If the host controller supports busy detection in HW, we expect the
MMC_CAP_WAIT_WHILE_BUSY to be set. Likewise the corresponding
host->max_busy_timeout shall reflect the maximum busy detection timeout
supported by the host. A timeout set to zero, is interpreted as the
host supports whatever timeout the mmc core provides it with.
Previously we expected a host that supported MMC_CAP_WAIT_WHILE_BUSY to
cope with any timeout, which just isn't feasible due to HW limitations.
For most switch operations, R1B responses are expected and thus we need
to check for busy detection completion. To cope with cases where the
requested busy detection timeout is greater than what the host are able
to support, we fallback to use a R1 response instead. This will prevent
the host from doing HW busy detection.
In those cases busy detection completion is handled by polling the for
the card's status using CMD13, which is the same mechanism used when
the host doesn't support MMC_CAP_WAIT_WHILE_BUSY.
Signed-off-by: Ulf Hansson <ulf.hans...@linaro.org>
---
drivers/mmc/core/mmc_ops.c | 53 ++++++++++++++++++++++++++++++--------------
1 file changed, 36 insertions(+), 17 deletions(-)
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 5e1a2cb..2e0cccb 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -413,13 +413,31 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index,
u8 value,
unsigned int timeout_ms, bool use_busy_signal, bool send_status,
bool ignore_crc)
{
+ struct mmc_host *host;
int err;
struct mmc_command cmd = {0};
unsigned long timeout;
+ unsigned int max_busy_timeout;
u32 status = 0;
+ bool use_r1b_resp = true;
BUG_ON(!card);
BUG_ON(!card->host);
+ host = card->host;
+
+ /* Once all callers provides a timeout, remove this fallback. */
+ if (!timeout_ms)
+ timeout_ms = MMC_OPS_TIMEOUT_MS;
+
+ /* We interpret unspecified timeouts as the host can cope with all. */
+ max_busy_timeout = host->max_busy_timeout ?
+ host->max_busy_timeout : timeout_ms;
+
+ if (use_busy_signal && (host->caps & MMC_CAP_WAIT_WHILE_BUSY) &&
+ (timeout_ms > max_busy_timeout))
+ use_r1b_resp = false;
+ else if (!use_busy_signal)
+ use_r1b_resp = false;
cmd.opcode = MMC_SWITCH;
cmd.arg = (MMC_SWITCH_MODE_WRITE_BYTE << 24) |
@@ -427,17 +445,25 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index,
u8 value,
(value << 8) |
set;
cmd.flags = MMC_CMD_AC;
- if (use_busy_signal)
+ if (use_r1b_resp)
cmd.flags |= MMC_RSP_SPI_R1B | MMC_RSP_R1B;
else
cmd.flags |= MMC_RSP_SPI_R1 | MMC_RSP_R1;
+ if ((host->caps & MMC_CAP_WAIT_WHILE_BUSY) && use_r1b_resp) {
+ /* Tell the host what busy detection timeout to use. */
+ cmd.busy_timeout = timeout_ms;
+ /*
+ * CRC errors shall only be ignored in cases were CMD13 is used
+ * to poll to detect busy completion.
+ */
+ ignore_crc = false;
+ }
- cmd.busy_timeout = timeout_ms;
if (index == EXT_CSD_SANITIZE_START)
cmd.sanitize_busy = true;
- err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES);
+ err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);
if (err)
return err;
@@ -445,24 +471,17 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index,
u8 value,
if (!use_busy_signal)
return 0;
- /*
- * CRC errors shall only be ignored in cases were CMD13 is used to poll
- * to detect busy completion.
- */
- if (card->host->caps & MMC_CAP_WAIT_WHILE_BUSY)
- ignore_crc = false;
-
/* Must check status to be sure of no errors. */
- timeout = jiffies + msecs_to_jiffies(MMC_OPS_TIMEOUT_MS);
+ timeout = jiffies + msecs_to_jiffies(timeout_ms);
do {
if (send_status) {
err = __mmc_send_status(card, &status, ignore_crc);
if (err)
return err;
}
- if (card->host->caps & MMC_CAP_WAIT_WHILE_BUSY)
+ if ((host->caps & MMC_CAP_WAIT_WHILE_BUSY) && use_r1b_resp)
break;
- if (mmc_host_is_spi(card->host))
+ if (mmc_host_is_spi(host))
break;
/*
@@ -478,18 +497,18 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index,
u8 value,
/* Timeout if the device never leaves the program state. */
if (time_after(jiffies, timeout)) {
pr_err("%s: Card stuck in programming state! %s\n",
- mmc_hostname(card->host), __func__);
+ mmc_hostname(host), __func__);
return -ETIMEDOUT;
}
} while (R1_CURRENT_STATE(status) == R1_STATE_PRG);
- if (mmc_host_is_spi(card->host)) {
+ if (mmc_host_is_spi(host)) {
if (status & R1_SPI_ILLEGAL_COMMAND)
return -EBADMSG;
} else {
if (status & 0xFDFFA000)
- pr_warning("%s: unexpected status %#x after "
- "switch", mmc_hostname(card->host), status);
+ pr_warn("%s: unexpected status %#x after switch\n",
+ mmc_hostname(host), status);
if (status & R1_SWITCH_ERROR)
return -EBADMSG;
}
--
1.7.9.5
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