[U-Boot] [PATCH V9 2/4] omap-common: Add NAND SPL linux booting

[Stefano Babic]

On 06/12/2011 19:34, Simon Schwarz wrote:
> From: Simon Schwarz <simonschwarzcor at googlemail.com>
> 
> This implements booting of Linux from NAND in SPL
> 
> Related config parameters:
> CONFIG_SYS_NAND_SPL_KERNEL_OFFS
> 	Offset in NAND of direct boot kernel image to use in SPL
> CONFIG_SYS_SPL_ARGS_ADDR
> 	Address where the kernel boot arguments are expected - this is
> 	normally RAM-start + 0x100 (on ARM)
> 
> Signed-off-by: Simon Schwarz <simonschwarzcor at gmail.com>
> 
> ---

Hi Simon,


> 
> diff --git a/arch/arm/cpu/armv7/omap-common/spl_nand.c b/arch/arm/cpu/armv7/omap-common/spl_nand.c
> index 38d06b1..db52879 100644
> --- a/arch/arm/cpu/armv7/omap-common/spl_nand.c
> +++ b/arch/arm/cpu/armv7/omap-common/spl_nand.c
> @@ -24,6 +24,7 @@
>  #include <asm/u-boot.h>
>  #include <asm/utils.h>
>  #include <asm/arch/sys_proto.h>
> +#include <asm/io.h>
>  #include <nand.h>
>  #include <version.h>
>  #include <asm/omap_common.h>
> @@ -32,6 +33,7 @@
>  void spl_nand_load_image(void)
>  {
>  	struct image_header *header;
> +	int *src, *dst;
>  	switch (omap_boot_mode()) {
>  	case NAND_MODE_HW_ECC:
>  		debug("spl: nand - using hw ecc\n");
> @@ -45,26 +47,56 @@ void spl_nand_load_image(void)
>  
>  	/*use CONFIG_SYS_TEXT_BASE as temporary storage area */
>  	header = (struct image_header *)(CONFIG_SYS_TEXT_BASE);
> +#ifdef CONFIG_SPL_OS_BOOT
> +	if (!spl_uboot_key()) {

Using a gpio or whatever mechanis is baord specific. What about to set a
weak function and let that the board decides itself what to do ?

Not always a GPIO can be used for this purpose.

I have noted another issue. If the kernel image is not found, the
fallback is to load u-boot. However, u-boot is searched at the address
in NAND of the kernel, not at CONFIG_SYS_NAND_U_BOOT_OFFS.

This means that if the kernel is not loaded at all, the SPL starts to
start a u-boot.bin instead of u-boot.img loaded at
CONFIG_CMD_SPL_NAND_OFS, and this fails.

> +		/*
> +		 * load parameter image
> +		 * load to temp position since nand_spl_load_image reads
> +		 * a whole block which is typically larger than
> +		 * CONFIG_CMD_SAVEBP_WRITE_SIZE therefore may overwrite
> +		 * following sections like BSS
> +		 */
> +		nand_spl_load_image(CONFIG_CMD_SPL_NAND_OFS,
> +			CONFIG_CMD_SPL_WRITE_SIZE,
> +			(void *)CONFIG_SYS_TEXT_BASE);
> +		/* copy to destintion */
> +		for (dst = (int *)CONFIG_SYS_SPL_ARGS_ADDR,
> +				src = (int *)CONFIG_SYS_TEXT_BASE;
> +				src < (int *)(CONFIG_SYS_TEXT_BASE +
> +				CONFIG_CMD_SPL_WRITE_SIZE);
> +				src++, dst++) {
> +			writel(readl(src), dst);
> +		}
>  
> +		/* load linux */
> +		nand_spl_load_image(CONFIG_SYS_NAND_SPL_KERNEL_OFFS,
> +			CONFIG_SYS_NAND_PAGE_SIZE, (void *)header);
> +		spl_parse_image_header(header);

So if the parse function fails, we should have the fallback to u-boot,
exactly as we have now the fallback from u-boot.img to u-boot.bin.


The function you write are in omap-common/spl_nand.c, but they are not
specific for OMAP, and any architecture can profit from your work. What
about to move common functions away from TI related directory ? I do not
know which is the best place, maybe a new directory under the root as
spllib ?

Stefano

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