[PATCH V3 1/3] vfio, platform: add support for ACPI while detecting the reset driver

From: Sinan Kaya
Date: Mon Mar 28 2016 - 09:35:57 EST

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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.
The change allows a driver to register with DT compatible string or ACPI
HID and then match the object with one of these conditions.

Rules for loading the reset driver are as follow:
- ACPI HID needs match for ACPI systems
- DT compat needs to match for OF systems

Tested-by: Eric Auger <eric.auger@xxxxxxxxxx> (device tree only)
Tested-by: Shanker Donthineni <shankerd@xxxxxxxxxxxxxx> (ACPI only)
Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
---
.../vfio/platform/reset/vfio_platform_amdxgbe.c | 4 +-
.../platform/reset/vfio_platform_calxedaxgmac.c | 4 +-
drivers/vfio/platform/vfio_platform_common.c | 107 +++++++++++++++++----
drivers/vfio/platform/vfio_platform_private.h | 43 +++++----
4 files changed, 120 insertions(+), 38 deletions(-)

diff --git a/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c b/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
index d4030d0..6d87442 100644
--- a/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
+++ b/drivers/vfio/platform/reset/vfio_platform_amdxgbe.c
@@ -119,7 +119,9 @@ int vfio_platform_amdxgbe_reset(struct vfio_platform_device *vdev)
return 0;
}

-module_vfio_reset_handler("amd,xgbe-seattle-v1a", vfio_platform_amdxgbe_reset);
+module_vfio_reset_handler("amd,xgbe-seattle-v1a", NULL,
+ vfio_platform_amdxgbe_reset);
+MODULE_ALIAS_VFIO_PLATFORM_RESET("amd,xgbe-seattle-v1a");

MODULE_VERSION("0.1");
MODULE_LICENSE("GPL v2");
diff --git a/drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c b/drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c
index e3d3d94..952dd55 100644
--- a/drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c
+++ b/drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c
@@ -77,7 +77,9 @@ int vfio_platform_calxedaxgmac_reset(struct vfio_platform_device *vdev)
return 0;
}

-module_vfio_reset_handler("calxeda,hb-xgmac", vfio_platform_calxedaxgmac_reset);
+module_vfio_reset_handler("calxeda,hb-xgmac", NULL,
+ vfio_platform_calxedaxgmac_reset);
+MODULE_ALIAS_VFIO_PLATFORM_RESET("calxeda,hb-xgmac");

MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index e65b142..c28883a 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>
@@ -31,14 +32,22 @@ static LIST_HEAD(reset_list);
static DEFINE_MUTEX(driver_lock);

static vfio_platform_reset_fn_t vfio_platform_lookup_reset(const char *compat,
- struct module **module)
+ const char *acpihid, struct module **module)
{
struct vfio_platform_reset_node *iter;
vfio_platform_reset_fn_t reset_fn = NULL;

mutex_lock(&driver_lock);
list_for_each_entry(iter, &reset_list, link) {
- if (!strcmp(iter->compat, compat) &&
+ if (acpihid && iter->acpihid &&
+ !strcmp(iter->acpihid, acpihid) &&
+ try_module_get(iter->owner)) {
+ *module = iter->owner;
+ reset_fn = iter->reset;
+ break;
+ }
+ if (compat && iter->compat &&
+ !strcmp(iter->compat, compat) &&
try_module_get(iter->owner)) {
*module = iter->owner;
reset_fn = iter->reset;
@@ -49,15 +58,30 @@ 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)
+static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
{
- 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);
- }
+ int rc = -ENODEV;
+
+ vdev->reset = vfio_platform_lookup_reset(vdev->compat, vdev->acpihid,
+ &vdev->reset_module);
+ if (vdev->reset)
+ return 0;
+
+ if (vdev->acpihid)
+ rc = request_module("vfio-reset:%s", vdev->acpihid);
+
+ if (rc && vdev->compat)
+ rc = request_module("vfio-reset:%s", vdev->compat);
+
+ if (rc)
+ return rc;
+
+ vdev->reset = vfio_platform_lookup_reset(vdev->compat, vdev->acpihid,
+ &vdev->reset_module);
+ if (vdev->reset)
+ return 0;
+
+ return -ENODEV;
}

static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
@@ -544,6 +568,46 @@ static const struct vfio_device_ops vfio_platform_ops = {
.mmap = vfio_platform_mmap,
};

+#ifdef CONFIG_ACPI
+int vfio_platform_probe_acpi(struct vfio_platform_device *vdev,
+ struct device *dev)
+{
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+
+ 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;
+}
+#else
+int vfio_platform_probe_acpi(struct vfio_platform_device *vdev,
+ struct device *dev)
+{
+ return -EINVAL;
+}
+#endif
+
+int vfio_platform_probe_of(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 +617,14 @@ 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_probe_acpi(vdev, dev);
+ if (ret)
+ ret = vfio_platform_probe_of(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);
@@ -574,7 +638,6 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
}

vfio_platform_get_reset(vdev);
-
mutex_init(&vdev->igate);

return 0;
@@ -605,13 +668,21 @@ void __vfio_platform_register_reset(struct vfio_platform_reset_node *node)
EXPORT_SYMBOL_GPL(__vfio_platform_register_reset);

void vfio_platform_unregister_reset(const char *compat,
+ const char *acpihid,
vfio_platform_reset_fn_t fn)
{
struct vfio_platform_reset_node *iter, *temp;

mutex_lock(&driver_lock);
list_for_each_entry_safe(iter, temp, &reset_list, link) {
- if (!strcmp(iter->compat, compat) && (iter->reset == fn)) {
+ if (acpihid && iter->acpihid &&
+ !strcmp(iter->acpihid, acpihid) && (iter->reset == fn)) {
+ list_del(&iter->link);
+ break;
+ }
+
+ if (compat && iter->compat &&
+ !strcmp(iter->compat, compat) && (iter->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..1b95adf 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;

@@ -79,6 +80,7 @@ typedef int (*vfio_platform_reset_fn_t)(struct vfio_platform_device *vdev);
struct vfio_platform_reset_node {
struct list_head link;
char *compat;
+ char *acpihid;
struct module *owner;
vfio_platform_reset_fn_t reset;
};
@@ -98,27 +100,32 @@ extern int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,

extern void __vfio_platform_register_reset(struct vfio_platform_reset_node *n);
extern void vfio_platform_unregister_reset(const char *compat,
+ const char *acpihid,
vfio_platform_reset_fn_t fn);
-#define vfio_platform_register_reset(__compat, __reset) \
-static struct vfio_platform_reset_node __reset ## _node = { \
- .owner = THIS_MODULE, \
- .compat = __compat, \
- .reset = __reset, \
-}; \
+
+#define vfio_platform_register_reset(__compat, __acpihid, __reset) \
+static struct vfio_platform_reset_node __reset ## _node = { \
+ .owner = THIS_MODULE, \
+ .compat = __compat, \
+ .acpihid = __acpihid, \
+ .reset = __reset, \
+}; \
__vfio_platform_register_reset(&__reset ## _node)

-#define module_vfio_reset_handler(compat, reset) \
-MODULE_ALIAS("vfio-reset:" compat); \
-static int __init reset ## _module_init(void) \
-{ \
- vfio_platform_register_reset(compat, reset); \
- return 0; \
-}; \
-static void __exit reset ## _module_exit(void) \
-{ \
- vfio_platform_unregister_reset(compat, reset); \
-}; \
-module_init(reset ## _module_init); \
+#define MODULE_ALIAS_VFIO_PLATFORM_RESET(name) \
+ MODULE_ALIAS("vfio-reset:" name)
+
+#define module_vfio_reset_handler(compat, acpihid, reset) \
+static int __init reset ## _module_init(void) \
+{ \
+ vfio_platform_register_reset(compat, acpihid, reset); \
+ return 0; \
+}; \
+static void __exit reset ## _module_exit(void) \
+{ \
+ vfio_platform_unregister_reset(compat, acpihid, reset); \
+}; \
+module_init(reset ## _module_init); \
module_exit(reset ## _module_exit)

#endif /* VFIO_PLATFORM_PRIVATE_H */
--
1.8.2.1

Next message: Sinan Kaya: "[PATCH V3 2/3] vfio, platform: make reset driver a requirement by default"
Previous message: Dietmar Eggemann: "Re: [PATCH 1/2] sched/fair: move cpufreq hook to update_cfs_rq_load_avg()"
Next in thread: Arnd Bergmann: "Re: [PATCH V3 1/3] vfio, platform: add support for ACPI while detecting the reset driver"
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