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");