines

drivers/tty/serial/sprd_serial.c new file +5 -0

+static int __init sprd_serial_init(void)
+{
+       int ret = 0;
+
+       ret = uart_register_driver(&sprd_uart_driver);

This can be done in probe now. Then you can use module_platform_driver().

Quoted 5 lines

Question:
1. there are 4 uart ports configured in dt for sprd_serial, so probe will be called 4 times, but uart_register_driver only needs to be called one time, so can we use uart_driver.state to check if uart_register_driver has already been called ?

Yes.

Quoted 8 lines

Quoted 6 lines

2. if I use module_platform_driver() instead of module_init(sprd_serial_init) and module_exit(sprd_serial_exit) , I must move uart_unregister_driver() which is now processed in sprd_serial_exit() to sprd_remove(), there is a similar problem with probe(), sprd_remove() will also be called 4 times, and actually it should be called only one time. How can we deal with this case?

Look at pl01x or Samsung UART drivers which have done this conversion.

Samsung UART does use module_platform_driver, but pl010/pl011 doesn't. In the Samsung UART driver, uart_unregister_driver is processed in remove(), like below:

static int s3c24xx_serial_remove(struct platform_device *dev)

{
    struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);

    if (port) {
        s3c24xx_serial_cpufreq_deregister(to_ourport(port));
        uart_remove_one_port(&s3c24xx_uart_drv, port);
    }

    uart_unregister_driver(&s3c24xx_uart_drv);
}

if this serial has more than one ports, uart_unregister_driver() must be called multiple times when the device need to be removed. I think there may be a problem because that uart_unregister_driver() will do kfree(drv->state) every time when it's called.

Thanks,
Chunyan

Quoted 14 lines

Quoted 5 lines

3. for the second question, we can check the platform_device->id, if it is equal to the index of last port (e.g. 4 for this case), then uart_unregister_driver() can be called. Does it work correctly? since for this case, we must keep the order of releasing ports.

The id will not be the line index in the DT case. I don't think you can guarantee the order either.

It would be better to make uart_{un}register_driver deal with being called multiple times so drivers don't have to deal with getting this correct. I'm not sure if that is feasible though.

Rob

Hi, Rob

I still have a question to be conform, specific describes below:

Quoted 36 lines · Rob Herring

Quoted 8 lines · Lyra Zhang

Quoted 7 lines · Rob Herring

Quoted 5 lines · Chunyan Zhang

Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform.
This driver also support earlycon.
This patch also replaced the spaces between the macros and their values with the tabs in serial_core.h

[...]

Quoted 9 lines

Quoted 8 lines

drivers/tty/serial/sprd_serial.c line 751

Quoted 5 lines

drivers/tty/serial/sprd_serial.c new file +5 -0

+static int __init sprd_serial_init(void)
+{
+       int ret = 0;
+
+       ret = uart_register_driver(&sprd_uart_driver);

This can be done in probe now. Then you can use module_platform_driver().

Quoted 5 lines

Question:
1. there are 4 uart ports configured in dt for sprd_serial, so probe will be called 4 times, but uart_register_driver only needs to be called one time, so can we use uart_driver.state to check if uart_register_driver has already been called ?

Yes.

Quoted 6 lines

2. if I use module_platform_driver() instead of module_init(sprd_serial_init) and module_exit(sprd_serial_exit) , I must move uart_unregister_driver() which is now processed in sprd_serial_exit() to sprd_remove(), there is a similar problem with probe(), sprd_remove() will also be called 4 times, and actually it should be called only one time. How can we deal with this case?

Quoted 1 line

Look at pl01x or Samsung UART drivers which have done this conversion.

Samsung UART does use module_platform_driver, but pl010/pl011 doesn't.

In the Samsung UART driver, uart_unregister_driver is processed in remove(), like below:

static int s3c24xx_serial_remove(struct platform_device *dev)

{
    struct uart_port *port = s3c24xx_dev_to_port(&dev->dev);

    if (port) {
        s3c24xx_serial_cpufreq_deregister(to_ourport(port));
        uart_remove_one_port(&s3c24xx_uart_drv, port);
    }

    uart_unregister_driver(&s3c24xx_uart_drv);
}

if this serial has more than one ports, uart_unregister_driver() must be called multiple times when the device need to be removed. I think there may be a problem because that uart_unregister_driver() will do kfree(drv->state) every time when it's called.