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ARM: debug: add support for Palmchip 16550-like UART

PATCH RESEND Superseded Mans Rullgard 3 participants 7 messages Oct 27, 2015 – Nov 4, 2015

Subsystems (2)
Arm (32-bit) TTY layer and serial drivers

v1 of 2 Superseded Latest is v2 →

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Mans Rullgard

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#0 lore raw

PATCH RESEND 1/1 ARM: debug: add support for Palmchip 16550-like UART

Some SoCs have a Palmchip UART with a non-standard register layout. This allows the debug console to work with these.

Signed-off-by Mans Rullgard <[email protected]>
---
 arch/arm/Kconfig.debug        |  8 ++++++++
 arch/arm/include/debug/8250.S | 12 ++++++++++++
 2 files changed, 20 insertions(+)
arch/arm/Kconfig.debug +8 -0
index 0cfd7f9..9039fff 100644
@@ -1597,6 +1597,14 @@ config DEBUG_UART_8250_WORD
 		DEBUG_BCM_KONA_UART || DEBUG_RK32_UART2 || \
 		DEBUG_BRCMSTB_UART
 
+config DEBUG_UART_8250_PALMCHIP
+	bool "8250 UART is Palmchip variant"
+	depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250
+	help
+	  Palmchip provides a UART implementation compatible with 16550
+	  except for having a different register layout.  Say Y here if
+	  the debug UART is of this type.
+
 config DEBUG_UART_8250_FLOW_CONTROL
 	bool "Enable flow control for 8250 UART"
 	depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250
arch/arm/include/debug/8250.S +12 -0
index 7f7446f..2332f40 100644
@@ -9,6 +9,18 @@
  */
 #include <linux/serial_reg.h>
 
+#ifdef CONFIG_DEBUG_UART_8250_PALMCHIP
+
+#undef UART_TX
+#undef UART_LSR
+#undef UART_MSR
+
+#define UART_TX 1
+#define UART_LSR 7
+#define UART_MSR 8
+
+#endif
+
 		.macro	addruart, rp, rv, tmp
 		ldr	\rp, =CONFIG_DEBUG_UART_PHYS
 		ldr	\rv, =CONFIG_DEBUG_UART_VIRT
Signature · 1 line
2.6.2
#1 lore raw

PATCH RESEND 1/1 ARM: debug: add support for Palmchip 16550-like UART

Quoted 14 lines · Mans Rullgard

Some SoCs have a Palmchip UART with a non-standard register layout. This allows the debug console to work with these.

Signed-off-by Mans Rullgard <[email protected]>
---
 arch/arm/Kconfig.debug        |  8 ++++++++
 arch/arm/include/debug/8250.S | 12 ++++++++++++
 2 files changed, 20 insertions(+)
arch/arm/Kconfig.debug +0 -0
index 0cfd7f9..9039fff 100644

arch/arm/Kconfig.debug config DEBUG_UART_8250_WORD · line 1602

Quoted 6 lines
arch/arm/Kconfig.debug +3 -0
@@ -1597,6 +1597,14 @@ config DEBUG_UART_8250_WORD
 		DEBUG_BCM_KONA_UART || DEBUG_RK32_UART2 || \
 		DEBUG_BRCMSTB_UART
 
+config DEBUG_UART_8250_PALMCHIP
+	bool "8250 UART is Palmchip variant"
+	depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250

I am 100% clueless about the UART sequence in Linux.

There's earlyprintk, the boot console (polled?), the "full-blown" console (with IRQs)...

If I want earlyprintk, I have to enable DEBUG_LL (?) so I'll have DEBUG_LL_UART_8250, right? There's no way to pick DEBUG_UART_8250 in menuconfig, is there?

So I picked the following options:

CONFIG_DEBUG_LL=y
# CONFIG_DEBUG_ICEDCC is not set
# CONFIG_DEBUG_SEMIHOSTING is not set
CONFIG_DEBUG_LL_UART_8250=y
# CONFIG_DEBUG_LL_UART_PL01X is not set
CONFIG_DEBUG_LL_INCLUDE="debug/8250.S"
# CONFIG_DEBUG_UART_8250 is not set
# CONFIG_DEBUG_UART_BCM63XX is not set
CONFIG_DEBUG_UART_PHYS=0x10700
CONFIG_DEBUG_UART_VIRT=0xf0010700
CONFIG_DEBUG_UART_8250_SHIFT=2
CONFIG_DEBUG_UART_8250_WORD=y
CONFIG_DEBUG_UART_8250_PALMCHIP=y
# CONFIG_DEBUG_UART_8250_FLOW_CONTROL is not set
CONFIG_DEBUG_UNCOMPRESS=y
CONFIG_UNCOMPRESS_INCLUDE="debug/uncompress.h"
CONFIG_EARLY_PRINTK=y

I suppose I have to provide DEBUG_UART_PHYS because it needs the address before it can parse the DT? But how am I supposed to know the virtual address? Isn't that from iomap(UART_PHYS)?

'make' wouldn't let me proceed unless I gave something...

Then I have to add earlyprintk to my boot command line, right? Do I need to specify more than that?
According to the documentation,

	earlyprintk=	[X86,SH,BLACKFIN,ARM,M68k]
			earlyprintk=vga
			earlyprintk=efi
			earlyprintk=xen
			earlyprintk=serial[,ttySn[,baudrate]]
			earlyprintk=serial[,0x...[,baudrate]]
			earlyprintk=ttySn[,baudrate]
			earlyprintk=dbgp[debugController#]
			earlyprintk=pciserial,bus:device.function[,baudrate]
Quoted 22 lines
arch/arm/Kconfig.debug +5 -0
+	help
+	  Palmchip provides a UART implementation compatible with 16550
+	  except for having a different register layout.  Say Y here if
+	  the debug UART is of this type.
+
 config DEBUG_UART_8250_FLOW_CONTROL
 	bool "Enable flow control for 8250 UART"
 	depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250
arch/arm/include/debug/8250.S +5 -0
index 7f7446f..2332f40 100644
@@ -9,6 +9,18 @@
  */
 #include <linux/serial_reg.h>
 
+#ifdef CONFIG_DEBUG_UART_8250_PALMCHIP
+
+#undef UART_TX
+#undef UART_LSR
+#undef UART_MSR

arch/arm/include/debug/8250.S line 26

Quoted 10 lines
arch/arm/include/debug/8250.S +7 -0
+
+#define UART_TX 1
+#define UART_LSR 7
+#define UART_MSR 8
+
+#endif
+
 		.macro	addruart, rp, rv, tmp
 		ldr	\rp, =CONFIG_DEBUG_UART_PHYS
 		ldr	\rv, =CONFIG_DEBUG_UART_VIRT

Regards.

author
#2 lore raw

PATCH RESEND 1/1 ARM: debug: add support for Palmchip 16550-like UART

Quoted 43 lines · Mason
Quoted 14 lines · Mans Rullgard

Some SoCs have a Palmchip UART with a non-standard register layout. This allows the debug console to work with these.

Signed-off-by Mans Rullgard <[email protected]>
---
 arch/arm/Kconfig.debug        |  8 ++++++++
 arch/arm/include/debug/8250.S | 12 ++++++++++++
 2 files changed, 20 insertions(+)
arch/arm/Kconfig.debug +0 -0
index 0cfd7f9..9039fff 100644

arch/arm/Kconfig.debug config DEBUG_UART_8250_WORD · line 1602

Quoted 6 lines
arch/arm/Kconfig.debug +3 -0
@@ -1597,6 +1597,14 @@ config DEBUG_UART_8250_WORD
 		DEBUG_BCM_KONA_UART || DEBUG_RK32_UART2 || \
 		DEBUG_BRCMSTB_UART
 
+config DEBUG_UART_8250_PALMCHIP
+	bool "8250 UART is Palmchip variant"
+	depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250

I am 100% clueless about the UART sequence in Linux.

There's earlyprintk, the boot console (polled?), the "full-blown" console (with IRQs)...

If I want earlyprintk, I have to enable DEBUG_LL (?) so I'll have DEBUG_LL_UART_8250, right? There's no way to pick DEBUG_UART_8250 in menuconfig, is there?

So I picked the following options:

CONFIG_DEBUG_LL=y
# CONFIG_DEBUG_ICEDCC is not set
# CONFIG_DEBUG_SEMIHOSTING is not set
CONFIG_DEBUG_LL_UART_8250=y
# CONFIG_DEBUG_LL_UART_PL01X is not set
CONFIG_DEBUG_LL_INCLUDE="debug/8250.S"
# CONFIG_DEBUG_UART_8250 is not set
# CONFIG_DEBUG_UART_BCM63XX is not set
CONFIG_DEBUG_UART_PHYS=0x10700

Quoted 8 lines

CONFIG_DEBUG_UART_VIRT=0xf0010700
CONFIG_DEBUG_UART_8250_SHIFT=2
CONFIG_DEBUG_UART_8250_WORD=y
CONFIG_DEBUG_UART_8250_PALMCHIP=y
# CONFIG_DEBUG_UART_8250_FLOW_CONTROL is not set
CONFIG_DEBUG_UNCOMPRESS=y
CONFIG_UNCOMPRESS_INCLUDE="debug/uncompress.h"
CONFIG_EARLY_PRINTK=y

Those are the settings I use.

Quoted 3 lines

I suppose I have to provide DEBUG_UART_PHYS because it needs the address before it can parse the DT? But how am I supposed to know the virtual address? Isn't that from iomap(UART_PHYS)?

The decompression code and early setup don't have that luxury.

Quoted 4 lines

'make' wouldn't let me proceed unless I gave something...

Then I have to add earlyprintk to my boot command line, right? Do I need to specify more than that?

Just earlyprintk without any parameters works.

Signature · 2 lines
M?ns Rullg?rd
mans at mansr.com
#3 lore raw

PATCH RESEND 1/1 ARM: debug: add support for Palmchip 16550-like UART

Quoted 54 lines · M?ns Rullg?rd
Quoted 43 lines · Mason
Quoted 14 lines · Mans Rullgard

Some SoCs have a Palmchip UART with a non-standard register layout. This allows the debug console to work with these.

Signed-off-by Mans Rullgard <[email protected]>
---
 arch/arm/Kconfig.debug        |  8 ++++++++
 arch/arm/include/debug/8250.S | 12 ++++++++++++
 2 files changed, 20 insertions(+)
arch/arm/Kconfig.debug +0 -0
index 0cfd7f9..9039fff 100644

arch/arm/Kconfig.debug config DEBUG_UART_8250_WORD · line 1602

Quoted 6 lines
arch/arm/Kconfig.debug +3 -0
@@ -1597,6 +1597,14 @@ config DEBUG_UART_8250_WORD
 		DEBUG_BCM_KONA_UART || DEBUG_RK32_UART2 || \
 		DEBUG_BRCMSTB_UART
 
+config DEBUG_UART_8250_PALMCHIP
+	bool "8250 UART is Palmchip variant"
+	depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250

I am 100% clueless about the UART sequence in Linux.

There's earlyprintk, the boot console (polled?), the "full-blown" console (with IRQs)...

If I want earlyprintk, I have to enable DEBUG_LL (?) so I'll have DEBUG_LL_UART_8250, right? There's no way to pick DEBUG_UART_8250 in menuconfig, is there?

So I picked the following options:

CONFIG_DEBUG_LL=y
# CONFIG_DEBUG_ICEDCC is not set
# CONFIG_DEBUG_SEMIHOSTING is not set
CONFIG_DEBUG_LL_UART_8250=y
# CONFIG_DEBUG_LL_UART_PL01X is not set
CONFIG_DEBUG_LL_INCLUDE="debug/8250.S"
# CONFIG_DEBUG_UART_8250 is not set
# CONFIG_DEBUG_UART_BCM63XX is not set
CONFIG_DEBUG_UART_PHYS=0x10700

Quoted 8 lines

CONFIG_DEBUG_UART_VIRT=0xf0010700
CONFIG_DEBUG_UART_8250_SHIFT=2
CONFIG_DEBUG_UART_8250_WORD=y
CONFIG_DEBUG_UART_8250_PALMCHIP=y
# CONFIG_DEBUG_UART_8250_FLOW_CONTROL is not set
CONFIG_DEBUG_UNCOMPRESS=y
CONFIG_UNCOMPRESS_INCLUDE="debug/uncompress.h"
CONFIG_EARLY_PRINTK=y

Quoted 7 lines

Those are the settings I use.

Quoted 3 lines

I suppose I have to provide DEBUG_UART_PHYS because it needs the address before it can parse the DT? But how am I supposed to know the virtual address? Isn't that from iomap(UART_PHYS)?

The decompression code and early setup don't have that luxury.

But how am I supposed to compute the virtual address? Can I set DEBUG_UART_VIRT to 0xdeadbeef? :-)

Also is it expected that setting DEBUG_LL forces make to recompile every source file in the source tree?

Regards.

author
#4 lore raw

PATCH RESEND 1/1 ARM: debug: add support for Palmchip 16550-like UART

Quoted 58 lines · Mason
Quoted 56 lines · M?ns Rullg?rd
Quoted 43 lines · Mason
Quoted 14 lines · Mans Rullgard

Some SoCs have a Palmchip UART with a non-standard register layout. This allows the debug console to work with these.

Signed-off-by Mans Rullgard <[email protected]>
---
 arch/arm/Kconfig.debug        |  8 ++++++++
 arch/arm/include/debug/8250.S | 12 ++++++++++++
 2 files changed, 20 insertions(+)
arch/arm/Kconfig.debug +0 -0
index 0cfd7f9..9039fff 100644

arch/arm/Kconfig.debug config DEBUG_UART_8250_WORD · line 1602

Quoted 6 lines
arch/arm/Kconfig.debug +3 -0
@@ -1597,6 +1597,14 @@ config DEBUG_UART_8250_WORD
 		DEBUG_BCM_KONA_UART || DEBUG_RK32_UART2 || \
 		DEBUG_BRCMSTB_UART
 
+config DEBUG_UART_8250_PALMCHIP
+	bool "8250 UART is Palmchip variant"
+	depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250

I am 100% clueless about the UART sequence in Linux.

There's earlyprintk, the boot console (polled?), the "full-blown" console (with IRQs)...

If I want earlyprintk, I have to enable DEBUG_LL (?) so I'll have DEBUG_LL_UART_8250, right? There's no way to pick DEBUG_UART_8250 in menuconfig, is there?

So I picked the following options:

CONFIG_DEBUG_LL=y
# CONFIG_DEBUG_ICEDCC is not set
# CONFIG_DEBUG_SEMIHOSTING is not set
CONFIG_DEBUG_LL_UART_8250=y
# CONFIG_DEBUG_LL_UART_PL01X is not set
CONFIG_DEBUG_LL_INCLUDE="debug/8250.S"
# CONFIG_DEBUG_UART_8250 is not set
# CONFIG_DEBUG_UART_BCM63XX is not set
CONFIG_DEBUG_UART_PHYS=0x10700

Quoted 8 lines

CONFIG_DEBUG_UART_VIRT=0xf0010700
CONFIG_DEBUG_UART_8250_SHIFT=2
CONFIG_DEBUG_UART_8250_WORD=y
CONFIG_DEBUG_UART_8250_PALMCHIP=y
# CONFIG_DEBUG_UART_8250_FLOW_CONTROL is not set
CONFIG_DEBUG_UNCOMPRESS=y
CONFIG_UNCOMPRESS_INCLUDE="debug/uncompress.h"
CONFIG_EARLY_PRINTK=y

Those are the settings I use.

Quoted 8 lines
Quoted 5 lines
Quoted 3 lines

I suppose I have to provide DEBUG_UART_PHYS because it needs the address before it can parse the DT? But how am I supposed to know the virtual address? Isn't that from iomap(UART_PHYS)?

The decompression code and early setup don't have that luxury.

But how am I supposed to compute the virtual address? Can I set DEBUG_UART_VIRT to 0xdeadbeef? :-)

Add 0xf0000000.

Quoted 2 lines

Also is it expected that setting DEBUG_LL forces make to recompile every source file in the source tree?

Apparently. :)

Signature · 2 lines
M?ns Rullg?rd
mans at mansr.com
#5 lore raw
In reply to Mans Rullgard
Quoted 8 lines · On Tuesday 27 October 2015 12:57:57 Mans Rullgard wrote:
arch/arm/include/debug/8250.S +2 -0
@@ -9,6 +9,18 @@
  */
 #include <linux/serial_reg.h>
 
+#ifdef CONFIG_DEBUG_UART_8250_PALMCHIP
+

arch/arm/include/debug/8250.S line 23

Quoted 10 lines
arch/arm/include/debug/8250.S +9 -0
+#undef UART_TX
+#undef UART_LSR
+#undef UART_MSR
+
+#define UART_TX 1
+#define UART_LSR 7
+#define UART_MSR 8
+
+#endif

Maybe use a separate file instead of an #ifdef?

Something like

arch/arm/include/debug/8250-palmchip.S:

#include <linux/serial_reg.h>

#undef UART_TX
#undef UART_LSR
#undef UART_MSR

#define UART_TX 1
#define UART_LSR 7
#define UART_MSR 8

#include "8250.S"

Arnd

author
#6 lore raw
Quoted 32 lines · Arnd Bergmann
Quoted 8 lines · On Tuesday 27 October 2015 12:57:57 Mans Rullgard wrote:
arch/arm/include/debug/8250.S +2 -0
@@ -9,6 +9,18 @@
  */
 #include <linux/serial_reg.h>
 
+#ifdef CONFIG_DEBUG_UART_8250_PALMCHIP
+

arch/arm/include/debug/8250.S line 23

Quoted 10 lines
arch/arm/include/debug/8250.S +9 -0
+#undef UART_TX
+#undef UART_LSR
+#undef UART_MSR
+
+#define UART_TX 1
+#define UART_LSR 7
+#define UART_MSR 8
+
+#endif

Maybe use a separate file instead of an #ifdef?

Something like

arch/arm/include/debug/8250-palmchip.S:

#include <linux/serial_reg.h>

#undef UART_TX
#undef UART_LSR
#undef UART_MSR

Quoted 5 lines

#define UART_TX 1
#define UART_LSR 7
#define UART_MSR 8

#include "8250.S"

Good idea. I'll make a new patch.

Signature · 2 lines
M?ns Rullg?rd
mans at mansr.com