drivers/ptp/ptp_ixp46x.c

   1 /*
   2  * PTP 1588 clock using the IXP46X
   3  *
   4  * Copyright (C) 2010 OMICRON electronics GmbH
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20 #include <linux/device.h>
  21 #include <linux/err.h>
  22 #include <linux/gpio.h>
  23 #include <linux/init.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/io.h>
  26 #include <linux/irq.h>
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29
  30 #include <linux/ptp_clock_kernel.h>
  31 #include <mach/ixp46x_ts.h>
  32
  33 #define DRIVER          "ptp_ixp46x"
  34 #define N_EXT_TS        2
  35 #define MASTER_GPIO     8
  36 #define MASTER_IRQ      25
  37 #define SLAVE_GPIO      7
  38 #define SLAVE_IRQ       24
  39
  40 struct ixp_clock {
  41         struct ixp46x_ts_regs *regs;
  42         struct ptp_clock *ptp_clock;
  43         struct ptp_clock_info caps;
  44         int exts0_enabled;
  45         int exts1_enabled;
  46 };
  47
  48 DEFINE_SPINLOCK(register_lock);
  49
  50 /*
  51  * Register access functions
  52  */
  53
  54 static u64 ixp_systime_read(struct ixp46x_ts_regs *regs)
  55 {
  56         u64 ns;
  57         u32 lo, hi;
  58
  59         lo = __raw_readl(&regs->systime_lo);
  60         hi = __raw_readl(&regs->systime_hi);
  61
  62         ns = ((u64) hi) << 32;
  63         ns |= lo;
  64         ns <<= TICKS_NS_SHIFT;
  65
  66         return ns;
  67 }
  68
  69 static void ixp_systime_write(struct ixp46x_ts_regs *regs, u64 ns)
  70 {
  71         u32 hi, lo;
  72
  73         ns >>= TICKS_NS_SHIFT;
  74         hi = ns >> 32;
  75         lo = ns & 0xffffffff;
  76
  77         __raw_writel(lo, &regs->systime_lo);
  78         __raw_writel(hi, &regs->systime_hi);
  79 }
  80
  81 /*
  82  * Interrupt service routine
  83  */
  84
  85 static irqreturn_t isr(int irq, void *priv)
  86 {
  87         struct ixp_clock *ixp_clock = priv;
  88         struct ixp46x_ts_regs *regs = ixp_clock->regs;
  89         struct ptp_clock_event event;
  90         u32 ack = 0, lo, hi, val;
  91
  92         val = __raw_readl(&regs->event);
  93
  94         if (val & TSER_SNS) {
  95                 ack |= TSER_SNS;
  96                 if (ixp_clock->exts0_enabled) {
  97                         hi = __raw_readl(&regs->asms_hi);
  98                         lo = __raw_readl(&regs->asms_lo);
  99                         event.type = PTP_CLOCK_EXTTS;
 100                         event.index = 0;
 101                         event.timestamp = ((u64) hi) << 32;
 102                         event.timestamp |= lo;
 103                         event.timestamp <<= TICKS_NS_SHIFT;
 104                         ptp_clock_event(ixp_clock->ptp_clock, &event);
 105                 }
 106         }
 107
 108         if (val & TSER_SNM) {
 109                 ack |= TSER_SNM;
 110                 if (ixp_clock->exts1_enabled) {
 111                         hi = __raw_readl(&regs->amms_hi);
 112                         lo = __raw_readl(&regs->amms_lo);
 113                         event.type = PTP_CLOCK_EXTTS;
 114                         event.index = 1;
 115                         event.timestamp = ((u64) hi) << 32;
 116                         event.timestamp |= lo;
 117                         event.timestamp <<= TICKS_NS_SHIFT;
 118                         ptp_clock_event(ixp_clock->ptp_clock, &event);
 119                 }
 120         }
 121
 122         if (val & TTIPEND)
 123                 ack |= TTIPEND; /* this bit seems to be always set */
 124
 125         if (ack) {
 126                 __raw_writel(ack, &regs->event);
 127                 return IRQ_HANDLED;
 128         } else
 129                 return IRQ_NONE;
 130 }
 131
 132 /*
 133  * PTP clock operations
 134  */
 135
 136 static int ptp_ixp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
 137 {
 138         u64 adj;
 139         u32 diff, addend;
 140         int neg_adj = 0;
 141         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 142         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 143
 144         if (ppb < 0) {
 145                 neg_adj = 1;
 146                 ppb = -ppb;
 147         }
 148         addend = DEFAULT_ADDEND;
 149         adj = addend;
 150         adj *= ppb;
 151         diff = div_u64(adj, 1000000000ULL);
 152
 153         addend = neg_adj ? addend - diff : addend + diff;
 154
 155         __raw_writel(addend, &regs->addend);
 156
 157         return 0;
 158 }
 159
 160 static int ptp_ixp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 161 {
 162         s64 now;
 163         unsigned long flags;
 164         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 165         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 166
 167         spin_lock_irqsave(&register_lock, flags);
 168
 169         now = ixp_systime_read(regs);
 170         now += delta;
 171         ixp_systime_write(regs, now);
 172
 173         spin_unlock_irqrestore(&register_lock, flags);
 174
 175         return 0;
 176 }
 177
 178 static int ptp_ixp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 179 {
 180         u64 ns;
 181         unsigned long flags;
 182         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 183         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 184
 185         spin_lock_irqsave(&register_lock, flags);
 186
 187         ns = ixp_systime_read(regs);
 188
 189         spin_unlock_irqrestore(&register_lock, flags);
 190
 191         *ts = ns_to_timespec64(ns);
 192         return 0;
 193 }
 194
 195 static int ptp_ixp_settime(struct ptp_clock_info *ptp,
 196                            const struct timespec64 *ts)
 197 {
 198         u64 ns;
 199         unsigned long flags;
 200         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 201         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 202
 203         ns = timespec64_to_ns(ts);
 204
 205         spin_lock_irqsave(&register_lock, flags);
 206
 207         ixp_systime_write(regs, ns);
 208
 209         spin_unlock_irqrestore(&register_lock, flags);
 210
 211         return 0;
 212 }
 213
 214 static int ptp_ixp_enable(struct ptp_clock_info *ptp,
 215                           struct ptp_clock_request *rq, int on)
 216 {
 217         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 218
 219         switch (rq->type) {
 220         case PTP_CLK_REQ_EXTTS:
 221                 switch (rq->extts.index) {
 222                 case 0:
 223                         ixp_clock->exts0_enabled = on ? 1 : 0;
 224                         break;
 225                 case 1:
 226                         ixp_clock->exts1_enabled = on ? 1 : 0;
 227                         break;
 228                 default:
 229                         return -EINVAL;
 230                 }
 231                 return 0;
 232         default:
 233                 break;
 234         }
 235
 236         return -EOPNOTSUPP;
 237 }
 238
 239 static struct ptp_clock_info ptp_ixp_caps = {
 240         .owner          = THIS_MODULE,
 241         .name           = "IXP46X timer",
 242         .max_adj        = 66666655,
 243         .n_ext_ts       = N_EXT_TS,
 244         .n_pins         = 0,
 245         .pps            = 0,
 246         .adjfreq        = ptp_ixp_adjfreq,
 247         .adjtime        = ptp_ixp_adjtime,
 248         .gettime64      = ptp_ixp_gettime,
 249         .settime64      = ptp_ixp_settime,
 250         .enable         = ptp_ixp_enable,
 251 };
 252
 253 /* module operations */
 254
 255 static struct ixp_clock ixp_clock;
 256
 257 static int setup_interrupt(int gpio)
 258 {
 259         int irq;
 260         int err;
 261
 262         err = gpio_request(gpio, "ixp4-ptp");
 263         if (err)
 264                 return err;
 265
 266         err = gpio_direction_input(gpio);
 267         if (err)
 268                 return err;
 269
 270         irq = gpio_to_irq(gpio);
 271         if (irq < 0)
 272                 return irq;
 273
 274         err = irq_set_irq_type(irq, IRQF_TRIGGER_FALLING);
 275         if (err) {
 276                 pr_err("cannot set trigger type for irq %d\n", irq);
 277                 return err;
 278         }
 279
 280         err = request_irq(irq, isr, 0, DRIVER, &ixp_clock);
 281         if (err) {
 282                 pr_err("request_irq failed for irq %d\n", irq);
 283                 return err;
 284         }
 285
 286         return irq;
 287 }
 288
 289 static void __exit ptp_ixp_exit(void)
 290 {
 291         free_irq(MASTER_IRQ, &ixp_clock);
 292         free_irq(SLAVE_IRQ, &ixp_clock);
 293         ixp46x_phc_index = -1;
 294         ptp_clock_unregister(ixp_clock.ptp_clock);
 295 }
 296
 297 static int __init ptp_ixp_init(void)
 298 {
 299         if (!cpu_is_ixp46x())
 300                 return -ENODEV;
 301
 302         ixp_clock.regs =
 303                 (struct ixp46x_ts_regs __iomem *) IXP4XX_TIMESYNC_BASE_VIRT;
 304
 305         ixp_clock.caps = ptp_ixp_caps;
 306
 307         ixp_clock.ptp_clock = ptp_clock_register(&ixp_clock.caps, NULL);
 308
 309         if (IS_ERR(ixp_clock.ptp_clock))
 310                 return PTR_ERR(ixp_clock.ptp_clock);
 311
 312         ixp46x_phc_index = ptp_clock_index(ixp_clock.ptp_clock);
 313
 314         __raw_writel(DEFAULT_ADDEND, &ixp_clock.regs->addend);
 315         __raw_writel(1, &ixp_clock.regs->trgt_lo);
 316         __raw_writel(0, &ixp_clock.regs->trgt_hi);
 317         __raw_writel(TTIPEND, &ixp_clock.regs->event);
 318
 319         if (MASTER_IRQ != setup_interrupt(MASTER_GPIO)) {
 320                 pr_err("failed to setup gpio %d as irq\n", MASTER_GPIO);
 321                 goto no_master;
 322         }
 323         if (SLAVE_IRQ != setup_interrupt(SLAVE_GPIO)) {
 324                 pr_err("failed to setup gpio %d as irq\n", SLAVE_GPIO);
 325                 goto no_slave;
 326         }
 327
 328         return 0;
 329 no_slave:
 330         free_irq(MASTER_IRQ, &ixp_clock);
 331 no_master:
 332         ptp_clock_unregister(ixp_clock.ptp_clock);
 333         return -ENODEV;
 334 }
 335
 336 module_init(ptp_ixp_init);
 337 module_exit(ptp_ixp_exit);
 338
 339 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
 340 MODULE_DESCRIPTION("PTP clock using the IXP46X timer");
 341 MODULE_LICENSE("GPL");