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 __devinit 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 __devexit 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  = __devexit_p(bfin_dpmc_remove),
156	.driver  = {
157		.name = DRIVER_NAME,
158	}
159};
160
161/**
162 *	bfin_dpmc_init - Init driver
163 */
164static int __init bfin_dpmc_init(void)
165{
166	return platform_driver_register(&bfin_dpmc_device_driver);
167}
168module_init(bfin_dpmc_init);
169
170/**
171 *	bfin_dpmc_exit - break down driver
172 */
173static void __exit bfin_dpmc_exit(void)
174{
175	platform_driver_unregister(&bfin_dpmc_device_driver);
176}
177module_exit(bfin_dpmc_exit);
178
179MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
180MODULE_DESCRIPTION("cpu power management driver for Blackfin");
181MODULE_LICENSE("GPL");
182