drivers: timer: inroduce ARC timer driver

This patch series replaces legacy approach to access ARC timer via specific code in "arch/arc/lib/time.c" and uses timer driver instead.

ARC cores may have up to 2 built-in timers: timer0 and timer1, usually at least one of them exists.

They are controlled through auxiliary registers and so we don't have to remap their control registers as we used to do with MMIO registers of external peripheral devices.

---
Changes v1..v2
- Minor clean-ups of code and comments.
- Moved TIMER and ARC_TIMER config symbols from each defconfig to
arch Kconfig file to avoid duplication

Vlad Zakharov (2):
drivers: timer: Introduce ARC timer driver
arc: use timer driver instead of arch/arc/lib/timer.c

 arch/arc/dts/skeleton.dtsi                   |  6 ++
 arch/arc/include/asm/arcregs.h               |  4 ++
 arch/arc/lib/Makefile                        |  1 -
 arch/arc/lib/timer.c                         | 24 -------
 configs/axs101_defconfig                     |  2 +
 configs/axs103_defconfig                     |  2 +
 configs/nsim_700_defconfig                   |  2 +
 configs/nsim_700be_defconfig                 |  2 +
 configs/nsim_hs38_defconfig                  |  2 +
 configs/nsim_hs38be_defconfig                |  2 +
 configs/tb100_defconfig                      |  2 +
 doc/device-tree-bindings/timer/arc_timer.txt | 24 +++++++
 drivers/timer/Kconfig                        |  7 ++
 drivers/timer/Makefile                       |  1 +
 drivers/timer/arc_timer.c                    | 95 ++++++++++++++++++++++++++++
 include/configs/axs10x.h                     |  2 -
 16 files changed, 151 insertions(+), 27 deletions(-)
 delete mode 100644 arch/arc/lib/timer.c
 create mode 100644 doc/device-tree-bindings/timer/arc_timer.txt
 create mode 100644 drivers/timer/arc_timer.c

2.7.4

This commit introduces timer driver for ARC.

ARC timers are configured via ARC AUX registers so we use special functions to access timer control registers.

This driver allows utilization of either timer0 or timer1 depending on which one is available in real hardware. Essentially only existing timers should be mentioned in board's Device Tree description.

---
Changes v1..v2
- Minor clean-ups of code and comments

 arch/arc/include/asm/arcregs.h               |  4 ++
 doc/device-tree-bindings/timer/arc_timer.txt | 24 +++++++
 drivers/timer/Kconfig                        | 10 +++
 drivers/timer/Makefile                       |  1 +
 drivers/timer/arc_timer.c                    | 99 ++++++++++++++++++++++++++++
 5 files changed, 138 insertions(+)
 create mode 100644 doc/device-tree-bindings/timer/arc_timer.txt
 create mode 100644 drivers/timer/arc_timer.c

index cf999b0..54a9b00 100644
@@ -33,6 +33,10 @@
 #define ARC_AUX_TIMER0_CTRL	0x22	/* Timer 0 control */
 #define ARC_AUX_TIMER0_LIMIT	0x23	/* Timer 0 limit */
 
+#define ARC_AUX_TIMER1_CNT	0x100	/* Timer 1 count */
+#define ARC_AUX_TIMER1_CTRL	0x101	/* Timer 1 control */
+#define ARC_AUX_TIMER1_LIMIT	0x102	/* Timer 1 limit */
+
 #define ARC_AUX_INTR_VEC_BASE	0x25
 
 /* Data cache related auxiliary registers */

new file mode 100644
index 0000000..e25c6ae
@@ -0,0 +1,24 @@
+ARC Timer
+
+Required properties:
+
+- compatible : should be "snps,arc-timer"
+- reg : Specifies timer ID, could be either 0 or 1.
+- clock-frequency : The frequency of the clock that drives the counter, in Hz.
+
+Examples:
+
+timer at 0 {
+	compatible = "snps,arc-timer";
+	clock-frequency = <100000000>;
+	reg = <0>;
+};
+
+timer at 1 {
+	compatible = "snps,arc-timer";
+	clock-frequency = <100000000>;
+	reg = <1>;
+};
+
+NOTE: if you specify both timers, frequencies should always be the same as both timers
+are driven by core clock.

index cb18f12..e1e3e61 100644
@@ -46,4 +46,14 @@ config OMAP_TIMER
 	help
 	  Select this to enable an timer for Omap devices.
 
+config ARC_TIMER
+	bool "ARC timer support"
+	depends on TIMER
+	depends on ARC
+	help
+	  Select this to enable built-in ARC timers.
+	  ARC cores may have up to 2 built-in timers: timer0 and timer1,
+	  usually at least one of them exists. Either of them is supported
+	  in U-Boot.
+
 endmenu

index f351fbb..e9624dd 100644
@@ -9,3 +9,4 @@ obj-$(CONFIG_ALTERA_TIMER)	+= altera_timer.o
 obj-$(CONFIG_SANDBOX_TIMER)	+= sandbox_timer.o
 obj-$(CONFIG_X86_TSC_TIMER)	+= tsc_timer.o
 obj-$(CONFIG_OMAP_TIMER)	+= omap-timer.o
+obj-$(CONFIG_ARC_TIMER)	+= arc_timer.o

2.7.4

This commit replaces legacy timer code with usage of arc timer driver.

Also it adds timer0 device tree node with corresponding "clock-frequency" property.

Therefore we remove legacy CONFIG_SYS_TIMER_RATE config symbol that is not longer required.

Furthermore the commit selects CONFIG_TIMER and CONFIG_ARC_TIMER by default when selecting ARC architecture.

---
Changes v1..v2
- Moved TIMER and ARC_TIMER config symbols from each defconfig to
arch Kconfig file to avoid duplication

 arch/Kconfig               |  2 ++
 arch/arc/dts/skeleton.dtsi |  6 ++++++
 arch/arc/lib/Makefile      |  1 -
 arch/arc/lib/timer.c       | 24 ------------------------
 include/configs/axs10x.h   |  2 --
 5 files changed, 8 insertions(+), 27 deletions(-)
 delete mode 100644 arch/arc/lib/timer.c

index ffc7b45..56fa70e 100644
@@ -12,6 +12,8 @@ config ARC
 	bool "ARC architecture"
 	select HAVE_PRIVATE_LIBGCC
 	select SUPPORT_OF_CONTROL
+	select TIMER
+	select ARC_TIMER
 
 config ARM
 	bool "ARM architecture"

index b41d241..3e93d697 100644
@@ -10,4 +10,10 @@
 	chosen { };
 	aliases { };
 	memory { device_type = "memory"; reg = <0 0>; };
+
+	timer at 0 {
+			compatible = "snps,arc-timer";
+			clock-frequency = <100000000>;
+			reg = <0>;
+	};
 };

index eb62b3c..12097bf 100644
@@ -18,7 +18,6 @@ obj-y += memcmp.o
 obj-y += memcpy-700.o
 obj-y += memset.o
 obj-y += reset.o
-obj-y += timer.o
 obj-y += ints_low.o
 obj-y += init_helpers.o
 

deleted file mode 100644
index a0acbbc..0000000
@@ -1,24 +0,0 @@
-/*
- * Copyright (C) 2013-2014 Synopsys, Inc. All rights reserved.
- *
- * SPDX-License-Identifier:	GPL-2.0+
- */
-
-#include <asm/arcregs.h>
-
-#define NH_MODE	(1 << 1)	/* Disable timer if CPU is halted */
-
-int timer_init(void)
-{
-	write_aux_reg(ARC_AUX_TIMER0_CTRL, NH_MODE);
-	/* Set max value for counter/timer */
-	write_aux_reg(ARC_AUX_TIMER0_LIMIT, 0xffffffff);
-	/* Set initial count value and restart counter/timer */
-	write_aux_reg(ARC_AUX_TIMER0_CNT, 0);
-	return 0;
-}
-
-unsigned long timer_read_counter(void)
-{
-	return read_aux_reg(ARC_AUX_TIMER0_CNT);
-}

index 3546c8d..0476223 100644
@@ -11,8 +11,6 @@
 /*
  *  CPU configuration
  */
-#define CONFIG_SYS_TIMER_RATE		CONFIG_SYS_CLK_FREQ
-
 #define ARC_FPGA_PERIPHERAL_BASE	0xE0000000
 #define ARC_APB_PERIPHERAL_BASE		0xF0000000
 #define ARC_DWMMC_BASE			(ARC_FPGA_PERIPHERAL_BASE + 0x15000)

2.7.4

Hi Tom, Simon,

I'm wondering if you guys would like to accept this short series in your tree or I may apply it on mine and send pull-request to Tom later on?

-Alexey

Tom, Simon,

Opps, there's actually v3 already, pls refer to it here:
http://patchwork.ozlabs.org/patch/696114/
http://patchwork.ozlabs.org/patch/696115/

And sorry for the noise!
Thanks to Vlad for catching this SNAFU.

-Alexey

FWIW, I have these assigned to you in patchwork as I figured they would come via the arc tree, thanks!

Tom
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Hi Tom,

See that's the first day after the weekend and I'm still thinking about everything but work... that said I noticed you're a delegate for another Vlad's patch and somehow decided you're the guys for all Vlad's patches :)

I'll apply this series to my tree and some other patches as well and will send a pull-request shortly.

Hope to not mess things another time around... but cannot promise really :(

-Alexey