target/linux/brcm2708/patches-4.4/0223-Revert-bcm2835-sdhost-Precalc-divisors-and-overclock.patch

   1 From 28d6ecd622da2efdb7a7c6c07ab8a92c82dded6b Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Mon, 4 Apr 2016 12:35:32 +0100
   4 Subject: [PATCH 223/381] Revert "bcm2835-sdhost: Precalc divisors and
   5  overclocks"
   6
   7 This reverts commit 20260462773366a5734e5268dae0a4c179a21a2d.
   8 ---
   9  drivers/mmc/host/bcm2835-sdhost.c | 152 ++++++++++++++++----------------------
  10  1 file changed, 64 insertions(+), 88 deletions(-)
  11
  12 --- a/drivers/mmc/host/bcm2835-sdhost.c
  13 +++ b/drivers/mmc/host/bcm2835-sdhost.c
  14 @@ -154,15 +154,12 @@ struct bcm2835_host {
  15         u32                     pio_timeout;    /* In jiffies */
  16
  17         int                     clock;          /* Current clock speed */
  18 -       int                     clocks[2];
  19
  20         bool                    slow_card;      /* Force 11-bit divisor */
  21
  22         unsigned int            max_clk;        /* Max src clock freq */
  23 -       unsigned int            src_clks[2];    /* Min/max src clock freqs */
  24 -       unsigned int            cur_clk_idx;    /* Index of current clock */
  25 -       unsigned int            next_clk_idx;   /* Next clock index */
  26 -       unsigned int            cdivs[2];
  27 +       unsigned int            min_clk;        /* Min src clock freq */
  28 +       unsigned int            cur_clk;        /* Current src clock freq */
  29
  30         struct tasklet_struct   finish_tasklet; /* Tasklet structures */
  31
  32 @@ -216,7 +213,7 @@ struct bcm2835_host {
  33         u32                             delay_after_stop; /* minimum time between stop and subsequent data transfer */
  34         u32                             delay_after_this_stop; /* minimum time between this stop and subsequent data transfer */
  35         u32                             overclock_50;   /* frequency to use when 50MHz is requested (in MHz) */
  36 -       u32                             prev_overclock_50;
  37 +       u32                             overclock;      /* Current frequency if overclocked, else zero */
  38         u32                             pio_limit;      /* Maximum block count for PIO (0 = always DMA) */
  39
  40         u32                             sectors;        /* Cached card size in sectors */
  41 @@ -1512,35 +1509,10 @@ static irqreturn_t bcm2835_sdhost_irq(in
  42         return result;
  43  }
  44
  45 -static void bcm2835_sdhost_select_clock(struct bcm2835_host *host, int idx)
  46 -{
  47 -       unsigned int clock = host->clocks[idx];
  48 -       unsigned int cdiv = host->cdivs[idx];
  49 -
  50 -       host->mmc->actual_clock = clock;
  51 -       host->ns_per_fifo_word = (1000000000/clock) *
  52 -               ((host->mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
  53 -
  54 -       host->cdiv = cdiv;
  55 -       bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
  56 -
  57 -       /* Set the timeout to 500ms */
  58 -       bcm2835_sdhost_write(host, clock/2, SDTOUT);
  59 -
  60 -       host->cur_clk_idx = host->next_clk_idx = idx;
  61 -
  62 -       if (host->debug)
  63 -               pr_info("%s: clock=%d -> src_clk=%d, cdiv=%x (actual %d)\n",
  64 -                       mmc_hostname(host->mmc), host->clock,
  65 -                       host->src_clks[idx], host->cdiv,
  66 -                       host->mmc->actual_clock);
  67 -}
  68 -
  69  void bcm2835_sdhost_set_clock(struct bcm2835_host *host)
  70  {
  71         int div = 0; /* Initialized for compiler warning */
  72         unsigned int clock = host->clock;
  73 -       int clk_idx;
  74
  75         if (host->debug)
  76                 pr_info("%s: set_clock(%d)\n", mmc_hostname(host->mmc), clock);
  77 @@ -1581,45 +1553,53 @@ void bcm2835_sdhost_set_clock(struct bcm
  78             return;
  79         }
  80
  81 -       /* Calculate the clock divisors */
  82 -       for (clk_idx = 0; clk_idx <= host->variable_clock; clk_idx++)
  83 -       {
  84 -               unsigned int cur_clk = host->src_clks[clk_idx];
  85 -               unsigned int actual_clock;
  86 +       div = host->cur_clk / clock;
  87 +       if (div < 2)
  88 +               div = 2;
  89 +       if ((host->cur_clk / div) > clock)
  90 +               div++;
  91 +       div -= 2;
  92 +
  93 +       if (div > SDCDIV_MAX_CDIV)
  94 +           div = SDCDIV_MAX_CDIV;
  95 +
  96 +       clock = host->cur_clk / (div + 2);
  97 +       host->mmc->actual_clock = clock;
  98 +
  99 +       /* Calibrate some delays */
 100 +
 101 +       host->ns_per_fifo_word = (1000000000/clock) *
 102 +               ((host->mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
 103
 104 -               div = cur_clk / clock;
 105 -               if (div < 2)
 106 -                       div = 2;
 107 -               if ((cur_clk / div) > clock)
 108 -                       div++;
 109 -               div -= 2;
 110 -
 111 -               if (div > SDCDIV_MAX_CDIV)
 112 -                       div = SDCDIV_MAX_CDIV;
 113 -               actual_clock = cur_clk / (div + 2);
 114 -
 115 -               host->cdivs[clk_idx] = div;
 116 -               host->clocks[clk_idx] = actual_clock;
 117 -
 118 -               if (host->overclock_50 != host->prev_overclock_50) {
 119 -                       const char *clk_name = "";
 120 -                       if (host->variable_clock)
 121 -                               clk_name = clk_idx ? " (turbo)" : " (normal)";
 122 -                       if (actual_clock > host->clock)
 123 -                               pr_info("%s: overclocking to %dHz%s\n",
 124 -                                       mmc_hostname(host->mmc),
 125 -                                       actual_clock, clk_name);
 126 -                       else if ((host->overclock_50 < 50) && (clk_idx == 0))
 127 -                               pr_info("%s: cancelling overclock%s\n",
 128 -                                       mmc_hostname(host->mmc),
 129 -                                       host->variable_clock ? "s" : "");
 130 +       if (clock > host->clock) {
 131 +               /* Save the closest value, to make it easier
 132 +                  to reduce in the event of error */
 133 +               host->overclock_50 = (clock/MHZ);
 134 +
 135 +               if (clock != host->overclock) {
 136 +                       pr_warn("%s: overclocking to %dHz\n",
 137 +                               mmc_hostname(host->mmc), clock);
 138 +                       host->overclock = clock;
 139                 }
 140         }
 141 +       else if (host->overclock)
 142 +       {
 143 +               host->overclock = 0;
 144 +               if (clock == 50 * MHZ)
 145 +                       pr_warn("%s: cancelling overclock\n",
 146 +                               mmc_hostname(host->mmc));
 147 +       }
 148
 149 -       if (host->clock == 50*MHZ)
 150 -               host->prev_overclock_50 = host->overclock_50;
 151 +       host->cdiv = div;
 152 +       bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
 153
 154 -       bcm2835_sdhost_select_clock(host, host->cur_clk_idx);
 155 +       /* Set the timeout to 500ms */
 156 +       bcm2835_sdhost_write(host, host->mmc->actual_clock/2, SDTOUT);
 157 +
 158 +       if (host->debug)
 159 +               pr_info("%s: clock=%d -> cur_clk=%d, cdiv=%x (actual clock %d)\n",
 160 +                       mmc_hostname(host->mmc), host->clock,
 161 +                       host->cur_clk, host->cdiv, host->mmc->actual_clock);
 162  }
 163
 164  static void bcm2835_sdhost_request(struct mmc_host *mmc, struct mmc_request *mrq)
 165 @@ -1677,9 +1657,6 @@ static void bcm2835_sdhost_request(struc
 166
 167         spin_lock_irqsave(&host->lock, flags);
 168
 169 -       if (host->next_clk_idx != host->cur_clk_idx)
 170 -               bcm2835_sdhost_select_clock(host, host->next_clk_idx);
 171 -
 172         WARN_ON(host->mrq != NULL);
 173         host->mrq = mrq;
 174
 175 @@ -1742,7 +1719,11 @@ static int bcm2835_sdhost_cpufreq_callba
 176                                 return NOTIFY_BAD;
 177                         break;
 178                 case CPUFREQ_POSTCHANGE:
 179 -                       host->next_clk_idx = (freq->new > freq->old);
 180 +                       if (freq->new > freq->old)
 181 +                               host->cur_clk = host->max_clk;
 182 +                       else
 183 +                               host->cur_clk = host->min_clk;
 184 +                       bcm2835_sdhost_set_clock(host);
 185                         up(&host->cpufreq_semaphore);
 186                         break;
 187                 default:
 188 @@ -1782,11 +1763,8 @@ static void bcm2835_sdhost_set_ios(struc
 189                         ios->clock, ios->power_mode, ios->bus_width,
 190                         ios->timing, ios->signal_voltage, ios->drv_type);
 191
 192 -       if (ios->clock && (host->cur_clk_idx == -1)) {
 193 -               unsigned int cur_clk =
 194 -                       get_core_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
 195 -               host->cur_clk_idx = (cur_clk == host->src_clks[0]) ? 0 : 1;
 196 -       }
 197 +       if (ios->clock && !host->cur_clk)
 198 +               host->cur_clk = get_core_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
 199
 200         spin_lock_irqsave(&host->lock, flags);
 201
 202 @@ -1876,12 +1854,11 @@ static void bcm2835_sdhost_tasklet_finis
 203
 204         /* Drop the overclock after any data corruption, or after any
 205            error overclocked */
 206 -       if (host->clock > 50*MHZ) {
 207 +       if (host->overclock) {
 208                 if ((mrq->cmd && mrq->cmd->error) ||
 209                     (mrq->data && mrq->data->error) ||
 210                     (mrq->stop && mrq->stop->error)) {
 211 -                       host->overclock_50 = (host->clock/MHZ) - 1;
 212 -
 213 +                       host->overclock_50--;
 214                         pr_warn("%s: reducing overclock due to errors\n",
 215                                 mmc_hostname(host->mmc));
 216                         bcm2835_sdhost_set_clock(host);
 217 @@ -2045,7 +2022,7 @@ static int bcm2835_sdhost_probe(struct p
 218         struct bcm2835_host *host;
 219         struct mmc_host *mmc;
 220         const __be32 *addr;
 221 -       unsigned int max_clk, min_clk;
 222 +       unsigned int max_clk;
 223         int ret;
 224
 225         pr_debug("bcm2835_sdhost_probe\n");
 226 @@ -2151,8 +2128,12 @@ static int bcm2835_sdhost_probe(struct p
 227         else
 228                 mmc->caps |= MMC_CAP_4_BIT_DATA;
 229
 230 +       ret = bcm2835_sdhost_add_host(host);
 231 +       if (ret)
 232 +               goto err;
 233 +
 234         /* Query the core clock frequencies */
 235 -       min_clk = get_core_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
 236 +       host->min_clk = get_core_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
 237         max_clk = get_core_clock(RPI_FIRMWARE_GET_MAX_CLOCK_RATE);
 238         if (max_clk != host->max_clk) {
 239                 pr_warn("%s: Expected max clock %d, found %d\n",
 240 @@ -2160,24 +2141,19 @@ static int bcm2835_sdhost_probe(struct p
 241                 host->max_clk = max_clk;
 242         }
 243
 244 -       host->src_clks[0] = min_clk;
 245 -       host->cur_clk_idx = -1;
 246 -       if (max_clk != min_clk) {
 247 -               host->src_clks[1] = max_clk;
 248 +       if (host->min_clk != host->max_clk) {
 249                 host->cpufreq_nb.notifier_call =
 250                         bcm2835_sdhost_cpufreq_callback;
 251                 sema_init(&host->cpufreq_semaphore, 1);
 252                 cpufreq_register_notifier(&host->cpufreq_nb,
 253                                           CPUFREQ_TRANSITION_NOTIFIER);
 254                 host->variable_clock = 1;
 255 +               host->cur_clk = 0; /* Get this later */
 256         } else {
 257                 host->variable_clock = 0;
 258 +               host->cur_clk = host->max_clk;
 259         }
 260
 261 -       ret = bcm2835_sdhost_add_host(host);
 262 -       if (ret)
 263 -               goto err;
 264 -
 265         platform_set_drvdata(pdev, host);
 266
 267         pr_debug("bcm2835_sdhost_probe -> OK\n");