[PATCH] ARM: EXYNOS: Consolidate multiple low-level UART port definitions

[PATCH] ARM: EXYNOS: Consolidate multiple low-level UART port definitions

[Tushar Behera]

There are two definitions for low-level UART ports for Exynos platform.
CONFIG_S3C_LOWLEVEL_UART_PORT is used for printing "Uncompressing
Linux... done, booting the kernel." and CONFIG_S3C_UART for other
low-level messages.

The assumption for both the uart ports is that they are pre-configured
in the bootloader. Since they are essentially the same always, it
would be good to consolidate them to use only one macro, in this case
'DEBUG_S3C_UART' would be a better option.

'DEBUG_S3C_UART' is defined only if DEBUG_LL is enabled. We can safely
disable this option when DEBUG_LL is not defined and we can boot various
boards with different UART port settings. Only drawback of this
approach is that when DEBUG_LL is not defined, we would be missing the
print "Uncompressing Linux... done, booting the kernel."

Since CONFIG_S3C_LOWLEVEL_UART_PORT is still used by other Samsung
boards, the consolidation applies only for ARCH_EXYNOS.

Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
---
 arch/arm/mach-exynos/include/mach/uncompress.h  |   11 ++++++++---
 arch/arm/plat-samsung/include/plat/uncompress.h |   16 ++++++++++++++--
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-exynos/include/mach/uncompress.h b/arch/arm/mach-exynos/include/mach/uncompress.h
index 2979995..45b5c2a 100644
--- a/arch/arm/mach-exynos/include/mach/uncompress.h
+++ b/arch/arm/mach-exynos/include/mach/uncompress.h
@@ -37,11 +37,16 @@ static void arch_detect_cpu(void)
 	chip_id >>= 20;
 	chip_id &= 0xf;
 
+#ifdef CONFIG_DEBUG_LL
 	if (chip_id == 0x5)
-		uart_base = (volatile u8 *)EXYNOS5_PA_UART + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT);
+		uart_base = (volatile u8 *)EXYNOS5_PA_UART +
+			(S3C_UART_OFFSET * CONFIG_DEBUG_S3C_UART);
 	else
-		uart_base = (volatile u8 *)EXYNOS4_PA_UART + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT);
-
+		uart_base = (volatile u8 *)EXYNOS4_PA_UART +
+			(S3C_UART_OFFSET * CONFIG_DEBUG_S3C_UART);
+#else
+	uart_base = 0;
+#endif
 	/*
 	 * For preventing FIFO overrun or infinite loop of UART console,
 	 * fifo_max should be the minimum fifo size of all of the UART channels
diff --git a/arch/arm/plat-samsung/include/plat/uncompress.h b/arch/arm/plat-samsung/include/plat/uncompress.h
index 438b248..028c2a8 100644
--- a/arch/arm/plat-samsung/include/plat/uncompress.h
+++ b/arch/arm/plat-samsung/include/plat/uncompress.h
@@ -38,7 +38,11 @@ static void arch_detect_cpu(void);
 #define FIFO_MAX	 (14)
 
 #ifdef S3C_PA_UART
-#define uart_base S3C_PA_UART + (S3C_UART_OFFSET * CONFIG_S3C_LOWLEVEL_UART_PORT)
+#ifdef CONFIG_DEBUG_LL
+#define uart_base (S3C_PA_UART + (S3C_UART_OFFSET * CONFIG_DEBUG_S3C_UART))
+#else
+#define uart_base 0
+#endif
 #endif
 
 static __inline__ void
@@ -66,6 +70,9 @@ uart_rd(unsigned int reg)
 
 static void putc(int ch)
 {
+	if (!uart_base)
+		return;
+
 	if (uart_rd(S3C2410_UFCON) & S3C2410_UFCON_FIFOMODE) {
 		int level;
 
@@ -118,7 +125,12 @@ static void arch_decomp_error(const char *x)
 #ifdef CONFIG_S3C_BOOT_UART_FORCE_FIFO
 static inline void arch_enable_uart_fifo(void)
 {
-	u32 fifocon = uart_rd(S3C2410_UFCON);
+	u32 fifocon;
+
+	if (!uart_base)
+		return;
+
+	fifocon = uart_rd(S3C2410_UFCON);
 
 	if (!(fifocon & S3C2410_UFCON_FIFOMODE)) {
 		fifocon |= S3C2410_UFCON_RESETBOTH;
-- 
1.7.9.5

[PATCH] ARM: EXYNOS: Consolidate multiple low-level UART port definitions

[Olof Johansson]

Hi,

On Wed, May 29, 2013 at 9:40 PM, Tushar Behera <tushar.behera@linaro.org> wrote:
> There are two definitions for low-level UART ports for Exynos platform.
> CONFIG_S3C_LOWLEVEL_UART_PORT is used for printing "Uncompressing
> Linux... done, booting the kernel." and CONFIG_S3C_UART for other
> low-level messages.
>
> The assumption for both the uart ports is that they are pre-configured
> in the bootloader. Since they are essentially the same always, it
> would be good to consolidate them to use only one macro, in this case
> 'DEBUG_S3C_UART' would be a better option.
>
> 'DEBUG_S3C_UART' is defined only if DEBUG_LL is enabled. We can safely
> disable this option when DEBUG_LL is not defined and we can boot various
> boards with different UART port settings. Only drawback of this
> approach is that when DEBUG_LL is not defined, we would be missing the
> print "Uncompressing Linux... done, booting the kernel."
>
> Since CONFIG_S3C_LOWLEVEL_UART_PORT is still used by other Samsung
> boards, the consolidation applies only for ARCH_EXYNOS.
>
> Signed-off-by: Tushar Behera <tushar.behera@linaro.org>

This looks reasonable, but you have to convert the other samsung
platforms too -- it's not ok to ignore them.


-Olof

[PATCH] ARM: EXYNOS: Consolidate multiple low-level UART port definitions

[Tushar Behera]

On 05/31/2013 02:41 AM, Olof Johansson wrote:
> Hi,
> 
> On Wed, May 29, 2013 at 9:40 PM, Tushar Behera <tushar.behera@linaro.org> wrote:
>> There are two definitions for low-level UART ports for Exynos platform.
>> CONFIG_S3C_LOWLEVEL_UART_PORT is used for printing "Uncompressing
>> Linux... done, booting the kernel." and CONFIG_S3C_UART for other
>> low-level messages.
>>
>> The assumption for both the uart ports is that they are pre-configured
>> in the bootloader. Since they are essentially the same always, it
>> would be good to consolidate them to use only one macro, in this case
>> 'DEBUG_S3C_UART' would be a better option.
>>
>> 'DEBUG_S3C_UART' is defined only if DEBUG_LL is enabled. We can safely
>> disable this option when DEBUG_LL is not defined and we can boot various
>> boards with different UART port settings. Only drawback of this
>> approach is that when DEBUG_LL is not defined, we would be missing the
>> print "Uncompressing Linux... done, booting the kernel."
>>
>> Since CONFIG_S3C_LOWLEVEL_UART_PORT is still used by other Samsung
>> boards, the consolidation applies only for ARCH_EXYNOS.
>>
>> Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
> 
> This looks reasonable, but you have to convert the other samsung
> platforms too -- it's not ok to ignore them.
> 

Sure thing. I will update those platforms in a subsequent patchset.

> 
> -Olof
> 


-- 
Tushar Behera

[PATCH] ARM: EXYNOS: Consolidate multiple low-level UART port definitions

[Kevin Hilman]

Tushar Behera <tushar.behera@linaro.org> writes:

> There are two definitions for low-level UART ports for Exynos platform.
> CONFIG_S3C_LOWLEVEL_UART_PORT is used for printing "Uncompressing
> Linux... done, booting the kernel." and CONFIG_S3C_UART for other
> low-level messages.
>
> The assumption for both the uart ports is that they are pre-configured
> in the bootloader. Since they are essentially the same always, it
> would be good to consolidate them to use only one macro, in this case
> 'DEBUG_S3C_UART' would be a better option.
>
> 'DEBUG_S3C_UART' is defined only if DEBUG_LL is enabled. We can safely
> disable this option when DEBUG_LL is not defined and we can boot various
> boards with different UART port settings. Only drawback of this
> approach is that when DEBUG_LL is not defined, we would be missing the
> print "Uncompressing Linux... done, booting the kernel."

Perfectly acceptable to me (and already the case on OMAP.)

> Since CONFIG_S3C_LOWLEVEL_UART_PORT is still used by other Samsung
> boards, the consolidation applies only for ARCH_EXYNOS.
>
> Signed-off-by: Tushar Behera <tushar.behera@linaro.org>

Acked-by: Kevin Hilman <khilman@linaro.org>

[PATCH] ARM: EXYNOS: Consolidate multiple low-level UART port definitions

[Tushar Behera]

On 05/31/2013 11:50 PM, Kevin Hilman wrote:
> Tushar Behera <tushar.behera@linaro.org> writes:
> 
>> There are two definitions for low-level UART ports for Exynos platform.
>> CONFIG_S3C_LOWLEVEL_UART_PORT is used for printing "Uncompressing
>> Linux... done, booting the kernel." and CONFIG_S3C_UART for other
>> low-level messages.
>>
>> The assumption for both the uart ports is that they are pre-configured
>> in the bootloader. Since they are essentially the same always, it
>> would be good to consolidate them to use only one macro, in this case
>> 'DEBUG_S3C_UART' would be a better option.
>>
>> 'DEBUG_S3C_UART' is defined only if DEBUG_LL is enabled. We can safely
>> disable this option when DEBUG_LL is not defined and we can boot various
>> boards with different UART port settings. Only drawback of this
>> approach is that when DEBUG_LL is not defined, we would be missing the
>> print "Uncompressing Linux... done, booting the kernel."
> 
> Perfectly acceptable to me (and already the case on OMAP.)
> 
>> Since CONFIG_S3C_LOWLEVEL_UART_PORT is still used by other Samsung
>> boards, the consolidation applies only for ARCH_EXYNOS.
>>
>> Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
> 
> Acked-by: Kevin Hilman <khilman@linaro.org>
> 

Thanks Kevin.

I have an updated version of this patch updated for all of Samsung
platforms.[1]

[1] http://www.gossamer-threads.com/lists/linux/kernel/1723429

-- 
Tushar Behera