1 // SPDX-License-Identifier: GPL-2.0+
3 * CPSW MDIO generic driver for TI AMxx/K2x/EMAC devices.
5 * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
13 struct cpsw_mdio_regs {
16 #define CONTROL_IDLE BIT(31)
17 #define CONTROL_ENABLE BIT(30)
18 #define CONTROL_FAULT BIT(19)
19 #define CONTROL_FAULT_ENABLE BIT(18)
20 #define CONTROL_DIV_MASK GENMASK(15, 0)
36 #define USERACCESS_GO BIT(31)
37 #define USERACCESS_WRITE BIT(30)
38 #define USERACCESS_ACK BIT(29)
39 #define USERACCESS_READ (0)
40 #define USERACCESS_PHY_REG_SHIFT (21)
41 #define USERACCESS_PHY_ADDR_SHIFT (16)
42 #define USERACCESS_DATA GENMASK(15, 0)
46 #define CPSW_MDIO_DIV_DEF 0xff
47 #define PHY_REG_MASK 0x1f
48 #define PHY_ID_MASK 0x1f
51 * This timeout definition is a worst-case ultra defensive measure against
52 * unexpected controller lock ups. Ideally, we should never ever hit this
53 * scenario in practice.
55 #define CPSW_MDIO_TIMEOUT 100 /* msecs */
58 struct cpsw_mdio_regs *regs;
63 /* wait until hardware is ready for another user access */
64 static int cpsw_mdio_wait_for_user_access(struct cpsw_mdio *mdio)
66 return wait_for_bit_le32(&mdio->regs->user[0].access,
68 CPSW_MDIO_TIMEOUT, false);
71 static int cpsw_mdio_read(struct mii_dev *bus, int phy_id,
72 int dev_addr, int phy_reg)
74 struct cpsw_mdio *mdio = bus->priv;
78 if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
81 ret = cpsw_mdio_wait_for_user_access(mdio);
84 reg = (USERACCESS_GO | USERACCESS_READ |
85 (phy_reg << USERACCESS_PHY_REG_SHIFT) |
86 (phy_id << USERACCESS_PHY_ADDR_SHIFT));
87 writel(reg, &mdio->regs->user[0].access);
88 ret = cpsw_mdio_wait_for_user_access(mdio);
92 reg = readl(&mdio->regs->user[0].access);
93 data = (reg & USERACCESS_ACK) ? (reg & USERACCESS_DATA) : -1;
97 static int cpsw_mdio_write(struct mii_dev *bus, int phy_id, int dev_addr,
98 int phy_reg, u16 data)
100 struct cpsw_mdio *mdio = bus->priv;
104 if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
107 ret = cpsw_mdio_wait_for_user_access(mdio);
110 reg = (USERACCESS_GO | USERACCESS_WRITE |
111 (phy_reg << USERACCESS_PHY_REG_SHIFT) |
112 (phy_id << USERACCESS_PHY_ADDR_SHIFT) |
113 (data & USERACCESS_DATA));
114 writel(reg, &mdio->regs->user[0].access);
116 return cpsw_mdio_wait_for_user_access(mdio);
119 u32 cpsw_mdio_get_alive(struct mii_dev *bus)
121 struct cpsw_mdio *mdio = bus->priv;
124 val = readl(&mdio->regs->control);
125 return val & GENMASK(15, 0);
128 struct mii_dev *cpsw_mdio_init(const char *name, u32 mdio_base,
129 u32 bus_freq, int fck_freq)
131 struct cpsw_mdio *cpsw_mdio;
134 cpsw_mdio = calloc(1, sizeof(*cpsw_mdio));
136 debug("failed to alloc cpsw_mdio\n");
140 cpsw_mdio->bus = mdio_alloc();
141 if (!cpsw_mdio->bus) {
142 debug("failed to alloc mii bus\n");
147 cpsw_mdio->regs = (struct cpsw_mdio_regs *)mdio_base;
149 if (!bus_freq || !fck_freq)
150 cpsw_mdio->div = CPSW_MDIO_DIV_DEF;
152 cpsw_mdio->div = (fck_freq / bus_freq) - 1;
153 cpsw_mdio->div &= CONTROL_DIV_MASK;
155 /* set enable and clock divider */
156 writel(cpsw_mdio->div | CONTROL_ENABLE | CONTROL_FAULT |
157 CONTROL_FAULT_ENABLE, &cpsw_mdio->regs->control);
158 wait_for_bit_le32(&cpsw_mdio->regs->control,
159 CONTROL_IDLE, false, CPSW_MDIO_TIMEOUT, true);
162 * wait for scan logic to settle:
163 * the scan time consists of (a) a large fixed component, and (b) a
164 * small component that varies with the mii bus frequency. These
165 * were estimated using measurements at 1.1 and 2.2 MHz on tnetv107x
166 * silicon. Since the effect of (b) was found to be largely
167 * negligible, we keep things simple here.
171 cpsw_mdio->bus->read = cpsw_mdio_read;
172 cpsw_mdio->bus->write = cpsw_mdio_write;
173 cpsw_mdio->bus->priv = cpsw_mdio;
174 snprintf(cpsw_mdio->bus->name, sizeof(cpsw_mdio->bus->name), name);
176 ret = mdio_register(cpsw_mdio->bus);
178 debug("failed to register mii bus\n");
182 return cpsw_mdio->bus;
185 mdio_free(cpsw_mdio->bus);
190 void cpsw_mdio_free(struct mii_dev *bus)
192 struct cpsw_mdio *mdio = bus->priv;
196 reg = readl(&mdio->regs->control);
197 reg &= ~CONTROL_ENABLE;
198 writel(reg, &mdio->regs->control);
200 mdio_unregister(bus);