[v3] change UIC command handling

[RESEND PATCH v3 2/2] ufs: poll HCS.UCRDY before issuing a UIC command

Posted by Kiwoong Kim 2 years, 6 months ago

With auto hibern8 enabled, UIC could be working
for a while to process a hibern8 operation and HCI
reports UIC not ready for a short term through HCS.UCRDY.
And UFS driver can't recognize the operation.
UFSHCI spec specifies UCRDY like this:
whether the host controller is ready to process UIC COMMAND

The 'ready' could be seen as many different meanings. If the meaning
includes not processing any request from HCI, processing a hibern8
operation can be 'not ready'. In this situation, the driver needs to
wait until the operations is completed.

Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
---
 drivers/ufs/core/ufshcd.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index a89d39a..10ccc85 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -22,6 +22,7 @@
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
 #include <linux/sched/clock.h>
+#include <linux/iopoll.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_dbg.h>
 #include <scsi/scsi_driver.h>
@@ -2365,7 +2366,11 @@ static inline int ufshcd_hba_capabilities(struct ufs_hba *hba)
  */
 static inline bool ufshcd_ready_for_uic_cmd(struct ufs_hba *hba)
 {
-	return ufshcd_readl(hba, REG_CONTROLLER_STATUS) & UIC_COMMAND_READY;
+	u32 val;
+	int ret = read_poll_timeout(ufshcd_readl, val, val & UIC_COMMAND_READY,
+				    500, UIC_CMD_TIMEOUT * 1000, false, hba,
+				    REG_CONTROLLER_STATUS);
+	return ret == 0 ? true : false;
 }
 
 /**
-- 
2.7.4

Re: [RESEND PATCH v3 2/2] ufs: poll HCS.UCRDY before issuing a UIC command

Posted by Adrian Hunter 2 years, 5 months ago

On 2/08/23 04:28, Kiwoong Kim wrote:
> With auto hibern8 enabled, UIC could be working
> for a while to process a hibern8 operation and HCI
> reports UIC not ready for a short term through HCS.UCRDY.
> And UFS driver can't recognize the operation.
> UFSHCI spec specifies UCRDY like this:
> whether the host controller is ready to process UIC COMMAND
> 
> The 'ready' could be seen as many different meanings. If the meaning
> includes not processing any request from HCI, processing a hibern8
> operation can be 'not ready'. In this situation, the driver needs to
> wait until the operations is completed.
> 
> Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> ---
>  drivers/ufs/core/ufshcd.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index a89d39a..10ccc85 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -22,6 +22,7 @@
>  #include <linux/module.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/sched/clock.h>
> +#include <linux/iopoll.h>
>  #include <scsi/scsi_cmnd.h>
>  #include <scsi/scsi_dbg.h>
>  #include <scsi/scsi_driver.h>
> @@ -2365,7 +2366,11 @@ static inline int ufshcd_hba_capabilities(struct ufs_hba *hba)
>   */
>  static inline bool ufshcd_ready_for_uic_cmd(struct ufs_hba *hba)
>  {
> -	return ufshcd_readl(hba, REG_CONTROLLER_STATUS) & UIC_COMMAND_READY;
> +	u32 val;
> +	int ret = read_poll_timeout(ufshcd_readl, val, val & UIC_COMMAND_READY,
> +				    500, UIC_CMD_TIMEOUT * 1000, false, hba,
> +				    REG_CONTROLLER_STATUS);
> +	return ret == 0 ? true : false;

Could use a comment in the code.

And perhaps the following is neater:

	u32 val;

	return !read_poll_timeout(ufshcd_readl, val, val & UIC_COMMAND_READY,
				  500, UIC_CMD_TIMEOUT * 1000, false, hba,
				  REG_CONTROLLER_STATUS);

>  }
>  
>  /**

Re: [RESEND PATCH v3 2/2] ufs: poll HCS.UCRDY before issuing a UIC command

Posted by Bart Van Assche 2 years, 5 months ago

On 8/14/23 04:26, Adrian Hunter wrote:
> And perhaps the following is neater:
> 
> 	u32 val;
> 
> 	return !read_poll_timeout(ufshcd_readl, val, val & UIC_COMMAND_READY,
> 				  500, UIC_CMD_TIMEOUT * 1000, false, hba,
> 				  REG_CONTROLLER_STATUS);

Would the above make readers of that code wonder whether read_poll_timeout()
perhaps returns a boolean? Wouldn't it be better to test the
read_poll_timeout() return value as follows?

  	return read_poll_timeout(ufshcd_readl, val, val & UIC_COMMAND_READY,
  				  500, UIC_CMD_TIMEOUT * 1000, false, hba,
  				  REG_CONTROLLER_STATUS) == 0;

Thanks,

Bart.

Re: [RESEND PATCH v3 2/2] ufs: poll HCS.UCRDY before issuing a UIC command

Posted by Adrian Hunter 2 years, 5 months ago

On 17/08/23 18:02, Bart Van Assche wrote:
> On 8/14/23 04:26, Adrian Hunter wrote:
>> And perhaps the following is neater:
>>
>>     u32 val;
>>
>>     return !read_poll_timeout(ufshcd_readl, val, val & UIC_COMMAND_READY,
>>                   500, UIC_CMD_TIMEOUT * 1000, false, hba,
>>                   REG_CONTROLLER_STATUS);
> 
> Would the above make readers of that code wonder whether read_poll_timeout()
> perhaps returns a boolean? Wouldn't it be better to test the
> read_poll_timeout() return value as follows?
> 
>      return read_poll_timeout(ufshcd_readl, val, val & UIC_COMMAND_READY,
>                    500, UIC_CMD_TIMEOUT * 1000, false, hba,
>                    REG_CONTROLLER_STATUS) == 0;
> 

Either is fine, otherwise:

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>