[net-next PATCH v2 4/8] net: dsa: realtek: rtl8365mb: add table lookup interface

[Luiz Angelo Daros de Luca <luizluca@gmail.com>]

From: Alvin Šipraga <alsi@bang-olufsen.dk>

Add a generic table lookup interface to centralize access to
the RTL8365MB internal tables.

This interface abstracts the low-level table access logic and
will be used by subsequent commits to implement FDB and VLAN
operations.

Co-developed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
---
 drivers/net/dsa/realtek/Makefile          |   1 +
 drivers/net/dsa/realtek/rtl8365mb_table.c | 255 ++++++++++++++++++++++++++++++
 drivers/net/dsa/realtek/rtl8365mb_table.h | 133 ++++++++++++++++
 3 files changed, 389 insertions(+)

diff --git a/drivers/net/dsa/realtek/Makefile b/drivers/net/dsa/realtek/Makefile
index 3f986e04912f..99654c4c5a3d 100644
--- a/drivers/net/dsa/realtek/Makefile
+++ b/drivers/net/dsa/realtek/Makefile
@@ -17,3 +17,4 @@ rtl8366-objs 				+= rtl8366rb-leds.o
 endif
 obj-$(CONFIG_NET_DSA_REALTEK_RTL8365MB) += rtl8365mb.o
 rtl8365mb-objs := rtl8365mb_main.o \
+		  rtl8365mb_table.o \
diff --git a/drivers/net/dsa/realtek/rtl8365mb_table.c b/drivers/net/dsa/realtek/rtl8365mb_table.c
new file mode 100644
index 000000000000..e706ea2ccb85
--- /dev/null
+++ b/drivers/net/dsa/realtek/rtl8365mb_table.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Look-up table query interface for the rtl8365mb switch family
+ *
+ * Copyright (C) 2022 Alvin Šipraga <alsi@bang-olufsen.dk>
+ */
+
+#include "rtl8365mb_table.h"
+#include <linux/regmap.h>
+
+/* Table access control register */
+#define RTL8365MB_TABLE_CTRL_REG		0x0500
+/* Should be one of rtl8365mb_table enum members */
+#define   RTL8365MB_TABLE_CTRL_TABLE_MASK	GENMASK(2, 0)
+/* Should be one of rtl8365mb_table_op enum members */
+#define   RTL8365MB_TABLE_CTRL_OP_MASK		GENMASK(3, 3)
+/* Should be one of rtl8365mb_table_l2_method enum members */
+#define   RTL8365MB_TABLE_CTRL_METHOD_MASK	GENMASK(7, 4)
+/* NOTE: PORT_MASK is only 4 bit, which suggests that port-based
+ * look-up of the L2 table only works for physical port addresses
+ * 0~4. It could be that the Realtek driver is out-of-date and
+ * actually the mask is something like 0xFF00, but this is
+ * unconfirmed.
+ */
+#define   RTL8365MB_TABLE_CTRL_PORT_MASK	GENMASK(11, 8)
+
+/* Table access address register */
+#define RTL8365MB_TABLE_ACCESS_ADDR_REG		0x0501
+#define   RTL8365MB_TABLE_ADDR_MASK		GENMASK(13, 0)
+
+/* Table status register */
+#define RTL8365MB_TABLE_STATUS_REG			0x0502
+#define   RTL8365MB_TABLE_STATUS_ADDRESS_MASK		GENMASK(10, 0)
+/* set for L3, unset for L2  */
+#define   RTL8365MB_TABLE_STATUS_ADDR_TYPE_MASK		GENMASK(11, 11)
+#define   RTL8365MB_TABLE_STATUS_HIT_STATUS_MASK	GENMASK(12, 12)
+#define   RTL8365MB_TABLE_STATUS_BUSY_FLAG_MASK		GENMASK(13, 13)
+#define   RTL8365MB_TABLE_STATUS_ADDRESS_EXT_MASK	GENMASK(14, 14)
+
+/* Table read/write registers */
+#define RTL8365MB_TABLE_WRITE_BASE			0x0510
+#define RTL8365MB_TABLE_WRITE_REG(_x) \
+		(RTL8365MB_TABLE_WRITE_BASE + (_x))
+#define RTL8365MB_TABLE_READ_BASE			0x0520
+#define RTL8365MB_TABLE_READ_REG(_x) \
+		(RTL8365MB_TABLE_READ_BASE + (_x))
+#define RTL8365MB_TABLE_ENTRY_MAX_SIZE			10
+#define RTL8365MB_TABLE_10TH_DATA_MASK			GENMASK(3, 0)
+#define RTL8365MB_TABLE_WRITE_10TH_REG \
+		RTL8365MB_TABLE_WRITE_REG(RTL8365MB_TABLE_ENTRY_MAX_SIZE - 1)
+
+static int rtl8365mb_table_poll_busy(struct realtek_priv *priv)
+{
+	u32 val;
+
+	return regmap_read_poll_timeout(priv->map_nolock,
+			RTL8365MB_TABLE_STATUS_REG, val,
+			!FIELD_GET(RTL8365MB_TABLE_STATUS_BUSY_FLAG_MASK, val),
+			10, 100);
+}
+
+int rtl8365mb_table_query(struct realtek_priv *priv,
+			  enum rtl8365mb_table table,
+			  enum rtl8365mb_table_op op, u16 *addr,
+			  enum rtl8365mb_table_l2_method method,
+			  u16 port, u16 *data, size_t size)
+{
+	bool addr_as_input = true;
+	bool write_data = false;
+	int ret = 0;
+	u32 cmd;
+	u32 val;
+	u32 hit;
+
+	if (!addr) {
+		dev_err(priv->dev, "%s: addr is NULL\n", __func__);
+		return -EINVAL;
+	}
+
+	if (!data) {
+		dev_err(priv->dev, "%s: data is NULL\n", __func__);
+		return -EINVAL;
+	}
+
+	if (size > RTL8365MB_TABLE_ENTRY_MAX_SIZE) {
+		dev_err(priv->dev, "%s: size too big: %zu\n", __func__, size);
+		return -E2BIG;
+	}
+
+	if (size == 0) {
+		dev_err(priv->dev, "%s: size is 0\n", __func__);
+		return -EINVAL;
+	}
+
+	if (!FIELD_FIT(RTL8365MB_TABLE_CTRL_TABLE_MASK, table)) {
+		dev_err(priv->dev, "%s: table %d does not fit in MASK\n",
+			__func__, table);
+		return -EINVAL;
+	}
+
+	/* Prepare target table and operation (read or write) */
+	cmd = 0;
+	cmd |= FIELD_PREP(RTL8365MB_TABLE_CTRL_TABLE_MASK, table);
+	cmd |= FIELD_PREP(RTL8365MB_TABLE_CTRL_OP_MASK, op);
+	if (op == RTL8365MB_TABLE_OP_READ && table == RTL8365MB_TABLE_L2) {
+		if (!FIELD_FIT(RTL8365MB_TABLE_CTRL_METHOD_MASK, method))
+			return -EINVAL;
+
+		cmd |= FIELD_PREP(RTL8365MB_TABLE_CTRL_METHOD_MASK, method);
+		switch (method) {
+		case RTL8365MB_TABLE_L2_METHOD_MAC:
+			/*
+			 * Method MAC requires as input the same L2 table format
+			 * you'll get as result. However, it might only use mac
+			 * address and FID/VID fields.
+			 */
+			write_data = true;
+
+			/* METHOD_MAC does not use addr as input, but may return
+			 * the matched index.
+			 */
+			addr_as_input = false;
+
+			break;
+		case RTL8365MB_TABLE_L2_METHOD_ADDR:
+		case RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT:
+		case RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_UC:
+		case RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_MC:
+			break;
+		case RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_UC_PORT:
+			if (!FIELD_FIT(RTL8365MB_TABLE_CTRL_PORT_MASK, port))
+				return -EINVAL;
+
+			cmd |= FIELD_PREP(RTL8365MB_TABLE_CTRL_PORT_MASK, port);
+			break;
+		default:
+			return -EINVAL;
+		}
+	} else if (op == RTL8365MB_TABLE_OP_WRITE) {
+		write_data = true;
+
+		/* Writing to L2 does not use addr as input, as the table index
+		 * is derived from key fields.
+		 */
+		if (table == RTL8365MB_TABLE_L2)
+			addr_as_input = false;
+	}
+
+	/* Validate addr only when used as an input */
+	if (addr_as_input) {
+		if (!FIELD_FIT(RTL8365MB_TABLE_ADDR_MASK, *addr)) {
+			dev_err(priv->dev, "%s: addr %u does not fit in MASK\n",
+				__func__, *addr);
+			return -EINVAL;
+		}
+	}
+
+	/* To prevent concurrent access to the look-up tables, take the regmap
+	 * lock manually and access via the map_nolock regmap.
+	 */
+	mutex_lock(&priv->map_lock);
+
+	/* Write entry data if writing to the table (or L2_METHOD_MAC) */
+	if (write_data) {
+		/* bulk write data up to 9th byte */
+		ret = regmap_bulk_write(priv->map_nolock,
+					RTL8365MB_TABLE_WRITE_BASE,
+					data,
+					min_t(size_t, size,
+					      RTL8365MB_TABLE_ENTRY_MAX_SIZE -
+						      1));
+		if (ret)
+			goto out;
+
+		/* 10th register uses only 4 less significant bits */
+		if (size == RTL8365MB_TABLE_ENTRY_MAX_SIZE) {
+			val = FIELD_PREP(RTL8365MB_TABLE_10TH_DATA_MASK,
+					 data[size - 1]);
+			ret = regmap_update_bits(priv->map_nolock,
+						 RTL8365MB_TABLE_WRITE_10TH_REG,
+						 RTL8365MB_TABLE_10TH_DATA_MASK,
+						 val);
+		}
+
+		if (ret)
+			goto out;
+	}
+
+	/* Write address (if needed) */
+	if (addr_as_input) {
+		ret = regmap_write(priv->map_nolock,
+				   RTL8365MB_TABLE_ACCESS_ADDR_REG,
+				   FIELD_PREP(RTL8365MB_TABLE_ADDR_MASK,
+					      *addr));
+		if (ret)
+			goto out;
+	}
+
+	/* Execute */
+	ret = regmap_write(priv->map_nolock, RTL8365MB_TABLE_CTRL_REG, cmd);
+	if (ret)
+		goto out;
+
+	/* Poll for completion */
+	ret = rtl8365mb_table_poll_busy(priv);
+	if (ret)
+		goto out;
+
+	/* For both reads and writes to the L2 table, check status */
+	if (table == RTL8365MB_TABLE_L2) {
+		ret = regmap_read(priv->map_nolock, RTL8365MB_TABLE_STATUS_REG,
+				  &val);
+		if (ret)
+			goto out;
+
+		/* Did the query find an entry? */
+		hit = FIELD_GET(RTL8365MB_TABLE_STATUS_HIT_STATUS_MASK, val);
+		if (!hit) {
+			ret = -ENOENT;
+			goto out;
+		}
+
+		/* If so, extract the address */
+		*addr = 0;
+		*addr |= FIELD_GET(RTL8365MB_TABLE_STATUS_ADDRESS_MASK, val);
+		*addr |= FIELD_GET(RTL8365MB_TABLE_STATUS_ADDRESS_EXT_MASK, val)
+			 << 11;
+		/* only set if it is a L3 address */
+		*addr |= FIELD_GET(RTL8365MB_TABLE_STATUS_ADDR_TYPE_MASK, val)
+			 << 12;
+	}
+
+	/* Finally, get the table entry if we were reading */
+	if (op == RTL8365MB_TABLE_OP_READ) {
+		ret = regmap_bulk_read(priv->map_nolock,
+				       RTL8365MB_TABLE_READ_BASE,
+				       data, size);
+
+		/* For the biggest table entries, the uppermost table
+		 * entry register has space for only one nibble. Mask
+		 * out the remainder bits. Empirically I saw nothing
+		 * wrong with omitting this mask, but it may prevent
+		 * unwanted behaviour. FYI.
+		 */
+		if (size == RTL8365MB_TABLE_ENTRY_MAX_SIZE) {
+			val = FIELD_GET(RTL8365MB_TABLE_10TH_DATA_MASK,
+					data[size - 1]);
+			data[size - 1] = val;
+		}
+	}
+
+out:
+	mutex_unlock(&priv->map_lock);
+
+	return ret;
+}
diff --git a/drivers/net/dsa/realtek/rtl8365mb_table.h b/drivers/net/dsa/realtek/rtl8365mb_table.h
new file mode 100644
index 000000000000..0b1a89bd81f1
--- /dev/null
+++ b/drivers/net/dsa/realtek/rtl8365mb_table.h
@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Look-up table query interface for the rtl8365mb switch family
+ *
+ * Copyright (C) 2022 Alvin Šipraga <alsi@bang-olufsen.dk>
+ */
+
+#ifndef _REALTEK_RTL8365MB_TABLE_H
+#define _REALTEK_RTL8365MB_TABLE_H
+
+#include <linux/if_ether.h>
+#include <linux/types.h>
+
+#include "realtek.h"
+
+/**
+ * struct rtl8365mb_table - available switch tables
+ *
+ * @RTL8365MB_TABLE_ACL_RULE - ACL rules
+ * @RTL8365MB_TABLE_ACL_ACTION - ACL actions
+ * @RTL8365MB_TABLE_CVLAN - VLAN4k configurations
+ * @RTL8365MB_TABLE_L2 - filtering database (2K hash table)
+ * @RTL8365MB_TABLE_IGMP_GROUP - IGMP group database (readonly)
+ *
+ * NOTE: Don't change the enum values. They must concur with the field
+ * described by @RTL8365MB_TABLE_CTRL_TABLE_MASK.
+ */
+enum rtl8365mb_table {
+	RTL8365MB_TABLE_ACL_RULE = 1,
+	RTL8365MB_TABLE_ACL_ACTION = 2,
+	RTL8365MB_TABLE_CVLAN = 3,
+	RTL8365MB_TABLE_L2 = 4,
+	RTL8365MB_TABLE_IGMP_GROUP = 5,
+};
+
+/**
+ * enum rtl8365mb_table_op - table query operation
+ *
+ * @RTL8365MB_TABLE_OP_READ: read an entry from the target table
+ * @RTL8365MB_TABLE_OP_WRITE: write an entry to the target table
+ *
+ * NOTE: Don't change the enum values. They must concur with the field
+ * described by @RTL8365MB_TABLE_CTRL_OP_MASK.
+ */
+enum rtl8365mb_table_op {
+	RTL8365MB_TABLE_OP_READ = 0,
+	RTL8365MB_TABLE_OP_WRITE = 1,
+};
+
+/**
+ * enum rtl8365mb_table_l2_method - look-up method for read queries of L2 table
+ *
+ * @RTL8365MB_TABLE_L2_METHOD_MAC: look-up by source MAC address and FID (or
+ *   VID)
+ * @RTL8365MB_TABLE_L2_METHOD_ADDR: look-up by entry address
+ * @RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT: look-up next entry starting from the
+ *   supplied address
+ * @RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_UC: same as ADDR_NEXT but search only
+ *   unicast addresses
+ * @RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_MC: same as ADDR_NEXT but search only
+ *   multicast addresses
+ * @RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_UC_PORT: same as ADDR_NEXT_UC but
+ *   search only entries with matching source port
+ *
+ * NOTE: Don't change the enum values. They must concur with the field
+ * described by @RTL8365MB_TABLE_CTRL_METHOD_MASK
+ */
+enum rtl8365mb_table_l2_method {
+	RTL8365MB_TABLE_L2_METHOD_MAC = 0,
+	RTL8365MB_TABLE_L2_METHOD_ADDR = 1,
+	RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT = 2,
+	RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_UC = 3,
+	RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_MC = 4,
+	/*
+	 * RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_MC_L3 = 5,
+	 * RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_MC_L2L3 = 6,
+	 */
+	RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_UC_PORT = 7,
+};
+
+/**
+ * rtl8365mb_table_query() - read from or write to a switch table
+ * @priv: driver context
+ * @table: target table, see &enum rtl8365mb_table
+ * @op: read or write operation, see &enum rtl8365mb_table_op
+ * @addr: table address. For indexed tables, this selects the entry to access.
+ *        For L2 read queries, it is ignored as input for MAC-based lookup
+ *        methods and used as input for address-based lookup methods. On
+ *        successful L2 queries, it is updated with the matched entry address.
+ * @method: L2 table lookup method, see &enum rtl8365mb_table_l2_method.
+ *	    Ignored for non-L2 tables.
+ * @port: for L2 read queries using method
+ *        %RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_UC_PORT, restrict the search
+ *        to entries associated with this source port. Ignored otherwise.
+ * @data: data buffer used to read from or write to the table. For L2 MAC
+ *        lookups, this buffer provides the lookup key and receives the
+ *        matched entry contents on success.
+ * @size: size of @data in 16-bit words
+ *
+ * This function provides unified access to the internal tables of the switch.
+ * All tables except the L2 table are simple indexed tables, where @addr
+ * selects the entry and @op determines whether the access is a read or a
+ * write operation.
+ *
+ * The L2 table is a hash table and supports multiple lookup methods. For
+ * %RTL8365MB_TABLE_L2_METHOD_MAC, an entry is searched based on the MAC
+ * address and FID/VID fields provided in @data, using the same format as
+ * an L2 table entry. Address-based methods either read a specific entry
+ * (%RTL8365MB_TABLE_L2_METHOD_ADDR) or iterate over valid entries starting
+ * from @addr (%RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT and variants). When using
+ * %RTL8365MB_TABLE_L2_METHOD_ADDR_NEXT_UC_PORT, only entries associated with
+ * the specified @port are considered.
+ *
+ * On successful L2 lookups, @addr is updated with the matched table address
+ * and @data contains the corresponding table entry. If no matching entry
+ * is found, -ENOENT is returned.
+ *
+ * The contents of @data are used as input when writing to tables or when
+ * specifying the lookup key for L2 MAC searches, and as output for all
+ * successful read operations. If an error occurs, the contents of @addr
+ * and @data are undefined.
+ *
+ * @size must match the size of the target table entry, expressed in 16-bit
+ * words. This function only validates that it is non-zero and fits in the
+ * available register space.
+ *
+ */
+int rtl8365mb_table_query(struct realtek_priv *priv,
+			  enum rtl8365mb_table table,
+			  enum rtl8365mb_table_op op, u16 *addr,
+			  enum rtl8365mb_table_l2_method method,
+			  u16 port, u16 *data, size_t size);
+
+#endif /* _REALTEK_RTL8365MB_TABLE_H */

-- 
2.53.0