smi.c (5001B)
1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Marvell 88E6xxx System Management Interface (SMI) support 4 * 5 * Copyright (c) 2008 Marvell Semiconductor 6 * 7 * Copyright (c) 2019 Vivien Didelot <vivien.didelot@gmail.com> 8 */ 9 10#include "chip.h" 11#include "smi.h" 12 13/* The switch ADDR[4:1] configuration pins define the chip SMI device address 14 * (ADDR[0] is always zero, thus only even SMI addresses can be strapped). 15 * 16 * When ADDR is all zero, the chip uses Single-chip Addressing Mode, assuming it 17 * is the only device connected to the SMI master. In this mode it responds to 18 * all 32 possible SMI addresses, and thus maps directly the internal devices. 19 * 20 * When ADDR is non-zero, the chip uses Multi-chip Addressing Mode, allowing 21 * multiple devices to share the SMI interface. In this mode it responds to only 22 * 2 registers, used to indirectly access the internal SMI devices. 23 * 24 * Some chips use a different scheme: Only the ADDR4 pin is used for 25 * configuration, and the device responds to 16 of the 32 SMI 26 * addresses, allowing two to coexist on the same SMI interface. 27 */ 28 29static int mv88e6xxx_smi_direct_read(struct mv88e6xxx_chip *chip, 30 int dev, int reg, u16 *data) 31{ 32 int ret; 33 34 ret = mdiobus_read_nested(chip->bus, dev, reg); 35 if (ret < 0) 36 return ret; 37 38 *data = ret & 0xffff; 39 40 return 0; 41} 42 43static int mv88e6xxx_smi_direct_write(struct mv88e6xxx_chip *chip, 44 int dev, int reg, u16 data) 45{ 46 int ret; 47 48 ret = mdiobus_write_nested(chip->bus, dev, reg, data); 49 if (ret < 0) 50 return ret; 51 52 return 0; 53} 54 55static int mv88e6xxx_smi_direct_wait(struct mv88e6xxx_chip *chip, 56 int dev, int reg, int bit, int val) 57{ 58 const unsigned long timeout = jiffies + msecs_to_jiffies(50); 59 u16 data; 60 int err; 61 int i; 62 63 /* Even if the initial poll takes longer than 50ms, always do 64 * at least one more attempt. 65 */ 66 for (i = 0; time_before(jiffies, timeout) || (i < 2); i++) { 67 err = mv88e6xxx_smi_direct_read(chip, dev, reg, &data); 68 if (err) 69 return err; 70 71 if (!!(data & BIT(bit)) == !!val) 72 return 0; 73 74 if (i < 2) 75 cpu_relax(); 76 else 77 usleep_range(1000, 2000); 78 } 79 80 return -ETIMEDOUT; 81} 82 83static const struct mv88e6xxx_bus_ops mv88e6xxx_smi_direct_ops = { 84 .read = mv88e6xxx_smi_direct_read, 85 .write = mv88e6xxx_smi_direct_write, 86}; 87 88static int mv88e6xxx_smi_dual_direct_read(struct mv88e6xxx_chip *chip, 89 int dev, int reg, u16 *data) 90{ 91 return mv88e6xxx_smi_direct_read(chip, chip->sw_addr + dev, reg, data); 92} 93 94static int mv88e6xxx_smi_dual_direct_write(struct mv88e6xxx_chip *chip, 95 int dev, int reg, u16 data) 96{ 97 return mv88e6xxx_smi_direct_write(chip, chip->sw_addr + dev, reg, data); 98} 99 100static const struct mv88e6xxx_bus_ops mv88e6xxx_smi_dual_direct_ops = { 101 .read = mv88e6xxx_smi_dual_direct_read, 102 .write = mv88e6xxx_smi_dual_direct_write, 103}; 104 105/* Offset 0x00: SMI Command Register 106 * Offset 0x01: SMI Data Register 107 */ 108 109static int mv88e6xxx_smi_indirect_read(struct mv88e6xxx_chip *chip, 110 int dev, int reg, u16 *data) 111{ 112 int err; 113 114 err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr, 115 MV88E6XXX_SMI_CMD, 116 MV88E6XXX_SMI_CMD_BUSY | 117 MV88E6XXX_SMI_CMD_MODE_22 | 118 MV88E6XXX_SMI_CMD_OP_22_READ | 119 (dev << 5) | reg); 120 if (err) 121 return err; 122 123 err = mv88e6xxx_smi_direct_wait(chip, chip->sw_addr, 124 MV88E6XXX_SMI_CMD, 15, 0); 125 if (err) 126 return err; 127 128 return mv88e6xxx_smi_direct_read(chip, chip->sw_addr, 129 MV88E6XXX_SMI_DATA, data); 130} 131 132static int mv88e6xxx_smi_indirect_write(struct mv88e6xxx_chip *chip, 133 int dev, int reg, u16 data) 134{ 135 int err; 136 137 err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr, 138 MV88E6XXX_SMI_DATA, data); 139 if (err) 140 return err; 141 142 err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr, 143 MV88E6XXX_SMI_CMD, 144 MV88E6XXX_SMI_CMD_BUSY | 145 MV88E6XXX_SMI_CMD_MODE_22 | 146 MV88E6XXX_SMI_CMD_OP_22_WRITE | 147 (dev << 5) | reg); 148 if (err) 149 return err; 150 151 return mv88e6xxx_smi_direct_wait(chip, chip->sw_addr, 152 MV88E6XXX_SMI_CMD, 15, 0); 153} 154 155static int mv88e6xxx_smi_indirect_init(struct mv88e6xxx_chip *chip) 156{ 157 /* Ensure that the chip starts out in the ready state. As both 158 * reads and writes always ensure this on return, they can 159 * safely depend on the chip not being busy on entry. 160 */ 161 return mv88e6xxx_smi_direct_wait(chip, chip->sw_addr, 162 MV88E6XXX_SMI_CMD, 15, 0); 163} 164 165static const struct mv88e6xxx_bus_ops mv88e6xxx_smi_indirect_ops = { 166 .read = mv88e6xxx_smi_indirect_read, 167 .write = mv88e6xxx_smi_indirect_write, 168 .init = mv88e6xxx_smi_indirect_init, 169}; 170 171int mv88e6xxx_smi_init(struct mv88e6xxx_chip *chip, 172 struct mii_bus *bus, int sw_addr) 173{ 174 if (chip->info->dual_chip) 175 chip->smi_ops = &mv88e6xxx_smi_dual_direct_ops; 176 else if (sw_addr == 0) 177 chip->smi_ops = &mv88e6xxx_smi_direct_ops; 178 else if (chip->info->multi_chip) 179 chip->smi_ops = &mv88e6xxx_smi_indirect_ops; 180 else 181 return -EINVAL; 182 183 chip->bus = bus; 184 chip->sw_addr = sw_addr; 185 186 if (chip->smi_ops->init) 187 return chip->smi_ops->init(chip); 188 189 return 0; 190}