1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Software PHY emulation 4 * 5 * Code taken from fixed_phy.c by Russell King <rmk+kernel@arm.linux.org.uk> 6 * 7 * Author: Vitaly Bordug <vbordug@ru.mvista.com> 8 * Anton Vorontsov <avorontsov@ru.mvista.com> 9 * 10 * Copyright (c) 2006-2007 MontaVista Software, Inc. 11 */ 12 #include <linux/export.h> 13 #include <linux/mii.h> 14 #include <linux/phy.h> 15 #include <linux/phy_fixed.h> 16 17 #include "swphy.h" 18 19 #define MII_REGS_NUM 29 20 21 struct swmii_regs { 22 u16 bmsr; 23 u16 lpa; 24 u16 lpagb; 25 }; 26 27 enum { 28 SWMII_SPEED_10 = 0, 29 SWMII_SPEED_100, 30 SWMII_SPEED_1000, 31 SWMII_DUPLEX_HALF = 0, 32 SWMII_DUPLEX_FULL, 33 }; 34 35 /* 36 * These two tables get bitwise-anded together to produce the final result. 37 * This means the speed table must contain both duplex settings, and the 38 * duplex table must contain all speed settings. 39 */ 40 static const struct swmii_regs speed[] = { 41 [SWMII_SPEED_10] = { 42 .lpa = LPA_10FULL | LPA_10HALF, 43 }, 44 [SWMII_SPEED_100] = { 45 .bmsr = BMSR_100FULL | BMSR_100HALF, 46 .lpa = LPA_100FULL | LPA_100HALF, 47 }, 48 [SWMII_SPEED_1000] = { 49 .bmsr = BMSR_ESTATEN, 50 .lpagb = LPA_1000FULL | LPA_1000HALF, 51 }, 52 }; 53 54 static const struct swmii_regs duplex[] = { 55 [SWMII_DUPLEX_HALF] = { 56 .bmsr = BMSR_ESTATEN | BMSR_100HALF, 57 .lpa = LPA_10HALF | LPA_100HALF, 58 .lpagb = LPA_1000HALF, 59 }, 60 [SWMII_DUPLEX_FULL] = { 61 .bmsr = BMSR_ESTATEN | BMSR_100FULL, 62 .lpa = LPA_10FULL | LPA_100FULL, 63 .lpagb = LPA_1000FULL, 64 }, 65 }; 66 67 static int swphy_decode_speed(int speed) 68 { 69 switch (speed) { 70 case 1000: 71 return SWMII_SPEED_1000; 72 case 100: 73 return SWMII_SPEED_100; 74 case 10: 75 return SWMII_SPEED_10; 76 default: 77 return -EINVAL; 78 } 79 } 80 81 /** 82 * swphy_validate_state - validate the software phy status 83 * @state: software phy status 84 * 85 * This checks that we can represent the state stored in @state can be 86 * represented in the emulated MII registers. Returns 0 if it can, 87 * otherwise returns -EINVAL. 88 */ 89 int swphy_validate_state(const struct fixed_phy_status *state) 90 { 91 int err; 92 93 if (state->link) { 94 err = swphy_decode_speed(state->speed); 95 if (err < 0) { 96 pr_warn("swphy: unknown speed\n"); 97 return -EINVAL; 98 } 99 } 100 return 0; 101 } 102 EXPORT_SYMBOL_GPL(swphy_validate_state); 103 104 /** 105 * swphy_read_reg - return a MII register from the fixed phy state 106 * @reg: MII register 107 * @state: fixed phy status 108 * 109 * Return the MII @reg register generated from the fixed phy state @state. 110 */ 111 int swphy_read_reg(int reg, const struct fixed_phy_status *state) 112 { 113 int speed_index, duplex_index; 114 u16 bmsr = BMSR_ANEGCAPABLE; 115 u16 lpagb = 0; 116 u16 lpa = 0; 117 118 if (reg > MII_REGS_NUM) 119 return -1; 120 121 speed_index = swphy_decode_speed(state->speed); 122 if (WARN_ON(speed_index < 0)) 123 return 0; 124 125 duplex_index = state->duplex ? SWMII_DUPLEX_FULL : SWMII_DUPLEX_HALF; 126 127 bmsr |= speed[speed_index].bmsr & duplex[duplex_index].bmsr; 128 129 if (state->link) { 130 bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE; 131 132 lpa |= speed[speed_index].lpa & duplex[duplex_index].lpa; 133 lpagb |= speed[speed_index].lpagb & duplex[duplex_index].lpagb; 134 135 if (state->pause) 136 lpa |= LPA_PAUSE_CAP; 137 138 if (state->asym_pause) 139 lpa |= LPA_PAUSE_ASYM; 140 } 141 142 switch (reg) { 143 case MII_BMCR: 144 return BMCR_ANENABLE; 145 case MII_BMSR: 146 return bmsr; 147 case MII_PHYSID1: 148 case MII_PHYSID2: 149 return 0; 150 case MII_LPA: 151 return lpa; 152 case MII_STAT1000: 153 return lpagb; 154 155 /* 156 * We do not support emulating Clause 45 over Clause 22 register 157 * reads. Return an error instead of bogus data. 158 */ 159 case MII_MMD_CTRL: 160 case MII_MMD_DATA: 161 return -1; 162 163 default: 164 return 0xffff; 165 } 166 } 167 EXPORT_SYMBOL_GPL(swphy_read_reg); 168