drm/amdkfd: Use order_base_2 to get log2 of buffes sizes

Replace (ffs(size) - 1) with order_base_2(size) as a more straight
forward way to get log2 of buffer sizes.
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>

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

@@ -183,7 +183,7 @@ static int update_mqd(struct mqd_manager *mm, void *mqd,
 	 * Calculating queue size which is log base 2 of actual queue size -1
 	 * dwords and another -1 for ffs
 	 */
-	m->cp_hqd_pq_control |= ffs(q->queue_size / 4) - 1 - 1;
+	m->cp_hqd_pq_control |= order_base_2(q->queue_size / 4) - 1;
 	m->cp_hqd_pq_base_lo = lower_32_bits((uint64_t)q->queue_address >> 8);
 	m->cp_hqd_pq_base_hi = upper_32_bits((uint64_t)q->queue_address >> 8);
 	m->cp_hqd_pq_rptr_report_addr_lo = lower_32_bits((uint64_t)q->read_ptr);
@@ -208,7 +208,7 @@ static int update_mqd_sdma(struct mqd_manager *mm, void *mqd,
 	struct cik_sdma_rlc_registers *m;
 
 	m = get_sdma_mqd(mqd);
-	m->sdma_rlc_rb_cntl = (ffs(q->queue_size / 4) - 1)
+	m->sdma_rlc_rb_cntl = order_base_2(q->queue_size / 4)
 			<< SDMA0_RLC0_RB_CNTL__RB_SIZE__SHIFT |
 			q->vmid << SDMA0_RLC0_RB_CNTL__RB_VMID__SHIFT |
 			1 << SDMA0_RLC0_RB_CNTL__RPTR_WRITEBACK_ENABLE__SHIFT |
@@ -349,7 +349,7 @@ static int update_mqd_hiq(struct mqd_manager *mm, void *mqd,
 	 * Calculating queue size which is log base 2 of actual queue
 	 * size -1 dwords
 	 */
-	m->cp_hqd_pq_control |= ffs(q->queue_size / 4) - 1 - 1;
+	m->cp_hqd_pq_control |= order_base_2(q->queue_size / 4) - 1;
 	m->cp_hqd_pq_base_lo = lower_32_bits((uint64_t)q->queue_address >> 8);
 	m->cp_hqd_pq_base_hi = upper_32_bits((uint64_t)q->queue_address >> 8);
 	m->cp_hqd_pq_rptr_report_addr_lo = lower_32_bits((uint64_t)q->read_ptr);

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

@@ -121,7 +121,7 @@ static int __update_mqd(struct mqd_manager *mm, void *mqd,
 	m->cp_hqd_pq_control = 5 << CP_HQD_PQ_CONTROL__RPTR_BLOCK_SIZE__SHIFT |
 			atc_bit << CP_HQD_PQ_CONTROL__PQ_ATC__SHIFT |
 			mtype << CP_HQD_PQ_CONTROL__MTYPE__SHIFT;
-	m->cp_hqd_pq_control |=	ffs(q->queue_size / 4) - 1 - 1;
+	m->cp_hqd_pq_control |=	order_base_2(q->queue_size / 4) - 1;
 	pr_debug("cp_hqd_pq_control 0x%x\n", m->cp_hqd_pq_control);
 
 	m->cp_hqd_pq_base_lo = lower_32_bits((uint64_t)q->queue_address >> 8);
@@ -151,7 +151,7 @@ static int __update_mqd(struct mqd_manager *mm, void *mqd,
 	 * is safe, giving a maximum field value of 0xA.
 	 */
 	m->cp_hqd_eop_control |= min(0xA,
-		ffs(q->eop_ring_buffer_size / 4) - 1 - 1);
+		order_base_2(q->eop_ring_buffer_size / 4) - 1);
 	m->cp_hqd_eop_base_addr_lo =
 			lower_32_bits(q->eop_ring_buffer_address >> 8);
 	m->cp_hqd_eop_base_addr_hi =
@@ -287,7 +287,7 @@ static int update_mqd_sdma(struct mqd_manager *mm, void *mqd,
 	struct vi_sdma_mqd *m;
 
 	m = get_sdma_mqd(mqd);
-	m->sdmax_rlcx_rb_cntl = (ffs(q->queue_size / 4) - 1)
+	m->sdmax_rlcx_rb_cntl = order_base_2(q->queue_size / 4)
 		<< SDMA0_RLC0_RB_CNTL__RB_SIZE__SHIFT |
 		q->vmid << SDMA0_RLC0_RB_CNTL__RB_VMID__SHIFT |
 		1 << SDMA0_RLC0_RB_CNTL__RPTR_WRITEBACK_ENABLE__SHIFT |