[PATCH] mmc: fsl_esdhc_spl: pre-PBL: implement redundancy support

[Jaehoon Chung]

On 4/5/22 01:33, Pali Rohár wrote:
> QorIQ pre-PBL BootROM scans first 24 SD card sectors (each with fixed 512
> bytes length) for boot signature. Implement same redundancy behavior in
> fsl_esdhc_spl driver to allow loading proper U-Boot when boot sector is not
> the first one.
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>
> ---
>  drivers/mmc/fsl_esdhc_spl.c | 25 ++++++++++++++++++-------
>  1 file changed, 18 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/mmc/fsl_esdhc_spl.c b/drivers/mmc/fsl_esdhc_spl.c
> index 0146a231b221..ea8f4cd66964 100644
> --- a/drivers/mmc/fsl_esdhc_spl.c
> +++ b/drivers/mmc/fsl_esdhc_spl.c
> @@ -20,7 +20,6 @@
>  #define ESDHC_BOOT_IMAGE_ADDR	0x50
>  #define MBRDBR_BOOT_SIG_55	0x1fe
>  #define MBRDBR_BOOT_SIG_AA	0x1ff
> -#define CONFIG_CFG_DATA_SECTOR	0
>  
>  
>  void mmc_spl_load_image(uint32_t offs, unsigned int size, void *vdst)
> @@ -62,11 +61,13 @@ void __noreturn mmc_boot(void)
>  #ifndef CONFIG_FSL_CORENET
>  	uchar *tmp_buf;
>  	u32 blklen;
> +	u32 blk_off;
>  	uchar val;
>  #ifndef CONFIG_SPL_FSL_PBL
>  	u32 val32;
>  #endif
>  	uint i, byte_num;
> +	u32 sector;
>  #endif
>  	u32 offset, code_len;
>  	struct mmc *mmc;
> @@ -86,30 +87,37 @@ void __noreturn mmc_boot(void)
>  	offset = CONFIG_SYS_MMC_U_BOOT_OFFS;
>  #else
>  	blklen = mmc->read_bl_len;
> +	if (blklen < 512)
> +		blklen = 512;
>  	tmp_buf = malloc(blklen);
>  	if (!tmp_buf) {
>  		puts("spl: malloc memory failed!!\n");
>  		hang();
>  	}
> +
> +	sector = 0;

Why does it assign to 0 at here? Doesn't initialize this at above?
Does it need to check whether CONFIG_SPL_FSL_PBL enabled or not?

Best Regards,
Jaehoon Chung

> +again:
>  	memset(tmp_buf, 0, blklen);
>  
>  	/*
>  	* Read source addr from sd card
>  	*/
> -	err = mmc->block_dev.block_read(&mmc->block_dev,
> -					CONFIG_CFG_DATA_SECTOR, 1, tmp_buf);
> +	blk_start = (sector * 512) / mmc->read_bl_len;
> +	blk_off = (sector * 512) % mmc->read_bl_len;
> +	blk_cnt = DIV_ROUND_UP(512,  mmc->read_bl_len);
> +	err = mmc->block_dev.block_read(&mmc->block_dev, blk_start, blk_cnt, tmp_buf);
>  	if (err != 1) {
>  		puts("spl: mmc read failed!!\n");
>  		hang();
>  	}
>  
>  #ifdef CONFIG_SPL_FSL_PBL
> -	val = *(tmp_buf + MBRDBR_BOOT_SIG_55);
> +	val = *(tmp_buf + blk_off + MBRDBR_BOOT_SIG_55);
>  	if (0x55 != val) {
>  		puts("spl: mmc MBR/DBR signature is not valid!!\n");
>  		hang();
>  	}
> -	val = *(tmp_buf + MBRDBR_BOOT_SIG_AA);
> +	val = *(tmp_buf + blk_off + MBRDBR_BOOT_SIG_AA);
>  	if (0xAA != val) {
>  		puts("spl: mmc MBR/DBR signature is not valid!!\n");
>  		hang();
> @@ -123,10 +131,13 @@ void __noreturn mmc_boot(void)
>  	byte_num = 4;
>  	val32 = 0;
>  	for (i = 0; i < byte_num; i++) {
> -		val = *(tmp_buf + ESDHC_BOOT_SIGNATURE_OFF + i);
> +		val = *(tmp_buf + blk_off + ESDHC_BOOT_SIGNATURE_OFF + i);
>  		val32 = (val32 << 8) + val;
>  	}
>  	if (val32 != ESDHC_BOOT_SIGNATURE) {
> +		/* BOOT signature may be on the first 24 sectors (each being 512 bytes) */
> +		if (++sector < 24)
> +			goto again;
>  		puts("spl: mmc BOOT signature is not valid!!\n");
>  		hang();
>  	}
> @@ -135,7 +146,7 @@ void __noreturn mmc_boot(void)
>  	byte_num = 4;
>  	offset = 0;
>  	for (i = 0; i < byte_num; i++) {
> -		val = *(tmp_buf + ESDHC_BOOT_IMAGE_ADDR + i);
> +		val = *(tmp_buf + blk_off + ESDHC_BOOT_IMAGE_ADDR + i);
>  		offset = (offset << 8) + val;
>  	}
>  	offset += CONFIG_SYS_MMC_U_BOOT_OFFS;