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