[U-Boot] [PATCH v2 3/7] da850/omap-l138: Add support to read u-boot image from MMC/SD

[Christian Riesch]

Hi Prabhakar,

On Tue, Jun 19, 2012 at 7:06 AM, Lad, Prabhakar <prabhakar.lad at ti.com> wrote:
> Hi Christian,
>
> On Tue, Jun 19, 2012 at 01:09:08, Christian Riesch wrote:
>> Hi,
>> Sorry for the delay, had a lot of other work to do :-/
>>
>> On Thursday, June 7, 2012, Prabhakar Lad wrote:
>>
>>
>>       From: Lad, Prabhakar <prabhakar.lad at ti.com <javascript:;> >
>>
>>       DA850/OMAP-L138 does not support strict MMC/SD boot mode. SPL will
>>       be in SPI flash and U-Boot image will be in MMC/SD card. SPL will
>>       do the low level initialization and then loads the u-boot image
>>       from MMC/SD card.
>>
>>       Define the CONFIG_SPL_MMC_LOAD macro in the DA850/OMAP-L138
>>       configuration file to enable this feature.
>>
>>       Signed-off-by: Lad, Prabhakar <prabhakar.lad at ti.com <javascript:;> >
>>       Signed-off-by: Rajashekhara, Sudhakar <sudhakar.raj at ti.com <javascript:;> >
>>       Signed-off-by: Hadli, Manjunath <manjunath.hadli at ti.com <javascript:;> >
>>       ---
>>        arch/arm/cpu/arm926ejs/davinci/spl.c |   12 ++++++-
>>        drivers/mmc/Makefile                 |    4 ++
>>        drivers/mmc/spl_mmc_load.c           |   62
>> ++++++++++++++++++++++++++++++++++
>>        include/configs/da850evm.h           |    8 ++++
>>        include/mmc.h                        |    2 +
>>        5 files changed, 87 insertions(+), 1 deletions(-)
>>        create mode 100644 drivers/mmc/spl_mmc_load.c
>>
>>       diff --git a/arch/arm/cpu/arm926ejs/davinci/spl.c
>> b/arch/arm/cpu/arm926ejs/davinci/spl.c
>>       index 74632e5..be397ce 100644
>>       --- a/arch/arm/cpu/arm926ejs/davinci/spl.c
>>       +++ b/arch/arm/cpu/arm926ejs/davinci/spl.c
>>       @@ -28,6 +28,11 @@
>>        #include <ns16550.h>
>>        #include <malloc.h>
>>        #include <spi_flash.h>
>>       +#include <mmc.h>
>>       +#include <fat.h>
>>       +#include <version.h>
>>       +#include <asm/arch/davinci_misc.h>
>>       +#include <asm/arch/pinmux_defs.h>
>>
>>        #ifdef CONFIG_SPL_LIBCOMMON_SUPPORT
>>
>>       @@ -91,6 +96,11 @@ void board_init_r(gd_t *id, ulong dummy)
>>              gd->have_console = 1;
>>
>>              puts("SPI boot...\n");
>>       +#ifdef CONFIG_SPL_MMC_LOAD
>>       +       spl_mmc_load();
>>       +#else
>>              spi_boot();
>>       -#endif
>>
>>
>> Hmm, now the code prints "SPI boot" and then it boots from MMC, right?
>> Please output correct messages.
>>
>  The board is booted up in SPI boot mode only, ie the SPL is loaded from
>  SPI flash itself and finally when low level initialization is completed
>  The SPL loads the U-boot image in MMC/SD card when CONFIG_SPL_MMC_LOAD
>  Config is defined. If CONFIG_SPL_MMC_LOAD is not defined by default the
>  SPL loads the U-boot image from SPI flash itself.

Yes, but your code prints "SPI boot" for both cases, doesn't it?

>>
>>       +#endif /* CONFIG_SPL_MMC_LOAD */
>>       +
>>       +#endif /* CONFIG_SPL_SPI_LOAD */
>>
>>
>> So, CONFIG_SPL_SPI_LOAD must be defined to boot from MMC?? Ths does not make sense to me.
>
>  No not to boot from MMC, its indicating to SPL which is flashed in
>  SPI flash to load the U-boot image(u-boot.bin) from MMC.

Yes, but your code requires both CONFIG_SPL_MMC_LOAD and
CONFIG_SPL_SPI_LOAD to be defined to load u-boot from MMC, right? This
is confusing.

Of course SPL itself is loaded from SPI flash in both cases, but this
does not matter here, since the SPL has already loaded to the internal
SRAM of the SoC by the ROM bootloader of the chip. The SPL could have
been loaded from some other kind of memory (or UART) as well and would
not know the difference.

Regards, Christian

>
> Thx,
> --Prabhakar Lad
>
>>
>> Regards, Christian
>>
>
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