Throughput tests have shown the sunxi_mmc driver to take over 10s to
read 10MB from a fast eMMC device due to excessive delays in polling
loops.
This commit restructures the main polling loops to use get_timer(...)
to determine whether a (millisecond) timeout has expired. We choose
not to use the wait_bit function, as we don't need interruptability
with ctrl-c and have at least one case where two bits (one for an
error condition and another one for completion) need to be read and
using wait_bit would have not added to the clarity.
The observed speedup in testing on a A31 is greater than 10x (e.g. a
10MB write decreases from 9.302s to 0.884s).
X-Affected-platforms: A31-uQ7, A80-Q7, A64-uQ7
Signed-off-by: Philipp Tomsich <philipp.toms...@theobroma-systems.com>
---
drivers/mmc/sunxi_mmc.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/drivers/mmc/sunxi_mmc.c b/drivers/mmc/sunxi_mmc.c
index d3106db..46abe4a 100644
--- a/drivers/mmc/sunxi_mmc.c
+++ b/drivers/mmc/sunxi_mmc.c
@@ -180,22 +180,22 @@ static int mmc_clk_io_on(int sdc_no)
static int mmc_update_clk(struct mmc *mmc)
{
struct sunxi_mmc_host *mmchost = mmc->priv;
unsigned int cmd;
unsigned timeout_msecs = 2000;
+ unsigned long start = get_timer(0);
cmd = SUNXI_MMC_CMD_START |
SUNXI_MMC_CMD_UPCLK_ONLY |
SUNXI_MMC_CMD_WAIT_PRE_OVER;
writel(cmd, &mmchost->reg->cmd);
while (readl(&mmchost->reg->cmd) & SUNXI_MMC_CMD_START) {
- if (!timeout_msecs--)
+ if (get_timer(start) > timeout_msecs)
return -1;
- udelay(1000);
}
/* clock update sets various irq status bits, clear these */
writel(readl(&mmchost->reg->rint), &mmchost->reg->rint);
return 0;
}
@@ -265,161 +265,165 @@ static int sunxi_mmc_core_init(struct mmc *mmc)
static int mmc_trans_data_by_cpu(struct mmc *mmc, struct mmc_data *data)
{
struct sunxi_mmc_host *mmchost = mmc->priv;
const int reading = !!(data->flags & MMC_DATA_READ);
const uint32_t status_bit = reading ? SUNXI_MMC_STATUS_FIFO_EMPTY :
SUNXI_MMC_STATUS_FIFO_FULL;
unsigned i;
unsigned *buff = (unsigned int *)(reading ? data->dest : data->src);
unsigned byte_cnt = data->blocksize * data->blocks;
- unsigned timeout_usecs = (byte_cnt >> 8) * 1000;
- if (timeout_usecs < 2000000)
- timeout_usecs = 2000000;
+ unsigned timeout_msecs = byte_cnt >> 8;
+ unsigned long start;
+
+ if (timeout_msecs < 2000)
+ timeout_msecs = 2000;
/* Always read / write data through the CPU */
setbits_le32(&mmchost->reg->gctrl, SUNXI_MMC_GCTRL_ACCESS_BY_AHB);
+ start = get_timer(0);
+
for (i = 0; i < (byte_cnt >> 2); i++) {
while (readl(&mmchost->reg->status) & status_bit) {
- if (!timeout_usecs--)
+ if (get_timer(start) > timeout_msecs)
return -1;
- udelay(1);
}
if (reading)
buff[i] = readl(&mmchost->reg->fifo);
else
writel(buff[i], &mmchost->reg->fifo);
}
return 0;
}
static int mmc_rint_wait(struct mmc *mmc, unsigned int timeout_msecs,
unsigned int done_bit, const char *what)
{
struct sunxi_mmc_host *mmchost = mmc->priv;
unsigned int status;
+ unsigned long start = get_timer(0);
do {
status = readl(&mmchost->reg->rint);
- if (!timeout_msecs-- ||
+ if ((get_timer(start) > timeout_msecs) ||
(status & SUNXI_MMC_RINT_INTERRUPT_ERROR_BIT)) {
debug("%s timeout %x\n", what,
status & SUNXI_MMC_RINT_INTERRUPT_ERROR_BIT);
return -ETIMEDOUT;
}
- udelay(1000);
} while (!(status & done_bit));
return 0;
}
static int sunxi_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
struct mmc_data *data)
{
struct sunxi_mmc_host *mmchost = mmc->priv;
unsigned int cmdval = SUNXI_MMC_CMD_START;
unsigned int timeout_msecs;
int error = 0;
unsigned int status = 0;
unsigned int bytecnt = 0;
if (mmchost->fatal_err)
return -1;
if (cmd->resp_type & MMC_RSP_BUSY)
debug("mmc cmd %d check rsp busy\n", cmd->cmdidx);
if (cmd->cmdidx == 12)
return 0;
if (!cmd->cmdidx)
cmdval |= SUNXI_MMC_CMD_SEND_INIT_SEQ;
if (cmd->resp_type & MMC_RSP_PRESENT)
cmdval |= SUNXI_MMC_CMD_RESP_EXPIRE;
if (cmd->resp_type & MMC_RSP_136)
cmdval |= SUNXI_MMC_CMD_LONG_RESPONSE;
if (cmd->resp_type & MMC_RSP_CRC)
cmdval |= SUNXI_MMC_CMD_CHK_RESPONSE_CRC;
if (data) {
if ((u32)(long)data->dest & 0x3) {
error = -1;
goto out;
}
cmdval |= SUNXI_MMC_CMD_DATA_EXPIRE|SUNXI_MMC_CMD_WAIT_PRE_OVER;
if (data->flags & MMC_DATA_WRITE)
cmdval |= SUNXI_MMC_CMD_WRITE;
if (data->blocks > 1)
cmdval |= SUNXI_MMC_CMD_AUTO_STOP;
writel(data->blocksize, &mmchost->reg->blksz);
writel(data->blocks * data->blocksize, &mmchost->reg->bytecnt);
}
debug("mmc %d, cmd %d(0x%08x), arg 0x%08x\n", mmchost->mmc_no,
cmd->cmdidx, cmdval | cmd->cmdidx, cmd->cmdarg);
writel(cmd->cmdarg, &mmchost->reg->arg);
if (!data)
writel(cmdval | cmd->cmdidx, &mmchost->reg->cmd);
/*
* transfer data and check status
* STATREG[2] : FIFO empty
* STATREG[3] : FIFO full
*/
if (data) {
int ret = 0;
bytecnt = data->blocksize * data->blocks;
debug("trans data %d bytes\n", bytecnt);
writel(cmdval | cmd->cmdidx, &mmchost->reg->cmd);
ret = mmc_trans_data_by_cpu(mmc, data);
if (ret) {
error = readl(&mmchost->reg->rint) & \
SUNXI_MMC_RINT_INTERRUPT_ERROR_BIT;
error = -ETIMEDOUT;
goto out;
}
}
error = mmc_rint_wait(mmc, 1000, SUNXI_MMC_RINT_COMMAND_DONE, "cmd");
if (error)
goto out;
if (data) {
timeout_msecs = 120;
debug("cacl timeout %x msec\n", timeout_msecs);
error = mmc_rint_wait(mmc, timeout_msecs,
data->blocks > 1 ?
SUNXI_MMC_RINT_AUTO_COMMAND_DONE :
SUNXI_MMC_RINT_DATA_OVER,
"data");
if (error)
goto out;
}
if (cmd->resp_type & MMC_RSP_BUSY) {
+ unsigned long start = get_timer(0);
timeout_msecs = 2000;
+
do {
status = readl(&mmchost->reg->status);
- if (!timeout_msecs--) {
+ if (get_timer(start) > timeout_msecs) {
debug("busy timeout\n");
error = -ETIMEDOUT;
goto out;
}
- udelay(1000);
} while (status & SUNXI_MMC_STATUS_CARD_DATA_BUSY);
}
if (cmd->resp_type & MMC_RSP_136) {
cmd->response[0] = readl(&mmchost->reg->resp3);
cmd->response[1] = readl(&mmchost->reg->resp2);
cmd->response[2] = readl(&mmchost->reg->resp1);
cmd->response[3] = readl(&mmchost->reg->resp0);
debug("mmc resp 0x%08x 0x%08x 0x%08x 0x%08x\n",
cmd->response[3], cmd->response[2],
cmd->response[1], cmd->response[0]);
} else {
cmd->response[0] = readl(&mmchost->reg->resp0);
debug("mmc resp 0x%08x\n", cmd->response[0]);
}
--
1.9.1
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