1 // SPDX-License-Identifier: GPL-2.0-only
2 /*******************************************************************************
3   Copyright (C) 2013  Vayavya Labs Pvt Ltd
4 
5   This implements all the API for managing HW timestamp & PTP.
6 
7 
8   Author: Rayagond Kokatanur <rayagond@vayavyalabs.com>
9   Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
10 *******************************************************************************/
11 
12 #include <linux/io.h>
13 #include <linux/iopoll.h>
14 #include <linux/delay.h>
15 #include <linux/ptp_clock_kernel.h>
16 #include "common.h"
17 #include "stmmac_ptp.h"
18 #include "dwmac4.h"
19 #include "stmmac.h"
20 
21 static void config_hw_tstamping(void __iomem *ioaddr, u32 data)
22 {
23 	writel(data, ioaddr + PTP_TCR);
24 }
25 
26 static void config_sub_second_increment(void __iomem *ioaddr,
27 		u32 ptp_clock, int gmac4, u32 *ssinc)
28 {
29 	u32 value = readl(ioaddr + PTP_TCR);
30 	unsigned long data;
31 	u32 reg_value;
32 
33 	/* For GMAC3.x, 4.x versions, in "fine adjustement mode" set sub-second
34 	 * increment to twice the number of nanoseconds of a clock cycle.
35 	 * The calculation of the default_addend value by the caller will set it
36 	 * to mid-range = 2^31 when the remainder of this division is zero,
37 	 * which will make the accumulator overflow once every 2 ptp_clock
38 	 * cycles, adding twice the number of nanoseconds of a clock cycle :
39 	 * 2000000000ULL / ptp_clock.
40 	 */
41 	if (value & PTP_TCR_TSCFUPDT)
42 		data = (2000000000ULL / ptp_clock);
43 	else
44 		data = (1000000000ULL / ptp_clock);
45 
46 	/* 0.465ns accuracy */
47 	if (!(value & PTP_TCR_TSCTRLSSR))
48 		data = (data * 1000) / 465;
49 
50 	data &= PTP_SSIR_SSINC_MASK;
51 
52 	reg_value = data;
53 	if (gmac4)
54 		reg_value <<= GMAC4_PTP_SSIR_SSINC_SHIFT;
55 
56 	writel(reg_value, ioaddr + PTP_SSIR);
57 
58 	if (ssinc)
59 		*ssinc = data;
60 }
61 
62 static int init_systime(void __iomem *ioaddr, u32 sec, u32 nsec)
63 {
64 	u32 value;
65 
66 	writel(sec, ioaddr + PTP_STSUR);
67 	writel(nsec, ioaddr + PTP_STNSUR);
68 	/* issue command to initialize the system time value */
69 	value = readl(ioaddr + PTP_TCR);
70 	value |= PTP_TCR_TSINIT;
71 	writel(value, ioaddr + PTP_TCR);
72 
73 	/* wait for present system time initialize to complete */
74 	return readl_poll_timeout_atomic(ioaddr + PTP_TCR, value,
75 				 !(value & PTP_TCR_TSINIT),
76 				 10, 100000);
77 }
78 
79 static int config_addend(void __iomem *ioaddr, u32 addend)
80 {
81 	u32 value;
82 	int limit;
83 
84 	writel(addend, ioaddr + PTP_TAR);
85 	/* issue command to update the addend value */
86 	value = readl(ioaddr + PTP_TCR);
87 	value |= PTP_TCR_TSADDREG;
88 	writel(value, ioaddr + PTP_TCR);
89 
90 	/* wait for present addend update to complete */
91 	limit = 10;
92 	while (limit--) {
93 		if (!(readl(ioaddr + PTP_TCR) & PTP_TCR_TSADDREG))
94 			break;
95 		mdelay(10);
96 	}
97 	if (limit < 0)
98 		return -EBUSY;
99 
100 	return 0;
101 }
102 
103 static int adjust_systime(void __iomem *ioaddr, u32 sec, u32 nsec,
104 		int add_sub, int gmac4)
105 {
106 	u32 value;
107 	int limit;
108 
109 	if (add_sub) {
110 		/* If the new sec value needs to be subtracted with
111 		 * the system time, then MAC_STSUR reg should be
112 		 * programmed with (2^32 – <new_sec_value>)
113 		 */
114 		if (gmac4)
115 			sec = -sec;
116 
117 		value = readl(ioaddr + PTP_TCR);
118 		if (value & PTP_TCR_TSCTRLSSR)
119 			nsec = (PTP_DIGITAL_ROLLOVER_MODE - nsec);
120 		else
121 			nsec = (PTP_BINARY_ROLLOVER_MODE - nsec);
122 	}
123 
124 	writel(sec, ioaddr + PTP_STSUR);
125 	value = (add_sub << PTP_STNSUR_ADDSUB_SHIFT) | nsec;
126 	writel(value, ioaddr + PTP_STNSUR);
127 
128 	/* issue command to initialize the system time value */
129 	value = readl(ioaddr + PTP_TCR);
130 	value |= PTP_TCR_TSUPDT;
131 	writel(value, ioaddr + PTP_TCR);
132 
133 	/* wait for present system time adjust/update to complete */
134 	limit = 10;
135 	while (limit--) {
136 		if (!(readl(ioaddr + PTP_TCR) & PTP_TCR_TSUPDT))
137 			break;
138 		mdelay(10);
139 	}
140 	if (limit < 0)
141 		return -EBUSY;
142 
143 	return 0;
144 }
145 
146 static void get_systime(void __iomem *ioaddr, u64 *systime)
147 {
148 	u64 ns, sec0, sec1;
149 
150 	/* Get the TSS value */
151 	sec1 = readl_relaxed(ioaddr + PTP_STSR);
152 	do {
153 		sec0 = sec1;
154 		/* Get the TSSS value */
155 		ns = readl_relaxed(ioaddr + PTP_STNSR);
156 		/* Get the TSS value */
157 		sec1 = readl_relaxed(ioaddr + PTP_STSR);
158 	} while (sec0 != sec1);
159 
160 	if (systime)
161 		*systime = ns + (sec1 * 1000000000ULL);
162 }
163 
164 static void get_ptptime(void __iomem *ptpaddr, u64 *ptp_time)
165 {
166 	u64 ns;
167 
168 	ns = readl(ptpaddr + PTP_ATNR);
169 	ns += readl(ptpaddr + PTP_ATSR) * NSEC_PER_SEC;
170 
171 	*ptp_time = ns;
172 }
173 
174 static void timestamp_interrupt(struct stmmac_priv *priv)
175 {
176 	u32 num_snapshot, ts_status, tsync_int;
177 	struct ptp_clock_event event;
178 	unsigned long flags;
179 	u64 ptp_time;
180 	int i;
181 
182 	if (priv->plat->int_snapshot_en) {
183 		wake_up(&priv->tstamp_busy_wait);
184 		return;
185 	}
186 
187 	tsync_int = readl(priv->ioaddr + GMAC_INT_STATUS) & GMAC_INT_TSIE;
188 
189 	if (!tsync_int)
190 		return;
191 
192 	/* Read timestamp status to clear interrupt from either external
193 	 * timestamp or start/end of PPS.
194 	 */
195 	ts_status = readl(priv->ioaddr + GMAC_TIMESTAMP_STATUS);
196 
197 	if (!priv->plat->ext_snapshot_en)
198 		return;
199 
200 	num_snapshot = (ts_status & GMAC_TIMESTAMP_ATSNS_MASK) >>
201 		       GMAC_TIMESTAMP_ATSNS_SHIFT;
202 
203 	for (i = 0; i < num_snapshot; i++) {
204 		read_lock_irqsave(&priv->ptp_lock, flags);
205 		get_ptptime(priv->ptpaddr, &ptp_time);
206 		read_unlock_irqrestore(&priv->ptp_lock, flags);
207 		event.type = PTP_CLOCK_EXTTS;
208 		event.index = 0;
209 		event.timestamp = ptp_time;
210 		ptp_clock_event(priv->ptp_clock, &event);
211 	}
212 }
213 
214 const struct stmmac_hwtimestamp stmmac_ptp = {
215 	.config_hw_tstamping = config_hw_tstamping,
216 	.init_systime = init_systime,
217 	.config_sub_second_increment = config_sub_second_increment,
218 	.config_addend = config_addend,
219 	.adjust_systime = adjust_systime,
220 	.get_systime = get_systime,
221 	.get_ptptime = get_ptptime,
222 	.timestamp_interrupt = timestamp_interrupt,
223 };
224