Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 417 insertions, 0 deletions

diff --git a/drivers/net/mdio/mdio-i2c.c b/drivers/net/mdio/mdio-i2c.c
new file mode 100644
index 000000000..bf8bf5e20
--- /dev/null
+++ b/drivers/net/mdio/mdio-i2c.c
@@ -0,0 +1,417 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * MDIO I2C bridge
+ *
+ * Copyright (C) 2015-2016 Russell King
+ * Copyright (C) 2021 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
+ * our PHY drivers access to these PHYs, and so allowing configuration
+ * of their settings.
+ */
+#include <linux/i2c.h>
+#include <linux/mdio/mdio-i2c.h>
+#include <linux/phy.h>
+#include <linux/sfp.h>
+
+/*
+ * 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.
+ */
+static bool i2c_mii_valid_phy_id(int phy_id)
+{
+	return phy_id != 0x10 && phy_id != 0x11;
+}
+
+static unsigned int i2c_mii_phy_addr(int phy_id)
+{
+	return phy_id + 0x40;
+}
+
+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);
+		*p++ = reg >> 8;
+	}
+	*p++ = reg;
+
+	bus_addr = i2c_mii_phy_addr(phy_id);
+	msgs[0].addr = bus_addr;
+	msgs[0].flags = 0;
+	msgs[0].len = p - addr;
+	msgs[0].buf = addr;
+	msgs[1].addr = bus_addr;
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].len = sizeof(data);
+	msgs[1].buf = data;
+
+	ret = i2c_transfer(i2c, msgs, ARRAY_SIZE(msgs));
+	if (ret != ARRAY_SIZE(msgs))
+		return 0xffff;
+
+	return data[0] << 8 | data[1];
+}
+
+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;
+		*p++ = reg >> 8;
+	}
+	*p++ = reg;
+	*p++ = val >> 8;
+	*p++ = val;
+
+	msg.addr = i2c_mii_phy_addr(phy_id);
+	msg.flags = 0;
+	msg.len = p - data;
+	msg.buf = data;
+
+	ret = i2c_transfer(i2c, &msg, 1);
+
+	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_PHY_I2C_ADDR		0x51
+
+#define ROLLBALL_PASSWORD		(SFP_VSL + 3)
+
+#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
+
+#define SFP_PAGE_ROLLBALL_MDIO		3
+
+static int __i2c_transfer_err(struct i2c_adapter *i2c, struct i2c_msg *msgs,
+			      int num)
+{
+	int ret;
+
+	ret = __i2c_transfer(i2c, msgs, num);
+	if (ret < 0)
+		return ret;
+	else if (ret != num)
+		return -EIO;
+	else
+		return 0;
+}
+
+static int __i2c_rollball_get_page(struct i2c_adapter *i2c, int bus_addr,
+				   u8 *page)
+{
+	struct i2c_msg msgs[2];
+	u8 addr = SFP_PAGE;
+
+	msgs[0].addr = bus_addr;
+	msgs[0].flags = 0;
+	msgs[0].len = 1;
+	msgs[0].buf = &addr;
+
+	msgs[1].addr = bus_addr;
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].len = 1;
+	msgs[1].buf = page;
+
+	return __i2c_transfer_err(i2c, msgs, 2);
+}
+
+static int __i2c_rollball_set_page(struct i2c_adapter *i2c, int bus_addr,
+				   u8 page)
+{
+	struct i2c_msg msg;
+	u8 buf[2];
+
+	buf[0] = SFP_PAGE;
+	buf[1] = page;
+
+	msg.addr = bus_addr;
+	msg.flags = 0;
+	msg.len = 2;
+	msg.buf = buf;
+
+	return __i2c_transfer_err(i2c, &msg, 1);
+}
+
+/* In order to not interfere with other SFP code (which possibly may manipulate
+ * SFP_PAGE), for every transfer we do this:
+ *   1. lock the bus
+ *   2. save content of SFP_PAGE
+ *   3. set SFP_PAGE to 3
+ *   4. do the transfer
+ *   5. restore original SFP_PAGE
+ *   6. unlock the bus
+ * Note that one might think that steps 2 to 5 could be theoretically done all
+ * in one call to i2c_transfer (by constructing msgs array in such a way), but
+ * unfortunately tests show that this does not work :-( Changed SFP_PAGE does
+ * not take into account until i2c_transfer() is done.
+ */
+static int i2c_transfer_rollball(struct i2c_adapter *i2c,
+				 struct i2c_msg *msgs, int num)
+{
+	int ret, main_err = 0;
+	u8 saved_page;
+
+	i2c_lock_bus(i2c, I2C_LOCK_SEGMENT);
+
+	/* save original page */
+	ret = __i2c_rollball_get_page(i2c, msgs->addr, &saved_page);
+	if (ret)
+		goto unlock;
+
+	/* change to RollBall MDIO page */
+	ret = __i2c_rollball_set_page(i2c, msgs->addr, SFP_PAGE_ROLLBALL_MDIO);
+	if (ret)
+		goto unlock;
+
+	/* do the transfer; we try to restore original page if this fails */
+	ret = __i2c_transfer_err(i2c, msgs, num);
+	if (ret)
+		main_err = ret;
+
+	/* restore original page */
+	ret = __i2c_rollball_set_page(i2c, msgs->addr, saved_page);
+
+unlock:
+	i2c_unlock_bus(i2c, I2C_LOCK_SEGMENT);
+
+	return main_err ? : ret;
+}
+
+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 cmd_addr, tmp, *res;
+	int i, ret;
+
+	cmd_addr = ROLLBALL_CMD_ADDR;
+
+	res = buf ? buf : &tmp;
+	len = buf ? len : 1;
+
+	msgs[0].addr = bus_addr;
+	msgs[0].flags = 0;
+	msgs[0].len = 1;
+	msgs[0].buf = &cmd_addr;
+
+	msgs[1].addr = bus_addr;
+	msgs[1].flags = I2C_M_RD;
+	msgs[1].len = len;
+	msgs[1].buf = res;
+
+	/* By experiment it takes up to 70 ms to access a register for these
+	 * SFPs. Sleep 20ms between iterations and try 10 times.
+	 */
+	i = 10;
+	do {
+		msleep(20);
+
+		ret = i2c_transfer_rollball(i2c, msgs, ARRAY_SIZE(msgs));
+		if (ret)
+			return ret;
+
+		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];
+
+	cmdbuf[0] = ROLLBALL_CMD_ADDR;
+	cmdbuf[1] = cmd;
+
+	msgs[0].addr = bus_addr;
+	msgs[0].flags = 0;
+	msgs[0].len = len;
+	msgs[0].buf = data;
+
+	msgs[1].addr = bus_addr;
+	msgs[1].flags = 0;
+	msgs[1].len = sizeof(cmdbuf);
+	msgs[1].buf = cmdbuf;
+
+	return i2c_transfer_rollball(i2c, msgs, ARRAY_SIZE(msgs));
+}
+
+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;
+
+	bus_addr = i2c_mii_phy_addr(phy_id);
+	if (bus_addr != ROLLBALL_PHY_I2C_ADDR)
+		return 0xffff;
+
+	buf[0] = ROLLBALL_DATA_ADDR;
+	buf[1] = (reg >> 16) & 0x1f;
+	buf[2] = (reg >> 8) & 0xff;
+	buf[3] = reg & 0xff;
+
+	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] << 8 | res[5];
+
+	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;
+
+	bus_addr = i2c_mii_phy_addr(phy_id);
+	if (bus_addr != ROLLBALL_PHY_I2C_ADDR)
+		return 0;
+
+	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;
+
+	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;
+
+	return 0;
+}
+
+static int i2c_mii_init_rollball(struct i2c_adapter *i2c)
+{
+	struct i2c_msg msg;
+	u8 pw[5];
+	int ret;
+
+	pw[0] = ROLLBALL_PASSWORD;
+	pw[1] = 0xff;
+	pw[2] = 0xff;
+	pw[3] = 0xff;
+	pw[4] = 0xff;
+
+	msg.addr = ROLLBALL_PHY_I2C_ADDR;
+	msg.flags = 0;
+	msg.len = sizeof(pw);
+	msg.buf = pw;
+
+	ret = i2c_transfer(i2c, &msg, 1);
+	if (ret < 0)
+		return ret;
+	else if (ret != 1)
+		return -EIO;
+	else
+		return 0;
+}
+
+struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c,
+			       enum mdio_i2c_proto protocol)
+{
+	struct mii_bus *mii;
+	int ret;
+
+	if (!i2c_check_functionality(i2c, I2C_FUNC_I2C))
+		return ERR_PTR(-EINVAL);
+
+	mii = mdiobus_alloc();
+	if (!mii)
+		return ERR_PTR(-ENOMEM);
+
+	snprintf(mii->id, MII_BUS_ID_SIZE, "i2c:%s", dev_name(parent));
+	mii->parent = parent;
+	mii->priv = i2c;
+
+	switch (protocol) {
+	case MDIO_I2C_ROLLBALL:
+		ret = i2c_mii_init_rollball(i2c);
+		if (ret < 0) {
+			dev_err(parent,
+				"Cannot initialize RollBall MDIO I2C protocol: %d\n",
+				ret);
+			mdiobus_free(mii);
+			return ERR_PTR(ret);
+		}
+
+		mii->read = i2c_mii_read_rollball;
+		mii->write = i2c_mii_write_rollball;
+		break;
+	default:
+		mii->read = i2c_mii_read_default;
+		mii->write = i2c_mii_write_default;
+		break;
+	}
+
+	return mii;
+}
+EXPORT_SYMBOL_GPL(mdio_i2c_alloc);
+
+MODULE_AUTHOR("Russell King");
+MODULE_DESCRIPTION("MDIO I2C bridge library");
+MODULE_LICENSE("GPL v2");