drivers/net/ethernet/xscale/ptp_ixp46x.c

   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/err.h>
   9 #include <linux/gpio.h>
  10 #include <linux/init.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/io.h>
  13 #include <linux/irq.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16
  17 #include <linux/ptp_clock_kernel.h>
  18
  19 #include "ixp46x_ts.h"
  20
  21 #define DRIVER          "ptp_ixp46x"
  22 #define N_EXT_TS        2
  23 #define MASTER_GPIO     8
  24 #define MASTER_IRQ      25
  25 #define SLAVE_GPIO      7
  26 #define SLAVE_IRQ       24
  27
  28 struct ixp_clock {
  29         struct ixp46x_ts_regs *regs;
  30         struct ptp_clock *ptp_clock;
  31         struct ptp_clock_info caps;
  32         int exts0_enabled;
  33         int exts1_enabled;
  34 };
  35
  36 DEFINE_SPINLOCK(register_lock);
  37
  38 /*
  39  * Register access functions
  40  */
  41
  42 static u64 ixp_systime_read(struct ixp46x_ts_regs *regs)
  43 {
  44         u64 ns;
  45         u32 lo, hi;
  46
  47         lo = __raw_readl(&regs->systime_lo);
  48         hi = __raw_readl(&regs->systime_hi);
  49
  50         ns = ((u64) hi) << 32;
  51         ns |= lo;
  52         ns <<= TICKS_NS_SHIFT;
  53
  54         return ns;
  55 }
  56
  57 static void ixp_systime_write(struct ixp46x_ts_regs *regs, u64 ns)
  58 {
  59         u32 hi, lo;
  60
  61         ns >>= TICKS_NS_SHIFT;
  62         hi = ns >> 32;
  63         lo = ns & 0xffffffff;
  64
  65         __raw_writel(lo, &regs->systime_lo);
  66         __raw_writel(hi, &regs->systime_hi);
  67 }
  68
  69 /*
  70  * Interrupt service routine
  71  */
  72
  73 static irqreturn_t isr(int irq, void *priv)
  74 {
  75         struct ixp_clock *ixp_clock = priv;
  76         struct ixp46x_ts_regs *regs = ixp_clock->regs;
  77         struct ptp_clock_event event;
  78         u32 ack = 0, lo, hi, val;
  79
  80         val = __raw_readl(&regs->event);
  81
  82         if (val & TSER_SNS) {
  83                 ack |= TSER_SNS;
  84                 if (ixp_clock->exts0_enabled) {
  85                         hi = __raw_readl(&regs->asms_hi);
  86                         lo = __raw_readl(&regs->asms_lo);
  87                         event.type = PTP_CLOCK_EXTTS;
  88                         event.index = 0;
  89                         event.timestamp = ((u64) hi) << 32;
  90                         event.timestamp |= lo;
  91                         event.timestamp <<= TICKS_NS_SHIFT;
  92                         ptp_clock_event(ixp_clock->ptp_clock, &event);
  93                 }
  94         }
  95
  96         if (val & TSER_SNM) {
  97                 ack |= TSER_SNM;
  98                 if (ixp_clock->exts1_enabled) {
  99                         hi = __raw_readl(&regs->amms_hi);
 100                         lo = __raw_readl(&regs->amms_lo);
 101                         event.type = PTP_CLOCK_EXTTS;
 102                         event.index = 1;
 103                         event.timestamp = ((u64) hi) << 32;
 104                         event.timestamp |= lo;
 105                         event.timestamp <<= TICKS_NS_SHIFT;
 106                         ptp_clock_event(ixp_clock->ptp_clock, &event);
 107                 }
 108         }
 109
 110         if (val & TTIPEND)
 111                 ack |= TTIPEND; /* this bit seems to be always set */
 112
 113         if (ack) {
 114                 __raw_writel(ack, &regs->event);
 115                 return IRQ_HANDLED;
 116         } else
 117                 return IRQ_NONE;
 118 }
 119
 120 /*
 121  * PTP clock operations
 122  */
 123
 124 static int ptp_ixp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
 125 {
 126         u64 adj;
 127         u32 diff, addend;
 128         int neg_adj = 0;
 129         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 130         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 131
 132         if (ppb < 0) {
 133                 neg_adj = 1;
 134                 ppb = -ppb;
 135         }
 136         addend = DEFAULT_ADDEND;
 137         adj = addend;
 138         adj *= ppb;
 139         diff = div_u64(adj, 1000000000ULL);
 140
 141         addend = neg_adj ? addend - diff : addend + diff;
 142
 143         __raw_writel(addend, &regs->addend);
 144
 145         return 0;
 146 }
 147
 148 static int ptp_ixp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 149 {
 150         s64 now;
 151         unsigned long flags;
 152         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 153         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 154
 155         spin_lock_irqsave(&register_lock, flags);
 156
 157         now = ixp_systime_read(regs);
 158         now += delta;
 159         ixp_systime_write(regs, now);
 160
 161         spin_unlock_irqrestore(&register_lock, flags);
 162
 163         return 0;
 164 }
 165
 166 static int ptp_ixp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 167 {
 168         u64 ns;
 169         unsigned long flags;
 170         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 171         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 172
 173         spin_lock_irqsave(&register_lock, flags);
 174
 175         ns = ixp_systime_read(regs);
 176
 177         spin_unlock_irqrestore(&register_lock, flags);
 178
 179         *ts = ns_to_timespec64(ns);
 180         return 0;
 181 }
 182
 183 static int ptp_ixp_settime(struct ptp_clock_info *ptp,
 184                            const struct timespec64 *ts)
 185 {
 186         u64 ns;
 187         unsigned long flags;
 188         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 189         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 190
 191         ns = timespec64_to_ns(ts);
 192
 193         spin_lock_irqsave(&register_lock, flags);
 194
 195         ixp_systime_write(regs, ns);
 196
 197         spin_unlock_irqrestore(&register_lock, flags);
 198
 199         return 0;
 200 }
 201
 202 static int ptp_ixp_enable(struct ptp_clock_info *ptp,
 203                           struct ptp_clock_request *rq, int on)
 204 {
 205         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 206
 207         switch (rq->type) {
 208         case PTP_CLK_REQ_EXTTS:
 209                 switch (rq->extts.index) {
 210                 case 0:
 211                         ixp_clock->exts0_enabled = on ? 1 : 0;
 212                         break;
 213                 case 1:
 214                         ixp_clock->exts1_enabled = on ? 1 : 0;
 215                         break;
 216                 default:
 217                         return -EINVAL;
 218                 }
 219                 return 0;
 220         default:
 221                 break;
 222         }
 223
 224         return -EOPNOTSUPP;
 225 }
 226
 227 static const struct ptp_clock_info ptp_ixp_caps = {
 228         .owner          = THIS_MODULE,
 229         .name           = "IXP46X timer",
 230         .max_adj        = 66666655,
 231         .n_ext_ts       = N_EXT_TS,
 232         .n_pins         = 0,
 233         .pps            = 0,
 234         .adjfreq        = ptp_ixp_adjfreq,
 235         .adjtime        = ptp_ixp_adjtime,
 236         .gettime64      = ptp_ixp_gettime,
 237         .settime64      = ptp_ixp_settime,
 238         .enable         = ptp_ixp_enable,
 239 };
 240
 241 /* module operations */
 242
 243 static struct ixp_clock ixp_clock;
 244
 245 static int setup_interrupt(int gpio)
 246 {
 247         int irq;
 248         int err;
 249
 250         err = gpio_request(gpio, "ixp4-ptp");
 251         if (err)
 252                 return err;
 253
 254         err = gpio_direction_input(gpio);
 255         if (err)
 256                 return err;
 257
 258         irq = gpio_to_irq(gpio);
 259         if (irq < 0)
 260                 return irq;
 261
 262         err = irq_set_irq_type(irq, IRQF_TRIGGER_FALLING);
 263         if (err) {
 264                 pr_err("cannot set trigger type for irq %d\n", irq);
 265                 return err;
 266         }
 267
 268         err = request_irq(irq, isr, 0, DRIVER, &ixp_clock);
 269         if (err) {
 270                 pr_err("request_irq failed for irq %d\n", irq);
 271                 return err;
 272         }
 273
 274         return irq;
 275 }
 276
 277 static void __exit ptp_ixp_exit(void)
 278 {
 279         free_irq(MASTER_IRQ, &ixp_clock);
 280         free_irq(SLAVE_IRQ, &ixp_clock);
 281         ixp46x_phc_index = -1;
 282         ptp_clock_unregister(ixp_clock.ptp_clock);
 283 }
 284
 285 static int __init ptp_ixp_init(void)
 286 {
 287         if (!cpu_is_ixp46x())
 288                 return -ENODEV;
 289
 290         ixp_clock.regs =
 291                 (struct ixp46x_ts_regs __iomem *) IXP4XX_TIMESYNC_BASE_VIRT;
 292
 293         ixp_clock.caps = ptp_ixp_caps;
 294
 295         ixp_clock.ptp_clock = ptp_clock_register(&ixp_clock.caps, NULL);
 296
 297         if (IS_ERR(ixp_clock.ptp_clock))
 298                 return PTR_ERR(ixp_clock.ptp_clock);
 299
 300         ixp46x_phc_index = ptp_clock_index(ixp_clock.ptp_clock);
 301
 302         __raw_writel(DEFAULT_ADDEND, &ixp_clock.regs->addend);
 303         __raw_writel(1, &ixp_clock.regs->trgt_lo);
 304         __raw_writel(0, &ixp_clock.regs->trgt_hi);
 305         __raw_writel(TTIPEND, &ixp_clock.regs->event);
 306
 307         if (MASTER_IRQ != setup_interrupt(MASTER_GPIO)) {
 308                 pr_err("failed to setup gpio %d as irq\n", MASTER_GPIO);
 309                 goto no_master;
 310         }
 311         if (SLAVE_IRQ != setup_interrupt(SLAVE_GPIO)) {
 312                 pr_err("failed to setup gpio %d as irq\n", SLAVE_GPIO);
 313                 goto no_slave;
 314         }
 315
 316         return 0;
 317 no_slave:
 318         free_irq(MASTER_IRQ, &ixp_clock);
 319 no_master:
 320         ptp_clock_unregister(ixp_clock.ptp_clock);
 321         return -ENODEV;
 322 }
 323
 324 module_init(ptp_ixp_init);
 325 module_exit(ptp_ixp_exit);
 326
 327 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 328 MODULE_DESCRIPTION("PTP clock using the IXP46X timer");
 329 MODULE_LICENSE("GPL");