Hi Philipp,
On Wed, Feb 21, 2018 at 5:51 PM, Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> wrote:
> I have a suggestion to avoid having to use the IS_ERR_OR_NULL macro, see
> below:
>
> On Tue, 2018-02-13 at 17:36 +0100, Geert Uytterhoeven wrote:
>> Vfio-platform requires reset support, provided either by ACPI, or, on DT
>> platforms, by a device-specific reset driver matching against the
>> device's compatible value.
>>
>> On many SoCs, devices are connected to an SoC-internal reset controller,
>> and can be reset in a generic way. Hence add support to reset such
>> devices using the reset controller subsystem, provided the reset
>> hierarchy is described correctly in DT using the "resets" property.
>>
>> Devices that require a more complex reset procedure can still
>> provide a device-specific reset driver, as that takes precedence.
>>
>> Note that this functionality depends on CONFIG_RESET_CONTROLLER=y, and
>> becomes a no-op if reset controller support is disabled.
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
>> ---
>> drivers/vfio/platform/vfio_platform_common.c | 23 +++++++++++++++++++++--
>> drivers/vfio/platform/vfio_platform_private.h | 1 +
>> 2 files changed, 22 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
>> index b60bb5326668498c..5d1e48f96e423508 100644
>> --- a/drivers/vfio/platform/vfio_platform_common.c
>> +++ b/drivers/vfio/platform/vfio_platform_common.c
>> @@ -17,6 +17,7 @@
>> #include <linux/iommu.h>
>> #include <linux/module.h>
>> #include <linux/mutex.h>
>> +#include <linux/reset.h>
>> #include <linux/slab.h>
>> #include <linux/types.h>
>> #include <linux/uaccess.h>
>> @@ -112,7 +113,13 @@ static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
>> if (VFIO_PLATFORM_IS_ACPI(vdev))
>> return vfio_platform_acpi_has_reset(vdev);
>>
>> - return vdev->of_reset ? true : false;
>> + if (vdev->of_reset)
>> + return true;
>> +
>> + if (!IS_ERR_OR_NULL(vdev->reset_control))
>> + return true;
>
> I'd avoid storing error values in vdev->reset_control at all, so this
> could be:
>
> if (vdev->reset_control)
> return true;
Thanks, much better!
>> @@ -127,8 +134,15 @@ static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
>> vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
>> &vdev->reset_module);
>> }
>> + if (vdev->of_reset)
>> + return 0;
>> +
>> + vdev->reset_control = __of_reset_control_get(vdev->device->of_node,
>> + NULL, 0, false, false);
>> + if (!IS_ERR(vdev->reset_control))
>> + return 0;
>
> if you assign to a local variable first here:
>
> struct reset_control *rstc;
>
> ...
>
> rstc = of_reset_control_get_exclusive(vdev->device->of_node, NULL);
> if (!IS_ERR(rstc)) {
> vdev->reset_control = rstc;
> return 0;
> }
>
> Also, please don't use __of_reset_control_get directly.
OK, apparently I didn't read <linux/reset.h> beyond the first #else...
>> @@ -217,6 +233,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
>> } else if (vdev->of_reset) {
>> dev_info(vdev->device, "reset\n");
>> return vdev->of_reset(vdev);
>> + } else if (!IS_ERR_OR_NULL(vdev->reset_control)) {
>> + dev_info(vdev->device, "reset\n");
>> + return reset_control_reset(vdev->reset_control);
>
> } else {
> if (vdev->reset_control)
> dev_info(vdev->device, "reset\n");
> return reset_control_reset(vdev->reset_control);
>
>> }
I'd like to keep the "else if", as that's the pattern used by the blocks above.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
