net: dsa: realtek: rtl8365mb: handle PHY interface modes correctly

Realtek switches in the rtl8365mb family always have at least one port
with a so-called external interface, supporting PHY interface modes such
as RGMII or SGMII. The purpose of this patch is to improve the driver's
handling of these ports.

A new struct rtl8365mb_chip_info is introduced together with a static
array of such structs. An instance of this struct is added for each
supported switch, distinguished by its chip ID and version. Embedded in
each chip_info struct is an array of struct rtl8365mb_extint, describing
the external interfaces available. This is more specific than the old
rtl8365mb_extint_port_map, which was only valid for switches with up to
6 ports.

The struct rtl8365mb_extint also contains a bitmask of supported PHY
interface modes, which allows the driver to distinguish which ports
support RGMII. This corrects a previous mistake in the driver whereby it
was assumed that any port with an external interface supports RGMII.
This is not actually the case: for example, the RTL8367S has two
external interfaces, only the second of which supports RGMII. The first
supports only SGMII and HSGMII. This new design will make it easier to
add support for other interface modes.

Finally, rtl8365mb_phylink_get_caps() is fixed up to return supported
capabilities based on the external interface properties described above.
This addresses Vladimir's point in the linked thread that the
capabilities are not actually a function of the DSA port type: Although
most typical applications will treat the ports with internal PHY as user
ports, there is no actual hardware limitation preventing one from using
them as a CPU port. Equally, ports with external interface(s) may well
be treated as user ports, even though it is typical to use those ports
as CPU ports.

Link: https://lore.kernel.org/netdev/20220510192301.5djdt3ghoavxulhl@bang-olufsen.dk/
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 174 insertions, 107 deletions

diff --git a/drivers/net/dsa/realtek/rtl8365mb.c b/drivers/net/dsa/realtek/rtl8365mb.c
index 676b88798976..da31d8b839ac 100644
--- a/drivers/net/dsa/realtek/rtl8365mb.c
+++ b/drivers/net/dsa/realtek/rtl8365mb.c
@@ -101,26 +101,14 @@
 
 #include "realtek.h"
 
-/* Chip-specific data and limits */
-#define RTL8365MB_CHIP_ID_8365MB_VC	0x6367
-#define RTL8365MB_CHIP_VER_8365MB_VC	0x0040
-
-#define RTL8365MB_CHIP_ID_8367S		0x6367
-#define RTL8365MB_CHIP_VER_8367S	0x00A0
-
-#define RTL8365MB_CHIP_ID_8367RB_VB	0x6367
-#define RTL8365MB_CHIP_VER_8367RB_VB	0x0020
-
 /* Family-specific data and limits */
 #define RTL8365MB_PHYADDRMAX		7
 #define RTL8365MB_NUM_PHYREGS		32
 #define RTL8365MB_PHYREGMAX		(RTL8365MB_NUM_PHYREGS - 1)
 #define RTL8365MB_MAX_NUM_PORTS		11
+#define RTL8365MB_MAX_NUM_EXTINTS	3
 #define RTL8365MB_LEARN_LIMIT_MAX	2112
 
-/* valid for all 6-port or less variants */
-static const int rtl8365mb_extint_port_map[]  = { -1, -1, -1, -1, -1, -1, 1, 2, -1, -1};
-
 /* Chip identification registers */
 #define RTL8365MB_CHIP_ID_REG		0x1300
 
@@ -200,7 +188,7 @@ static const int rtl8365mb_extint_port_map[]  = { -1, -1, -1, -1, -1, -1, 1, 2,
 /* The PHY OCP addresses of PHY registers 0~31 start here */
 #define RTL8365MB_PHY_OCP_ADDR_PHYREG_BASE		0xA400
 
-/* EXT interface port mode values - used in DIGITAL_INTERFACE_SELECT */
+/* External interface port mode values - used in DIGITAL_INTERFACE_SELECT */
 #define RTL8365MB_EXT_PORT_MODE_DISABLE		0
 #define RTL8365MB_EXT_PORT_MODE_RGMII		1
 #define RTL8365MB_EXT_PORT_MODE_MII_MAC		2
@@ -216,19 +204,7 @@ static const int rtl8365mb_extint_port_map[]  = { -1, -1, -1, -1, -1, -1, 1, 2,
 #define RTL8365MB_EXT_PORT_MODE_1000X		12
 #define RTL8365MB_EXT_PORT_MODE_100FX		13
 
-/* Realtek docs and driver uses logic number as EXT_PORT0=16, EXT_PORT1=17,
- * EXT_PORT2=18, to interact with switch ports. That logic number is internally
- * converted to either a physical port number (0..9) or an external interface id (0..2),
- * depending on which function was called. The external interface id is calculated as
- * (ext_id=logic_port-15), while the logical to physical map depends on the chip id/version.
- *
- * EXT_PORT0 mentioned in datasheets and rtl8367c driver is used in this driver
- * as extid==1, EXT_PORT2, mentioned in Realtek rtl8367c driver for 10-port switches,
- * would have an ext_id of 3 (out of range for most extint macros) and ext_id 0 does
- * not seem to be used as well for this family.
- */
-
-/* EXT interface mode configuration registers 0~1 */
+/* External interface mode configuration registers 0~1 */
 #define RTL8365MB_DIGITAL_INTERFACE_SELECT_REG0		0x1305 /* EXT1 */
 #define RTL8365MB_DIGITAL_INTERFACE_SELECT_REG1		0x13C3 /* EXT2 */
 #define RTL8365MB_DIGITAL_INTERFACE_SELECT_REG(_extint) \
@@ -240,7 +216,7 @@ static const int rtl8365mb_extint_port_map[]  = { -1, -1, -1, -1, -1, -1, 1, 2,
 #define   RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_OFFSET(_extint) \
 		(((_extint) % 2) * 4)
 
-/* EXT interface RGMII TX/RX delay configuration registers 0~2 */
+/* External interface RGMII TX/RX delay configuration registers 0~2 */
 #define RTL8365MB_EXT_RGMXF_REG0		0x1306 /* EXT0 */
 #define RTL8365MB_EXT_RGMXF_REG1		0x1307 /* EXT1 */
 #define RTL8365MB_EXT_RGMXF_REG2		0x13C5 /* EXT2 */
@@ -257,7 +233,7 @@ static const int rtl8365mb_extint_port_map[]  = { -1, -1, -1, -1, -1, -1, 1, 2,
 #define RTL8365MB_PORT_SPEED_100M	1
 #define RTL8365MB_PORT_SPEED_1000M	2
 
-/* EXT interface force configuration registers 0~2 */
+/* External interface force configuration registers 0~2 */
 #define RTL8365MB_DIGITAL_INTERFACE_FORCE_REG0		0x1310 /* EXT0 */
 #define RTL8365MB_DIGITAL_INTERFACE_FORCE_REG1		0x1311 /* EXT1 */
 #define RTL8365MB_DIGITAL_INTERFACE_FORCE_REG2		0x13C4 /* EXT2 */
@@ -489,6 +465,95 @@ static const struct rtl8365mb_jam_tbl_entry rtl8365mb_init_jam_common[] = {
 	{ 0x1D32, 0x0002 },
 };
 
+enum rtl8365mb_phy_interface_mode {
+	RTL8365MB_PHY_INTERFACE_MODE_INVAL = 0,
+	RTL8365MB_PHY_INTERFACE_MODE_INTERNAL = BIT(0),
+	RTL8365MB_PHY_INTERFACE_MODE_MII = BIT(1),
+	RTL8365MB_PHY_INTERFACE_MODE_TMII = BIT(2),
+	RTL8365MB_PHY_INTERFACE_MODE_RMII = BIT(3),
+	RTL8365MB_PHY_INTERFACE_MODE_RGMII = BIT(4),
+	RTL8365MB_PHY_INTERFACE_MODE_SGMII = BIT(5),
+	RTL8365MB_PHY_INTERFACE_MODE_HSGMII = BIT(6),
+};
+
+/**
+ * struct rtl8365mb_extint - external interface info
+ * @port: the port with an external interface
+ * @id: the external interface ID, which is either 0, 1, or 2
+ * @supported_interfaces: a bitmask of supported PHY interface modes
+ *
+ * Represents a mapping: port -> { id, supported_interfaces }. To be embedded
+ * in &struct rtl8365mb_chip_info for every port with an external interface.
+ */
+struct rtl8365mb_extint {
+	int port;
+	int id;
+	unsigned int supported_interfaces;
+};
+
+/**
+ * struct rtl8365mb_chip_info - static chip-specific info
+ * @name: human-readable chip name
+ * @chip_id: chip identifier
+ * @chip_ver: chip silicon revision
+ * @extints: available external interfaces
+ * @jam_table: chip-specific initialization jam table
+ * @jam_size: size of the chip's jam table
+ *
+ * These data are specific to a given chip in the family of switches supported
+ * by this driver. When adding support for another chip in the family, a new
+ * chip info should be added to the rtl8365mb_chip_infos array.
+ */
+struct rtl8365mb_chip_info {
+	const char *name;
+	u32 chip_id;
+	u32 chip_ver;
+	const struct rtl8365mb_extint extints[RTL8365MB_MAX_NUM_EXTINTS];
+	const struct rtl8365mb_jam_tbl_entry *jam_table;
+	size_t jam_size;
+};
+
+/* Chip info for each supported switch in the family */
+#define PHY_INTF(_mode) (RTL8365MB_PHY_INTERFACE_MODE_ ## _mode)
+static const struct rtl8365mb_chip_info rtl8365mb_chip_infos[] = {
+	{
+		.name = "RTL8365MB-VC",
+		.chip_id = 0x6367,
+		.chip_ver = 0x0040,
+		.extints = {
+			{ 6, 1, PHY_INTF(MII) | PHY_INTF(TMII) |
+				PHY_INTF(RMII) | PHY_INTF(RGMII) },
+		},
+		.jam_table = rtl8365mb_init_jam_8365mb_vc,
+		.jam_size = ARRAY_SIZE(rtl8365mb_init_jam_8365mb_vc),
+	},
+	{
+		.name = "RTL8367S",
+		.chip_id = 0x6367,
+		.chip_ver = 0x00A0,
+		.extints = {
+			{ 6, 1, PHY_INTF(SGMII) | PHY_INTF(HSGMII) },
+			{ 7, 2, PHY_INTF(MII) | PHY_INTF(TMII) |
+				PHY_INTF(RMII) | PHY_INTF(RGMII) },
+		},
+		.jam_table = rtl8365mb_init_jam_8365mb_vc,
+		.jam_size = ARRAY_SIZE(rtl8365mb_init_jam_8365mb_vc),
+	},
+	{
+		.name = "RTL8367RB-VB",
+		.chip_id = 0x6367,
+		.chip_ver = 0x0020,
+		.extints = {
+			{ 6, 1, PHY_INTF(MII) | PHY_INTF(TMII) |
+				PHY_INTF(RMII) | PHY_INTF(RGMII) },
+			{ 7, 2, PHY_INTF(MII) | PHY_INTF(TMII) |
+				PHY_INTF(RMII) | PHY_INTF(RGMII) },
+		},
+		.jam_table = rtl8365mb_init_jam_8365mb_vc,
+		.jam_size = ARRAY_SIZE(rtl8365mb_init_jam_8365mb_vc),
+	},
+};
+
 enum rtl8365mb_stp_state {
 	RTL8365MB_STP_STATE_DISABLED = 0,
 	RTL8365MB_STP_STATE_BLOCKING = 1,
@@ -558,29 +623,23 @@ struct rtl8365mb_port {
 };
 
 /**
- * struct rtl8365mb - private chip-specific driver data
+ * struct rtl8365mb - driver private data
  * @priv: pointer to parent realtek_priv data
  * @irq: registered IRQ or zero
- * @chip_id: chip identifier
- * @chip_ver: chip silicon revision
+ * @chip_info: chip-specific info about the attached switch
  * @cpu: CPU tagging and CPU port configuration for this chip
  * @mib_lock: prevent concurrent reads of MIB counters
  * @ports: per-port data
- * @jam_table: chip-specific initialization jam table
- * @jam_size: size of the chip's jam table
  *
  * Private data for this driver.
  */
 struct rtl8365mb {
 	struct realtek_priv *priv;
 	int irq;
-	u32 chip_id;
-	u32 chip_ver;
+	const struct rtl8365mb_chip_info *chip_info;
 	struct rtl8365mb_cpu cpu;
 	struct mutex mib_lock;
 	struct rtl8365mb_port ports[RTL8365MB_MAX_NUM_PORTS];
-	const struct rtl8365mb_jam_tbl_entry *jam_table;
-	size_t jam_size;
 };
 
 static int rtl8365mb_phy_poll_busy(struct realtek_priv *priv)
@@ -775,6 +834,26 @@ static int rtl8365mb_dsa_phy_write(struct dsa_switch *ds, int phy, int regnum,
 	return rtl8365mb_phy_write(ds->priv, phy, regnum, val);
 }
 
+static const struct rtl8365mb_extint *
+rtl8365mb_get_port_extint(struct realtek_priv *priv, int port)
+{
+	struct rtl8365mb *mb = priv->chip_data;
+	int i;
+
+	for (i = 0; i < RTL8365MB_MAX_NUM_EXTINTS; i++) {
+		const struct rtl8365mb_extint *extint =
+			&mb->chip_info->extints[i];
+
+		if (!extint->supported_interfaces)
+			continue;
+
+		if (extint->port == port)
+			return extint;
+	}
+
+	return NULL;
+}
+
 static enum dsa_tag_protocol
 rtl8365mb_get_tag_protocol(struct dsa_switch *ds, int port,
 			   enum dsa_tag_protocol mp)
@@ -795,20 +874,17 @@ rtl8365mb_get_tag_protocol(struct dsa_switch *ds, int port,
 static int rtl8365mb_ext_config_rgmii(struct realtek_priv *priv, int port,
 				      phy_interface_t interface)
 {
+	const struct rtl8365mb_extint *extint =
+		rtl8365mb_get_port_extint(priv, port);
 	struct device_node *dn;
 	struct dsa_port *dp;
 	int tx_delay = 0;
 	int rx_delay = 0;
-	int ext_int;
 	u32 val;
 	int ret;
 
-	ext_int = rtl8365mb_extint_port_map[port];
-
-	if (ext_int <= 0) {
-		dev_err(priv->dev, "Port %d is not an external interface port\n", port);
-		return -EINVAL;
-	}
+	if (!extint)
+		return -ENODEV;
 
 	dp = dsa_to_port(priv->ds, port);
 	dn = dp->dn;
@@ -842,7 +918,7 @@ static int rtl8365mb_ext_config_rgmii(struct realtek_priv *priv, int port,
 			tx_delay = val / 2;
 		else
 			dev_warn(priv->dev,
-				 "EXT interface TX delay must be 0 or 2 ns\n");
+				 "RGMII TX delay must be 0 or 2 ns\n");
 	}
 
 	if (!of_property_read_u32(dn, "rx-internal-delay-ps", &val)) {
@@ -852,11 +928,11 @@ static int rtl8365mb_ext_config_rgmii(struct realtek_priv *priv, int port,
 			rx_delay = val;
 		else
 			dev_warn(priv->dev,
-				 "EXT interface RX delay must be 0 to 2.1 ns\n");
+				 "RGMII RX delay must be 0 to 2.1 ns\n");
 	}
 
 	ret = regmap_update_bits(
-		priv->map, RTL8365MB_EXT_RGMXF_REG(ext_int),
+		priv->map, RTL8365MB_EXT_RGMXF_REG(extint->id),
 		RTL8365MB_EXT_RGMXF_TXDELAY_MASK |
 			RTL8365MB_EXT_RGMXF_RXDELAY_MASK,
 		FIELD_PREP(RTL8365MB_EXT_RGMXF_TXDELAY_MASK, tx_delay) |
@@ -865,11 +941,11 @@ static int rtl8365mb_ext_config_rgmii(struct realtek_priv *priv, int port,
 		return ret;
 
 	ret = regmap_update_bits(
-		priv->map, RTL8365MB_DIGITAL_INTERFACE_SELECT_REG(ext_int),
-		RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_MASK(ext_int),
+		priv->map, RTL8365MB_DIGITAL_INTERFACE_SELECT_REG(extint->id),
+		RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_MASK(extint->id),
 		RTL8365MB_EXT_PORT_MODE_RGMII
 			<< RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_OFFSET(
-				   ext_int));
+				   extint->id));
 	if (ret)
 		return ret;
 
@@ -880,21 +956,18 @@ static int rtl8365mb_ext_config_forcemode(struct realtek_priv *priv, int port,
 					  bool link, int speed, int duplex,
 					  bool tx_pause, bool rx_pause)
 {
+	const struct rtl8365mb_extint *extint =
+		rtl8365mb_get_port_extint(priv, port);
 	u32 r_tx_pause;
 	u32 r_rx_pause;
 	u32 r_duplex;
 	u32 r_speed;
 	u32 r_link;
-	int ext_int;
 	int val;
 	int ret;
 
-	ext_int = rtl8365mb_extint_port_map[port];
-
-	if (ext_int <= 0) {
-		dev_err(priv->dev, "Port %d is not an external interface port\n", port);
-		return -EINVAL;
-	}
+	if (!extint)
+		return -ENODEV;
 
 	if (link) {
 		/* Force the link up with the desired configuration */
@@ -942,7 +1015,7 @@ static int rtl8365mb_ext_config_forcemode(struct realtek_priv *priv, int port,
 			 r_duplex) |
 	      FIELD_PREP(RTL8365MB_DIGITAL_INTERFACE_FORCE_SPEED_MASK, r_speed);
 	ret = regmap_write(priv->map,
-			   RTL8365MB_DIGITAL_INTERFACE_FORCE_REG(ext_int),
+			   RTL8365MB_DIGITAL_INTERFACE_FORCE_REG(extint->id),
 			   val);
 	if (ret)
 		return ret;
@@ -953,7 +1026,13 @@ static int rtl8365mb_ext_config_forcemode(struct realtek_priv *priv, int port,
 static void rtl8365mb_phylink_get_caps(struct dsa_switch *ds, int port,
 				       struct phylink_config *config)
 {
-	if (dsa_is_user_port(ds, port)) {
+	const struct rtl8365mb_extint *extint =
+		rtl8365mb_get_port_extint(ds->priv, port);
+
+	config->mac_capabilities = MAC_SYM_PAUSE | MAC_ASYM_PAUSE |
+				   MAC_10 | MAC_100 | MAC_1000FD;
+
+	if (!extint) {
 		__set_bit(PHY_INTERFACE_MODE_INTERNAL,
 			  config->supported_interfaces);
 
@@ -962,12 +1041,16 @@ static void rtl8365mb_phylink_get_caps(struct dsa_switch *ds, int port,
 		 */
 		__set_bit(PHY_INTERFACE_MODE_GMII,
 			  config->supported_interfaces);
-	} else if (dsa_is_cpu_port(ds, port)) {
-		phy_interface_set_rgmii(config->supported_interfaces);
+		return;
 	}
 
-	config->mac_capabilities = MAC_SYM_PAUSE | MAC_ASYM_PAUSE |
-				   MAC_10 | MAC_100 | MAC_1000FD;
+	/* Populate according to the modes supported by _this driver_,
+	 * not necessarily the modes supported by the hardware, some of
+	 * which remain unimplemented.
+	 */
+
+	if (extint->supported_interfaces & RTL8365MB_PHY_INTERFACE_MODE_RGMII)
+		phy_interface_set_rgmii(config->supported_interfaces);
 }
 
 static void rtl8365mb_phylink_mac_config(struct dsa_switch *ds, int port,
@@ -1782,14 +1865,17 @@ static int rtl8365mb_change_tag_protocol(struct dsa_switch *ds,
 static int rtl8365mb_switch_init(struct realtek_priv *priv)
 {
 	struct rtl8365mb *mb = priv->chip_data;
+	const struct rtl8365mb_chip_info *ci;
 	int ret;
 	int i;
 
+	ci = mb->chip_info;
+
 	/* Do any chip-specific init jam before getting to the common stuff */
-	if (mb->jam_table) {
-		for (i = 0; i < mb->jam_size; i++) {
-			ret = regmap_write(priv->map, mb->jam_table[i].reg,
-					   mb->jam_table[i].val);
+	if (ci->jam_table) {
+		for (i = 0; i < ci->jam_size; i++) {
+			ret = regmap_write(priv->map, ci->jam_table[i].reg,
+					   ci->jam_table[i].val);
 			if (ret)
 				return ret;
 		}
@@ -1962,6 +2048,7 @@ static int rtl8365mb_detect(struct realtek_priv *priv)
 	u32 chip_id;
 	u32 chip_ver;
 	int ret;
+	int i;
 
 	ret = rtl8365mb_get_chip_id_and_ver(priv->map, &chip_id, &chip_ver);
 	if (ret) {
@@ -1970,52 +2057,32 @@ static int rtl8365mb_detect(struct realtek_priv *priv)
 		return ret;
 	}
 
-	switch (chip_id) {
-	case RTL8365MB_CHIP_ID_8365MB_VC:
-		switch (chip_ver) {
-		case RTL8365MB_CHIP_VER_8365MB_VC:
-			dev_info(priv->dev,
-				 "found an RTL8365MB-VC switch (ver=0x%04x)\n",
-				 chip_ver);
-			break;
-		case RTL8365MB_CHIP_VER_8367RB_VB:
-			dev_info(priv->dev,
-				 "found an RTL8367RB-VB switch (ver=0x%04x)\n",
-				 chip_ver);
-			break;
-		case RTL8365MB_CHIP_VER_8367S:
-			dev_info(priv->dev,
-				 "found an RTL8367S switch (ver=0x%04x)\n",
-				 chip_ver);
+	for (i = 0; i < ARRAY_SIZE(rtl8365mb_chip_infos); i++) {
+		const struct rtl8365mb_chip_info *ci = &rtl8365mb_chip_infos[i];
+
+		if (ci->chip_id == chip_id && ci->chip_ver == chip_ver) {
+			mb->chip_info = ci;
 			break;
-		default:
-			dev_err(priv->dev, "unrecognized switch version (ver=0x%04x)",
-				chip_ver);
-			return -ENODEV;
 		}
+	}
 
-		priv->num_ports = RTL8365MB_MAX_NUM_PORTS;
-
-		mb->priv = priv;
-		mb->chip_id = chip_id;
-		mb->chip_ver = chip_ver;
-		mb->jam_table = rtl8365mb_init_jam_8365mb_vc;
-		mb->jam_size = ARRAY_SIZE(rtl8365mb_init_jam_8365mb_vc);
-
-		mb->cpu.trap_port = RTL8365MB_MAX_NUM_PORTS;
-		mb->cpu.insert = RTL8365MB_CPU_INSERT_TO_ALL;
-		mb->cpu.position = RTL8365MB_CPU_POS_AFTER_SA;
-		mb->cpu.rx_length = RTL8365MB_CPU_RXLEN_64BYTES;
-		mb->cpu.format = RTL8365MB_CPU_FORMAT_8BYTES;
-
-		break;
-	default:
+	if (!mb->chip_info) {
 		dev_err(priv->dev,
-			"found an unknown Realtek switch (id=0x%04x, ver=0x%04x)\n",
-			chip_id, chip_ver);
+			"unrecognized switch (id=0x%04x, ver=0x%04x)", chip_id,
+			chip_ver);
 		return -ENODEV;
 	}
 
+	dev_info(priv->dev, "found an %s switch\n", mb->chip_info->name);
+
+	priv->num_ports = RTL8365MB_MAX_NUM_PORTS;
+	mb->priv = priv;
+	mb->cpu.trap_port = RTL8365MB_MAX_NUM_PORTS;
+	mb->cpu.insert = RTL8365MB_CPU_INSERT_TO_ALL;
+	mb->cpu.position = RTL8365MB_CPU_POS_AFTER_SA;
+	mb->cpu.rx_length = RTL8365MB_CPU_RXLEN_64BYTES;
+	mb->cpu.format = RTL8365MB_CPU_FORMAT_8BYTES;
+
 	return 0;
 }