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1da177e4
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1/*
2 * linux/arch/arm/mach-sa1100/cpu-sa1110.c
3 *
4 * Copyright (C) 2001 Russell King
5 *
1da177e4
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6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Note: there are two erratas that apply to the SA1110 here:
11 * 7 - SDRAM auto-power-up failure (rev A0)
12 * 13 - Corruption of internal register reads/writes following
13 * SDRAM reads (rev A0, B0, B1)
14 *
15 * We ignore rev. A0 and B0 devices; I don't think they're worth supporting.
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16 *
17 * The SDRAM type can be passed on the command line as cpu_sa1110.sdram=type
1da177e4 18 */
ba532011 19#include <linux/moduleparam.h>
1da177e4
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20#include <linux/types.h>
21#include <linux/kernel.h>
22#include <linux/sched.h>
23#include <linux/cpufreq.h>
24#include <linux/delay.h>
25#include <linux/init.h>
26
a09e64fb 27#include <mach/hardware.h>
1da177e4
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28#include <asm/mach-types.h>
29#include <asm/io.h>
30#include <asm/system.h>
31
32#include "generic.h"
33
34#undef DEBUG
35
36static struct cpufreq_driver sa1110_driver;
37
38struct sdram_params {
ba532011 39 const char name[16];
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40 u_char rows; /* bits */
41 u_char cas_latency; /* cycles */
42 u_char tck; /* clock cycle time (ns) */
43 u_char trcd; /* activate to r/w (ns) */
44 u_char trp; /* precharge to activate (ns) */
45 u_char twr; /* write recovery time (ns) */
46 u_short refresh; /* refresh time for array (us) */
47};
48
49struct sdram_info {
50 u_int mdcnfg;
51 u_int mdrefr;
52 u_int mdcas[3];
53};
54
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55static struct sdram_params sdram_tbl[] __initdata = {
56 { /* Toshiba TC59SM716 CL2 */
57 .name = "TC59SM716-CL2",
58 .rows = 12,
59 .tck = 10,
60 .trcd = 20,
61 .trp = 20,
62 .twr = 10,
63 .refresh = 64000,
64 .cas_latency = 2,
65 }, { /* Toshiba TC59SM716 CL3 */
66 .name = "TC59SM716-CL3",
67 .rows = 12,
68 .tck = 8,
69 .trcd = 20,
70 .trp = 20,
71 .twr = 8,
72 .refresh = 64000,
73 .cas_latency = 3,
74 }, { /* Samsung K4S641632D TC75 */
75 .name = "K4S641632D",
76 .rows = 14,
77 .tck = 9,
78 .trcd = 27,
79 .trp = 20,
80 .twr = 9,
81 .refresh = 64000,
82 .cas_latency = 3,
48e3becb 83 }, { /* Samsung K4S281632B-1H */
9f0f9313 84 .name = "K4S281632B-1H",
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85 .rows = 12,
86 .tck = 10,
87 .trp = 20,
88 .twr = 10,
89 .refresh = 64000,
90 .cas_latency = 3,
ba532011
RK
91 }, { /* Samsung KM416S4030CT */
92 .name = "KM416S4030CT",
93 .rows = 13,
94 .tck = 8,
95 .trcd = 24, /* 3 CLKs */
96 .trp = 24, /* 3 CLKs */
97 .twr = 16, /* Trdl: 2 CLKs */
98 .refresh = 64000,
99 .cas_latency = 3,
100 }, { /* Winbond W982516AH75L CL3 */
101 .name = "W982516AH75L",
102 .rows = 16,
103 .tck = 8,
104 .trcd = 20,
105 .trp = 20,
106 .twr = 8,
107 .refresh = 64000,
108 .cas_latency = 3,
109 },
1da177e4
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110};
111
112static struct sdram_params sdram_params;
113
114/*
115 * Given a period in ns and frequency in khz, calculate the number of
116 * cycles of frequency in period. Note that we round up to the next
117 * cycle, even if we are only slightly over.
118 */
119static inline u_int ns_to_cycles(u_int ns, u_int khz)
120{
121 return (ns * khz + 999999) / 1000000;
122}
123
124/*
125 * Create the MDCAS register bit pattern.
126 */
127static inline void set_mdcas(u_int *mdcas, int delayed, u_int rcd)
128{
129 u_int shift;
130
131 rcd = 2 * rcd - 1;
132 shift = delayed + 1 + rcd;
133
134 mdcas[0] = (1 << rcd) - 1;
135 mdcas[0] |= 0x55555555 << shift;
136 mdcas[1] = mdcas[2] = 0x55555555 << (shift & 1);
137}
138
139static void
140sdram_calculate_timing(struct sdram_info *sd, u_int cpu_khz,
141 struct sdram_params *sdram)
142{
143 u_int mem_khz, sd_khz, trp, twr;
144
145 mem_khz = cpu_khz / 2;
146 sd_khz = mem_khz;
147
148 /*
149 * If SDCLK would invalidate the SDRAM timings,
150 * run SDCLK at half speed.
151 *
152 * CPU steppings prior to B2 must either run the memory at
153 * half speed or use delayed read latching (errata 13).
154 */
155 if ((ns_to_cycles(sdram->tck, sd_khz) > 1) ||
156 (CPU_REVISION < CPU_SA1110_B2 && sd_khz < 62000))
157 sd_khz /= 2;
158
159 sd->mdcnfg = MDCNFG & 0x007f007f;
160
161 twr = ns_to_cycles(sdram->twr, mem_khz);
162
163 /* trp should always be >1 */
164 trp = ns_to_cycles(sdram->trp, mem_khz) - 1;
165 if (trp < 1)
166 trp = 1;
167
168 sd->mdcnfg |= trp << 8;
169 sd->mdcnfg |= trp << 24;
170 sd->mdcnfg |= sdram->cas_latency << 12;
171 sd->mdcnfg |= sdram->cas_latency << 28;
172 sd->mdcnfg |= twr << 14;
173 sd->mdcnfg |= twr << 30;
174
175 sd->mdrefr = MDREFR & 0xffbffff0;
176 sd->mdrefr |= 7;
177
178 if (sd_khz != mem_khz)
179 sd->mdrefr |= MDREFR_K1DB2;
180
181 /* initial number of '1's in MDCAS + 1 */
182 set_mdcas(sd->mdcas, sd_khz >= 62000, ns_to_cycles(sdram->trcd, mem_khz));
183
184#ifdef DEBUG
185 printk("MDCNFG: %08x MDREFR: %08x MDCAS0: %08x MDCAS1: %08x MDCAS2: %08x\n",
186 sd->mdcnfg, sd->mdrefr, sd->mdcas[0], sd->mdcas[1], sd->mdcas[2]);
187#endif
188}
189
190/*
191 * Set the SDRAM refresh rate.
192 */
193static inline void sdram_set_refresh(u_int dri)
194{
195 MDREFR = (MDREFR & 0xffff000f) | (dri << 4);
196 (void) MDREFR;
197}
198
199/*
200 * Update the refresh period. We do this such that we always refresh
201 * the SDRAMs within their permissible period. The refresh period is
202 * always a multiple of the memory clock (fixed at cpu_clock / 2).
203 *
204 * FIXME: we don't currently take account of burst accesses here,
205 * but neither do Intels DM nor Angel.
206 */
207static void
208sdram_update_refresh(u_int cpu_khz, struct sdram_params *sdram)
209{
210 u_int ns_row = (sdram->refresh * 1000) >> sdram->rows;
211 u_int dri = ns_to_cycles(ns_row, cpu_khz / 2) / 32;
212
213#ifdef DEBUG
214 mdelay(250);
215 printk("new dri value = %d\n", dri);
216#endif
217
218 sdram_set_refresh(dri);
219}
220
221/*
222 * Ok, set the CPU frequency.
223 */
224static int sa1110_target(struct cpufreq_policy *policy,
225 unsigned int target_freq,
226 unsigned int relation)
227{
228 struct sdram_params *sdram = &sdram_params;
229 struct cpufreq_freqs freqs;
230 struct sdram_info sd;
231 unsigned long flags;
232 unsigned int ppcr, unused;
233
234 switch(relation){
235 case CPUFREQ_RELATION_L:
236 ppcr = sa11x0_freq_to_ppcr(target_freq);
237 if (sa11x0_ppcr_to_freq(ppcr) > policy->max)
238 ppcr--;
239 break;
240 case CPUFREQ_RELATION_H:
241 ppcr = sa11x0_freq_to_ppcr(target_freq);
242 if (ppcr && (sa11x0_ppcr_to_freq(ppcr) > target_freq) &&
243 (sa11x0_ppcr_to_freq(ppcr-1) >= policy->min))
244 ppcr--;
245 break;
246 default:
247 return -EINVAL;
248 }
249
250 freqs.old = sa11x0_getspeed(0);
251 freqs.new = sa11x0_ppcr_to_freq(ppcr);
252 freqs.cpu = 0;
253
254 sdram_calculate_timing(&sd, freqs.new, sdram);
255
256#if 0
257 /*
258 * These values are wrong according to the SA1110 documentation
259 * and errata, but they seem to work. Need to get a storage
260 * scope on to the SDRAM signals to work out why.
261 */
262 if (policy->max < 147500) {
263 sd.mdrefr |= MDREFR_K1DB2;
264 sd.mdcas[0] = 0xaaaaaa7f;
265 } else {
266 sd.mdrefr &= ~MDREFR_K1DB2;
267 sd.mdcas[0] = 0xaaaaaa9f;
268 }
269 sd.mdcas[1] = 0xaaaaaaaa;
270 sd.mdcas[2] = 0xaaaaaaaa;
271#endif
272
273 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
274
275 /*
276 * The clock could be going away for some time. Set the SDRAMs
277 * to refresh rapidly (every 64 memory clock cycles). To get
278 * through the whole array, we need to wait 262144 mclk cycles.
279 * We wait 20ms to be safe.
280 */
281 sdram_set_refresh(2);
282 if (!irqs_disabled()) {
db579554 283 msleep(20);
1da177e4
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284 } else {
285 mdelay(20);
286 }
287
288 /*
289 * Reprogram the DRAM timings with interrupts disabled, and
290 * ensure that we are doing this within a complete cache line.
291 * This means that we won't access SDRAM for the duration of
292 * the programming.
293 */
294 local_irq_save(flags);
295 asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0));
296 udelay(10);
297 __asm__ __volatile__(" \n\
298 b 2f \n\
299 .align 5 \n\
3001: str %3, [%1, #0] @ MDCNFG \n\
301 str %4, [%1, #28] @ MDREFR \n\
302 str %5, [%1, #4] @ MDCAS0 \n\
303 str %6, [%1, #8] @ MDCAS1 \n\
304 str %7, [%1, #12] @ MDCAS2 \n\
305 str %8, [%2, #0] @ PPCR \n\
306 ldr %0, [%1, #0] \n\
307 b 3f \n\
3082: b 1b \n\
3093: nop \n\
310 nop"
311 : "=&r" (unused)
312 : "r" (&MDCNFG), "r" (&PPCR), "0" (sd.mdcnfg),
313 "r" (sd.mdrefr), "r" (sd.mdcas[0]),
314 "r" (sd.mdcas[1]), "r" (sd.mdcas[2]), "r" (ppcr));
315 local_irq_restore(flags);
316
317 /*
318 * Now, return the SDRAM refresh back to normal.
319 */
320 sdram_update_refresh(freqs.new, sdram);
321
322 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
323
324 return 0;
325}
326
327static int __init sa1110_cpu_init(struct cpufreq_policy *policy)
328{
329 if (policy->cpu != 0)
330 return -EINVAL;
331 policy->cur = policy->min = policy->max = sa11x0_getspeed(0);
1da177e4
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332 policy->cpuinfo.min_freq = 59000;
333 policy->cpuinfo.max_freq = 287000;
334 policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
335 return 0;
336}
337
338static struct cpufreq_driver sa1110_driver = {
339 .flags = CPUFREQ_STICKY,
340 .verify = sa11x0_verify_speed,
341 .target = sa1110_target,
342 .get = sa11x0_getspeed,
343 .init = sa1110_cpu_init,
344 .name = "sa1110",
345};
346
ba532011
RK
347static struct sdram_params *sa1110_find_sdram(const char *name)
348{
349 struct sdram_params *sdram;
350
351 for (sdram = sdram_tbl; sdram < sdram_tbl + ARRAY_SIZE(sdram_tbl); sdram++)
352 if (strcmp(name, sdram->name) == 0)
353 return sdram;
354
355 return NULL;
356}
357
358static char sdram_name[16];
359
1da177e4
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360static int __init sa1110_clk_init(void)
361{
ba532011
RK
362 struct sdram_params *sdram;
363 const char *name = sdram_name;
1da177e4 364
ba532011
RK
365 if (!name[0]) {
366 if (machine_is_assabet())
367 name = "TC59SM716-CL3";
1da177e4 368
ba532011
RK
369 if (machine_is_pt_system3())
370 name = "K4S641632D";
1da177e4 371
ba532011
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372 if (machine_is_h3100())
373 name = "KM416S4030CT";
48e3becb
KE
374 if (machine_is_jornada720())
375 name = "K4S281632B-1H";
ba532011 376 }
1da177e4 377
ba532011 378 sdram = sa1110_find_sdram(name);
1da177e4
LT
379 if (sdram) {
380 printk(KERN_DEBUG "SDRAM: tck: %d trcd: %d trp: %d"
381 " twr: %d refresh: %d cas_latency: %d\n",
382 sdram->tck, sdram->trcd, sdram->trp,
383 sdram->twr, sdram->refresh, sdram->cas_latency);
384
385 memcpy(&sdram_params, sdram, sizeof(sdram_params));
386
387 return cpufreq_register_driver(&sa1110_driver);
388 }
389
390 return 0;
391}
392
ba532011 393module_param_string(sdram, sdram_name, sizeof(sdram_name), 0);
1da177e4 394arch_initcall(sa1110_clk_init);