aboutsummaryrefslogtreecommitdiff
path: root/arch/sh/kernel/cpu/init.c
blob: ecf83cd158dc38fefb91f2fa83cdb452cfa5c6bf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
/*
 * arch/sh/kernel/cpu/init.c
 *
 * CPU init code
 *
 * Copyright (C) 2002 - 2009  Paul Mundt
 * Copyright (C) 2003  Richard Curnow
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/log2.h>
#include <asm/mmu_context.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/cacheflush.h>
#include <asm/cache.h>
#include <asm/elf.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/sh_bios.h>
#include <asm/setup.h>

#ifdef CONFIG_SH_FPU
#define cpu_has_fpu	1
#else
#define cpu_has_fpu	0
#endif

#ifdef CONFIG_SH_DSP
#define cpu_has_dsp	1
#else
#define cpu_has_dsp	0
#endif

/*
 * Generic wrapper for command line arguments to disable on-chip
 * peripherals (nofpu, nodsp, and so forth).
 */
#define onchip_setup(x)					\
static int x##_disabled = !cpu_has_##x;			\
							\
static int x##_setup(char *opts)			\
{							\
	x##_disabled = 1;				\
	return 1;					\
}							\
__setup("no" __stringify(x), x##_setup);

onchip_setup(fpu);
onchip_setup(dsp);

#ifdef CONFIG_SPECULATIVE_EXECUTION
#define CPUOPM		0xff2f0000
#define CPUOPM_RABD	(1 << 5)

static void speculative_execution_init(void)
{
	/* Clear RABD */
	__raw_writel(__raw_readl(CPUOPM) & ~CPUOPM_RABD, CPUOPM);

	/* Flush the update */
	(void)__raw_readl(CPUOPM);
	ctrl_barrier();
}
#else
#define speculative_execution_init()	do { } while (0)
#endif

#ifdef CONFIG_CPU_SH4A
#define EXPMASK			0xff2f0004
#define EXPMASK_RTEDS		(1 << 0)
#define EXPMASK_BRDSSLP		(1 << 1)
#define EXPMASK_MMCAW		(1 << 4)

static void expmask_init(void)
{
	unsigned long expmask = __raw_readl(EXPMASK);

	/*
	 * Future proofing.
	 *
	 * Disable support for slottable sleep instruction, non-nop
	 * instructions in the rte delay slot, and associative writes to
	 * the memory-mapped cache array.
	 */
	expmask &= ~(EXPMASK_RTEDS | EXPMASK_BRDSSLP | EXPMASK_MMCAW);

	__raw_writel(expmask, EXPMASK);
	ctrl_barrier();
}
#else
#define expmask_init()	do { } while (0)
#endif

/* 2nd-level cache init */
void __attribute__ ((weak)) l2_cache_init(void)
{
}

/*
 * Generic first-level cache init
 */
#ifdef CONFIG_SUPERH32
static void cache_init(void)
{
	unsigned long ccr, flags;

	jump_to_uncached();
	ccr = __raw_readl(CCR);

	/*
	 * At this point we don't know whether the cache is enabled or not - a
	 * bootloader may have enabled it.  There are at least 2 things that
	 * could be dirty in the cache at this point:
	 * 1. kernel command line set up by boot loader
	 * 2. spilled registers from the prolog of this function
	 * => before re-initialising the cache, we must do a purge of the whole
	 * cache out to memory for safety.  As long as nothing is spilled
	 * during the loop to lines that have already been done, this is safe.
	 * - RPC
	 */
	if (ccr & CCR_CACHE_ENABLE) {
		unsigned long ways, waysize, addrstart;

		waysize = current_cpu_data.dcache.sets;

#ifdef CCR_CACHE_ORA
		/*
		 * If the OC is already in RAM mode, we only have
		 * half of the entries to flush..
		 */
		if (ccr & CCR_CACHE_ORA)
			waysize >>= 1;
#endif

		waysize <<= current_cpu_data.dcache.entry_shift;

#ifdef CCR_CACHE_EMODE
		/* If EMODE is not set, we only have 1 way to flush. */
		if (!(ccr & CCR_CACHE_EMODE))
			ways = 1;
		else
#endif
			ways = current_cpu_data.dcache.ways;

		addrstart = CACHE_OC_ADDRESS_ARRAY;
		do {
			unsigned long addr;

			for (addr = addrstart;
			     addr < addrstart + waysize;
			     addr += current_cpu_data.dcache.linesz)
				__raw_writel(0, addr);

			addrstart += current_cpu_data.dcache.way_incr;
		} while (--ways);
	}

	/*
	 * Default CCR values .. enable the caches
	 * and invalidate them immediately..
	 */
	flags = CCR_CACHE_ENABLE | CCR_CACHE_INVALIDATE;

#ifdef CCR_CACHE_EMODE
	/* Force EMODE if possible */
	if (current_cpu_data.dcache.ways > 1)
		flags |= CCR_CACHE_EMODE;
	else
		flags &= ~CCR_CACHE_EMODE;
#endif

#if defined(CONFIG_CACHE_WRITETHROUGH)
	/* Write-through */
	flags |= CCR_CACHE_WT;
#elif defined(CONFIG_CACHE_WRITEBACK)
	/* Write-back */
	flags |= CCR_CACHE_CB;
#else
	/* Off */
	flags &= ~CCR_CACHE_ENABLE;
#endif

	l2_cache_init();

	__raw_writel(flags, CCR);
	back_to_cached();
}
#else
#define cache_init()	do { } while (0)
#endif

#define CSHAPE(totalsize, linesize, assoc) \
	((totalsize & ~0xff) | (linesize << 4) | assoc)

#define CACHE_DESC_SHAPE(desc)	\
	CSHAPE((desc).way_size * (desc).ways, ilog2((desc).linesz), (desc).ways)

static void detect_cache_shape(void)
{
	l1d_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.dcache);

	if (current_cpu_data.dcache.flags & SH_CACHE_COMBINED)
		l1i_cache_shape = l1d_cache_shape;
	else
		l1i_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.icache);

	if (current_cpu_data.flags & CPU_HAS_L2_CACHE)
		l2_cache_shape = CACHE_DESC_SHAPE(current_cpu_data.scache);
	else
		l2_cache_shape = -1; /* No S-cache */
}

static void fpu_init(void)
{
	/* Disable the FPU */
	if (fpu_disabled && (current_cpu_data.flags & CPU_HAS_FPU)) {
		printk("FPU Disabled\n");
		current_cpu_data.flags &= ~CPU_HAS_FPU;
	}

	disable_fpu();
	clear_used_math();
}

#ifdef CONFIG_SH_DSP
static void release_dsp(void)
{
	unsigned long sr;

	/* Clear SR.DSP bit */
	__asm__ __volatile__ (
		"stc\tsr, %0\n\t"
		"and\t%1, %0\n\t"
		"ldc\t%0, sr\n\t"
		: "=&r" (sr)
		: "r" (~SR_DSP)
	);
}

static void dsp_init(void)
{
	unsigned long sr;

	/*
	 * Set the SR.DSP bit, wait for one instruction, and then read
	 * back the SR value.
	 */
	__asm__ __volatile__ (
		"stc\tsr, %0\n\t"
		"or\t%1, %0\n\t"
		"ldc\t%0, sr\n\t"
		"nop\n\t"
		"stc\tsr, %0\n\t"
		: "=&r" (sr)
		: "r" (SR_DSP)
	);

	/* If the DSP bit is still set, this CPU has a DSP */
	if (sr & SR_DSP)
		current_cpu_data.flags |= CPU_HAS_DSP;

	/* Disable the DSP */
	if (dsp_disabled && (current_cpu_data.flags & CPU_HAS_DSP)) {
		printk("DSP Disabled\n");
		current_cpu_data.flags &= ~CPU_HAS_DSP;
	}

	/* Now that we've determined the DSP status, clear the DSP bit. */
	release_dsp();
}
#else
static inline void dsp_init(void) { }
#endif /* CONFIG_SH_DSP */

/**
 * cpu_init
 *
 * This is our initial entry point for each CPU, and is invoked on the
 * boot CPU prior to calling start_kernel(). For SMP, a combination of
 * this and start_secondary() will bring up each processor to a ready
 * state prior to hand forking the idle loop.
 *
 * We do all of the basic processor init here, including setting up
 * the caches, FPU, DSP, etc. By the time start_kernel() is hit (and
 * subsequently platform_setup()) things like determining the CPU
 * subtype and initial configuration will all be done.
 *
 * Each processor family is still responsible for doing its own probing
 * and cache configuration in cpu_probe().
 */
asmlinkage void cpu_init(void)
{
	current_thread_info()->cpu = hard_smp_processor_id();

	/* First, probe the CPU */
	cpu_probe();

	if (current_cpu_data.type == CPU_SH_NONE)
		panic("Unknown CPU");

	/* First setup the rest of the I-cache info */
	current_cpu_data.icache.entry_mask = current_cpu_data.icache.way_incr -
				      current_cpu_data.icache.linesz;

	current_cpu_data.icache.way_size = current_cpu_data.icache.sets *
				    current_cpu_data.icache.linesz;

	/* And the D-cache too */
	current_cpu_data.dcache.entry_mask = current_cpu_data.dcache.way_incr -
				      current_cpu_data.dcache.linesz;

	current_cpu_data.dcache.way_size = current_cpu_data.dcache.sets *
				    current_cpu_data.dcache.linesz;

	/* Init the cache */
	cache_init();

	if (raw_smp_processor_id() == 0) {
		shm_align_mask = max_t(unsigned long,
				       current_cpu_data.dcache.way_size - 1,
				       PAGE_SIZE - 1);

		/* Boot CPU sets the cache shape */
		detect_cache_shape();
	}

	fpu_init();
	dsp_init();

	/*
	 * Initialize the per-CPU ASID cache very early, since the
	 * TLB flushing routines depend on this being setup.
	 */
	current_cpu_data.asid_cache = NO_CONTEXT;

	current_cpu_data.phys_bits = __in_29bit_mode() ? 29 : 32;

	speculative_execution_init();
	expmask_init();

	/* Do the rest of the boot processor setup */
	if (raw_smp_processor_id() == 0) {
		/* Save off the BIOS VBR, if there is one */
		sh_bios_vbr_init();

		/*
		 * Setup VBR for boot CPU. Secondary CPUs do this through
		 * start_secondary().
		 */
		per_cpu_trap_init();

		/*
		 * Boot processor to setup the FP and extended state
		 * context info.
		 */
		init_thread_xstate();
	}
}