mmc: core: Do regular power cycle when lacking eMMC HW reset support
The eMMC HW reset may be implemented either via the host ops ->hw_reset()
callback or through DT and the eMMC pwrseq. Additionally some eMMC cards
don't support HW reset.
To allow a reset to be done for the different combinations of mmc hosts
and eMMC/MMC cards, let's implement a fallback via trying a regular power
cycle. This improves the mmc block layer retry mechanism of failing I/O
requests.
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
[Ulf: Rewrote changelog]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index f80b3ab..99275e4 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2456,8 +2456,9 @@
ret = host->bus_ops->reset(host);
mmc_bus_put(host);
- if (ret != -EOPNOTSUPP)
- pr_warn("%s: tried to reset card\n", mmc_hostname(host));
+ if (ret)
+ pr_warn("%s: tried to reset card, got error %d\n",
+ mmc_hostname(host), ret);
return ret;
}
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 4dbe3df..b8aa12c 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1957,19 +1957,17 @@
{
struct mmc_card *card = host->card;
- if (!(host->caps & MMC_CAP_HW_RESET) || !host->ops->hw_reset)
- return -EOPNOTSUPP;
-
- if (!mmc_can_reset(card))
- return -EOPNOTSUPP;
-
- mmc_set_clock(host, host->f_init);
-
- host->ops->hw_reset(host);
-
- /* Set initial state and call mmc_set_ios */
- mmc_set_initial_state(host);
-
+ if ((host->caps & MMC_CAP_HW_RESET) && host->ops->hw_reset &&
+ mmc_can_reset(card)) {
+ /* If the card accept RST_n signal, send it. */
+ mmc_set_clock(host, host->f_init);
+ host->ops->hw_reset(host);
+ /* Set initial state and call mmc_set_ios */
+ mmc_set_initial_state(host);
+ } else {
+ /* Do a brute force power cycle */
+ mmc_power_cycle(host, card->ocr);
+ }
return mmc_init_card(host, card->ocr, card);
}