drivers/net/ethernet/cavium/common/cavium_ptp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* cavium_ptp.c - PTP 1588 clock on Cavium hardware
   3  * Copyright (c) 2003-2015, 2017 Cavium, Inc.
   4  */
   5
   6 #include <linux/device.h>
   7 #include <linux/module.h>
   8 #include <linux/timecounter.h>
   9 #include <linux/pci.h>
  10
  11 #include "cavium_ptp.h"
  12
  13 #define DRV_NAME        "Cavium PTP Driver"
  14
  15 #define PCI_DEVICE_ID_CAVIUM_PTP        0xA00C
  16 #define PCI_DEVICE_ID_CAVIUM_RST        0xA00E
  17
  18 #define PCI_PTP_BAR_NO  0
  19 #define PCI_RST_BAR_NO  0
  20
  21 #define PTP_CLOCK_CFG           0xF00ULL
  22 #define  PTP_CLOCK_CFG_PTP_EN   BIT(0)
  23 #define PTP_CLOCK_LO            0xF08ULL
  24 #define PTP_CLOCK_HI            0xF10ULL
  25 #define PTP_CLOCK_COMP          0xF18ULL
  26
  27 #define RST_BOOT        0x1600ULL
  28 #define CLOCK_BASE_RATE 50000000ULL
  29
  30 static u64 ptp_cavium_clock_get(void)
  31 {
  32         struct pci_dev *pdev;
  33         void __iomem *base;
  34         u64 ret = CLOCK_BASE_RATE * 16;
  35
  36         pdev = pci_get_device(PCI_VENDOR_ID_CAVIUM,
  37                               PCI_DEVICE_ID_CAVIUM_RST, NULL);
  38         if (!pdev)
  39                 goto error;
  40
  41         base = pci_ioremap_bar(pdev, PCI_RST_BAR_NO);
  42         if (!base)
  43                 goto error_put_pdev;
  44
  45         ret = CLOCK_BASE_RATE * ((readq(base + RST_BOOT) >> 33) & 0x3f);
  46
  47         iounmap(base);
  48
  49 error_put_pdev:
  50         pci_dev_put(pdev);
  51
  52 error:
  53         return ret;
  54 }
  55
  56 struct cavium_ptp *cavium_ptp_get(void)
  57 {
  58         struct cavium_ptp *ptp;
  59         struct pci_dev *pdev;
  60
  61         pdev = pci_get_device(PCI_VENDOR_ID_CAVIUM,
  62                               PCI_DEVICE_ID_CAVIUM_PTP, NULL);
  63         if (!pdev)
  64                 return ERR_PTR(-ENODEV);
  65
  66         ptp = pci_get_drvdata(pdev);
  67         if (!ptp)
  68                 ptp = ERR_PTR(-EPROBE_DEFER);
  69         if (IS_ERR(ptp))
  70                 pci_dev_put(pdev);
  71
  72         return ptp;
  73 }
  74 EXPORT_SYMBOL(cavium_ptp_get);
  75
  76 void cavium_ptp_put(struct cavium_ptp *ptp)
  77 {
  78         if (!ptp)
  79                 return;
  80         pci_dev_put(ptp->pdev);
  81 }
  82 EXPORT_SYMBOL(cavium_ptp_put);
  83
  84 /**
  85  * cavium_ptp_adjfine() - Adjust ptp frequency
  86  * @ptp: PTP clock info
  87  * @scaled_ppm: how much to adjust by, in parts per million, but with a
  88  *              16 bit binary fractional field
  89  */
  90 static int cavium_ptp_adjfine(struct ptp_clock_info *ptp_info, long scaled_ppm)
  91 {
  92         struct cavium_ptp *clock =
  93                 container_of(ptp_info, struct cavium_ptp, ptp_info);
  94         unsigned long flags;
  95         u64 comp;
  96         u64 adj;
  97         bool neg_adj = false;
  98
  99         if (scaled_ppm < 0) {
 100                 neg_adj = true;
 101                 scaled_ppm = -scaled_ppm;
 102         }
 103
 104         /* The hardware adds the clock compensation value to the PTP clock
 105          * on every coprocessor clock cycle. Typical convention is that it
 106          * represent number of nanosecond betwen each cycle. In this
 107          * convention compensation value is in 64 bit fixed-point
 108          * representation where upper 32 bits are number of nanoseconds
 109          * and lower is fractions of nanosecond.
 110          * The scaled_ppm represent the ratio in "parts per bilion" by which the
 111          * compensation value should be corrected.
 112          * To calculate new compenstation value we use 64bit fixed point
 113          * arithmetic on following formula
 114          * comp = tbase + tbase * scaled_ppm / (1M * 2^16)
 115          * where tbase is the basic compensation value calculated initialy
 116          * in cavium_ptp_init() -> tbase = 1/Hz. Then we use endian
 117          * independent structure definition to write data to PTP register.
 118          */
 119         comp = ((u64)1000000000ull << 32) / clock->clock_rate;
 120         adj = comp * scaled_ppm;
 121         adj >>= 16;
 122         adj = div_u64(adj, 1000000ull);
 123         comp = neg_adj ? comp - adj : comp + adj;
 124
 125         spin_lock_irqsave(&clock->spin_lock, flags);
 126         writeq(comp, clock->reg_base + PTP_CLOCK_COMP);
 127         spin_unlock_irqrestore(&clock->spin_lock, flags);
 128
 129         return 0;
 130 }
 131
 132 /**
 133  * cavium_ptp_adjtime() - Adjust ptp time
 134  * @ptp:   PTP clock info
 135  * @delta: how much to adjust by, in nanosecs
 136  */
 137 static int cavium_ptp_adjtime(struct ptp_clock_info *ptp_info, s64 delta)
 138 {
 139         struct cavium_ptp *clock =
 140                 container_of(ptp_info, struct cavium_ptp, ptp_info);
 141         unsigned long flags;
 142
 143         spin_lock_irqsave(&clock->spin_lock, flags);
 144         timecounter_adjtime(&clock->time_counter, delta);
 145         spin_unlock_irqrestore(&clock->spin_lock, flags);
 146
 147         /* Sync, for network driver to get latest value */
 148         smp_mb();
 149
 150         return 0;
 151 }
 152
 153 /**
 154  * cavium_ptp_gettime() - Get hardware clock time with adjustment
 155  * @ptp: PTP clock info
 156  * @ts:  timespec
 157  */
 158 static int cavium_ptp_gettime(struct ptp_clock_info *ptp_info,
 159                               struct timespec64 *ts)
 160 {
 161         struct cavium_ptp *clock =
 162                 container_of(ptp_info, struct cavium_ptp, ptp_info);
 163         unsigned long flags;
 164         u64 nsec;
 165
 166         spin_lock_irqsave(&clock->spin_lock, flags);
 167         nsec = timecounter_read(&clock->time_counter);
 168         spin_unlock_irqrestore(&clock->spin_lock, flags);
 169
 170         *ts = ns_to_timespec64(nsec);
 171
 172         return 0;
 173 }
 174
 175 /**
 176  * cavium_ptp_settime() - Set hardware clock time. Reset adjustment
 177  * @ptp: PTP clock info
 178  * @ts:  timespec
 179  */
 180 static int cavium_ptp_settime(struct ptp_clock_info *ptp_info,
 181                               const struct timespec64 *ts)
 182 {
 183         struct cavium_ptp *clock =
 184                 container_of(ptp_info, struct cavium_ptp, ptp_info);
 185         unsigned long flags;
 186         u64 nsec;
 187
 188         nsec = timespec64_to_ns(ts);
 189
 190         spin_lock_irqsave(&clock->spin_lock, flags);
 191         timecounter_init(&clock->time_counter, &clock->cycle_counter, nsec);
 192         spin_unlock_irqrestore(&clock->spin_lock, flags);
 193
 194         return 0;
 195 }
 196
 197 /**
 198  * cavium_ptp_enable() - Request to enable or disable an ancillary feature.
 199  * @ptp: PTP clock info
 200  * @rq:  request
 201  * @on:  is it on
 202  */
 203 static int cavium_ptp_enable(struct ptp_clock_info *ptp_info,
 204                              struct ptp_clock_request *rq, int on)
 205 {
 206         return -EOPNOTSUPP;
 207 }
 208
 209 static u64 cavium_ptp_cc_read(const struct cyclecounter *cc)
 210 {
 211         struct cavium_ptp *clock =
 212                 container_of(cc, struct cavium_ptp, cycle_counter);
 213
 214         return readq(clock->reg_base + PTP_CLOCK_HI);
 215 }
 216
 217 static int cavium_ptp_probe(struct pci_dev *pdev,
 218                             const struct pci_device_id *ent)
 219 {
 220         struct device *dev = &pdev->dev;
 221         struct cavium_ptp *clock;
 222         struct cyclecounter *cc;
 223         u64 clock_cfg;
 224         u64 clock_comp;
 225         int err;
 226
 227         clock = devm_kzalloc(dev, sizeof(*clock), GFP_KERNEL);
 228         if (!clock) {
 229                 err = -ENOMEM;
 230                 goto error;
 231         }
 232
 233         clock->pdev = pdev;
 234
 235         err = pcim_enable_device(pdev);
 236         if (err)
 237                 goto error_free;
 238
 239         err = pcim_iomap_regions(pdev, 1 << PCI_PTP_BAR_NO, pci_name(pdev));
 240         if (err)
 241                 goto error_free;
 242
 243         clock->reg_base = pcim_iomap_table(pdev)[PCI_PTP_BAR_NO];
 244
 245         spin_lock_init(&clock->spin_lock);
 246
 247         cc = &clock->cycle_counter;
 248         cc->read = cavium_ptp_cc_read;
 249         cc->mask = CYCLECOUNTER_MASK(64);
 250         cc->mult = 1;
 251         cc->shift = 0;
 252
 253         timecounter_init(&clock->time_counter, &clock->cycle_counter,
 254                          ktime_to_ns(ktime_get_real()));
 255
 256         clock->clock_rate = ptp_cavium_clock_get();
 257
 258         clock->ptp_info = (struct ptp_clock_info) {
 259                 .owner          = THIS_MODULE,
 260                 .name           = "ThunderX PTP",
 261                 .max_adj        = 1000000000ull,
 262                 .n_ext_ts       = 0,
 263                 .n_pins         = 0,
 264                 .pps            = 0,
 265                 .adjfine        = cavium_ptp_adjfine,
 266                 .adjtime        = cavium_ptp_adjtime,
 267                 .gettime64      = cavium_ptp_gettime,
 268                 .settime64      = cavium_ptp_settime,
 269                 .enable         = cavium_ptp_enable,
 270         };
 271
 272         clock_cfg = readq(clock->reg_base + PTP_CLOCK_CFG);
 273         clock_cfg |= PTP_CLOCK_CFG_PTP_EN;
 274         writeq(clock_cfg, clock->reg_base + PTP_CLOCK_CFG);
 275
 276         clock_comp = ((u64)1000000000ull << 32) / clock->clock_rate;
 277         writeq(clock_comp, clock->reg_base + PTP_CLOCK_COMP);
 278
 279         clock->ptp_clock = ptp_clock_register(&clock->ptp_info, dev);
 280         if (IS_ERR(clock->ptp_clock)) {
 281                 err = PTR_ERR(clock->ptp_clock);
 282                 goto error_stop;
 283         }
 284
 285         pci_set_drvdata(pdev, clock);
 286         return 0;
 287
 288 error_stop:
 289         clock_cfg = readq(clock->reg_base + PTP_CLOCK_CFG);
 290         clock_cfg &= ~PTP_CLOCK_CFG_PTP_EN;
 291         writeq(clock_cfg, clock->reg_base + PTP_CLOCK_CFG);
 292         pcim_iounmap_regions(pdev, 1 << PCI_PTP_BAR_NO);
 293
 294 error_free:
 295         devm_kfree(dev, clock);
 296
 297 error:
 298         /* For `cavium_ptp_get()` we need to differentiate between the case
 299          * when the core has not tried to probe this device and the case when
 300          * the probe failed.  In the later case we pretend that the
 301          * initialization was successful and keep the error in
 302          * `dev->driver_data`.
 303          */
 304         pci_set_drvdata(pdev, ERR_PTR(err));
 305         return 0;
 306 }
 307
 308 static void cavium_ptp_remove(struct pci_dev *pdev)
 309 {
 310         struct cavium_ptp *clock = pci_get_drvdata(pdev);
 311         u64 clock_cfg;
 312
 313         if (IS_ERR_OR_NULL(clock))
 314                 return;
 315
 316         ptp_clock_unregister(clock->ptp_clock);
 317
 318         clock_cfg = readq(clock->reg_base + PTP_CLOCK_CFG);
 319         clock_cfg &= ~PTP_CLOCK_CFG_PTP_EN;
 320         writeq(clock_cfg, clock->reg_base + PTP_CLOCK_CFG);
 321 }
 322
 323 static const struct pci_device_id cavium_ptp_id_table[] = {
 324         { PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, PCI_DEVICE_ID_CAVIUM_PTP) },
 325         { 0, }
 326 };
 327
 328 static struct pci_driver cavium_ptp_driver = {
 329         .name = DRV_NAME,
 330         .id_table = cavium_ptp_id_table,
 331         .probe = cavium_ptp_probe,
 332         .remove = cavium_ptp_remove,
 333 };
 334
 335 module_pci_driver(cavium_ptp_driver);
 336
 337 MODULE_DESCRIPTION(DRV_NAME);
 338 MODULE_AUTHOR("Cavium Networks <support@cavium.com>");
 339 MODULE_LICENSE("GPL v2");
 340 MODULE_DEVICE_TABLE(pci, cavium_ptp_id_table);