mmc: sdhci: convert ADMA descriptors to a coherent allocation
Rather than using the streaming API, use the coherent allocator to
provide this memory, thereby eliminating cache flushing of it each
time we map and unmap it. This results in a 7.5% increase in
transfer speed with a UHS-1 card operating in 3.3v mode at a clock
of 49.5MHz.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Markus Pargmann <mpa@pengutronix.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 4f878bc..fd20e89 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -44,6 +44,8 @@
#define MAX_TUNING_LOOP 40
+#define ADMA_SIZE ((128 * 2 + 1) * 4)
+
static unsigned int debug_quirks = 0;
static unsigned int debug_quirks2;
@@ -481,11 +483,6 @@
else
direction = DMA_TO_DEVICE;
- /*
- * The ADMA descriptor table is mapped further down as we
- * need to fill it with data first.
- */
-
host->align_addr = dma_map_single(mmc_dev(host->mmc),
host->align_buffer, 128 * 4, direction);
if (dma_mapping_error(mmc_dev(host->mmc), host->align_addr))
@@ -546,7 +543,7 @@
* If this triggers then we have a calculation bug
* somewhere. :/
*/
- WARN_ON((desc - host->adma_desc) > (128 * 2 + 1) * 4);
+ WARN_ON((desc - host->adma_desc) > ADMA_SIZE);
}
if (host->quirks & SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC) {
@@ -574,17 +571,8 @@
host->align_addr, 128 * 4, direction);
}
- host->adma_addr = dma_map_single(mmc_dev(host->mmc),
- host->adma_desc, (128 * 2 + 1) * 4, DMA_TO_DEVICE);
- if (dma_mapping_error(mmc_dev(host->mmc), host->adma_addr))
- goto unmap_entries;
- BUG_ON(host->adma_addr & 0x3);
-
return 0;
-unmap_entries:
- dma_unmap_sg(mmc_dev(host->mmc), data->sg,
- data->sg_len, direction);
unmap_align:
dma_unmap_single(mmc_dev(host->mmc), host->align_addr,
128 * 4, direction);
@@ -609,9 +597,6 @@
else
direction = DMA_TO_DEVICE;
- dma_unmap_single(mmc_dev(host->mmc), host->adma_addr,
- (128 * 2 + 1) * 4, DMA_TO_DEVICE);
-
dma_unmap_single(mmc_dev(host->mmc), host->align_addr,
128 * 4, direction);
@@ -2856,15 +2841,29 @@
* (128) and potentially one alignment transfer for
* each of those entries.
*/
- host->adma_desc = kmalloc((128 * 2 + 1) * 4, GFP_KERNEL);
+ host->adma_desc = dma_alloc_coherent(mmc_dev(host->mmc),
+ ADMA_SIZE, &host->adma_addr,
+ GFP_KERNEL);
host->align_buffer = kmalloc(128 * 4, GFP_KERNEL);
if (!host->adma_desc || !host->align_buffer) {
- kfree(host->adma_desc);
+ dma_free_coherent(mmc_dev(host->mmc), ADMA_SIZE,
+ host->adma_desc, host->adma_addr);
kfree(host->align_buffer);
pr_warning("%s: Unable to allocate ADMA "
"buffers. Falling back to standard DMA.\n",
mmc_hostname(mmc));
host->flags &= ~SDHCI_USE_ADMA;
+ host->adma_desc = NULL;
+ host->align_buffer = NULL;
+ } else if (host->adma_addr & 3) {
+ pr_warning("%s: unable to allocate aligned ADMA descriptor\n",
+ mmc_hostname(mmc));
+ host->flags &= ~SDHCI_USE_ADMA;
+ dma_free_coherent(mmc_dev(host->mmc), ADMA_SIZE,
+ host->adma_desc, host->adma_addr);
+ kfree(host->align_buffer);
+ host->adma_desc = NULL;
+ host->align_buffer = NULL;
}
}
@@ -3342,7 +3341,9 @@
regulator_put(host->vqmmc);
}
- kfree(host->adma_desc);
+ if (host->adma_desc)
+ dma_free_coherent(mmc_dev(host->mmc), ADMA_SIZE,
+ host->adma_desc, host->adma_addr);
kfree(host->align_buffer);
host->adma_desc = NULL;