[PATCH 09/16] drm/amdgpu: create kernel doorbell page
Shashank Sharma
shashank.sharma at amd.com
Thu Mar 30 14:40:53 UTC 2023
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.
- 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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