summaryrefslogtreecommitdiff
path: root/arch/blackfin/kernel/cplb-mpu/cplbmgr.c
blob: 8e1e9e9e9632680dc5c2e4b3a1dc9da8a54f28ae (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
/*
 *               Blackfin CPLB exception handling.
 *               Copyright 2004-2007 Analog Devices Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include <linux/module.h>
#include <linux/mm.h>

#include <asm/blackfin.h>
#include <asm/cacheflush.h>
#include <asm/cplb.h>
#include <asm/cplbinit.h>
#include <asm/mmu_context.h>

/*
 * WARNING
 *
 * This file is compiled with certain -ffixed-reg options.  We have to
 * make sure not to call any functions here that could clobber these
 * registers.
 */

int page_mask_nelts;
int page_mask_order;
unsigned long *current_rwx_mask[NR_CPUS];

int nr_dcplb_miss[NR_CPUS], nr_icplb_miss[NR_CPUS];
int nr_icplb_supv_miss[NR_CPUS], nr_dcplb_prot[NR_CPUS];
int nr_cplb_flush[NR_CPUS];

/*
 * Given the contents of the status register, return the index of the
 * CPLB that caused the fault.
 */
static inline int faulting_cplb_index(int status)
{
	int signbits = __builtin_bfin_norm_fr1x32(status & 0xFFFF);
	return 30 - signbits;
}

/*
 * Given the contents of the status register and the DCPLB_DATA contents,
 * return true if a write access should be permitted.
 */
static inline int write_permitted(int status, unsigned long data)
{
	if (status & FAULT_USERSUPV)
		return !!(data & CPLB_SUPV_WR);
	else
		return !!(data & CPLB_USER_WR);
}

/* Counters to implement round-robin replacement.  */
static int icplb_rr_index[NR_CPUS], dcplb_rr_index[NR_CPUS];

/*
 * Find an ICPLB entry to be evicted and return its index.
 */
static int evict_one_icplb(unsigned int cpu)
{
	int i;
	for (i = first_switched_icplb; i < MAX_CPLBS; i++)
		if ((icplb_tbl[cpu][i].data & CPLB_VALID) == 0)
			return i;
	i = first_switched_icplb + icplb_rr_index[cpu];
	if (i >= MAX_CPLBS) {
		i -= MAX_CPLBS - first_switched_icplb;
		icplb_rr_index[cpu] -= MAX_CPLBS - first_switched_icplb;
	}
	icplb_rr_index[cpu]++;
	return i;
}

static int evict_one_dcplb(unsigned int cpu)
{
	int i;
	for (i = first_switched_dcplb; i < MAX_CPLBS; i++)
		if ((dcplb_tbl[cpu][i].data & CPLB_VALID) == 0)
			return i;
	i = first_switched_dcplb + dcplb_rr_index[cpu];
	if (i >= MAX_CPLBS) {
		i -= MAX_CPLBS - first_switched_dcplb;
		dcplb_rr_index[cpu] -= MAX_CPLBS - first_switched_dcplb;
	}
	dcplb_rr_index[cpu]++;
	return i;
}

static noinline int dcplb_miss(unsigned int cpu)
{
	unsigned long addr = bfin_read_DCPLB_FAULT_ADDR();
	int status = bfin_read_DCPLB_STATUS();
	unsigned long *mask;
	int idx;
	unsigned long d_data;

	nr_dcplb_miss[cpu]++;

	d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
#ifdef CONFIG_BFIN_EXTMEM_DCACHEABLE
	if (bfin_addr_dcacheable(addr)) {
		d_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
# ifdef CONFIG_BFIN_EXTMEM_WRITETHROUGH
		d_data |= CPLB_L1_AOW | CPLB_WT;
# endif
	}
#endif

	if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
		addr = L2_START;
		d_data = L2_DMEMORY;
	} else if (addr >= physical_mem_end) {
		if (addr >= ASYNC_BANK0_BASE && addr < ASYNC_BANK3_BASE + ASYNC_BANK3_SIZE
		    && (status & FAULT_USERSUPV)) {
			addr &= ~0x3fffff;
			d_data &= ~PAGE_SIZE_4KB;
			d_data |= PAGE_SIZE_4MB;
		} else if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
		    && (status & (FAULT_RW | FAULT_USERSUPV)) == FAULT_USERSUPV) {
			addr &= ~(1 * 1024 * 1024 - 1);
			d_data &= ~PAGE_SIZE_4KB;
			d_data |= PAGE_SIZE_1MB;
		} else
			return CPLB_PROT_VIOL;
	} else if (addr >= _ramend) {
	    d_data |= CPLB_USER_RD | CPLB_USER_WR;
	} else {
		mask = current_rwx_mask[cpu];
		if (mask) {
			int page = addr >> PAGE_SHIFT;
			int idx = page >> 5;
			int bit = 1 << (page & 31);

			if (mask[idx] & bit)
				d_data |= CPLB_USER_RD;

			mask += page_mask_nelts;
			if (mask[idx] & bit)
				d_data |= CPLB_USER_WR;
		}
	}
	idx = evict_one_dcplb(cpu);

	addr &= PAGE_MASK;
	dcplb_tbl[cpu][idx].addr = addr;
	dcplb_tbl[cpu][idx].data = d_data;

	_disable_dcplb();
	bfin_write32(DCPLB_DATA0 + idx * 4, d_data);
	bfin_write32(DCPLB_ADDR0 + idx * 4, addr);
	_enable_dcplb();

	return 0;
}

static noinline int icplb_miss(unsigned int cpu)
{
	unsigned long addr = bfin_read_ICPLB_FAULT_ADDR();
	int status = bfin_read_ICPLB_STATUS();
	int idx;
	unsigned long i_data;

	nr_icplb_miss[cpu]++;

	/* If inside the uncached DMA region, fault.  */
	if (addr >= _ramend - DMA_UNCACHED_REGION && addr < _ramend)
		return CPLB_PROT_VIOL;

	if (status & FAULT_USERSUPV)
		nr_icplb_supv_miss[cpu]++;

	/*
	 * First, try to find a CPLB that matches this address.  If we
	 * find one, then the fact that we're in the miss handler means
	 * that the instruction crosses a page boundary.
	 */
	for (idx = first_switched_icplb; idx < MAX_CPLBS; idx++) {
		if (icplb_tbl[cpu][idx].data & CPLB_VALID) {
			unsigned long this_addr = icplb_tbl[cpu][idx].addr;
			if (this_addr <= addr && this_addr + PAGE_SIZE > addr) {
				addr += PAGE_SIZE;
				break;
			}
		}
	}

	i_data = CPLB_VALID | CPLB_PORTPRIO | PAGE_SIZE_4KB;

#ifdef CONFIG_BFIN_EXTMEM_ICACHEABLE
	/*
	 * Normal RAM, and possibly the reserved memory area, are
	 * cacheable.
	 */
	if (addr < _ramend ||
	    (addr < physical_mem_end && reserved_mem_icache_on))
		i_data |= CPLB_L1_CHBL | ANOMALY_05000158_WORKAROUND;
#endif

	if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
		addr = L2_START;
		i_data = L2_IMEMORY;
	} else if (addr >= physical_mem_end) {
		if (addr >= BOOT_ROM_START && addr < BOOT_ROM_START + BOOT_ROM_LENGTH
		    && (status & FAULT_USERSUPV)) {
			addr &= ~(1 * 1024 * 1024 - 1);
			i_data &= ~PAGE_SIZE_4KB;
			i_data |= PAGE_SIZE_1MB;
		} else
		    return CPLB_PROT_VIOL;
	} else if (addr >= _ramend) {
		i_data |= CPLB_USER_RD;
	} else {
		/*
		 * Two cases to distinguish - a supervisor access must
		 * necessarily be for a module page; we grant it
		 * unconditionally (could do better here in the future).
		 * Otherwise, check the x bitmap of the current process.
		 */
		if (!(status & FAULT_USERSUPV)) {
			unsigned long *mask = current_rwx_mask[cpu];

			if (mask) {
				int page = addr >> PAGE_SHIFT;
				int idx = page >> 5;
				int bit = 1 << (page & 31);

				mask += 2 * page_mask_nelts;
				if (mask[idx] & bit)
					i_data |= CPLB_USER_RD;
			}
		}
	}
	idx = evict_one_icplb(cpu);
	addr &= PAGE_MASK;
	icplb_tbl[cpu][idx].addr = addr;
	icplb_tbl[cpu][idx].data = i_data;

	_disable_icplb();
	bfin_write32(ICPLB_DATA0 + idx * 4, i_data);
	bfin_write32(ICPLB_ADDR0 + idx * 4, addr);
	_enable_icplb();

	return 0;
}

static noinline int dcplb_protection_fault(unsigned int cpu)
{
	int status = bfin_read_DCPLB_STATUS();

	nr_dcplb_prot[cpu]++;

	if (status & FAULT_RW) {
		int idx = faulting_cplb_index(status);
		unsigned long data = dcplb_tbl[cpu][idx].data;
		if (!(data & CPLB_WT) && !(data & CPLB_DIRTY) &&
		    write_permitted(status, data)) {
			data |= CPLB_DIRTY;
			dcplb_tbl[cpu][idx].data = data;
			bfin_write32(DCPLB_DATA0 + idx * 4, data);
			return 0;
		}
	}
	return CPLB_PROT_VIOL;
}

int cplb_hdr(int seqstat, struct pt_regs *regs)
{
	int cause = seqstat & 0x3f;
	unsigned int cpu = raw_smp_processor_id();
	switch (cause) {
	case 0x23:
		return dcplb_protection_fault(cpu);
	case 0x2C:
		return icplb_miss(cpu);
	case 0x26:
		return dcplb_miss(cpu);
	default:
		return 1;
	}
}

void flush_switched_cplbs(unsigned int cpu)
{
	int i;
	unsigned long flags;

	nr_cplb_flush[cpu]++;

	local_irq_save_hw(flags);
	_disable_icplb();
	for (i = first_switched_icplb; i < MAX_CPLBS; i++) {
		icplb_tbl[cpu][i].data = 0;
		bfin_write32(ICPLB_DATA0 + i * 4, 0);
	}
	_enable_icplb();

	_disable_dcplb();
	for (i = first_switched_dcplb; i < MAX_CPLBS; i++) {
		dcplb_tbl[cpu][i].data = 0;
		bfin_write32(DCPLB_DATA0 + i * 4, 0);
	}
	_enable_dcplb();
	local_irq_restore_hw(flags);

}

void set_mask_dcplbs(unsigned long *masks, unsigned int cpu)
{
	int i;
	unsigned long addr = (unsigned long)masks;
	unsigned long d_data;
	unsigned long flags;

	if (!masks) {
		current_rwx_mask[cpu] = masks;
		return;
	}

	local_irq_save_hw(flags);
	current_rwx_mask[cpu] = masks;

	if (L2_LENGTH && addr >= L2_START && addr < L2_START + L2_LENGTH) {
		addr = L2_START;
		d_data = L2_DMEMORY;
	} else {
		d_data = CPLB_SUPV_WR | CPLB_VALID | CPLB_DIRTY | PAGE_SIZE_4KB;
#ifdef CONFIG_BFIN_EXTMEM_DCACHEABLE
		d_data |= CPLB_L1_CHBL;
# ifdef CONFIG_BFIN_EXTMEM_WRITETHROUGH
		d_data |= CPLB_L1_AOW | CPLB_WT;
# endif
#endif
	}

	_disable_dcplb();
	for (i = first_mask_dcplb; i < first_switched_dcplb; i++) {
		dcplb_tbl[cpu][i].addr = addr;
		dcplb_tbl[cpu][i].data = d_data;
		bfin_write32(DCPLB_DATA0 + i * 4, d_data);
		bfin_write32(DCPLB_ADDR0 + i * 4, addr);
		addr += PAGE_SIZE;
	}
	_enable_dcplb();
	local_irq_restore_hw(flags);
}