1 /*******************************************************************************
2   PTP 1588 clock using the STMMAC.
3 
4   Copyright (C) 2013  Vayavya Labs Pvt Ltd
5 
6   This program is free software; you can redistribute it and/or modify it
7   under the terms and conditions of the GNU General Public License,
8   version 2, as published by the Free Software Foundation.
9 
10   This program is distributed in the hope it will be useful, but WITHOUT
11   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13   more details.
14 
15   The full GNU General Public License is included in this distribution in
16   the file called "COPYING".
17 
18   Author: Rayagond Kokatanur <rayagond@vayavyalabs.com>
19 *******************************************************************************/
20 #include "stmmac.h"
21 #include "stmmac_ptp.h"
22 
23 /**
24  * stmmac_adjust_freq
25  *
26  * @ptp: pointer to ptp_clock_info structure
27  * @ppb: desired period change in parts ber billion
28  *
29  * Description: this function will adjust the frequency of hardware clock.
30  */
31 static int stmmac_adjust_freq(struct ptp_clock_info *ptp, s32 ppb)
32 {
33 	struct stmmac_priv *priv =
34 	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
35 	unsigned long flags;
36 	u32 diff, addend;
37 	int neg_adj = 0;
38 	u64 adj;
39 
40 	if (ppb < 0) {
41 		neg_adj = 1;
42 		ppb = -ppb;
43 	}
44 
45 	addend = priv->default_addend;
46 	adj = addend;
47 	adj *= ppb;
48 	diff = div_u64(adj, 1000000000ULL);
49 	addend = neg_adj ? (addend - diff) : (addend + diff);
50 
51 	spin_lock_irqsave(&priv->ptp_lock, flags);
52 	stmmac_config_addend(priv, priv->ptpaddr, addend);
53 	spin_unlock_irqrestore(&priv->ptp_lock, flags);
54 
55 	return 0;
56 }
57 
58 /**
59  * stmmac_adjust_time
60  *
61  * @ptp: pointer to ptp_clock_info structure
62  * @delta: desired change in nanoseconds
63  *
64  * Description: this function will shift/adjust the hardware clock time.
65  */
66 static int stmmac_adjust_time(struct ptp_clock_info *ptp, s64 delta)
67 {
68 	struct stmmac_priv *priv =
69 	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
70 	unsigned long flags;
71 	u32 sec, nsec;
72 	u32 quotient, reminder;
73 	int neg_adj = 0;
74 
75 	if (delta < 0) {
76 		neg_adj = 1;
77 		delta = -delta;
78 	}
79 
80 	quotient = div_u64_rem(delta, 1000000000ULL, &reminder);
81 	sec = quotient;
82 	nsec = reminder;
83 
84 	spin_lock_irqsave(&priv->ptp_lock, flags);
85 	stmmac_adjust_systime(priv, priv->ptpaddr, sec, nsec, neg_adj,
86 			priv->plat->has_gmac4);
87 	spin_unlock_irqrestore(&priv->ptp_lock, flags);
88 
89 	return 0;
90 }
91 
92 /**
93  * stmmac_get_time
94  *
95  * @ptp: pointer to ptp_clock_info structure
96  * @ts: pointer to hold time/result
97  *
98  * Description: this function will read the current time from the
99  * hardware clock and store it in @ts.
100  */
101 static int stmmac_get_time(struct ptp_clock_info *ptp, struct timespec64 *ts)
102 {
103 	struct stmmac_priv *priv =
104 	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
105 	unsigned long flags;
106 	u64 ns;
107 
108 	spin_lock_irqsave(&priv->ptp_lock, flags);
109 	stmmac_get_systime(priv, priv->ptpaddr, &ns);
110 	spin_unlock_irqrestore(&priv->ptp_lock, flags);
111 
112 	*ts = ns_to_timespec64(ns);
113 
114 	return 0;
115 }
116 
117 /**
118  * stmmac_set_time
119  *
120  * @ptp: pointer to ptp_clock_info structure
121  * @ts: time value to set
122  *
123  * Description: this function will set the current time on the
124  * hardware clock.
125  */
126 static int stmmac_set_time(struct ptp_clock_info *ptp,
127 			   const struct timespec64 *ts)
128 {
129 	struct stmmac_priv *priv =
130 	    container_of(ptp, struct stmmac_priv, ptp_clock_ops);
131 	unsigned long flags;
132 
133 	spin_lock_irqsave(&priv->ptp_lock, flags);
134 	stmmac_init_systime(priv, priv->ptpaddr, ts->tv_sec, ts->tv_nsec);
135 	spin_unlock_irqrestore(&priv->ptp_lock, flags);
136 
137 	return 0;
138 }
139 
140 static int stmmac_enable(struct ptp_clock_info *ptp,
141 			 struct ptp_clock_request *rq, int on)
142 {
143 	return -EOPNOTSUPP;
144 }
145 
146 /* structure describing a PTP hardware clock */
147 static const struct ptp_clock_info stmmac_ptp_clock_ops = {
148 	.owner = THIS_MODULE,
149 	.name = "stmmac_ptp_clock",
150 	.max_adj = 62500000,
151 	.n_alarm = 0,
152 	.n_ext_ts = 0,
153 	.n_per_out = 0,
154 	.n_pins = 0,
155 	.pps = 0,
156 	.adjfreq = stmmac_adjust_freq,
157 	.adjtime = stmmac_adjust_time,
158 	.gettime64 = stmmac_get_time,
159 	.settime64 = stmmac_set_time,
160 	.enable = stmmac_enable,
161 };
162 
163 /**
164  * stmmac_ptp_register
165  * @priv: driver private structure
166  * Description: this function will register the ptp clock driver
167  * to kernel. It also does some house keeping work.
168  */
169 void stmmac_ptp_register(struct stmmac_priv *priv)
170 {
171 	spin_lock_init(&priv->ptp_lock);
172 	priv->ptp_clock_ops = stmmac_ptp_clock_ops;
173 
174 	priv->ptp_clock = ptp_clock_register(&priv->ptp_clock_ops,
175 					     priv->device);
176 	if (IS_ERR(priv->ptp_clock)) {
177 		netdev_err(priv->dev, "ptp_clock_register failed\n");
178 		priv->ptp_clock = NULL;
179 	} else if (priv->ptp_clock)
180 		netdev_info(priv->dev, "registered PTP clock\n");
181 }
182 
183 /**
184  * stmmac_ptp_unregister
185  * @priv: driver private structure
186  * Description: this function will remove/unregister the ptp clock driver
187  * from the kernel.
188  */
189 void stmmac_ptp_unregister(struct stmmac_priv *priv)
190 {
191 	if (priv->ptp_clock) {
192 		ptp_clock_unregister(priv->ptp_clock);
193 		priv->ptp_clock = NULL;
194 		pr_debug("Removed PTP HW clock successfully on %s\n",
195 			 priv->dev->name);
196 	}
197 }
198