Switch the driver from using a linearized bounce buffer to descriptor
chain mode. This drastically improves performance.
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
Remark:
- This patch depends on "mmc: sdio: fix alignment issue in struct sdio_func"
having been applied before, else SDIO is broken.
---
drivers/mmc/host/meson-gx-mmc.c | 143 ++++++++++++++++++++++++----------------
1 file changed, 87 insertions(+), 56 deletions(-)
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index 0036680b..1a64cb91 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -109,8 +109,16 @@
#define SD_EMMC_CMD_TIMEOUT 1024 /* in ms */
#define SD_EMMC_CMD_TIMEOUT_DATA 4096 /* in ms */
#define SD_EMMC_CFG_CMD_GAP 16 /* in clock cycles */
+#define SD_EMMC_DESC_BUF_LEN PAGE_SIZE
#define MUX_CLK_NUM_PARENTS 2
+struct sd_emmc_desc {
+ u32 cmd_cfg;
+ u32 cmd_arg;
+ u32 cmd_data;
+ u32 cmd_resp;
+};
+
struct meson_host {
struct device *dev;
struct mmc_host *mmc;
@@ -126,20 +134,12 @@ struct meson_host {
struct clk_divider cfg_div;
struct clk *cfg_div_clk;
- unsigned int bounce_buf_size;
- void *bounce_buf;
- dma_addr_t bounce_dma_addr;
+ struct sd_emmc_desc *descs;
+ dma_addr_t descs_dma_addr;
bool vqmmc_enabled;
};
-struct sd_emmc_desc {
- u32 cmd_cfg;
- u32 cmd_arg;
- u32 cmd_data;
- u32 cmd_resp;
-};
-
#define CMD_CFG_LENGTH_MASK GENMASK(8, 0)
#define CMD_CFG_BLOCK_MODE BIT(9)
#define CMD_CFG_R1B BIT(10)
@@ -186,6 +186,31 @@ static struct mmc_command *meson_mmc_get_next_command(struct mmc_command *cmd)
return NULL;
}
+static void meson_mmc_pre_req(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+ struct mmc_data *data = mrq->data;
+
+ if (!data)
+ return;
+
+ data->host_cookie = true;
+
+ data->sg_count = dma_map_sg(mmc_dev(mmc), data->sg, data->sg_len,
+ mmc_get_dma_dir(data));
+ if (!data->sg_count)
+ dev_err(mmc_dev(mmc), "dma_map_sg failed");
+}
+
+static void meson_mmc_post_req(struct mmc_host *mmc, struct mmc_request *mrq,
+ int err)
+{
+ struct mmc_data *data = mrq->data;
+
+ if (data && data->sg_count)
+ dma_unmap_sg(mmc_dev(mmc), data->sg, data->sg_len,
+ mmc_get_dma_dir(data));
+}
+
static int meson_mmc_clk_set(struct meson_host *host, unsigned long clk_rate)
{
struct mmc_host *mmc = host->mmc;
@@ -476,9 +501,11 @@ static void meson_mmc_set_response_bits(struct mmc_command *cmd, u32 *cmd_cfg)
static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
{
struct meson_host *host = mmc_priv(mmc);
+ struct sd_emmc_desc *desc = host->descs;
struct mmc_data *data = cmd->data;
- u32 cmd_cfg = 0, cmd_data = 0;
- unsigned int xfer_bytes = 0;
+ u32 cfg, cmd_cfg = 0;
+ struct scatterlist *sg;
+ int i;
/* Setup descriptors */
dma_rmb();
@@ -490,57 +517,68 @@ static void meson_mmc_start_cmd(struct mmc_host *mmc, struct mmc_command *cmd)
/* data? */
if (data) {
+ data->bytes_xfered = 0;
cmd_cfg |= CMD_CFG_DATA_IO;
cmd_cfg |= FIELD_PREP(CMD_CFG_TIMEOUT_MASK,
ilog2(meson_mmc_get_timeout_msecs(data)));
+ if (data->flags & MMC_DATA_WRITE)
+ cmd_cfg |= CMD_CFG_DATA_WR;
if (data->blocks > 1) {
cmd_cfg |= CMD_CFG_BLOCK_MODE;
- cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK,
- data->blocks);
meson_mmc_set_blksz(mmc, data->blksz);
- } else {
- cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK, data->blksz);
}
- data->bytes_xfered = 0;
- xfer_bytes = data->blksz * data->blocks;
- 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);
- dma_wmb();
- }
+ for_each_sg(data->sg, sg, data->sg_count, i) {
+ unsigned int len = sg_dma_len(sg);
+
+ /* check proper alignment for 64 bit DMA */
+ WARN_ON(sg_dma_address(sg) & 0x7);
- cmd_data = host->bounce_dma_addr & CMD_DATA_MASK;
+ if (data->blocks > 1)
+ len /= data->blksz;
+
+ desc[i].cmd_cfg = cmd_cfg;
+ desc[i].cmd_cfg |= FIELD_PREP(CMD_CFG_LENGTH_MASK, len);
+ if (i > 0)
+ desc[i].cmd_cfg |= CMD_CFG_NO_CMD;
+ desc[i].cmd_arg = cmd->arg;
+ desc[i].cmd_resp = 0;
+ desc[i].cmd_data = sg_dma_address(sg);
+ }
+ desc[data->sg_count - 1].cmd_cfg |= CMD_CFG_END_OF_CHAIN;
} else {
cmd_cfg |= FIELD_PREP(CMD_CFG_TIMEOUT_MASK,
ilog2(SD_EMMC_CMD_TIMEOUT));
+ cmd_cfg |= CMD_CFG_END_OF_CHAIN;
+ desc[0].cmd_cfg = cmd_cfg;
+ desc[0].cmd_arg = cmd->arg;
+ desc[0].cmd_resp = 0;
+ desc[0].cmd_data = 0;
}
host->cmd = cmd;
- /* Last descriptor */
- cmd_cfg |= CMD_CFG_END_OF_CHAIN;
- writel(cmd_cfg, host->regs + SD_EMMC_CMD_CFG);
- writel(cmd_data, host->regs + SD_EMMC_CMD_DAT);
- writel(0, host->regs + SD_EMMC_CMD_RSP);
wmb(); /* ensure descriptor is written before kicked */
- writel(cmd->arg, host->regs + SD_EMMC_CMD_ARG);
+ cfg = host->descs_dma_addr | START_DESC_BUSY;
+ writel(cfg, host->regs + SD_EMMC_START);
}
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;
+
+ if (needs_pre_post_req)
+ meson_mmc_pre_req(mmc, mrq);
/* Stop execution */
writel(0, host->regs + SD_EMMC_START);
- if (mrq->sbc)
- meson_mmc_start_cmd(mmc, mrq->sbc);
- else
- meson_mmc_start_cmd(mmc, mrq->cmd);
+ meson_mmc_start_cmd(mmc, mrq->sbc ?: mrq->cmd);
+
+ if (needs_pre_post_req)
+ meson_mmc_post_req(mmc, mrq, 0);
}
static void meson_mmc_read_resp(struct mmc_host *mmc, struct mmc_command *cmd)
@@ -618,7 +656,9 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
if (status & (IRQ_END_OF_CHAIN | IRQ_RESP_STATUS)) {
if (data && !cmd->error)
data->bytes_xfered = data->blksz * data->blocks;
- ret = IRQ_WAKE_THREAD;
+
+ if (meson_mmc_get_next_command(cmd))
+ ret = IRQ_WAKE_THREAD;
} else {
dev_warn(host->dev, "Unknown IRQ! status=0x%04x: MMC CMD%u arg=0x%08x flags=0x%08x stop=%d\n",
status, cmd->opcode, cmd->arg,
@@ -648,20 +688,10 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
{
struct meson_host *host = dev_id;
struct mmc_command *next_cmd, *cmd = host->cmd;
- struct mmc_data *data;
- unsigned int xfer_bytes;
if (WARN_ON(!cmd))
return IRQ_NONE;
- data = cmd->data;
- if (data && data->flags & MMC_DATA_READ) {
- 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);
- }
-
next_cmd = meson_mmc_get_next_command(cmd);
if (next_cmd)
meson_mmc_start_cmd(host->mmc, next_cmd);
@@ -701,6 +731,8 @@ static const struct mmc_host_ops meson_mmc_ops = {
.request = meson_mmc_request,
.set_ios = meson_mmc_set_ios,
.get_cd = meson_mmc_get_cd,
+ .pre_req = meson_mmc_pre_req,
+ .post_req = meson_mmc_post_req,
};
static int meson_mmc_probe(struct platform_device *pdev)
@@ -781,14 +813,13 @@ static int meson_mmc_probe(struct platform_device *pdev)
mmc->caps |= MMC_CAP_CMD23;
mmc->max_blk_count = CMD_CFG_LENGTH_MASK;
mmc->max_req_size = mmc->max_blk_count * mmc->max_blk_size;
+ mmc->max_segs = SD_EMMC_DESC_BUF_LEN / sizeof(struct sd_emmc_desc);
+ mmc->max_seg_size = mmc->max_req_size;
- /* data bounce buffer */
- host->bounce_buf_size = mmc->max_req_size;
- host->bounce_buf =
- dma_alloc_coherent(host->dev, host->bounce_buf_size,
- &host->bounce_dma_addr, GFP_KERNEL);
- if (host->bounce_buf == NULL) {
- dev_err(host->dev, "Unable to map allocate DMA bounce buffer.\n");
+ host->descs = dma_alloc_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
+ &host->descs_dma_addr, GFP_KERNEL);
+ if (!host->descs) {
+ dev_err(host->dev, "Allocating DMA descriptor buffer failed\n");
ret = -ENOMEM;
goto err_div_clk;
}
@@ -816,8 +847,8 @@ static int meson_mmc_remove(struct platform_device *pdev)
/* disable interrupts */
writel(0, host->regs + SD_EMMC_IRQ_EN);
- dma_free_coherent(host->dev, host->bounce_buf_size,
- host->bounce_buf, host->bounce_dma_addr);
+ dma_free_coherent(host->dev, SD_EMMC_DESC_BUF_LEN,
+ host->descs, host->descs_dma_addr);
clk_disable_unprepare(host->cfg_div_clk);
clk_disable_unprepare(host->core_clk);
--
2.12.1
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