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/
14 #include <linux/bitops.h>
15 #include <linux/delay.h>
17 struct cpsw_mdio_regs {
20 #define CONTROL_IDLE BIT(31)
21 #define CONTROL_ENABLE BIT(30)
22 #define CONTROL_FAULT BIT(19)
23 #define CONTROL_FAULT_ENABLE BIT(18)
24 #define CONTROL_DIV_MASK GENMASK(15, 0)
40 #define USERACCESS_GO BIT(31)
41 #define USERACCESS_WRITE BIT(30)
42 #define USERACCESS_ACK BIT(29)
43 #define USERACCESS_READ (0)
44 #define USERACCESS_PHY_REG_SHIFT (21)
45 #define USERACCESS_PHY_ADDR_SHIFT (16)
46 #define USERACCESS_DATA GENMASK(15, 0)
50 #define CPSW_MDIO_DIV_DEF 0xff
51 #define PHY_REG_MASK 0x1f
52 #define PHY_ID_MASK 0x1f
55 * This timeout definition is a worst-case ultra defensive measure against
56 * unexpected controller lock ups. Ideally, we should never ever hit this
57 * scenario in practice.
59 #define CPSW_MDIO_TIMEOUT 100 /* msecs */
62 struct cpsw_mdio_regs *regs;
67 /* wait until hardware is ready for another user access */
68 static int cpsw_mdio_wait_for_user_access(struct cpsw_mdio *mdio)
70 return wait_for_bit_le32(&mdio->regs->user[0].access,
72 CPSW_MDIO_TIMEOUT, false);
75 static int cpsw_mdio_read(struct mii_dev *bus, int phy_id,
76 int dev_addr, int phy_reg)
78 struct cpsw_mdio *mdio = bus->priv;
82 if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
85 ret = cpsw_mdio_wait_for_user_access(mdio);
88 reg = (USERACCESS_GO | USERACCESS_READ |
89 (phy_reg << USERACCESS_PHY_REG_SHIFT) |
90 (phy_id << USERACCESS_PHY_ADDR_SHIFT));
91 writel(reg, &mdio->regs->user[0].access);
92 ret = cpsw_mdio_wait_for_user_access(mdio);
96 reg = readl(&mdio->regs->user[0].access);
97 data = (reg & USERACCESS_ACK) ? (reg & USERACCESS_DATA) : -1;
101 static int cpsw_mdio_write(struct mii_dev *bus, int phy_id, int dev_addr,
102 int phy_reg, u16 data)
104 struct cpsw_mdio *mdio = bus->priv;
108 if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
111 ret = cpsw_mdio_wait_for_user_access(mdio);
114 reg = (USERACCESS_GO | USERACCESS_WRITE |
115 (phy_reg << USERACCESS_PHY_REG_SHIFT) |
116 (phy_id << USERACCESS_PHY_ADDR_SHIFT) |
117 (data & USERACCESS_DATA));
118 writel(reg, &mdio->regs->user[0].access);
120 return cpsw_mdio_wait_for_user_access(mdio);
123 u32 cpsw_mdio_get_alive(struct mii_dev *bus)
125 struct cpsw_mdio *mdio = bus->priv;
128 val = readl(&mdio->regs->control);
129 return val & GENMASK(15, 0);
132 struct mii_dev *cpsw_mdio_init(const char *name, phys_addr_t mdio_base,
133 u32 bus_freq, int fck_freq)
135 struct cpsw_mdio *cpsw_mdio;
138 cpsw_mdio = calloc(1, sizeof(*cpsw_mdio));
140 debug("failed to alloc cpsw_mdio\n");
144 cpsw_mdio->bus = mdio_alloc();
145 if (!cpsw_mdio->bus) {
146 debug("failed to alloc mii bus\n");
151 cpsw_mdio->regs = (struct cpsw_mdio_regs *)(uintptr_t)mdio_base;
153 if (!bus_freq || !fck_freq)
154 cpsw_mdio->div = CPSW_MDIO_DIV_DEF;
156 cpsw_mdio->div = (fck_freq / bus_freq) - 1;
157 cpsw_mdio->div &= CONTROL_DIV_MASK;
159 /* set enable and clock divider */
160 writel(cpsw_mdio->div | CONTROL_ENABLE | CONTROL_FAULT |
161 CONTROL_FAULT_ENABLE, &cpsw_mdio->regs->control);
162 wait_for_bit_le32(&cpsw_mdio->regs->control,
163 CONTROL_IDLE, false, CPSW_MDIO_TIMEOUT, true);
166 * wait for scan logic to settle:
167 * the scan time consists of (a) a large fixed component, and (b) a
168 * small component that varies with the mii bus frequency. These
169 * were estimated using measurements at 1.1 and 2.2 MHz on tnetv107x
170 * silicon. Since the effect of (b) was found to be largely
171 * negligible, we keep things simple here.
175 cpsw_mdio->bus->read = cpsw_mdio_read;
176 cpsw_mdio->bus->write = cpsw_mdio_write;
177 cpsw_mdio->bus->priv = cpsw_mdio;
178 snprintf(cpsw_mdio->bus->name, sizeof(cpsw_mdio->bus->name), name);
180 ret = mdio_register(cpsw_mdio->bus);
182 debug("failed to register mii bus\n");
186 return cpsw_mdio->bus;
189 mdio_free(cpsw_mdio->bus);
194 void cpsw_mdio_free(struct mii_dev *bus)
196 struct cpsw_mdio *mdio = bus->priv;
200 reg = readl(&mdio->regs->control);
201 reg &= ~CONTROL_ENABLE;
202 writel(reg, &mdio->regs->control);
204 mdio_unregister(bus);