Adding ++Heikki

Thanks
Rajat
-----Original Message-----
From: Khandelwal, Rajat <rajat.khandelwal@intel.com> 
Sent: Thursday, December 30, 2021 1:54 PM
To: mika.westerberg@linux.intel.com
Cc: linux-kernel@vger.kernel.org; platform-driver-x86@vger.kernel.org; Khandelwal, Rajat <rajat.khandelwal@intel.com>; Westerberg, Mika <mika.westerberg@intel.com>
Subject: [PATCH] platform/x86: intel_scu_ipc: Keep polling IPC status if it reads IPC_STATUS_ERR

The current implementation returns -EIO if and when IPC_STATUS_ERR is returned and returns -ETIMEDOUT even if the status is busy.
This patch polls the IPC status even if IPC_STATUS_ERR is returned until timeout expires and returns -EBUSY if the status shows busy.
Observed in multiple scenarios, trying to fetch the status of IPC after it shows ERR sometimes eradicates the ERR status.

Signed-off-by: Rajat-Khandelwal <rajat.khandelwal@intel.com>
---
 drivers/platform/x86/intel_scu_ipc.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/intel_scu_ipc.c b/drivers/platform/x86/intel_scu_ipc.c
index 7cc9089d1e14..1f90acaa7212 100644
--- a/drivers/platform/x86/intel_scu_ipc.c
+++ b/drivers/platform/x86/intel_scu_ipc.c
@@ -233,17 +233,23 @@ static inline u32 ipc_data_readl(struct intel_scu_ipc_dev *scu, u32 offset)  static inline int busy_loop(struct intel_scu_ipc_dev *scu)  {
 	unsigned long end = jiffies + IPC_TIMEOUT;
+	u32 status;
 
 	do {
-		u32 status;
-
 		status = ipc_read_status(scu);
-		if (!(status & IPC_STATUS_BUSY))
-			return (status & IPC_STATUS_ERR) ? -EIO : 0;
+		if (!(status & IPC_STATUS_BUSY)) {
+			if (!(status & IPC_STATUS_ERR))
+				return 0;
+		}
 
 		usleep_range(50, 100);
 	} while (time_before(jiffies, end));
 
+	if (status & IPC_STATUS_BUSY)
+		return -EBUSY;
+	if (status & IPC_STATUS_ERR)
+		return -EIO;
+
 	return -ETIMEDOUT;
 }
 
--
2.17.1

Hi Rajat,

On 12/31/21 16:49, Khandelwal, Rajat wrote:
> Adding ++Heikki
> 
> Thanks
> Rajat

If you want me to apply this, please send this as a proper patch, not as an inline
forward to me, with the platform-driver-x86@vger.kernel.org list in the Cc.

Regards,

Hans


> -----Original Message-----
> From: Khandelwal, Rajat <rajat.khandelwal@intel.com> 
> Sent: Thursday, December 30, 2021 1:54 PM
> To: mika.westerberg@linux.intel.com
> Cc: linux-kernel@vger.kernel.org; platform-driver-x86@vger.kernel.org; Khandelwal, Rajat <rajat.khandelwal@intel.com>; Westerberg, Mika <mika.westerberg@intel.com>
> Subject: [PATCH] platform/x86: intel_scu_ipc: Keep polling IPC status if it reads IPC_STATUS_ERR
> 
> The current implementation returns -EIO if and when IPC_STATUS_ERR is returned and returns -ETIMEDOUT even if the status is busy.
> This patch polls the IPC status even if IPC_STATUS_ERR is returned until timeout expires and returns -EBUSY if the status shows busy.
> Observed in multiple scenarios, trying to fetch the status of IPC after it shows ERR sometimes eradicates the ERR status.
> 
> Signed-off-by: Rajat-Khandelwal <rajat.khandelwal@intel.com>
> ---
>  drivers/platform/x86/intel_scu_ipc.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel_scu_ipc.c b/drivers/platform/x86/intel_scu_ipc.c
> index 7cc9089d1e14..1f90acaa7212 100644
> --- a/drivers/platform/x86/intel_scu_ipc.c
> +++ b/drivers/platform/x86/intel_scu_ipc.c
> @@ -233,17 +233,23 @@ static inline u32 ipc_data_readl(struct intel_scu_ipc_dev *scu, u32 offset)  static inline int busy_loop(struct intel_scu_ipc_dev *scu)  {
>  	unsigned long end = jiffies + IPC_TIMEOUT;
> +	u32 status;
>  
>  	do {
> -		u32 status;
> -
>  		status = ipc_read_status(scu);
> -		if (!(status & IPC_STATUS_BUSY))
> -			return (status & IPC_STATUS_ERR) ? -EIO : 0;
> +		if (!(status & IPC_STATUS_BUSY)) {
> +			if (!(status & IPC_STATUS_ERR))
> +				return 0;
> +		}
>  
>  		usleep_range(50, 100);
>  	} while (time_before(jiffies, end));
>  
> +	if (status & IPC_STATUS_BUSY)
> +		return -EBUSY;
> +	if (status & IPC_STATUS_ERR)
> +		return -EIO;
> +
>  	return -ETIMEDOUT;
>  }
>  
> --
> 2.17.1
>