drivers/ptp/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 #include <mach/ixp46x_ts.h>
  19
  20 #define DRIVER          "ptp_ixp46x"
  21 #define N_EXT_TS        2
  22 #define MASTER_GPIO     8
  23 #define MASTER_IRQ      25
  24 #define SLAVE_GPIO      7
  25 #define SLAVE_IRQ       24
  26
  27 struct ixp_clock {
  28         struct ixp46x_ts_regs *regs;
  29         struct ptp_clock *ptp_clock;
  30         struct ptp_clock_info caps;
  31         int exts0_enabled;
  32         int exts1_enabled;
  33 };
  34
  35 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 static int setup_interrupt(int gpio)
 245 {
 246         int irq;
 247         int err;
 248
 249         err = gpio_request(gpio, "ixp4-ptp");
 250         if (err)
 251                 return err;
 252
 253         err = gpio_direction_input(gpio);
 254         if (err)
 255                 return err;
 256
 257         irq = gpio_to_irq(gpio);
 258         if (irq < 0)
 259                 return irq;
 260
 261         err = irq_set_irq_type(irq, IRQF_TRIGGER_FALLING);
 262         if (err) {
 263                 pr_err("cannot set trigger type for irq %d\n", irq);
 264                 return err;
 265         }
 266
 267         err = request_irq(irq, isr, 0, DRIVER, &ixp_clock);
 268         if (err) {
 269                 pr_err("request_irq failed for irq %d\n", irq);
 270                 return err;
 271         }
 272
 273         return irq;
 274 }
 275
 276 static void __exit ptp_ixp_exit(void)
 277 {
 278         free_irq(MASTER_IRQ, &ixp_clock);
 279         free_irq(SLAVE_IRQ, &ixp_clock);
 280         ixp46x_phc_index = -1;
 281         ptp_clock_unregister(ixp_clock.ptp_clock);
 282 }
 283
 284 static int __init ptp_ixp_init(void)
 285 {
 286         if (!cpu_is_ixp46x())
 287                 return -ENODEV;
 288
 289         ixp_clock.regs =
 290                 (struct ixp46x_ts_regs __iomem *) IXP4XX_TIMESYNC_BASE_VIRT;
 291
 292         ixp_clock.caps = ptp_ixp_caps;
 293
 294         ixp_clock.ptp_clock = ptp_clock_register(&ixp_clock.caps, NULL);
 295
 296         if (IS_ERR(ixp_clock.ptp_clock))
 297                 return PTR_ERR(ixp_clock.ptp_clock);
 298
 299         ixp46x_phc_index = ptp_clock_index(ixp_clock.ptp_clock);
 300
 301         __raw_writel(DEFAULT_ADDEND, &ixp_clock.regs->addend);
 302         __raw_writel(1, &ixp_clock.regs->trgt_lo);
 303         __raw_writel(0, &ixp_clock.regs->trgt_hi);
 304         __raw_writel(TTIPEND, &ixp_clock.regs->event);
 305
 306         if (MASTER_IRQ != setup_interrupt(MASTER_GPIO)) {
 307                 pr_err("failed to setup gpio %d as irq\n", MASTER_GPIO);
 308                 goto no_master;
 309         }
 310         if (SLAVE_IRQ != setup_interrupt(SLAVE_GPIO)) {
 311                 pr_err("failed to setup gpio %d as irq\n", SLAVE_GPIO);
 312                 goto no_slave;
 313         }
 314
 315         return 0;
 316 no_slave:
 317         free_irq(MASTER_IRQ, &ixp_clock);
 318 no_master:
 319         ptp_clock_unregister(ixp_clock.ptp_clock);
 320         return -ENODEV;
 321 }
 322
 323 module_init(ptp_ixp_init);
 324 module_exit(ptp_ixp_exit);
 325
 326 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 327 MODULE_DESCRIPTION("PTP clock using the IXP46X timer");
 328 MODULE_LICENSE("GPL");