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@xxxxxxxxxxxxxxxx>
---
drivers/mmc/host/sdhci.c | 43 ++++++++++++++++++++++---------------------
1 file changed, 22 insertions(+), 21 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 078bf43b4aae..9efa7d878731 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 @@ static int sdhci_adma_table_pre(struct sdhci_host *host,
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 @@ static int sdhci_adma_table_pre(struct sdhci_host *host,
* 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 @@ static int sdhci_adma_table_pre(struct sdhci_host *host,
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 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
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);
@@ -2851,15 +2836,29 @@ int sdhci_add_host(struct sdhci_host *host)
* (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;
}
}
@@ -3337,7 +3336,9 @@ void sdhci_remove_host(struct sdhci_host *host, int dead)
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;
--
1.8.3.1
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