drivers/ptp/ptp_dte.c

   1 /*
   2  * Copyright 2017 Broadcom
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation version 2.
   7  *
   8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9  * kind, whether express or implied; without even the implied warranty
  10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/err.h>
  15 #include <linux/io.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/ptp_clock_kernel.h>
  19 #include <linux/types.h>
  20
  21 #define DTE_NCO_LOW_TIME_REG    0x00
  22 #define DTE_NCO_TIME_REG        0x04
  23 #define DTE_NCO_OVERFLOW_REG    0x08
  24 #define DTE_NCO_INC_REG         0x0c
  25
  26 #define DTE_NCO_SUM2_MASK       0xffffffff
  27 #define DTE_NCO_SUM2_SHIFT      4ULL
  28
  29 #define DTE_NCO_SUM3_MASK       0xff
  30 #define DTE_NCO_SUM3_SHIFT      36ULL
  31 #define DTE_NCO_SUM3_WR_SHIFT   8
  32
  33 #define DTE_NCO_TS_WRAP_MASK    0xfff
  34 #define DTE_NCO_TS_WRAP_LSHIFT  32
  35
  36 #define DTE_NCO_INC_DEFAULT     0x80000000
  37 #define DTE_NUM_REGS_TO_RESTORE 4
  38
  39 /* Full wrap around is 44bits in ns (~4.887 hrs) */
  40 #define DTE_WRAP_AROUND_NSEC_SHIFT 44
  41
  42 /* 44 bits NCO */
  43 #define DTE_NCO_MAX_NS  0xFFFFFFFFFFFLL
  44
  45 /* 125MHz with 3.29 reg cfg */
  46 #define DTE_PPB_ADJ(ppb) (u32)(div64_u64((((u64)abs(ppb) * BIT(28)) +\
  47                                       62500000ULL), 125000000ULL))
  48
  49 /* ptp dte priv structure */
  50 struct ptp_dte {
  51         void __iomem *regs;
  52         struct ptp_clock *ptp_clk;
  53         struct ptp_clock_info caps;
  54         struct device *dev;
  55         u32 ts_ovf_last;
  56         u32 ts_wrap_cnt;
  57         spinlock_t lock;
  58         u32 reg_val[DTE_NUM_REGS_TO_RESTORE];
  59 };
  60
  61 static void dte_write_nco(void __iomem *regs, s64 ns)
  62 {
  63         u32 sum2, sum3;
  64
  65         sum2 = (u32)((ns >> DTE_NCO_SUM2_SHIFT) & DTE_NCO_SUM2_MASK);
  66         /* compensate for ignoring sum1 */
  67         if (sum2 != DTE_NCO_SUM2_MASK)
  68                 sum2++;
  69
  70         /* to write sum3, bits [15:8] needs to be written */
  71         sum3 = (u32)(((ns >> DTE_NCO_SUM3_SHIFT) & DTE_NCO_SUM3_MASK) <<
  72                      DTE_NCO_SUM3_WR_SHIFT);
  73
  74         writel(0, (regs + DTE_NCO_LOW_TIME_REG));
  75         writel(sum2, (regs + DTE_NCO_TIME_REG));
  76         writel(sum3, (regs + DTE_NCO_OVERFLOW_REG));
  77 }
  78
  79 static s64 dte_read_nco(void __iomem *regs)
  80 {
  81         u32 sum2, sum3;
  82         s64 ns;
  83
  84         /*
  85          * ignoring sum1 (4 bits) gives a 16ns resolution, which
  86          * works due to the async register read.
  87          */
  88         sum3 = readl(regs + DTE_NCO_OVERFLOW_REG) & DTE_NCO_SUM3_MASK;
  89         sum2 = readl(regs + DTE_NCO_TIME_REG);
  90         ns = ((s64)sum3 << DTE_NCO_SUM3_SHIFT) |
  91                  ((s64)sum2 << DTE_NCO_SUM2_SHIFT);
  92
  93         return ns;
  94 }
  95
  96 static void dte_write_nco_delta(struct ptp_dte *ptp_dte, s64 delta)
  97 {
  98         s64 ns;
  99
 100         ns = dte_read_nco(ptp_dte->regs);
 101
 102         /* handle wraparound conditions */
 103         if ((delta < 0) && (abs(delta) > ns)) {
 104                 if (ptp_dte->ts_wrap_cnt) {
 105                         ns += DTE_NCO_MAX_NS + delta;
 106                         ptp_dte->ts_wrap_cnt--;
 107                 } else {
 108                         ns = 0;
 109                 }
 110         } else {
 111                 ns += delta;
 112                 if (ns > DTE_NCO_MAX_NS) {
 113                         ptp_dte->ts_wrap_cnt++;
 114                         ns -= DTE_NCO_MAX_NS;
 115                 }
 116         }
 117
 118         dte_write_nco(ptp_dte->regs, ns);
 119
 120         ptp_dte->ts_ovf_last = (ns >> DTE_NCO_TS_WRAP_LSHIFT) &
 121                         DTE_NCO_TS_WRAP_MASK;
 122 }
 123
 124 static s64 dte_read_nco_with_ovf(struct ptp_dte *ptp_dte)
 125 {
 126         u32 ts_ovf;
 127         s64 ns = 0;
 128
 129         ns = dte_read_nco(ptp_dte->regs);
 130
 131         /*Timestamp overflow: 8 LSB bits of sum3, 4 MSB bits of sum2 */
 132         ts_ovf = (ns >> DTE_NCO_TS_WRAP_LSHIFT) & DTE_NCO_TS_WRAP_MASK;
 133
 134         /* Check for wrap around */
 135         if (ts_ovf < ptp_dte->ts_ovf_last)
 136                 ptp_dte->ts_wrap_cnt++;
 137
 138         ptp_dte->ts_ovf_last = ts_ovf;
 139
 140         /* adjust for wraparounds */
 141         ns += (s64)(BIT_ULL(DTE_WRAP_AROUND_NSEC_SHIFT) * ptp_dte->ts_wrap_cnt);
 142
 143         return ns;
 144 }
 145
 146 static int ptp_dte_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
 147 {
 148         u32 nco_incr;
 149         unsigned long flags;
 150         struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
 151
 152         if (abs(ppb) > ptp_dte->caps.max_adj) {
 153                 dev_err(ptp_dte->dev, "ppb adj too big\n");
 154                 return -EINVAL;
 155         }
 156
 157         if (ppb < 0)
 158                 nco_incr = DTE_NCO_INC_DEFAULT - DTE_PPB_ADJ(ppb);
 159         else
 160                 nco_incr = DTE_NCO_INC_DEFAULT + DTE_PPB_ADJ(ppb);
 161
 162         spin_lock_irqsave(&ptp_dte->lock, flags);
 163         writel(nco_incr, ptp_dte->regs + DTE_NCO_INC_REG);
 164         spin_unlock_irqrestore(&ptp_dte->lock, flags);
 165
 166         return 0;
 167 }
 168
 169 static int ptp_dte_adjtime(struct ptp_clock_info *ptp, s64 delta)
 170 {
 171         unsigned long flags;
 172         struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
 173
 174         spin_lock_irqsave(&ptp_dte->lock, flags);
 175         dte_write_nco_delta(ptp_dte, delta);
 176         spin_unlock_irqrestore(&ptp_dte->lock, flags);
 177
 178         return 0;
 179 }
 180
 181 static int ptp_dte_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 182 {
 183         unsigned long flags;
 184         struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
 185
 186         spin_lock_irqsave(&ptp_dte->lock, flags);
 187         *ts = ns_to_timespec64(dte_read_nco_with_ovf(ptp_dte));
 188         spin_unlock_irqrestore(&ptp_dte->lock, flags);
 189
 190         return 0;
 191 }
 192
 193 static int ptp_dte_settime(struct ptp_clock_info *ptp,
 194                              const struct timespec64 *ts)
 195 {
 196         unsigned long flags;
 197         struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
 198
 199         spin_lock_irqsave(&ptp_dte->lock, flags);
 200
 201         /* Disable nco increment */
 202         writel(0, ptp_dte->regs + DTE_NCO_INC_REG);
 203
 204         dte_write_nco(ptp_dte->regs, timespec64_to_ns(ts));
 205
 206         /* reset overflow and wrap counter */
 207         ptp_dte->ts_ovf_last = 0;
 208         ptp_dte->ts_wrap_cnt = 0;
 209
 210         /* Enable nco increment */
 211         writel(DTE_NCO_INC_DEFAULT, ptp_dte->regs + DTE_NCO_INC_REG);
 212
 213         spin_unlock_irqrestore(&ptp_dte->lock, flags);
 214
 215         return 0;
 216 }
 217
 218 static int ptp_dte_enable(struct ptp_clock_info *ptp,
 219                             struct ptp_clock_request *rq, int on)
 220 {
 221         return -EOPNOTSUPP;
 222 }
 223
 224 static struct ptp_clock_info ptp_dte_caps = {
 225         .owner          = THIS_MODULE,
 226         .name           = "DTE PTP timer",
 227         .max_adj        = 50000000,
 228         .n_ext_ts       = 0,
 229         .n_pins         = 0,
 230         .pps            = 0,
 231         .adjfreq        = ptp_dte_adjfreq,
 232         .adjtime        = ptp_dte_adjtime,
 233         .gettime64      = ptp_dte_gettime,
 234         .settime64      = ptp_dte_settime,
 235         .enable         = ptp_dte_enable,
 236 };
 237
 238 static int ptp_dte_probe(struct platform_device *pdev)
 239 {
 240         struct ptp_dte *ptp_dte;
 241         struct device *dev = &pdev->dev;
 242         struct resource *res;
 243
 244         ptp_dte = devm_kzalloc(dev, sizeof(struct ptp_dte), GFP_KERNEL);
 245         if (!ptp_dte)
 246                 return -ENOMEM;
 247
 248         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 249         ptp_dte->regs = devm_ioremap_resource(dev, res);
 250         if (IS_ERR(ptp_dte->regs)) {
 251                 dev_err(dev,
 252                         "%s: io remap failed\n", __func__);
 253                 return PTR_ERR(ptp_dte->regs);
 254         }
 255
 256         spin_lock_init(&ptp_dte->lock);
 257
 258         ptp_dte->dev = dev;
 259         ptp_dte->caps = ptp_dte_caps;
 260         ptp_dte->ptp_clk = ptp_clock_register(&ptp_dte->caps, &pdev->dev);
 261         if (IS_ERR(ptp_dte->ptp_clk)) {
 262                 dev_err(dev,
 263                         "%s: Failed to register ptp clock\n", __func__);
 264                 return PTR_ERR(ptp_dte->ptp_clk);
 265         }
 266
 267         platform_set_drvdata(pdev, ptp_dte);
 268
 269         dev_info(dev, "ptp clk probe done\n");
 270
 271         return 0;
 272 }
 273
 274 static int ptp_dte_remove(struct platform_device *pdev)
 275 {
 276         struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
 277         u8 i;
 278
 279         ptp_clock_unregister(ptp_dte->ptp_clk);
 280
 281         for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++)
 282                 writel(0, ptp_dte->regs + (i * sizeof(u32)));
 283
 284         return 0;
 285 }
 286
 287 #ifdef CONFIG_PM_SLEEP
 288 static int ptp_dte_suspend(struct device *dev)
 289 {
 290         struct platform_device *pdev = to_platform_device(dev);
 291         struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
 292         u8 i;
 293
 294         for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
 295                 ptp_dte->reg_val[i] =
 296                         readl(ptp_dte->regs + (i * sizeof(u32)));
 297         }
 298
 299         /* disable the nco */
 300         writel(0, ptp_dte->regs + DTE_NCO_INC_REG);
 301
 302         return 0;
 303 }
 304
 305 static int ptp_dte_resume(struct device *dev)
 306 {
 307         struct platform_device *pdev = to_platform_device(dev);
 308         struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
 309         u8 i;
 310
 311         for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
 312                 if ((i * sizeof(u32)) != DTE_NCO_OVERFLOW_REG)
 313                         writel(ptp_dte->reg_val[i],
 314                                 (ptp_dte->regs + (i * sizeof(u32))));
 315                 else
 316                         writel(((ptp_dte->reg_val[i] &
 317                                 DTE_NCO_SUM3_MASK) << DTE_NCO_SUM3_WR_SHIFT),
 318                                 (ptp_dte->regs + (i * sizeof(u32))));
 319         }
 320
 321         return 0;
 322 }
 323
 324 static const struct dev_pm_ops ptp_dte_pm_ops = {
 325         .suspend = ptp_dte_suspend,
 326         .resume = ptp_dte_resume
 327 };
 328
 329 #define PTP_DTE_PM_OPS  (&ptp_dte_pm_ops)
 330 #else
 331 #define PTP_DTE_PM_OPS  NULL
 332 #endif
 333
 334 static const struct of_device_id ptp_dte_of_match[] = {
 335         { .compatible = "brcm,ptp-dte", },
 336         {},
 337 };
 338 MODULE_DEVICE_TABLE(of, ptp_dte_of_match);
 339
 340 static struct platform_driver ptp_dte_driver = {
 341         .driver = {
 342                 .name = "ptp-dte",
 343                 .pm = PTP_DTE_PM_OPS,
 344                 .of_match_table = ptp_dte_of_match,
 345         },
 346         .probe    = ptp_dte_probe,
 347         .remove   = ptp_dte_remove,
 348 };
 349 module_platform_driver(ptp_dte_driver);
 350
 351 MODULE_AUTHOR("Broadcom");
 352 MODULE_DESCRIPTION("Broadcom DTE PTP Clock driver");
 353 MODULE_LICENSE("GPL v2");