xref: /openbmc/linux/arch/sh/mm/pmb.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  * arch/sh/mm/pmb.c
3  *
4  * Privileged Space Mapping Buffer (PMB) Support.
5  *
6  * Copyright (C) 2005, 2006, 2007 Paul Mundt
7  *
8  * P1/P2 Section mapping definitions from map32.h, which was:
9  *
10  *	Copyright 2003 (c) Lineo Solutions,Inc.
11  *
12  * This file is subject to the terms and conditions of the GNU General Public
13  * License.  See the file "COPYING" in the main directory of this archive
14  * for more details.
15  */
16 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/slab.h>
20 #include <linux/bitops.h>
21 #include <linux/debugfs.h>
22 #include <linux/fs.h>
23 #include <linux/seq_file.h>
24 #include <linux/err.h>
25 #include <asm/system.h>
26 #include <asm/uaccess.h>
27 #include <asm/pgtable.h>
28 #include <asm/mmu.h>
29 #include <asm/io.h>
30 
31 #define NR_PMB_ENTRIES	16
32 
33 static struct kmem_cache *pmb_cache;
34 static unsigned long pmb_map;
35 
36 static struct pmb_entry pmb_init_map[] = {
37 	/* vpn         ppn         flags (ub/sz/c/wt) */
38 
39 	/* P1 Section Mappings */
40 	{ 0x80000000, 0x00000000, PMB_SZ_64M  | PMB_C, },
41 	{ 0x84000000, 0x04000000, PMB_SZ_64M  | PMB_C, },
42 	{ 0x88000000, 0x08000000, PMB_SZ_128M | PMB_C, },
43 	{ 0x90000000, 0x10000000, PMB_SZ_64M  | PMB_C, },
44 	{ 0x94000000, 0x14000000, PMB_SZ_64M  | PMB_C, },
45 	{ 0x98000000, 0x18000000, PMB_SZ_64M  | PMB_C, },
46 
47 	/* P2 Section Mappings */
48 	{ 0xa0000000, 0x00000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
49 	{ 0xa4000000, 0x04000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
50 	{ 0xa8000000, 0x08000000, PMB_UB | PMB_SZ_128M | PMB_WT, },
51 	{ 0xb0000000, 0x10000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
52 	{ 0xb4000000, 0x14000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
53 	{ 0xb8000000, 0x18000000, PMB_UB | PMB_SZ_64M  | PMB_WT, },
54 };
55 
56 static inline unsigned long mk_pmb_entry(unsigned int entry)
57 {
58 	return (entry & PMB_E_MASK) << PMB_E_SHIFT;
59 }
60 
61 static inline unsigned long mk_pmb_addr(unsigned int entry)
62 {
63 	return mk_pmb_entry(entry) | PMB_ADDR;
64 }
65 
66 static inline unsigned long mk_pmb_data(unsigned int entry)
67 {
68 	return mk_pmb_entry(entry) | PMB_DATA;
69 }
70 
71 static DEFINE_SPINLOCK(pmb_list_lock);
72 static struct pmb_entry *pmb_list;
73 
74 static inline void pmb_list_add(struct pmb_entry *pmbe)
75 {
76 	struct pmb_entry **p, *tmp;
77 
78 	p = &pmb_list;
79 	while ((tmp = *p) != NULL)
80 		p = &tmp->next;
81 
82 	pmbe->next = tmp;
83 	*p = pmbe;
84 }
85 
86 static inline void pmb_list_del(struct pmb_entry *pmbe)
87 {
88 	struct pmb_entry **p, *tmp;
89 
90 	for (p = &pmb_list; (tmp = *p); p = &tmp->next)
91 		if (tmp == pmbe) {
92 			*p = tmp->next;
93 			return;
94 		}
95 }
96 
97 struct pmb_entry *pmb_alloc(unsigned long vpn, unsigned long ppn,
98 			    unsigned long flags)
99 {
100 	struct pmb_entry *pmbe;
101 
102 	pmbe = kmem_cache_alloc(pmb_cache, GFP_KERNEL);
103 	if (!pmbe)
104 		return ERR_PTR(-ENOMEM);
105 
106 	pmbe->vpn	= vpn;
107 	pmbe->ppn	= ppn;
108 	pmbe->flags	= flags;
109 
110 	spin_lock_irq(&pmb_list_lock);
111 	pmb_list_add(pmbe);
112 	spin_unlock_irq(&pmb_list_lock);
113 
114 	return pmbe;
115 }
116 
117 void pmb_free(struct pmb_entry *pmbe)
118 {
119 	spin_lock_irq(&pmb_list_lock);
120 	pmb_list_del(pmbe);
121 	spin_unlock_irq(&pmb_list_lock);
122 
123 	kmem_cache_free(pmb_cache, pmbe);
124 }
125 
126 /*
127  * Must be in P2 for __set_pmb_entry()
128  */
129 int __set_pmb_entry(unsigned long vpn, unsigned long ppn,
130 		    unsigned long flags, int *entry)
131 {
132 	unsigned int pos = *entry;
133 
134 	if (unlikely(pos == PMB_NO_ENTRY))
135 		pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
136 
137 repeat:
138 	if (unlikely(pos > NR_PMB_ENTRIES))
139 		return -ENOSPC;
140 
141 	if (test_and_set_bit(pos, &pmb_map)) {
142 		pos = find_first_zero_bit(&pmb_map, NR_PMB_ENTRIES);
143 		goto repeat;
144 	}
145 
146 	ctrl_outl(vpn | PMB_V, mk_pmb_addr(pos));
147 
148 #ifdef CONFIG_SH_WRITETHROUGH
149 	/*
150 	 * When we are in 32-bit address extended mode, CCR.CB becomes
151 	 * invalid, so care must be taken to manually adjust cacheable
152 	 * translations.
153 	 */
154 	if (likely(flags & PMB_C))
155 		flags |= PMB_WT;
156 #endif
157 
158 	ctrl_outl(ppn | flags | PMB_V, mk_pmb_data(pos));
159 
160 	*entry = pos;
161 
162 	return 0;
163 }
164 
165 int set_pmb_entry(struct pmb_entry *pmbe)
166 {
167 	int ret;
168 
169 	jump_to_P2();
170 	ret = __set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &pmbe->entry);
171 	back_to_P1();
172 
173 	return ret;
174 }
175 
176 void clear_pmb_entry(struct pmb_entry *pmbe)
177 {
178 	unsigned int entry = pmbe->entry;
179 	unsigned long addr;
180 
181 	/*
182 	 * Don't allow clearing of wired init entries, P1 or P2 access
183 	 * without a corresponding mapping in the PMB will lead to reset
184 	 * by the TLB.
185 	 */
186 	if (unlikely(entry < ARRAY_SIZE(pmb_init_map) ||
187 		     entry >= NR_PMB_ENTRIES))
188 		return;
189 
190 	jump_to_P2();
191 
192 	/* Clear V-bit */
193 	addr = mk_pmb_addr(entry);
194 	ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);
195 
196 	addr = mk_pmb_data(entry);
197 	ctrl_outl(ctrl_inl(addr) & ~PMB_V, addr);
198 
199 	back_to_P1();
200 
201 	clear_bit(entry, &pmb_map);
202 }
203 
204 
205 static struct {
206 	unsigned long size;
207 	int flag;
208 } pmb_sizes[] = {
209 	{ .size	= 0x20000000, .flag = PMB_SZ_512M, },
210 	{ .size = 0x08000000, .flag = PMB_SZ_128M, },
211 	{ .size = 0x04000000, .flag = PMB_SZ_64M,  },
212 	{ .size = 0x01000000, .flag = PMB_SZ_16M,  },
213 };
214 
215 long pmb_remap(unsigned long vaddr, unsigned long phys,
216 	       unsigned long size, unsigned long flags)
217 {
218 	struct pmb_entry *pmbp;
219 	unsigned long wanted;
220 	int pmb_flags, i;
221 
222 	/* Convert typical pgprot value to the PMB equivalent */
223 	if (flags & _PAGE_CACHABLE) {
224 		if (flags & _PAGE_WT)
225 			pmb_flags = PMB_WT;
226 		else
227 			pmb_flags = PMB_C;
228 	} else
229 		pmb_flags = PMB_WT | PMB_UB;
230 
231 	pmbp = NULL;
232 	wanted = size;
233 
234 again:
235 	for (i = 0; i < ARRAY_SIZE(pmb_sizes); i++) {
236 		struct pmb_entry *pmbe;
237 		int ret;
238 
239 		if (size < pmb_sizes[i].size)
240 			continue;
241 
242 		pmbe = pmb_alloc(vaddr, phys, pmb_flags | pmb_sizes[i].flag);
243 		if (IS_ERR(pmbe))
244 			return PTR_ERR(pmbe);
245 
246 		ret = set_pmb_entry(pmbe);
247 		if (ret != 0) {
248 			pmb_free(pmbe);
249 			return -EBUSY;
250 		}
251 
252 		phys	+= pmb_sizes[i].size;
253 		vaddr	+= pmb_sizes[i].size;
254 		size	-= pmb_sizes[i].size;
255 
256 		/*
257 		 * Link adjacent entries that span multiple PMB entries
258 		 * for easier tear-down.
259 		 */
260 		if (likely(pmbp))
261 			pmbp->link = pmbe;
262 
263 		pmbp = pmbe;
264 	}
265 
266 	if (size >= 0x1000000)
267 		goto again;
268 
269 	return wanted - size;
270 }
271 
272 void pmb_unmap(unsigned long addr)
273 {
274 	struct pmb_entry **p, *pmbe;
275 
276 	for (p = &pmb_list; (pmbe = *p); p = &pmbe->next)
277 		if (pmbe->vpn == addr)
278 			break;
279 
280 	if (unlikely(!pmbe))
281 		return;
282 
283 	WARN_ON(!test_bit(pmbe->entry, &pmb_map));
284 
285 	do {
286 		struct pmb_entry *pmblink = pmbe;
287 
288 		clear_pmb_entry(pmbe);
289 		pmbe = pmblink->link;
290 
291 		pmb_free(pmblink);
292 	} while (pmbe);
293 }
294 
295 static void pmb_cache_ctor(void *pmb, struct kmem_cache *cachep,
296 			   unsigned long flags)
297 {
298 	struct pmb_entry *pmbe = pmb;
299 
300 	memset(pmb, 0, sizeof(struct pmb_entry));
301 
302 	pmbe->entry = PMB_NO_ENTRY;
303 }
304 
305 static int __init pmb_init(void)
306 {
307 	unsigned int nr_entries = ARRAY_SIZE(pmb_init_map);
308 	unsigned int entry;
309 
310 	BUG_ON(unlikely(nr_entries >= NR_PMB_ENTRIES));
311 
312 	pmb_cache = kmem_cache_create("pmb", sizeof(struct pmb_entry), 0,
313 				      SLAB_PANIC, pmb_cache_ctor, NULL);
314 
315 	jump_to_P2();
316 
317 	/*
318 	 * Ordering is important, P2 must be mapped in the PMB before we
319 	 * can set PMB.SE, and P1 must be mapped before we jump back to
320 	 * P1 space.
321 	 */
322 	for (entry = 0; entry < nr_entries; entry++) {
323 		struct pmb_entry *pmbe = pmb_init_map + entry;
324 
325 		__set_pmb_entry(pmbe->vpn, pmbe->ppn, pmbe->flags, &entry);
326 	}
327 
328 	ctrl_outl(0, PMB_IRMCR);
329 
330 	/* PMB.SE and UB[7] */
331 	ctrl_outl((1 << 31) | (1 << 7), PMB_PASCR);
332 
333 	back_to_P1();
334 
335 	return 0;
336 }
337 arch_initcall(pmb_init);
338 
339 static int pmb_seq_show(struct seq_file *file, void *iter)
340 {
341 	int i;
342 
343 	seq_printf(file, "V: Valid, C: Cacheable, WT: Write-Through\n"
344 			 "CB: Copy-Back, B: Buffered, UB: Unbuffered\n");
345 	seq_printf(file, "ety   vpn  ppn  size   flags\n");
346 
347 	for (i = 0; i < NR_PMB_ENTRIES; i++) {
348 		unsigned long addr, data;
349 		unsigned int size;
350 		char *sz_str = NULL;
351 
352 		addr = ctrl_inl(mk_pmb_addr(i));
353 		data = ctrl_inl(mk_pmb_data(i));
354 
355 		size = data & PMB_SZ_MASK;
356 		sz_str = (size == PMB_SZ_16M)  ? " 16MB":
357 			 (size == PMB_SZ_64M)  ? " 64MB":
358 			 (size == PMB_SZ_128M) ? "128MB":
359 					         "512MB";
360 
361 		/* 02: V 0x88 0x08 128MB C CB  B */
362 		seq_printf(file, "%02d: %c 0x%02lx 0x%02lx %s %c %s %s\n",
363 			   i, ((addr & PMB_V) && (data & PMB_V)) ? 'V' : ' ',
364 			   (addr >> 24) & 0xff, (data >> 24) & 0xff,
365 			   sz_str, (data & PMB_C) ? 'C' : ' ',
366 			   (data & PMB_WT) ? "WT" : "CB",
367 			   (data & PMB_UB) ? "UB" : " B");
368 	}
369 
370 	return 0;
371 }
372 
373 static int pmb_debugfs_open(struct inode *inode, struct file *file)
374 {
375 	return single_open(file, pmb_seq_show, NULL);
376 }
377 
378 static const struct file_operations pmb_debugfs_fops = {
379 	.owner		= THIS_MODULE,
380 	.open		= pmb_debugfs_open,
381 	.read		= seq_read,
382 	.llseek		= seq_lseek,
383 	.release	= seq_release,
384 };
385 
386 static int __init pmb_debugfs_init(void)
387 {
388 	struct dentry *dentry;
389 
390 	dentry = debugfs_create_file("pmb", S_IFREG | S_IRUGO,
391 				     NULL, NULL, &pmb_debugfs_fops);
392 	if (IS_ERR(dentry))
393 		return PTR_ERR(dentry);
394 
395 	return 0;
396 }
397 postcore_initcall(pmb_debugfs_init);
398