Some multigig SFPs from RollBall and Hilink do not expose functional
MDIO access to the internal PHY of the SFP via I2C address 0x56
(although there seems to be read-only clause 22 access on this address).
Instead these SFPs PHY can be accessed via I2C via the SFP Enhanced
Digital Diagnostic Interface - I2C address 0x51.
This extends the mdio-i2c driver so that when SFP PHY address 17 is used
(which in mdio-i2c terms corresponds to I2C address 0x51), then this
different protocol is used for MDIO access.
Signed-off-by: Marek Behún <ka...@kernel.org>
---
drivers/net/phy/mdio-i2c.c | 196 +++++++++++++++++++++++++++++++++++--
1 file changed, 186 insertions(+), 10 deletions(-)
diff --git a/drivers/net/phy/mdio-i2c.c b/drivers/net/phy/mdio-i2c.c
index 0746e2cc39ae..1468f50e35a9 100644
--- a/drivers/net/phy/mdio-i2c.c
+++ b/drivers/net/phy/mdio-i2c.c
@@ -3,6 +3,7 @@
* MDIO I2C bridge
*
* Copyright (C) 2015-2016 Russell King
+ * Copyright (C) 2020 Marek Behun
*
* Network PHYs can appear on I2C buses when they are part of SFP module.
* This driver exposes these PHYs to the networking PHY code, allowing
@@ -17,11 +18,17 @@
/*
* I2C bus addresses 0x50 and 0x51 are normally an EEPROM, which is
* specified to be present in SFP modules. These correspond with PHY
- * addresses 16 and 17. Disallow access to these "phy" addresses.
+ * addresses 16 and 17. Disallow access to 0x50 "phy" address.
+ * Use RollBall protocol when accessing via the 0x51 address.
*/
static bool i2c_mii_valid_phy_id(int phy_id)
{
- return phy_id != 0x10 && phy_id != 0x11;
+ return phy_id != 0x10;
+}
+
+static bool i2c_mii_rollball_phy_id(int phy_id)
+{
+ return phy_id == 0x11;
}
static unsigned int i2c_mii_phy_addr(int phy_id)
@@ -29,16 +36,13 @@ static unsigned int i2c_mii_phy_addr(int phy_id)
return phy_id + 0x40;
}
-static int i2c_mii_read(struct mii_bus *bus, int phy_id, int reg)
+static int i2c_mii_read_default(struct mii_bus *bus, int phy_id, int reg)
{
struct i2c_adapter *i2c = bus->priv;
struct i2c_msg msgs[2];
u8 addr[3], data[2], *p;
int bus_addr, ret;
- if (!i2c_mii_valid_phy_id(phy_id))
- return 0xffff;
-
p = addr;
if (reg & MII_ADDR_C45) {
*p++ = 0x20 | ((reg >> 16) & 31);
@@ -63,16 +67,13 @@ static int i2c_mii_read(struct mii_bus *bus, int phy_id,
int reg)
return data[0] << 8 | data[1];
}
-static int i2c_mii_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
+static int i2c_mii_write_default(struct mii_bus *bus, int phy_id, int reg, u16
val)
{
struct i2c_adapter *i2c = bus->priv;
struct i2c_msg msg;
int ret;
u8 data[5], *p;
- if (!i2c_mii_valid_phy_id(phy_id))
- return 0;
-
p = data;
if (reg & MII_ADDR_C45) {
*p++ = (reg >> 16) & 31;
@@ -92,6 +93,181 @@ static int i2c_mii_write(struct mii_bus *bus, int phy_id,
int reg, u16 val)
return ret < 0 ? ret : 0;
}
+/* RollBall SFPs do not access internal PHY via I2C address 0x56, but
+ * instead via address 0x51, when SFP page is set to 0x03 and password to
+ * 0xffffffff:
+ *
+ * address size contents description
+ * ------- ---- -------- -----------
+ * 0x80 1 CMD 0x01/0x02/0x04 for write/read/done
+ * 0x81 1 DEV Clause 45 device
+ * 0x82 2 REG Clause 45 register
+ * 0x84 2 VAL Register value
+ */
+#define ROLLBALL_CMD_ADDR 0x80
+#define ROLLBALL_DATA_ADDR 0x81
+
+#define ROLLBALL_CMD_WRITE 0x01
+#define ROLLBALL_CMD_READ 0x02
+#define ROLLBALL_CMD_DONE 0x04
+
+static int i2c_rollball_mii_poll(struct mii_bus *bus, int bus_addr, u8 *buf,
size_t len)
+{
+ struct i2c_adapter *i2c = bus->priv;
+ struct i2c_msg msgs[2];
+ u8 buf0[2], *res;
+ int i, ret;
+
+ buf0[0] = ROLLBALL_CMD_ADDR;
+
+ msgs[0].addr = bus_addr;
+ msgs[0].flags = 0;
+ msgs[0].len = 1;
+ msgs[0].buf = &buf0[0];
+
+ res = buf ? buf : &buf0[1];
+
+ msgs[1].addr = bus_addr;
+ msgs[1].flags = I2C_M_RD;
+ msgs[1].len = buf ? len : 1;
+ msgs[1].buf = res;
+
+ /* By experiment it takes up to 70 ms to access a register for these
SFPs. Sleep 20ms
+ * between iteratios and try 10 times.
+ */
+ i = 10;
+ do {
+ msleep(20);
+
+ ret = i2c_transfer(i2c, msgs, ARRAY_SIZE(msgs));
+ if (ret < 0)
+ return ret;
+ else if (ret != ARRAY_SIZE(msgs))
+ return -EIO;
+
+ if (*res == ROLLBALL_CMD_DONE)
+ return 0;
+ } while (i-- > 0);
+
+ dev_dbg(&bus->dev, "poll timed out\n");
+
+ return -ETIMEDOUT;
+}
+
+static int i2c_rollball_mii_cmd(struct mii_bus *bus, int bus_addr, u8 cmd, u8
*data, size_t len)
+{
+ struct i2c_adapter *i2c = bus->priv;
+ struct i2c_msg msgs[2];
+ u8 cmdbuf[2];
+ int ret;
+
+ msgs[0].addr = bus_addr;
+ msgs[0].flags = 0;
+ msgs[0].len = len;
+ msgs[0].buf = data;
+
+ cmdbuf[0] = ROLLBALL_CMD_ADDR;
+ cmdbuf[1] = cmd;
+
+ msgs[1].addr = bus_addr;
+ msgs[1].flags = 0;
+ msgs[1].len = sizeof(cmdbuf);
+ msgs[1].buf = cmdbuf;
+
+ ret = i2c_transfer(i2c, msgs, 2);
+ if (ret < 0)
+ return ret;
+
+ return ret == ARRAY_SIZE(msgs) ? 0 : -EIO;
+}
+
+static int i2c_mii_read_rollball(struct mii_bus *bus, int phy_id, int reg)
+{
+ u8 buf[4], res[6];
+ int bus_addr, ret;
+ u16 val;
+
+ if (!(reg & MII_ADDR_C45))
+ return -EOPNOTSUPP;
+
+ buf[0] = ROLLBALL_DATA_ADDR;
+ buf[1] = (reg >> 16) & 0x1f;
+ buf[2] = (reg >> 8) & 0xff;
+ buf[3] = reg & 0xff;
+
+ bus_addr = i2c_mii_phy_addr(phy_id);
+
+ ret = i2c_rollball_mii_cmd(bus, bus_addr, ROLLBALL_CMD_READ, buf,
sizeof(buf));
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_rollball_mii_poll(bus, bus_addr, res, sizeof(res));
+ if (ret == -ETIMEDOUT)
+ return 0xffff;
+ else if (ret < 0)
+ return ret;
+
+ val = res[4];
+ val <<= 8;
+ val |= res[5];
+
+ dev_dbg(&bus->dev, "read reg %02x:%04x = %04x\n", (reg >> 16) & 0x1f,
reg & 0xffff, val);
+
+ return val;
+}
+
+static int i2c_mii_write_rollball(struct mii_bus *bus, int phy_id, int reg,
u16 val)
+{
+ int bus_addr, ret;
+ u8 buf[6];
+
+ if (!(reg & MII_ADDR_C45))
+ return -EOPNOTSUPP;
+
+ buf[0] = ROLLBALL_DATA_ADDR;
+ buf[1] = (reg >> 16) & 0x1f;
+ buf[2] = (reg >> 8) & 0xff;
+ buf[3] = reg & 0xff;
+ buf[4] = val >> 8;
+ buf[5] = val & 0xff;
+
+ bus_addr = i2c_mii_phy_addr(phy_id);
+
+ ret = i2c_rollball_mii_cmd(bus, bus_addr, ROLLBALL_CMD_WRITE, buf,
sizeof(buf));
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_rollball_mii_poll(bus, bus_addr, NULL, 0);
+ if (ret < 0)
+ return ret;
+
+ dev_dbg(&bus->dev, "write reg %02x:%04x = %04x\n", (reg >> 16) & 0x1f,
reg & 0xffff, val);
+
+ return 0;
+}
+
+static int i2c_mii_read(struct mii_bus *bus, int phy_id, int reg)
+{
+ if (!i2c_mii_valid_phy_id(phy_id))
+ return 0xffff;
+
+ if (i2c_mii_rollball_phy_id(phy_id))
+ return i2c_mii_read_rollball(bus, phy_id, reg);
+ else
+ return i2c_mii_read_default(bus, phy_id, reg);
+}
+
+static int i2c_mii_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
+{
+ if (!i2c_mii_valid_phy_id(phy_id))
+ return 0;
+
+ if (i2c_mii_rollball_phy_id(phy_id))
+ return i2c_mii_write_rollball(bus, phy_id, reg, val);
+ else
+ return i2c_mii_write_default(bus, phy_id, reg, val);
+}
+
struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c)
{
struct mii_bus *mii;
--
2.26.2
