LXR linux/arch/blackfin/mach-common/dpmc.c

   1/*
   2 * Copyright 2008 Analog Devices Inc.
   3 *
   4 * Licensed under the GPL-2 or later.
   5 */
   6
   7#include <linux/cdev.h>
   8#include <linux/device.h>
   9#include <linux/errno.h>
  10#include <linux/fs.h>
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/platform_device.h>
  14#include <linux/types.h>
  15#include <linux/cpufreq.h>
  16
  17#include <asm/delay.h>
  18#include <asm/dpmc.h>
  19
  20#define DRIVER_NAME "bfin dpmc"
  21
  22struct bfin_dpmc_platform_data *pdata;
  23
  24/**
  25 *      bfin_set_vlev - Update VLEV field in VR_CTL Reg.
  26 *                      Avoid BYPASS sequence
  27 */
  28static void bfin_set_vlev(unsigned int vlev)
  29{
  30        unsigned pll_lcnt;
  31
  32        pll_lcnt = bfin_read_PLL_LOCKCNT();
  33
  34        bfin_write_PLL_LOCKCNT(1);
  35        bfin_write_VR_CTL((bfin_read_VR_CTL() & ~VLEV) | vlev);
  36        bfin_write_PLL_LOCKCNT(pll_lcnt);
  37}
  38
  39/**
  40 *      bfin_get_vlev - Get CPU specific VLEV from platform device data
  41 */
  42static unsigned int bfin_get_vlev(unsigned int freq)
  43{
  44        int i;
  45
  46        if (!pdata)
  47                goto err_out;
  48
  49        freq >>= 16;
  50
  51        for (i = 0; i < pdata->tabsize; i++)
  52                if (freq <= (pdata->tuple_tab[i] & 0xFFFF))
  53                        return pdata->tuple_tab[i] >> 16;
  54
  55err_out:
  56        printk(KERN_WARNING "DPMC: No suitable CCLK VDDINT voltage pair found\n");
  57        return VLEV_120;
  58}
  59
  60#ifdef CONFIG_CPU_FREQ
  61# ifdef CONFIG_SMP
  62static void bfin_idle_this_cpu(void *info)
  63{
  64        unsigned long flags = 0;
  65        unsigned long iwr0, iwr1, iwr2;
  66        unsigned int cpu = smp_processor_id();
  67
  68        local_irq_save_hw(flags);
  69        bfin_iwr_set_sup0(&iwr0, &iwr1, &iwr2);
  70
  71        platform_clear_ipi(cpu, IRQ_SUPPLE_0);
  72        SSYNC();
  73        asm("IDLE;");
  74        bfin_iwr_restore(iwr0, iwr1, iwr2);
  75
  76        local_irq_restore_hw(flags);
  77}
  78
  79static void bfin_idle_cpu(void)
  80{
  81        smp_call_function(bfin_idle_this_cpu, NULL, 0);
  82}
  83
  84static void bfin_wakeup_cpu(void)
  85{
  86        unsigned int cpu;
  87        unsigned int this_cpu = smp_processor_id();
  88        cpumask_t mask;
  89
  90        cpumask_copy(&mask, cpu_online_mask);
  91        cpumask_clear_cpu(this_cpu, &mask);
  92        for_each_cpu(cpu, &mask)
  93                platform_send_ipi_cpu(cpu, IRQ_SUPPLE_0);
  94}
  95
  96# else
  97static void bfin_idle_cpu(void) {}
  98static void bfin_wakeup_cpu(void) {}
  99# endif
 100
 101static int
 102vreg_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data)
 103{
 104        struct cpufreq_freqs *freq = data;
 105
 106        if (freq->cpu != CPUFREQ_CPU)
 107                return 0;
 108
 109        if (val == CPUFREQ_PRECHANGE && freq->old < freq->new) {
 110                bfin_idle_cpu();
 111                bfin_set_vlev(bfin_get_vlev(freq->new));
 112                udelay(pdata->vr_settling_time); /* Wait until Volatge settled */
 113                bfin_wakeup_cpu();
 114        } else if (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) {
 115                bfin_idle_cpu();
 116                bfin_set_vlev(bfin_get_vlev(freq->new));
 117                bfin_wakeup_cpu();
 118        }
 119
 120        return 0;
 121}
 122
 123static struct notifier_block vreg_cpufreq_notifier_block = {
 124        .notifier_call  = vreg_cpufreq_notifier
 125};
 126#endif /* CONFIG_CPU_FREQ */
 127
 128/**
 129 *      bfin_dpmc_probe -
 130 *
 131 */
 132static int bfin_dpmc_probe(struct platform_device *pdev)
 133{
 134        if (pdev->dev.platform_data)
 135                pdata = pdev->dev.platform_data;
 136        else
 137                return -EINVAL;
 138
 139        return cpufreq_register_notifier(&vreg_cpufreq_notifier_block,
 140                                         CPUFREQ_TRANSITION_NOTIFIER);
 141}
 142
 143/**
 144 *      bfin_dpmc_remove -
 145 */
 146static int bfin_dpmc_remove(struct platform_device *pdev)
 147{
 148        pdata = NULL;
 149        return cpufreq_unregister_notifier(&vreg_cpufreq_notifier_block,
 150                                         CPUFREQ_TRANSITION_NOTIFIER);
 151}
 152
 153struct platform_driver bfin_dpmc_device_driver = {
 154        .probe   = bfin_dpmc_probe,
 155        .remove  = bfin_dpmc_remove,
 156        .driver  = {
 157                .name = DRIVER_NAME,
 158        }
 159};
 160module_platform_driver(bfin_dpmc_device_driver);
 161
 162MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 163MODULE_DESCRIPTION("cpu power management driver for Blackfin");
 164MODULE_LICENSE("GPL");
 165