[PATCH V4 1/2] vfio, platform: add support for ACPI during probe and reset

Sinan Kaya
2016-05-01T21:07:51Z

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.

When ACPI is enabled, the change will query the presence of _RST method
and will call it instead of querying an external reset driver.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
drivers/vfio/platform/vfio_platform_common.c | 176 +++++++++++++++++++++-----
drivers/vfio/platform/vfio_platform_private.h | 7 +-
2 files changed, 147 insertions(+), 36 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index e65b142..528ec04 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>
@@ -41,7 +42,7 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
if (!strcmp(iter->compat, compat) &&
try_module_get(iter->owner)) {
*module = iter->owner;
- reset_fn = iter->reset;
+ reset_fn = iter->of_reset;
break;
}
}
@@ -49,20 +50,111 @@ static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
return reset_fn;
}

-static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
+
+#ifdef CONFIG_ACPI
+int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
+ struct device *dev)
{
- vdev->reset = vfio_platform_lookup_reset(vdev->compat,
- &vdev->reset_module);
- if (!vdev->reset) {
- request_module("vfio-reset:%s", vdev->compat);
- vdev->reset = vfio_platform_lookup_reset(vdev->compat,
- &vdev->reset_module);
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+
+ if (acpi_disabled)
+ return -ENODEV;
+
+ if (!adev)
+ return -ENODEV;
+
+ vdev->acpihid = acpi_device_hid(adev);
+ if (!vdev->acpihid) {
+ pr_err("VFIO: cannot find ACPI HID for %s\n",
+ vdev->name);
+ return -ENODEV;
}
+ return 0;
+}
+
+static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev)
+{
+ struct device *dev = vdev->device;
+ acpi_handle handle = ACPI_HANDLE(dev);
+ acpi_status acpi_ret;
+ unsigned long long val;
+
+ acpi_ret = acpi_evaluate_integer(handle, "_RST", NULL, &val);
+ if (ACPI_FAILURE(acpi_ret))
+ return -EINVAL;
+
+ return 0;
+}
+
+static int vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
+{
+ struct device *dev = vdev->device;
+ acpi_handle handle = ACPI_HANDLE(dev);
+
+ if (acpi_has_method(handle, "_RST"))
+ return 0;
+
+ return -EINVAL;
+}
+#else
+int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
+ struct device *dev)
+{
+ return -EINVAL;
+}
+
+static int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev)
+{
+ return -EINVAL;
+}
+
+static int vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
+{
+ return -EINVAL;
+}
+#endif
+
+static int vfio_platform_has_reset(struct vfio_platform_device *vdev)
+{
+ if (vdev->acpihid)
+ return vfio_platform_acpi_has_reset(vdev);
+
+ if (vdev->of_reset)
+ return 0;
+
+ return -EINVAL;
+}
+
+static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
+{
+ int rc;
+
+ if (vdev->acpihid)
+ return vfio_platform_acpi_has_reset(vdev);
+
+ vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
+ &vdev->reset_module);
+ if (vdev->of_reset)
+ return 0;
+
+ rc = request_module("vfio-reset:%s", vdev->compat);
+ if (rc)
+ return rc;
+
+ vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
+ &vdev->reset_module);
+ if (vdev->of_reset)
+ return 0;
+
+ return -EINVAL;
}

static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
{
- if (vdev->reset)
+ if (vdev->acpihid)
+ return;
+
+ if (vdev->of_reset)
module_put(vdev->reset_module);
}

@@ -134,6 +226,20 @@ static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
kfree(vdev->regions);
}

+static int vfio_platform_call_reset(struct vfio_platform_device *vdev)
+{
+ if (vdev->of_reset) {
+ dev_info(vdev->device, "reset\n");
+ vdev->of_reset(vdev);
+ return 0;
+ } else if (vdev->acpihid) {
+ return vfio_platform_acpi_call_reset(vdev);
+ }
+
+ dev_warn(vdev->device, "no reset function found!\n");
+ return -EINVAL;
+}
+
static void vfio_platform_release(void *device_data)
{
struct vfio_platform_device *vdev = device_data;
@@ -141,12 +247,7 @@ static void vfio_platform_release(void *device_data)
mutex_lock(&driver_lock);

if (!(--vdev->refcnt)) {
- if (vdev->reset) {
- dev_info(vdev->device, "reset\n");
- vdev->reset(vdev);
- } else {
- dev_warn(vdev->device, "no reset function found!\n");
- }
+ vfio_platform_call_reset(vdev);
vfio_platform_regions_cleanup(vdev);
vfio_platform_irq_cleanup(vdev);
}
@@ -175,12 +276,9 @@ static int vfio_platform_open(void *device_data)
if (ret)
goto err_irq;

- if (vdev->reset) {
- dev_info(vdev->device, "reset\n");
- vdev->reset(vdev);
- } else {
- dev_warn(vdev->device, "no reset function found!\n");
- }
+ ret = vfio_platform_call_reset(vdev);
+ if (ret)
+ goto err_irq;
}

vdev->refcnt++;
@@ -213,7 +311,7 @@ static long vfio_platform_ioctl(void *device_data,
if (info.argsz < minsz)
return -EINVAL;

- if (vdev->reset)
+ if (!vfio_platform_has_reset(vdev))
vdev->flags |= VFIO_DEVICE_FLAGS_RESET;
info.flags = vdev->flags;
info.num_regions = vdev->num_regions;
@@ -312,10 +410,7 @@ static long vfio_platform_ioctl(void *device_data,
return ret;

} else if (cmd == VFIO_DEVICE_RESET) {
- if (vdev->reset)
- return vdev->reset(vdev);
- else
- return -EINVAL;
+ return vfio_platform_call_reset(vdev);
}

return -ENOTTY;
@@ -544,6 +639,21 @@ 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;
+ }
+ return 0;
+}
+
int vfio_platform_probe_common(struct vfio_platform_device *vdev,
struct device *dev)
{
@@ -553,14 +663,14 @@ 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);

- vdev->device = dev;
+ if (ret)
+ return ret;

+ vdev->device = dev;
group = iommu_group_get(dev);
if (!group) {
pr_err("VFIO: No IOMMU group for device %s\n", vdev->name);
@@ -611,7 +721,7 @@ void vfio_platform_unregister_reset(const char *compat,

mutex_lock(&driver_lock);
list_for_each_entry_safe(iter, temp, &reset_list, link) {
- if (!strcmp(iter->compat, compat) && (iter->reset == fn)) {
+ if (!strcmp(iter->compat, compat) && (iter->of_reset == fn)) {
list_del(&iter->link);
break;
}
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 42816dd..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;

@@ -71,7 +72,7 @@ struct vfio_platform_device {
struct resource*
(*get_resource)(struct vfio_platform_device *vdev, int i);
int (*get_irq)(struct vfio_platform_device *vdev, int i);
- int (*reset)(struct vfio_platform_device *vdev);
+ int (*of_reset)(struct vfio_platform_device *vdev);
};

typedef int (*vfio_platform_reset_fn_t)(struct vfio_platform_device *vdev);
@@ -80,7 +81,7 @@ struct vfio_platform_reset_node {
struct list_head link;
char *compat;
struct module *owner;
- vfio_platform_reset_fn_t reset;
+ vfio_platform_reset_fn_t of_reset;
};

extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
@@ -103,7 +104,7 @@ extern void vfio_platform_unregister_reset(const char *compat,
static struct vfio_platform_reset_node __reset ## _node = { \
.owner = THIS_MODULE, \
.compat = __compat, \
- .reset = __reset, \
+ .of_reset = __reset, \
}; \
__vfio_platform_register_reset(&__reset ## _node)

--
1.8.2.1