diff mbox series

[2/6] usb: cdns3-ti: move reg writes from probe into an init_hw helper

Message ID 20231113-j7200-usb-suspend-v1-2-ad1ee714835c@bootlin.com (mailing list archive)
State New, archived
Headers show
Series usb: cdns: fix suspend on J7200 by assuming reset on resume | expand

Commit Message

Théo Lebrun Nov. 13, 2023, 2:26 p.m. UTC 
The hardware initialisation register write sequence is only used at
probe. To support suspend/resume with a controller losing power, we
must redo this sequence of writes.

Extract the register write sequence to a new cdns_ti_init_hw function to
reuse it later down the road, at resume.

We keep the devicetree-parsing aspect of the sequence in probe & add a
new field in the private struct to remember the USB2 refclk rate code
computation result.

Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
---
 drivers/usb/cdns3/cdns3-ti.c | 76 ++++++++++++++++++++++++--------------------
 1 file changed, 41 insertions(+), 35 deletions(-)

Comments

Roger Quadros Nov. 15, 2023, 11:33 a.m. UTC | #1 
Hi Théo,

On 13/11/2023 16:26, Théo Lebrun wrote:
> The hardware initialisation register write sequence is only used at
> probe. To support suspend/resume with a controller losing power, we
> must redo this sequence of writes.
> 
> Extract the register write sequence to a new cdns_ti_init_hw function to
> reuse it later down the road, at resume.
> 
> We keep the devicetree-parsing aspect of the sequence in probe & add a
> new field in the private struct to remember the USB2 refclk rate code
> computation result.
> 
> Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
> ---
>  drivers/usb/cdns3/cdns3-ti.c | 76 ++++++++++++++++++++++++--------------------
>  1 file changed, 41 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/usb/cdns3/cdns3-ti.c b/drivers/usb/cdns3/cdns3-ti.c
> index 5945c4b1e11f..c331bcd2faeb 100644
> --- a/drivers/usb/cdns3/cdns3-ti.c
> +++ b/drivers/usb/cdns3/cdns3-ti.c
> @@ -57,6 +57,7 @@ struct cdns_ti {
>  	unsigned vbus_divider:1;
>  	struct clk *usb2_refclk;
>  	struct clk *lpm_clk;
> +	int usb2_refclk_rate_code;
>  };
>  
>  static const int cdns_ti_rate_table[] = {	/* in KHZ */
> @@ -85,15 +86,50 @@ static inline void cdns_ti_writel(struct cdns_ti *data, u32 offset, u32 value)
>  	writel(value, data->usbss + offset);
>  }
>  
> +static void cdns_ti_init_hw(struct cdns_ti *data)
> +{
> +	u32 reg;
> +
> +	/* assert RESET */
> +	reg = cdns_ti_readl(data, USBSS_W1);
> +	reg &= ~USBSS_W1_PWRUP_RST;
> +	cdns_ti_writel(data, USBSS_W1, reg);
> +
> +	/* set static config */
> +	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> +	reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
> +	reg |= data->usb2_refclk_rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
> +
> +	reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
> +	if (data->vbus_divider)
> +		reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
> +
> +	cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
> +	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> +
> +	/* set USB2_ONLY mode if requested */
> +	reg = cdns_ti_readl(data, USBSS_W1);
> +	if (data->usb2_only)
> +		reg |= USBSS_W1_USB2_ONLY;
> +
> +	/* set default modestrap */
> +	reg |= USBSS_W1_MODESTRAP_SEL;
> +	reg &= ~USBSS_W1_MODESTRAP_MASK;
> +	reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
> +	cdns_ti_writel(data, USBSS_W1, reg);
> +
> +	/* de-assert RESET */
> +	reg |= USBSS_W1_PWRUP_RST;
> +	cdns_ti_writel(data, USBSS_W1, reg);
> +}
> +
>  static int cdns_ti_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct device_node *node = pdev->dev.of_node;
>  	struct cdns_ti *data;
> -	int error;
> -	u32 reg;
> -	int rate_code, i;
>  	unsigned long rate;
> +	int error, i;

Should we leave rate_code and get rid of i?

>  
>  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>  	if (!data)
> @@ -133,8 +169,6 @@ static int cdns_ti_probe(struct platform_device *pdev)
>  		return -EINVAL;
>  	}
>  
> -	rate_code = i;
> -
>  	pm_runtime_enable(dev);
>  	error = pm_runtime_get_sync(dev)>  	if (error < 0) {
> @@ -142,39 +176,11 @@ static int cdns_ti_probe(struct platform_device *pdev)
>  		goto err;
>  	}
>  
> -	/* assert RESET */
> -	reg = cdns_ti_readl(data, USBSS_W1);
> -	reg &= ~USBSS_W1_PWRUP_RST;
> -	cdns_ti_writel(data, USBSS_W1, reg);
> -
> -	/* set static config */
> -	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> -	reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
> -	reg |= rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
> -
> -	reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
>  	data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
> -	if (data->vbus_divider)
> -		reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
> -
> -	cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
> -	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> -
> -	/* set USB2_ONLY mode if requested */
> -	reg = cdns_ti_readl(data, USBSS_W1);
>  	data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");
> -	if (data->usb2_only)
> -		reg |= USBSS_W1_USB2_ONLY;
> -
> -	/* set default modestrap */
> -	reg |= USBSS_W1_MODESTRAP_SEL;
> -	reg &= ~USBSS_W1_MODESTRAP_MASK;
> -	reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
> -	cdns_ti_writel(data, USBSS_W1, reg);
> +	data->usb2_refclk_rate_code = i;

because 'i' seems temporary.

>  
> -	/* de-assert RESET */
> -	reg |= USBSS_W1_PWRUP_RST;
> -	cdns_ti_writel(data, USBSS_W1, reg);
> +	cdns_ti_init_hw(data);
>  
>  	error = of_platform_populate(node, NULL, NULL, dev);
>  	if (error) {
>
Théo Lebrun Nov. 15, 2023, 2:23 p.m. UTC | #2 
Hello,

On Wed Nov 15, 2023 at 12:33 PM CET, Roger Quadros wrote:
> > --- a/drivers/usb/cdns3/cdns3-ti.c
> > +++ b/drivers/usb/cdns3/cdns3-ti.c

[...]

> >  static int cdns_ti_probe(struct platform_device *pdev)
> >  {
> >  	struct device *dev = &pdev->dev;
> >  	struct device_node *node = pdev->dev.of_node;
> >  	struct cdns_ti *data;
> > -	int error;
> > -	u32 reg;
> > -	int rate_code, i;
> >  	unsigned long rate;
> > +	int error, i;
>
> Should we leave rate_code and get rid of i?

I see your point about i being usually a temp variable. Using rate_code
instead of i means the for-loop becomes rather long (column 87) &
should ideally be split.

How about moving the data->usb2_refclk_rate_code assignment up, closer
to the computation of i? That way we don't reference i three blocks
down the road, seemingly out of nowhere.

Regards,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

------------------------------------------------------------------------

> >  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> >  	if (!data)
> > @@ -133,8 +169,6 @@ static int cdns_ti_probe(struct platform_device *pdev)
> >  		return -EINVAL;
> >  	}
> >  
> > -	rate_code = i;
> > -
> >  	pm_runtime_enable(dev);
> >  	error = pm_runtime_get_sync(dev)>  	if (error < 0) {
> > @@ -142,39 +176,11 @@ static int cdns_ti_probe(struct platform_device *pdev)
> >  		goto err;
> >  	}
> >  
> > -	/* assert RESET */
> > -	reg = cdns_ti_readl(data, USBSS_W1);
> > -	reg &= ~USBSS_W1_PWRUP_RST;
> > -	cdns_ti_writel(data, USBSS_W1, reg);
> > -
> > -	/* set static config */
> > -	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> > -	reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
> > -	reg |= rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
> > -
> > -	reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
> >  	data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
> > -	if (data->vbus_divider)
> > -		reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
> > -
> > -	cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
> > -	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
> > -
> > -	/* set USB2_ONLY mode if requested */
> > -	reg = cdns_ti_readl(data, USBSS_W1);
> >  	data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");
> > -	if (data->usb2_only)
> > -		reg |= USBSS_W1_USB2_ONLY;
> > -
> > -	/* set default modestrap */
> > -	reg |= USBSS_W1_MODESTRAP_SEL;
> > -	reg &= ~USBSS_W1_MODESTRAP_MASK;
> > -	reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
> > -	cdns_ti_writel(data, USBSS_W1, reg);
> > +	data->usb2_refclk_rate_code = i;
>
> because 'i' seems temporary.
>
> >  
> > -	/* de-assert RESET */
> > -	reg |= USBSS_W1_PWRUP_RST;
> > -	cdns_ti_writel(data, USBSS_W1, reg);
> > +	cdns_ti_init_hw(data);
> >  
> >  	error = of_platform_populate(node, NULL, NULL, dev);
> >  	if (error) {
> >
Roger Quadros Nov. 16, 2023, noon UTC | #3 
On 15/11/2023 16:23, Théo Lebrun wrote:
> Hello,
> 
> On Wed Nov 15, 2023 at 12:33 PM CET, Roger Quadros wrote:
>>> --- a/drivers/usb/cdns3/cdns3-ti.c
>>> +++ b/drivers/usb/cdns3/cdns3-ti.c
> 
> [...]
> 
>>>  static int cdns_ti_probe(struct platform_device *pdev)
>>>  {
>>>  	struct device *dev = &pdev->dev;
>>>  	struct device_node *node = pdev->dev.of_node;
>>>  	struct cdns_ti *data;
>>> -	int error;
>>> -	u32 reg;
>>> -	int rate_code, i;
>>>  	unsigned long rate;
>>> +	int error, i;
>>
>> Should we leave rate_code and get rid of i?
> 
> I see your point about i being usually a temp variable. Using rate_code
> instead of i means the for-loop becomes rather long (column 87) &
> should ideally be split.
> 
> How about moving the data->usb2_refclk_rate_code assignment up, closer
> to the computation of i? That way we don't reference i three blocks
> down the road, seemingly out of nowhere.

That is much better. Thanks!
diff mbox series

Patch

diff --git a/drivers/usb/cdns3/cdns3-ti.c b/drivers/usb/cdns3/cdns3-ti.c
index 5945c4b1e11f..c331bcd2faeb 100644
--- a/drivers/usb/cdns3/cdns3-ti.c
+++ b/drivers/usb/cdns3/cdns3-ti.c
@@ -57,6 +57,7 @@  struct cdns_ti {
 	unsigned vbus_divider:1;
 	struct clk *usb2_refclk;
 	struct clk *lpm_clk;
+	int usb2_refclk_rate_code;
 };
 
 static const int cdns_ti_rate_table[] = {	/* in KHZ */
@@ -85,15 +86,50 @@  static inline void cdns_ti_writel(struct cdns_ti *data, u32 offset, u32 value)
 	writel(value, data->usbss + offset);
 }
 
+static void cdns_ti_init_hw(struct cdns_ti *data)
+{
+	u32 reg;
+
+	/* assert RESET */
+	reg = cdns_ti_readl(data, USBSS_W1);
+	reg &= ~USBSS_W1_PWRUP_RST;
+	cdns_ti_writel(data, USBSS_W1, reg);
+
+	/* set static config */
+	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
+	reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
+	reg |= data->usb2_refclk_rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
+
+	reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
+	if (data->vbus_divider)
+		reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
+
+	cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
+	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
+
+	/* set USB2_ONLY mode if requested */
+	reg = cdns_ti_readl(data, USBSS_W1);
+	if (data->usb2_only)
+		reg |= USBSS_W1_USB2_ONLY;
+
+	/* set default modestrap */
+	reg |= USBSS_W1_MODESTRAP_SEL;
+	reg &= ~USBSS_W1_MODESTRAP_MASK;
+	reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
+	cdns_ti_writel(data, USBSS_W1, reg);
+
+	/* de-assert RESET */
+	reg |= USBSS_W1_PWRUP_RST;
+	cdns_ti_writel(data, USBSS_W1, reg);
+}
+
 static int cdns_ti_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct device_node *node = pdev->dev.of_node;
 	struct cdns_ti *data;
-	int error;
-	u32 reg;
-	int rate_code, i;
 	unsigned long rate;
+	int error, i;
 
 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
@@ -133,8 +169,6 @@  static int cdns_ti_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	rate_code = i;
-
 	pm_runtime_enable(dev);
 	error = pm_runtime_get_sync(dev);
 	if (error < 0) {
@@ -142,39 +176,11 @@  static int cdns_ti_probe(struct platform_device *pdev)
 		goto err;
 	}
 
-	/* assert RESET */
-	reg = cdns_ti_readl(data, USBSS_W1);
-	reg &= ~USBSS_W1_PWRUP_RST;
-	cdns_ti_writel(data, USBSS_W1, reg);
-
-	/* set static config */
-	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
-	reg &= ~USBSS1_STATIC_PLL_REF_SEL_MASK;
-	reg |= rate_code << USBSS1_STATIC_PLL_REF_SEL_SHIFT;
-
-	reg &= ~USBSS1_STATIC_VBUS_SEL_MASK;
 	data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
-	if (data->vbus_divider)
-		reg |= 1 << USBSS1_STATIC_VBUS_SEL_SHIFT;
-
-	cdns_ti_writel(data, USBSS_STATIC_CONFIG, reg);
-	reg = cdns_ti_readl(data, USBSS_STATIC_CONFIG);
-
-	/* set USB2_ONLY mode if requested */
-	reg = cdns_ti_readl(data, USBSS_W1);
 	data->usb2_only = device_property_read_bool(dev, "ti,usb2-only");
-	if (data->usb2_only)
-		reg |= USBSS_W1_USB2_ONLY;
-
-	/* set default modestrap */
-	reg |= USBSS_W1_MODESTRAP_SEL;
-	reg &= ~USBSS_W1_MODESTRAP_MASK;
-	reg |= USBSS_MODESTRAP_MODE_NONE << USBSS_W1_MODESTRAP_SHIFT;
-	cdns_ti_writel(data, USBSS_W1, reg);
+	data->usb2_refclk_rate_code = i;
 
-	/* de-assert RESET */
-	reg |= USBSS_W1_PWRUP_RST;
-	cdns_ti_writel(data, USBSS_W1, reg);
+	cdns_ti_init_hw(data);
 
 	error = of_platform_populate(node, NULL, NULL, dev);
 	if (error) {