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Commit 3450f5eb authored by Neil Armstrong's avatar Neil Armstrong Committed by Sasha Levin
Browse files

mmc: meson-gx: use memcpy_to/fromio for dram-access-quirk 



commit 103a5348c22c3fca8b96c735a9e353b8a0801842 upstream.

It has been reported that usage of memcpy() to/from an iomem mapping is invalid,
and a recent arm64 memcpy update [1] triggers a memory abort when dram-access-quirk
is used on the G12A/G12B platforms.

This adds a local sg_copy_to_buffer which makes usage of io versions of memcpy
when dram-access-quirk is enabled.

[1] 285133040e6c ("arm64: Import latest memcpy()/memmove() implementation")

Fixes: acdc8e71 ("mmc: meson-gx: add dram-access-quirk")
Reported-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Suggested-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarNeil Armstrong <narmstrong@baylibre.com>
Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20210609150230.9291-1-narmstrong@baylibre.com


Cc: stable@vger.kernel.org
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 48a5449c

drivers/mmc/host/meson-gx-mmc.c

+45 −5
Original line number Diff line number Diff line
@@ -166,6 +166,7 @@ struct meson_host { 


	unsigned int bounce_buf_size;

	void *bounce_buf;

	void __iomem *bounce_iomem_buf;

	dma_addr_t bounce_dma_addr;

	struct sd_emmc_desc *descs;

	dma_addr_t descs_dma_addr;
@@ -737,6 +738,47 @@ static void meson_mmc_desc_chain_transfer(struct mmc_host *mmc, u32 cmd_cfg) 
	writel(start, host->regs + SD_EMMC_START);

}



/* local sg copy to buffer version with _to/fromio usage for dram_access_quirk */

static void meson_mmc_copy_buffer(struct meson_host *host, struct mmc_data *data,

				  size_t buflen, bool to_buffer)

{

	unsigned int sg_flags = SG_MITER_ATOMIC;

	struct scatterlist *sgl = data->sg;

	unsigned int nents = data->sg_len;

	struct sg_mapping_iter miter;

	unsigned int offset = 0;



	if (to_buffer)

		sg_flags |= SG_MITER_FROM_SG;

	else

		sg_flags |= SG_MITER_TO_SG;



	sg_miter_start(&miter, sgl, nents, sg_flags);



	while ((offset < buflen) && sg_miter_next(&miter)) {

		unsigned int len;



		len = min(miter.length, buflen - offset);



		/* When dram_access_quirk, the bounce buffer is a iomem mapping */

		if (host->dram_access_quirk) {

			if (to_buffer)

				memcpy_toio(host->bounce_iomem_buf + offset, miter.addr, len);

			else

				memcpy_fromio(miter.addr, host->bounce_iomem_buf + offset, len);

		} else {

			if (to_buffer)

				memcpy(host->bounce_buf + offset, miter.addr, len);

			else

				memcpy(miter.addr, host->bounce_buf + offset, len);

		}



		offset += len;

	}



	sg_miter_stop(&miter);

}



static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)

{

	struct meson_host *host = mmc_priv(mmc);
@@ -780,8 +822,7 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd) 
		if (data->flags & MMC_DATA_WRITE) {

			cmd_cfg |= CMD_CFG_DATA_WR;

			WARN_ON(xfer_bytes > host->bounce_buf_size);

			sg_copy_to_buffer(data->sg, data->sg_len,

					  host->bounce_buf, xfer_bytes);

			meson_mmc_copy_buffer(host, data, xfer_bytes, true);

			dma_wmb();

		}
@@ -950,8 +991,7 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id) 
	if (meson_mmc_bounce_buf_read(data)) {

		xfer_bytes = data->blksz * data->blocks;

		WARN_ON(xfer_bytes > host->bounce_buf_size);

		sg_copy_from_buffer(data->sg, data->sg_len,

				    host->bounce_buf, xfer_bytes);

		meson_mmc_copy_buffer(host, data, xfer_bytes, false);

	}



	next_cmd = meson_mmc_get_next_command(cmd);
@@ -1179,7 +1219,7 @@ static int meson_mmc_probe(struct platform_device *pdev) 
		 * instead of the DDR memory

		 */

		host->bounce_buf_size = SD_EMMC_SRAM_DATA_BUF_LEN;

		host->bounce_buf = host->regs + SD_EMMC_SRAM_DATA_BUF_OFF;

		host->bounce_iomem_buf = host->regs + SD_EMMC_SRAM_DATA_BUF_OFF;

		host->bounce_dma_addr = res->start + SD_EMMC_SRAM_DATA_BUF_OFF;

	} else {

		/* data bounce buffer */