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Commit 9c21b8ee authored by Russell King's avatar Russell King Committed by Venkat Gopalakrishnan
Browse files

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.

CRs-fixed: 684185
Change-Id: I82aae6264db1ebfb87badbb223893b066ad53652
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Tested-by: default avatarMarkus Pargmann <mpa@pengutronix.de>
Tested-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarChris Ball <chris@printf.net>
Git-commit: d1e49f77d7c7b75fdc022e1d46c1549bbc91c5b7
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[venkatg@codeaurora.org: use adma_desc_sz for ADMA_SIZE & align_bytes - 1
for alignment check]
Signed-off-by: default avatarVenkat Gopalakrishnan <venkatg@codeaurora.org>
parent bacf292c

drivers/mmc/host/sdhci.c

+19 −22
Original line number Diff line number Diff line
@@ -621,10 +621,6 @@ 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,

					  host->align_buf_sz,
@@ -726,19 +722,8 @@ static int sdhci_adma_table_pre(struct sdhci_host *host, 
					   direction);

	}



	host->adma_addr = dma_map_single(mmc_dev(host->mmc),

					 host->adma_desc,

					 host->adma_desc_sz,

					 DMA_TO_DEVICE);

	if (dma_mapping_error(mmc_dev(host->mmc), host->adma_addr))

		goto unmap_entries;

	BUG_ON(host->adma_addr & (host->align_bytes - 1));



	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,

			 host->align_buf_sz, direction);
@@ -762,9 +747,6 @@ 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,

			 host->adma_desc_sz, DMA_TO_DEVICE);



	dma_unmap_single(mmc_dev(host->mmc), host->align_addr,

			 host->align_buf_sz, direction);
@@ -3522,17 +3504,30 @@ int sdhci_add_host(struct sdhci_host *host) 


		pr_debug("%s: %s: dma_desc_size: %d\n",

			mmc_hostname(host->mmc), __func__, host->adma_desc_sz);

		host->adma_desc = kmalloc(host->adma_desc_sz,

		host->adma_desc = dma_alloc_coherent(mmc_dev(host->mmc),

						     host->adma_desc_sz, &host->adma_addr,

						     GFP_KERNEL);

		host->align_buffer = kmalloc(host->align_buf_sz,

					     GFP_KERNEL);

		if (!host->adma_desc || !host->align_buffer) {

			kfree(host->adma_desc);

			dma_free_coherent(mmc_dev(host->mmc), host->adma_desc_sz,

					  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 & (host->align_bytes - 1)) {

			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), host->adma_desc_sz,

					  host->adma_desc, host->adma_addr);

			kfree(host->align_buffer);

			host->adma_desc = NULL;

			host->align_buffer = NULL;

		}

	}
@@ -4043,7 +4038,9 @@ 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), host->adma_desc_sz,

				  host->adma_desc, host->adma_addr);

	kfree(host->align_buffer);



	host->adma_desc = NULL;