Merge branch 'am65-cpsw-rx-dscp-prio-map'

Roger Quadros says:

====================
net: ethernet: ti: am65-cpsw: enable DSCP to priority map for RX

Configure default DSCP to User Priority mapping registers as per:
 https://datatracker.ietf.org/doc/html/rfc8325#section-4.3
and
 https://datatracker.ietf.org/doc/html/rfc8622#section-11

Also update Priority to Thread maping to be compliant with
IEEE802.1Q-2014. Priority Code Point (PCP) 2 is higher priority than
PCP 0 (Best Effort). PCP 1 (Background) is lower priority than
PCP 0 (Best Effort).

---
Changes in v4:
- Updated default DSCP to User Priority mapping as per
  https://datatracker.ietf.org/doc/html/rfc8325#section-4.3
  and
  https://datatracker.ietf.org/doc/html/rfc8622#section-11
- Link to v3: https://lore.kernel.org/r/20241109-am65-cpsw-multi-rx-dscp-v3-0-1cfb76928490@kernel.org

Changes in v3:
- Added Reviewed-by tag to patch 1
- Added macros for DSCP PRI field size and DSCP PRI per register
- Drop unnecessary readl() in am65_cpsw_port_set_dscp_map()
- Link to v2: https://lore.kernel.org/r/20241107-am65-cpsw-multi-rx-dscp-v2-0-9e9cd1920035@kernel.org

Changes in v2:
- Updated references to more recent standard IEEE802.1Q-2014.
- Dropped reference to web link which might change in the future.
- Typo fix in commit log.
- Link to v1: https://lore.kernel.org/r/20241105-am65-cpsw-multi-rx-dscp-v1-0-38db85333c88@kernel.org
====================

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 122 insertions, 14 deletions

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 47fb5af16796..14e1df721f2e 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -71,6 +71,8 @@
 #define AM65_CPSW_PORT_REG_RX_PRI_MAP		0x020
 #define AM65_CPSW_PORT_REG_RX_MAXLEN		0x024
 
+#define AM65_CPSW_PORTN_REG_CTL			0x004
+#define AM65_CPSW_PORTN_REG_DSCP_MAP		0x120
 #define AM65_CPSW_PORTN_REG_SA_L		0x308
 #define AM65_CPSW_PORTN_REG_SA_H		0x30c
 #define AM65_CPSW_PORTN_REG_TS_CTL              0x310
@@ -94,6 +96,10 @@
 /* AM65_CPSW_PORT_REG_PRI_CTL */
 #define AM65_CPSW_PORT_REG_PRI_CTL_RX_PTYPE_RROBIN	BIT(8)
 
+/* AM65_CPSW_PN_REG_CTL */
+#define AM65_CPSW_PN_REG_CTL_DSCP_IPV4_EN	BIT(1)
+#define AM65_CPSW_PN_REG_CTL_DSCP_IPV6_EN	BIT(2)
+
 /* AM65_CPSW_PN_TS_CTL register fields */
 #define AM65_CPSW_PN_TS_CTL_TX_ANX_F_EN		BIT(4)
 #define AM65_CPSW_PN_TS_CTL_TX_VLAN_LT1_EN	BIT(5)
@@ -176,6 +182,99 @@ static void am65_cpsw_port_set_sl_mac(struct am65_cpsw_port *slave,
 	writel(mac_lo, slave->port_base + AM65_CPSW_PORTN_REG_SA_L);
 }
 
+#define AM65_CPSW_DSCP_MAX	GENMASK(5, 0)
+#define AM65_CPSW_PRI_MAX	GENMASK(2, 0)
+#define AM65_CPSW_DSCP_PRI_PER_REG	8
+#define AM65_CPSW_DSCP_PRI_SIZE		4	/* in bits */
+static int am65_cpsw_port_set_dscp_map(struct am65_cpsw_port *slave, u8 dscp, u8 pri)
+{
+	int reg_ofs;
+	int bit_ofs;
+	u32 val;
+
+	if (dscp > AM65_CPSW_DSCP_MAX)
+		return -EINVAL;
+
+	if (pri > AM65_CPSW_PRI_MAX)
+		return -EINVAL;
+
+	/* 32-bit register offset to this dscp */
+	reg_ofs = (dscp / AM65_CPSW_DSCP_PRI_PER_REG) * 4;
+	/* bit field offset to this dscp */
+	bit_ofs = AM65_CPSW_DSCP_PRI_SIZE * (dscp % AM65_CPSW_DSCP_PRI_PER_REG);
+
+	val = readl(slave->port_base + AM65_CPSW_PORTN_REG_DSCP_MAP + reg_ofs);
+	val &= ~(AM65_CPSW_PRI_MAX << bit_ofs);	/* clear */
+	val |= pri << bit_ofs;			/* set */
+	writel(val, slave->port_base + AM65_CPSW_PORTN_REG_DSCP_MAP + reg_ofs);
+
+	return 0;
+}
+
+static void am65_cpsw_port_enable_dscp_map(struct am65_cpsw_port *slave)
+{
+	int dscp, pri;
+	u32 val;
+
+	/* Default DSCP to User Priority mapping as per:
+	 * https://datatracker.ietf.org/doc/html/rfc8325#section-4.3
+	 * and
+	 * https://datatracker.ietf.org/doc/html/rfc8622#section-11
+	 */
+	for (dscp = 0; dscp <= AM65_CPSW_DSCP_MAX; dscp++) {
+		switch (dscp) {
+		case 56:	/* CS7 */
+		case 48:	/* CS6 */
+			pri = 7;
+			break;
+		case 46:	/* EF */
+		case 44:	/* VA */
+			pri = 6;
+			break;
+		case 40:	/* CS5 */
+			pri = 5;
+			break;
+		case 34:	/* AF41 */
+		case 36:	/* AF42 */
+		case 38:	/* AF43 */
+		case 32:	/* CS4 */
+		case 26:	/* AF31 */
+		case 28:	/* AF32 */
+		case 30:	/* AF33 */
+		case 24:	/* CS3 */
+			pri = 4;
+			break;
+		case 18:	/* AF21 */
+		case 20:	/* AF22 */
+		case 22:	/* AF23 */
+			pri = 3;
+			break;
+		case 16:	/* CS2 */
+		case 10:	/* AF11 */
+		case 12:	/* AF12 */
+		case 14:	/* AF13 */
+		case 0:		/* DF */
+			pri = 0;
+			break;
+		case 8:		/* CS1 */
+		case 1:		/* LE */
+			pri = 1;
+			break;
+		default:
+			pri = 0;
+			break;
+		}
+
+		am65_cpsw_port_set_dscp_map(slave, dscp, pri);
+	}
+
+	/* enable port IPV4 and IPV6 DSCP for this port */
+	val = readl(slave->port_base + AM65_CPSW_PORTN_REG_CTL);
+	val |= AM65_CPSW_PN_REG_CTL_DSCP_IPV4_EN |
+		AM65_CPSW_PN_REG_CTL_DSCP_IPV6_EN;
+	writel(val, slave->port_base + AM65_CPSW_PORTN_REG_CTL);
+}
+
 static void am65_cpsw_sl_ctl_reset(struct am65_cpsw_port *port)
 {
 	cpsw_sl_reset(port->slave.mac_sl, 100);
@@ -916,6 +1015,7 @@ static int am65_cpsw_nuss_ndo_slave_open(struct net_device *ndev)
 	common->usage_count++;
 
 	am65_cpsw_port_set_sl_mac(port, ndev->dev_addr);
+	am65_cpsw_port_enable_dscp_map(port);
 
 	if (common->is_emac_mode)
 		am65_cpsw_init_port_emac_ale(port);
diff --git a/drivers/net/ethernet/ti/cpsw_ale.c b/drivers/net/ethernet/ti/cpsw_ale.c
index d361caa80d05..52e4e350b734 100644
--- a/drivers/net/ethernet/ti/cpsw_ale.c
+++ b/drivers/net/ethernet/ti/cpsw_ale.c
@@ -1704,26 +1704,34 @@ static void cpsw_ale_policer_reset(struct cpsw_ale *ale)
 void cpsw_ale_classifier_setup_default(struct cpsw_ale *ale, int num_rx_ch)
 {
 	int pri, idx;
-	/* IEEE802.1D-2004, Standard for Local and metropolitan area networks
-	 *    Table G-2 - Traffic type acronyms
-	 *    Table G-3 - Defining traffic types
-	 * User priority values 1 and 2 effectively communicate a lower
-	 * priority than 0. In the below table 0 is assigned to higher priority
-	 * thread than 1 and 2 wherever possible.
-	 * The below table maps which thread the user priority needs to be
+
+	/* Reference:
+	 * IEEE802.1Q-2014, Standard for Local and metropolitan area networks
+	 *    Table I-2 - Traffic type acronyms
+	 *    Table I-3 - Defining traffic types
+	 * Section I.4 Traffic types and priority values, states:
+	 * "0 is thus used both for default priority and for Best Effort, and
+	 *  Background is associated with a priority value of 1. This means
+	 * that the value 1 effectively communicates a lower priority than 0."
+	 *
+	 * In the table below, Priority Code Point (PCP) 0 is assigned
+	 * to a higher priority thread than PCP 1 wherever possible.
+	 * The table maps which thread the PCP traffic needs to be
 	 * sent to for a given number of threads (RX channels). Upper threads
 	 * have higher priority.
 	 * e.g. if number of threads is 8 then user priority 0 will map to
-	 * pri_thread_map[8-1][0] i.e. thread 2
+	 * pri_thread_map[8-1][0] i.e. thread 1
 	 */
-	int pri_thread_map[8][8] = {	{ 0, 0, 0, 0, 0, 0, 0, 0, },
+
+	int pri_thread_map[8][8] = {   /* BK,BE,EE,CA,VI,VO,IC,NC */
+					{ 0, 0, 0, 0, 0, 0, 0, 0, },
 					{ 0, 0, 0, 0, 1, 1, 1, 1, },
 					{ 0, 0, 0, 0, 1, 1, 2, 2, },
-					{ 1, 0, 0, 1, 2, 2, 3, 3, },
-					{ 1, 0, 0, 1, 2, 3, 4, 4, },
-					{ 1, 0, 0, 2, 3, 4, 5, 5, },
-					{ 1, 0, 0, 2, 3, 4, 5, 6, },
-					{ 2, 0, 1, 3, 4, 5, 6, 7, } };
+					{ 0, 0, 1, 1, 2, 2, 3, 3, },
+					{ 0, 0, 1, 1, 2, 2, 3, 4, },
+					{ 1, 0, 2, 2, 3, 3, 4, 5, },
+					{ 1, 0, 2, 3, 4, 4, 5, 6, },
+					{ 1, 0, 2, 3, 4, 5, 6, 7 } };
 
 	cpsw_ale_policer_reset(ale);