* [PATCH v1] usb: phy: tegra: Add clarifying comments about the shared registers
@ 2020-02-02 22:42 Dmitry Osipenko
2020-02-03 11:28 ` Thierry Reding
0 siblings, 1 reply; 3+ messages in thread
From: Dmitry Osipenko @ 2020-02-02 22:42 UTC (permalink / raw)
To: Greg Kroah-Hartman, Thierry Reding, Jonathan Hunter, Felipe Balbi
Cc: linux-usb, linux-tegra, linux-kernel
Tools like Coccinelle may erroneously recommend to use the
devm_platform_ioremap_resource() API for the registers mapping because
these tools are not aware about the implementation details of the driver.
Let's add a clarifying comments to the code, which should help to stop
future attempts to break the driver.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/usb/phy/phy-tegra-usb.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c
index 037e8eee737d..6153cc35aba0 100644
--- a/drivers/usb/phy/phy-tegra-usb.c
+++ b/drivers/usb/phy/phy-tegra-usb.c
@@ -969,6 +969,10 @@ static int utmi_phy_probe(struct tegra_usb_phy *tegra_phy,
return -ENXIO;
}
+ /*
+ * Note that UTMI pad registers are shared by all PHYs, therefore
+ * devm_platform_ioremap_resource() can't be used here.
+ */
tegra_phy->pad_regs = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
if (!tegra_phy->pad_regs) {
@@ -1087,6 +1091,10 @@ static int tegra_usb_phy_probe(struct platform_device *pdev)
return -ENXIO;
}
+ /*
+ * Note that PHY and USB controller are using shared registers,
+ * therefore devm_platform_ioremap_resource() can't be used here.
+ */
tegra_phy->regs = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
if (!tegra_phy->regs) {
--
2.24.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] usb: phy: tegra: Add clarifying comments about the shared registers
2020-02-02 22:42 [PATCH v1] usb: phy: tegra: Add clarifying comments about the shared registers Dmitry Osipenko
@ 2020-02-03 11:28 ` Thierry Reding
2020-02-03 16:26 ` Dmitry Osipenko
0 siblings, 1 reply; 3+ messages in thread
From: Thierry Reding @ 2020-02-03 11:28 UTC (permalink / raw)
To: Dmitry Osipenko
Cc: Greg Kroah-Hartman, Jonathan Hunter, Felipe Balbi, linux-usb,
linux-tegra, linux-kernel
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On Mon, Feb 03, 2020 at 01:42:59AM +0300, Dmitry Osipenko wrote:
> Tools like Coccinelle may erroneously recommend to use the
> devm_platform_ioremap_resource() API for the registers mapping because
> these tools are not aware about the implementation details of the driver.
> Let's add a clarifying comments to the code, which should help to stop
> future attempts to break the driver.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/usb/phy/phy-tegra-usb.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c
> index 037e8eee737d..6153cc35aba0 100644
> --- a/drivers/usb/phy/phy-tegra-usb.c
> +++ b/drivers/usb/phy/phy-tegra-usb.c
> @@ -969,6 +969,10 @@ static int utmi_phy_probe(struct tegra_usb_phy *tegra_phy,
> return -ENXIO;
> }
>
> + /*
> + * Note that UTMI pad registers are shared by all PHYs, therefore
> + * devm_platform_ioremap_resource() can't be used here.
> + */
> tegra_phy->pad_regs = devm_ioremap(&pdev->dev, res->start,
> resource_size(res));
> if (!tegra_phy->pad_regs) {
> @@ -1087,6 +1091,10 @@ static int tegra_usb_phy_probe(struct platform_device *pdev)
> return -ENXIO;
> }
>
> + /*
> + * Note that PHY and USB controller are using shared registers,
> + * therefore devm_platform_ioremap_resource() can't be used here.
> + */
> tegra_phy->regs = devm_ioremap(&pdev->dev, res->start,
> resource_size(res));
> if (!tegra_phy->regs) {
I'm not sure it's really going to stop *all* attempts. But at least for
people that go through the trouble of reading the comments, yes, this
should do the trick, so:
Acked-by: Thierry Reding <treding@nvidia.com>
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v1] usb: phy: tegra: Add clarifying comments about the shared registers
2020-02-03 11:28 ` Thierry Reding
@ 2020-02-03 16:26 ` Dmitry Osipenko
0 siblings, 0 replies; 3+ messages in thread
From: Dmitry Osipenko @ 2020-02-03 16:26 UTC (permalink / raw)
To: Thierry Reding
Cc: Greg Kroah-Hartman, Jonathan Hunter, Felipe Balbi, linux-usb,
linux-tegra, linux-kernel
03.02.2020 14:28, Thierry Reding пишет:
> On Mon, Feb 03, 2020 at 01:42:59AM +0300, Dmitry Osipenko wrote:
>> Tools like Coccinelle may erroneously recommend to use the
>> devm_platform_ioremap_resource() API for the registers mapping because
>> these tools are not aware about the implementation details of the driver.
>> Let's add a clarifying comments to the code, which should help to stop
>> future attempts to break the driver.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>> drivers/usb/phy/phy-tegra-usb.c | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>>
>> diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c
>> index 037e8eee737d..6153cc35aba0 100644
>> --- a/drivers/usb/phy/phy-tegra-usb.c
>> +++ b/drivers/usb/phy/phy-tegra-usb.c
>> @@ -969,6 +969,10 @@ static int utmi_phy_probe(struct tegra_usb_phy *tegra_phy,
>> return -ENXIO;
>> }
>>
>> + /*
>> + * Note that UTMI pad registers are shared by all PHYs, therefore
>> + * devm_platform_ioremap_resource() can't be used here.
>> + */
>> tegra_phy->pad_regs = devm_ioremap(&pdev->dev, res->start,
>> resource_size(res));
>> if (!tegra_phy->pad_regs) {
>> @@ -1087,6 +1091,10 @@ static int tegra_usb_phy_probe(struct platform_device *pdev)
>> return -ENXIO;
>> }
>>
>> + /*
>> + * Note that PHY and USB controller are using shared registers,
>> + * therefore devm_platform_ioremap_resource() can't be used here.
>> + */
>> tegra_phy->regs = devm_ioremap(&pdev->dev, res->start,
>> resource_size(res));
>> if (!tegra_phy->regs) {
>
> I'm not sure it's really going to stop *all* attempts. But at least for
> people that go through the trouble of reading the comments, yes, this
> should do the trick, so:
>
> Acked-by: Thierry Reding <treding@nvidia.com>
Will see, thanks :)
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-02-02 22:42 [PATCH v1] usb: phy: tegra: Add clarifying comments about the shared registers Dmitry Osipenko
2020-02-03 11:28 ` Thierry Reding
2020-02-03 16:26 ` Dmitry Osipenko
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