Messages in this thread | | | Date | Mon, 18 Jul 2016 20:16:50 -0400 | From | okaya@codeauro ... | Subject | Re: [PATCH V10 4/9] vfio: platform: add support for ACPI probe |
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On 2016-07-18 20:00, Alex Williamson wrote: > On Mon, 18 Jul 2016 19:09:22 -0400 > Sinan Kaya <okaya@codeaurora.org> wrote: > >> The code is using the compatible DT string to associate a reset driver >> with the actual device itself. The compatible string does not exist on >> ACPI based systems. HID is the unique identifier for a device driver >> instead. >> >> Signed-off-by: Sinan Kaya <okaya@codeaurora.org> >> --- >> drivers/vfio/platform/vfio_platform_common.c | 69 >> +++++++++++++++++++++++++-- >> drivers/vfio/platform/vfio_platform_private.h | 1 + >> 2 files changed, 65 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/vfio/platform/vfio_platform_common.c >> b/drivers/vfio/platform/vfio_platform_common.c >> index 6be92c3..a5299f6 100644 >> --- a/drivers/vfio/platform/vfio_platform_common.c >> +++ b/drivers/vfio/platform/vfio_platform_common.c >> @@ -13,6 +13,7 @@ >> */ >> >> #include <linux/device.h> >> +#include <linux/acpi.h> >> #include <linux/iommu.h> >> #include <linux/module.h> >> #include <linux/mutex.h> >> @@ -49,6 +50,32 @@ static vfio_platform_reset_fn_t >> vfio_platform_lookup_reset(const char *compat, >> return reset_fn; >> } >> >> +static int vfio_platform_acpi_probe(struct vfio_platform_device >> *vdev, >> + struct device *dev) >> +{ >> + struct acpi_device *adev; >> + >> + if (acpi_disabled) >> + return -EPERM; >> + >> + adev = ACPI_COMPANION(dev); > > I didn't necessarily have a problem with this being set in the > declaration.
I think this is better. If ACPI is disabled, it is dangerous to call an ACPI API.
> >> + if (!adev) { >> + pr_err("VFIO: ACPI companion device not found for %s\n", >> + vdev->name); >> + return -ENODEV; >> + } >> + >> +#ifdef CONFIG_ACPI >> + vdev->acpihid = acpi_device_hid(adev); >> + if (!vdev->acpihid) { >> + pr_err("VFIO: cannot find ACPI HID for %s\n", >> + vdev->name); >> + return -EINVAL; >> + } >> +#endif >> + return WARN_ON(!vdev->acpihid) ? -ENOENT : 0; > > ?!?! The point was that that entire if{} branch is unnecessary. The > WARN_ON handles the (impossible) case of !vdev->acpihid. We just need: > > #ifdef CONFIG_ACPI > vdev->acpihid = acpi_device_hid(adev); > #endif > return WARN_ON(!vdev->acpihid) ? -ENOENT : 0; >
OK, got it now. I thought you were trying to get rid of #else
> nit, might make sense to replace EPERM with ENOENT and use EINVAL here. >
Sure, will take carr of it.
Anything else I need to take care of?
>> +} >> + >> static bool vfio_platform_has_reset(struct vfio_platform_device >> *vdev) >> { >> return vdev->of_reset ? true : false; >> @@ -547,6 +574,37 @@ static const struct vfio_device_ops >> vfio_platform_ops = { >> .mmap = vfio_platform_mmap, >> }; >> >> +int vfio_platform_of_probe(struct vfio_platform_device *vdev, >> + struct device *dev) >> +{ >> + int ret; >> + >> + ret = device_property_read_string(dev, "compatible", >> + &vdev->compat); >> + if (ret) >> + pr_err("VFIO: cannot retrieve compat for %s\n", >> + vdev->name); >> + >> + return ret; >> +} >> + >> +/* >> + * There can be two kernel build combinations. One build where >> + * ACPI is not selected in Kconfig and another one with the ACPI >> Kconfig. >> + * >> + * In the first case, vfio_platform_acpi_probe will return since >> + * acpi_disabled is 1. DT user will not see any kind of messages from >> + * ACPI. >> + * >> + * In the second case, both DT and ACPI is compiled in but the system >> is >> + * booting with any of these combinations. >> + * >> + * If the firmware is DT type, then acpi_disabled is 1. The ACPI >> probe routine >> + * terminates immediately without any messages. >> + * >> + * If the firmware is ACPI type, then acpi_disabled is 0. All other >> checks are >> + * valid checks. We cannot claim that this system is DT. >> + */ >> int vfio_platform_probe_common(struct vfio_platform_device *vdev, >> struct device *dev) >> { >> @@ -556,11 +614,12 @@ int vfio_platform_probe_common(struct >> vfio_platform_device *vdev, >> if (!vdev) >> return -EINVAL; >> >> - ret = device_property_read_string(dev, "compatible", &vdev->compat); >> - if (ret) { >> - pr_err("VFIO: cannot retrieve compat for %s\n", vdev->name); >> - return -EINVAL; >> - } >> + ret = vfio_platform_acpi_probe(vdev, dev); >> + if (ret) >> + ret = vfio_platform_of_probe(vdev, dev); >> + >> + if (ret) >> + return ret; >> >> vdev->device = dev; >> >> diff --git a/drivers/vfio/platform/vfio_platform_private.h >> b/drivers/vfio/platform/vfio_platform_private.h >> index 71ed7d1..ba9e4f8 100644 >> --- a/drivers/vfio/platform/vfio_platform_private.h >> +++ b/drivers/vfio/platform/vfio_platform_private.h >> @@ -58,6 +58,7 @@ struct vfio_platform_device { >> struct mutex igate; >> struct module *parent_module; >> const char *compat; >> + const char *acpihid; >> struct module *reset_module; >> struct device *device; >>
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