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

Sinan Kaya
2016-05-09T19:45:13Z

On 5/9/2016 11:47 AM, Eric Auger wrote:
> Hi Sinan,
> On 05/01/2016 11:07 PM, Sinan Kaya 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.
>>
>> 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;
> Can't you directly return acpi_has_method(handle, "_RST"), hence return
> a boolean?

Makes sense. I'll do that on the next post.

>> +
>> + 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)
>> +{
> return a boolean?

OK

>> + 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 vdev->of_reset(vdev) to align with acpi reset behavior.

OK. I didn't realize it was returning a value.

>> + return 0;
>> + } else if (vdev->acpihid) {
>> + return vfio_platform_acpi_call_reset(vdev);
> I think it would make sense to have the same dev_info traces for dt and
> acpi.
>> + }
>> +
>> + 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;
> This change should be in next patch since if you fail finding a reset
> function, you clean things up, mandating a reset function to exist.
>
> Also in case the reset function fails you change the behavior which is
> not detailed in the commit msg.

I admitted this on another patch. Yes, I'll fix this.

>> }
>>
>> 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);
> Here you also change the behavior: before, in case the dt reset failed
> we returned an error. Now we return 0.

Yes, I'll fix it.
>
> To me this patch would deserve to be split into 2 parts: ACPI probing
> without reset and then ACPI reset. In case you change the behavior of
> existing dt reset, please put that in a separate patch.

Sure, I'll move vfio_platform_probe_common changes to a seperate patch.
I'll try to break it as much as I can before the post.

>
> Best Regards
>
> Eric
>> }
>>
>> 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)
>>
>>
>

--
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project