GNU Linux-libre 4.19.314-gnu1
[releases.git] / drivers / net / phy / swphy.c
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
25 struct swmii_regs {
26         u16 bmcr;
27         u16 bmsr;
28         u16 lpa;
29         u16 lpagb;
30 };
31
32 enum {
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  */
45 static 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
62 static 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
77 static 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  */
99 int 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 }
112 EXPORT_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  */
121 int 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 }
179 EXPORT_SYMBOL_GPL(swphy_read_reg);