linux-kernel - [PATCH RFC 2/2] mmc: meson-gx: use sg_copy_to/from

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Message-Id: <20210628123411.119778-3-narmstrong@baylibre.com>
Date:   Mon, 28 Jun 2021 14:34:11 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     jgg@...pe.ca, leon@...nel.org, m.szyprowski@...sung.com,
        robin.murphy@....com, ulf.hansson@...aro.org
Cc:     torvalds@...ux-foundation.org, khilman@...libre.com,
        jbrunet@...libre.com, linux-mmc@...r.kernel.org,
        linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Neil Armstrong <narmstrong@...libre.com>
Subject: [PATCH RFC 2/2] mmc: meson-gx: use sg_copy_to/from_io instead of local version

Use the proper sg_copy_to_io & sg_copy_from_io instead of having a local
sg_copy_buffer variant to handle the I/O mapped buffer case.

Cc: Robin Murphy <robin.murphy@....com>
Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
---
 drivers/mmc/host/meson-gx-mmc.c | 53 +++++++--------------------------
 1 file changed, 10 insertions(+), 43 deletions(-)

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index 3f28eb4d17fe..c13436efb414 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -746,47 +746,6 @@ 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);
@@ -830,7 +789,12 @@ 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);
-			meson_mmc_copy_buffer(host, data, xfer_bytes, true);
+			if (host->dram_access_quirk)
+				sg_copy_to_io(data->sg, data->sg_len,
+					      host->bounce_iomem_buf, xfer_bytes);
+			else
+				sg_copy_to_buffer(data->sg, data->sg_len,
+						  host->bounce_buf, xfer_bytes);
 			dma_wmb();
 		}
 
@@ -999,7 +963,10 @@ 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);
-		meson_mmc_copy_buffer(host, data, xfer_bytes, false);
+		if (host->dram_access_quirk)
+			sg_copy_from_io(data->sg, data->sg_len, host->bounce_iomem_buf, xfer_bytes);
+		else
+			sg_copy_from_buffer(data->sg, data->sg_len, host->bounce_buf, xfer_bytes);
 	}
 
 	next_cmd = meson_mmc_get_next_command(cmd);
-- 
2.25.1