target/linux/s3c24xx/patches-2.6.24/1235-fix-force-sdcard-clk-off-when-idle.patch.patch

   1 From 5d70edcbe3ff5f6d5aef54ee9e278ad1ce431fd5 Mon Sep 17 00:00:00 2001
   2 From: Andy Green <andy@openmoko.com>
   3 Date: Thu, 17 Jul 2008 10:02:19 +0100
   4 Subject: [PATCH] fix-force-sdcard-clk-off-when-idle.patch
   5
   6 Existing Glamo bit for stopping SD Card Clock when there is no
   7 transfer taking place does not work.  This patch adds stuff around
   8 the transfer code to force the SD clock up when something is going on
   9 and down when it is idle.  This'll save a little power and noise ;-)
  10
  11 I tested it briefly and was able to SD Boot normally on Sandisk 512M.
  12 Wider testing is appreciated.
  13
  14 Signed-off-by: Andy Green <andy@openmoko.com>
  15 ---
  16  drivers/mfd/glamo/glamo-mci.c |  126 +++++++++++++++++++++++++++++------------
  17  1 files changed, 89 insertions(+), 37 deletions(-)
  18
  19 diff --git a/drivers/mfd/glamo/glamo-mci.c b/drivers/mfd/glamo/glamo-mci.c
  20 index f264a6c..350b47d 100644
  21 --- a/drivers/mfd/glamo/glamo-mci.c
  22 +++ b/drivers/mfd/glamo/glamo-mci.c
  23 @@ -20,6 +20,7 @@
  24  #include <linux/pcf50633.h>
  25  #include <linux/delay.h>
  26  #include <linux/interrupt.h>
  27 +#include <linux/spinlock.h>
  28
  29  #include <asm/dma.h>
  30  #include <asm/dma-mapping.h>
  31 @@ -32,6 +33,7 @@
  32  /* from glamo-core.c */
  33  extern struct glamo_mci_pdata glamo_mci_def_pdata;
  34
  35 +static spinlock_t clock_lock;
  36
  37  #define DRIVER_NAME "glamo-mci"
  38  #define RESSIZE(ressource) (((ressource)->end - (ressource)->start) + 1)
  39 @@ -164,6 +166,67 @@ static int do_pio_write(struct glamo_mci_host *host)
  40         return err;
  41  }
  42
  43 +static void __glamo_mci_fix_card_div(struct glamo_mci_host *host, int div)
  44 +{
  45 +       unsigned long flags;
  46 +
  47 +       spin_lock_irqsave(&clock_lock, flags);
  48 +
  49 +       if (div < 0) {
  50 +               /* stop clock - remove clock from divider input */
  51 +               writew(readw(glamo_mci_def_pdata.pglamo->base +
  52 +                    GLAMO_REG_CLOCK_GEN5_1) & (~GLAMO_CLOCK_GEN51_EN_DIV_TCLK),
  53 +                    glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN5_1);
  54 +       } else {
  55 +               /* set the nearest prescaler factor
  56 +               *
  57 +               * register shared with SCLK divisor -- no chance of race because
  58 +               * we don't use sensor interface
  59 +               */
  60 +               writew_dly((readw(glamo_mci_def_pdata.pglamo->base +
  61 +                               GLAMO_REG_CLOCK_GEN8) & 0xff00) | div,
  62 +                      glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN8);
  63 +               /* enable clock to divider input */
  64 +               writew_dly(readw(glamo_mci_def_pdata.pglamo->base +
  65 +                       GLAMO_REG_CLOCK_GEN5_1) | GLAMO_CLOCK_GEN51_EN_DIV_TCLK,
  66 +                    glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN5_1);
  67 +       }
  68 +
  69 +       spin_unlock_irqrestore(&clock_lock, flags);
  70 +}
  71 +
  72 +static int __glamo_mci_set_card_clock(struct glamo_mci_host *host, int freq,
  73 +                                                                 int *division)
  74 +{
  75 +       int div = 0;
  76 +       int real_rate = 0;
  77 +
  78 +       if (freq) {
  79 +               /* Set clock */
  80 +               for (div = 0; div < 256; div++) {
  81 +                       real_rate = host->clk_rate / (div + 1);
  82 +                       if (real_rate <= freq)
  83 +                               break;
  84 +               }
  85 +               if (div > 255)
  86 +                       div = 255;
  87 +
  88 +               if (division)
  89 +                       *division = div;
  90 +
  91 +               __glamo_mci_fix_card_div(host, div);
  92 +
  93 +       } else {
  94 +               /* stop clock */
  95 +               if (division)
  96 +                       *division = 0xff;
  97 +
  98 +               __glamo_mci_fix_card_div(host, -1); /* clock off */
  99 +       }
 100 +
 101 +       return real_rate;
 102 +}
 103 +
 104  static void glamo_mci_irq(unsigned int irq, struct irq_desc *desc)
 105  {
 106         struct glamo_mci_host *host = (struct glamo_mci_host *)
 107 @@ -212,6 +275,10 @@ static void glamo_mci_irq(unsigned int irq, struct irq_desc *desc)
 108                 glamo_mci_send_request(host->mmc);
 109                 host->cmd_is_stop = 0;
 110         }
 111 +
 112 +       /* clock off */
 113 +       __glamo_mci_fix_card_div(host, -1);
 114 +
 115  done:
 116         host->complete_what = COMPLETION_NONE;
 117         host->mrq = NULL;
 118 @@ -441,8 +508,11 @@ static void glamo_mci_send_request(struct mmc_host *mmc)
 119                  cmd->opcode, cmd->arg, cmd->data, cmd->mrq->stop,
 120                  cmd->flags);
 121
 122 +       /* resume requested clock rate */
 123 +       __glamo_mci_fix_card_div(host, host->clk_div);
 124 +
 125         if (glamo_mci_send_command(host, cmd))
 126 -               return;
 127 +               goto bail;
 128         /*
 129          * we must spin until response is ready or timed out
 130          * -- we don't get interrupts unless there is a bulk rx
 131 @@ -464,7 +534,7 @@ static void glamo_mci_send_request(struct mmc_host *mmc)
 132                 cmd->error = -EILSEQ;
 133
 134         if (host->cmd_is_stop)
 135 -               return;
 136 +               goto bail;
 137
 138         if (cmd->error) {
 139                 dev_info(&host->pdev->dev, "Error after cmd: 0x%x\n", status);
 140 @@ -516,10 +586,12 @@ static void glamo_mci_send_request(struct mmc_host *mmc)
 141                         if (cmd->data->error)
 142                                 cmd->data->error = -ETIMEDOUT;
 143                         dev_err(&host->pdev->dev, "Payload timeout\n");
 144 -                       return;
 145 +                       goto bail;
 146                 }
 147
 148 -               /* yay we are an interrupt controller! -- call the ISR */
 149 +               /* yay we are an interrupt controller! -- call the ISR
 150 +                * it will stop clock to card
 151 +                */
 152                 glamo_mci_irq(IRQ_GLAMO(GLAMO_IRQIDX_MMC),
 153                               irq_desc + IRQ_GLAMO(GLAMO_IRQIDX_MMC));
 154         }
 155 @@ -529,6 +601,12 @@ done:
 156         host->complete_what = COMPLETION_NONE;
 157         host->mrq = NULL;
 158         mmc_request_done(host->mmc, cmd->mrq);
 159 +       return;
 160 +
 161 +bail:
 162 +       /* stop the clock to card */
 163 +       __glamo_mci_fix_card_div(host, -1);
 164 +       return;
 165  }
 166
 167  static void glamo_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 168 @@ -556,11 +634,12 @@ static void glamo_mci_reset(struct glamo_mci_host *host)
 169                    glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_MMC);
 170  }
 171
 172 +
 173  static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 174  {
 175         struct glamo_mci_host *host = mmc_priv(mmc);
 176 -       int mci_psc = 0;
 177         int n = 0;
 178 +       int div;
 179
 180         /* Set power */
 181         switch(ios->power_mode) {
 182 @@ -590,43 +669,15 @@ static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 183         }
 184         host->power_mode_current = ios->power_mode;
 185
 186 -        /* Set clock */
 187 -/*     if (ios->clock) { */
 188 -       for (mci_psc = 0; mci_psc < 256; mci_psc++) {
 189 -               host->real_rate = host->clk_rate / (mci_psc + 1);
 190 -               if (host->real_rate <= ios->clock)
 191 -                       break;
 192 -       }
 193 -       if (mci_psc > 255)
 194 -               mci_psc = 255;
 195 -       host->clk_div = mci_psc;
 196 -       /* set the nearest prescaler factor
 197 -       *
 198 -       * register shared with SCLK divisor -- no chance of race because
 199 -       * we don't use sensor interface
 200 -       */
 201 -       writew_dly((readw(glamo_mci_def_pdata.pglamo->base +
 202 -                       GLAMO_REG_CLOCK_GEN8) & 0xff00) | host->clk_div,
 203 -               glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN8);
 204 -       /* enable clock to divider input */
 205 -       writew_dly(readw(glamo_mci_def_pdata.pglamo->base +
 206 -               GLAMO_REG_CLOCK_GEN5_1) | GLAMO_CLOCK_GEN51_EN_DIV_TCLK,
 207 -               glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN5_1);
 208 -#if 0
 209 -       } else { /* stop clock */
 210 -               host->real_rate = 0;
 211 -               /* remove clock from divider input */
 212 -               writew(readw(glamo_mci_def_pdata.pglamo->base +
 213 -                    GLAMO_REG_CLOCK_GEN5_1) & (~GLAMO_CLOCK_GEN51_EN_DIV_TCLK),
 214 -                    glamo_mci_def_pdata.pglamo->base + GLAMO_REG_CLOCK_GEN5_1);
 215 -       }
 216 -#endif
 217 +       host->real_rate = __glamo_mci_set_card_clock(host, ios->clock, &div);
 218 +       host->clk_div = div;
 219 +
 220         if ((ios->power_mode == MMC_POWER_ON) ||
 221             (ios->power_mode == MMC_POWER_UP)) {
 222                 dev_info(&host->pdev->dev,
 223                         "powered (vdd = %d) clk: %lukHz div=%d (req: %ukHz). "
 224                         "Bus width=%d\n",ios->vdd,
 225 -                       host->real_rate / 1000, mci_psc,
 226 +                       host->real_rate / 1000, host->real_rate,
 227                         ios->clock / 1000, ios->bus_width);
 228         } else
 229                 dev_info(&host->pdev->dev, "glamo_mci_set_ios: power down.\n");
 230 @@ -856,6 +907,7 @@ static struct platform_driver glamo_mci_driver =
 231
 232  static int __init glamo_mci_init(void)
 233  {
 234 +       spin_lock_init(&clock_lock);
 235         platform_driver_register(&glamo_mci_driver);
 236         return 0;
 237  }
 238 --
 239 1.5.6.5
 240