Some SD host controllers (noticed on an integrated JMicron SD reader on an HP Pavilion dv5-1250eo laptop) don't update the dma address register before signaling a dma interrupt due to a dma boundary. Update the register manually to the next boundary (by default 512KiB), at which the transfer stopped. As long as each transfer is at most 512KiB in size (guaranteed by a BUG_ON in sdhci_prepare_data()) and the boundary is kept at the default value, this fix is needed at most once per transfer. Smaller boundaries are taken care of by counting the transferred bytes. Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=28462 Signed-off-by: Mikko Vinni <mmvinni@xxxxxxxxx> --- This is alternative to http://article.gmane.org/gmane.linux.kernel.mmc/6497 The main concern about the original patch was that it won't work for if the boundary is made smaller and a large transfer would cross the boundary twice. With this version this is taken care of by re-using the bytes_xfered field from struct mmc_data. Grepping through the code revealed no other uses of bytes_xfered in host/sdhci.c except after the transfer is complete. This patch has been tested with at least the boundary sizes 4, 8, 32, and 512KiB. The mmc-test tests all passed when tested with 32KiB. This is on the "broken" controller. No other card readers were tested so far. The added debug output looks like this: sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00000008 sdhci [sdhci_data_irq()]: mmc0: DMA base 0x00100000, transferred 0x008000 bytes, next 0x00108000 sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00000008 sdhci [sdhci_data_irq()]: mmc0: DMA base 0x00100000, transferred 0x010000 bytes, next 0x00110000 sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00000008 sdhci [sdhci_data_irq()]: mmc0: DMA base 0x00100000, transferred 0x018000 bytes, next 0x00118000 sdhci [sdhci_irq()]: *** mmc0 got interrupt: 0x00000008 sdhci [sdhci_data_irq()]: mmc0: DMA base 0x00100000, transferred 0x020000 bytes, next 0x00120000 In my opinion this is more risky than the original patch because this will affect the behavior on all controllers that use sdhci, and not just on those ones that don't update SDHCI_DMA_ADDRESS themselves. Comments welcome! drivers/mmc/host/sdhci.c | 30 +++++++++++++++++++++++++----- drivers/mmc/host/sdhci.h | 6 ++++++ 2 files changed, 31 insertions(+), 5 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 9e15f41..0319903 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -669,6 +669,7 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data) host->data = data; host->data_early = 0; + host->data->bytes_xfered = 0; count = sdhci_calc_timeout(host, data); sdhci_writeb(host, count, SDHCI_TIMEOUT_CONTROL); @@ -807,8 +808,9 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data) sdhci_set_transfer_irqs(host); - /* We do not handle DMA boundaries, so set it to max (512 KiB) */ - sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, data->blksz), SDHCI_BLOCK_SIZE); + /* Set the DMA boundary value and block size */ + sdhci_writew(host, SDHCI_MAKE_BLKSZ(SDHCI_DEFAULT_BOUNDARY_ARG, + data->blksz), SDHCI_BLOCK_SIZE); sdhci_writew(host, data->blocks, SDHCI_BLOCK_COUNT); } @@ -1544,10 +1546,28 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask) * We currently don't do anything fancy with DMA * boundaries, but as we can't disable the feature * we need to at least restart the transfer. + * + * According to the spec sdhci_readl(host, SDHCI_DMA_ADDRESS) + * should return a valid address to continue from, but as + * some controllers are faulty, don't trust them. */ - if (intmask & SDHCI_INT_DMA_END) - sdhci_writel(host, sdhci_readl(host, SDHCI_DMA_ADDRESS), - SDHCI_DMA_ADDRESS); + if (intmask & SDHCI_INT_DMA_END) { + u32 dmastart, dmanow; + dmastart = sg_dma_address(host->data->sg); + dmanow = dmastart + host->data->bytes_xfered; + /* + * Force update to the next DMA block boundary. + */ + dmanow = (dmanow & + ~(SDHCI_DEFAULT_BOUNDARY_SIZE - 1)) + + SDHCI_DEFAULT_BOUNDARY_SIZE; + host->data->bytes_xfered = dmanow - dmastart; + DBG("%s: DMA base 0x%08x, transferred 0x%06x bytes," + " next 0x%08x\n", + mmc_hostname(host->mmc), dmastart, + host->data->bytes_xfered, dmanow); + sdhci_writel(host, dmanow, SDHCI_DMA_ADDRESS); + } if (intmask & SDHCI_INT_DATA_END) { if (host->cmd) { diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index 25e8bde..85750a9 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -202,6 +202,12 @@ #define SDHCI_MAX_DIV_SPEC_200 256 #define SDHCI_MAX_DIV_SPEC_300 2046 +/* + * Host SDMA buffer boundary. Valid values from 4K to 512K in powers of 2. + */ +#define SDHCI_DEFAULT_BOUNDARY_SIZE (512 * 1024) +#define SDHCI_DEFAULT_BOUNDARY_ARG (ilog2(SDHCI_DEFAULT_BOUNDARY_SIZE) - 12) + struct sdhci_ops { #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS u32 (*read_l)(struct sdhci_host *host, int reg); -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
