[RFC PATCH] mmc: cqhci: keep CQE enabled if halt times out

[RFC PATCH] mmc: cqhci: keep CQE enabled if halt times out

[Pengpeng Hou]

cqhci_off() asks the controller to halt before post_disable(), clearing
mmc->cqe_on and freeing CQE resources. If the halt wait times out, the
function still continues through that success path even though the
hardware may still be using the command queue.

Make cqhci_off() report whether the halt completed and leave the CQE
state/resources intact when the controller remains stuck on. This keeps
the existing host-specific ->disable() ordering and is intended as an
RFC patch because the cqe_disable callback itself has no error return.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
---
 drivers/mmc/host/cqhci-core.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
index 178277d90..84846207c 100644
--- a/drivers/mmc/host/cqhci-core.c
+++ b/drivers/mmc/host/cqhci-core.c
@@ -372,14 +372,14 @@ static u32 cqhci_read_ctl(struct cqhci_host *cq_host)
 	return cqhci_readl(cq_host, CQHCI_CTL);
 }
 
-static void cqhci_off(struct mmc_host *mmc)
+static bool cqhci_off(struct mmc_host *mmc)
 {
 	struct cqhci_host *cq_host = mmc->cqe_private;
 	u32 reg;
 	int err;
 
 	if (!cq_host->enabled || !mmc->cqe_on || cq_host->recovery_halt)
-		return;
+		return true;
 
 	if (cq_host->ops->disable)
 		cq_host->ops->disable(mmc, false);
@@ -388,15 +388,19 @@ static void cqhci_off(struct mmc_host *mmc)
 
 	err = readx_poll_timeout(cqhci_read_ctl, cq_host, reg,
 				 reg & CQHCI_HALT, 0, CQHCI_OFF_TIMEOUT);
-	if (err < 0)
+	if (err < 0) {
 		pr_err("%s: cqhci: CQE stuck on\n", mmc_hostname(mmc));
-	else
-		pr_debug("%s: cqhci: CQE off\n", mmc_hostname(mmc));
+		return false;
+	}
+
+	pr_debug("%s: cqhci: CQE off\n", mmc_hostname(mmc));
 
 	if (cq_host->ops->post_disable)
 		cq_host->ops->post_disable(mmc);
 
 	mmc->cqe_on = false;
+
+	return true;
 }
 
 static void cqhci_disable(struct mmc_host *mmc)
@@ -406,7 +410,8 @@ static void cqhci_disable(struct mmc_host *mmc)
 	if (!cq_host->enabled)
 		return;
 
-	cqhci_off(mmc);
+	if (!cqhci_off(mmc))
+		return;
 
 	__cqhci_disable(cq_host);
 
-- 
2.50.1 (Apple Git-155)

Re: [RFC PATCH] mmc: cqhci: keep CQE enabled if halt times out

[Adrian Hunter]

On 23/06/2026 17:04, Pengpeng Hou wrote:
> cqhci_off() asks the controller to halt before post_disable(), clearing
> mmc->cqe_on and freeing CQE resources. If the halt wait times out, the
> function still continues through that success path even though the
> hardware may still be using the command queue.

CQHCI should be idle when cqhci_off() is used, so it should halt
immediately.  If not, it is a hardware error, but carrying on is
a reasonable option because I/O errors will trigger recovery
later.

> 
> Make cqhci_off() report whether the halt completed and leave the CQE
> state/resources intact when the controller remains stuck on. This keeps
> the existing host-specific ->disable() ordering and is intended as an
> RFC patch because the cqe_disable callback itself has no error return.

Is there a real problem that you are trying to fix?

> 
> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
> ---
>  drivers/mmc/host/cqhci-core.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mmc/host/cqhci-core.c b/drivers/mmc/host/cqhci-core.c
> index 178277d90..84846207c 100644
> --- a/drivers/mmc/host/cqhci-core.c
> +++ b/drivers/mmc/host/cqhci-core.c
> @@ -372,14 +372,14 @@ static u32 cqhci_read_ctl(struct cqhci_host *cq_host)
>  	return cqhci_readl(cq_host, CQHCI_CTL);
>  }
>  
> -static void cqhci_off(struct mmc_host *mmc)
> +static bool cqhci_off(struct mmc_host *mmc)
>  {
>  	struct cqhci_host *cq_host = mmc->cqe_private;
>  	u32 reg;
>  	int err;
>  
>  	if (!cq_host->enabled || !mmc->cqe_on || cq_host->recovery_halt)
> -		return;
> +		return true;
>  
>  	if (cq_host->ops->disable)
>  		cq_host->ops->disable(mmc, false);
> @@ -388,15 +388,19 @@ static void cqhci_off(struct mmc_host *mmc)
>  
>  	err = readx_poll_timeout(cqhci_read_ctl, cq_host, reg,
>  				 reg & CQHCI_HALT, 0, CQHCI_OFF_TIMEOUT);
> -	if (err < 0)
> +	if (err < 0) {
>  		pr_err("%s: cqhci: CQE stuck on\n", mmc_hostname(mmc));
> -	else
> -		pr_debug("%s: cqhci: CQE off\n", mmc_hostname(mmc));
> +		return false;
> +	}
> +
> +	pr_debug("%s: cqhci: CQE off\n", mmc_hostname(mmc));
>  
>  	if (cq_host->ops->post_disable)
>  		cq_host->ops->post_disable(mmc);
>  
>  	mmc->cqe_on = false;
> +
> +	return true;
>  }
>  
>  static void cqhci_disable(struct mmc_host *mmc)
> @@ -406,7 +410,8 @@ static void cqhci_disable(struct mmc_host *mmc)
>  	if (!cq_host->enabled)
>  		return;
>  
> -	cqhci_off(mmc);
> +	if (!cqhci_off(mmc))
> +		return;
>  
>  	__cqhci_disable(cq_host);
>