[2/6] usb: cdns3-ti: move reg writes from probe into an init_hw helper
Commit Message
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
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) {
>
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) {
> >
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!
@@ -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) {