Fix divide by zero error in build_clear_page() and build_copy_page()
[linux-2.6] / arch / mips / mm / c-tx39.c
1 /*
2  * r2300.c: R2000 and R3000 specific mmu/cache code.
3  *
4  * Copyright (C) 1996 David S. Miller (dm@engr.sgi.com)
5  *
6  * with a lot of changes to make this thing work for R3000s
7  * Tx39XX R4k style caches added. HK
8  * Copyright (C) 1998, 1999, 2000 Harald Koerfgen
9  * Copyright (C) 1998 Gleb Raiko & Vladimir Roganov
10  */
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/sched.h>
14 #include <linux/mm.h>
15
16 #include <asm/cacheops.h>
17 #include <asm/page.h>
18 #include <asm/pgtable.h>
19 #include <asm/mmu_context.h>
20 #include <asm/system.h>
21 #include <asm/isadep.h>
22 #include <asm/io.h>
23 #include <asm/bootinfo.h>
24 #include <asm/cpu.h>
25
26 /* For R3000 cores with R4000 style caches */
27 static unsigned long icache_size, dcache_size;          /* Size in bytes */
28
29 #include <asm/r4kcache.h>
30
31 extern int r3k_have_wired_reg;  /* in r3k-tlb.c */
32
33 /* This sequence is required to ensure icache is disabled immediately */
34 #define TX39_STOP_STREAMING() \
35 __asm__ __volatile__( \
36         ".set    push\n\t" \
37         ".set    noreorder\n\t" \
38         "b       1f\n\t" \
39         "nop\n\t" \
40         "1:\n\t" \
41         ".set pop" \
42         )
43
44 /* TX39H-style cache flush routines. */
45 static void tx39h_flush_icache_all(void)
46 {
47         unsigned long flags, config;
48
49         /* disable icache (set ICE#) */
50         local_irq_save(flags);
51         config = read_c0_conf();
52         write_c0_conf(config & ~TX39_CONF_ICE);
53         TX39_STOP_STREAMING();
54         blast_icache16();
55         write_c0_conf(config);
56         local_irq_restore(flags);
57 }
58
59 static void tx39h_dma_cache_wback_inv(unsigned long addr, unsigned long size)
60 {
61         /* Catch bad driver code */
62         BUG_ON(size == 0);
63
64         iob();
65         blast_inv_dcache_range(addr, addr + size);
66 }
67
68
69 /* TX39H2,TX39H3 */
70 static inline void tx39_blast_dcache_page(unsigned long addr)
71 {
72         if (current_cpu_type() != CPU_TX3912)
73                 blast_dcache16_page(addr);
74 }
75
76 static inline void tx39_blast_dcache_page_indexed(unsigned long addr)
77 {
78         blast_dcache16_page_indexed(addr);
79 }
80
81 static inline void tx39_blast_dcache(void)
82 {
83         blast_dcache16();
84 }
85
86 static inline void tx39_blast_icache_page(unsigned long addr)
87 {
88         unsigned long flags, config;
89         /* disable icache (set ICE#) */
90         local_irq_save(flags);
91         config = read_c0_conf();
92         write_c0_conf(config & ~TX39_CONF_ICE);
93         TX39_STOP_STREAMING();
94         blast_icache16_page(addr);
95         write_c0_conf(config);
96         local_irq_restore(flags);
97 }
98
99 static inline void tx39_blast_icache_page_indexed(unsigned long addr)
100 {
101         unsigned long flags, config;
102         /* disable icache (set ICE#) */
103         local_irq_save(flags);
104         config = read_c0_conf();
105         write_c0_conf(config & ~TX39_CONF_ICE);
106         TX39_STOP_STREAMING();
107         blast_icache16_page_indexed(addr);
108         write_c0_conf(config);
109         local_irq_restore(flags);
110 }
111
112 static inline void tx39_blast_icache(void)
113 {
114         unsigned long flags, config;
115         /* disable icache (set ICE#) */
116         local_irq_save(flags);
117         config = read_c0_conf();
118         write_c0_conf(config & ~TX39_CONF_ICE);
119         TX39_STOP_STREAMING();
120         blast_icache16();
121         write_c0_conf(config);
122         local_irq_restore(flags);
123 }
124
125 static void tx39__flush_cache_vmap(void)
126 {
127         tx39_blast_dcache();
128 }
129
130 static void tx39__flush_cache_vunmap(void)
131 {
132         tx39_blast_dcache();
133 }
134
135 static inline void tx39_flush_cache_all(void)
136 {
137         if (!cpu_has_dc_aliases)
138                 return;
139
140         tx39_blast_dcache();
141 }
142
143 static inline void tx39___flush_cache_all(void)
144 {
145         tx39_blast_dcache();
146         tx39_blast_icache();
147 }
148
149 static void tx39_flush_cache_mm(struct mm_struct *mm)
150 {
151         if (!cpu_has_dc_aliases)
152                 return;
153
154         if (cpu_context(smp_processor_id(), mm) != 0)
155                 tx39_blast_dcache();
156 }
157
158 static void tx39_flush_cache_range(struct vm_area_struct *vma,
159         unsigned long start, unsigned long end)
160 {
161         if (!cpu_has_dc_aliases)
162                 return;
163         if (!(cpu_context(smp_processor_id(), vma->vm_mm)))
164                 return;
165
166         tx39_blast_dcache();
167 }
168
169 static void tx39_flush_cache_page(struct vm_area_struct *vma, unsigned long page, unsigned long pfn)
170 {
171         int exec = vma->vm_flags & VM_EXEC;
172         struct mm_struct *mm = vma->vm_mm;
173         pgd_t *pgdp;
174         pud_t *pudp;
175         pmd_t *pmdp;
176         pte_t *ptep;
177
178         /*
179          * If ownes no valid ASID yet, cannot possibly have gotten
180          * this page into the cache.
181          */
182         if (cpu_context(smp_processor_id(), mm) == 0)
183                 return;
184
185         page &= PAGE_MASK;
186         pgdp = pgd_offset(mm, page);
187         pudp = pud_offset(pgdp, page);
188         pmdp = pmd_offset(pudp, page);
189         ptep = pte_offset(pmdp, page);
190
191         /*
192          * If the page isn't marked valid, the page cannot possibly be
193          * in the cache.
194          */
195         if (!(pte_val(*ptep) & _PAGE_PRESENT))
196                 return;
197
198         /*
199          * Doing flushes for another ASID than the current one is
200          * too difficult since stupid R4k caches do a TLB translation
201          * for every cache flush operation.  So we do indexed flushes
202          * in that case, which doesn't overly flush the cache too much.
203          */
204         if ((mm == current->active_mm) && (pte_val(*ptep) & _PAGE_VALID)) {
205                 if (cpu_has_dc_aliases || exec)
206                         tx39_blast_dcache_page(page);
207                 if (exec)
208                         tx39_blast_icache_page(page);
209
210                 return;
211         }
212
213         /*
214          * Do indexed flush, too much work to get the (possible) TLB refills
215          * to work correctly.
216          */
217         if (cpu_has_dc_aliases || exec)
218                 tx39_blast_dcache_page_indexed(page);
219         if (exec)
220                 tx39_blast_icache_page_indexed(page);
221 }
222
223 static void local_tx39_flush_data_cache_page(void * addr)
224 {
225         tx39_blast_dcache_page((unsigned long)addr);
226 }
227
228 static void tx39_flush_data_cache_page(unsigned long addr)
229 {
230         tx39_blast_dcache_page(addr);
231 }
232
233 static void tx39_flush_icache_range(unsigned long start, unsigned long end)
234 {
235         if (end - start > dcache_size)
236                 tx39_blast_dcache();
237         else
238                 protected_blast_dcache_range(start, end);
239
240         if (end - start > icache_size)
241                 tx39_blast_icache();
242         else {
243                 unsigned long flags, config;
244                 /* disable icache (set ICE#) */
245                 local_irq_save(flags);
246                 config = read_c0_conf();
247                 write_c0_conf(config & ~TX39_CONF_ICE);
248                 TX39_STOP_STREAMING();
249                 protected_blast_icache_range(start, end);
250                 write_c0_conf(config);
251                 local_irq_restore(flags);
252         }
253 }
254
255 static void tx39_dma_cache_wback_inv(unsigned long addr, unsigned long size)
256 {
257         unsigned long end;
258
259         if (((size | addr) & (PAGE_SIZE - 1)) == 0) {
260                 end = addr + size;
261                 do {
262                         tx39_blast_dcache_page(addr);
263                         addr += PAGE_SIZE;
264                 } while(addr != end);
265         } else if (size > dcache_size) {
266                 tx39_blast_dcache();
267         } else {
268                 blast_dcache_range(addr, addr + size);
269         }
270 }
271
272 static void tx39_dma_cache_inv(unsigned long addr, unsigned long size)
273 {
274         unsigned long end;
275
276         if (((size | addr) & (PAGE_SIZE - 1)) == 0) {
277                 end = addr + size;
278                 do {
279                         tx39_blast_dcache_page(addr);
280                         addr += PAGE_SIZE;
281                 } while(addr != end);
282         } else if (size > dcache_size) {
283                 tx39_blast_dcache();
284         } else {
285                 blast_inv_dcache_range(addr, addr + size);
286         }
287 }
288
289 static void tx39_flush_cache_sigtramp(unsigned long addr)
290 {
291         unsigned long ic_lsize = current_cpu_data.icache.linesz;
292         unsigned long dc_lsize = current_cpu_data.dcache.linesz;
293         unsigned long config;
294         unsigned long flags;
295
296         protected_writeback_dcache_line(addr & ~(dc_lsize - 1));
297
298         /* disable icache (set ICE#) */
299         local_irq_save(flags);
300         config = read_c0_conf();
301         write_c0_conf(config & ~TX39_CONF_ICE);
302         TX39_STOP_STREAMING();
303         protected_flush_icache_line(addr & ~(ic_lsize - 1));
304         write_c0_conf(config);
305         local_irq_restore(flags);
306 }
307
308 static __init void tx39_probe_cache(void)
309 {
310         unsigned long config;
311
312         config = read_c0_conf();
313
314         icache_size = 1 << (10 + ((config & TX39_CONF_ICS_MASK) >>
315                                   TX39_CONF_ICS_SHIFT));
316         dcache_size = 1 << (10 + ((config & TX39_CONF_DCS_MASK) >>
317                                   TX39_CONF_DCS_SHIFT));
318
319         current_cpu_data.icache.linesz = 16;
320         switch (current_cpu_type()) {
321         case CPU_TX3912:
322                 current_cpu_data.icache.ways = 1;
323                 current_cpu_data.dcache.ways = 1;
324                 current_cpu_data.dcache.linesz = 4;
325                 break;
326
327         case CPU_TX3927:
328                 current_cpu_data.icache.ways = 2;
329                 current_cpu_data.dcache.ways = 2;
330                 current_cpu_data.dcache.linesz = 16;
331                 break;
332
333         case CPU_TX3922:
334         default:
335                 current_cpu_data.icache.ways = 1;
336                 current_cpu_data.dcache.ways = 1;
337                 current_cpu_data.dcache.linesz = 16;
338                 break;
339         }
340 }
341
342 void __cpuinit tx39_cache_init(void)
343 {
344         extern void build_clear_page(void);
345         extern void build_copy_page(void);
346         unsigned long config;
347
348         config = read_c0_conf();
349         config &= ~TX39_CONF_WBON;
350         write_c0_conf(config);
351
352         tx39_probe_cache();
353
354         switch (current_cpu_type()) {
355         case CPU_TX3912:
356                 /* TX39/H core (writethru direct-map cache) */
357                 __flush_cache_vmap      = tx39__flush_cache_vmap;
358                 __flush_cache_vunmap    = tx39__flush_cache_vunmap;
359                 flush_cache_all = tx39h_flush_icache_all;
360                 __flush_cache_all       = tx39h_flush_icache_all;
361                 flush_cache_mm          = (void *) tx39h_flush_icache_all;
362                 flush_cache_range       = (void *) tx39h_flush_icache_all;
363                 flush_cache_page        = (void *) tx39h_flush_icache_all;
364                 flush_icache_range      = (void *) tx39h_flush_icache_all;
365
366                 flush_cache_sigtramp    = (void *) tx39h_flush_icache_all;
367                 local_flush_data_cache_page     = (void *) tx39h_flush_icache_all;
368                 flush_data_cache_page   = (void *) tx39h_flush_icache_all;
369
370                 _dma_cache_wback_inv    = tx39h_dma_cache_wback_inv;
371
372                 shm_align_mask          = PAGE_SIZE - 1;
373
374                 break;
375
376         case CPU_TX3922:
377         case CPU_TX3927:
378         default:
379                 /* TX39/H2,H3 core (writeback 2way-set-associative cache) */
380                 r3k_have_wired_reg = 1;
381                 write_c0_wired(0);      /* set 8 on reset... */
382                 /* board-dependent init code may set WBON */
383
384                 __flush_cache_vmap      = tx39__flush_cache_vmap;
385                 __flush_cache_vunmap    = tx39__flush_cache_vunmap;
386
387                 flush_cache_all = tx39_flush_cache_all;
388                 __flush_cache_all = tx39___flush_cache_all;
389                 flush_cache_mm = tx39_flush_cache_mm;
390                 flush_cache_range = tx39_flush_cache_range;
391                 flush_cache_page = tx39_flush_cache_page;
392                 flush_icache_range = tx39_flush_icache_range;
393
394                 flush_cache_sigtramp = tx39_flush_cache_sigtramp;
395                 local_flush_data_cache_page = local_tx39_flush_data_cache_page;
396                 flush_data_cache_page = tx39_flush_data_cache_page;
397
398                 _dma_cache_wback_inv = tx39_dma_cache_wback_inv;
399                 _dma_cache_wback = tx39_dma_cache_wback_inv;
400                 _dma_cache_inv = tx39_dma_cache_inv;
401
402                 shm_align_mask = max_t(unsigned long,
403                                        (dcache_size / current_cpu_data.dcache.ways) - 1,
404                                        PAGE_SIZE - 1);
405
406                 break;
407         }
408
409         current_cpu_data.icache.waysize = icache_size / current_cpu_data.icache.ways;
410         current_cpu_data.dcache.waysize = dcache_size / current_cpu_data.dcache.ways;
411
412         current_cpu_data.icache.sets =
413                 current_cpu_data.icache.waysize / current_cpu_data.icache.linesz;
414         current_cpu_data.dcache.sets =
415                 current_cpu_data.dcache.waysize / current_cpu_data.dcache.linesz;
416
417         if (current_cpu_data.dcache.waysize > PAGE_SIZE)
418                 current_cpu_data.dcache.flags |= MIPS_CACHE_ALIASES;
419
420         current_cpu_data.icache.waybit = 0;
421         current_cpu_data.dcache.waybit = 0;
422
423         printk("Primary instruction cache %ldkB, linesize %d bytes\n",
424                 icache_size >> 10, current_cpu_data.icache.linesz);
425         printk("Primary data cache %ldkB, linesize %d bytes\n",
426                 dcache_size >> 10, current_cpu_data.dcache.linesz);
427
428         build_clear_page();
429         build_copy_page();
430         tx39h_flush_icache_all();
431 }