target/linux/xburst/patches-3.2/0013-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 diff --git a/drivers/mmc/host/jz4740_mmc.c b/drivers/mmc/host/jz4740_mmc.c
  14 index 74218ad..6e40f1b 100644
  15 --- a/drivers/mmc/host/jz4740_mmc.c
  16 +++ b/drivers/mmc/host/jz4740_mmc.c
  17 @@ -23,6 +23,7 @@
  18  #include <linux/delay.h>
  19  #include <linux/scatterlist.h>
  20  #include <linux/clk.h>
  21 +#include <linux/cpufreq.h>
  22
  23  #include <linux/bitops.h>
  24  #include <linux/gpio.h>
  25 @@ -685,6 +686,60 @@ static void jz4740_mmc_enable_sdio_irq(struct mmc_host *mmc, int enable)
  26         jz4740_mmc_set_irq_enabled(host, JZ_MMC_IRQ_SDIO, enable);
  27  }
  28
  29 +#ifdef CONFIG_CPU_FREQ
  30 +
  31 +static struct jz4740_mmc_host *cpufreq_host;
  32 +
  33 +static int jz4740_mmc_cpufreq_transition(struct notifier_block *nb,
  34 +                                        unsigned long val, void *data)
  35 +{
  36 +       /* TODO: We only have to take action when the PLL freq changes:
  37 +                the main dividers have no influence on the MSC device clock. */
  38 +
  39 +       if (val == CPUFREQ_PRECHANGE) {
  40 +               mmc_claim_host(cpufreq_host->mmc);
  41 +               clk_disable(cpufreq_host->clk);
  42 +       } else if (val == CPUFREQ_POSTCHANGE) {
  43 +               struct mmc_ios *ios = &cpufreq_host->mmc->ios;
  44 +               if (ios->clock)
  45 +                       jz4740_mmc_set_clock_rate(cpufreq_host, ios->clock);
  46 +               if (ios->power_mode != MMC_POWER_OFF)
  47 +                       clk_enable(cpufreq_host->clk);
  48 +               mmc_release_host(cpufreq_host->mmc);
  49 +       }
  50 +       return 0;
  51 +}
  52 +
  53 +static struct notifier_block jz4740_mmc_cpufreq_nb = {
  54 +       .notifier_call = jz4740_mmc_cpufreq_transition,
  55 +};
  56 +
  57 +static inline int jz4740_mmc_cpufreq_register(struct jz4740_mmc_host *host)
  58 +{
  59 +       cpufreq_host = host;
  60 +       return cpufreq_register_notifier(&jz4740_mmc_cpufreq_nb,
  61 +                                        CPUFREQ_TRANSITION_NOTIFIER);
  62 +}
  63 +
  64 +static inline void jz4740_mmc_cpufreq_unregister(void)
  65 +{
  66 +       cpufreq_unregister_notifier(&jz4740_mmc_cpufreq_nb,
  67 +                                   CPUFREQ_TRANSITION_NOTIFIER);
  68 +}
  69 +
  70 +#else
  71 +
  72 +static inline int jz4740_mmc_cpufreq_register(struct jz4740_mmc_host *host)
  73 +{
  74 +       return 0;
  75 +}
  76 +
  77 +static inline void jz4740_mmc_cpufreq_unregister(void)
  78 +{
  79 +}
  80 +
  81 +#endif
  82 +
  83  static const struct mmc_host_ops jz4740_mmc_ops = {
  84         .request        = jz4740_mmc_request,
  85         .set_ios        = jz4740_mmc_set_ios,
  86 @@ -834,11 +889,18 @@ static int __devinit jz4740_mmc_probe(struct platform_device* pdev)
  87                 goto err_free_host;
  88         }
  89
  90 +       ret = jz4740_mmc_cpufreq_register(host);
  91 +       if (ret) {
  92 +               dev_err(&pdev->dev,
  93 +                       "Failed to register cpufreq transition notifier\n");
  94 +               goto err_clk_put;
  95 +       }
  96 +
  97         host->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  98         if (!host->mem) {
  99                 ret = -ENOENT;
 100                 dev_err(&pdev->dev, "Failed to get base platform memory\n");
 101 -               goto err_clk_put;
 102 +               goto err_cpufreq_unreg;
 103         }
 104
 105         host->mem = request_mem_region(host->mem->start,
 106 @@ -846,7 +908,7 @@ static int __devinit jz4740_mmc_probe(struct platform_device* pdev)
 107         if (!host->mem) {
 108                 ret = -EBUSY;
 109                 dev_err(&pdev->dev, "Failed to request base memory region\n");
 110 -               goto err_clk_put;
 111 +               goto err_cpufreq_unreg;
 112         }
 113
 114         host->base = ioremap_nocache(host->mem->start, resource_size(host->mem));
 115 @@ -929,6 +991,8 @@ err_iounmap:
 116         iounmap(host->base);
 117  err_release_mem_region:
 118         release_mem_region(host->mem->start, resource_size(host->mem));
 119 +err_cpufreq_unreg:
 120 +       jz4740_mmc_cpufreq_unregister();
 121  err_clk_put:
 122         clk_put(host->clk);
 123  err_free_host:
 124 @@ -958,6 +1022,7 @@ static int __devexit jz4740_mmc_remove(struct platform_device *pdev)
 125         iounmap(host->base);
 126         release_mem_region(host->mem->start, resource_size(host->mem));
 127
 128 +       jz4740_mmc_cpufreq_unregister();
 129         clk_put(host->clk);
 130
 131         platform_set_drvdata(pdev, NULL);
 132 --
 133 1.7.5.4
 134