mmc: meson-gx: use an intermediate buffer for dram_access_quirk

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

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

@@ -747,50 +747,29 @@ static void meson_mmc_desc_chain_transfer(struct mmc_host *mmc, u32 cmd_cfg)
 }
 
 /* local sg copy for dram_access_quirk */
-static void meson_mmc_copy_buffer(struct meson_host *host, struct mmc_data *data,
-				  size_t buflen, bool to_buffer)
+static void meson_mmc_copy_buffer(struct meson_host *host, 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);
+	unsigned int buf_offset = 0;
+	unsigned int left;
+	u32 *buf = host->bounce_buf;
 
-	while ((offset < buflen) && sg_miter_next(&miter)) {
-		unsigned int buf_offset = 0;
-		unsigned int len, left;
-		u32 *buf = miter.addr;
+	left = buflen;
 
-		len = min(miter.length, buflen - offset);
-		left = len;
+	if (to_buffer) {
+		do {
+			writel(*buf++, host->bounce_iomem_buf + buf_offset);
 
-		if (to_buffer) {
-			do {
-				writel(*buf++, host->bounce_iomem_buf + offset + buf_offset);
-
-				buf_offset += 4;
-				left -= 4;
-			} while (left);
-		} else {
-			do {
-				*buf++ = readl(host->bounce_iomem_buf + offset + buf_offset);
-
-				buf_offset += 4;
-				left -= 4;
-			} while (left);
-		}
+			buf_offset += 4;
+			left -= 4;
+		} while (left);
+	} else {
+		do {
+			*buf++ = readl(host->bounce_iomem_buf + buf_offset);
 
-		offset += len;
+			buf_offset += 4;
+			left -= 4;
+		} while (left);
 	}
-
-	sg_miter_stop(&miter);
 }
 
 static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
@@ -836,11 +815,10 @@ 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);
 			if (host->dram_access_quirk)
-				meson_mmc_copy_buffer(host, data, xfer_bytes, true);
-			else
-				sg_copy_to_buffer(data->sg, data->sg_len,
-						  host->bounce_buf, xfer_bytes);
+				meson_mmc_copy_buffer(host, xfer_bytes, true);
 			dma_wmb();
 		}
 
@@ -859,43 +837,12 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
 	writel(cmd->arg, host->regs + SD_EMMC_CMD_ARG);
 }
 
-static int meson_mmc_validate_dram_access(struct mmc_host *mmc, struct mmc_data *data)
-{
-	struct scatterlist *sg;
-	int i;
-
-	/* Reject request if any element offset or size is not 32bit aligned */
-	for_each_sg(data->sg, sg, data->sg_len, i) {
-		if (!IS_ALIGNED(sg->offset, sizeof(u32)) ||
-		    !IS_ALIGNED(sg->length, sizeof(u32))) {
-			dev_err(mmc_dev(mmc), "unaligned sg offset %u len %u\n",
-				data->sg->offset, data->sg->length);
-			return -EINVAL;
-		}
-	}
-
-	return 0;
-}
-
 static void meson_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq)
 {
 	struct meson_host *host = mmc_priv(mmc);
 	bool needs_pre_post_req = mrq->data &&
 			!(mrq->data->host_cookie & SD_EMMC_PRE_REQ_DONE);
 
-	/*
-	 * The memory at the end of the controller used as bounce buffer for
-	 * the dram_access_quirk only accepts 32bit read/write access,
-	 * check the aligment and length of the data before starting the request.
-	 */
-	if (host->dram_access_quirk && mrq->data) {
-		mrq->cmd->error = meson_mmc_validate_dram_access(mmc, mrq->data);
-		if (mrq->cmd->error) {
-			mmc_request_done(mmc, mrq);
-			return;
-		}
-	}
-
 	if (needs_pre_post_req) {
 		meson_mmc_get_transfer_mode(mmc, mrq);
 		if (!meson_mmc_desc_chain_mode(mrq->data))
@@ -1040,11 +987,10 @@ 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);
+		sg_copy_from_buffer(data->sg, data->sg_len,
+				    host->bounce_buf, xfer_bytes);
 		if (host->dram_access_quirk)
-			meson_mmc_copy_buffer(host, data, xfer_bytes, false);
-		else
-			sg_copy_from_buffer(data->sg, data->sg_len,
-					    host->bounce_buf, xfer_bytes);
+			meson_mmc_copy_buffer(host, xfer_bytes, false);
 	}
 
 	next_cmd = meson_mmc_get_next_command(cmd);
@@ -1266,6 +1212,7 @@ static int meson_mmc_probe(struct platform_device *pdev)
 		host->bounce_buf_size = SD_EMMC_SRAM_DATA_BUF_LEN;
 		host->bounce_iomem_buf = host->regs + SD_EMMC_SRAM_DATA_BUF_OFF;
 		host->bounce_dma_addr = res->start + SD_EMMC_SRAM_DATA_BUF_OFF;
+		host->bounce_buf = devm_kmalloc(host->dev, host->bounce_buf_size, GFP_KERNEL);
 	} else {
 		/* data bounce buffer */
 		host->bounce_buf_size = mmc->max_req_size;