[PATCH] powerpc: Merge kexec
[linux-2.6] / arch / powerpc / platforms / powermac / cpufreq_64.c
1 /*
2  *  Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
3  *  and                       Markus Demleitner <msdemlei@cl.uni-heidelberg.de>
4  *
5  * This program is free software; you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License version 2 as
7  * published by the Free Software Foundation.
8  *
9  * This driver adds basic cpufreq support for SMU & 970FX based G5 Macs,
10  * that is iMac G5 and latest single CPU desktop.
11  */
12
13 #include <linux/config.h>
14 #include <linux/module.h>
15 #include <linux/types.h>
16 #include <linux/errno.h>
17 #include <linux/kernel.h>
18 #include <linux/delay.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/cpufreq.h>
22 #include <linux/init.h>
23 #include <linux/completion.h>
24 #include <asm/prom.h>
25 #include <asm/machdep.h>
26 #include <asm/irq.h>
27 #include <asm/sections.h>
28 #include <asm/cputable.h>
29 #include <asm/time.h>
30 #include <asm/smu.h>
31
32 #undef DEBUG
33
34 #ifdef DEBUG
35 #define DBG(fmt...) printk(fmt)
36 #else
37 #define DBG(fmt...)
38 #endif
39
40 /* see 970FX user manual */
41
42 #define SCOM_PCR 0x0aa001                       /* PCR scom addr */
43
44 #define PCR_HILO_SELECT         0x80000000U     /* 1 = PCR, 0 = PCRH */
45 #define PCR_SPEED_FULL          0x00000000U     /* 1:1 speed value */
46 #define PCR_SPEED_HALF          0x00020000U     /* 1:2 speed value */
47 #define PCR_SPEED_QUARTER       0x00040000U     /* 1:4 speed value */
48 #define PCR_SPEED_MASK          0x000e0000U     /* speed mask */
49 #define PCR_SPEED_SHIFT         17
50 #define PCR_FREQ_REQ_VALID      0x00010000U     /* freq request valid */
51 #define PCR_VOLT_REQ_VALID      0x00008000U     /* volt request valid */
52 #define PCR_TARGET_TIME_MASK    0x00006000U     /* target time */
53 #define PCR_STATLAT_MASK        0x00001f00U     /* STATLAT value */
54 #define PCR_SNOOPLAT_MASK       0x000000f0U     /* SNOOPLAT value */
55 #define PCR_SNOOPACC_MASK       0x0000000fU     /* SNOOPACC value */
56
57 #define SCOM_PSR 0x408001                       /* PSR scom addr */
58 /* warning: PSR is a 64 bits register */
59 #define PSR_CMD_RECEIVED        0x2000000000000000U   /* command received */
60 #define PSR_CMD_COMPLETED       0x1000000000000000U   /* command completed */
61 #define PSR_CUR_SPEED_MASK      0x0300000000000000U   /* current speed */
62 #define PSR_CUR_SPEED_SHIFT     (56)
63
64 /*
65  * The G5 only supports two frequencies (Quarter speed is not supported)
66  */
67 #define CPUFREQ_HIGH                  0
68 #define CPUFREQ_LOW                   1
69
70 static struct cpufreq_frequency_table g5_cpu_freqs[] = {
71         {CPUFREQ_HIGH,          0},
72         {CPUFREQ_LOW,           0},
73         {0,                     CPUFREQ_TABLE_END},
74 };
75
76 static struct freq_attr* g5_cpu_freqs_attr[] = {
77         &cpufreq_freq_attr_scaling_available_freqs,
78         NULL,
79 };
80
81 /* Power mode data is an array of the 32 bits PCR values to use for
82  * the various frequencies, retreived from the device-tree
83  */
84 static u32 *g5_pmode_data;
85 static int g5_pmode_max;
86 static int g5_pmode_cur;
87
88 static DECLARE_MUTEX(g5_switch_mutex);
89
90
91 static struct smu_sdbp_fvt *g5_fvt_table;       /* table of op. points */
92 static int g5_fvt_count;                        /* number of op. points */
93 static int g5_fvt_cur;                          /* current op. point */
94
95 /* ----------------- real hardware interface */
96
97 static void g5_switch_volt(int speed_mode)
98 {
99         struct smu_simple_cmd   cmd;
100
101         DECLARE_COMPLETION(comp);
102         smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, smu_done_complete,
103                          &comp, 'V', 'S', 'L', 'E', 'W',
104                          0xff, g5_fvt_cur+1, speed_mode);
105         wait_for_completion(&comp);
106 }
107
108 static int g5_switch_freq(int speed_mode)
109 {
110         struct cpufreq_freqs freqs;
111         int to;
112
113         if (g5_pmode_cur == speed_mode)
114                 return 0;
115
116         down(&g5_switch_mutex);
117
118         freqs.old = g5_cpu_freqs[g5_pmode_cur].frequency;
119         freqs.new = g5_cpu_freqs[speed_mode].frequency;
120         freqs.cpu = 0;
121
122         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
123
124         /* If frequency is going up, first ramp up the voltage */
125         if (speed_mode < g5_pmode_cur)
126                 g5_switch_volt(speed_mode);
127
128         /* Clear PCR high */
129         scom970_write(SCOM_PCR, 0);
130         /* Clear PCR low */
131         scom970_write(SCOM_PCR, PCR_HILO_SELECT | 0);
132         /* Set PCR low */
133         scom970_write(SCOM_PCR, PCR_HILO_SELECT |
134                       g5_pmode_data[speed_mode]);
135
136         /* Wait for completion */
137         for (to = 0; to < 10; to++) {
138                 unsigned long psr = scom970_read(SCOM_PSR);
139
140                 if ((psr & PSR_CMD_RECEIVED) == 0 &&
141                     (((psr >> PSR_CUR_SPEED_SHIFT) ^
142                       (g5_pmode_data[speed_mode] >> PCR_SPEED_SHIFT)) & 0x3)
143                     == 0)
144                         break;
145                 if (psr & PSR_CMD_COMPLETED)
146                         break;
147                 udelay(100);
148         }
149
150         /* If frequency is going down, last ramp the voltage */
151         if (speed_mode > g5_pmode_cur)
152                 g5_switch_volt(speed_mode);
153
154         g5_pmode_cur = speed_mode;
155         ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
156
157         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
158
159         up(&g5_switch_mutex);
160
161         return 0;
162 }
163
164 static int g5_query_freq(void)
165 {
166         unsigned long psr = scom970_read(SCOM_PSR);
167         int i;
168
169         for (i = 0; i <= g5_pmode_max; i++)
170                 if ((((psr >> PSR_CUR_SPEED_SHIFT) ^
171                       (g5_pmode_data[i] >> PCR_SPEED_SHIFT)) & 0x3) == 0)
172                         break;
173         return i;
174 }
175
176 /* ----------------- cpufreq bookkeeping */
177
178 static int g5_cpufreq_verify(struct cpufreq_policy *policy)
179 {
180         return cpufreq_frequency_table_verify(policy, g5_cpu_freqs);
181 }
182
183 static int g5_cpufreq_target(struct cpufreq_policy *policy,
184         unsigned int target_freq, unsigned int relation)
185 {
186         unsigned int    newstate = 0;
187
188         if (cpufreq_frequency_table_target(policy, g5_cpu_freqs,
189                         target_freq, relation, &newstate))
190                 return -EINVAL;
191
192         return g5_switch_freq(newstate);
193 }
194
195 static unsigned int g5_cpufreq_get_speed(unsigned int cpu)
196 {
197         return g5_cpu_freqs[g5_pmode_cur].frequency;
198 }
199
200 static int g5_cpufreq_cpu_init(struct cpufreq_policy *policy)
201 {
202         if (policy->cpu != 0)
203                 return -ENODEV;
204
205         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
206         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
207         policy->cur = g5_cpu_freqs[g5_query_freq()].frequency;
208         cpufreq_frequency_table_get_attr(g5_cpu_freqs, policy->cpu);
209
210         return cpufreq_frequency_table_cpuinfo(policy,
211                 g5_cpu_freqs);
212 }
213
214
215 static struct cpufreq_driver g5_cpufreq_driver = {
216         .name           = "powermac",
217         .owner          = THIS_MODULE,
218         .flags          = CPUFREQ_CONST_LOOPS,
219         .init           = g5_cpufreq_cpu_init,
220         .verify         = g5_cpufreq_verify,
221         .target         = g5_cpufreq_target,
222         .get            = g5_cpufreq_get_speed,
223         .attr           = g5_cpu_freqs_attr,
224 };
225
226
227 static int __init g5_cpufreq_init(void)
228 {
229         struct device_node *cpunode;
230         unsigned int psize, ssize;
231         struct smu_sdbp_header *shdr;
232         unsigned long max_freq;
233         u32 *valp;
234         int rc = -ENODEV;
235
236         /* Look for CPU and SMU nodes */
237         cpunode = of_find_node_by_type(NULL, "cpu");
238         if (!cpunode) {
239                 DBG("No CPU node !\n");
240                 return -ENODEV;
241         }
242
243         /* Check 970FX for now */
244         valp = (u32 *)get_property(cpunode, "cpu-version", NULL);
245         if (!valp) {
246                 DBG("No cpu-version property !\n");
247                 goto bail_noprops;
248         }
249         if (((*valp) >> 16) != 0x3c) {
250                 DBG("Wrong CPU version: %08x\n", *valp);
251                 goto bail_noprops;
252         }
253
254         /* Look for the powertune data in the device-tree */
255         g5_pmode_data = (u32 *)get_property(cpunode, "power-mode-data",&psize);
256         if (!g5_pmode_data) {
257                 DBG("No power-mode-data !\n");
258                 goto bail_noprops;
259         }
260         g5_pmode_max = psize / sizeof(u32) - 1;
261
262         /* Look for the FVT table */
263         shdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
264         if (!shdr)
265                 goto bail_noprops;
266         g5_fvt_table = (struct smu_sdbp_fvt *)&shdr[1];
267         ssize = (shdr->len * sizeof(u32)) - sizeof(struct smu_sdbp_header);
268         g5_fvt_count = ssize / sizeof(struct smu_sdbp_fvt);
269         g5_fvt_cur = 0;
270
271         /* Sanity checking */
272         if (g5_fvt_count < 1 || g5_pmode_max < 1)
273                 goto bail_noprops;
274
275         /*
276          * From what I see, clock-frequency is always the maximal frequency.
277          * The current driver can not slew sysclk yet, so we really only deal
278          * with powertune steps for now. We also only implement full freq and
279          * half freq in this version. So far, I haven't yet seen a machine
280          * supporting anything else.
281          */
282         valp = (u32 *)get_property(cpunode, "clock-frequency", NULL);
283         if (!valp)
284                 return -ENODEV;
285         max_freq = (*valp)/1000;
286         g5_cpu_freqs[0].frequency = max_freq;
287         g5_cpu_freqs[1].frequency = max_freq/2;
288
289         /* Check current frequency */
290         g5_pmode_cur = g5_query_freq();
291         if (g5_pmode_cur > 1)
292                 /* We don't support anything but 1:1 and 1:2, fixup ... */
293                 g5_pmode_cur = 1;
294
295         /* Force apply current frequency to make sure everything is in
296          * sync (voltage is right for example). Firmware may leave us with
297          * a strange setting ...
298          */
299         g5_switch_freq(g5_pmode_cur);
300
301         printk(KERN_INFO "Registering G5 CPU frequency driver\n");
302         printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
303                 g5_cpu_freqs[1].frequency/1000,
304                 g5_cpu_freqs[0].frequency/1000,
305                 g5_cpu_freqs[g5_pmode_cur].frequency/1000);
306
307         rc = cpufreq_register_driver(&g5_cpufreq_driver);
308
309         /* We keep the CPU node on hold... hopefully, Apple G5 don't have
310          * hotplug CPU with a dynamic device-tree ...
311          */
312         return rc;
313
314  bail_noprops:
315         of_node_put(cpunode);
316
317         return rc;
318 }
319
320 module_init(g5_cpufreq_init);
321
322
323 MODULE_LICENSE("GPL");