net: hns3: divide shared buffer between TC

Currently hardware may have not enough buffer to receive packet
when it has used more than two MPS(maximum packet size) of
buffer, but there are still a lot of shared buffer left unused
when TC num is small.

This patch divides shared buffer to be used between TC when
the port supports DCB, and adjusts the waterline and threshold
according to user manual for the port that does not support
DCB.

This patch also change hclge_get_tc_num's return type to u32
to avoid signed-unsigned mix with divide.
Signed-off-by: NYunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: NHuazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_main.c

@@ -1422,7 +1422,7 @@ static int hclge_tx_buffer_alloc(struct hclge_dev *hdev,
 	return ret;
 }
 
-static int hclge_get_tc_num(struct hclge_dev *hdev)
+static u32 hclge_get_tc_num(struct hclge_dev *hdev)
 {
 	int i, cnt = 0;
 
@@ -1495,8 +1495,8 @@ static bool  hclge_is_rx_buf_ok(struct hclge_dev *hdev,
 				struct hclge_pkt_buf_alloc *buf_alloc,
 				u32 rx_all)
 {
-	u32 shared_buf_min, shared_buf_tc, shared_std;
-	int tc_num = hclge_get_tc_num(hdev);
+	u32 shared_buf_min, shared_buf_tc, shared_std, hi_thrd, lo_thrd;
+	u32 tc_num = hclge_get_tc_num(hdev);
 	u32 shared_buf, aligned_mps;
 	u32 rx_priv;
 	int i;
@@ -1526,13 +1526,26 @@ static bool  hclge_is_rx_buf_ok(struct hclge_dev *hdev,
 	} else {
 		buf_alloc->s_buf.self.high = aligned_mps +
 						HCLGE_NON_DCB_ADDITIONAL_BUF;
-		buf_alloc->s_buf.self.low =
-			roundup(aligned_mps / 2, HCLGE_BUF_SIZE_UNIT);
+		buf_alloc->s_buf.self.low = aligned_mps;
+	}
+
+	if (hnae3_dev_dcb_supported(hdev)) {
+		if (tc_num)
+			hi_thrd = (shared_buf - hdev->dv_buf_size) / tc_num;
+		else
+			hi_thrd = shared_buf - hdev->dv_buf_size;
+
+		hi_thrd = max_t(u32, hi_thrd, 2 * aligned_mps);
+		hi_thrd = rounddown(hi_thrd, HCLGE_BUF_SIZE_UNIT);
+		lo_thrd = hi_thrd - aligned_mps / 2;
+	} else {
+		hi_thrd = aligned_mps + HCLGE_NON_DCB_ADDITIONAL_BUF;
+		lo_thrd = aligned_mps;
 	}
 
 	for (i = 0; i < HCLGE_MAX_TC_NUM; i++) {
-		buf_alloc->s_buf.tc_thrd[i].low = aligned_mps;
-		buf_alloc->s_buf.tc_thrd[i].high = 2 * aligned_mps;
+		buf_alloc->s_buf.tc_thrd[i].low = lo_thrd;
+		buf_alloc->s_buf.tc_thrd[i].high = hi_thrd;
 	}
 
 	return true;