target/linux/xburst/patches-3.8/0013-MMC-JZ4740-Added-support-for-CPU-frequency-changing.patch

   1 From b95144c1b702f98c7902c75beb83f323701eb7c5 Mon Sep 17 00:00:00 2001
   2 From: Maarten ter Huurne <maarten@treewalker.org>
   3 Date: Sun, 19 Jun 2011 10:57:18 +0200
   4 Subject: [PATCH 13/21] MMC: JZ4740: Added support for CPU frequency changing.
   5
   6 The MSC device clock is stopped before the frequency change.
   7 After the change a new divider is computed and the clock is restarted.
   8 Also the frequency change is postponed if an I/O operation is in progress.
   9 ---
  10  drivers/mmc/host/jz4740_mmc.c |   69 +++++++++++++++++++++++++++++++++++++++-
  11  1 files changed, 67 insertions(+), 2 deletions(-)
  12
  13 --- a/drivers/mmc/host/jz4740_mmc.c
  14 +++ b/drivers/mmc/host/jz4740_mmc.c
  15 @@ -23,6 +23,7 @@
  16  #include <linux/delay.h>
  17  #include <linux/scatterlist.h>
  18  #include <linux/clk.h>
  19 +#include <linux/cpufreq.h>
  20
  21  #include <linux/bitops.h>
  22  #include <linux/gpio.h>
  23 @@ -685,6 +686,60 @@ static void jz4740_mmc_enable_sdio_irq(s
  24         jz4740_mmc_set_irq_enabled(host, JZ_MMC_IRQ_SDIO, enable);
  25  }
  26
  27 +#ifdef CONFIG_CPU_FREQ
  28 +
  29 +static struct jz4740_mmc_host *cpufreq_host;
  30 +
  31 +static int jz4740_mmc_cpufreq_transition(struct notifier_block *nb,
  32 +                                        unsigned long val, void *data)
  33 +{
  34 +       /* TODO: We only have to take action when the PLL freq changes:
  35 +                the main dividers have no influence on the MSC device clock. */
  36 +
  37 +       if (val == CPUFREQ_PRECHANGE) {
  38 +               mmc_claim_host(cpufreq_host->mmc);
  39 +               clk_disable(cpufreq_host->clk);
  40 +       } else if (val == CPUFREQ_POSTCHANGE) {
  41 +               struct mmc_ios *ios = &cpufreq_host->mmc->ios;
  42 +               if (ios->clock)
  43 +                       jz4740_mmc_set_clock_rate(cpufreq_host, ios->clock);
  44 +               if (ios->power_mode != MMC_POWER_OFF)
  45 +                       clk_enable(cpufreq_host->clk);
  46 +               mmc_release_host(cpufreq_host->mmc);
  47 +       }
  48 +       return 0;
  49 +}
  50 +
  51 +static struct notifier_block jz4740_mmc_cpufreq_nb = {
  52 +       .notifier_call = jz4740_mmc_cpufreq_transition,
  53 +};
  54 +
  55 +static inline int jz4740_mmc_cpufreq_register(struct jz4740_mmc_host *host)
  56 +{
  57 +       cpufreq_host = host;
  58 +       return cpufreq_register_notifier(&jz4740_mmc_cpufreq_nb,
  59 +                                        CPUFREQ_TRANSITION_NOTIFIER);
  60 +}
  61 +
  62 +static inline void jz4740_mmc_cpufreq_unregister(void)
  63 +{
  64 +       cpufreq_unregister_notifier(&jz4740_mmc_cpufreq_nb,
  65 +                                   CPUFREQ_TRANSITION_NOTIFIER);
  66 +}
  67 +
  68 +#else
  69 +
  70 +static inline int jz4740_mmc_cpufreq_register(struct jz4740_mmc_host *host)
  71 +{
  72 +       return 0;
  73 +}
  74 +
  75 +static inline void jz4740_mmc_cpufreq_unregister(void)
  76 +{
  77 +}
  78 +
  79 +#endif
  80 +
  81  static const struct mmc_host_ops jz4740_mmc_ops = {
  82         .request        = jz4740_mmc_request,
  83         .set_ios        = jz4740_mmc_set_ios,
  84 @@ -834,11 +889,18 @@ static int jz4740_mmc_probe(struct platf
  85                 goto err_free_host;
  86         }
  87
  88 +       ret = jz4740_mmc_cpufreq_register(host);
  89 +       if (ret) {
  90 +               dev_err(&pdev->dev,
  91 +                       "Failed to register cpufreq transition notifier\n");
  92 +               goto err_clk_put;
  93 +       }
  94 +
  95         host->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  96         if (!host->mem) {
  97                 ret = -ENOENT;
  98                 dev_err(&pdev->dev, "Failed to get base platform memory\n");
  99 -               goto err_clk_put;
 100 +               goto err_cpufreq_unreg;
 101         }
 102
 103         host->mem = request_mem_region(host->mem->start,
 104 @@ -846,7 +908,7 @@ static int jz4740_mmc_probe(struct platf
 105         if (!host->mem) {
 106                 ret = -EBUSY;
 107                 dev_err(&pdev->dev, "Failed to request base memory region\n");
 108 -               goto err_clk_put;
 109 +               goto err_cpufreq_unreg;
 110         }
 111
 112         host->base = ioremap_nocache(host->mem->start, resource_size(host->mem));
 113 @@ -929,6 +991,8 @@ err_iounmap:
 114         iounmap(host->base);
 115  err_release_mem_region:
 116         release_mem_region(host->mem->start, resource_size(host->mem));
 117 +err_cpufreq_unreg:
 118 +       jz4740_mmc_cpufreq_unregister();
 119  err_clk_put:
 120         clk_put(host->clk);
 121  err_free_host:
 122 @@ -958,6 +1022,7 @@ static int jz4740_mmc_remove(struct plat
 123         iounmap(host->base);
 124         release_mem_region(host->mem->start, resource_size(host->mem));
 125
 126 +       jz4740_mmc_cpufreq_unregister();
 127         clk_put(host->clk);
 128
 129         platform_set_drvdata(pdev, NULL);