drivers/ptp/ptp_dte.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 // Copyright 2017 Broadcom
   3
   4 #include <linux/err.h>
   5 #include <linux/io.h>
   6 #include <linux/module.h>
   7 #include <linux/mod_devicetable.h>
   8 #include <linux/platform_device.h>
   9 #include <linux/ptp_clock_kernel.h>
  10 #include <linux/types.h>
  11
  12 #define DTE_NCO_LOW_TIME_REG    0x00
  13 #define DTE_NCO_TIME_REG        0x04
  14 #define DTE_NCO_OVERFLOW_REG    0x08
  15 #define DTE_NCO_INC_REG         0x0c
  16
  17 #define DTE_NCO_SUM2_MASK       0xffffffff
  18 #define DTE_NCO_SUM2_SHIFT      4ULL
  19
  20 #define DTE_NCO_SUM3_MASK       0xff
  21 #define DTE_NCO_SUM3_SHIFT      36ULL
  22 #define DTE_NCO_SUM3_WR_SHIFT   8
  23
  24 #define DTE_NCO_TS_WRAP_MASK    0xfff
  25 #define DTE_NCO_TS_WRAP_LSHIFT  32
  26
  27 #define DTE_NCO_INC_DEFAULT     0x80000000
  28 #define DTE_NUM_REGS_TO_RESTORE 4
  29
  30 /* Full wrap around is 44bits in ns (~4.887 hrs) */
  31 #define DTE_WRAP_AROUND_NSEC_SHIFT 44
  32
  33 /* 44 bits NCO */
  34 #define DTE_NCO_MAX_NS  0xFFFFFFFFFFFLL
  35
  36 /* 125MHz with 3.29 reg cfg */
  37 #define DTE_PPB_ADJ(ppb) (u32)(div64_u64((((u64)abs(ppb) * BIT(28)) +\
  38                                       62500000ULL), 125000000ULL))
  39
  40 /* ptp dte priv structure */
  41 struct ptp_dte {
  42         void __iomem *regs;
  43         struct ptp_clock *ptp_clk;
  44         struct ptp_clock_info caps;
  45         struct device *dev;
  46         u32 ts_ovf_last;
  47         u32 ts_wrap_cnt;
  48         spinlock_t lock;
  49         u32 reg_val[DTE_NUM_REGS_TO_RESTORE];
  50 };
  51
  52 static void dte_write_nco(void __iomem *regs, s64 ns)
  53 {
  54         u32 sum2, sum3;
  55
  56         sum2 = (u32)((ns >> DTE_NCO_SUM2_SHIFT) & DTE_NCO_SUM2_MASK);
  57         /* compensate for ignoring sum1 */
  58         if (sum2 != DTE_NCO_SUM2_MASK)
  59                 sum2++;
  60
  61         /* to write sum3, bits [15:8] needs to be written */
  62         sum3 = (u32)(((ns >> DTE_NCO_SUM3_SHIFT) & DTE_NCO_SUM3_MASK) <<
  63                      DTE_NCO_SUM3_WR_SHIFT);
  64
  65         writel(0, (regs + DTE_NCO_LOW_TIME_REG));
  66         writel(sum2, (regs + DTE_NCO_TIME_REG));
  67         writel(sum3, (regs + DTE_NCO_OVERFLOW_REG));
  68 }
  69
  70 static s64 dte_read_nco(void __iomem *regs)
  71 {
  72         u32 sum2, sum3;
  73         s64 ns;
  74
  75         /*
  76          * ignoring sum1 (4 bits) gives a 16ns resolution, which
  77          * works due to the async register read.
  78          */
  79         sum3 = readl(regs + DTE_NCO_OVERFLOW_REG) & DTE_NCO_SUM3_MASK;
  80         sum2 = readl(regs + DTE_NCO_TIME_REG);
  81         ns = ((s64)sum3 << DTE_NCO_SUM3_SHIFT) |
  82                  ((s64)sum2 << DTE_NCO_SUM2_SHIFT);
  83
  84         return ns;
  85 }
  86
  87 static void dte_write_nco_delta(struct ptp_dte *ptp_dte, s64 delta)
  88 {
  89         s64 ns;
  90
  91         ns = dte_read_nco(ptp_dte->regs);
  92
  93         /* handle wraparound conditions */
  94         if ((delta < 0) && (abs(delta) > ns)) {
  95                 if (ptp_dte->ts_wrap_cnt) {
  96                         ns += DTE_NCO_MAX_NS + delta;
  97                         ptp_dte->ts_wrap_cnt--;
  98                 } else {
  99                         ns = 0;
 100                 }
 101         } else {
 102                 ns += delta;
 103                 if (ns > DTE_NCO_MAX_NS) {
 104                         ptp_dte->ts_wrap_cnt++;
 105                         ns -= DTE_NCO_MAX_NS;
 106                 }
 107         }
 108
 109         dte_write_nco(ptp_dte->regs, ns);
 110
 111         ptp_dte->ts_ovf_last = (ns >> DTE_NCO_TS_WRAP_LSHIFT) &
 112                         DTE_NCO_TS_WRAP_MASK;
 113 }
 114
 115 static s64 dte_read_nco_with_ovf(struct ptp_dte *ptp_dte)
 116 {
 117         u32 ts_ovf;
 118         s64 ns = 0;
 119
 120         ns = dte_read_nco(ptp_dte->regs);
 121
 122         /*Timestamp overflow: 8 LSB bits of sum3, 4 MSB bits of sum2 */
 123         ts_ovf = (ns >> DTE_NCO_TS_WRAP_LSHIFT) & DTE_NCO_TS_WRAP_MASK;
 124
 125         /* Check for wrap around */
 126         if (ts_ovf < ptp_dte->ts_ovf_last)
 127                 ptp_dte->ts_wrap_cnt++;
 128
 129         ptp_dte->ts_ovf_last = ts_ovf;
 130
 131         /* adjust for wraparounds */
 132         ns += (s64)(BIT_ULL(DTE_WRAP_AROUND_NSEC_SHIFT) * ptp_dte->ts_wrap_cnt);
 133
 134         return ns;
 135 }
 136
 137 static int ptp_dte_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 138 {
 139         s32 ppb = scaled_ppm_to_ppb(scaled_ppm);
 140         u32 nco_incr;
 141         unsigned long flags;
 142         struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
 143
 144         if (abs(ppb) > ptp_dte->caps.max_adj) {
 145                 dev_err(ptp_dte->dev, "ppb adj too big\n");
 146                 return -EINVAL;
 147         }
 148
 149         if (ppb < 0)
 150                 nco_incr = DTE_NCO_INC_DEFAULT - DTE_PPB_ADJ(ppb);
 151         else
 152                 nco_incr = DTE_NCO_INC_DEFAULT + DTE_PPB_ADJ(ppb);
 153
 154         spin_lock_irqsave(&ptp_dte->lock, flags);
 155         writel(nco_incr, ptp_dte->regs + DTE_NCO_INC_REG);
 156         spin_unlock_irqrestore(&ptp_dte->lock, flags);
 157
 158         return 0;
 159 }
 160
 161 static int ptp_dte_adjtime(struct ptp_clock_info *ptp, s64 delta)
 162 {
 163         unsigned long flags;
 164         struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
 165
 166         spin_lock_irqsave(&ptp_dte->lock, flags);
 167         dte_write_nco_delta(ptp_dte, delta);
 168         spin_unlock_irqrestore(&ptp_dte->lock, flags);
 169
 170         return 0;
 171 }
 172
 173 static int ptp_dte_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 174 {
 175         unsigned long flags;
 176         struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
 177
 178         spin_lock_irqsave(&ptp_dte->lock, flags);
 179         *ts = ns_to_timespec64(dte_read_nco_with_ovf(ptp_dte));
 180         spin_unlock_irqrestore(&ptp_dte->lock, flags);
 181
 182         return 0;
 183 }
 184
 185 static int ptp_dte_settime(struct ptp_clock_info *ptp,
 186                              const struct timespec64 *ts)
 187 {
 188         unsigned long flags;
 189         struct ptp_dte *ptp_dte = container_of(ptp, struct ptp_dte, caps);
 190
 191         spin_lock_irqsave(&ptp_dte->lock, flags);
 192
 193         /* Disable nco increment */
 194         writel(0, ptp_dte->regs + DTE_NCO_INC_REG);
 195
 196         dte_write_nco(ptp_dte->regs, timespec64_to_ns(ts));
 197
 198         /* reset overflow and wrap counter */
 199         ptp_dte->ts_ovf_last = 0;
 200         ptp_dte->ts_wrap_cnt = 0;
 201
 202         /* Enable nco increment */
 203         writel(DTE_NCO_INC_DEFAULT, ptp_dte->regs + DTE_NCO_INC_REG);
 204
 205         spin_unlock_irqrestore(&ptp_dte->lock, flags);
 206
 207         return 0;
 208 }
 209
 210 static int ptp_dte_enable(struct ptp_clock_info *ptp,
 211                             struct ptp_clock_request *rq, int on)
 212 {
 213         return -EOPNOTSUPP;
 214 }
 215
 216 static const struct ptp_clock_info ptp_dte_caps = {
 217         .owner          = THIS_MODULE,
 218         .name           = "DTE PTP timer",
 219         .max_adj        = 50000000,
 220         .n_ext_ts       = 0,
 221         .n_pins         = 0,
 222         .pps            = 0,
 223         .adjfine        = ptp_dte_adjfine,
 224         .adjtime        = ptp_dte_adjtime,
 225         .gettime64      = ptp_dte_gettime,
 226         .settime64      = ptp_dte_settime,
 227         .enable         = ptp_dte_enable,
 228 };
 229
 230 static int ptp_dte_probe(struct platform_device *pdev)
 231 {
 232         struct ptp_dte *ptp_dte;
 233         struct device *dev = &pdev->dev;
 234
 235         ptp_dte = devm_kzalloc(dev, sizeof(struct ptp_dte), GFP_KERNEL);
 236         if (!ptp_dte)
 237                 return -ENOMEM;
 238
 239         ptp_dte->regs = devm_platform_ioremap_resource(pdev, 0);
 240         if (IS_ERR(ptp_dte->regs))
 241                 return PTR_ERR(ptp_dte->regs);
 242
 243         spin_lock_init(&ptp_dte->lock);
 244
 245         ptp_dte->dev = dev;
 246         ptp_dte->caps = ptp_dte_caps;
 247         ptp_dte->ptp_clk = ptp_clock_register(&ptp_dte->caps, &pdev->dev);
 248         if (IS_ERR(ptp_dte->ptp_clk)) {
 249                 dev_err(dev,
 250                         "%s: Failed to register ptp clock\n", __func__);
 251                 return PTR_ERR(ptp_dte->ptp_clk);
 252         }
 253
 254         platform_set_drvdata(pdev, ptp_dte);
 255
 256         dev_info(dev, "ptp clk probe done\n");
 257
 258         return 0;
 259 }
 260
 261 static void ptp_dte_remove(struct platform_device *pdev)
 262 {
 263         struct ptp_dte *ptp_dte = platform_get_drvdata(pdev);
 264         u8 i;
 265
 266         ptp_clock_unregister(ptp_dte->ptp_clk);
 267
 268         for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++)
 269                 writel(0, ptp_dte->regs + (i * sizeof(u32)));
 270 }
 271
 272 #ifdef CONFIG_PM_SLEEP
 273 static int ptp_dte_suspend(struct device *dev)
 274 {
 275         struct ptp_dte *ptp_dte = dev_get_drvdata(dev);
 276         u8 i;
 277
 278         for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
 279                 ptp_dte->reg_val[i] =
 280                         readl(ptp_dte->regs + (i * sizeof(u32)));
 281         }
 282
 283         /* disable the nco */
 284         writel(0, ptp_dte->regs + DTE_NCO_INC_REG);
 285
 286         return 0;
 287 }
 288
 289 static int ptp_dte_resume(struct device *dev)
 290 {
 291         struct ptp_dte *ptp_dte = dev_get_drvdata(dev);
 292         u8 i;
 293
 294         for (i = 0; i < DTE_NUM_REGS_TO_RESTORE; i++) {
 295                 if ((i * sizeof(u32)) != DTE_NCO_OVERFLOW_REG)
 296                         writel(ptp_dte->reg_val[i],
 297                                 (ptp_dte->regs + (i * sizeof(u32))));
 298                 else
 299                         writel(((ptp_dte->reg_val[i] &
 300                                 DTE_NCO_SUM3_MASK) << DTE_NCO_SUM3_WR_SHIFT),
 301                                 (ptp_dte->regs + (i * sizeof(u32))));
 302         }
 303
 304         return 0;
 305 }
 306
 307 static const struct dev_pm_ops ptp_dte_pm_ops = {
 308         .suspend = ptp_dte_suspend,
 309         .resume = ptp_dte_resume
 310 };
 311
 312 #define PTP_DTE_PM_OPS  (&ptp_dte_pm_ops)
 313 #else
 314 #define PTP_DTE_PM_OPS  NULL
 315 #endif
 316
 317 static const struct of_device_id ptp_dte_of_match[] = {
 318         { .compatible = "brcm,ptp-dte", },
 319         {},
 320 };
 321 MODULE_DEVICE_TABLE(of, ptp_dte_of_match);
 322
 323 static struct platform_driver ptp_dte_driver = {
 324         .driver = {
 325                 .name = "ptp-dte",
 326                 .pm = PTP_DTE_PM_OPS,
 327                 .of_match_table = ptp_dte_of_match,
 328         },
 329         .probe    = ptp_dte_probe,
 330         .remove_new = ptp_dte_remove,
 331 };
 332 module_platform_driver(ptp_dte_driver);
 333
 334 MODULE_AUTHOR("Broadcom");
 335 MODULE_DESCRIPTION("Broadcom DTE PTP Clock driver");
 336 MODULE_LICENSE("GPL v2");