[PATCH net-next v13 10/11] net: mdio: realtek-rtl9300: Add support for RTL839x

[Markus Stockhausen <markus.stockhausen@gmx.de>]

The MDIO driver has been prepared for multiple device support. Add all
required bits for the RTL839x (aka cypress) series. This is straightforward
but some things are worth mentioning.

- The device has a lot in common with the RTL931x series. It has 8192
  (Realtek) pages and 7 MMIO registers.
- There are two SMI buses for 1G PHYs. Neither the bus nor address map
  registers exist.
- The hardware has not much to configure. So the setup_controller()
  function is not needed.
- The bit specific registers (polling & port_mask) are 2x32 bit wide. The
  ports 0..31 got to <reg> and the ports 32..51 go to <reg+4>.
- C22 read/write functions must be called with PARK_PAGE = 0. Keep code
  clean and avoid setting it to zero, matching the behavior of the RTL9310
  logic.
- As per SDK the broadcast register allows to write to multiple ports
  at the same time. Unlike RTL9310 where this is filled with a bit mask
  for the current port RTL8390 does not use it for normal reads/writes.
  It is simply set to 0 like the SDK does.
- The SDK fills the EXT_PAGE register with 0x1ff for C22 access and with
  0x0 for C45 access. The reason for this is currently unknown and a
  meaningful name can not be given. Align the driver coding with the
  RTL9300_PHY_CTRL_PARK_PAGE settings and simply fill the hardcoded value.

As per the SDK the PHYs on a RTl83xx bus are mainly C22 driven. The
polling unit works in C22 mode and the devicetree usually does not
make use of the ethernet-phy-ieee802.3-c45 flag. Nevertheless there are
some PHY MMD registers (e.g. EEE) that might be of interest for the
future development of the hardware. Until that is really needed keep
the C45 read/write helpers out of the driver.

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
---
 drivers/net/mdio/mdio-realtek-rtl9300.c | 73 +++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/drivers/net/mdio/mdio-realtek-rtl9300.c b/drivers/net/mdio/mdio-realtek-rtl9300.c
index 6e37a3f52b5e..7792cdbedda4 100644
--- a/drivers/net/mdio/mdio-realtek-rtl9300.c
+++ b/drivers/net/mdio/mdio-realtek-rtl9300.c
@@ -147,6 +147,28 @@
 #define RTL8380_SMI_POLL_CTRL			0xa17c
 #define RTL8380_SMI_PORT0_5_ADDR_CTRL		0xa1c8
 
+#define RTL8390_NUM_BUSES			2
+#define RTL8390_NUM_PAGES			8192
+#define RTL8390_NUM_PORTS			52
+#define RTL8390_BCAST_PHYID_CTRL		0x03ec
+#define RTL8390_PHYREG_ACCESS_CTRL		0x03dc
+#define   RTL8390_PHY_CTRL_REG_ADDR		GENMASK(9, 5)
+#define   RTL8390_PHY_CTRL_MAIN_PAGE		GENMASK(22, 10)
+#define   RTL8390_PHY_CTRL_FAIL			BIT(1)
+#define   RTL8390_PHY_CTRL_WRITE		BIT(3)
+#define   RTL8390_PHY_CTRL_READ			0
+#define   RTL8390_PHY_CTRL_TYPE_C45		BIT(2)
+#define   RTL8390_PHY_CTRL_TYPE_C22		0
+#define RTL8390_PHYREG_CTRL			0x03e0
+#define   RTL8390_PHY_CTRL_EXT_PAGE		GENMASK(8, 0)
+#define RTL8390_PHYREG_DATA_CTRL		0x03f0
+#define   RTL8390_PHY_CTRL_INDATA		GENMASK(31, 16)
+#define   RTL8390_PHY_CTRL_DATA			GENMASK(15, 0)
+#define RTL8390_PHYREG_MMD_CTRL			0x03f4
+#define RTL8390_PHYREG_PORT_CTRL_LOW		0x03e4
+#define RTL8390_PHYREG_PORT_CTRL_HIGH		0x03e8
+#define RTL8390_SMI_PORT_POLLING_CTRL		0x03fc
+
 #define RTL9300_NUM_BUSES			4
 #define RTL9300_NUM_PAGES			4096
 #define RTL9300_NUM_PORTS			28
@@ -402,6 +424,35 @@ static int otto_emdio_8380_write_c22(struct mii_bus *bus, int port, int regnum,
 	return otto_emdio_write_cmd(bus, RTL8380_PHY_CTRL_TYPE_C22, &cmd_data);
 }
 
+static int otto_emdio_8390_read_c22(struct mii_bus *bus, int port, int regnum, u32 *value)
+{
+	struct otto_emdio_priv *priv = otto_emdio_bus_to_priv(bus);
+	struct otto_emdio_cmd_regs cmd_data = {
+		.c22_data	= FIELD_PREP(RTL8390_PHY_CTRL_REG_ADDR, regnum) |
+				  FIELD_PREP(RTL8390_PHY_CTRL_MAIN_PAGE, priv->page[port]),
+		.ext_page	= FIELD_PREP(RTL8390_PHY_CTRL_EXT_PAGE, 0x1ff),
+		.io_data	= FIELD_PREP(RTL8390_PHY_CTRL_INDATA, port),
+	};
+
+	return otto_emdio_read_cmd(bus, RTL8390_PHY_CTRL_TYPE_C22, &cmd_data,
+				   RTL8390_PHY_CTRL_DATA, value);
+}
+
+static int otto_emdio_8390_write_c22(struct mii_bus *bus, int port, int regnum, u16 value)
+{
+	struct otto_emdio_priv *priv = otto_emdio_bus_to_priv(bus);
+	struct otto_emdio_cmd_regs cmd_data = {
+		.c22_data	= FIELD_PREP(RTL8390_PHY_CTRL_REG_ADDR, regnum) |
+				  FIELD_PREP(RTL8390_PHY_CTRL_MAIN_PAGE, priv->page[port]),
+		.ext_page	= FIELD_PREP(RTL8390_PHY_CTRL_EXT_PAGE, 0x1ff),
+		.io_data	= FIELD_PREP(RTL8390_PHY_CTRL_INDATA, value),
+		.port_mask_high	= (u32)(BIT_ULL(port) >> 32),
+		.port_mask_low	= (u32)(BIT_ULL(port)),
+	};
+
+	return otto_emdio_write_cmd(bus, RTL8390_PHY_CTRL_TYPE_C22, &cmd_data);
+}
+
 static int otto_emdio_9300_read_c22(struct mii_bus *bus, int port, int regnum, u32 *value)
 {
 	struct otto_emdio_priv *priv = otto_emdio_bus_to_priv(bus);
@@ -947,6 +998,27 @@ static const struct otto_emdio_info otto_emdio_8380_info = {
 	.write_c22 = otto_emdio_8380_write_c22,
 };
 
+static const struct otto_emdio_info otto_emdio_8390_info = {
+	.cmd_fail = RTL8390_PHY_CTRL_FAIL,
+	.cmd_read = RTL8390_PHY_CTRL_READ,
+	.cmd_write = RTL8390_PHY_CTRL_WRITE,
+	.cmd_regs = {
+		.broadcast = RTL8390_BCAST_PHYID_CTRL,
+		.c22_data = RTL8390_PHYREG_ACCESS_CTRL,
+		.c45_data = RTL8390_PHYREG_MMD_CTRL,
+		.ext_page = RTL8390_PHYREG_CTRL,
+		.io_data = RTL8390_PHYREG_DATA_CTRL,
+		.port_mask_low = RTL8390_PHYREG_PORT_CTRL_LOW,
+		.port_mask_high = RTL8390_PHYREG_PORT_CTRL_HIGH,
+	},
+	.num_buses = RTL8390_NUM_BUSES,
+	.num_pages = RTL8390_NUM_PAGES,
+	.num_ports = RTL8390_NUM_PORTS,
+	.poll_ctrl = RTL8390_SMI_PORT_POLLING_CTRL,
+	.read_c22 = otto_emdio_8390_read_c22,
+	.write_c22 = otto_emdio_8390_write_c22,
+};
+
 static const struct otto_emdio_info otto_emdio_9300_info = {
 	.addr_map_base = RTL9300_SMI_PORT0_5_ADDR_CTRL,
 	.bus_map_base = RTL9300_SMI_PORT0_15_POLLING_SEL,
@@ -998,6 +1070,7 @@ static const struct otto_emdio_info otto_emdio_9310_info = {
 
 static const struct of_device_id otto_emdio_ids[] = {
 	{ .compatible = "realtek,rtl8380-mdio", .data = &otto_emdio_8380_info },
+	{ .compatible = "realtek,rtl8391-mdio", .data = &otto_emdio_8390_info },
 	{ .compatible = "realtek,rtl9301-mdio", .data = &otto_emdio_9300_info },
 	{ .compatible = "realtek,rtl9311-mdio", .data = &otto_emdio_9310_info },
 	{}
-- 
2.55.0