target/linux/s3c24xx/patches-2.6.26/1218-debug-add-glamo-drive-strength-module-param.patch.patch

   1 From e1bc0be9f95559ae154d24b353e404c781798da1 Mon Sep 17 00:00:00 2001
   2 From: Andy Green <andy@openmoko.com>
   3 Date: Fri, 25 Jul 2008 23:06:20 +0100
   4 Subject: [PATCH] debug-add-glamo-drive-strength-module-param.patch
   5  Suggested-by: Werner Almesberger <werner@openmoko.org>
   6
   7 This patch allows users to control two additional settings
   8 in Glamo MCI driver from kernel commandline or module
   9 parameters.
  10
  11
  12 First is Glamo drive strength on SD IOs including CLK.
  13 This ranges from 0 (weakest) to 3 (strongest).
  14
  15 echo 0 > /sys/module/glamo_mci/parameters/sd_drive
  16
  17 (Changes to this take effect on next SD Card transaction)
  18
  19 or, from kernel commandline
  20
  21 glamo_mci.sd_drive=0
  22
  23 On tests here with 0 strength, communication to SD card
  24 (shipped 512MB Sandisk) seemed fine, and a dd of 10MB
  25 urandom had the same md5 when written to cache as after
  26 a reboot.  I set the default to 2.
  27
  28
  29 Second is whether we allow SD_CLK when the SD interface
  30 is idle.
  31
  32 # stop the clock when we are idle (default)
  33 echo 0 > /sys/module/glamo_mci/parameters/sd_idleclk
  34
  35 # run the SD clock all the time
  36 echo 1 > /sys/module/glamo_mci/parameters/sd_idleclk
  37
  38 (changes take effect on next SD Card transaction)
  39
  40 From kernel commandline, eg:
  41
  42 glamo_mci.sd_idleclk=1
  43
  44 Normally you don't want to run the SD Clock all the time.
  45
  46
  47 Signed-off-by: Andy Green <andy@openmoko.com>
  48 ---
  49  drivers/mfd/glamo/glamo-mci.c |   59 +++++++++++++++++++++++++++++++---------
  50  1 files changed, 45 insertions(+), 14 deletions(-)
  51
  52 diff --git a/drivers/mfd/glamo/glamo-mci.c b/drivers/mfd/glamo/glamo-mci.c
  53 index 93f4074..4615033 100644
  54 --- a/drivers/mfd/glamo/glamo-mci.c
  55 +++ b/drivers/mfd/glamo/glamo-mci.c
  56 @@ -56,6 +56,32 @@ static void glamo_mci_send_request(struct mmc_host *mmc);
  57  static int sd_max_clk = 50000000 / 3;
  58  module_param(sd_max_clk, int, 0644);
  59
  60 +/*
  61 + * SD Signal drive strength
  62 + *
  63 + * you can override this on kernel commandline using
  64 + *
  65 + *   glamo_mci.sd_drive=0
  66 + *
  67 + * for example
  68 + */
  69 +
  70 +static int sd_drive = 2;
  71 +module_param(sd_drive, int, 0644);
  72 +
  73 +/*
  74 + * SD allow SD clock to run while idle
  75 + *
  76 + * you can override this on kernel commandline using
  77 + *
  78 + *   glamo_mci.sd_idleclk=0
  79 + *
  80 + * for example
  81 + */
  82 +
  83 +static int sd_idleclk = 0; /* disallow idle clock by default */
  84 +module_param(sd_idleclk, int, 0644);
  85 +
  86
  87
  88  unsigned char CRC7(u8 * pu8, int cnt)
  89 @@ -239,7 +265,9 @@ static int __glamo_mci_set_card_clock(struct glamo_mci_host *host, int freq,
  90                 if (division)
  91                         *division = 0xff;
  92
  93 -               __glamo_mci_fix_card_div(host, -1); /* clock off */
  94 +               if (!sd_idleclk)
  95 +                       /* clock off */
  96 +                       __glamo_mci_fix_card_div(host, -1);
  97         }
  98
  99         return real_rate;
 100 @@ -294,8 +322,9 @@ static void glamo_mci_irq(unsigned int irq, struct irq_desc *desc)
 101                 host->cmd_is_stop = 0;
 102         }
 103
 104 -       /* clock off */
 105 -       __glamo_mci_fix_card_div(host, -1);
 106 +       if (!sd_idleclk)
 107 +               /* clock off */
 108 +               __glamo_mci_fix_card_div(host, -1);
 109
 110  done:
 111         host->complete_what = COMPLETION_NONE;
 112 @@ -428,12 +457,10 @@ static int glamo_mci_send_command(struct glamo_mci_host *host,
 113         } else
 114                 writew(0xfff, host->base + GLAMO_REG_MMC_TIMEOUT);
 115
 116 -       /* Generate interrupt on txfer; drive strength max */
 117 -       writew_dly((readw_dly(host->base + GLAMO_REG_MMC_BASIC) & 0xfe) |
 118 +       /* Generate interrupt on txfer */
 119 +       writew_dly((readw_dly(host->base + GLAMO_REG_MMC_BASIC) & 0x3e) |
 120                    0x0800 | GLAMO_BASIC_MMC_NO_CLK_RD_WAIT |
 121 -                  GLAMO_BASIC_MMC_EN_COMPL_INT |
 122 -                  GLAMO_BASIC_MMC_EN_DR_STR0 |
 123 -                  GLAMO_BASIC_MMC_EN_DR_STR1,
 124 +                  GLAMO_BASIC_MMC_EN_COMPL_INT | (sd_drive << 6),
 125                    host->base + GLAMO_REG_MMC_BASIC);
 126
 127         /* send the command out on the wire */
 128 @@ -620,8 +647,9 @@ done:
 129         host->mrq = NULL;
 130         mmc_request_done(host->mmc, cmd->mrq);
 131  bail:
 132 -       /* stop the clock to card */
 133 -       __glamo_mci_fix_card_div(host, -1);
 134 +       if (!sd_idleclk)
 135 +               /* stop the clock to card */
 136 +               __glamo_mci_fix_card_div(host, -1);
 137  }
 138
 139  static void glamo_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 140 @@ -687,8 +715,9 @@ static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 141         host->real_rate = __glamo_mci_set_card_clock(host, ios->clock, &div);
 142         host->clk_div = div;
 143
 144 -       /* stop the clock to card, because we are idle until transfer */
 145 -       __glamo_mci_fix_card_div(host, -1);
 146 +       if (!sd_idleclk)
 147 +               /* stop the clock to card, because we are idle until transfer */
 148 +               __glamo_mci_fix_card_div(host, -1);
 149
 150         if ((ios->power_mode == MMC_POWER_ON) ||
 151             (ios->power_mode == MMC_POWER_UP)) {
 152 @@ -705,8 +734,10 @@ static void glamo_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 153         if (host->bus_width == MMC_BUS_WIDTH_4)
 154                 n = GLAMO_BASIC_MMC_EN_4BIT_DATA;
 155         writew_dly((readw_dly(host->base + GLAMO_REG_MMC_BASIC) &
 156 -                                         (~GLAMO_BASIC_MMC_EN_4BIT_DATA)) | n,
 157 -                                             host->base + GLAMO_REG_MMC_BASIC);
 158 +                                         (~(GLAMO_BASIC_MMC_EN_4BIT_DATA |
 159 +                                            GLAMO_BASIC_MMC_EN_DR_STR0 |
 160 +                                            GLAMO_BASIC_MMC_EN_DR_STR1))) | n |
 161 +                              sd_drive << 6, host->base + GLAMO_REG_MMC_BASIC);
 162  }
 163
 164
 165 --
 166 1.5.6.3
 167