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vfio: platform: add support for ACPI probe 

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>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Sinan Kaya 2016-07-19 09:01:44 -04:00 committed by Alex Williamson
parent dc5542fb11
commit a12a9368e1
2 changed files with 60 additions and 5 deletions
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64
drivers/vfio/platform/vfio_platform_common.c
View File

@ -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 +50,27 @@ 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 -ENOENT;
adev = ACPI_COMPANION(dev);
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);
#endif
return WARN_ON(!vdev->acpihid) ? -EINVAL : 0;
}
static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
{
return vdev->of_reset ? true : false;
@ -547,6 +569,37 @@ 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 +609,12 @@ 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;

1
drivers/vfio/platform/vfio_platform_private.h
View File

@ -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;