diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0186-bcm2835-sdhost-Workaround-for-slow-sectors.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0186-bcm2835-sdhost-Workaround-for-slow-sectors.patch | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0186-bcm2835-sdhost-Workaround-for-slow-sectors.patch b/target/linux/brcm2708/patches-4.4/0186-bcm2835-sdhost-Workaround-for-slow-sectors.patch new file mode 100644 index 0000000000..26f64a1811 --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0186-bcm2835-sdhost-Workaround-for-slow-sectors.patch @@ -0,0 +1,118 @@ +From c215c0d855343400b53ae2ec8b015a3f4a3eb27e Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Tue, 15 Mar 2016 14:10:29 +0000 +Subject: [PATCH 186/232] bcm2835-sdhost: Workaround for "slow" sectors + +Some cards have been seen to cause timeouts after certain sectors are +read. This workaround enforces a minimum delay between the stop after +reading one of those sectors and a subsequent data command. + +Using CMD23 (SET_BLOCK_COUNT) avoids this problem, so good cards will +not be penalised by this workaround. + +Signed-off-by: Phil Elwell <phil@raspberrypi.org> +--- + drivers/mmc/host/bcm2835-sdhost.c | 50 +++++++++++++++++++++++++++++++++++---- + 1 file changed, 46 insertions(+), 4 deletions(-) + +--- a/drivers/mmc/host/bcm2835-sdhost.c ++++ b/drivers/mmc/host/bcm2835-sdhost.c +@@ -202,9 +202,12 @@ struct bcm2835_host { + int max_delay; /* maximum length of time spent waiting */ + struct timeval stop_time; /* when the last stop was issued */ + u32 delay_after_stop; /* minimum time between stop and subsequent data transfer */ ++ u32 delay_after_this_stop; /* minimum time between this stop and subsequent data transfer */ + u32 overclock_50; /* frequency to use when 50MHz is requested (in MHz) */ + u32 overclock; /* Current frequency if overclocked, else zero */ + u32 pio_limit; /* Maximum block count for PIO (0 = always DMA) */ ++ ++ u32 sectors; /* Cached card size in sectors */ + }; + + #if ENABLE_LOG +@@ -425,6 +428,7 @@ static void bcm2835_sdhost_reset_interna + bcm2835_sdhost_set_power(host, true); + mdelay(10); + host->clock = 0; ++ host->sectors = 0; + bcm2835_sdhost_write(host, host->hcfg, SDHCFG); + bcm2835_sdhost_write(host, host->cdiv, SDCDIV); + mmiowb(); +@@ -880,6 +884,24 @@ static void bcm2835_sdhost_prepare_data( + host->flush_fifo = 0; + host->data->bytes_xfered = 0; + ++ if (!host->sectors && host->mmc->card) { ++ struct mmc_card *card = host->mmc->card; ++ if (!mmc_card_sd(card) && mmc_card_blockaddr(card)) { ++ /* ++ * The EXT_CSD sector count is in number of 512 byte ++ * sectors. ++ */ ++ host->sectors = card->ext_csd.sectors; ++ } else { ++ /* ++ * The CSD capacity field is in units of read_blkbits. ++ * set_capacity takes units of 512 bytes. ++ */ ++ host->sectors = card->csd.capacity << ++ (card->csd.read_blkbits - 9); ++ } ++ } ++ + if (!host->dma_desc) { + /* Use PIO */ + int flags = SG_MITER_ATOMIC; +@@ -989,7 +1011,7 @@ bool bcm2835_sdhost_send_command(struct + + if (cmd->data) { + log_event("CMDD", cmd->data->blocks, cmd->data->blksz); +- if (host->delay_after_stop) { ++ if (host->delay_after_this_stop) { + struct timeval now; + int time_since_stop; + do_gettimeofday(&now); +@@ -998,12 +1020,32 @@ bool bcm2835_sdhost_send_command(struct + /* Possibly less than one second */ + time_since_stop = time_since_stop * 1000000 + + (now.tv_usec - host->stop_time.tv_usec); +- if (time_since_stop < host->delay_after_stop) +- udelay(host->delay_after_stop - ++ if (time_since_stop < ++ host->delay_after_this_stop) ++ udelay(host->delay_after_this_stop - + time_since_stop); + } + } + ++ host->delay_after_this_stop = host->delay_after_stop; ++ if ((cmd->data->flags & MMC_DATA_READ) && !host->use_sbc) { ++ /* See if read crosses one of the hazardous sectors */ ++ u32 first_blk, last_blk; ++ ++ /* Intentionally include the following sector because ++ without CMD23/SBC the read may run on. */ ++ first_blk = host->mrq->cmd->arg; ++ last_blk = first_blk + cmd->data->blocks; ++ ++ if (((last_blk >= (host->sectors - 64)) && ++ (first_blk <= (host->sectors - 64))) || ++ ((last_blk >= (host->sectors - 32)) && ++ (first_blk <= (host->sectors - 32)))) { ++ host->delay_after_this_stop = ++ max(250u, host->delay_after_stop); ++ } ++ } ++ + if (cmd->data->flags & MMC_DATA_WRITE) + sdcmd |= SDCMD_WRITE_CMD; + if (cmd->data->flags & MMC_DATA_READ) +@@ -1078,7 +1120,7 @@ static void bcm2835_sdhost_transfer_comp + if (!host->use_busy) + bcm2835_sdhost_finish_command(host, NULL); + +- if (host->delay_after_stop) ++ if (host->delay_after_this_stop) + do_gettimeofday(&host->stop_time); + } + } else { |