1// SPDX-License-Identifier: GPL-2.0-only
2// Copyright 2017 Broadcom
3
4#include <linux/err.h>
5#include <linux/io.h>
6#include <linux/module.h>
7#include <linux/mod_devicetable.h>
8#include <linux/platform_device.h>
9#include <linux/ptp_clock_kernel.h>
10#include <linux/types.h>
11
12#define DTE_NCO_LOW_TIME_REG 0x00
13#define DTE_NCO_TIME_REG 0x04
14#define DTE_NCO_OVERFLOW_REG 0x08
15#define DTE_NCO_INC_REG 0x0c
16
17#define DTE_NCO_SUM2_MASK 0xffffffff
18#define DTE_NCO_SUM2_SHIFT 4ULL
19
20#define DTE_NCO_SUM3_MASK 0xff
21#define DTE_NCO_SUM3_SHIFT 36ULL
22#define DTE_NCO_SUM3_WR_SHIFT 8
23
24#define DTE_NCO_TS_WRAP_MASK 0xfff
25#define DTE_NCO_TS_WRAP_LSHIFT 32
26
27#define DTE_NCO_INC_DEFAULT 0x80000000
28#define DTE_NUM_REGS_TO_RESTORE 4
29
30/* Full wrap around is 44bits in ns (~4.887 hrs) */
31#define DTE_WRAP_AROUND_NSEC_SHIFT 44
32
33/* 44 bits NCO */
34#define DTE_NCO_MAX_NS 0xFFFFFFFFFFFLL
35
36/* 125MHz with 3.29 reg cfg */
37#define DTE_PPB_ADJ(ppb) (u32)(div64_u64((((u64)abs(ppb) * BIT(28)) +\
38 62500000ULL), 125000000ULL))
39
40/* ptp dte priv structure */
41struct ptp_dte {
42 void __iomem *regs;
43 struct ptp_clock *ptp_clk;
44 struct ptp_clock_info caps;
45 struct device *dev;
46 u32 ts_ovf_last;
47 u32 ts_wrap_cnt;
48 spinlock_t lock;
49 u32 reg_val[DTE_NUM_REGS_TO_RESTORE];
50};
51
52static void dte_write_nco(void __iomem *regs, s64 ns)
53{
54 u32 sum2, sum3;
55
56 sum2 = (u32)((ns >> DTE_NCO_SUM2_SHIFT) & DTE_NCO_SUM2_MASK);
57 /* compensate for ignoring sum1 */
58 if (sum2 != DTE_NCO_SUM2_MASK)
59 sum2++;
60
61 /* to write sum3, bits [15:8] needs to be written */
62 sum3 = (u32)(((ns >> DTE_NCO_SUM3_SHIFT) & DTE_NCO_SUM3_MASK) <<
63 DTE_NCO_SUM3_WR_SHIFT);
64
65 writel(val: 0, addr: (regs + DTE_NCO_LOW_TIME_REG));
66 writel(val: sum2, addr: (regs + DTE_NCO_TIME_REG));
67 writel(val: sum3, addr: (regs + DTE_NCO_OVERFLOW_REG));
68}
69
70static s64 dte_read_nco(void __iomem *regs)
71{
72 u32 sum2, sum3;
73 s64 ns;
74
75 /*
76 * ignoring sum1 (4 bits) gives a 16ns resolution, which
77 * works due to the async register read.
78 */
79 sum3 = readl(addr: regs + DTE_NCO_OVERFLOW_REG) & DTE_NCO_SUM3_MASK;
80 sum2 = readl(addr: regs + DTE_NCO_TIME_REG);
81 ns = ((s64)sum3 << DTE_NCO_SUM3_SHIFT) |
82 ((s64)sum2 << DTE_NCO_SUM2_SHIFT);
83
84 return ns;
85}
86
87static void dte_write_nco_delta(struct ptp_dte *ptp_dte, s64 delta)
88{
89 s64 ns;
90
91 ns = dte_read_nco(regs: ptp_dte->regs);
92
93 /* handle wraparound conditions */
94 if ((delta < 0) && (abs(delta) > ns)) {
95 if (ptp_dte->ts_wrap_cnt) {
96 ns += DTE_NCO_MAX_NS + delta;
97 ptp_dte->ts_wrap_cnt--;
98 } else {
99 ns = 0;
100 }
101 } else {
102 ns += delta;
103 if (ns > DTE_NCO_MAX_NS) {
104 ptp_dte->ts_wrap_cnt++;
105 ns -= DTE_NCO_MAX_NS;
106 }
107 }
108
109 dte_write_nco(regs: ptp_dte->regs, ns);
110
111 ptp_dte->ts_ovf_last = (ns >> DTE_NCO_TS_WRAP_LSHIFT) &
112 DTE_NCO_TS_WRAP_MASK;
113}
114
115static s64 dte_read_nco_with_ovf(struct ptp_dte *ptp_dte)
116{
117 u32 ts_ovf;
118 s64 ns = 0;
119
120 ns = dte_read_nco(regs: ptp_dte->regs);
121
122 /*Timestamp overflow: 8 LSB bits of sum3, 4 MSB bits of sum2 */
123 ts_ovf = (ns >> DTE_NCO_TS_WRAP_LSHIFT) & DTE_NCO_TS_WRAP_MASK;
124
125 /* Check for wrap around */
126 if (ts_ovf < ptp_dte->ts_ovf_last)
127 ptp_dte->ts_wrap_cnt++;
128
129 ptp_dte->ts_ovf_last = ts_ovf;
130
131 /* adjust for wraparounds */
132 ns += (s64)(BIT_ULL(DTE_WRAP_AROUND_NSEC_SHIFT) * ptp_dte->ts_wrap_cnt);
133
134 return ns;
135}
136
137static int ptp_dte_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
138{
139 s32 ppb = scaled_ppm_to_ppb(ppm: scaled_ppm);
140 u32 nco_incr;
141 unsigned long flags;
142 struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
143
144 if (abs(ppb) > ptp_dte->caps.max_adj) {
145 dev_err(ptp_dte->dev, "ppb adj too big\n");
146 return -EINVAL;
147 }
148
149 if (ppb < 0)
150 nco_incr = DTE_NCO_INC_DEFAULT - DTE_PPB_ADJ(ppb);
151 else
152 nco_incr = DTE_NCO_INC_DEFAULT + DTE_PPB_ADJ(ppb);
153
154 spin_lock_irqsave(&ptp_dte->lock, flags);
155 writel(val: nco_incr, addr: ptp_dte->regs + DTE_NCO_INC_REG);
156 spin_unlock_irqrestore(lock: &ptp_dte->lock, flags);
157
158 return 0;
159}
160
161static int ptp_dte_adjtime(struct ptp_clock_info *ptp, s64 delta)
162{
163 unsigned long flags;
164 struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
165
166 spin_lock_irqsave(&ptp_dte->lock, flags);
167 dte_write_nco_delta(ptp_dte, delta);
168 spin_unlock_irqrestore(lock: &ptp_dte->lock, flags);
169
170 return 0;
171}
172
173static int ptp_dte_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
174{
175 unsigned long flags;
176 struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
177
178 spin_lock_irqsave(&ptp_dte->lock, flags);
179 *ts = ns_to_timespec64(nsec: dte_read_nco_with_ovf(ptp_dte));
180 spin_unlock_irqrestore(lock: &ptp_dte->lock, flags);
181
182 return 0;
183}
184
185static int ptp_dte_settime(struct ptp_clock_info *ptp,
186 const struct timespec64 *ts)
187{
188 unsigned long flags;
189 struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
190
191 spin_lock_irqsave(&ptp_dte->lock, flags);
192
193 /* Disable nco increment */
194 writel(val: 0, addr: ptp_dte->regs + DTE_NCO_INC_REG);
195
196 dte_write_nco(regs: ptp_dte->regs, ns: timespec64_to_ns(ts));
197
198 /* reset overflow and wrap counter */
199 ptp_dte->ts_ovf_last = 0;
200 ptp_dte->ts_wrap_cnt = 0;
201
202 /* Enable nco increment */
203 writel(DTE_NCO_INC_DEFAULT, addr: ptp_dte->regs + DTE_NCO_INC_REG);
204
205 spin_unlock_irqrestore(lock: &ptp_dte->lock, flags);
206
207 return 0;
208}
209
210static int ptp_dte_enable(struct ptp_clock_info *ptp,
211 struct ptp_clock_request *rq, int on)
212{
213 return -EOPNOTSUPP;
214}
215
216static const struct ptp_clock_info ptp_dte_caps = {
217 .owner = THIS_MODULE,
218 .name = "DTE PTP timer",
219 .max_adj = 50000000,
220 .n_ext_ts = 0,
221 .n_pins = 0,
222 .pps = 0,
223 .adjfine = ptp_dte_adjfine,
224 .adjtime = ptp_dte_adjtime,
225 .gettime64 = ptp_dte_gettime,
226 .settime64 = ptp_dte_settime,
227 .enable = ptp_dte_enable,
228};
229
230static int ptp_dte_probe(struct platform_device *pdev)
231{
232 struct ptp_dte *ptp_dte;
233 struct device *dev = &pdev->dev;
234
235 ptp_dte = devm_kzalloc(dev, size: sizeof(struct ptp_dte), GFP_KERNEL);
236 if (!ptp_dte)
237 return -ENOMEM;
238
239 ptp_dte->regs = devm_platform_ioremap_resource(pdev, index: 0);
240 if (IS_ERR(ptr: ptp_dte->regs))
241 return PTR_ERR(ptr: ptp_dte->regs);
242
243 spin_lock_init(&ptp_dte->lock);
244
245 ptp_dte->dev = dev;
246 ptp_dte->caps = ptp_dte_caps;
247 ptp_dte->ptp_clk = ptp_clock_register(info: &ptp_dte->caps, parent: &pdev->dev);
248 if (IS_ERR(ptr: ptp_dte->ptp_clk)) {
249 dev_err(dev,
250 "%s: Failed to register ptp clock\n", __func__);
251 return PTR_ERR(ptr: ptp_dte->ptp_clk);
252 }
253
254 platform_set_drvdata(pdev, data: ptp_dte);
255
256 dev_info(dev, "ptp clk probe done\n");
257
258 return 0;
259}
260
261static int ptp_dte_remove(struct platform_device *pdev)
262{
263 struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
264 u8 i;
265
266 ptp_clock_unregister(ptp: ptp_dte->ptp_clk);
267
268 for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++)
269 writel(val: 0, addr: ptp_dte->regs + (i * sizeof(u32)));
270
271 return 0;
272}
273
274#ifdef CONFIG_PM_SLEEP
275static int ptp_dte_suspend(struct device *dev)
276{
277 struct ptp_dte *ptp_dte = dev_get_drvdata(dev);
278 u8 i;
279
280 for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
281 ptp_dte->reg_val[i] =
282 readl(addr: ptp_dte->regs + (i * sizeof(u32)));
283 }
284
285 /* disable the nco */
286 writel(val: 0, addr: ptp_dte->regs + DTE_NCO_INC_REG);
287
288 return 0;
289}
290
291static int ptp_dte_resume(struct device *dev)
292{
293 struct ptp_dte *ptp_dte = dev_get_drvdata(dev);
294 u8 i;
295
296 for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
297 if ((i * sizeof(u32)) != DTE_NCO_OVERFLOW_REG)
298 writel(val: ptp_dte->reg_val[i],
299 addr: (ptp_dte->regs + (i * sizeof(u32))));
300 else
301 writel(val: ((ptp_dte->reg_val[i] &
302 DTE_NCO_SUM3_MASK) << DTE_NCO_SUM3_WR_SHIFT),
303 addr: (ptp_dte->regs + (i * sizeof(u32))));
304 }
305
306 return 0;
307}
308
309static const struct dev_pm_ops ptp_dte_pm_ops = {
310 .suspend = ptp_dte_suspend,
311 .resume = ptp_dte_resume
312};
313
314#define PTP_DTE_PM_OPS (&ptp_dte_pm_ops)
315#else
316#define PTP_DTE_PM_OPS NULL
317#endif
318
319static const struct of_device_id ptp_dte_of_match[] = {
320 { .compatible = "brcm,ptp-dte", },
321 {},
322};
323MODULE_DEVICE_TABLE(of, ptp_dte_of_match);
324
325static struct platform_driver ptp_dte_driver = {
326 .driver = {
327 .name = "ptp-dte",
328 .pm = PTP_DTE_PM_OPS,
329 .of_match_table = ptp_dte_of_match,
330 },
331 .probe = ptp_dte_probe,
332 .remove = ptp_dte_remove,
333};
334module_platform_driver(ptp_dte_driver);
335
336MODULE_AUTHOR("Broadcom");
337MODULE_DESCRIPTION("Broadcom DTE PTP Clock driver");
338MODULE_LICENSE("GPL v2");
339

source code of linux/drivers/ptp/ptp_dte.c