net: dsa: realtek-smi: Add Realtek SMI driver

This adds a driver core for the Realtek SMI chips and a
subdriver for the RTL8366RB. I just added this chip simply
because it is all I can test.

The code is a massaged variant of the code that has been
sitting out-of-tree in OpenWRT for years in the absence of
a proper switch subsystem. This creates a DSA driver for it.
I have tried to credit the original authors wherever
possible.

The main changes I've done from the OpenWRT code:

- Added an IRQ chip inside the RTL8366RB switch to demux and
  handle the line state IRQs.

- Distributed the phy handling out to the PHY driver.

- Added some RTL8366RB code that was missing in the driver at
  the time, such as setting up "green ethernet" with a funny
  jam table and forcing MAC5 (the CPU port) into 1 GBit.

- Select jam table and add the default jam table from the
  vendor driver, also for ASIC "version 0" if need be.

- Do not store jam tables in the device tree, store them
  in the driver.

- Pick in the "initvals" jam tables from OpenWRT's driver
  and make those get selected per compatible for the
  whole system. It's apparently about electrical settings
  for this system and whatnot, not really configuration
  from device tree.

- Implemented LED control: beware of bugs because there are
  no LEDs on the device I am using!

We do not implement custom DSA tags. This is explained in
a comment in the driver as well: this "tagging protocol" is
not simply a few extra bytes tagged on to the ethernet
frame as DSA is used to. Instead, enabling the CPU tags
will make the switch start talking Realtek RRCP internally.
For example a simple ping will make this kind of packets
appear inside the switch:

0000   ff ff ff ff ff ff bc ae c5 6b a8 3d 88 99 a2 00
0010   08 06 00 01 08 00 06 04 00 01 bc ae c5 6b a8 3d
0020   a9 fe 01 01 00 00 00 00 00 00 a9 fe 01 02 00 00
0030   00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

As you can see a custom "8899" tagged packet using the
protocol 0xa2. Norm RRCP appears to always have this
protocol set to 0x01 according to OpenRRCP. You can also
see that this is not a ping packet at all, instead the
switch is starting to talk network management issues
with the CPU port.

So for now custom "tagging" is disabled.

This was tested on the D-Link DIR-685 with initramfs and
OpenWRT userspaces and works fine on all the LAN ports
(lan0 .. lan3). The WAN port is yet not working.

Cc: Antti Seppälä <a.seppala@gmail.com>
Cc: Roman Yeryomin <roman@advem.lv>
Cc: Colin Leitner <colin.leitner@googlemail.com>
Cc: Gabor Juhos <juhosg@openwrt.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -12063,6 +12063,13 @@ S:	Maintained
 F:	sound/soc/codecs/rt*
 F:	include/sound/rt*.h
 
+REALTEK RTL83xx SMI DSA ROUTER CHIPS
+M:	Linus Walleij <linus.walleij@linaro.org>
+S:	Maintained
+F:	Documentation/devicetree/bindings/net/dsa/realtek-smi.txt
+F:	drivers/net/dsa/realtek-smi*
+F:	drivers/net/dsa/rtl83*
+
 REGISTER MAP ABSTRACTION
 M:	Mark Brown <broonie@kernel.org>
 L:	linux-kernel@vger.kernel.org

drivers/net/dsa/Kconfig

@@ -52,6 +52,17 @@ config NET_DSA_QCA8K
 	  This enables support for the Qualcomm Atheros QCA8K Ethernet
 	  switch chips.
 
+config NET_DSA_REALTEK_SMI
+	tristate "Realtek SMI Ethernet switch family support"
+	depends on NET_DSA
+	select FIXED_PHY
+	select IRQ_DOMAIN
+	select REALTEK_PHY
+	select REGMAP
+	---help---
+	  This enables support for the Realtek SMI-based switch
+	  chips, currently only RTL8366RB.
+
 config NET_DSA_SMSC_LAN9303
 	tristate
 	select NET_DSA_TAG_LAN9303

drivers/net/dsa/Makefile

@@ -8,6 +8,8 @@ endif
 obj-$(CONFIG_NET_DSA_MT7530)	+= mt7530.o
 obj-$(CONFIG_NET_DSA_MV88E6060) += mv88e6060.o
 obj-$(CONFIG_NET_DSA_QCA8K)	+= qca8k.o
+obj-$(CONFIG_NET_DSA_REALTEK_SMI) += realtek.o
+realtek-objs			:= realtek-smi.o rtl8366.o rtl8366rb.o
 obj-$(CONFIG_NET_DSA_SMSC_LAN9303) += lan9303-core.o
 obj-$(CONFIG_NET_DSA_SMSC_LAN9303_I2C) += lan9303_i2c.o
 obj-$(CONFIG_NET_DSA_SMSC_LAN9303_MDIO) += lan9303_mdio.o

drivers/net/dsa/realtek-smi.h

+/* SPDX-License-Identifier: GPL-2.0+ */
+/* Realtek SMI interface driver defines
+ *
+ * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
+ * Copyright (C) 2009-2010 Gabor Juhos <juhosg@openwrt.org>
+ */
+
+#ifndef _REALTEK_SMI_H
+#define _REALTEK_SMI_H
+
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/gpio/consumer.h>
+#include <net/dsa.h>
+
+struct realtek_smi_ops;
+struct dentry;
+struct inode;
+struct file;
+
+struct rtl8366_mib_counter {
+	unsigned int	base;
+	unsigned int	offset;
+	unsigned int	length;
+	const char	*name;
+};
+
+struct rtl8366_vlan_mc {
+	u16	vid;
+	u16	untag;
+	u16	member;
+	u8	fid;
+	u8	priority;
+};
+
+struct rtl8366_vlan_4k {
+	u16	vid;
+	u16	untag;
+	u16	member;
+	u8	fid;
+};
+
+struct realtek_smi {
+	struct device		*dev;
+	struct gpio_desc	*reset;
+	struct gpio_desc	*mdc;
+	struct gpio_desc	*mdio;
+	struct regmap		*map;
+	struct mii_bus		*slave_mii_bus;
+
+	unsigned int		clk_delay;
+	u8			cmd_read;
+	u8			cmd_write;
+	spinlock_t		lock; /* Locks around command writes */
+	struct dsa_switch	*ds;
+	struct irq_domain	*irqdomain;
+	bool			leds_disabled;
+
+	unsigned int		cpu_port;
+	unsigned int		num_ports;
+	unsigned int		num_vlan_mc;
+	unsigned int		num_mib_counters;
+	struct rtl8366_mib_counter *mib_counters;
+
+	const struct realtek_smi_ops *ops;
+
+	int			vlan_enabled;
+	int			vlan4k_enabled;
+
+	char			buf[4096];
+};
+
+/**
+ * struct realtek_smi_ops - vtable for the per-SMI-chiptype operations
+ * @detect: detects the chiptype
+ */
+struct realtek_smi_ops {
+	int	(*detect)(struct realtek_smi *smi);
+	int	(*reset_chip)(struct realtek_smi *smi);
+	int	(*setup)(struct realtek_smi *smi);
+	void	(*cleanup)(struct realtek_smi *smi);
+	int	(*get_mib_counter)(struct realtek_smi *smi,
+				   int port,
+				   struct rtl8366_mib_counter *mib,
+				   u64 *mibvalue);
+	int	(*get_vlan_mc)(struct realtek_smi *smi, u32 index,
+			       struct rtl8366_vlan_mc *vlanmc);
+	int	(*set_vlan_mc)(struct realtek_smi *smi, u32 index,
+			       const struct rtl8366_vlan_mc *vlanmc);
+	int	(*get_vlan_4k)(struct realtek_smi *smi, u32 vid,
+			       struct rtl8366_vlan_4k *vlan4k);
+	int	(*set_vlan_4k)(struct realtek_smi *smi,
+			       const struct rtl8366_vlan_4k *vlan4k);
+	int	(*get_mc_index)(struct realtek_smi *smi, int port, int *val);
+	int	(*set_mc_index)(struct realtek_smi *smi, int port, int index);
+	bool	(*is_vlan_valid)(struct realtek_smi *smi, unsigned int vlan);
+	int	(*enable_vlan)(struct realtek_smi *smi, bool enable);
+	int	(*enable_vlan4k)(struct realtek_smi *smi, bool enable);
+	int	(*enable_port)(struct realtek_smi *smi, int port, bool enable);
+	int	(*phy_read)(struct realtek_smi *smi, int phy, int regnum);
+	int	(*phy_write)(struct realtek_smi *smi, int phy, int regnum,
+			     u16 val);
+};
+
+struct realtek_smi_variant {
+	const struct dsa_switch_ops *ds_ops;
+	const struct realtek_smi_ops *ops;
+	unsigned int clk_delay;
+	u8 cmd_read;
+	u8 cmd_write;
+};
+
+/* SMI core calls */
+int realtek_smi_write_reg_noack(struct realtek_smi *smi, u32 addr,
+				u32 data);
+int realtek_smi_setup_mdio(struct realtek_smi *smi);
+
+/* RTL8366 library helpers */
+int rtl8366_mc_is_used(struct realtek_smi *smi, int mc_index, int *used);
+int rtl8366_set_vlan(struct realtek_smi *smi, int vid, u32 member,
+		     u32 untag, u32 fid);
+int rtl8366_get_pvid(struct realtek_smi *smi, int port, int *val);
+int rtl8366_set_pvid(struct realtek_smi *smi, unsigned int port,
+		     unsigned int vid);
+int rtl8366_enable_vlan4k(struct realtek_smi *smi, bool enable);
+int rtl8366_enable_vlan(struct realtek_smi *smi, bool enable);
+int rtl8366_reset_vlan(struct realtek_smi *smi);
+int rtl8366_init_vlan(struct realtek_smi *smi);
+int rtl8366_vlan_filtering(struct dsa_switch *ds, int port,
+			   bool vlan_filtering);
+int rtl8366_vlan_prepare(struct dsa_switch *ds, int port,
+			 const struct switchdev_obj_port_vlan *vlan);
+void rtl8366_vlan_add(struct dsa_switch *ds, int port,
+		      const struct switchdev_obj_port_vlan *vlan);
+int rtl8366_vlan_del(struct dsa_switch *ds, int port,
+		     const struct switchdev_obj_port_vlan *vlan);
+void rtl8366_get_strings(struct dsa_switch *ds, int port, u32 stringset,
+			 uint8_t *data);
+int rtl8366_get_sset_count(struct dsa_switch *ds, int port, int sset);
+void rtl8366_get_ethtool_stats(struct dsa_switch *ds, int port, uint64_t *data);
+
+extern const struct realtek_smi_variant rtl8366rb_variant;
+
+#endif /*  _REALTEK_SMI_H */