1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PTP 1588 clock using the IXP46X
4  *
5  * Copyright (C) 2010 OMICRON electronics GmbH
6  */
7 #include <linux/device.h>
8 #include <linux/module.h>
9 #include <linux/mod_devicetable.h>
10 #include <linux/err.h>
11 #include <linux/init.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/irq.h>
15 #include <linux/kernel.h>
16 #include <linux/ptp_clock_kernel.h>
17 #include <linux/platform_device.h>
18 #include <linux/soc/ixp4xx/cpu.h>
19 
20 #include "ixp46x_ts.h"
21 
22 #define DRIVER		"ptp_ixp46x"
23 #define N_EXT_TS	2
24 
25 struct ixp_clock {
26 	struct ixp46x_ts_regs *regs;
27 	struct ptp_clock *ptp_clock;
28 	struct ptp_clock_info caps;
29 	int exts0_enabled;
30 	int exts1_enabled;
31 	int slave_irq;
32 	int master_irq;
33 };
34 
35 static DEFINE_SPINLOCK(register_lock);
36 
37 /*
38  * Register access functions
39  */
40 
41 static u64 ixp_systime_read(struct ixp46x_ts_regs *regs)
42 {
43 	u64 ns;
44 	u32 lo, hi;
45 
46 	lo = __raw_readl(&regs->systime_lo);
47 	hi = __raw_readl(&regs->systime_hi);
48 
49 	ns = ((u64) hi) << 32;
50 	ns |= lo;
51 	ns <<= TICKS_NS_SHIFT;
52 
53 	return ns;
54 }
55 
56 static void ixp_systime_write(struct ixp46x_ts_regs *regs, u64 ns)
57 {
58 	u32 hi, lo;
59 
60 	ns >>= TICKS_NS_SHIFT;
61 	hi = ns >> 32;
62 	lo = ns & 0xffffffff;
63 
64 	__raw_writel(lo, &regs->systime_lo);
65 	__raw_writel(hi, &regs->systime_hi);
66 }
67 
68 /*
69  * Interrupt service routine
70  */
71 
72 static irqreturn_t isr(int irq, void *priv)
73 {
74 	struct ixp_clock *ixp_clock = priv;
75 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
76 	struct ptp_clock_event event;
77 	u32 ack = 0, lo, hi, val;
78 
79 	val = __raw_readl(&regs->event);
80 
81 	if (val & TSER_SNS) {
82 		ack |= TSER_SNS;
83 		if (ixp_clock->exts0_enabled) {
84 			hi = __raw_readl(&regs->asms_hi);
85 			lo = __raw_readl(&regs->asms_lo);
86 			event.type = PTP_CLOCK_EXTTS;
87 			event.index = 0;
88 			event.timestamp = ((u64) hi) << 32;
89 			event.timestamp |= lo;
90 			event.timestamp <<= TICKS_NS_SHIFT;
91 			ptp_clock_event(ixp_clock->ptp_clock, &event);
92 		}
93 	}
94 
95 	if (val & TSER_SNM) {
96 		ack |= TSER_SNM;
97 		if (ixp_clock->exts1_enabled) {
98 			hi = __raw_readl(&regs->amms_hi);
99 			lo = __raw_readl(&regs->amms_lo);
100 			event.type = PTP_CLOCK_EXTTS;
101 			event.index = 1;
102 			event.timestamp = ((u64) hi) << 32;
103 			event.timestamp |= lo;
104 			event.timestamp <<= TICKS_NS_SHIFT;
105 			ptp_clock_event(ixp_clock->ptp_clock, &event);
106 		}
107 	}
108 
109 	if (val & TTIPEND)
110 		ack |= TTIPEND; /* this bit seems to be always set */
111 
112 	if (ack) {
113 		__raw_writel(ack, &regs->event);
114 		return IRQ_HANDLED;
115 	} else
116 		return IRQ_NONE;
117 }
118 
119 /*
120  * PTP clock operations
121  */
122 
123 static int ptp_ixp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
124 {
125 	u64 adj;
126 	u32 diff, addend;
127 	int neg_adj = 0;
128 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
129 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
130 
131 	if (ppb < 0) {
132 		neg_adj = 1;
133 		ppb = -ppb;
134 	}
135 	addend = DEFAULT_ADDEND;
136 	adj = addend;
137 	adj *= ppb;
138 	diff = div_u64(adj, 1000000000ULL);
139 
140 	addend = neg_adj ? addend - diff : addend + diff;
141 
142 	__raw_writel(addend, &regs->addend);
143 
144 	return 0;
145 }
146 
147 static int ptp_ixp_adjtime(struct ptp_clock_info *ptp, s64 delta)
148 {
149 	s64 now;
150 	unsigned long flags;
151 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
152 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
153 
154 	spin_lock_irqsave(&register_lock, flags);
155 
156 	now = ixp_systime_read(regs);
157 	now += delta;
158 	ixp_systime_write(regs, now);
159 
160 	spin_unlock_irqrestore(&register_lock, flags);
161 
162 	return 0;
163 }
164 
165 static int ptp_ixp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
166 {
167 	u64 ns;
168 	unsigned long flags;
169 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
170 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
171 
172 	spin_lock_irqsave(&register_lock, flags);
173 
174 	ns = ixp_systime_read(regs);
175 
176 	spin_unlock_irqrestore(&register_lock, flags);
177 
178 	*ts = ns_to_timespec64(ns);
179 	return 0;
180 }
181 
182 static int ptp_ixp_settime(struct ptp_clock_info *ptp,
183 			   const struct timespec64 *ts)
184 {
185 	u64 ns;
186 	unsigned long flags;
187 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
188 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
189 
190 	ns = timespec64_to_ns(ts);
191 
192 	spin_lock_irqsave(&register_lock, flags);
193 
194 	ixp_systime_write(regs, ns);
195 
196 	spin_unlock_irqrestore(&register_lock, flags);
197 
198 	return 0;
199 }
200 
201 static int ptp_ixp_enable(struct ptp_clock_info *ptp,
202 			  struct ptp_clock_request *rq, int on)
203 {
204 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
205 
206 	switch (rq->type) {
207 	case PTP_CLK_REQ_EXTTS:
208 		switch (rq->extts.index) {
209 		case 0:
210 			ixp_clock->exts0_enabled = on ? 1 : 0;
211 			break;
212 		case 1:
213 			ixp_clock->exts1_enabled = on ? 1 : 0;
214 			break;
215 		default:
216 			return -EINVAL;
217 		}
218 		return 0;
219 	default:
220 		break;
221 	}
222 
223 	return -EOPNOTSUPP;
224 }
225 
226 static const struct ptp_clock_info ptp_ixp_caps = {
227 	.owner		= THIS_MODULE,
228 	.name		= "IXP46X timer",
229 	.max_adj	= 66666655,
230 	.n_ext_ts	= N_EXT_TS,
231 	.n_pins		= 0,
232 	.pps		= 0,
233 	.adjfreq	= ptp_ixp_adjfreq,
234 	.adjtime	= ptp_ixp_adjtime,
235 	.gettime64	= ptp_ixp_gettime,
236 	.settime64	= ptp_ixp_settime,
237 	.enable		= ptp_ixp_enable,
238 };
239 
240 /* module operations */
241 
242 static struct ixp_clock ixp_clock;
243 
244 int ixp46x_ptp_find(struct ixp46x_ts_regs *__iomem *regs, int *phc_index)
245 {
246 	*regs = ixp_clock.regs;
247 	*phc_index = ptp_clock_index(ixp_clock.ptp_clock);
248 
249 	if (!ixp_clock.ptp_clock)
250 		return -EPROBE_DEFER;
251 
252 	return 0;
253 }
254 EXPORT_SYMBOL_GPL(ixp46x_ptp_find);
255 
256 /* Called from the registered devm action */
257 static void ptp_ixp_unregister_action(void *d)
258 {
259 	struct ptp_clock *ptp_clock = d;
260 
261 	ptp_clock_unregister(ptp_clock);
262 	ixp_clock.ptp_clock = NULL;
263 }
264 
265 static int ptp_ixp_probe(struct platform_device *pdev)
266 {
267 	struct device *dev = &pdev->dev;
268 	int ret;
269 
270 	ixp_clock.regs = devm_platform_ioremap_resource(pdev, 0);
271 	ixp_clock.master_irq = platform_get_irq(pdev, 0);
272 	ixp_clock.slave_irq = platform_get_irq(pdev, 1);
273 	if (IS_ERR(ixp_clock.regs) ||
274 	    !ixp_clock.master_irq || !ixp_clock.slave_irq)
275 		return -ENXIO;
276 
277 	ixp_clock.caps = ptp_ixp_caps;
278 
279 	ixp_clock.ptp_clock = ptp_clock_register(&ixp_clock.caps, NULL);
280 
281 	if (IS_ERR(ixp_clock.ptp_clock))
282 		return PTR_ERR(ixp_clock.ptp_clock);
283 
284 	ret = devm_add_action_or_reset(dev, ptp_ixp_unregister_action,
285 				       ixp_clock.ptp_clock);
286 	if (ret) {
287 		dev_err(dev, "failed to install clock removal handler\n");
288 		return ret;
289 	}
290 
291 	__raw_writel(DEFAULT_ADDEND, &ixp_clock.regs->addend);
292 	__raw_writel(1, &ixp_clock.regs->trgt_lo);
293 	__raw_writel(0, &ixp_clock.regs->trgt_hi);
294 	__raw_writel(TTIPEND, &ixp_clock.regs->event);
295 
296 	ret = devm_request_irq(dev, ixp_clock.master_irq, isr,
297 			       0, DRIVER, &ixp_clock);
298 	if (ret)
299 		return dev_err_probe(dev, ret,
300 				     "request_irq failed for irq %d\n",
301 				     ixp_clock.master_irq);
302 
303 	ret = devm_request_irq(dev, ixp_clock.slave_irq, isr,
304 			       0, DRIVER, &ixp_clock);
305 	if (ret)
306 		return dev_err_probe(dev, ret,
307 				     "request_irq failed for irq %d\n",
308 				     ixp_clock.slave_irq);
309 
310 	return 0;
311 }
312 
313 static const struct of_device_id ptp_ixp_match[] = {
314 	{
315 		.compatible = "intel,ixp46x-ptp-timer",
316 	},
317 	{ },
318 };
319 
320 static struct platform_driver ptp_ixp_driver = {
321 	.driver = {
322 		.name = "ptp-ixp46x",
323 		.of_match_table = ptp_ixp_match,
324 		.suppress_bind_attrs = true,
325 	},
326 	.probe = ptp_ixp_probe,
327 };
328 module_platform_driver(ptp_ixp_driver);
329 
330 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
331 MODULE_DESCRIPTION("PTP clock using the IXP46X timer");
332 MODULE_LICENSE("GPL");
333