[U-Boot] [PATCH v1] sunxi: improve throughput in the sunxi_mmc driver
Chen-Yu Tsai
wens at csie.org
Mon Feb 20 06:16:11 UTC 2017
On Mon, Feb 20, 2017 at 6:08 AM, Jaehoon Chung <jh80.chung at samsung.com> wrote:
> Hi,
>
> On 02/18/2017 02:22 AM, Philipp Tomsich wrote:
>> 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).
>
> Your patch's format looks strange.
> Some unchanging codes are included in patches.
> Except them, Looks good to me.
> If you will resend the patch, you can resend with my acked-by tag.
They were probably produced the patches with "git format-patch
--function-context", which includes the whole body of any changed
functions.
I suppose git would ignore all the extra code when applying the patch,
but it probably increases the likelihood of conflicts.
ChenYu
>
> Best Regards,
> Jaehoon Chung
>
>>
>> X-Affected-platforms: A31-uQ7, A80-Q7, A64-uQ7
>> Signed-off-by: Philipp Tomsich <philipp.tomsich at 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]);
>> }
>>
>
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