Kevin
>-----Original Message-----
>From: Kevin Hilman [mailto:khil...@deeprootsystems.com]
>Sent: Saturday, August 22, 2009 2:57 AM
>To: Pandita, Vikram
>Cc: linux-omap@vger.kernel.org; linux-arm-ker...@lists.arm.linux.org.uk
>Subject: Re: [PATCH 1/5] OMAP1/2/3/4: DEBUG_LL: cleanup
>
>Vikram Pandita wrote:
>> This patch cleans up the DEBUG_LL infrastructure for omap boards.
>
>Thanks Vikram, this is indeed in need of some cleanup. But I have some
>comments about the approach taken.
>
>This approach still doesn't solve one of the fundamental problems with
>the current implementation. It prevents using a single kernel across
>multiple boards. If we could drop the compile-time decision in favor of
>a runtime one based on machine-type, we could use a single base
>defconfig that would be able to be tested on all omap3 boards for example.
>
>For the zImage UART output (uncompress.h) there is a global variable
>__machine_arch_type which could be used to check the board type and set
>variable for UART base and shift. We do this on DaVinci.
Could you give reference to this code on DaVinci?
Yes this is doable, but the question is, how do we pass these variables to the
kernel start:
arch/arm/kernel/head.S
First stage, arch/arm/boot/compressed/head.S gets the arch type ->
shift/uart-addr. Fine.
This stage ends with relocated code over righting the decompressor.
Second stage, arch/arm/kernel/head.S now starts.
I am not sure how to share the data from Stage 1 in this stage?
>
>For debug output (debug-macro.S) those macros should be changed to use
>variables for UART base and shift also. While you're in changing the
>board files, you could also add something like this to each:
>
>#ifdef CONFIG_SERIAL_8250_CONSOLE
>static int __init board_console_init(void)
>{
> return add_preferred_console("ttyS", <UART#>, "115200");
>}
>console_initcall(board_console_init);
>#endif
>
>This also allows the board to boot using a default UART even without
>having the console= on the cmdline.
>
>There is one catch to doing this at runtime instead of compile time.
>The variables for the UART base and shift have to be set very early in
>the boot, otherwise any errors from the early ARM asm boot (head.S) will
>be missed.
>
>For starters, they could be assingned in the board map_io hook, but we'd
>still miss the debug prints if there were any errors parsing the
>machine_type and processor_type early in the boot (head.S)
>
>I'd be ok with this limitation for a first pass because it's still
>better than what we currently have in l-o, but I'd like to hear if
>others had some ideas for how we might do dynamic decisions on UART
>based on board-type very early in the boot.
>
>Kevin
>
>> The three stages of log printing infrastructure is using their own #defines
>> The patch integrates the three stages to use the same variable.
>>
>> Three stages are:
>> Stage 1: Prints - Uncompressing Linux......
>> File getting used: arch/arm/plat-omap/include/mach/uncompress.h
>> Stage 2: Prints - <5>Linux version 2.6.31
>> File getting used: arch/arm/plat-omap/include/mach/debug-macro.S
>> Stage 3: Kernel ttyS console takes over
>>
>> On enabling the DEBUG_LL menuconfig item
>> [Kernel Hacking -> Kernel low-level debugging functions]
>>
>> the following entry gets auto selected
>> [Systerm Type -> TI OMAP Implementations -> Low-level Debug console UART]
>>
>> This is the physical address of the UART getting used for the board.
>> The physical address of debug uart is provided as a menuconfig option now.
>>
>> Issue with current system:
>> (a) Zoom2 board has a detachable debug board having the TL16CP754 Quad uart
>> chip.
>> If the debug board is not attached, _NO_ debug uart is available.
>> OMAP internal uarts are not used for traces on zoom2 board.
>> Current framework does not account for boards that may not have a debug uart
>> at all. The Stage 1 always accesses one of the uarts. Thats fixed now.
>>
>> (b) this patch does a cleanup of
>> arch/arm/plat-omap/include/mach/debug-macro.S
>>
>> Signed-off-by: Vikram Pandita <vikram.pand...@ti.com>
>> ---
>> arch/arm/plat-omap/Kconfig | 50
>> ++++++++++++++++++-------
>> arch/arm/plat-omap/include/mach/common.h | 7 +++
>> arch/arm/plat-omap/include/mach/debug-macro.S | 40 ++++----------------
>> arch/arm/plat-omap/include/mach/uncompress.h | 12 +----
>> 4 files changed, 54 insertions(+), 55 deletions(-)
>>
>> diff --git a/arch/arm/plat-omap/Kconfig b/arch/arm/plat-omap/Kconfig
>> index ab9f9ef..2fefb64 100644
>> --- a/arch/arm/plat-omap/Kconfig
>> +++ b/arch/arm/plat-omap/Kconfig
>> @@ -162,21 +162,43 @@ config OMAP_DM_TIMER
>> help
>> Select this option if you want to use OMAP Dual-Mode timers.
>>
>> -choice
>> - prompt "Low-level debug console UART"
>> - depends on ARCH_OMAP
>> - default OMAP_LL_DEBUG_UART1
>> -
>> -config OMAP_LL_DEBUG_UART1
>> - bool "UART1"
>> -
>> -config OMAP_LL_DEBUG_UART2
>> - bool "UART2"
>>
>> -config OMAP_LL_DEBUG_UART3
>> - bool "UART3"
>> -
>> -endchoice
>> +config OMAP_DEBUG_LL_UART_PHY_ADDR
>> + hex "Low-level debug console UART Physical Address"
>> + depends on ARCH_OMAP && DEBUG_LL
>> +
>> + default "0xfffb0800" if ARCH_OMAP1 && (MACH_OMAP_PALMTT || MACH_SX1)
>> + default "0xfffb0000" if ARCH_OMAP1
>> + default "0x4806e000" if ARCH_OMAP2 && MACH_NOKIA_N8X0
>> + default "0x4806a000" if ARCH_OMAP2
>> + default "0x49020000" if ARCH_OMAP3 && (MACH_NOKIA_RX51 ||
>> MACH_OMAP_BEAGLE)
>> + default "0x49020000" if ARCH_OMAP3 && (MACH_OMAP3_PANDORA ||
>> MACH_OMAP_LDP || MACH_OVERO)
>> + default "0x10000000" if ARCH_OMAP3 && MACH_OMAP_ZOOM2
>> + default "0x4806a000" if ARCH_OMAP3
>> + default "0x4806a000" if ARCH_OMAP4
>> + help
>> + Specify the Physical address of Low level debug UART
>> + Specify 0x0 in case you do not want DEBUG_LL functions to iterfere
>> with your board uarts
>> +
>> + OMAP1:
>> + -------------------
>> + UART1 -> 0xfffb0000 (default)
>> + UART2 -> 0xfffb0800
>> + UART3 -> 0xfffb9800 (sx1, palmtt)
>> +
>> + OMAP2:
>> + -------------------
>> + UART1 -> 0x4806a000 (default)
>> + UART2 -> 0x4806c000
>> + UART3 -> 0x4806e000 (N8X0)
>> +
>> + OMAP3/4:
>> + -------------------
>> + UART1 -> 0x4806a000 (default: except following)
>> + UART2 -> 0x4806c000
>> + UART3 -> 0x49020000 (rx51, beagle, pendora, ldp, overo)
>> + UART4 -> 0x4806e000
>> + UART_EXT -> 0x10000000 (zoom2: Debug uart is on external debug
>> board)
>>
>> config OMAP_SERIAL_WAKE
>> bool "Enable wake-up events for serial ports"
>> diff --git a/arch/arm/plat-omap/include/mach/common.h
>> b/arch/arm/plat-omap/include/mach/common.h
>> index fdeab42..f29d31f 100644
>> --- a/arch/arm/plat-omap/include/mach/common.h
>> +++ b/arch/arm/plat-omap/include/mach/common.h
>> @@ -68,4 +68,11 @@ void omap2_set_globals_sdrc(struct omap_globals *);
>> void omap2_set_globals_control(struct omap_globals *);
>> void omap2_set_globals_prcm(struct omap_globals *);
>>
>> +/* In case Low Level debug is not defined
>> + * make the low level uart address as zero
>> + */
>> +#if !defined(CONFIG_DEBUG_LL)
>> +#define CONFIG_OMAP_DEBUG_LL_UART_PHY_ADDR 0
>> +#endif
>> +
>> #endif /* __ARCH_ARM_MACH_OMAP_COMMON_H */
>> diff --git a/arch/arm/plat-omap/include/mach/debug-macro.S
>> b/arch/arm/plat-omap/include/mach/debug-
>macro.S
>> index ac24050..f546d6c 100644
>> --- a/arch/arm/plat-omap/include/mach/debug-macro.S
>> +++ b/arch/arm/plat-omap/include/mach/debug-macro.S
>> @@ -10,43 +10,19 @@
>> * published by the Free Software Foundation.
>> *
>> */
>> +#include "io.h"
>>
>> .macro addruart,rx
>> mrc p15, 0, \rx, c1, c0
>> tst \rx, #1 @ MMU enabled?
>> #ifdef CONFIG_ARCH_OMAP1
>> - moveq \rx, #0xff000000 @ physical base address
>> - movne \rx, #0xfe000000 @ virtual base
>> - orr \rx, \rx, #0x00fb0000
>> -#ifdef CONFIG_OMAP_LL_DEBUG_UART3
>> - orr \rx, \rx, #0x00009000 @ UART 3
>> -#endif
>> -#if defined(CONFIG_OMAP_LL_DEBUG_UART2) ||
>> defined(CONFIG_OMAP_LL_DEBUG_UART3)
>> - orr \rx, \rx, #0x00000800 @ UART 2 & 3
>> -#endif
>> -
>> -#elif CONFIG_ARCH_OMAP2
>> - moveq \rx, #0x48000000 @ physical base address
>> - movne \rx, #0xd8000000 @ virtual base
>> - orr \rx, \rx, #0x0006a000
>> -#ifdef CONFIG_OMAP_LL_DEBUG_UART2
>> - add \rx, \rx, #0x00002000 @ UART 2
>> -#endif
>> -#ifdef CONFIG_OMAP_LL_DEBUG_UART3
>> - add \rx, \rx, #0x00004000 @ UART 3
>> -#endif
>> -
>> -#elif defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_ARCH_OMAP4)
>> - moveq \rx, #0x48000000 @ physical base address
>> - movne \rx, #0xd8000000 @ virtual base
>> - orr \rx, \rx, #0x0006a000
>> -#ifdef CONFIG_OMAP_LL_DEBUG_UART2
>> - add \rx, \rx, #0x00002000 @ UART 2
>> -#endif
>> -#ifdef CONFIG_OMAP_LL_DEBUG_UART3
>> - add \rx, \rx, #0x00fb0000 @ UART 3
>> - add \rx, \rx, #0x00006000
>> -#endif
>> + /* omap1 */
>> + ldr \rx, =CONFIG_OMAP_DEBUG_LL_UART_PHY_ADDR @ physical
>> base address
>> + subne \rx, #CONFIG_OMAP_DEBUG_LL_UART_PHY_ADDR,
>> #OMAP1_IO_OFFSET @ virtual base
>> +#else
>> + /* omap2/omap3/omap4 */
>> + ldr \rx, =CONFIG_OMAP_DEBUG_LL_UART_PHY_ADDR @ physical
>> base address
>> + orrne \rx, \rx, #OMAP2_IO_OFFSET @ virtual base
>> #endif
>> .endm
>>
>> diff --git a/arch/arm/plat-omap/include/mach/uncompress.h b/arch/arm/plat-
>omap/include/mach/uncompress.h
>> index 0814c5f..0e21eb3 100644
>> --- a/arch/arm/plat-omap/include/mach/uncompress.h
>> +++ b/arch/arm/plat-omap/include/mach/uncompress.h
>> @@ -38,14 +38,8 @@ static void putc(int c)
>> return;
>> #endif
>>
>> -#ifdef CONFIG_ARCH_OMAP
>> -#ifdef CONFIG_OMAP_LL_DEBUG_UART3
>> - uart = (volatile u8 *)(OMAP_UART3_BASE);
>> -#elif defined(CONFIG_OMAP_LL_DEBUG_UART2)
>> - uart = (volatile u8 *)(OMAP_UART2_BASE);
>> -#else
>> - uart = (volatile u8 *)(OMAP_UART1_BASE);
>> -#endif
>> +#if defined(CONFIG_DEBUG_LL)
>> + uart = (volatile u8 *)(CONFIG_OMAP_DEBUG_LL_UART_PHY_ADDR);
>>
>> #ifdef CONFIG_ARCH_OMAP1
>> /* Determine which serial port to use */
>> @@ -62,7 +56,6 @@ static void putc(int c)
>> return;
>> } while (0);
>> #endif /* CONFIG_ARCH_OMAP1 */
>> -#endif
>>
>> /*
>> * Now, xmit each character
>> @@ -70,6 +63,7 @@ static void putc(int c)
>> while (!(uart[UART_LSR << shift] & UART_LSR_THRE))
>> barrier();
>> uart[UART_TX << shift] = c;
>> +#endif /* CONFIG_DEBUG_LL */
>> }
>>
>> static inline void flush(void)
>
>
>
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