root/drivers/net/ethernet/mellanox/mlx4/en_clock.c

DEFINITIONS

1. mlx4_en_read_clock
2. mlx4_en_get_cqe_ts
3. mlx4_en_fill_hwtstamps
4. mlx4_en_remove_timestamp
5. mlx4_en_ptp_overflow_check
6. mlx4_en_phc_adjfreq
7. mlx4_en_phc_adjtime
8. mlx4_en_phc_gettime
9. mlx4_en_phc_settime
10. mlx4_en_phc_enable
11. freq_to_shift
12. mlx4_en_init_timestamp

   1 /*
   2  * Copyright (c) 2012 Mellanox Technologies. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  */
  33 
  34 #include <linux/mlx4/device.h>
  35 #include <linux/clocksource.h>
  36 
  37 #include "mlx4_en.h"
  38 
  39 /* mlx4_en_read_clock - read raw cycle counter (to be used by time counter)
  40  */
  41 static u64 mlx4_en_read_clock(const struct cyclecounter *tc)
  42 {
  43         struct mlx4_en_dev *mdev =
  44                 container_of(tc, struct mlx4_en_dev, cycles);
  45         struct mlx4_dev *dev = mdev->dev;
  46 
  47         return mlx4_read_clock(dev) & tc->mask;
  48 }
  49 
  50 u64 mlx4_en_get_cqe_ts(struct mlx4_cqe *cqe)
  51 {
  52         u64 hi, lo;
  53         struct mlx4_ts_cqe *ts_cqe = (struct mlx4_ts_cqe *)cqe;
  54 
  55         lo = (u64)be16_to_cpu(ts_cqe->timestamp_lo);
  56         hi = ((u64)be32_to_cpu(ts_cqe->timestamp_hi) + !lo) << 16;
  57 
  58         return hi | lo;
  59 }
  60 
  61 void mlx4_en_fill_hwtstamps(struct mlx4_en_dev *mdev,
  62                             struct skb_shared_hwtstamps *hwts,
  63                             u64 timestamp)
  64 {
  65         unsigned int seq;
  66         u64 nsec;
  67 
  68         do {
  69                 seq = read_seqbegin(&mdev->clock_lock);
  70                 nsec = timecounter_cyc2time(&mdev->clock, timestamp);
  71         } while (read_seqretry(&mdev->clock_lock, seq));
  72 
  73         memset(hwts, 0, sizeof(struct skb_shared_hwtstamps));
  74         hwts->hwtstamp = ns_to_ktime(nsec);
  75 }
  76 
  77 /**
  78  * mlx4_en_remove_timestamp - disable PTP device
  79  * @mdev: board private structure
  80  *
  81  * Stop the PTP support.
  82  **/
  83 void mlx4_en_remove_timestamp(struct mlx4_en_dev *mdev)
  84 {
  85         if (mdev->ptp_clock) {
  86                 ptp_clock_unregister(mdev->ptp_clock);
  87                 mdev->ptp_clock = NULL;
  88                 mlx4_info(mdev, "removed PHC\n");
  89         }
  90 }
  91 
  92 #define MLX4_EN_WRAP_AROUND_SEC 10UL
  93 /* By scheduling the overflow check every 5 seconds, we have a reasonably
  94  * good chance we wont miss a wrap around.
  95  * TOTO: Use a timer instead of a work queue to increase the guarantee.
  96  */
  97 #define MLX4_EN_OVERFLOW_PERIOD (MLX4_EN_WRAP_AROUND_SEC * HZ / 2)
  98 
  99 void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev)
 100 {
 101         bool timeout = time_is_before_jiffies(mdev->last_overflow_check +
 102                                               MLX4_EN_OVERFLOW_PERIOD);
 103         unsigned long flags;
 104 
 105         if (timeout) {
 106                 write_seqlock_irqsave(&mdev->clock_lock, flags);
 107                 timecounter_read(&mdev->clock);
 108                 write_sequnlock_irqrestore(&mdev->clock_lock, flags);
 109                 mdev->last_overflow_check = jiffies;
 110         }
 111 }
 112 
 113 /**
 114  * mlx4_en_phc_adjfreq - adjust the frequency of the hardware clock
 115  * @ptp: ptp clock structure
 116  * @delta: Desired frequency change in parts per billion
 117  *
 118  * Adjust the frequency of the PHC cycle counter by the indicated delta from
 119  * the base frequency.
 120  **/
 121 static int mlx4_en_phc_adjfreq(struct ptp_clock_info *ptp, s32 delta)
 122 {
 123         u64 adj;
 124         u32 diff, mult;
 125         int neg_adj = 0;
 126         unsigned long flags;
 127         struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
 128                                                 ptp_clock_info);
 129 
 130         if (delta < 0) {
 131                 neg_adj = 1;
 132                 delta = -delta;
 133         }
 134         mult = mdev->nominal_c_mult;
 135         adj = mult;
 136         adj *= delta;
 137         diff = div_u64(adj, 1000000000ULL);
 138 
 139         write_seqlock_irqsave(&mdev->clock_lock, flags);
 140         timecounter_read(&mdev->clock);
 141         mdev->cycles.mult = neg_adj ? mult - diff : mult + diff;
 142         write_sequnlock_irqrestore(&mdev->clock_lock, flags);
 143 
 144         return 0;
 145 }
 146 
 147 /**
 148  * mlx4_en_phc_adjtime - Shift the time of the hardware clock
 149  * @ptp: ptp clock structure
 150  * @delta: Desired change in nanoseconds
 151  *
 152  * Adjust the timer by resetting the timecounter structure.
 153  **/
 154 static int mlx4_en_phc_adjtime(struct ptp_clock_info *ptp, s64 delta)
 155 {
 156         struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
 157                                                 ptp_clock_info);
 158         unsigned long flags;
 159 
 160         write_seqlock_irqsave(&mdev->clock_lock, flags);
 161         timecounter_adjtime(&mdev->clock, delta);
 162         write_sequnlock_irqrestore(&mdev->clock_lock, flags);
 163 
 164         return 0;
 165 }
 166 
 167 /**
 168  * mlx4_en_phc_gettime - Reads the current time from the hardware clock
 169  * @ptp: ptp clock structure
 170  * @ts: timespec structure to hold the current time value
 171  *
 172  * Read the timecounter and return the correct value in ns after converting
 173  * it into a struct timespec.
 174  **/
 175 static int mlx4_en_phc_gettime(struct ptp_clock_info *ptp,
 176                                struct timespec64 *ts)
 177 {
 178         struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
 179                                                 ptp_clock_info);
 180         unsigned long flags;
 181         u64 ns;
 182 
 183         write_seqlock_irqsave(&mdev->clock_lock, flags);
 184         ns = timecounter_read(&mdev->clock);
 185         write_sequnlock_irqrestore(&mdev->clock_lock, flags);
 186 
 187         *ts = ns_to_timespec64(ns);
 188 
 189         return 0;
 190 }
 191 
 192 /**
 193  * mlx4_en_phc_settime - Set the current time on the hardware clock
 194  * @ptp: ptp clock structure
 195  * @ts: timespec containing the new time for the cycle counter
 196  *
 197  * Reset the timecounter to use a new base value instead of the kernel
 198  * wall timer value.
 199  **/
 200 static int mlx4_en_phc_settime(struct ptp_clock_info *ptp,
 201                                const struct timespec64 *ts)
 202 {
 203         struct mlx4_en_dev *mdev = container_of(ptp, struct mlx4_en_dev,
 204                                                 ptp_clock_info);
 205         u64 ns = timespec64_to_ns(ts);
 206         unsigned long flags;
 207 
 208         /* reset the timecounter */
 209         write_seqlock_irqsave(&mdev->clock_lock, flags);
 210         timecounter_init(&mdev->clock, &mdev->cycles, ns);
 211         write_sequnlock_irqrestore(&mdev->clock_lock, flags);
 212 
 213         return 0;
 214 }
 215 
 216 /**
 217  * mlx4_en_phc_enable - enable or disable an ancillary feature
 218  * @ptp: ptp clock structure
 219  * @request: Desired resource to enable or disable
 220  * @on: Caller passes one to enable or zero to disable
 221  *
 222  * Enable (or disable) ancillary features of the PHC subsystem.
 223  * Currently, no ancillary features are supported.
 224  **/
 225 static int mlx4_en_phc_enable(struct ptp_clock_info __always_unused *ptp,
 226                               struct ptp_clock_request __always_unused *request,
 227                               int __always_unused on)
 228 {
 229         return -EOPNOTSUPP;
 230 }
 231 
 232 static const struct ptp_clock_info mlx4_en_ptp_clock_info = {
 233         .owner          = THIS_MODULE,
 234         .max_adj        = 100000000,
 235         .n_alarm        = 0,
 236         .n_ext_ts       = 0,
 237         .n_per_out      = 0,
 238         .n_pins         = 0,
 239         .pps            = 0,
 240         .adjfreq        = mlx4_en_phc_adjfreq,
 241         .adjtime        = mlx4_en_phc_adjtime,
 242         .gettime64      = mlx4_en_phc_gettime,
 243         .settime64      = mlx4_en_phc_settime,
 244         .enable         = mlx4_en_phc_enable,
 245 };
 246 
 247 
 248 /* This function calculates the max shift that enables the user range
 249  * of MLX4_EN_WRAP_AROUND_SEC values in the cycles register.
 250  */
 251 static u32 freq_to_shift(u16 freq)
 252 {
 253         u32 freq_khz = freq * 1000;
 254         u64 max_val_cycles = freq_khz * 1000 * MLX4_EN_WRAP_AROUND_SEC;
 255         u64 max_val_cycles_rounded = 1ULL << fls64(max_val_cycles - 1);
 256         /* calculate max possible multiplier in order to fit in 64bit */
 257         u64 max_mul = div64_u64(ULLONG_MAX, max_val_cycles_rounded);
 258 
 259         /* This comes from the reverse of clocksource_khz2mult */
 260         return ilog2(div_u64(max_mul * freq_khz, 1000000));
 261 }
 262 
 263 void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
 264 {
 265         struct mlx4_dev *dev = mdev->dev;
 266         unsigned long flags;
 267 
 268         /* mlx4_en_init_timestamp is called for each netdev.
 269          * mdev->ptp_clock is common for all ports, skip initialization if
 270          * was done for other port.
 271          */
 272         if (mdev->ptp_clock)
 273                 return;
 274 
 275         seqlock_init(&mdev->clock_lock);
 276 
 277         memset(&mdev->cycles, 0, sizeof(mdev->cycles));
 278         mdev->cycles.read = mlx4_en_read_clock;
 279         mdev->cycles.mask = CLOCKSOURCE_MASK(48);
 280         mdev->cycles.shift = freq_to_shift(dev->caps.hca_core_clock);
 281         mdev->cycles.mult =
 282                 clocksource_khz2mult(1000 * dev->caps.hca_core_clock, mdev->cycles.shift);
 283         mdev->nominal_c_mult = mdev->cycles.mult;
 284 
 285         write_seqlock_irqsave(&mdev->clock_lock, flags);
 286         timecounter_init(&mdev->clock, &mdev->cycles,
 287                          ktime_to_ns(ktime_get_real()));
 288         write_sequnlock_irqrestore(&mdev->clock_lock, flags);
 289 
 290         /* Configure the PHC */
 291         mdev->ptp_clock_info = mlx4_en_ptp_clock_info;
 292         snprintf(mdev->ptp_clock_info.name, 16, "mlx4 ptp");
 293 
 294         mdev->ptp_clock = ptp_clock_register(&mdev->ptp_clock_info,
 295                                              &mdev->pdev->dev);
 296         if (IS_ERR(mdev->ptp_clock)) {
 297                 mdev->ptp_clock = NULL;
 298                 mlx4_err(mdev, "ptp_clock_register failed\n");
 299         } else if (mdev->ptp_clock) {
 300                 mlx4_info(mdev, "registered PHC clock\n");
 301         }
 302 
 303 }