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119 lines
4.1 KiB
Diff
119 lines
4.1 KiB
Diff
From 8a55d01fb0245d518898960123c3cb1b96dd9080 Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Tue, 15 Mar 2016 14:10:29 +0000
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Subject: [PATCH 185/304] bcm2835-sdhost: Workaround for "slow" sectors
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Some cards have been seen to cause timeouts after certain sectors are
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read. This workaround enforces a minimum delay between the stop after
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reading one of those sectors and a subsequent data command.
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Using CMD23 (SET_BLOCK_COUNT) avoids this problem, so good cards will
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not be penalised by this workaround.
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Signed-off-by: Phil Elwell <phil@raspberrypi.org>
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---
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drivers/mmc/host/bcm2835-sdhost.c | 50 +++++++++++++++++++++++++++++++++++----
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1 file changed, 46 insertions(+), 4 deletions(-)
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--- a/drivers/mmc/host/bcm2835-sdhost.c
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+++ b/drivers/mmc/host/bcm2835-sdhost.c
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@@ -202,9 +202,12 @@ struct bcm2835_host {
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int max_delay; /* maximum length of time spent waiting */
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struct timeval stop_time; /* when the last stop was issued */
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u32 delay_after_stop; /* minimum time between stop and subsequent data transfer */
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+ u32 delay_after_this_stop; /* minimum time between this stop and subsequent data transfer */
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u32 overclock_50; /* frequency to use when 50MHz is requested (in MHz) */
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u32 overclock; /* Current frequency if overclocked, else zero */
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u32 pio_limit; /* Maximum block count for PIO (0 = always DMA) */
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+
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+ u32 sectors; /* Cached card size in sectors */
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};
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#if ENABLE_LOG
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@@ -425,6 +428,7 @@ static void bcm2835_sdhost_reset_interna
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bcm2835_sdhost_set_power(host, true);
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mdelay(10);
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host->clock = 0;
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+ host->sectors = 0;
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bcm2835_sdhost_write(host, host->hcfg, SDHCFG);
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bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
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mmiowb();
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@@ -880,6 +884,24 @@ static void bcm2835_sdhost_prepare_data(
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host->flush_fifo = 0;
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host->data->bytes_xfered = 0;
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+ if (!host->sectors && host->mmc->card) {
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+ struct mmc_card *card = host->mmc->card;
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+ if (!mmc_card_sd(card) && mmc_card_blockaddr(card)) {
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+ /*
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+ * The EXT_CSD sector count is in number of 512 byte
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+ * sectors.
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+ */
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+ host->sectors = card->ext_csd.sectors;
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+ } else {
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+ /*
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+ * The CSD capacity field is in units of read_blkbits.
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+ * set_capacity takes units of 512 bytes.
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+ */
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+ host->sectors = card->csd.capacity <<
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+ (card->csd.read_blkbits - 9);
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+ }
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+ }
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+
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if (!host->dma_desc) {
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/* Use PIO */
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int flags = SG_MITER_ATOMIC;
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@@ -989,7 +1011,7 @@ bool bcm2835_sdhost_send_command(struct
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if (cmd->data) {
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log_event("CMDD", cmd->data->blocks, cmd->data->blksz);
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- if (host->delay_after_stop) {
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+ if (host->delay_after_this_stop) {
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struct timeval now;
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int time_since_stop;
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do_gettimeofday(&now);
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@@ -998,12 +1020,32 @@ bool bcm2835_sdhost_send_command(struct
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/* Possibly less than one second */
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time_since_stop = time_since_stop * 1000000 +
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(now.tv_usec - host->stop_time.tv_usec);
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- if (time_since_stop < host->delay_after_stop)
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- udelay(host->delay_after_stop -
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+ if (time_since_stop <
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+ host->delay_after_this_stop)
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+ udelay(host->delay_after_this_stop -
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time_since_stop);
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}
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}
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+ host->delay_after_this_stop = host->delay_after_stop;
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+ if ((cmd->data->flags & MMC_DATA_READ) && !host->use_sbc) {
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+ /* See if read crosses one of the hazardous sectors */
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+ u32 first_blk, last_blk;
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+
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+ /* Intentionally include the following sector because
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+ without CMD23/SBC the read may run on. */
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+ first_blk = host->mrq->cmd->arg;
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+ last_blk = first_blk + cmd->data->blocks;
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+
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+ if (((last_blk >= (host->sectors - 64)) &&
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+ (first_blk <= (host->sectors - 64))) ||
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+ ((last_blk >= (host->sectors - 32)) &&
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+ (first_blk <= (host->sectors - 32)))) {
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+ host->delay_after_this_stop =
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+ max(250u, host->delay_after_stop);
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+ }
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+ }
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+
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if (cmd->data->flags & MMC_DATA_WRITE)
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sdcmd |= SDCMD_WRITE_CMD;
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if (cmd->data->flags & MMC_DATA_READ)
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@@ -1078,7 +1120,7 @@ static void bcm2835_sdhost_transfer_comp
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if (!host->use_busy)
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bcm2835_sdhost_finish_command(host, NULL);
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- if (host->delay_after_stop)
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+ if (host->delay_after_this_stop)
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do_gettimeofday(&host->stop_time);
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}
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} else {
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