[PATCH 09/16] drm/amdgpu: create kernel doorbell page
Christian König
christian.koenig at amd.com
Thu Mar 30 14:49:18 UTC 2023
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 at gmail.com>
>>>
>>> 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 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 | 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.
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) {
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