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

   1 From 664ffae1f5e89a69f12f83717c2a7efccea008ca 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] Revert "bcm2835-sdhost: Precalc divisors and overclocks"
   5
   6 This reverts commit 20260462773366a5734e5268dae0a4c179a21a2d.
   7 ---
   8  drivers/mmc/host/bcm2835-sdhost.c | 152 ++++++++++++++++----------------------
   9  1 file changed, 64 insertions(+), 88 deletions(-)
  10
  11 --- a/drivers/mmc/host/bcm2835-sdhost.c
  12 +++ b/drivers/mmc/host/bcm2835-sdhost.c
  13 @@ -154,15 +154,12 @@ struct bcm2835_host {
  14         u32                     pio_timeout;    /* In jiffies */
  15
  16         int                     clock;          /* Current clock speed */
  17 -       int                     clocks[2];
  18
  19         bool                    slow_card;      /* Force 11-bit divisor */
  20
  21         unsigned int            max_clk;        /* Max src clock freq */
  22 -       unsigned int            src_clks[2];    /* Min/max src clock freqs */
  23 -       unsigned int            cur_clk_idx;    /* Index of current clock */
  24 -       unsigned int            next_clk_idx;   /* Next clock index */
  25 -       unsigned int            cdivs[2];
  26 +       unsigned int            min_clk;        /* Min src clock freq */
  27 +       unsigned int            cur_clk;        /* Current src clock freq */
  28
  29         struct tasklet_struct   finish_tasklet; /* Tasklet structures */
  30
  31 @@ -216,7 +213,7 @@ struct bcm2835_host {
  32         u32                             delay_after_stop; /* minimum time between stop and subsequent data transfer */
  33         u32                             delay_after_this_stop; /* minimum time between this stop and subsequent data transfer */
  34         u32                             overclock_50;   /* frequency to use when 50MHz is requested (in MHz) */
  35 -       u32                             prev_overclock_50;
  36 +       u32                             overclock;      /* Current frequency if overclocked, else zero */
  37         u32                             pio_limit;      /* Maximum block count for PIO (0 = always DMA) */
  38
  39         u32                             sectors;        /* Cached card size in sectors */
  40 @@ -1512,35 +1509,10 @@ static irqreturn_t bcm2835_sdhost_irq(in
  41         return result;
  42  }
  43
  44 -static void bcm2835_sdhost_select_clock(struct bcm2835_host *host, int idx)
  45 -{
  46 -       unsigned int clock = host->clocks[idx];
  47 -       unsigned int cdiv = host->cdivs[idx];
  48 -
  49 -       host->mmc->actual_clock = clock;
  50 -       host->ns_per_fifo_word = (1000000000/clock) *
  51 -               ((host->mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
  52 -
  53 -       host->cdiv = cdiv;
  54 -       bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
  55 -
  56 -       /* Set the timeout to 500ms */
  57 -       bcm2835_sdhost_write(host, clock/2, SDTOUT);
  58 -
  59 -       host->cur_clk_idx = host->next_clk_idx = idx;
  60 -
  61 -       if (host->debug)
  62 -               pr_info("%s: clock=%d -> src_clk=%d, cdiv=%x (actual %d)\n",
  63 -                       mmc_hostname(host->mmc), host->clock,
  64 -                       host->src_clks[idx], host->cdiv,
  65 -                       host->mmc->actual_clock);
  66 -}
  67 -
  68  void bcm2835_sdhost_set_clock(struct bcm2835_host *host)
  69  {
  70         int div = 0; /* Initialized for compiler warning */
  71         unsigned int clock = host->clock;
  72 -       int clk_idx;
  73
  74         if (host->debug)
  75                 pr_info("%s: set_clock(%d)\n", mmc_hostname(host->mmc), clock);
  76 @@ -1581,45 +1553,53 @@ void bcm2835_sdhost_set_clock(struct bcm
  77             return;
  78         }
  79
  80 -       /* Calculate the clock divisors */
  81 -       for (clk_idx = 0; clk_idx <= host->variable_clock; clk_idx++)
  82 -       {
  83 -               unsigned int cur_clk = host->src_clks[clk_idx];
  84 -               unsigned int actual_clock;
  85 +       div = host->cur_clk / clock;
  86 +       if (div < 2)
  87 +               div = 2;
  88 +       if ((host->cur_clk / div) > clock)
  89 +               div++;
  90 +       div -= 2;
  91 +
  92 +       if (div > SDCDIV_MAX_CDIV)
  93 +           div = SDCDIV_MAX_CDIV;
  94 +
  95 +       clock = host->cur_clk / (div + 2);
  96 +       host->mmc->actual_clock = clock;
  97 +
  98 +       /* Calibrate some delays */
  99 +
 100 +       host->ns_per_fifo_word = (1000000000/clock) *
 101 +               ((host->mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
 102
 103 -               div = cur_clk / clock;
 104 -               if (div < 2)
 105 -                       div = 2;
 106 -               if ((cur_clk / div) > clock)
 107 -                       div++;
 108 -               div -= 2;
 109 -
 110 -               if (div > SDCDIV_MAX_CDIV)
 111 -                       div = SDCDIV_MAX_CDIV;
 112 -               actual_clock = cur_clk / (div + 2);
 113 -
 114 -               host->cdivs[clk_idx] = div;
 115 -               host->clocks[clk_idx] = actual_clock;
 116 -
 117 -               if (host->overclock_50 != host->prev_overclock_50) {
 118 -                       const char *clk_name = "";
 119 -                       if (host->variable_clock)
 120 -                               clk_name = clk_idx ? " (turbo)" : " (normal)";
 121 -                       if (actual_clock > host->clock)
 122 -                               pr_info("%s: overclocking to %dHz%s\n",
 123 -                                       mmc_hostname(host->mmc),
 124 -                                       actual_clock, clk_name);
 125 -                       else if ((host->overclock_50 < 50) && (clk_idx == 0))
 126 -                               pr_info("%s: cancelling overclock%s\n",
 127 -                                       mmc_hostname(host->mmc),
 128 -                                       host->variable_clock ? "s" : "");
 129 +       if (clock > host->clock) {
 130 +               /* Save the closest value, to make it easier
 131 +                  to reduce in the event of error */
 132 +               host->overclock_50 = (clock/MHZ);
 133 +
 134 +               if (clock != host->overclock) {
 135 +                       pr_warn("%s: overclocking to %dHz\n",
 136 +                               mmc_hostname(host->mmc), clock);
 137 +                       host->overclock = clock;
 138                 }
 139         }
 140 +       else if (host->overclock)
 141 +       {
 142 +               host->overclock = 0;
 143 +               if (clock == 50 * MHZ)
 144 +                       pr_warn("%s: cancelling overclock\n",
 145 +                               mmc_hostname(host->mmc));
 146 +       }
 147
 148 -       if (host->clock == 50*MHZ)
 149 -               host->prev_overclock_50 = host->overclock_50;
 150 +       host->cdiv = div;
 151 +       bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
 152
 153 -       bcm2835_sdhost_select_clock(host, host->cur_clk_idx);
 154 +       /* Set the timeout to 500ms */
 155 +       bcm2835_sdhost_write(host, host->mmc->actual_clock/2, SDTOUT);
 156 +
 157 +       if (host->debug)
 158 +               pr_info("%s: clock=%d -> cur_clk=%d, cdiv=%x (actual clock %d)\n",
 159 +                       mmc_hostname(host->mmc), host->clock,
 160 +                       host->cur_clk, host->cdiv, host->mmc->actual_clock);
 161  }
 162
 163  static void bcm2835_sdhost_request(struct mmc_host *mmc, struct mmc_request *mrq)
 164 @@ -1677,9 +1657,6 @@ static void bcm2835_sdhost_request(struc
 165
 166         spin_lock_irqsave(&host->lock, flags);
 167
 168 -       if (host->next_clk_idx != host->cur_clk_idx)
 169 -               bcm2835_sdhost_select_clock(host, host->next_clk_idx);
 170 -
 171         WARN_ON(host->mrq != NULL);
 172         host->mrq = mrq;
 173
 174 @@ -1742,7 +1719,11 @@ static int bcm2835_sdhost_cpufreq_callba
 175                                 return NOTIFY_BAD;
 176                         break;
 177                 case CPUFREQ_POSTCHANGE:
 178 -                       host->next_clk_idx = (freq->new > freq->old);
 179 +                       if (freq->new > freq->old)
 180 +                               host->cur_clk = host->max_clk;
 181 +                       else
 182 +                               host->cur_clk = host->min_clk;
 183 +                       bcm2835_sdhost_set_clock(host);
 184                         up(&host->cpufreq_semaphore);
 185                         break;
 186                 default:
 187 @@ -1782,11 +1763,8 @@ static void bcm2835_sdhost_set_ios(struc
 188                         ios->clock, ios->power_mode, ios->bus_width,
 189                         ios->timing, ios->signal_voltage, ios->drv_type);
 190
 191 -       if (ios->clock && (host->cur_clk_idx == -1)) {
 192 -               unsigned int cur_clk =
 193 -                       get_core_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
 194 -               host->cur_clk_idx = (cur_clk == host->src_clks[0]) ? 0 : 1;
 195 -       }
 196 +       if (ios->clock && !host->cur_clk)
 197 +               host->cur_clk = get_core_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
 198
 199         spin_lock_irqsave(&host->lock, flags);
 200
 201 @@ -1876,12 +1854,11 @@ static void bcm2835_sdhost_tasklet_finis
 202
 203         /* Drop the overclock after any data corruption, or after any
 204            error overclocked */
 205 -       if (host->clock > 50*MHZ) {
 206 +       if (host->overclock) {
 207                 if ((mrq->cmd && mrq->cmd->error) ||
 208                     (mrq->data && mrq->data->error) ||
 209                     (mrq->stop && mrq->stop->error)) {
 210 -                       host->overclock_50 = (host->clock/MHZ) - 1;
 211 -
 212 +                       host->overclock_50--;
 213                         pr_warn("%s: reducing overclock due to errors\n",
 214                                 mmc_hostname(host->mmc));
 215                         bcm2835_sdhost_set_clock(host);
 216 @@ -2045,7 +2022,7 @@ static int bcm2835_sdhost_probe(struct p
 217         struct bcm2835_host *host;
 218         struct mmc_host *mmc;
 219         const __be32 *addr;
 220 -       unsigned int max_clk, min_clk;
 221 +       unsigned int max_clk;
 222         int ret;
 223
 224         pr_debug("bcm2835_sdhost_probe\n");
 225 @@ -2151,8 +2128,12 @@ static int bcm2835_sdhost_probe(struct p
 226         else
 227                 mmc->caps |= MMC_CAP_4_BIT_DATA;
 228
 229 +       ret = bcm2835_sdhost_add_host(host);
 230 +       if (ret)
 231 +               goto err;
 232 +
 233         /* Query the core clock frequencies */
 234 -       min_clk = get_core_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
 235 +       host->min_clk = get_core_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
 236         max_clk = get_core_clock(RPI_FIRMWARE_GET_MAX_CLOCK_RATE);
 237         if (max_clk != host->max_clk) {
 238                 pr_warn("%s: Expected max clock %d, found %d\n",
 239 @@ -2160,24 +2141,19 @@ static int bcm2835_sdhost_probe(struct p
 240                 host->max_clk = max_clk;
 241         }
 242
 243 -       host->src_clks[0] = min_clk;
 244 -       host->cur_clk_idx = -1;
 245 -       if (max_clk != min_clk) {
 246 -               host->src_clks[1] = max_clk;
 247 +       if (host->min_clk != host->max_clk) {
 248                 host->cpufreq_nb.notifier_call =
 249                         bcm2835_sdhost_cpufreq_callback;
 250                 sema_init(&host->cpufreq_semaphore, 1);
 251                 cpufreq_register_notifier(&host->cpufreq_nb,
 252                                           CPUFREQ_TRANSITION_NOTIFIER);
 253                 host->variable_clock = 1;
 254 +               host->cur_clk = 0; /* Get this later */
 255         } else {
 256                 host->variable_clock = 0;
 257 +               host->cur_clk = host->max_clk;
 258         }
 259
 260 -       ret = bcm2835_sdhost_add_host(host);
 261 -       if (ret)
 262 -               goto err;
 263 -
 264         platform_set_drvdata(pdev, host);
 265
 266         pr_debug("bcm2835_sdhost_probe -> OK\n");