Introduce _mmc_handle_undervoltage() to handle undervoltage events for
MMC/eMMC devices. This function interrupts ongoing operations using HPI
and performs a controlled suspend. After completing the sequence, the card
is marked as removed to prevent further interactions.
To support this, introduce __mmc_suspend() and __mmc_resume() as internal
helpers that omit mmc_claim_host()/mmc_release_host(), allowing them to be
called when the host is already claimed. Update mmc_shutdown() to skip the
normal shutdown sequence if the host is flagged as undervoltage to avoid
repeating of the shutdown procedure.
Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
drivers/mmc/core/mmc.c | 81 +++++++++++++++++++++++++++++++++++-------
1 file changed, 68 insertions(+), 13 deletions(-)
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 86b608843232..e626213e7a52 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -2104,8 +2104,8 @@ static int _mmc_flush_cache(struct mmc_host *host)
return err;
}
-static int _mmc_suspend(struct mmc_host *host, bool is_suspend,
- bool is_undervoltage)
+static int __mmc_suspend(struct mmc_host *host, bool is_suspend,
+ bool is_undervoltage)
{
unsigned int notify_type;
int err = 0;
@@ -2115,8 +2115,6 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend,
else
notify_type = EXT_CSD_POWER_OFF_LONG;
- mmc_claim_host(host);
-
if (mmc_card_suspended(host->card))
goto out;
@@ -2140,7 +2138,18 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend,
mmc_card_set_suspended(host->card);
}
out:
+ return err;
+}
+
+static int _mmc_suspend(struct mmc_host *host, bool is_suspend,
+ bool is_undervoltage)
+{
+ int err;
+
+ mmc_claim_host(host);
+ err = __mmc_suspend(host, is_suspend, is_undervoltage);
mmc_release_host(host);
+
return err;
}
@@ -2160,6 +2169,20 @@ static int mmc_suspend(struct mmc_host *host)
return err;
}
+static int __mmc_resume(struct mmc_host *host)
+{
+ int err;
+
+ if (!mmc_card_suspended(host->card))
+ return 0;
+
+ mmc_power_up(host, host->card->ocr);
+ err = mmc_init_card(host, host->card->ocr, host->card);
+ mmc_card_clr_suspended(host->card);
+
+ return err;
+}
+
/*
* This function tries to determine if the same card is still present
* and, if so, restore all state to it.
@@ -2169,16 +2192,9 @@ static int _mmc_resume(struct mmc_host *host)
int err = 0;
mmc_claim_host(host);
-
- if (!mmc_card_suspended(host->card))
- goto out;
-
- mmc_power_up(host, host->card->ocr);
- err = mmc_init_card(host, host->card->ocr, host->card);
- mmc_card_clr_suspended(host->card);
-
-out:
+ err = __mmc_resume(host);
mmc_release_host(host);
+
return err;
}
@@ -2189,6 +2205,9 @@ static int mmc_shutdown(struct mmc_host *host)
{
int err = 0;
+ if (host->undervoltage)
+ return 0;
+
/*
* In a specific case for poweroff notify, we need to resume the card
* before we can shutdown it properly.
@@ -2280,6 +2299,41 @@ static int _mmc_hw_reset(struct mmc_host *host)
return mmc_init_card(host, card->ocr, card);
}
+static int _mmc_handle_undervoltage(struct mmc_host *host)
+{
+ struct mmc_card *card = host->card;
+ int err = 0;
+
+ mmc_claim_host(host);
+
+ if (!host->card)
+ goto out;
+
+ if (mmc_can_poweroff_notify(host->card) &&
+ !(host->caps2 & MMC_CAP2_FULL_PWR_CYCLE))
+ err = __mmc_resume(host);
+
+ if (!err) {
+ err = mmc_interrupt_hpi(card);
+ if (err)
+ pr_err("%s: Interrupt HPI failed, error %d\n",
+ mmc_hostname(host), err);
+
+ err = __mmc_suspend(host, false, true);
+ }
+
+ if (err)
+ pr_err("%s: Undervoltage emergency stop failed\n",
+ mmc_hostname(host));
+
+ mmc_card_set_removed(host->card);
+
+out:
+ mmc_release_host(host);
+
+ return err;
+}
+
static const struct mmc_bus_ops mmc_ops = {
.remove = mmc_remove,
.detect = mmc_detect,
@@ -2292,6 +2346,7 @@ static const struct mmc_bus_ops mmc_ops = {
.hw_reset = _mmc_hw_reset,
.cache_enabled = _mmc_cache_enabled,
.flush_cache = _mmc_flush_cache,
+ .handle_undervoltage = _mmc_handle_undervoltage,
};
/*
--
2.39.5
