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 timespec *ts)
 179 {
 180         u64 ns;
 181         u32 remainder;
 182         unsigned long flags;
 183         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 184         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 185
 186         spin_lock_irqsave(&register_lock, flags);
 187
 188         ns = ixp_systime_read(regs);
 189
 190         spin_unlock_irqrestore(&register_lock, flags);
 191
 192         ts->tv_sec = div_u64_rem(ns, 1000000000, &remainder);
 193         ts->tv_nsec = remainder;
 194         return 0;
 195 }
 196
 197 static int ptp_ixp_settime(struct ptp_clock_info *ptp,
 198                            const struct timespec *ts)
 199 {
 200         u64 ns;
 201         unsigned long flags;
 202         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 203         struct ixp46x_ts_regs *regs = ixp_clock->regs;
 204
 205         ns = ts->tv_sec * 1000000000ULL;
 206         ns += ts->tv_nsec;
 207
 208         spin_lock_irqsave(&register_lock, flags);
 209
 210         ixp_systime_write(regs, ns);
 211
 212         spin_unlock_irqrestore(&register_lock, flags);
 213
 214         return 0;
 215 }
 216
 217 static int ptp_ixp_enable(struct ptp_clock_info *ptp,
 218                           struct ptp_clock_request *rq, int on)
 219 {
 220         struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 221
 222         switch (rq->type) {
 223         case PTP_CLK_REQ_EXTTS:
 224                 switch (rq->extts.index) {
 225                 case 0:
 226                         ixp_clock->exts0_enabled = on ? 1 : 0;
 227                         break;
 228                 case 1:
 229                         ixp_clock->exts1_enabled = on ? 1 : 0;
 230                         break;
 231                 default:
 232                         return -EINVAL;
 233                 }
 234                 return 0;
 235         default:
 236                 break;
 237         }
 238
 239         return -EOPNOTSUPP;
 240 }
 241
 242 static struct ptp_clock_info ptp_ixp_caps = {
 243         .owner          = THIS_MODULE,
 244         .name           = "IXP46X timer",
 245         .max_adj        = 66666655,
 246         .n_ext_ts       = N_EXT_TS,
 247         .pps            = 0,
 248         .adjfreq        = ptp_ixp_adjfreq,
 249         .adjtime        = ptp_ixp_adjtime,
 250         .gettime        = ptp_ixp_gettime,
 251         .settime        = ptp_ixp_settime,
 252         .enable         = ptp_ixp_enable,
 253 };
 254
 255 /* module operations */
 256
 257 static struct ixp_clock ixp_clock;
 258
 259 static int setup_interrupt(int gpio)
 260 {
 261         int irq;
 262
 263         gpio_line_config(gpio, IXP4XX_GPIO_IN);
 264
 265         irq = gpio_to_irq(gpio);
 266
 267         if (NO_IRQ == irq)
 268                 return NO_IRQ;
 269
 270         if (irq_set_irq_type(irq, IRQF_TRIGGER_FALLING)) {
 271                 pr_err("cannot set trigger type for irq %d\n", irq);
 272                 return NO_IRQ;
 273         }
 274
 275         if (request_irq(irq, isr, 0, DRIVER, &ixp_clock)) {
 276                 pr_err("request_irq failed for irq %d\n", irq);
 277                 return NO_IRQ;
 278         }
 279
 280         return irq;
 281 }
 282
 283 static void __exit ptp_ixp_exit(void)
 284 {
 285         free_irq(MASTER_IRQ, &ixp_clock);
 286         free_irq(SLAVE_IRQ, &ixp_clock);
 287         ptp_clock_unregister(ixp_clock.ptp_clock);
 288 }
 289
 290 static int __init ptp_ixp_init(void)
 291 {
 292         if (!cpu_is_ixp46x())
 293                 return -ENODEV;
 294
 295         ixp_clock.regs =
 296                 (struct ixp46x_ts_regs __iomem *) IXP4XX_TIMESYNC_BASE_VIRT;
 297
 298         ixp_clock.caps = ptp_ixp_caps;
 299
 300         ixp_clock.ptp_clock = ptp_clock_register(&ixp_clock.caps);
 301
 302         if (IS_ERR(ixp_clock.ptp_clock))
 303                 return PTR_ERR(ixp_clock.ptp_clock);
 304
 305         __raw_writel(DEFAULT_ADDEND, &ixp_clock.regs->addend);
 306         __raw_writel(1, &ixp_clock.regs->trgt_lo);
 307         __raw_writel(0, &ixp_clock.regs->trgt_hi);
 308         __raw_writel(TTIPEND, &ixp_clock.regs->event);
 309
 310         if (MASTER_IRQ != setup_interrupt(MASTER_GPIO)) {
 311                 pr_err("failed to setup gpio %d as irq\n", MASTER_GPIO);
 312                 goto no_master;
 313         }
 314         if (SLAVE_IRQ != setup_interrupt(SLAVE_GPIO)) {
 315                 pr_err("failed to setup gpio %d as irq\n", SLAVE_GPIO);
 316                 goto no_slave;
 317         }
 318
 319         return 0;
 320 no_slave:
 321         free_irq(MASTER_IRQ, &ixp_clock);
 322 no_master:
 323         ptp_clock_unregister(ixp_clock.ptp_clock);
 324         return -ENODEV;
 325 }
 326
 327 module_init(ptp_ixp_init);
 328 module_exit(ptp_ixp_exit);
 329
 330 MODULE_AUTHOR("Richard Cochran <richard.cochran@omicron.at>");
 331 MODULE_DESCRIPTION("PTP clock using the IXP46X timer");
 332 MODULE_LICENSE("GPL");