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Subject[PATCH] mmc: mmc: do not use CMD13 to get status after speed mode switch
Date
Per JEDEC spec, it is not recommended to use CMD13 to get card status
after speed mode switch. below are two reason about this:
1. CMD13 cannot be guaranteed due to the asynchronous operation.
Therefore it is not recommended to use CMD13 to check busy completion
of the timing change indication.
2. After switch to HS200, CMD13 will get response of 0x800, and even the
busy signal gets de-asserted, the response of CMD13 is aslo 0x800.

this patch drops CMD13 when doing speed mode switch, if host do not
support MMC_CAP_WAIT_WHILE_BUSY and there is no ops->card_busy(),
then the only way is to wait a fixed timeout.

Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
---
drivers/mmc/core/mmc.c | 82 ++++++++++++++++----------------------------
drivers/mmc/core/mmc_ops.c | 25 +++++++++-----
2 files changed, 45 insertions(+), 62 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 4dbe3df..03ee7a4 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -962,7 +962,7 @@ static int mmc_select_hs(struct mmc_card *card)
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_HS_TIMING, EXT_CSD_TIMING_HS,
card->ext_csd.generic_cmd6_time,
- true, true, true);
+ true, false, true);
if (!err)
mmc_set_timing(card->host, MMC_TIMING_MMC_HS);

@@ -1056,7 +1056,6 @@ static int mmc_switch_status(struct mmc_card *card)
static int mmc_select_hs400(struct mmc_card *card)
{
struct mmc_host *host = card->host;
- bool send_status = true;
unsigned int max_dtr;
int err = 0;
u8 val;
@@ -1068,9 +1067,6 @@ static int mmc_select_hs400(struct mmc_card *card)
host->ios.bus_width == MMC_BUS_WIDTH_8))
return 0;

- if (host->caps & MMC_CAP_WAIT_WHILE_BUSY)
- send_status = false;
-
/* Reduce frequency to HS frequency */
max_dtr = card->ext_csd.hs_max_dtr;
mmc_set_clock(host, max_dtr);
@@ -1080,7 +1076,7 @@ static int mmc_select_hs400(struct mmc_card *card)
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_HS_TIMING, val,
card->ext_csd.generic_cmd6_time,
- true, send_status, true);
+ true, false, true);
if (err) {
pr_err("%s: switch to high-speed from hs200 failed, err:%d\n",
mmc_hostname(host), err);
@@ -1090,11 +1086,9 @@ static int mmc_select_hs400(struct mmc_card *card)
/* Set host controller to HS timing */
mmc_set_timing(card->host, MMC_TIMING_MMC_HS);

- if (!send_status) {
- err = mmc_switch_status(card);
- if (err)
- goto out_err;
- }
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;

/* Switch card to DDR */
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
@@ -1113,7 +1107,7 @@ static int mmc_select_hs400(struct mmc_card *card)
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_HS_TIMING, val,
card->ext_csd.generic_cmd6_time,
- true, send_status, true);
+ true, false, true);
if (err) {
pr_err("%s: switch to hs400 failed, err:%d\n",
mmc_hostname(host), err);
@@ -1124,11 +1118,9 @@ static int mmc_select_hs400(struct mmc_card *card)
mmc_set_timing(host, MMC_TIMING_MMC_HS400);
mmc_set_bus_speed(card);

- if (!send_status) {
- err = mmc_switch_status(card);
- if (err)
- goto out_err;
- }
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;

return 0;

@@ -1146,14 +1138,10 @@ int mmc_hs200_to_hs400(struct mmc_card *card)
int mmc_hs400_to_hs200(struct mmc_card *card)
{
struct mmc_host *host = card->host;
- bool send_status = true;
unsigned int max_dtr;
int err;
u8 val;

- if (host->caps & MMC_CAP_WAIT_WHILE_BUSY)
- send_status = false;
-
/* Reduce frequency to HS */
max_dtr = card->ext_csd.hs_max_dtr;
mmc_set_clock(host, max_dtr);
@@ -1162,49 +1150,43 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
val = EXT_CSD_TIMING_HS;
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
val, card->ext_csd.generic_cmd6_time,
- true, send_status, true);
+ true, false, true);
if (err)
goto out_err;

mmc_set_timing(host, MMC_TIMING_MMC_DDR52);

- if (!send_status) {
- err = mmc_switch_status(card);
- if (err)
- goto out_err;
- }
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;

/* Switch HS DDR to HS */
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_BUS_WIDTH,
EXT_CSD_BUS_WIDTH_8, card->ext_csd.generic_cmd6_time,
- true, send_status, true);
+ true, false, true);
if (err)
goto out_err;

mmc_set_timing(host, MMC_TIMING_MMC_HS);

- if (!send_status) {
- err = mmc_switch_status(card);
- if (err)
- goto out_err;
- }
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;

/* Switch HS to HS200 */
val = EXT_CSD_TIMING_HS200 |
card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
val, card->ext_csd.generic_cmd6_time, true,
- send_status, true);
+ false, true);
if (err)
goto out_err;

mmc_set_timing(host, MMC_TIMING_MMC_HS200);

- if (!send_status) {
- err = mmc_switch_status(card);
- if (err)
- goto out_err;
- }
+ err = mmc_switch_status(card);
+ if (err)
+ goto out_err;

mmc_set_bus_speed(card);

@@ -1243,7 +1225,6 @@ static void mmc_select_driver_type(struct mmc_card *card)
static int mmc_select_hs200(struct mmc_card *card)
{
struct mmc_host *host = card->host;
- bool send_status = true;
unsigned int old_timing;
int err = -EINVAL;
u8 val;
@@ -1260,9 +1241,6 @@ static int mmc_select_hs200(struct mmc_card *card)

mmc_select_driver_type(card);

- if (host->caps & MMC_CAP_WAIT_WHILE_BUSY)
- send_status = false;
-
/*
* Set the bus width(4 or 8) with host's support and
* switch to HS200 mode if bus width is set successfully.
@@ -1274,20 +1252,18 @@ static int mmc_select_hs200(struct mmc_card *card)
err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_HS_TIMING, val,
card->ext_csd.generic_cmd6_time,
- true, send_status, true);
+ true, false, true);
if (err)
goto err;
old_timing = host->ios.timing;
mmc_set_timing(host, MMC_TIMING_MMC_HS200);
- if (!send_status) {
- err = mmc_switch_status(card);
- /*
- * mmc_select_timing() assumes timing has not changed if
- * it is a switch error.
- */
- if (err == -EBADMSG)
- mmc_set_timing(host, old_timing);
- }
+ err = mmc_switch_status(card);
+ /*
+ * mmc_select_timing() assumes timing has not changed if
+ * it is a switch error.
+ */
+ if (err == -EBADMSG)
+ mmc_set_timing(host, old_timing);
}
err:
if (err)
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 62355bd..32de144 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -480,6 +480,7 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
u32 status = 0;
bool use_r1b_resp = use_busy_signal;
bool expired = false;
+ bool busy = false;

mmc_retune_hold(host);

@@ -535,19 +536,24 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
/* Must check status to be sure of no errors. */
timeout = jiffies + msecs_to_jiffies(timeout_ms);
do {
+ /*
+ * Due to the possibility of being preempted after
+ * sending the status command, check the expiration
+ * time first.
+ */
+ expired = time_after(jiffies, timeout);
if (send_status) {
- /*
- * Due to the possibility of being preempted after
- * sending the status command, check the expiration
- * time first.
- */
- expired = time_after(jiffies, timeout);
err = __mmc_send_status(card, &status, ignore_crc);
if (err)
goto out;
}
if ((host->caps & MMC_CAP_WAIT_WHILE_BUSY) && use_r1b_resp)
break;
+ if (host->ops->card_busy) {
+ if (!host->ops->card_busy(host))
+ break;
+ busy = true;
+ }
if (mmc_host_is_spi(host))
break;

@@ -556,19 +562,20 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
* does'nt support MMC_CAP_WAIT_WHILE_BUSY, then we can only
* rely on waiting for the stated timeout to be sufficient.
*/
- if (!send_status) {
+ if (!send_status && !host->ops->card_busy) {
mmc_delay(timeout_ms);
goto out;
}

/* Timeout if the device never leaves the program state. */
- if (expired && R1_CURRENT_STATE(status) == R1_STATE_PRG) {
+ if (expired &&
+ (R1_CURRENT_STATE(status) == R1_STATE_PRG || busy)) {
pr_err("%s: Card stuck in programming state! %s\n",
mmc_hostname(host), __func__);
err = -ETIMEDOUT;
goto out;
}
- } while (R1_CURRENT_STATE(status) == R1_STATE_PRG);
+ } while (R1_CURRENT_STATE(status) == R1_STATE_PRG || busy);

err = mmc_switch_status_error(host, status);
out:
--
1.7.9.5
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