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mmc: sdhci: convert ADMA descriptors to a coherent allocation

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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>
This commit is contained in:
Russell King 2014-04-25 12:58:34 +01:00 committed by Chris Ball
parent de0b65a786
commit d1e49f77d7
1 changed files with 22 additions and 21 deletions
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43
drivers/mmc/host/sdhci.c
View file

@ -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);
@ -2856,15 +2841,29 @@ 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;
}
}
@ -3342,7 +3341,9 @@ 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;