1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Software PHY emulation
4 *
5 * Code taken from fixed_phy.c by Russell King.
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
21struct swmii_regs {
22 u16 bmsr;
23 u16 lpa;
24 u16 lpagb;
25 u16 estat;
26};
27
28enum {
29 SWMII_SPEED_10 = 0,
30 SWMII_SPEED_100,
31 SWMII_SPEED_1000,
32 SWMII_DUPLEX_HALF = 0,
33 SWMII_DUPLEX_FULL,
34};
35
36/*
37 * These two tables get bitwise-anded together to produce the final result.
38 * This means the speed table must contain both duplex settings, and the
39 * duplex table must contain all speed settings.
40 */
41static const struct swmii_regs speed[] = {
42 [SWMII_SPEED_10] = {
43 .lpa = LPA_10FULL | LPA_10HALF,
44 },
45 [SWMII_SPEED_100] = {
46 .bmsr = BMSR_100FULL | BMSR_100HALF,
47 .lpa = LPA_100FULL | LPA_100HALF,
48 },
49 [SWMII_SPEED_1000] = {
50 .bmsr = BMSR_ESTATEN,
51 .lpagb = LPA_1000FULL | LPA_1000HALF,
52 .estat = ESTATUS_1000_TFULL | ESTATUS_1000_THALF,
53 },
54};
55
56static const struct swmii_regs duplex[] = {
57 [SWMII_DUPLEX_HALF] = {
58 .bmsr = BMSR_ESTATEN | BMSR_100HALF,
59 .lpa = LPA_10HALF | LPA_100HALF,
60 .lpagb = LPA_1000HALF,
61 .estat = ESTATUS_1000_THALF,
62 },
63 [SWMII_DUPLEX_FULL] = {
64 .bmsr = BMSR_ESTATEN | BMSR_100FULL,
65 .lpa = LPA_10FULL | LPA_100FULL,
66 .lpagb = LPA_1000FULL,
67 .estat = ESTATUS_1000_TFULL,
68 },
69};
70
71static int swphy_decode_speed(int speed)
72{
73 switch (speed) {
74 case 1000:
75 return SWMII_SPEED_1000;
76 case 100:
77 return SWMII_SPEED_100;
78 case 10:
79 return SWMII_SPEED_10;
80 default:
81 return -EINVAL;
82 }
83}
84
85/**
86 * swphy_validate_state - validate the software phy status
87 * @state: software phy status
88 *
89 * This checks that we can represent the state stored in @state can be
90 * represented in the emulated MII registers. Returns 0 if it can,
91 * otherwise returns -EINVAL.
92 */
93int swphy_validate_state(const struct fixed_phy_status *state)
94{
95 int err;
96
97 if (state->link) {
98 err = swphy_decode_speed(speed: state->speed);
99 if (err < 0) {
100 pr_warn("swphy: unknown speed\n");
101 return -EINVAL;
102 }
103 }
104 return 0;
105}
106EXPORT_SYMBOL_GPL(swphy_validate_state);
107
108/**
109 * swphy_read_reg - return a MII register from the fixed phy state
110 * @reg: MII register
111 * @state: fixed phy status
112 *
113 * Return the MII @reg register generated from the fixed phy state @state.
114 */
115int swphy_read_reg(int reg, const struct fixed_phy_status *state)
116{
117 int speed_index, duplex_index;
118 u16 bmsr = BMSR_ANEGCAPABLE;
119 u16 estat = 0;
120 u16 lpagb = 0;
121 u16 lpa = 0;
122
123 if (reg > MII_REGS_NUM)
124 return -1;
125
126 speed_index = swphy_decode_speed(speed: state->speed);
127 if (WARN_ON(speed_index < 0))
128 return 0;
129
130 duplex_index = state->duplex ? SWMII_DUPLEX_FULL : SWMII_DUPLEX_HALF;
131
132 bmsr |= speed[speed_index].bmsr & duplex[duplex_index].bmsr;
133 estat |= speed[speed_index].estat & duplex[duplex_index].estat;
134
135 if (state->link) {
136 bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE;
137
138 lpa |= speed[speed_index].lpa & duplex[duplex_index].lpa;
139 lpagb |= speed[speed_index].lpagb & duplex[duplex_index].lpagb;
140
141 if (state->pause)
142 lpa |= LPA_PAUSE_CAP;
143
144 if (state->asym_pause)
145 lpa |= LPA_PAUSE_ASYM;
146 }
147
148 switch (reg) {
149 case MII_BMCR:
150 return BMCR_ANENABLE;
151 case MII_BMSR:
152 return bmsr;
153 case MII_PHYSID1:
154 case MII_PHYSID2:
155 return 0;
156 case MII_LPA:
157 return lpa;
158 case MII_STAT1000:
159 return lpagb;
160 case MII_ESTATUS:
161 return estat;
162
163 /*
164 * We do not support emulating Clause 45 over Clause 22 register
165 * reads. Return an error instead of bogus data.
166 */
167 case MII_MMD_CTRL:
168 case MII_MMD_DATA:
169 return -1;
170
171 default:
172 return 0xffff;
173 }
174}
175EXPORT_SYMBOL_GPL(swphy_read_reg);
176