[drm/amdgpu]: user queue doorbell allocation for IP reqs

Saleemkhan Jamadar sjamadar at amd.com
Fri Jan 3 06:34:35 UTC 2025


Hi Shashank,

Replied inline [Saleem]


Regards,

Salem

On 02/01/25 18:58, Sharma, Shashank wrote:
> + (amd-gfx)
>
> On 01/01/2025 07:03, Saleemkhan Jamadar wrote:
>> #resending  patch
>>
>>  From 79cd62f882197505dbf9c489ead2b0bcab98209f Mon Sep 17 00:00:00 2001
>> From: Saleemkhan Jamadar <saleemkhan.jamadar at amd.com>
>> Date: Wed, 18 Dec 2024 19:30:22 +0530
>> Subject: [PATCH] drm/amdgpu: user queue doorbell allocation for IP reqs
>>
>> Currenlty doorbell allocation handles only 64 bit db size.
>>
>> In case of VCN we need to allocated AGDB and per instance
>> doorbell.VCN/UMSCH doorbell size is 32 bit and offset
>> calculated is from specific range from the allocated page.
>>
>> With these changes individual IP can provide specific reqs
>> for db allocation.
>>
>> Signed-off-by: Saleemkhan Jamadar <saleemkhan.jamadar at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c | 41 ++++++++++++++-----
>>   .../gpu/drm/amd/include/amdgpu_userqueue.h    | 12 ++++++
>>   2 files changed, 42 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
>> index cba51bdf2e2c..4fff15e0d838 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
>> @@ -163,18 +163,17 @@ void amdgpu_userqueue_destroy_object(struct 
>> amdgpu_userq_mgr *uq_mgr,
>>       amdgpu_bo_unref(&userq_obj->obj);
>>   }
>>   -static uint64_t
>> +uint64_t
>>   amdgpu_userqueue_get_doorbell_index(struct amdgpu_userq_mgr *uq_mgr,
>> -                     struct amdgpu_usermode_queue *queue,
>> -                     struct drm_file *filp,
>> -                     uint32_t doorbell_offset)
>> +                     struct amdgpu_db_info *db_info,
>> +                     struct drm_file *filp)
>>   {
>>       uint64_t index;
>>       struct drm_gem_object *gobj;
>> -    struct amdgpu_userq_obj *db_obj = &queue->db_obj;
>> -    int r;
>> +    struct amdgpu_userq_obj *db_obj = db_info->db_obj;
>> +    int r, db_size;
>>   -    gobj = drm_gem_object_lookup(filp, queue->doorbell_handle);
>> +    gobj = drm_gem_object_lookup(filp, db_info->doorbell_handle);
>>       if (gobj == NULL) {
>>           DRM_ERROR("Can't find GEM object for doorbell\n");
>>           return -EINVAL;
>> @@ -196,8 +195,23 @@ amdgpu_userqueue_get_doorbell_index(struct 
>> amdgpu_userq_mgr *uq_mgr,
>>           goto unpin_bo;
>>       }
>>   +    switch (db_info->queue_type) {
>> +    case AMDGPU_HW_IP_GFX:
>> +    case AMDGPU_HW_IP_COMPUTE:
>> +    case AMDGPU_HW_IP_DMA:
>> +        db_size = sizeof(u64);
>> +        break;
>> +    case AMDGPU_HW_IP_VCN_ENC:
>> +        db_size = sizeof(u32);
>> +        db_info->doorbell_offset += AMDGPU_NAVI10_DOORBELL64_VCN0_1 
>> << 1;
>> +        break;
>> +    default:
>> +        DRM_WARN("User queues not supported for IP (%d )\n", 
>> db_info->queue_type);
>> +        return -EINVAL;
>> +    }
>> +
>>       index = amdgpu_doorbell_index_on_bar(uq_mgr->adev, db_obj->obj,
>> -                         doorbell_offset, sizeof(u64));
>> +                         db_info->doorbell_offset, db_size);
>>       DRM_DEBUG_DRIVER("[Usermode queues] doorbell index=%lld\n", 
>> index);
>>       amdgpu_bo_unreserve(db_obj->obj);
>>       return index;
>> @@ -242,6 +256,7 @@ amdgpu_userqueue_create(struct drm_file *filp, 
>> union drm_amdgpu_userq *args)
>>       struct amdgpu_device *adev = uq_mgr->adev;
>>       const struct amdgpu_userq_funcs *uq_funcs;
>>       struct amdgpu_usermode_queue *queue;
>> +    struct amdgpu_db_info db_info;
>>       uint64_t index;
>>       int qid, r = 0;
>>   @@ -269,19 +284,23 @@ amdgpu_userqueue_create(struct drm_file 
>> *filp, union drm_amdgpu_userq *args)
>>           goto unlock;
>>       }
>>       queue->doorbell_handle = args->in.doorbell_handle;
>> -    queue->doorbell_index = args->in.doorbell_offset;
> Nack, this is going to break mapping/unmapping for GFX UQ. Nothing 
> should be removed from the queue structure, as all of it is accounted 
> for.
[Saleem]:This assignment is not used anywhere, moreover it gets 
overwritten with mapped doorbell index below.
>>       queue->queue_type = args->in.ip_type;
>>       queue->vm = &fpriv->vm;
>>   +    db_info.queue_type = queue->queue_type;
>> +    db_info.doorbell_handle = queue->doorbell_handle;
>> +    db_info.db_obj = &queue->db_obj;
>> +    db_info.doorbell_offset = args->in.doorbell_offset;
>> +
> I can see that all the information you are adding in struct db_info is 
> coming from queue only, then why to add a new structure here at all ? 
> Instead, you can just do this in function
> [Saleem]: In previous impl you can see that db_obj is fetched form 
> queue structure. In case of vcn we have mulpitle doorbell to be 
> allocated, to accomodate this and to avoid the another level of check 
> to identify which doorbell is being allocated this db_info (structure 
> used locally) helps. db_info shares data for which allocation needs to 
> done.
>
> amdgpu_userqueue_get_doorbell_index():
>
> db_size = sizeof(u62);
>
> switch(queue->queue_type) {
> case VCN:
>     queue->doorbell_offset += AMDGPU_NAVI10_DOORBELL64_VCN0_1 << 1;
>     db_size = sizeof(u32);
>     break;
> }
> [Saleem]: This change I can make.
> <same doorbell offset calculation as usual>
>
> - Shashank
>
>>       /* Convert relative doorbell offset into absolute doorbell 
>> index */
>> -    index = amdgpu_userqueue_get_doorbell_index(uq_mgr, queue, filp, 
>> args->in.doorbell_offset);
>> +    index = amdgpu_userqueue_get_doorbell_index(uq_mgr, &db_info, 
>> filp);
>>       if (index == (uint64_t)-EINVAL) {
>>           DRM_ERROR("Failed to get doorbell for queue\n");
>>           kfree(queue);
>>           goto unlock;
>>       }
>> -    queue->doorbell_index = index;
>>   +    queue->doorbell_index = index;
>>       xa_init_flags(&queue->fence_drv_xa, XA_FLAGS_ALLOC);
>>       r = amdgpu_userq_fence_driver_alloc(adev, queue);
>>       if (r) {
>> diff --git a/drivers/gpu/drm/amd/include/amdgpu_userqueue.h 
>> b/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
>> index 2bf28f3454cb..3d54601c6a24 100644
>> --- a/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
>> +++ b/drivers/gpu/drm/amd/include/amdgpu_userqueue.h
>> @@ -39,6 +39,13 @@ struct amdgpu_userq_obj {
>>       struct amdgpu_bo *obj;
>>   };
>>   +struct amdgpu_db_info {
>> +    uint64_t doorbell_handle;
>> +    uint32_t queue_type;
>> +    uint32_t doorbell_offset;
>> +    struct amdgpu_userq_obj    *db_obj;
>> +};
>> +
>>   struct amdgpu_usermode_queue {
>>       int            queue_type;
>>       uint8_t            queue_active;
>> @@ -93,4 +100,9 @@ void amdgpu_userqueue_destroy_object(struct 
>> amdgpu_userq_mgr *uq_mgr,
>>   void amdgpu_userqueue_suspend(struct amdgpu_userq_mgr *uq_mgr);
>>     int amdgpu_userqueue_active(struct amdgpu_userq_mgr *uq_mgr);
>> +
>> +uint64_t amdgpu_userqueue_get_doorbell_index(struct amdgpu_userq_mgr 
>> *uq_mgr,
>> +                     struct amdgpu_db_info *db_info,
>> +                     struct drm_file *filp);
>> +
>>   #endif


More information about the amd-gfx mailing list