git.librecmc.org Git - librecmc/librecmc.git/blob

   1 From 546bac0479e51024027f8c8820f912573643b101 Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Wed, 18 Jan 2017 07:31:57 +1100
   4 Subject: [PATCH] clk: bcm2835: Add leaf clock measurement support, disabled by
   5  default
   6
   7 This proved incredibly useful during debugging of the DSI driver, to
   8 see if our clocks were running at rate we requested.  Let's leave it
   9 here for the next person interacting with clocks on the platform (and
  10 so that hopefully we can just hook it up to debugfs some day).
  11
  12 Signed-off-by: Eric Anholt <eric@anholt.net>
  13 Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
  14 (cherry picked from commit 3f9195811d8d829556c4cd88d3f9e56a80d5ba60)
  15 ---
  16  drivers/clk/bcm/clk-bcm2835.c | 144 ++++++++++++++++++++++++++++++++++--------
  17  1 file changed, 119 insertions(+), 25 deletions(-)
  18
  19 --- a/drivers/clk/bcm/clk-bcm2835.c
  20 +++ b/drivers/clk/bcm/clk-bcm2835.c
  21 @@ -39,6 +39,7 @@
  22  #include <linux/clk.h>
  23  #include <linux/clk/bcm2835.h>
  24  #include <linux/debugfs.h>
  25 +#include <linux/delay.h>
  26  #include <linux/module.h>
  27  #include <linux/of.h>
  28  #include <linux/platform_device.h>
  29 @@ -98,7 +99,8 @@
  30  #define CM_SMIDIV              0x0b4
  31  /* no definition for 0x0b8  and 0x0bc */
  32  #define CM_TCNTCTL             0x0c0
  33 -#define CM_TCNTDIV             0x0c4
  34 +# define CM_TCNT_SRC1_SHIFT            12
  35 +#define CM_TCNTCNT             0x0c4
  36  #define CM_TECCTL              0x0c8
  37  #define CM_TECDIV              0x0cc
  38  #define CM_TD0CTL              0x0d0
  39 @@ -338,6 +340,61 @@ static inline u32 cprman_read(struct bcm
  40         return readl(cprman->regs + reg);
  41  }
  42
  43 +/* Does a cycle of measuring a clock through the TCNT clock, which may
  44 + * source from many other clocks in the system.
  45 + */
  46 +static unsigned long bcm2835_measure_tcnt_mux(struct bcm2835_cprman *cprman,
  47 +                                             u32 tcnt_mux)
  48 +{
  49 +       u32 osccount = 19200; /* 1ms */
  50 +       u32 count;
  51 +       ktime_t timeout;
  52 +
  53 +       spin_lock(&cprman->regs_lock);
  54 +
  55 +       cprman_write(cprman, CM_TCNTCTL, CM_KILL);
  56 +
  57 +       cprman_write(cprman, CM_TCNTCTL,
  58 +                    (tcnt_mux & CM_SRC_MASK) |
  59 +                    (tcnt_mux >> CM_SRC_BITS) << CM_TCNT_SRC1_SHIFT);
  60 +
  61 +       cprman_write(cprman, CM_OSCCOUNT, osccount);
  62 +
  63 +       /* do a kind delay at the start */
  64 +       mdelay(1);
  65 +
  66 +       /* Finish off whatever is left of OSCCOUNT */
  67 +       timeout = ktime_add_ns(ktime_get(), LOCK_TIMEOUT_NS);
  68 +       while (cprman_read(cprman, CM_OSCCOUNT)) {
  69 +               if (ktime_after(ktime_get(), timeout)) {
  70 +                       dev_err(cprman->dev, "timeout waiting for OSCCOUNT\n");
  71 +                       count = 0;
  72 +                       goto out;
  73 +               }
  74 +               cpu_relax();
  75 +       }
  76 +
  77 +       /* Wait for BUSY to clear. */
  78 +       timeout = ktime_add_ns(ktime_get(), LOCK_TIMEOUT_NS);
  79 +       while (cprman_read(cprman, CM_TCNTCTL) & CM_BUSY) {
  80 +               if (ktime_after(ktime_get(), timeout)) {
  81 +                       dev_err(cprman->dev, "timeout waiting for !BUSY\n");
  82 +                       count = 0;
  83 +                       goto out;
  84 +               }
  85 +               cpu_relax();
  86 +       }
  87 +
  88 +       count = cprman_read(cprman, CM_TCNTCNT);
  89 +
  90 +       cprman_write(cprman, CM_TCNTCTL, 0);
  91 +
  92 +out:
  93 +       spin_unlock(&cprman->regs_lock);
  94 +
  95 +       return count * 1000;
  96 +}
  97 +
  98  static int bcm2835_debugfs_regset(struct bcm2835_cprman *cprman, u32 base,
  99                                   struct debugfs_reg32 *regs, size_t nregs,
 100                                   struct dentry *dentry)
 101 @@ -473,6 +530,8 @@ struct bcm2835_clock_data {
 102
 103         bool is_vpu_clock;
 104         bool is_mash_clock;
 105 +
 106 +       u32 tcnt_mux;
 107  };
 108
 109  struct bcm2835_gate_data {
 110 @@ -1008,6 +1067,17 @@ static int bcm2835_clock_on(struct clk_h
 111                      CM_GATE);
 112         spin_unlock(&cprman->regs_lock);
 113
 114 +       /* Debug code to measure the clock once it's turned on to see
 115 +        * if it's ticking at the rate we expect.
 116 +        */
 117 +       if (data->tcnt_mux && false) {
 118 +               dev_info(cprman->dev,
 119 +                        "clk %s: rate %ld, measure %ld\n",
 120 +                        data->name,
 121 +                        clk_hw_get_rate(hw),
 122 +                        bcm2835_measure_tcnt_mux(cprman, data->tcnt_mux));
 123 +       }
 124 +
 125         return 0;
 126  }
 127
 128 @@ -1774,7 +1844,8 @@ static const struct bcm2835_clk_desc clk
 129                 .ctl_reg = CM_OTPCTL,
 130                 .div_reg = CM_OTPDIV,
 131                 .int_bits = 4,
 132 -               .frac_bits = 0),
 133 +               .frac_bits = 0,
 134 +               .tcnt_mux = 6),
 135         /*
 136          * Used for a 1Mhz clock for the system clocksource, and also used
 137          * bythe watchdog timer and the camera pulse generator.
 138 @@ -1808,13 +1879,15 @@ static const struct bcm2835_clk_desc clk
 139                 .ctl_reg = CM_H264CTL,
 140                 .div_reg = CM_H264DIV,
 141                 .int_bits = 4,
 142 -               .frac_bits = 8),
 143 +               .frac_bits = 8,
 144 +               .tcnt_mux = 1),
 145         [BCM2835_CLOCK_ISP]     = REGISTER_VPU_CLK(
 146                 .name = "isp",
 147                 .ctl_reg = CM_ISPCTL,
 148                 .div_reg = CM_ISPDIV,
 149                 .int_bits = 4,
 150 -               .frac_bits = 8),
 151 +               .frac_bits = 8,
 152 +               .tcnt_mux = 2),
 153
 154         /*
 155          * Secondary SDRAM clock.  Used for low-voltage modes when the PLL
 156 @@ -1825,13 +1898,15 @@ static const struct bcm2835_clk_desc clk
 157                 .ctl_reg = CM_SDCCTL,
 158                 .div_reg = CM_SDCDIV,
 159                 .int_bits = 6,
 160 -               .frac_bits = 0),
 161 +               .frac_bits = 0,
 162 +               .tcnt_mux = 3),
 163         [BCM2835_CLOCK_V3D]     = REGISTER_VPU_CLK(
 164                 .name = "v3d",
 165                 .ctl_reg = CM_V3DCTL,
 166                 .div_reg = CM_V3DDIV,
 167                 .int_bits = 4,
 168 -               .frac_bits = 8),
 169 +               .frac_bits = 8,
 170 +               .tcnt_mux = 4),
 171         /*
 172          * VPU clock.  This doesn't have an enable bit, since it drives
 173          * the bus for everything else, and is special so it doesn't need
 174 @@ -1845,7 +1920,8 @@ static const struct bcm2835_clk_desc clk
 175                 .int_bits = 12,
 176                 .frac_bits = 8,
 177                 .flags = CLK_IS_CRITICAL,
 178 -               .is_vpu_clock = true),
 179 +               .is_vpu_clock = true,
 180 +               .tcnt_mux = 5),
 181
 182         /* clocks with per parent mux */
 183         [BCM2835_CLOCK_AVEO]    = REGISTER_PER_CLK(
 184 @@ -1853,19 +1929,22 @@ static const struct bcm2835_clk_desc clk
 185                 .ctl_reg = CM_AVEOCTL,
 186                 .div_reg = CM_AVEODIV,
 187                 .int_bits = 4,
 188 -               .frac_bits = 0),
 189 +               .frac_bits = 0,
 190 +               .tcnt_mux = 38),
 191         [BCM2835_CLOCK_CAM0]    = REGISTER_PER_CLK(
 192                 .name = "cam0",
 193                 .ctl_reg = CM_CAM0CTL,
 194                 .div_reg = CM_CAM0DIV,
 195                 .int_bits = 4,
 196 -               .frac_bits = 8),
 197 +               .frac_bits = 8,
 198 +               .tcnt_mux = 14),
 199         [BCM2835_CLOCK_CAM1]    = REGISTER_PER_CLK(
 200                 .name = "cam1",
 201                 .ctl_reg = CM_CAM1CTL,
 202                 .div_reg = CM_CAM1DIV,
 203                 .int_bits = 4,
 204 -               .frac_bits = 8),
 205 +               .frac_bits = 8,
 206 +               .tcnt_mux = 15),
 207         [BCM2835_CLOCK_DFT]     = REGISTER_PER_CLK(
 208                 .name = "dft",
 209                 .ctl_reg = CM_DFTCTL,
 210 @@ -1877,7 +1956,8 @@ static const struct bcm2835_clk_desc clk
 211                 .ctl_reg = CM_DPICTL,
 212                 .div_reg = CM_DPIDIV,
 213                 .int_bits = 4,
 214 -               .frac_bits = 8),
 215 +               .frac_bits = 8,
 216 +               .tcnt_mux = 17),
 217
 218         /* Arasan EMMC clock */
 219         [BCM2835_CLOCK_EMMC]    = REGISTER_PER_CLK(
 220 @@ -1885,7 +1965,8 @@ static const struct bcm2835_clk_desc clk
 221                 .ctl_reg = CM_EMMCCTL,
 222                 .div_reg = CM_EMMCDIV,
 223                 .int_bits = 4,
 224 -               .frac_bits = 8),
 225 +               .frac_bits = 8,
 226 +               .tcnt_mux = 39),
 227
 228         /* General purpose (GPIO) clocks */
 229         [BCM2835_CLOCK_GP0]     = REGISTER_PER_CLK(
 230 @@ -1894,7 +1975,8 @@ static const struct bcm2835_clk_desc clk
 231                 .div_reg = CM_GP0DIV,
 232                 .int_bits = 12,
 233                 .frac_bits = 12,
 234 -               .is_mash_clock = true),
 235 +               .is_mash_clock = true,
 236 +               .tcnt_mux = 20),
 237         [BCM2835_CLOCK_GP1]     = REGISTER_PER_CLK(
 238                 .name = "gp1",
 239                 .ctl_reg = CM_GP1CTL,
 240 @@ -1902,7 +1984,8 @@ static const struct bcm2835_clk_desc clk
 241                 .int_bits = 12,
 242                 .frac_bits = 12,
 243                 .flags = CLK_IS_CRITICAL,
 244 -               .is_mash_clock = true),
 245 +               .is_mash_clock = true,
 246 +               .tcnt_mux = 21),
 247         [BCM2835_CLOCK_GP2]     = REGISTER_PER_CLK(
 248                 .name = "gp2",
 249                 .ctl_reg = CM_GP2CTL,
 250 @@ -1917,40 +2000,46 @@ static const struct bcm2835_clk_desc clk
 251                 .ctl_reg = CM_HSMCTL,
 252                 .div_reg = CM_HSMDIV,
 253                 .int_bits = 4,
 254 -               .frac_bits = 8),
 255 +               .frac_bits = 8,
 256 +               .tcnt_mux = 22),
 257         [BCM2835_CLOCK_PCM]     = REGISTER_PER_CLK(
 258                 .name = "pcm",
 259                 .ctl_reg = CM_PCMCTL,
 260                 .div_reg = CM_PCMDIV,
 261                 .int_bits = 12,
 262                 .frac_bits = 12,
 263 -               .is_mash_clock = true),
 264 +               .is_mash_clock = true,
 265 +               .tcnt_mux = 23),
 266         [BCM2835_CLOCK_PWM]     = REGISTER_PER_CLK(
 267                 .name = "pwm",
 268                 .ctl_reg = CM_PWMCTL,
 269                 .div_reg = CM_PWMDIV,
 270                 .int_bits = 12,
 271                 .frac_bits = 12,
 272 -               .is_mash_clock = true),
 273 +               .is_mash_clock = true,
 274 +               .tcnt_mux = 24),
 275         [BCM2835_CLOCK_SLIM]    = REGISTER_PER_CLK(
 276                 .name = "slim",
 277                 .ctl_reg = CM_SLIMCTL,
 278                 .div_reg = CM_SLIMDIV,
 279                 .int_bits = 12,
 280                 .frac_bits = 12,
 281 -               .is_mash_clock = true),
 282 +               .is_mash_clock = true,
 283 +               .tcnt_mux = 25),
 284         [BCM2835_CLOCK_SMI]     = REGISTER_PER_CLK(
 285                 .name = "smi",
 286                 .ctl_reg = CM_SMICTL,
 287                 .div_reg = CM_SMIDIV,
 288                 .int_bits = 4,
 289 -               .frac_bits = 8),
 290 +               .frac_bits = 8,
 291 +               .tcnt_mux = 27),
 292         [BCM2835_CLOCK_UART]    = REGISTER_PER_CLK(
 293                 .name = "uart",
 294                 .ctl_reg = CM_UARTCTL,
 295                 .div_reg = CM_UARTDIV,
 296                 .int_bits = 10,
 297 -               .frac_bits = 12),
 298 +               .frac_bits = 12,
 299 +               .tcnt_mux = 28),
 300
 301         /* TV encoder clock.  Only operating frequency is 108Mhz.  */
 302         [BCM2835_CLOCK_VEC]     = REGISTER_PER_CLK(
 303 @@ -1963,7 +2052,8 @@ static const struct bcm2835_clk_desc clk
 304                  * Allow rate change propagation only on PLLH_AUX which is
 305                  * assigned index 7 in the parent array.
 306                  */
 307 -               .set_rate_parent = BIT(7)),
 308 +               .set_rate_parent = BIT(7),
 309 +               .tcnt_mux = 29),
 310
 311         /* dsi clocks */
 312         [BCM2835_CLOCK_DSI0E]   = REGISTER_PER_CLK(
 313 @@ -1971,25 +2061,29 @@ static const struct bcm2835_clk_desc clk
 314                 .ctl_reg = CM_DSI0ECTL,
 315                 .div_reg = CM_DSI0EDIV,
 316                 .int_bits = 4,
 317 -               .frac_bits = 8),
 318 +               .frac_bits = 8,
 319 +               .tcnt_mux = 18),
 320         [BCM2835_CLOCK_DSI1E]   = REGISTER_PER_CLK(
 321                 .name = "dsi1e",
 322                 .ctl_reg = CM_DSI1ECTL,
 323                 .div_reg = CM_DSI1EDIV,
 324                 .int_bits = 4,
 325 -               .frac_bits = 8),
 326 +               .frac_bits = 8,
 327 +               .tcnt_mux = 19),
 328         [BCM2835_CLOCK_DSI0P]   = REGISTER_DSI0_CLK(
 329                 .name = "dsi0p",
 330                 .ctl_reg = CM_DSI0PCTL,
 331                 .div_reg = CM_DSI0PDIV,
 332                 .int_bits = 0,
 333 -               .frac_bits = 0),
 334 +               .frac_bits = 0,
 335 +               .tcnt_mux = 12),
 336         [BCM2835_CLOCK_DSI1P]   = REGISTER_DSI1_CLK(
 337                 .name = "dsi1p",
 338                 .ctl_reg = CM_DSI1PCTL,
 339                 .div_reg = CM_DSI1PDIV,
 340                 .int_bits = 0,
 341 -               .frac_bits = 0),
 342 +               .frac_bits = 0,
 343 +               .tcnt_mux = 13),
 344
 345         /* the gates */
 346