From 39c9af33129c729be813e302fbe4aecfef48064f Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Fri, 28 Mar 2025 16:35:39 +0000
Subject: [PATCH 1/3] mmc: Speed up reboot with an absent card
On devices with no card detect mechanism, the host ends up polling for
the insertion of a card. This polling happens at multiple frequencies
and with many steps (SDIO, SD, MMC), some of which involve timeouts.
If a reboot is requested during one of those scans, it will stall,
pointlessly, for up to a minute while it completes.
Attempt to short circuit the rescan if the MMC interface is being
removed.
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/mmc/core/core.c | 15 ++++++++++++++-
drivers/mmc/core/mmc_ops.c | 3 +++
drivers/mmc/core/sdio.c | 4 ++++
3 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 95d40fd263698c..bed4d7fe8b9cca 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -399,10 +399,16 @@ void mmc_wait_for_req_done(struct mmc_host *host, struct mmc_request *mrq)
struct mmc_command *cmd;
while (1) {
- wait_for_completion(&mrq->completion);
+ if (!host->rescan_disable)
+ wait_for_completion(&mrq->completion);
cmd = mrq->cmd;
+ if (host->rescan_disable) {
+ cmd->error = -ENOENT;
+ break;
+ }
+
if (!cmd->error || !cmd->retries ||
mmc_card_removed(host->card))
break;
@@ -619,6 +625,11 @@ EXPORT_SYMBOL(mmc_is_req_done);
*/
void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
+ if (host->rescan_disable) {
+ mrq->cmd->error = -ENOENT;
+ return;
+ }
+
__mmc_start_req(host, mrq);
if (!mrq->cap_cmd_during_tfr)
@@ -2265,6 +2276,8 @@ void mmc_rescan(struct work_struct *work)
for (i = 0; i < ARRAY_SIZE(freqs); i++) {
unsigned int freq = freqs[i];
+ if (host->rescan_disable)
+ return;
if (freq > host->f_max) {
if (i + 1 < ARRAY_SIZE(freqs))
continue;
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 3b3adbddf6641e..7db55752a671d9 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -512,6 +512,9 @@ int __mmc_poll_for_busy(struct mmc_host *host, unsigned int period_us,
timeout = jiffies + msecs_to_jiffies(timeout_ms) + 1;
do {
+ if (host->rescan_disable)
+ return -ENOENT;
+
/*
* Due to the possibility of being preempted while polling,
* check the expiration time first.
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 4b19b8a16b0968..0954d43e41365b 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -673,6 +673,10 @@ static int mmc_sdio_init_card(struct mmc_host *host, u32 ocr,
ocr |= R4_18V_PRESENT;
try_again:
+ if (host->rescan_disable) {
+ err = -ENOENT;
+ goto remove;
+ }
if (!retries) {
pr_warn("%s: Skipping voltage switch\n", mmc_hostname(host));
ocr &= ~R4_18V_PRESENT;
From 0c7e4a4d03471d6a316a940fd79ecaa0dc482989 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Mon, 31 Mar 2025 11:24:35 +0100
Subject: [PATCH 2/3] mmc: sdhci: reduce default timeout to 5s
Reduce the maximum time it takes to get to reboot by decreasing the
default SDHCI timeout to 5 seconds.
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/mmc/host/sdhci.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 9bb360efe5b857..80027f0ee8205e 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1629,6 +1629,7 @@ static void sdhci_finish_data(struct sdhci_host *host)
static bool sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
{
+ const unsigned long default_timeout_secs = 5;
int flags;
u32 mask;
unsigned long timeout;
@@ -1704,10 +1705,10 @@ static bool sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
timeout = jiffies;
if (host->data_timeout)
timeout += nsecs_to_jiffies(host->data_timeout);
- else if (!cmd->data && cmd->busy_timeout > 9000)
+ else if (!cmd->data && cmd->busy_timeout > (default_timeout_secs - 1) * 1000)
timeout += DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
else
- timeout += 10 * HZ;
+ timeout += default_timeout_secs * HZ;
sdhci_mod_timer(host, cmd->mrq, timeout);
if (host->use_external_dma)
From a5804e5715411a4533d7ec06283847d6c226f29c Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Mon, 31 Mar 2025 10:16:09 +0100
Subject: [PATCH 3/3] mmc: sdhci: Avoid a NULL pointer crash
Two days into running a reboot test over the weekend, the SDHCI driver
hit a NULL pointer in sdhci_needs_reset. It's not clear how that has
been added by the changes for a faster reboot, but guard against it
explicitly.
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/mmc/host/sdhci.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 80027f0ee8205e..64c44a74cb5966 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1490,6 +1490,8 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host,
static bool sdhci_needs_reset(struct sdhci_host *host, struct mmc_request *mrq)
{
+ if (!mrq)
+ return false;
return (!(host->flags & SDHCI_DEVICE_DEAD) &&
((mrq->cmd && mrq->cmd->error) ||
(mrq->sbc && mrq->sbc->error) ||