--- /dev/null
+From f99bed36f644ebf32e90f49559aac7a663a9fa59 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.org>
+Date: Tue, 19 Jan 2016 17:16:38 +0000
+Subject: [PATCH 136/156] bcm2835-sdhost: Add workaround for odd behaviour on
+ some cards
+
+For reasons not understood, the sdhost driver fails when reading
+sectors very near the end of some SD cards. The problem could
+be related to the similar issue that reading the final sector
+of any card as part of a multiple read never completes, and the
+workaround is an extension of the mechanism introduced to solve
+that problem which ensures those sectors are always read singly.
+---
+ drivers/mmc/host/bcm2835-sdhost.c | 61 +++++++++++++++++++++++++++++++++------
+ 1 file changed, 52 insertions(+), 9 deletions(-)
+
+--- a/drivers/mmc/host/bcm2835-sdhost.c
++++ b/drivers/mmc/host/bcm2835-sdhost.c
+@@ -173,6 +173,9 @@ struct bcm2835_host {
+ 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 */
++ u32 single_read_sectors[8];
+ };
+
+
+@@ -277,6 +280,9 @@ static void bcm2835_sdhost_reset_interna
+ {
+ u32 temp;
+
++ if (host->debug)
++ pr_info("%s: reset\n", mmc_hostname(host->mmc));
++
+ bcm2835_sdhost_set_power(host, false);
+
+ bcm2835_sdhost_write(host, 0, SDCMD);
+@@ -299,6 +305,8 @@ static void bcm2835_sdhost_reset_interna
+ bcm2835_sdhost_set_power(host, true);
+ mdelay(10);
+ host->clock = 0;
++ host->sectors = 0;
++ host->single_read_sectors[0] = ~0;
+ bcm2835_sdhost_write(host, host->hcfg, SDHCFG);
+ bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
+ mmiowb();
+@@ -309,8 +317,6 @@ static void bcm2835_sdhost_reset(struct
+ {
+ struct bcm2835_host *host = mmc_priv(mmc);
+ unsigned long flags;
+- if (host->debug)
+- pr_info("%s: reset\n", mmc_hostname(mmc));
+ spin_lock_irqsave(&host->lock, flags);
+
+ bcm2835_sdhost_reset_internal(host);
+@@ -676,6 +682,32 @@ 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;
++ pr_err("%s: using ext_csd!\n", mmc_hostname(host->mmc));
++ } 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);
++ }
++ host->single_read_sectors[0] = host->sectors - 65;
++ host->single_read_sectors[1] = host->sectors - 64;
++ host->single_read_sectors[2] = host->sectors - 33;
++ host->single_read_sectors[3] = host->sectors - 32;
++ host->single_read_sectors[4] = host->sectors - 1;
++ host->single_read_sectors[5] = ~0; /* Safety net */
++ }
++
+ host->use_dma = host->have_dma && (data->blocks > host->pio_limit);
+ if (!host->use_dma) {
+ int flags;
+@@ -1246,6 +1278,10 @@ static u32 bcm2835_sdhost_block_irq(stru
+
+ bcm2835_sdhost_finish_data(host);
+ } else {
++ /* Reset the timer */
++ mod_timer(&host->pio_timer,
++ jiffies + host->pio_timeout);
++
+ bcm2835_sdhost_transfer_pio(host);
+
+ /* Reset the timer */
+@@ -1450,8 +1486,8 @@ void bcm2835_sdhost_set_clock(struct bcm
+ host->cdiv = div;
+ bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
+
+- /* Set the timeout to 500ms */
+- bcm2835_sdhost_write(host, host->mmc->actual_clock/2, SDTOUT);
++ /* Set the timeout to 250ms */
++ bcm2835_sdhost_write(host, host->mmc->actual_clock/4, SDTOUT);
+
+ if (host->debug)
+ pr_info("%s: clock=%d -> max_clk=%d, cdiv=%x (actual clock %d)\n",
+@@ -1566,13 +1602,20 @@ static int bcm2835_sdhost_multi_io_quirk
+ reading the final sector of the card as part of a multiple read
+ problematic. Detect that case and shorten the read accordingly.
+ */
+- /* csd.capacity is in weird units - convert to sectors */
+- u32 card_sectors = (card->csd.capacity << (card->csd.read_blkbits - 9));
++ struct bcm2835_host *host;
++
++ host = mmc_priv(card->host);
+
+- if ((direction == MMC_DATA_READ) &&
+- ((blk_pos + blk_size) == card_sectors))
+- blk_size--;
++ if (direction == MMC_DATA_READ)
++ {
++ int i;
++ int sector;
++ for (i = 0; blk_pos > (sector = host->single_read_sectors[i]); i++)
++ continue;
+
++ if ((blk_pos + blk_size) > sector)
++ blk_size = (blk_pos == sector) ? 1 : (sector - blk_pos);
++ }
+ return blk_size;
+ }
+
projects / openwrt.git / blobdiff