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authorSinan Kaya <okaya@codeaurora.org>2016-07-19 09:01:44 -0400
committerAlex Williamson <alex.williamson@redhat.com>2016-07-19 10:26:41 -0600
commita12a9368e192d56175e49d69360d861025a0f6f7 (patch)
tree79fc72bc9350f516664ebc434c2acdd11192c2ca /drivers/vfio
parentdc5542fb115a9576493831160e31d355b58541d7 (diff)
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>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/platform/vfio_platform_common.c64
-rw-r--r--drivers/vfio/platform/vfio_platform_private.h1
2 files changed, 60 insertions, 5 deletions
diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index 307d61d2aea2..716f421d1b01 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 +50,27 @@ 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;
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 71ed7d1c1b7d..ba9e4f8b0746 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;