1/*
  2 * Software PHY emulation
  3 *
  4 * Code taken from fixed_phy.c by Russell King <rmk+kernel@arm.linux.org.uk>
  5 *
  6 * Author: Vitaly Bordug <vbordug@ru.mvista.com>
  7 *         Anton Vorontsov <avorontsov@ru.mvista.com>
  8 *
  9 * Copyright (c) 2006-2007 MontaVista Software, Inc.
 10 *
 11 * This program is free software; you can redistribute  it and/or modify it
 12 * under  the terms of  the GNU General  Public License as published by the
 13 * Free Software Foundation;  either version 2 of the  License, or (at your
 14 * option) any later version.
 15 */
 16#include <linux/export.h>
 17#include <linux/mii.h>
 18#include <linux/phy.h>
 19#include <linux/phy_fixed.h>
 20
 21#include "swphy.h"
 22
 23#define MII_REGS_NUM 29
 24
 25struct swmii_regs {
 26	u16 bmcr;
 27	u16 bmsr;
 28	u16 lpa;
 29	u16 lpagb;
 30};
 31
 32enum {
 33	SWMII_SPEED_10 = 0,
 34	SWMII_SPEED_100,
 35	SWMII_SPEED_1000,
 36	SWMII_DUPLEX_HALF = 0,
 37	SWMII_DUPLEX_FULL,
 38};
 39
 40/*
 41 * These two tables get bitwise-anded together to produce the final result.
 42 * This means the speed table must contain both duplex settings, and the
 43 * duplex table must contain all speed settings.
 44 */
 45static const struct swmii_regs speed[] = {
 46	[SWMII_SPEED_10] = {
 47		.bmcr  = BMCR_FULLDPLX,
 48		.lpa   = LPA_10FULL | LPA_10HALF,
 49	},
 50	[SWMII_SPEED_100] = {
 51		.bmcr  = BMCR_FULLDPLX | BMCR_SPEED100,
 52		.bmsr  = BMSR_100FULL | BMSR_100HALF,
 53		.lpa   = LPA_100FULL | LPA_100HALF,
 54	},
 55	[SWMII_SPEED_1000] = {
 56		.bmcr  = BMCR_FULLDPLX | BMCR_SPEED1000,
 57		.bmsr  = BMSR_ESTATEN,
 58		.lpagb = LPA_1000FULL | LPA_1000HALF,
 59	},
 60};
 61
 62static const struct swmii_regs duplex[] = {
 63	[SWMII_DUPLEX_HALF] = {
 64		.bmcr  = ~BMCR_FULLDPLX,
 65		.bmsr  = BMSR_ESTATEN | BMSR_100HALF,
 66		.lpa   = LPA_10HALF | LPA_100HALF,
 67		.lpagb = LPA_1000HALF,
 68	},
 69	[SWMII_DUPLEX_FULL] = {
 70		.bmcr  = ~0,
 71		.bmsr  = BMSR_ESTATEN | BMSR_100FULL,
 72		.lpa   = LPA_10FULL | LPA_100FULL,
 73		.lpagb = LPA_1000FULL,
 74	},
 75};
 76
 77static int swphy_decode_speed(int speed)
 78{
 79	switch (speed) {
 80	case 1000:
 81		return SWMII_SPEED_1000;
 82	case 100:
 83		return SWMII_SPEED_100;
 84	case 10:
 85		return SWMII_SPEED_10;
 86	default:
 87		return -EINVAL;
 88	}
 89}
 90
 91/**
 92 * swphy_validate_state - validate the software phy status
 93 * @state: software phy status
 94 *
 95 * This checks that we can represent the state stored in @state can be
 96 * represented in the emulated MII registers.  Returns 0 if it can,
 97 * otherwise returns -EINVAL.
 98 */
 99int swphy_validate_state(const struct fixed_phy_status *state)
100{
101	int err;
102
103	if (state->link) {
104		err = swphy_decode_speed(state->speed);
105		if (err < 0) {
106			pr_warn("swphy: unknown speed\n");
107			return -EINVAL;
108		}
109	}
110	return 0;
111}
112EXPORT_SYMBOL_GPL(swphy_validate_state);
113
114/**
115 * swphy_read_reg - return a MII register from the fixed phy state
116 * @reg: MII register
117 * @state: fixed phy status
118 *
119 * Return the MII @reg register generated from the fixed phy state @state.
120 */
121int swphy_read_reg(int reg, const struct fixed_phy_status *state)
122{
123	int speed_index, duplex_index;
124	u16 bmsr = BMSR_ANEGCAPABLE;
125	u16 bmcr = 0;
126	u16 lpagb = 0;
127	u16 lpa = 0;
128
129	if (reg > MII_REGS_NUM)
130		return -1;
131
132	speed_index = swphy_decode_speed(state->speed);
133	if (WARN_ON(speed_index < 0))
134		return 0;
135
136	duplex_index = state->duplex ? SWMII_DUPLEX_FULL : SWMII_DUPLEX_HALF;
137
138	bmsr |= speed[speed_index].bmsr & duplex[duplex_index].bmsr;
139
140	if (state->link) {
141		bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE;
142
143		bmcr  |= speed[speed_index].bmcr  & duplex[duplex_index].bmcr;
144		lpa   |= speed[speed_index].lpa   & duplex[duplex_index].lpa;
145		lpagb |= speed[speed_index].lpagb & duplex[duplex_index].lpagb;
146
147		if (state->pause)
148			lpa |= LPA_PAUSE_CAP;
149
150		if (state->asym_pause)
151			lpa |= LPA_PAUSE_ASYM;
152	}
153
154	switch (reg) {
155	case MII_BMCR:
156		return bmcr;
157	case MII_BMSR:
158		return bmsr;
159	case MII_PHYSID1:
160	case MII_PHYSID2:
161		return 0;
162	case MII_LPA:
163		return lpa;
164	case MII_STAT1000:
165		return lpagb;
166
167	/*
168	 * We do not support emulating Clause 45 over Clause 22 register
169	 * reads.  Return an error instead of bogus data.
170	 */
171	case MII_MMD_CTRL:
172	case MII_MMD_DATA:
173		return -1;
174
175	default:
176		return 0xffff;
177	}
178}
179EXPORT_SYMBOL_GPL(swphy_read_reg);