uboot-tools/sunxi-improve-throughput-in-the-sunxi_mmc-driver.patch

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4.2 KiB
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From patchwork Wed Mar 21 11:18:58 2018
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Subject: [U-Boot] sunxi: improve throughput in the sunxi_mmc driver
X-Patchwork-Submitter: Maxime Ripard <maxime.ripard@bootlin.com>
X-Patchwork-Id: 888703
X-Patchwork-Delegate: jagannadh.teki@gmail.com
Message-Id: <20180321111858.16576-1-maxime.ripard@bootlin.com>
To: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Mylene Josserand <mylene.josserand@bootlin.com>,
Maxime Ripard <maxime.ripard@bootlin.com>, u-boot@lists.denx.de,
Jagan Teki <jagan@openedev.com>
Date: Wed, 21 Mar 2018 12:18:58 +0100
From: Maxime Ripard <maxime.ripard@bootlin.com>
List-Id: U-Boot discussion <u-boot.lists.denx.de>
From: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
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).
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Tested-by: Mylène Josserand <mylene.josserand@bootlin.com>
---
drivers/mmc/sunxi_mmc.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)
diff --git a/drivers/mmc/sunxi_mmc.c b/drivers/mmc/sunxi_mmc.c
index 4edb4be46c81..d36c1689e7b1 100644
--- a/drivers/mmc/sunxi_mmc.c
+++ b/drivers/mmc/sunxi_mmc.c
@@ -187,15 +187,16 @@ static int mmc_update_clk(struct sunxi_mmc_priv *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, &priv->reg->cmd);
while (readl(&priv->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 */
@@ -276,18 +277,21 @@ static int mmc_trans_data_by_cpu(struct sunxi_mmc_priv *priv, struct mmc *mmc,
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(&priv->reg->gctrl, SUNXI_MMC_GCTRL_ACCESS_BY_AHB);
+ start = get_timer(0);
+
for (i = 0; i < (byte_cnt >> 2); i++) {
while (readl(&priv->reg->status) & status_bit) {
- if (!timeout_usecs--)
+ if (get_timer(start) > timeout_msecs)
return -1;
- udelay(1);
}
if (reading)
@@ -303,16 +307,16 @@ static int mmc_rint_wait(struct sunxi_mmc_priv *priv, struct mmc *mmc,
uint timeout_msecs, uint done_bit, const char *what)
{
unsigned int status;
+ unsigned long start = get_timer(0);
do {
status = readl(&priv->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;
@@ -404,15 +408,16 @@ static int sunxi_mmc_send_cmd_common(struct sunxi_mmc_priv *priv,
}
if (cmd->resp_type & MMC_RSP_BUSY) {
+ unsigned long start = get_timer(0);
timeout_msecs = 2000;
+
do {
status = readl(&priv->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);
}