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137 lines
4.5 KiB
137 lines
4.5 KiB
From 22a9a698b6cbce7494ea14dce0e784e098c01ecb Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Tue, 19 Jan 2016 17:16:38 +0000
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Subject: [PATCH 134/232] bcm2835-sdhost: Add workaround for odd behaviour on
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some cards
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For reasons not understood, the sdhost driver fails when reading
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sectors very near the end of some SD cards. The problem could
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be related to the similar issue that reading the final sector
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of any card as part of a multiple read never completes, and the
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workaround is an extension of the mechanism introduced to solve
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that problem which ensures those sectors are always read singly.
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---
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drivers/mmc/host/bcm2835-sdhost.c | 61 +++++++++++++++++++++++++++++++++------
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1 file changed, 52 insertions(+), 9 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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@@ -173,6 +173,9 @@ struct bcm2835_host {
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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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+ u32 single_read_sectors[8];
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};
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@@ -277,6 +280,9 @@ static void bcm2835_sdhost_reset_interna
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{
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u32 temp;
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+ if (host->debug)
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+ pr_info("%s: reset\n", mmc_hostname(host->mmc));
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+
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bcm2835_sdhost_set_power(host, false);
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bcm2835_sdhost_write(host, 0, SDCMD);
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@@ -299,6 +305,8 @@ 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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+ host->single_read_sectors[0] = ~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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@@ -309,8 +317,6 @@ static void bcm2835_sdhost_reset(struct
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{
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struct bcm2835_host *host = mmc_priv(mmc);
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unsigned long flags;
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- if (host->debug)
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- pr_info("%s: reset\n", mmc_hostname(mmc));
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spin_lock_irqsave(&host->lock, flags);
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bcm2835_sdhost_reset_internal(host);
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@@ -676,6 +682,32 @@ 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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+ {
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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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+ pr_err("%s: using ext_csd!\n", mmc_hostname(host->mmc));
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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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+ host->single_read_sectors[0] = host->sectors - 65;
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+ host->single_read_sectors[1] = host->sectors - 64;
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+ host->single_read_sectors[2] = host->sectors - 33;
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+ host->single_read_sectors[3] = host->sectors - 32;
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+ host->single_read_sectors[4] = host->sectors - 1;
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+ host->single_read_sectors[5] = ~0; /* Safety net */
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+ }
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+
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host->use_dma = host->have_dma && (data->blocks > host->pio_limit);
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if (!host->use_dma) {
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int flags;
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@@ -1246,6 +1278,10 @@ static u32 bcm2835_sdhost_block_irq(stru
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bcm2835_sdhost_finish_data(host);
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} else {
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+ /* Reset the timer */
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+ mod_timer(&host->pio_timer,
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+ jiffies + host->pio_timeout);
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+
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bcm2835_sdhost_transfer_pio(host);
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/* Reset the timer */
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@@ -1450,8 +1486,8 @@ void bcm2835_sdhost_set_clock(struct bcm
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host->cdiv = div;
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bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
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- /* Set the timeout to 500ms */
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- bcm2835_sdhost_write(host, host->mmc->actual_clock/2, SDTOUT);
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+ /* Set the timeout to 250ms */
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+ bcm2835_sdhost_write(host, host->mmc->actual_clock/4, SDTOUT);
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if (host->debug)
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pr_info("%s: clock=%d -> max_clk=%d, cdiv=%x (actual clock %d)\n",
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@@ -1566,13 +1602,20 @@ static int bcm2835_sdhost_multi_io_quirk
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reading the final sector of the card as part of a multiple read
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problematic. Detect that case and shorten the read accordingly.
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*/
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- /* csd.capacity is in weird units - convert to sectors */
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- u32 card_sectors = (card->csd.capacity << (card->csd.read_blkbits - 9));
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+ struct bcm2835_host *host;
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+
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+ host = mmc_priv(card->host);
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- if ((direction == MMC_DATA_READ) &&
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- ((blk_pos + blk_size) == card_sectors))
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- blk_size--;
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+ if (direction == MMC_DATA_READ)
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+ {
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+ int i;
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+ int sector;
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+ for (i = 0; blk_pos > (sector = host->single_read_sectors[i]); i++)
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+ continue;
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+ if ((blk_pos + blk_size) > sector)
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+ blk_size = (blk_pos == sector) ? 1 : (sector - blk_pos);
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+ }
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return blk_size;
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}
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