aboutsummaryrefslogtreecommitdiff
path: root/arch/sh/kernel/cpu/sh4/sq.c
blob: 83a4f91bce5aefab58cfdbd06e6c27f438ac2161 (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
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
/*
 * arch/sh/kernel/cpu/sq.c
 *
 * General management API for SH-4 integrated Store Queues
 *
 * Copyright (C) 2001, 2002, 2003, 2004  Paul Mundt
 * Copyright (C) 2001, 2002  M. R. Brown
 *
 * Some of this code has been adopted directly from the old arch/sh/mm/sq.c
 * hack that was part of the LinuxDC project. For all intents and purposes,
 * this is a completely new interface that really doesn't have much in common
 * with the old zone-based approach at all. In fact, it's only listed here for
 * general completeness.
 *
 * 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/module.h>
#include <linux/config.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/proc_fs.h>
#include <linux/miscdevice.h>
#include <linux/vmalloc.h>

#include <asm/io.h>
#include <asm/page.h>
#include <asm/mmu_context.h>
#include <asm/cpu/sq.h>

static LIST_HEAD(sq_mapping_list);
static DEFINE_SPINLOCK(sq_mapping_lock);

/**
 * sq_flush - Flush (prefetch) the store queue cache
 * @addr: the store queue address to flush
 *
 * Executes a prefetch instruction on the specified store queue cache,
 * so that the cached data is written to physical memory.
 */
inline void sq_flush(void *addr)
{
	__asm__ __volatile__ ("pref @%0" : : "r" (addr) : "memory");
}

/**
 * sq_flush_range - Flush (prefetch) a specific SQ range
 * @start: the store queue address to start flushing from
 * @len: the length to flush
 *
 * Flushes the store queue cache from @start to @start + @len in a
 * linear fashion.
 */
void sq_flush_range(unsigned long start, unsigned int len)
{
	volatile unsigned long *sq = (unsigned long *)start;
	unsigned long dummy;

	/* Flush the queues */
	for (len >>= 5; len--; sq += 8)
		sq_flush((void *)sq);

	/* Wait for completion */
	dummy = ctrl_inl(P4SEG_STORE_QUE);

	ctrl_outl(0, P4SEG_STORE_QUE + 0);
	ctrl_outl(0, P4SEG_STORE_QUE + 8);
}

static struct sq_mapping *__sq_alloc_mapping(unsigned long virt, unsigned long phys, unsigned long size, const char *name)
{
	struct sq_mapping *map;

	if (virt + size > SQ_ADDRMAX)
		return ERR_PTR(-ENOSPC);

	map = kmalloc(sizeof(struct sq_mapping), GFP_KERNEL);
	if (!map)
		return ERR_PTR(-ENOMEM);

	INIT_LIST_HEAD(&map->list);

	map->sq_addr	= virt;
	map->addr	= phys;
	map->size	= size + 1;
	map->name	= name;

	list_add(&map->list, &sq_mapping_list);

	return map;
}

static unsigned long __sq_get_next_addr(void)
{
	if (!list_empty(&sq_mapping_list)) {
		struct list_head *pos, *tmp;

		/*
		 * Read one off the list head, as it will have the highest
		 * mapped allocation. Set the next one up right above it.
		 *
		 * This is somewhat sub-optimal, as we don't look at
		 * gaps between allocations or anything lower then the
		 * highest-level allocation.
		 *
		 * However, in the interest of performance and the general
		 * lack of desire to do constant list rebalancing, we don't
		 * worry about it.
		 */
		list_for_each_safe(pos, tmp, &sq_mapping_list) {
			struct sq_mapping *entry;

			entry = list_entry(pos, typeof(*entry), list);

			return entry->sq_addr + entry->size;
		}
	}

	return P4SEG_STORE_QUE;
}

/**
 * __sq_remap - Perform a translation from the SQ to a phys addr
 * @map: sq mapping containing phys and store queue addresses.
 *
 * Maps the store queue address specified in the mapping to the physical
 * address specified in the mapping.
 */
static struct sq_mapping *__sq_remap(struct sq_mapping *map)
{
	unsigned long flags, pteh, ptel;
	struct vm_struct *vma;
	pgprot_t pgprot;

	/*
	 * Without an MMU (or with it turned off), this is much more
	 * straightforward, as we can just load up each queue's QACR with
	 * the physical address appropriately masked.
	 */

	ctrl_outl(((map->addr >> 26) << 2) & 0x1c, SQ_QACR0);
	ctrl_outl(((map->addr >> 26) << 2) & 0x1c, SQ_QACR1);

#ifdef CONFIG_MMU
	/*
	 * With an MMU on the other hand, things are slightly more involved.
	 * Namely, we have to have a direct mapping between the SQ addr and
	 * the associated physical address in the UTLB by way of setting up
	 * a virt<->phys translation by hand. We do this by simply specifying
	 * the SQ addr in UTLB.VPN and the associated physical address in
	 * UTLB.PPN.
	 *
	 * Notably, even though this is a special case translation, and some
	 * of the configuration bits are meaningless, we're still required
	 * to have a valid ASID context in PTEH.
	 *
	 * We could also probably get by without explicitly setting PTEA, but
	 * we do it here just for good measure.
	 */
	spin_lock_irqsave(&sq_mapping_lock, flags);

	pteh = map->sq_addr;
	ctrl_outl((pteh & MMU_VPN_MASK) | get_asid(), MMU_PTEH);

	ptel = map->addr & PAGE_MASK;
	ctrl_outl(((ptel >> 28) & 0xe) | (ptel & 0x1), MMU_PTEA);

	pgprot = pgprot_noncached(PAGE_KERNEL);

	ptel &= _PAGE_FLAGS_HARDWARE_MASK;
	ptel |= pgprot_val(pgprot);
	ctrl_outl(ptel, MMU_PTEL);

	__asm__ __volatile__ ("ldtlb" : : : "memory");

	spin_unlock_irqrestore(&sq_mapping_lock, flags);

	/*
	 * Next, we need to map ourselves in the kernel page table, so that
	 * future accesses after a TLB flush will be handled when we take a
	 * page fault.
	 *
	 * Theoretically we could just do this directly and not worry about
	 * setting up the translation by hand ahead of time, but for the
	 * cases where we want a one-shot SQ mapping followed by a quick
	 * writeout before we hit the TLB flush, we do it anyways. This way
	 * we at least save ourselves the initial page fault overhead.
	 */
	vma = __get_vm_area(map->size, VM_ALLOC, map->sq_addr, SQ_ADDRMAX);
	if (!vma)
		return ERR_PTR(-ENOMEM);

	vma->phys_addr = map->addr;

	if (remap_area_pages((unsigned long)vma->addr, vma->phys_addr,
			     map->size, pgprot_val(pgprot))) {
		vunmap(vma->addr);
		return NULL;
	}
#endif /* CONFIG_MMU */

	return map;
}

/**
 * sq_remap - Map a physical address through the Store Queues
 * @phys: Physical address of mapping.
 * @size: Length of mapping.
 * @name: User invoking mapping.
 *
 * Remaps the physical address @phys through the next available store queue
 * address of @size length. @name is logged at boot time as well as through
 * the procfs interface.
 *
 * A pre-allocated and filled sq_mapping pointer is returned, and must be
 * cleaned up with a call to sq_unmap() when the user is done with the
 * mapping.
 */
struct sq_mapping *sq_remap(unsigned long phys, unsigned int size, const char *name)
{
	struct sq_mapping *map;
	unsigned long virt, end;
	unsigned int psz;

	/* Don't allow wraparound or zero size */
	end = phys + size - 1;
	if (!size || end < phys)
		return NULL;
	/* Don't allow anyone to remap normal memory.. */
	if (phys < virt_to_phys(high_memory))
		return NULL;

	phys &= PAGE_MASK;

	size  = PAGE_ALIGN(end + 1) - phys;
	virt  = __sq_get_next_addr();
	psz   = (size + (PAGE_SIZE - 1)) / PAGE_SIZE;
	map   = __sq_alloc_mapping(virt, phys, size, name);

	printk("sqremap: %15s  [%4d page%s]  va 0x%08lx   pa 0x%08lx\n",
	       map->name ? map->name : "???",
	       psz, psz == 1 ? " " : "s",
	       map->sq_addr, map->addr);

	return __sq_remap(map);
}

/**
 * sq_unmap - Unmap a Store Queue allocation
 * @map: Pre-allocated Store Queue mapping.
 *
 * Unmaps the store queue allocation @map that was previously created by
 * sq_remap(). Also frees up the pte that was previously inserted into
 * the kernel page table and discards the UTLB translation.
 */
void sq_unmap(struct sq_mapping *map)
{
	if (map->sq_addr > (unsigned long)high_memory)
		vfree((void *)(map->sq_addr & PAGE_MASK));

	list_del(&map->list);
	kfree(map);
}

/**
 * sq_clear - Clear a store queue range
 * @addr: Address to start clearing from.
 * @len: Length to clear.
 *
 * A quick zero-fill implementation for clearing out memory that has been
 * remapped through the store queues.
 */
void sq_clear(unsigned long addr, unsigned int len)
{
	int i;

	/* Clear out both queues linearly */
	for (i = 0; i < 8; i++) {
		ctrl_outl(0, addr + i + 0);
		ctrl_outl(0, addr + i + 8);
	}

	sq_flush_range(addr, len);
}

/**
 * sq_vma_unmap - Unmap a VMA range
 * @area: VMA containing range.
 * @addr: Start of range.
 * @len: Length of range.
 *
 * Searches the sq_mapping_list for a mapping matching the sq addr @addr,
 * and subsequently frees up the entry. Further cleanup is done by generic
 * code.
 */
static void sq_vma_unmap(struct vm_area_struct *area,
			 unsigned long addr, size_t len)
{
	struct list_head *pos, *tmp;

	list_for_each_safe(pos, tmp, &sq_mapping_list) {
		struct sq_mapping *entry;

		entry = list_entry(pos, typeof(*entry), list);

		if (entry->sq_addr == addr) {
			/*
			 * We could probably get away without doing the tlb flush
			 * here, as generic code should take care of most of this
			 * when unmapping the rest of the VMA range for us. Leave
			 * it in for added sanity for the time being..
			 */
			__flush_tlb_page(get_asid(), entry->sq_addr & PAGE_MASK);

			list_del(&entry->list);
			kfree(entry);

			return;
		}
	}
}

/**
 * sq_vma_sync - Sync a VMA range
 * @area: VMA containing range.
 * @start: Start of range.
 * @len: Length of range.
 * @flags: Additional flags.
 *
 * Synchronizes an sq mapped range by flushing the store queue cache for
 * the duration of the mapping.
 *
 * Used internally for user mappings, which must use msync() to prefetch
 * the store queue cache.
 */
static int sq_vma_sync(struct vm_area_struct *area,
		       unsigned long start, size_t len, unsigned int flags)
{
	sq_flush_range(start, len);

	return 0;
}

static struct vm_operations_struct sq_vma_ops = {
	.unmap	= sq_vma_unmap,
	.sync	= sq_vma_sync,
};

/**
 * sq_mmap - mmap() for /dev/cpu/sq
 * @file: unused.
 * @vma: VMA to remap.
 *
 * Remap the specified vma @vma through the store queues, and setup associated
 * information for the new mapping. Also build up the page tables for the new
 * area.
 */
static int sq_mmap(struct file *file, struct vm_area_struct *vma)
{
	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
	unsigned long size = vma->vm_end - vma->vm_start;
	struct sq_mapping *map;

	/*
	 * We're not interested in any arbitrary virtual address that has
	 * been stuck in the VMA, as we already know what addresses we
	 * want. Save off the size, and reposition the VMA to begin at
	 * the next available sq address.
	 */
	vma->vm_start = __sq_get_next_addr();
	vma->vm_end   = vma->vm_start + size;

	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	vma->vm_flags |= VM_IO | VM_RESERVED;

	map = __sq_alloc_mapping(vma->vm_start, offset, size, "Userspace");

	if (io_remap_pfn_range(vma, map->sq_addr, map->addr >> PAGE_SHIFT,
				size, vma->vm_page_prot))
		return -EAGAIN;

	vma->vm_ops = &sq_vma_ops;

	return 0;
}

#ifdef CONFIG_PROC_FS
static int sq_mapping_read_proc(char *buf, char **start, off_t off,
				int len, int *eof, void *data)
{
	struct list_head *pos;
	char *p = buf;

	list_for_each_prev(pos, &sq_mapping_list) {
		struct sq_mapping *entry;

		entry = list_entry(pos, typeof(*entry), list);

		p += sprintf(p, "%08lx-%08lx [%08lx]: %s\n", entry->sq_addr,
			     entry->sq_addr + entry->size - 1, entry->addr,
			     entry->name);
	}

	return p - buf;
}
#endif

static struct file_operations sq_fops = {
	.owner		= THIS_MODULE,
	.mmap		= sq_mmap,
};

static struct miscdevice sq_dev = {
	.minor		= STORE_QUEUE_MINOR,
	.name		= "sq",
	.fops		= &sq_fops,
};

static int __init sq_api_init(void)
{
	printk(KERN_NOTICE "sq: Registering store queue API.\n");

#ifdef CONFIG_PROC_FS
	create_proc_read_entry("sq_mapping", 0, 0, sq_mapping_read_proc, 0);
#endif

	return misc_register(&sq_dev);
}

static void __exit sq_api_exit(void)
{
	misc_deregister(&sq_dev);
}

module_init(sq_api_init);
module_exit(sq_api_exit);

MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(STORE_QUEUE_MINOR);

EXPORT_SYMBOL(sq_remap);
EXPORT_SYMBOL(sq_unmap);
EXPORT_SYMBOL(sq_clear);
EXPORT_SYMBOL(sq_flush);
EXPORT_SYMBOL(sq_flush_range);