On Mon, Jul 21, 2025 at 03:35:00PM +0300, Jimmy Durand Wesolowski wrote: >From: Iulian Banaga <[email protected]> > >This is a fix for the sporadic mmc write failure: > mmc write failed > 0 blocks written: ERROR > >After this happens the emmc will remain in an error state >where subsequent read/writes fail with a timeout. > >The mmc driver sends CMD25 - WRITE_MULTIPLE_BLOCK which >can sporadically timeout. When this happens, the mmc driver >aborts the transfer and returns the above error messages. > >But the emmc still remains in data transfer mode, since >the timeout was decided by uboot, not by the emmc. > >Fix this by sending the STOP_TRANSMISSION command (CMD12) >and waiting for the emmc to be in ready state again (CMD13). > >Transferring data blocks after a CMD25 can take anywhere >between 5 and +15s on Samsung EMMCs and the current timeout >is not enough. Increase the timeout by 2x to accommodate the >long transfer times observed. > >Signed-off-by: Iulian Banaga <[email protected]> >Acked-by: Jimmy Durand Wesolowski <[email protected]> >--- > > drivers/mmc/mmc_write.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > >diff --git a/drivers/mmc/mmc_write.c b/drivers/mmc/mmc_write.c >index 90fcf2679bb..37a42887cab 100644 >--- a/drivers/mmc/mmc_write.c >+++ b/drivers/mmc/mmc_write.c >@@ -155,6 +155,7 @@ static ulong mmc_write_blocks(struct mmc *mmc, lbaint_t >start, > struct mmc_cmd cmd; > struct mmc_data data; > int timeout_ms = 1000; >+ int err; > > if ((start + blkcnt) > mmc_get_blk_desc(mmc)->lba) { > printf("MMC: block number 0x" LBAF " exceeds max(0x" LBAF ")\n", >@@ -181,9 +182,11 @@ static ulong mmc_write_blocks(struct mmc *mmc, lbaint_t >start, > data.blocksize = mmc->write_bl_len; > data.flags = MMC_DATA_WRITE; > >- if (mmc_send_cmd(mmc, &cmd, &data)) { >+ err = mmc_send_cmd(mmc, &cmd, &data); >+ if (err) { > printf("mmc write failed\n"); >- return 0; >+ // do not return 0 here since the emmc will still be in data >+ // transfer mode continue to send the STOP_TRANSMISSION command > } > > /* SPI multiblock writes terminate using a special >@@ -203,6 +206,9 @@ static ulong mmc_write_blocks(struct mmc *mmc, lbaint_t >start, > if (mmc_poll_for_busy(mmc, timeout_ms)) > return 0; > >+ if (err) >+ return 0; >+ > return blkcnt; > }
I would keep the comments aligned with others. I will update when apply the patch. Reviewed-by: Peng Fan <[email protected]> Thanks, Peng
