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

[Pali Rohár]

On Friday 22 April 2022 21:32:54 Jaehoon Chung wrote:
> 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?

All variables in this file are initialized after declaration. So I used
this same coding style also for newly introduced variables.

> Does it need to check whether CONFIG_SPL_FSL_PBL enabled or not?

This redundancy (retry) is implemented only for pre-PBL BootROMs (when
CONFIG_SPL_FSL_PBL is not enabled). I do not know how it works in PBL
BootROMs, so PBL code scans only sector 0, like before.

> 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;