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_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
124 {
125 	u32 addend;
126 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
127 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
128 
129 	addend = adjust_by_scaled_ppm(DEFAULT_ADDEND, scaled_ppm);
130 
131 	__raw_writel(addend, &regs->addend);
132 
133 	return 0;
134 }
135 
136 static int ptp_ixp_adjtime(struct ptp_clock_info *ptp, s64 delta)
137 {
138 	s64 now;
139 	unsigned long flags;
140 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
141 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
142 
143 	spin_lock_irqsave(&register_lock, flags);
144 
145 	now = ixp_systime_read(regs);
146 	now += delta;
147 	ixp_systime_write(regs, now);
148 
149 	spin_unlock_irqrestore(&register_lock, flags);
150 
151 	return 0;
152 }
153 
154 static int ptp_ixp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
155 {
156 	u64 ns;
157 	unsigned long flags;
158 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
159 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
160 
161 	spin_lock_irqsave(&register_lock, flags);
162 
163 	ns = ixp_systime_read(regs);
164 
165 	spin_unlock_irqrestore(&register_lock, flags);
166 
167 	*ts = ns_to_timespec64(ns);
168 	return 0;
169 }
170 
171 static int ptp_ixp_settime(struct ptp_clock_info *ptp,
172 			   const struct timespec64 *ts)
173 {
174 	u64 ns;
175 	unsigned long flags;
176 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
177 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
178 
179 	ns = timespec64_to_ns(ts);
180 
181 	spin_lock_irqsave(&register_lock, flags);
182 
183 	ixp_systime_write(regs, ns);
184 
185 	spin_unlock_irqrestore(&register_lock, flags);
186 
187 	return 0;
188 }
189 
190 static int ptp_ixp_enable(struct ptp_clock_info *ptp,
191 			  struct ptp_clock_request *rq, int on)
192 {
193 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
194 
195 	switch (rq->type) {
196 	case PTP_CLK_REQ_EXTTS:
197 		switch (rq->extts.index) {
198 		case 0:
199 			ixp_clock->exts0_enabled = on ? 1 : 0;
200 			break;
201 		case 1:
202 			ixp_clock->exts1_enabled = on ? 1 : 0;
203 			break;
204 		default:
205 			return -EINVAL;
206 		}
207 		return 0;
208 	default:
209 		break;
210 	}
211 
212 	return -EOPNOTSUPP;
213 }
214 
215 static const struct ptp_clock_info ptp_ixp_caps = {
216 	.owner		= THIS_MODULE,
217 	.name		= "IXP46X timer",
218 	.max_adj	= 66666655,
219 	.n_ext_ts	= N_EXT_TS,
220 	.n_pins		= 0,
221 	.pps		= 0,
222 	.adjfine	= ptp_ixp_adjfine,
223 	.adjtime	= ptp_ixp_adjtime,
224 	.gettime64	= ptp_ixp_gettime,
225 	.settime64	= ptp_ixp_settime,
226 	.enable		= ptp_ixp_enable,
227 };
228 
229 /* module operations */
230 
231 static struct ixp_clock ixp_clock;
232 
233 int ixp46x_ptp_find(struct ixp46x_ts_regs *__iomem *regs, int *phc_index)
234 {
235 	*regs = ixp_clock.regs;
236 	*phc_index = ptp_clock_index(ixp_clock.ptp_clock);
237 
238 	if (!ixp_clock.ptp_clock)
239 		return -EPROBE_DEFER;
240 
241 	return 0;
242 }
243 EXPORT_SYMBOL_GPL(ixp46x_ptp_find);
244 
245 /* Called from the registered devm action */
246 static void ptp_ixp_unregister_action(void *d)
247 {
248 	struct ptp_clock *ptp_clock = d;
249 
250 	ptp_clock_unregister(ptp_clock);
251 	ixp_clock.ptp_clock = NULL;
252 }
253 
254 static int ptp_ixp_probe(struct platform_device *pdev)
255 {
256 	struct device *dev = &pdev->dev;
257 	int ret;
258 
259 	ixp_clock.regs = devm_platform_ioremap_resource(pdev, 0);
260 	ixp_clock.master_irq = platform_get_irq(pdev, 0);
261 	ixp_clock.slave_irq = platform_get_irq(pdev, 1);
262 	if (IS_ERR(ixp_clock.regs) ||
263 	    ixp_clock.master_irq < 0 || ixp_clock.slave_irq < 0)
264 		return -ENXIO;
265 
266 	ixp_clock.caps = ptp_ixp_caps;
267 
268 	ixp_clock.ptp_clock = ptp_clock_register(&ixp_clock.caps, NULL);
269 
270 	if (IS_ERR(ixp_clock.ptp_clock))
271 		return PTR_ERR(ixp_clock.ptp_clock);
272 
273 	ret = devm_add_action_or_reset(dev, ptp_ixp_unregister_action,
274 				       ixp_clock.ptp_clock);
275 	if (ret) {
276 		dev_err(dev, "failed to install clock removal handler\n");
277 		return ret;
278 	}
279 
280 	__raw_writel(DEFAULT_ADDEND, &ixp_clock.regs->addend);
281 	__raw_writel(1, &ixp_clock.regs->trgt_lo);
282 	__raw_writel(0, &ixp_clock.regs->trgt_hi);
283 	__raw_writel(TTIPEND, &ixp_clock.regs->event);
284 
285 	ret = devm_request_irq(dev, ixp_clock.master_irq, isr,
286 			       0, DRIVER, &ixp_clock);
287 	if (ret)
288 		return dev_err_probe(dev, ret,
289 				     "request_irq failed for irq %d\n",
290 				     ixp_clock.master_irq);
291 
292 	ret = devm_request_irq(dev, ixp_clock.slave_irq, isr,
293 			       0, DRIVER, &ixp_clock);
294 	if (ret)
295 		return dev_err_probe(dev, ret,
296 				     "request_irq failed for irq %d\n",
297 				     ixp_clock.slave_irq);
298 
299 	return 0;
300 }
301 
302 static const struct of_device_id ptp_ixp_match[] = {
303 	{
304 		.compatible = "intel,ixp46x-ptp-timer",
305 	},
306 	{ },
307 };
308 
309 static struct platform_driver ptp_ixp_driver = {
310 	.driver = {
311 		.name = "ptp-ixp46x",
312 		.of_match_table = ptp_ixp_match,
313 		.suppress_bind_attrs = true,
314 	},
315 	.probe = ptp_ixp_probe,
316 };
317 module_platform_driver(ptp_ixp_driver);
318 
319 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
320 MODULE_DESCRIPTION("PTP clock using the IXP46X timer");
321 MODULE_LICENSE("GPL");
322