[PATCH v3 1/1] scsi: ufs: make UFS Tx lane1 clock optional for QCOM platforms

[PATCH v3 1/1] scsi: ufs: make UFS Tx lane1 clock optional for QCOM platforms

[Can Guo]

From: Venkat Gopalakrishnan <venkatg@codeaurora.org>

Per Qcom's UFS host controller HW design, the UFS Tx lane1 clock could be
muxed with Tx lane0 clock, hence keep Tx lane1 clock optional by ignoring
it if it is not provided in device tree. This change also performs some
cleanup to lanes per direction checks when enable/disable lane clocks just
for symmetry.

Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
Changes since v2:
- Incorporated review comments from Doug.

Changes since v1:
- Incorporated review comments from Doug.
- Update the commit title and commit message.

 drivers/scsi/ufs/ufs-qcom.c | 55 ++++++++++++++++++++++++---------------------
 1 file changed, 29 insertions(+), 26 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index 2b38db2..dbc84cb 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -79,20 +79,28 @@ static int ufs_qcom_get_connected_tx_lanes(struct ufs_hba *hba, u32 *tx_lanes)
 }
 
 static int ufs_qcom_host_clk_get(struct device *dev,
-		const char *name, struct clk **clk_out)
+		const char *name, struct clk **clk_out, bool optional)
 {
 	struct clk *clk;
 	int err = 0;
 
 	clk = devm_clk_get(dev, name);
-	if (IS_ERR(clk)) {
-		err = PTR_ERR(clk);
-		dev_err(dev, "%s: failed to get %s err %d",
-				__func__, name, err);
-	} else {
+	if (!IS_ERR(clk)) {
 		*clk_out = clk;
+		return 0;
 	}
 
+	err = PTR_ERR(clk);
+
+	if (optional && err == -ENOENT) {
+		*clk_out = NULL;
+		return 0;
+	}
+
+	if (err != -EPROBE_DEFER)
+		dev_err(dev, "failed to get %s err %d",
+				name, err);
+
 	return err;
 }
 
@@ -113,11 +121,9 @@ static void ufs_qcom_disable_lane_clks(struct ufs_qcom_host *host)
 	if (!host->is_lane_clks_enabled)
 		return;
 
-	if (host->hba->lanes_per_direction > 1)
-		clk_disable_unprepare(host->tx_l1_sync_clk);
+	clk_disable_unprepare(host->tx_l1_sync_clk);
 	clk_disable_unprepare(host->tx_l0_sync_clk);
-	if (host->hba->lanes_per_direction > 1)
-		clk_disable_unprepare(host->rx_l1_sync_clk);
+	clk_disable_unprepare(host->rx_l1_sync_clk);
 	clk_disable_unprepare(host->rx_l0_sync_clk);
 
 	host->is_lane_clks_enabled = false;
@@ -141,24 +147,21 @@ static int ufs_qcom_enable_lane_clks(struct ufs_qcom_host *host)
 	if (err)
 		goto disable_rx_l0;
 
-	if (host->hba->lanes_per_direction > 1) {
-		err = ufs_qcom_host_clk_enable(dev, "rx_lane1_sync_clk",
+	err = ufs_qcom_host_clk_enable(dev, "rx_lane1_sync_clk",
 			host->rx_l1_sync_clk);
-		if (err)
-			goto disable_tx_l0;
+	if (err)
+		goto disable_tx_l0;
 
-		err = ufs_qcom_host_clk_enable(dev, "tx_lane1_sync_clk",
+	err = ufs_qcom_host_clk_enable(dev, "tx_lane1_sync_clk",
 			host->tx_l1_sync_clk);
-		if (err)
-			goto disable_rx_l1;
-	}
+	if (err)
+		goto disable_rx_l1;
 
 	host->is_lane_clks_enabled = true;
 	goto out;
 
 disable_rx_l1:
-	if (host->hba->lanes_per_direction > 1)
-		clk_disable_unprepare(host->rx_l1_sync_clk);
+	clk_disable_unprepare(host->rx_l1_sync_clk);
 disable_tx_l0:
 	clk_disable_unprepare(host->tx_l0_sync_clk);
 disable_rx_l0:
@@ -172,25 +175,25 @@ static int ufs_qcom_init_lane_clks(struct ufs_qcom_host *host)
 	int err = 0;
 	struct device *dev = host->hba->dev;
 
-	err = ufs_qcom_host_clk_get(dev,
-			"rx_lane0_sync_clk", &host->rx_l0_sync_clk);
+	err = ufs_qcom_host_clk_get(dev, "rx_lane0_sync_clk",
+					&host->rx_l0_sync_clk, false);
 	if (err)
 		goto out;
 
-	err = ufs_qcom_host_clk_get(dev,
-			"tx_lane0_sync_clk", &host->tx_l0_sync_clk);
+	err = ufs_qcom_host_clk_get(dev, "tx_lane0_sync_clk",
+					&host->tx_l0_sync_clk, false);
 	if (err)
 		goto out;
 
 	/* In case of single lane per direction, don't read lane1 clocks */
 	if (host->hba->lanes_per_direction > 1) {
 		err = ufs_qcom_host_clk_get(dev, "rx_lane1_sync_clk",
-			&host->rx_l1_sync_clk);
+			&host->rx_l1_sync_clk, false);
 		if (err)
 			goto out;
 
 		err = ufs_qcom_host_clk_get(dev, "tx_lane1_sync_clk",
-			&host->tx_l1_sync_clk);
+			&host->tx_l1_sync_clk, true);
 	}
 out:
 	return err;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v3 1/1] scsi: ufs: make UFS Tx lane1 clock optional for QCOM platforms

[Vivek Gautam]

On 10/12/2018 6:42 AM, Can Guo wrote:
> From: Venkat Gopalakrishnan <venkatg@codeaurora.org>
>
> Per Qcom's UFS host controller HW design, the UFS Tx lane1 clock could be
> muxed with Tx lane0 clock, hence keep Tx lane1 clock optional by ignoring
> it if it is not provided in device tree. This change also performs some
> cleanup to lanes per direction checks when enable/disable lane clocks just
> for symmetry.
>
> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
> Signed-off-by: Can Guo <cang@codeaurora.org>
> ---
> Changes since v2:
> - Incorporated review comments from Doug.
>
> Changes since v1:
> - Incorporated review comments from Doug.
> - Update the commit title and commit message.
>
>   drivers/scsi/ufs/ufs-qcom.c | 55 ++++++++++++++++++++++++---------------------
>   1 file changed, 29 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
> index 2b38db2..dbc84cb 100644
> --- a/drivers/scsi/ufs/ufs-qcom.c
> +++ b/drivers/scsi/ufs/ufs-qcom.c
> @@ -79,20 +79,28 @@ static int ufs_qcom_get_connected_tx_lanes(struct ufs_hba *hba, u32 *tx_lanes)
>   }
>   
>   static int ufs_qcom_host_clk_get(struct device *dev,
> -		const char *name, struct clk **clk_out)
> +		const char *name, struct clk **clk_out, bool optional)
>   {
>   	struct clk *clk;
>   	int err = 0;
>   
>   	clk = devm_clk_get(dev, name);
> -	if (IS_ERR(clk)) {
> -		err = PTR_ERR(clk);
> -		dev_err(dev, "%s: failed to get %s err %d",
> -				__func__, name, err);
> -	} else {
> +	if (!IS_ERR(clk)) {
>   		*clk_out = clk;
> +		return 0;
>   	}
>   
> +	err = PTR_ERR(clk);
> +
> +	if (optional && err == -ENOENT) {
> +		*clk_out = NULL;
> +		return 0;
> +	}
> +
> +	if (err != -EPROBE_DEFER)
> +		dev_err(dev, "failed to get %s err %d",
> +				name, err);
> +
>   	return err;
>   }
>   
> @@ -113,11 +121,9 @@ static void ufs_qcom_disable_lane_clks(struct ufs_qcom_host *host)
>   	if (!host->is_lane_clks_enabled)
>   		return;
>   
> -	if (host->hba->lanes_per_direction > 1)
> -		clk_disable_unprepare(host->tx_l1_sync_clk);
> +	clk_disable_unprepare(host->tx_l1_sync_clk);
>   	clk_disable_unprepare(host->tx_l0_sync_clk);
> -	if (host->hba->lanes_per_direction > 1)
> -		clk_disable_unprepare(host->rx_l1_sync_clk);
> +	clk_disable_unprepare(host->rx_l1_sync_clk);
>   	clk_disable_unprepare(host->rx_l0_sync_clk);
>   
>   	host->is_lane_clks_enabled = false;
> @@ -141,24 +147,21 @@ static int ufs_qcom_enable_lane_clks(struct ufs_qcom_host *host)
>   	if (err)
>   		goto disable_rx_l0;
>   
> -	if (host->hba->lanes_per_direction > 1) {
> -		err = ufs_qcom_host_clk_enable(dev, "rx_lane1_sync_clk",
> +	err = ufs_qcom_host_clk_enable(dev, "rx_lane1_sync_clk",
>   			host->rx_l1_sync_clk);
> -		if (err)
> -			goto disable_tx_l0;
> +	if (err)
> +		goto disable_tx_l0;
>   
> -		err = ufs_qcom_host_clk_enable(dev, "tx_lane1_sync_clk",
> +	err = ufs_qcom_host_clk_enable(dev, "tx_lane1_sync_clk",
>   			host->tx_l1_sync_clk);
> -		if (err)
> -			goto disable_rx_l1;
> -	}
> +	if (err)
> +		goto disable_rx_l1;
>   
>   	host->is_lane_clks_enabled = true;
>   	goto out;
>   
>   disable_rx_l1:
> -	if (host->hba->lanes_per_direction > 1)
> -		clk_disable_unprepare(host->rx_l1_sync_clk);
> +	clk_disable_unprepare(host->rx_l1_sync_clk);
>   disable_tx_l0:
>   	clk_disable_unprepare(host->tx_l0_sync_clk);
>   disable_rx_l0:
> @@ -172,25 +175,25 @@ static int ufs_qcom_init_lane_clks(struct ufs_qcom_host *host)
>   	int err = 0;
>   	struct device *dev = host->hba->dev;
>   
> -	err = ufs_qcom_host_clk_get(dev,
> -			"rx_lane0_sync_clk", &host->rx_l0_sync_clk);
> +	err = ufs_qcom_host_clk_get(dev, "rx_lane0_sync_clk",
> +					&host->rx_l0_sync_clk, false);
>   	if (err)
>   		goto out;
>   
> -	err = ufs_qcom_host_clk_get(dev,
> -			"tx_lane0_sync_clk", &host->tx_l0_sync_clk);
> +	err = ufs_qcom_host_clk_get(dev, "tx_lane0_sync_clk",
> +					&host->tx_l0_sync_clk, false);
>   	if (err)
>   		goto out;
>   
>   	/* In case of single lane per direction, don't read lane1 clocks */
>   	if (host->hba->lanes_per_direction > 1) {
>   		err = ufs_qcom_host_clk_get(dev, "rx_lane1_sync_clk",
> -			&host->rx_l1_sync_clk);
> +			&host->rx_l1_sync_clk, false);
>   		if (err)
>   			goto out;
>   
>   		err = ufs_qcom_host_clk_get(dev, "tx_lane1_sync_clk",
> -			&host->tx_l1_sync_clk);
> +			&host->tx_l1_sync_clk, true);
>   	}
>   out:
>   	return err;

Reviewed-by: Vivek Gautam <vivek.gautam@codeaurora.org>

Best regards
Vivek

Re: [PATCH v3 1/1] scsi: ufs: make UFS Tx lane1 clock optional for QCOM platforms

[cang]

Hi,

On 2018-10-12 14:10, Vivek Gautam wrote:
> On 10/12/2018 6:42 AM, Can Guo wrote:
>> From: Venkat Gopalakrishnan <venkatg@codeaurora.org>
>> 
>> Per Qcom's UFS host controller HW design, the UFS Tx lane1 clock could 
>> be
>> muxed with Tx lane0 clock, hence keep Tx lane1 clock optional by 
>> ignoring
>> it if it is not provided in device tree. This change also performs 
>> some
>> cleanup to lanes per direction checks when enable/disable lane clocks 
>> just
>> for symmetry.
>> 
>> Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
>> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>> ---
>> Changes since v2:
>> - Incorporated review comments from Doug.
>> 
>> Changes since v1:
>> - Incorporated review comments from Doug.
>> - Update the commit title and commit message.
>> 
>>   drivers/scsi/ufs/ufs-qcom.c | 55 
>> ++++++++++++++++++++++++---------------------
>>   1 file changed, 29 insertions(+), 26 deletions(-)
>> 
>> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
>> index 2b38db2..dbc84cb 100644
>> --- a/drivers/scsi/ufs/ufs-qcom.c
>> +++ b/drivers/scsi/ufs/ufs-qcom.c
>> @@ -79,20 +79,28 @@ static int ufs_qcom_get_connected_tx_lanes(struct 
>> ufs_hba *hba, u32 *tx_lanes)
>>   }
>>     static int ufs_qcom_host_clk_get(struct device *dev,
>> -		const char *name, struct clk **clk_out)
>> +		const char *name, struct clk **clk_out, bool optional)
>>   {
>>   	struct clk *clk;
>>   	int err = 0;
>>     	clk = devm_clk_get(dev, name);
>> -	if (IS_ERR(clk)) {
>> -		err = PTR_ERR(clk);
>> -		dev_err(dev, "%s: failed to get %s err %d",
>> -				__func__, name, err);
>> -	} else {
>> +	if (!IS_ERR(clk)) {
>>   		*clk_out = clk;
>> +		return 0;
>>   	}
>>   +	err = PTR_ERR(clk);
>> +
>> +	if (optional && err == -ENOENT) {
>> +		*clk_out = NULL;
>> +		return 0;
>> +	}
>> +
>> +	if (err != -EPROBE_DEFER)
>> +		dev_err(dev, "failed to get %s err %d",
>> +				name, err);
>> +
>>   	return err;
>>   }
>>   @@ -113,11 +121,9 @@ static void ufs_qcom_disable_lane_clks(struct 
>> ufs_qcom_host *host)
>>   	if (!host->is_lane_clks_enabled)
>>   		return;
>>   -	if (host->hba->lanes_per_direction > 1)
>> -		clk_disable_unprepare(host->tx_l1_sync_clk);
>> +	clk_disable_unprepare(host->tx_l1_sync_clk);
>>   	clk_disable_unprepare(host->tx_l0_sync_clk);
>> -	if (host->hba->lanes_per_direction > 1)
>> -		clk_disable_unprepare(host->rx_l1_sync_clk);
>> +	clk_disable_unprepare(host->rx_l1_sync_clk);
>>   	clk_disable_unprepare(host->rx_l0_sync_clk);
>>     	host->is_lane_clks_enabled = false;
>> @@ -141,24 +147,21 @@ static int ufs_qcom_enable_lane_clks(struct 
>> ufs_qcom_host *host)
>>   	if (err)
>>   		goto disable_rx_l0;
>>   -	if (host->hba->lanes_per_direction > 1) {
>> -		err = ufs_qcom_host_clk_enable(dev, "rx_lane1_sync_clk",
>> +	err = ufs_qcom_host_clk_enable(dev, "rx_lane1_sync_clk",
>>   			host->rx_l1_sync_clk);
>> -		if (err)
>> -			goto disable_tx_l0;
>> +	if (err)
>> +		goto disable_tx_l0;
>>   -		err = ufs_qcom_host_clk_enable(dev, "tx_lane1_sync_clk",
>> +	err = ufs_qcom_host_clk_enable(dev, "tx_lane1_sync_clk",
>>   			host->tx_l1_sync_clk);
>> -		if (err)
>> -			goto disable_rx_l1;
>> -	}
>> +	if (err)
>> +		goto disable_rx_l1;
>>     	host->is_lane_clks_enabled = true;
>>   	goto out;
>>     disable_rx_l1:
>> -	if (host->hba->lanes_per_direction > 1)
>> -		clk_disable_unprepare(host->rx_l1_sync_clk);
>> +	clk_disable_unprepare(host->rx_l1_sync_clk);
>>   disable_tx_l0:
>>   	clk_disable_unprepare(host->tx_l0_sync_clk);
>>   disable_rx_l0:
>> @@ -172,25 +175,25 @@ static int ufs_qcom_init_lane_clks(struct 
>> ufs_qcom_host *host)
>>   	int err = 0;
>>   	struct device *dev = host->hba->dev;
>>   -	err = ufs_qcom_host_clk_get(dev,
>> -			"rx_lane0_sync_clk", &host->rx_l0_sync_clk);
>> +	err = ufs_qcom_host_clk_get(dev, "rx_lane0_sync_clk",
>> +					&host->rx_l0_sync_clk, false);
>>   	if (err)
>>   		goto out;
>>   -	err = ufs_qcom_host_clk_get(dev,
>> -			"tx_lane0_sync_clk", &host->tx_l0_sync_clk);
>> +	err = ufs_qcom_host_clk_get(dev, "tx_lane0_sync_clk",
>> +					&host->tx_l0_sync_clk, false);
>>   	if (err)
>>   		goto out;
>>     	/* In case of single lane per direction, don't read lane1 clocks 
>> */
>>   	if (host->hba->lanes_per_direction > 1) {
>>   		err = ufs_qcom_host_clk_get(dev, "rx_lane1_sync_clk",
>> -			&host->rx_l1_sync_clk);
>> +			&host->rx_l1_sync_clk, false);
>>   		if (err)
>>   			goto out;
>>     		err = ufs_qcom_host_clk_get(dev, "tx_lane1_sync_clk",
>> -			&host->tx_l1_sync_clk);
>> +			&host->tx_l1_sync_clk, true);
>>   	}
>>   out:
>>   	return err;
> 
> Reviewed-by: Vivek Gautam <vivek.gautam@codeaurora.org>
> 
> Best regards
> Vivek

Thank you Vivek.

-Can Guo

Re: [PATCH v3 1/1] scsi: ufs: make UFS Tx lane1 clock optional for QCOM platforms

[Doug Anderson]

Hi,

On Thu, Oct 11, 2018 at 6:12 PM Can Guo <cang@codeaurora.org> wrote:
> +       if (err != -EPROBE_DEFER)
> +               dev_err(dev, "failed to get %s err %d",
> +                               name, err);

I wouldn't spin just for this, but if you spin for some other reason
you could move the above "dev_err" onto one line now.  Sorry: I should
have noticed that / done that on my patch...


> @@ -141,24 +147,21 @@ static int ufs_qcom_enable_lane_clks(struct ufs_qcom_host *host)

Idea for a future patch: now that I look at what's left of this
function you're basically re-implementing clk_bulk_prepare_enable()
and clk_bulk_disable_unprepare() now.  I bet your code would be
cleaner / nicer by switching to that.

...possibly you might need to improve the clk_bulk_get() API to allow
for some clock to be optional, but that would be a pretty easy patch
to post up.

In any case I think it's better to do the clk_bulk switch in a future
/ separate patch, so:

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>


-Doug

Re: [PATCH v3 1/1] scsi: ufs: make UFS Tx lane1 clock optional for QCOM platforms

[cang]

On 2018-10-13 00:55, Doug Anderson wrote:
> Hi,
> 
> On Thu, Oct 11, 2018 at 6:12 PM Can Guo <cang@codeaurora.org> wrote:
>> +       if (err != -EPROBE_DEFER)
>> +               dev_err(dev, "failed to get %s err %d",
>> +                               name, err);
> 
> I wouldn't spin just for this, but if you spin for some other reason
> you could move the above "dev_err" onto one line now.  Sorry: I should
> have noticed that / done that on my patch...
> 
> 

Yeah... I didn't notice it too. Shall push a new one to address it.

>> @@ -141,24 +147,21 @@ static int ufs_qcom_enable_lane_clks(struct 
>> ufs_qcom_host *host)
> 
> Idea for a future patch: now that I look at what's left of this
> function you're basically re-implementing clk_bulk_prepare_enable()
> and clk_bulk_disable_unprepare() now.  I bet your code would be
> cleaner / nicer by switching to that.
> 
> ...possibly you might need to improve the clk_bulk_get() API to allow
> for some clock to be optional, but that would be a pretty easy patch
> to post up.
> 
> In any case I think it's better to do the clk_bulk switch in a future
> / separate patch, so:
> 
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> Tested-by: Douglas Anderson <dianders@chromium.org>
> 
> 
> -Doug

That is a good idea, I shall follow up after this one is merged.

Thank you.
-Can Guo