13197Scsgr// SPDX-License-Identifier: GPL-2.0+
26067Swpaul/*
31590Srgrimes * Software PHY emulation
41590Srgrimes *
56067Swpaul * Code taken from fixed_phy.c by Russell King.
62158Scsgr *
71590Srgrimes * Author: Vitaly Bordug <vbordug@ru.mvista.com>
86067Swpaul *         Anton Vorontsov <avorontsov@ru.mvista.com>
93197Scsgr *
106067Swpaul * Copyright (c) 2006-2007 MontaVista Software, Inc.
116067Swpaul */
126067Swpaul#include <linux/export.h>
136067Swpaul#include <linux/mii.h>
146067Swpaul#include <linux/phy.h>
156067Swpaul#include <linux/phy_fixed.h>
166067Swpaul
176067Swpaul#include "swphy.h"
186067Swpaul
191590Srgrimes#define MII_REGS_NUM 29
201590Srgrimes
211590Srgrimesstruct swmii_regs {
221590Srgrimes	u16 bmsr;
231590Srgrimes	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(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(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