mmc: sdhci: work around broken dma boundary behavior
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@yahoo.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index ab17344..2ac0b68 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -679,6 +679,7 @@
host->data = data;
host->data_early = 0;
+ host->data->bytes_xfered = 0;
if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA))
host->flags |= SDHCI_REQ_USE_DMA;
@@ -814,8 +815,9 @@
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);
}
@@ -1558,10 +1560,28 @@
* 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) {