[PATCH 07/16] drm/amdgpu: add helper to create doorbell pages

[Luben Tuikov]

On 2023-03-30 10:28, Alex Deucher wrote:
> On Wed, Mar 29, 2023 at 11:48 AM Shashank Sharma
> <shashank.sharma at amd.com> wrote:
>>
>> From: Shashank Sharma <contactshashanksharma at gmail.com>
>>
>> This patch adds helper functions to create and free doorbell
>> pages for kernel objects.
> 
> I think we can probably drop this patch.  I think it would be simpler
> to just use standard amdgpu_bos to represent them and then maybe a
> helper function to calculate the BAR offset from a doorbell bo object.

I agree.

Regards,
Luben

> 
> Alex
> 
>>
>> Cc: Alex Deucher <alexander.deucher at amd.com>
>> Cc: Christian Koenig <christian.koenig at amd.com>
>> Signed-off-by: Shashank Sharma <shashank.sharma at amd.com>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h  | 41 ++++++++++++++++
>>  .../gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c  | 49 +++++++++++++++++++
>>  2 files changed, 90 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
>> index f9c3b77bf65d..6581b78fe438 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
>> @@ -27,6 +27,24 @@
>>  /*
>>   * GPU doorbell structures, functions & helpers
>>   */
>> +
>> +/* Structure to hold doorbell pages from PCI doorbell BAR */
>> +struct amdgpu_doorbell_obj {
>> +       struct amdgpu_bo *bo;
>> +       uint64_t gpu_addr;
>> +       uint32_t *cpu_addr;
>> +       uint32_t size;
>> +
>> +       /* First index in this object */
>> +       uint32_t start;
>> +
>> +       /* Last index in this object */
>> +       uint32_t end;
>> +
>> +       /* bitmap for dynamic doorbell allocation from this object */
>> +       unsigned long *doorbell_bitmap;
>> +};
>> +
>>  struct amdgpu_doorbell {
>>         /* doorbell mmio */
>>         resource_size_t         base;
>> @@ -328,6 +346,29 @@ int amdgpu_device_doorbell_init(struct amdgpu_device *adev);
>>   */
>>  void amdgpu_device_doorbell_fini(struct amdgpu_device *adev);
>>
>> +/**
>> + * amdgpu_doorbell_free_page - Free a doorbell page
>> + *
>> + * @adev: amdgpu_device pointer
>> + *
>> + * @db_age: previously allocated doobell page details
>> + *
>> + */
>> +void amdgpu_doorbell_free_page(struct amdgpu_device *adev,
>> +                               struct amdgpu_doorbell_obj *db_obj);
>> +
>> +/**
>> + * amdgpu_doorbell_alloc_page - create a page from doorbell pool
>> + *
>> + * @adev: amdgpu_device pointer
>> + *
>> + * @db_age: doobell page structure to fill details with
>> + *
>> + * returns 0 on success, else error number
>> + */
>> +int amdgpu_doorbell_alloc_page(struct amdgpu_device *adev,
>> +                               struct amdgpu_doorbell_obj *db_obj);
>> +
>>  #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 1aea92363fd3..8be15b82b545 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
>> @@ -111,6 +111,55 @@ void amdgpu_mm_wdoorbell64(struct amdgpu_device *adev, u32 index, u64 v)
>>         }
>>  }
>>
>> +/**
>> + * amdgpu_doorbell_free_page - Free a doorbell page
>> + *
>> + * @adev: amdgpu_device pointer
>> + *
>> + * @db_age: previously allocated doobell page details
>> + *
>> + */
>> +void amdgpu_doorbell_free_page(struct amdgpu_device *adev,
>> +                                       struct amdgpu_doorbell_obj *db_obj)
>> +{
>> +       amdgpu_bo_free_kernel(&db_obj->bo,
>> +                             &db_obj->gpu_addr,
>> +                             (void **)&db_obj->cpu_addr);
>> +
>> +}
>> +
>> +/**
>> + * amdgpu_doorbell_alloc_page - create a page from doorbell pool
>> + *
>> + * @adev: amdgpu_device pointer
>> + *
>> + * @db_age: doobell page structure to fill details with
>> + *
>> + * returns 0 on success, else error number
>> + */
>> +int amdgpu_doorbell_alloc_page(struct amdgpu_device *adev,
>> +                               struct amdgpu_doorbell_obj *db_obj)
>> +{
>> +       int r;
>> +
>> +       db_obj->size = ALIGN(db_obj->size, PAGE_SIZE);
>> +
>> +       r = amdgpu_bo_create_kernel(adev,
>> +                                   db_obj->size,
>> +                                   PAGE_SIZE,
>> +                                   AMDGPU_GEM_DOMAIN_DOORBELL,
>> +                                   &db_obj->bo,
>> +                                   &db_obj->gpu_addr,
>> +                                   (void **)&db_obj->cpu_addr);
>> +
>> +       if (r) {
>> +               DRM_ERROR("Failed to create doorbell BO, err=%d\n", r);
>> +               return r;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>>  /*
>>   * GPU doorbell aperture helpers function.
>>   */
>> --
>> 2.40.0
>>