diff options
| author | Philipp Tomsich <philipp.tomsich@theobroma-systems.com> | 2016-05-18 12:32:05 +0200 |
|---|---|---|
| committer | Klaus Goger <klaus.goger@theobroma-systems.com> | 2016-09-18 15:57:27 +0200 |
| commit | 5a7df64aa96692ffb2043ffdda5200ef1b86fe55 (patch) | |
| tree | 5759f3b04ae66496124ddbcb57fe52cc862c04b6 | |
| parent | 88adcd9e71e07157a516d2befeef4d70abca6586 (diff) | |
sunxi: improve throughput in the sunxi_mmc driver
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 is greater than 10x (e.g. a 10MB write
decreases from 9.302s to 0.884s).
X-Affected-platforms: A31-uQ7, A80-Q7
| -rw-r--r-- | drivers/mmc/sunxi_mmc.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/drivers/mmc/sunxi_mmc.c b/drivers/mmc/sunxi_mmc.c index bf6b22238a..7661d4e41c 100644 --- a/drivers/mmc/sunxi_mmc.c +++ b/drivers/mmc/sunxi_mmc.c @@ -182,15 +182,15 @@ 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 */ @@ -275,17 +275,20 @@ static int mmc_trans_data_by_cpu(struct mmc *mmc, struct mmc_data *data) unsigned *buff = (unsigned int *)(reading ? data->dest : data->src); unsigned byte_cnt = data->blocksize * data->blocks; 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_msecs--) + if (get_timer(start) > timeout_msecs) return -1; - udelay(1000); } if (reading) @@ -302,16 +305,16 @@ static int mmc_rint_wait(struct mmc *mmc, unsigned int timeout_msecs, { 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 TIMEOUT; } - udelay(1000); } while (!(status & done_bit)); return 0; @@ -402,15 +405,16 @@ static int sunxi_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, } 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 = TIMEOUT; goto out; } - udelay(1000); } while (status & SUNXI_MMC_STATUS_CARD_DATA_BUSY); } |