Merge branch 'mlxsw-Update-main-pool-computation-and-pool-size-limits'

Ido Schimmel says:

====================
mlxsw: Update main pool computation and pool size limits

Petr says:

In Spectrum ASICs, the shared buffer is an area of memory where packets are
kept until they can be transmitted. There are two resources associated with
shared buffer size: cap_total_buffer_size and cap_guaranteed_shared_buffer.
So far, mlxsw has been using the former as a limit when validating shared
buffer pool size configuration. However, the total size also includes
headrooms and reserved space, which really cannot be used for shared buffer
pools. Patch #1 mends this and has mlxsw use the guaranteed size.

To configure default pool sizes, mlxsw has historically hard-coded one or
two smallish pools, and one "main" pool that took most of the shared buffer
(that would be pool 0 on ingress and pool 4 on egress). During the
development of Spectrum-2, it became clear that the shared buffer size
keeps shrinking as bugs are identified and worked around. In order to
prevent having to tweak the size of pools 0 and 4 to catch up with updates
to values reported by the FW, patch #2 changes the way these pools are set.
Instead of hard-coding a fixed value, the main pool now takes whatever is
left from the guaranteed size after the smaller pool(s) are taken into
account.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/resources.h

@@ -26,7 +26,7 @@ enum mlxsw_res_id {
 	MLXSW_RES_ID_MAX_LAG_MEMBERS,
 	MLXSW_RES_ID_LOCAL_PORTS_IN_1X,
 	MLXSW_RES_ID_LOCAL_PORTS_IN_2X,
-	MLXSW_RES_ID_MAX_BUFFER_SIZE,
+	MLXSW_RES_ID_GUARANTEED_SHARED_BUFFER,
 	MLXSW_RES_ID_CELL_SIZE,
 	MLXSW_RES_ID_MAX_HEADROOM_SIZE,
 	MLXSW_RES_ID_ACL_MAX_TCAM_REGIONS,
@@ -82,7 +82,7 @@ static u16 mlxsw_res_ids[] = {
 	[MLXSW_RES_ID_MAX_LAG_MEMBERS] = 0x2521,
 	[MLXSW_RES_ID_LOCAL_PORTS_IN_1X] = 0x2610,
 	[MLXSW_RES_ID_LOCAL_PORTS_IN_2X] = 0x2611,
-	[MLXSW_RES_ID_MAX_BUFFER_SIZE] = 0x2802,	/* Bytes */
+	[MLXSW_RES_ID_GUARANTEED_SHARED_BUFFER] = 0x2805,	/* Bytes */
 	[MLXSW_RES_ID_CELL_SIZE] = 0x2803,	/* Bytes */
 	[MLXSW_RES_ID_MAX_HEADROOM_SIZE] = 0x2811,	/* Bytes */
 	[MLXSW_RES_ID_ACL_MAX_TCAM_REGIONS] = 0x2901,

drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c

@@ -35,6 +35,7 @@ struct mlxsw_sp_sb_cm {
 };
 
 #define MLXSW_SP_SB_INFI -1U
+#define MLXSW_SP_SB_REST -2U
 
 struct mlxsw_sp_sb_pm {
 	u32 min_buff;
@@ -421,19 +422,16 @@ static void mlxsw_sp_sb_ports_fini(struct mlxsw_sp *mlxsw_sp)
 		.freeze_size = _freeze_size,				\
 	}
 
-#define MLXSW_SP1_SB_PR_INGRESS_SIZE	12440000
-#define MLXSW_SP1_SB_PR_EGRESS_SIZE	13232000
 #define MLXSW_SP1_SB_PR_CPU_SIZE	(256 * 1000)
 
 /* Order according to mlxsw_sp1_sb_pool_dess */
 static const struct mlxsw_sp_sb_pr mlxsw_sp1_sb_prs[] = {
-	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC,
-		       MLXSW_SP1_SB_PR_INGRESS_SIZE),
+	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC, MLXSW_SP_SB_REST),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC, 0),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC, 0),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC, 0),
-	MLXSW_SP_SB_PR_EXT(MLXSW_REG_SBPR_MODE_DYNAMIC,
-			   MLXSW_SP1_SB_PR_EGRESS_SIZE, true, false),
+	MLXSW_SP_SB_PR_EXT(MLXSW_REG_SBPR_MODE_DYNAMIC, MLXSW_SP_SB_REST,
+			   true, false),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC, 0),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC, 0),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC, 0),
@@ -445,19 +443,16 @@ static const struct mlxsw_sp_sb_pr mlxsw_sp1_sb_prs[] = {
 			   MLXSW_SP1_SB_PR_CPU_SIZE, true, false),
 };
 
-#define MLXSW_SP2_SB_PR_INGRESS_SIZE	35297568
-#define MLXSW_SP2_SB_PR_EGRESS_SIZE	35297568
 #define MLXSW_SP2_SB_PR_CPU_SIZE	(256 * 1000)
 
 /* Order according to mlxsw_sp2_sb_pool_dess */
 static const struct mlxsw_sp_sb_pr mlxsw_sp2_sb_prs[] = {
-	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC,
-		       MLXSW_SP2_SB_PR_INGRESS_SIZE),
+	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_DYNAMIC, MLXSW_SP_SB_REST),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_STATIC, 0),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_STATIC, 0),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_STATIC, 0),
-	MLXSW_SP_SB_PR_EXT(MLXSW_REG_SBPR_MODE_DYNAMIC,
-			   MLXSW_SP2_SB_PR_EGRESS_SIZE, true, false),
+	MLXSW_SP_SB_PR_EXT(MLXSW_REG_SBPR_MODE_DYNAMIC, MLXSW_SP_SB_REST,
+			   true, false),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_STATIC, 0),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_STATIC, 0),
 	MLXSW_SP_SB_PR(MLXSW_REG_SBPR_MODE_STATIC, 0),
@@ -471,11 +466,33 @@ static const struct mlxsw_sp_sb_pr mlxsw_sp2_sb_prs[] = {
 
 static int mlxsw_sp_sb_prs_init(struct mlxsw_sp *mlxsw_sp,
 				const struct mlxsw_sp_sb_pr *prs,
+				const struct mlxsw_sp_sb_pool_des *pool_dess,
 				size_t prs_len)
 {
+	/* Round down, unlike mlxsw_sp_bytes_cells(). */
+	u32 sb_cells = mlxsw_sp->sb->sb_size / mlxsw_sp->sb->cell_size;
+	u32 rest_cells[2] = {sb_cells, sb_cells};
 	int i;
 	int err;
 
+	/* Calculate how much space to give to the "REST" pools in either
+	 * direction.
+	 */
+	for (i = 0; i < prs_len; i++) {
+		enum mlxsw_reg_sbxx_dir dir = pool_dess[i].dir;
+		u32 size = prs[i].size;
+		u32 size_cells;
+
+		if (size == MLXSW_SP_SB_INFI || size == MLXSW_SP_SB_REST)
+			continue;
+
+		size_cells = mlxsw_sp_bytes_cells(mlxsw_sp, size);
+		if (WARN_ON_ONCE(size_cells > rest_cells[dir]))
+			continue;
+
+		rest_cells[dir] -= size_cells;
+	}
+
 	for (i = 0; i < prs_len; i++) {
 		u32 size = prs[i].size;
 		u32 size_cells;
@@ -483,6 +500,10 @@ static int mlxsw_sp_sb_prs_init(struct mlxsw_sp *mlxsw_sp,
 		if (size == MLXSW_SP_SB_INFI) {
 			err = mlxsw_sp_sb_pr_write(mlxsw_sp, i, prs[i].mode,
 						   0, true);
+		} else if (size == MLXSW_SP_SB_REST) {
+			size_cells = rest_cells[pool_dess[i].dir];
+			err = mlxsw_sp_sb_pr_write(mlxsw_sp, i, prs[i].mode,
+						   size_cells, false);
 		} else {
 			size_cells = mlxsw_sp_bytes_cells(mlxsw_sp, size);
 			err = mlxsw_sp_sb_pr_write(mlxsw_sp, i, prs[i].mode,
@@ -904,7 +925,7 @@ int mlxsw_sp_buffers_init(struct mlxsw_sp *mlxsw_sp)
 	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, CELL_SIZE))
 		return -EIO;
 
-	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, MAX_BUFFER_SIZE))
+	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, GUARANTEED_SHARED_BUFFER))
 		return -EIO;
 
 	if (!MLXSW_CORE_RES_VALID(mlxsw_sp->core, MAX_HEADROOM_SIZE))
@@ -915,7 +936,7 @@ int mlxsw_sp_buffers_init(struct mlxsw_sp *mlxsw_sp)
 		return -ENOMEM;
 	mlxsw_sp->sb->cell_size = MLXSW_CORE_RES_GET(mlxsw_sp->core, CELL_SIZE);
 	mlxsw_sp->sb->sb_size = MLXSW_CORE_RES_GET(mlxsw_sp->core,
-						   MAX_BUFFER_SIZE);
+						   GUARANTEED_SHARED_BUFFER);
 	max_headroom_size = MLXSW_CORE_RES_GET(mlxsw_sp->core,
 					       MAX_HEADROOM_SIZE);
 	/* Round down, because this limit must not be overstepped. */
@@ -926,6 +947,7 @@ int mlxsw_sp_buffers_init(struct mlxsw_sp *mlxsw_sp)
 	if (err)
 		goto err_sb_ports_init;
 	err = mlxsw_sp_sb_prs_init(mlxsw_sp, mlxsw_sp->sb_vals->prs,
+				   mlxsw_sp->sb_vals->pool_dess,
 				   mlxsw_sp->sb_vals->pool_count);
 	if (err)
 		goto err_sb_prs_init;
@@ -1013,7 +1035,8 @@ int mlxsw_sp_sb_pool_set(struct mlxsw_core *mlxsw_core,
 	mode = (enum mlxsw_reg_sbpr_mode) threshold_type;
 	pr = &mlxsw_sp->sb_vals->prs[pool_index];
 
-	if (size > MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_BUFFER_SIZE)) {
+	if (size > MLXSW_CORE_RES_GET(mlxsw_sp->core,
+				      GUARANTEED_SHARED_BUFFER)) {
 		NL_SET_ERR_MSG_MOD(extack, "Exceeded shared buffer size");
 		return -EINVAL;
 	}

drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c

@@ -305,7 +305,8 @@ mlxsw_sp_qdisc_red_check_params(struct mlxsw_sp_port *mlxsw_sp_port,
 			p->max);
 		return -EINVAL;
 	}
-	if (p->max > MLXSW_CORE_RES_GET(mlxsw_sp->core, MAX_BUFFER_SIZE)) {
+	if (p->max > MLXSW_CORE_RES_GET(mlxsw_sp->core,
+					GUARANTEED_SHARED_BUFFER)) {
 		dev_err(mlxsw_sp->bus_info->dev,
 			"spectrum: RED: max value %u is too big\n", p->max);
 		return -EINVAL;