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mmc: core: adjust polling interval for CMD1 

In mmc_send_op_cond(), loops are continuously performed at the same
interval of 10 ms.  However the behaviour is not good for some eMMC
which can be out from a busy state earlier than 10 ms if normal.

Rather than fixing about the interval time in mmc_send_op_cond(),
let's instead convert into using the common __mmc_poll_for_busy().

The reason for adjusting the interval time is that it is important
to reduce the eMMC initialization time, especially in devices that
use eMMC as rootfs.

Test log(eMMC:KLM8G1GETF-B041):

before: 12 ms (0.311016 - 0.298729)
[    0.295823] mmc0: starting CMD0 arg 00000000 flags 000000c0
[    0.298729] mmc0: starting CMD1 arg 40000080 flags 000000e1<-start
[    0.311016] mmc0: starting CMD1 arg 40000080 flags 000000e1<-finish
[    0.311336] mmc0: starting CMD2 arg 00000000 flags 00000007

after: 2 ms (0.301270 - 0.298762)
[    0.295862] mmc0: starting CMD0 arg 00000000 flags 000000c0
[    0.298762] mmc0: starting CMD1 arg 40000080 flags 000000e1<-start
[    0.299067] mmc0: starting CMD1 arg 40000080 flags 000000e1
[    0.299441] mmc0: starting CMD1 arg 40000080 flags 000000e1
[    0.299879] mmc0: starting CMD1 arg 40000080 flags 000000e1
[    0.300446] mmc0: starting CMD1 arg 40000080 flags 000000e1
[    0.301270] mmc0: starting CMD1 arg 40000080 flags 000000e1<-finish
[    0.301572] mmc0: starting CMD2 arg 00000000 flags 00000007

Signed-off-by: Huijin Park <huijin.park@samsung.com>
Link: https://lore.kernel.org/r/20211104063231.2115-3-huijin.park@samsung.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Huijin Park 2021-11-04 15:32:31 +09:00 committed by Ulf Hansson
parent 2ebbdace5c
commit 76bfc7ccc2
1 changed files with 54 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

83
drivers/mmc/core/mmc_ops.c
View File

@ -58,6 +58,12 @@ struct mmc_busy_data {
enum mmc_busy_cmd busy_cmd;
};
struct mmc_op_cond_busy_data {
struct mmc_host *host;
u32 ocr;
struct mmc_command *cmd;
};
int __mmc_send_status(struct mmc_card *card, u32 *status, unsigned int retries)
{
int err;
@ -173,43 +179,62 @@ int mmc_go_idle(struct mmc_host *host)
return err;
}
static int __mmc_send_op_cond_cb(void *cb_data, bool *busy)
{
struct mmc_op_cond_busy_data *data = cb_data;
struct mmc_host *host = data->host;
struct mmc_command *cmd = data->cmd;
u32 ocr = data->ocr;
int err = 0;
err = mmc_wait_for_cmd(host, cmd, 0);
if (err)
return err;
if (mmc_host_is_spi(host)) {
if (!(cmd->resp[0] & R1_SPI_IDLE)) {
*busy = false;
return 0;
}
} else {
if (cmd->resp[0] & MMC_CARD_BUSY) {
*busy = false;
return 0;
}
}
*busy = true;
/*
* According to eMMC specification v5.1 section 6.4.3, we
* should issue CMD1 repeatedly in the idle state until
* the eMMC is ready. Otherwise some eMMC devices seem to enter
* the inactive mode after mmc_init_card() issued CMD0 when
* the eMMC device is busy.
*/
if (!ocr && !mmc_host_is_spi(host))
cmd->arg = cmd->resp[0] | BIT(30);
return 0;
}
int mmc_send_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr)
{
struct mmc_command cmd = {};
int i, err = 0;
int err = 0;
struct mmc_op_cond_busy_data cb_data = {
.host = host,
.ocr = ocr,
.cmd = &cmd
};
cmd.opcode = MMC_SEND_OP_COND;
cmd.arg = mmc_host_is_spi(host) ? 0 : ocr;
cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R3 | MMC_CMD_BCR;
for (i = 100; i; i--) {
err = mmc_wait_for_cmd(host, &cmd, 0);
if (err)
break;
/* wait until reset completes */
if (mmc_host_is_spi(host)) {
if (!(cmd.resp[0] & R1_SPI_IDLE))
break;
} else {
if (cmd.resp[0] & MMC_CARD_BUSY)
break;
}
err = -ETIMEDOUT;
mmc_delay(10);
/*
* According to eMMC specification v5.1 section 6.4.3, we
* should issue CMD1 repeatedly in the idle state until
* the eMMC is ready. Otherwise some eMMC devices seem to enter
* the inactive mode after mmc_init_card() issued CMD0 when
* the eMMC device is busy.
*/
if (!ocr && !mmc_host_is_spi(host))
cmd.arg = cmd.resp[0] | BIT(30);
}
err = __mmc_poll_for_busy(host, 1000, &__mmc_send_op_cond_cb, &cb_data);
if (err)
return err;
if (rocr && !mmc_host_is_spi(host))
*rocr = cmd.resp[0];