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
22 struct bfin_dpmc_platform_data *pdata;
23
24 /**
25 * bfin_set_vlev - Update VLEV field in VR_CTL Reg.
26 * Avoid BYPASS sequence
27 */
bfin_set_vlev(unsigned int vlev)28 static 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 */
bfin_get_vlev(unsigned int freq)42 static 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
55 err_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
bfin_idle_this_cpu(void * info)62 static 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
bfin_idle_cpu(void)79 static void bfin_idle_cpu(void)
80 {
81 smp_call_function(bfin_idle_this_cpu, NULL, 0);
82 }
83
bfin_wakeup_cpu(void)84 static 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
bfin_idle_cpu(void)97 static void bfin_idle_cpu(void) {}
bfin_wakeup_cpu(void)98 static void bfin_wakeup_cpu(void) {}
99 # endif
100
101 static int
vreg_cpufreq_notifier(struct notifier_block * nb,unsigned long val,void * data)102 vreg_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
123 static 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 */
bfin_dpmc_probe(struct platform_device * pdev)132 static 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 */
bfin_dpmc_remove(struct platform_device * pdev)146 static 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
153 struct 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 */
bfin_dpmc_init(void)164 static int __init bfin_dpmc_init(void)
165 {
166 return platform_driver_register(&bfin_dpmc_device_driver);
167 }
168 module_init(bfin_dpmc_init);
169
170 /**
171 * bfin_dpmc_exit - break down driver
172 */
bfin_dpmc_exit(void)173 static void __exit bfin_dpmc_exit(void)
174 {
175 platform_driver_unregister(&bfin_dpmc_device_driver);
176 }
177 module_exit(bfin_dpmc_exit);
178
179 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
180 MODULE_DESCRIPTION("cpu power management driver for Blackfin");
181 MODULE_LICENSE("GPL");
182