On 2023-03-30 10:49, Christian König wrote:
> Am 30.03.23 um 16:40 schrieb Shashank Sharma:
>>
>> On 30/03/2023 16:24, Luben Tuikov wrote:
>>> On 2023-03-29 11:47, Shashank Sharma wrote:
>>>> From: Shashank Sharma <contactshashanksharma@xxxxxxxxx>
>>>>
>>>> This patch:
>>>> - creates a doorbell page for graphics driver usages.
>>>> - removes the adev->doorbell.ptr variable, replaces it with
>>>> kernel-doorbell-bo's cpu address.
>>>>
>>>> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
>>>> Cc: Christian Koenig <christian.koenig@xxxxxxx>
>>>> Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxx>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h | 16 ++++++-
>>>> .../gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c | 44
>>>> +++++++++++++++----
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 7 +++
>>>> 3 files changed, 57 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
>>>> index 6581b78fe438..10a9bb10e974 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
>>>> @@ -49,10 +49,13 @@ struct amdgpu_doorbell {
>>>> /* doorbell mmio */
>>>> resource_size_t base;
>>>> resource_size_t size;
>>>> - u32 __iomem *ptr;
>>>> + u32 __iomem *ptr;
>>>> /* Number of doorbells reserved for amdgpu kernel driver */
>>>> u32 num_kernel_doorbells;
>>>> +
>>>> + /* For kernel doorbell pages */
>>>> + struct amdgpu_doorbell_obj kernel_doorbells;
>>>> };
>>> Here's an example where it could be confusing what the difference is
>>> between "struct amdgpu_doorbell" and "struct amdgpu_doobell_obj".
>>> As the comment to the struct doorbell_obj declarations says
>>> in patch 7,
>>>> +/* Structure to hold doorbell pages from PCI doorbell BAR */
>>>> +struct amdgpu_doorbell_obj {
>>
>> What is the confusion ? This is the object which is holding doorbell
>> page. There could be 2 type of
>>
>> doorbell pages, kernel and process, this is a kernel one.
>>
>>> Perhaps we should call it "struct amdgpu_doorbell_bo", since
>>> it does contain amdgpu_bo's, which are doorbell's bos.
>>
>> This is not a buffer object (memory), this is doorbell object, so
>> calling it bo would be wrong.
>
> I think what Luben means is that in object orient programming this here
> would be the class. The object is then the actual instantiation of that.
Yes, absolutely exactly what Christian said.
Regards,
Luben
>
> But I have some real doubts that this is the right approach in the first
> place.
>
> Regards,
> Christian.
>
>>
>> - Shashank
>>
>>>
>>> Regards,
>>> Luben
>>>
>>>> /* Reserved doorbells for amdgpu (including multimedia).
>>>> @@ -369,6 +372,17 @@ void amdgpu_doorbell_free_page(struct
>>>> amdgpu_device *adev,
>>>> int amdgpu_doorbell_alloc_page(struct amdgpu_device *adev,
>>>> struct amdgpu_doorbell_obj *db_obj);
>>>> +/**
>>>> + * amdgpu_doorbell_create_kernel_doorbells - Create kernel
>>>> doorbells for graphics
>>>> + *
>>>> + * @adev: amdgpu_device pointer
>>>> + *
>>>> + * Creates doorbells for graphics driver
>>>> + *
>>>> + * returns 0 on success, error otherwise.
>>>> + */
>>>> +int amdgpu_doorbell_create_kernel_doorbells(struct amdgpu_device
>>>> *adev);
>>>> +
>>>> #define RDOORBELL32(index) amdgpu_mm_rdoorbell(adev, (index))
>>>> #define WDOORBELL32(index, v) amdgpu_mm_wdoorbell(adev, (index), (v))
>>>> #define RDOORBELL64(index) amdgpu_mm_rdoorbell64(adev, (index))
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
>>>> index 8be15b82b545..b46fe8b1378d 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
>>>> @@ -160,6 +160,38 @@ int amdgpu_doorbell_alloc_page(struct
>>>> amdgpu_device *adev,
>>>> return 0;
>>>> }
>>>> +/**
>>>> + * amdgpu_doorbell_create_kernel_doorbells - Create kernel
>>>> doorbells for graphics
>>>> + *
>>>> + * @adev: amdgpu_device pointer
>>>> + *
>>>> + * Creates doorbells for graphics driver
>>>> + *
>>>> + * returns 0 on success, error otherwise.
>>>> + */
>>>> +int amdgpu_doorbell_create_kernel_doorbells(struct amdgpu_device
>>>> *adev)
>>>> +{
>>>> + int r;
>>>> + struct amdgpu_doorbell_obj *kernel_doorbells =
>>>> &adev->doorbell.kernel_doorbells;
>>>> +
>>>> + kernel_doorbells->doorbell_bitmap =
>>>> bitmap_zalloc(adev->doorbell.num_kernel_doorbells,
>>>> + GFP_KERNEL);
>>>> + if (!kernel_doorbells->doorbell_bitmap) {
>>>> + DRM_ERROR("Failed to create kernel doorbell bitmap\n");
>>>> + return -ENOMEM;
>>>> + }
>>>> +
>>>> + kernel_doorbells->size = adev->doorbell.num_kernel_doorbells *
>>>> sizeof(u32);
>>>> + r = amdgpu_doorbell_alloc_page(adev, kernel_doorbells);
>>>> + if (r) {
>>>> + bitmap_free(kernel_doorbells->doorbell_bitmap);
>>>> + DRM_ERROR("Failed to allocate kernel doorbells, err=%d\n", r);
>>>> + return r;
>>>> + }
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> /*
>>>> * GPU doorbell aperture helpers function.
>>>> */
>>>> @@ -179,7 +211,6 @@ int amdgpu_device_doorbell_init(struct
>>>> amdgpu_device *adev)
>>>> adev->doorbell.base = 0;
>>>> adev->doorbell.size = 0;
>>>> adev->doorbell.num_kernel_doorbells = 0;
>>>> - adev->doorbell.ptr = NULL;
>>>> return 0;
>>>> }
>>>> @@ -208,12 +239,7 @@ int amdgpu_device_doorbell_init(struct
>>>> amdgpu_device *adev)
>>>> if (adev->asic_type >= CHIP_VEGA10)
>>>> adev->doorbell.num_kernel_doorbells += 0x400;
>>>> - adev->doorbell.ptr = ioremap(adev->doorbell.base,
>>>> - adev->doorbell.num_kernel_doorbells *
>>>> - sizeof(u32));
>>>> - if (adev->doorbell.ptr == NULL)
>>>> - return -ENOMEM;
>>>> -
>>>> + adev->doorbell.ptr = ioremap(adev->doorbell.base,
>>>> adev->doorbell.size);
>>>> return 0;
>>>> }
>>>> @@ -226,6 +252,6 @@ int amdgpu_device_doorbell_init(struct
>>>> amdgpu_device *adev)
>>>> */
>>>> void amdgpu_device_doorbell_fini(struct amdgpu_device *adev)
>>>> {
>>>> - iounmap(adev->doorbell.ptr);
>>>> - adev->doorbell.ptr = NULL;
>>>> + bitmap_free(adev->doorbell.kernel_doorbells.doorbell_bitmap);
>>>> + amdgpu_doorbell_free_page(adev, &adev->doorbell.kernel_doorbells);
>>>> }
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>> index 203d77a20507..75c6852845c4 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>>>> @@ -1866,6 +1866,13 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
>>>> return r;
>>>> }
>>>> + /* Create a boorbell page for kernel usages */
>>>> + r = amdgpu_doorbell_create_kernel_doorbells(adev);
>>>> + if (r) {
>>>> + DRM_ERROR("Failed to initialize kernel doorbells. \n");
>>>> + return r;
>>>> + }
>>>> +
>>>> /* Initialize preemptible memory pool */
>>>> r = amdgpu_preempt_mgr_init(adev);
>>>> if (r) {
>
