drm/amdkfd: Remove sync_with_hw() from amdkfd

This patch completely removes the sync_with_hw() because it was broken and
actually there is no point of using it.

This function was used to:

- Make sure that the submitted packet to the HIQ (which is a kernel queue) was
read by the CP. However, it was discovered that the method this function used
to do that (checking wptr == rptr) is not consistent with how the actual CP
firmware works in all cases.

- Make sure that the queue is empty before issuing the next packet. To achieve
that, the function blocked amdkfd from continuing until the recently
submitted packet was consumed. However, the acquire_packet_buffer() already
checks if there is enough room for a new packet so calling sync_with_hw() is
redundant.

Signed-off-by: Oded Gabbay <[e-mail]>
Acked-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdkfd/kfd_kernel_queue.c

···
 				kq->pending_wptr);
 }
 
-static int sync_with_hw(struct kernel_queue *kq, unsigned long timeout_ms)
-{
-	unsigned long org_timeout_ms;
-
-	BUG_ON(!kq);
-
-	org_timeout_ms = timeout_ms;
-	timeout_ms += jiffies * 1000 / HZ;
-	while (*kq->wptr_kernel != *kq->rptr_kernel) {
-		if (time_after(jiffies * 1000 / HZ, timeout_ms)) {
-			pr_err("kfd: kernel_queue %s timeout expired %lu\n",
-				__func__, org_timeout_ms);
-			pr_err("kfd: wptr: %d rptr: %d\n",
-				*kq->wptr_kernel, *kq->rptr_kernel);
-			return -ETIME;
-		}
-		schedule();
-	}
-
-	return 0;
-}
-
 static void rollback_packet(struct kernel_queue *kq)
 {
 	BUG_ON(!kq);
···
 	kq->ops.uninitialize = uninitialize;
 	kq->ops.acquire_packet_buffer = acquire_packet_buffer;
 	kq->ops.submit_packet = submit_packet;
-	kq->ops.sync_with_hw = sync_with_hw;
 	kq->ops.rollback_packet = rollback_packet;
 
 	switch (dev->device_info->asic_family) {
···
 	for (i = 0; i < 5; i++)
 		buffer[i] = kq->nop_packet;
 	kq->ops.submit_packet(kq);
-	kq->ops.sync_with_hw(kq, 1000);
 
 	pr_err("kfd: ending kernel queue test\n");
 }

drivers/gpu/drm/amd/amdkfd/kfd_kernel_queue.h

···
 					unsigned int **buffer_ptr);
 
 	void	(*submit_packet)(struct kernel_queue *kq);
-	int	(*sync_with_hw)(struct kernel_queue *kq,
-				unsigned long timeout_ms);
 	void	(*rollback_packet)(struct kernel_queue *kq);
 };
 

drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c

···
 	packet->queue_mask_hi = upper_32_bits(res->queue_mask);
 
 	pm->priv_queue->ops.submit_packet(pm->priv_queue);
-	pm->priv_queue->ops.sync_with_hw(pm->priv_queue, KFD_HIQ_TIMEOUT);
 
 	mutex_unlock(&pm->lock);
 
···
 		goto fail_create_runlist;
 
 	pm->priv_queue->ops.submit_packet(pm->priv_queue);
-	pm->priv_queue->ops.sync_with_hw(pm->priv_queue, KFD_HIQ_TIMEOUT);
 
 	mutex_unlock(&pm->lock);
 
···
 	packet->data_lo = lower_32_bits((uint64_t)fence_value);
 
 	pm->priv_queue->ops.submit_packet(pm->priv_queue);
-	pm->priv_queue->ops.sync_with_hw(pm->priv_queue, KFD_HIQ_TIMEOUT);
 	mutex_unlock(&pm->lock);
 
 	return 0;
···
 	};
 
 	pm->priv_queue->ops.submit_packet(pm->priv_queue);
-	pm->priv_queue->ops.sync_with_hw(pm->priv_queue, KFD_HIQ_TIMEOUT);
 
 	mutex_unlock(&pm->lock);
 	return 0;