sq.c revision 9f650cf2b811cfb605f10483eeb1dc86f43cdbcb 
1/*
2 * arch/sh/kernel/cpu/sh4/sq.c
3 *
4 * General management API for SH-4 integrated Store Queues
5 *
6 * Copyright (C) 2001 - 2006  Paul Mundt
7 * Copyright (C) 2001, 2002  M. R. Brown
8 *
9 * This file is subject to the terms and conditions of the GNU General Public
10 * License.  See the file "COPYING" in the main directory of this archive
11 * for more details.
12 */
13#include <linux/init.h>
14#include <linux/cpu.h>
15#include <linux/bitmap.h>
16#include <linux/sysdev.h>
17#include <linux/kernel.h>
18#include <linux/module.h>
19#include <linux/slab.h>
20#include <linux/vmalloc.h>
21#include <linux/mm.h>
22#include <linux/io.h>
23#include <asm/page.h>
24#include <asm/cacheflush.h>
25#include <asm/cpu/sq.h>
26
27struct sq_mapping;
28
29struct sq_mapping {
30	const char *name;
31
32	unsigned long sq_addr;
33	unsigned long addr;
34	unsigned int size;
35
36	struct sq_mapping *next;
37};
38
39static struct sq_mapping *sq_mapping_list;
40static DEFINE_SPINLOCK(sq_mapping_lock);
41static kmem_cache_t *sq_cache;
42static unsigned long *sq_bitmap;
43
44#define store_queue_barrier()			\
45do {						\
46	(void)ctrl_inl(P4SEG_STORE_QUE);	\
47	ctrl_outl(0, P4SEG_STORE_QUE + 0);	\
48	ctrl_outl(0, P4SEG_STORE_QUE + 8);	\
49} while (0);
50
51/**
52 * sq_flush_range - Flush (prefetch) a specific SQ range
53 * @start: the store queue address to start flushing from
54 * @len: the length to flush
55 *
56 * Flushes the store queue cache from @start to @start + @len in a
57 * linear fashion.
58 */
59void sq_flush_range(unsigned long start, unsigned int len)
60{
61	volatile unsigned long *sq = (unsigned long *)start;
62
63	/* Flush the queues */
64	for (len >>= 5; len--; sq += 8)
65		prefetchw((void *)sq);
66
67	/* Wait for completion */
68	store_queue_barrier();
69}
70EXPORT_SYMBOL(sq_flush_range);
71
72static inline void sq_mapping_list_add(struct sq_mapping *map)
73{
74	struct sq_mapping **p, *tmp;
75
76	spin_lock_irq(&sq_mapping_lock);
77
78	p = &sq_mapping_list;
79	while ((tmp = *p) != NULL)
80		p = &tmp->next;
81
82	map->next = tmp;
83	*p = map;
84
85	spin_unlock_irq(&sq_mapping_lock);
86}
87
88static inline void sq_mapping_list_del(struct sq_mapping *map)
89{
90	struct sq_mapping **p, *tmp;
91
92	spin_lock_irq(&sq_mapping_lock);
93
94	for (p = &sq_mapping_list; (tmp = *p); p = &tmp->next)
95		if (tmp == map) {
96			*p = tmp->next;
97			break;
98		}
99
100	spin_unlock_irq(&sq_mapping_lock);
101}
102
103static int __sq_remap(struct sq_mapping *map, unsigned long flags)
104{
105#if defined(CONFIG_MMU)
106	struct vm_struct *vma;
107
108	vma = __get_vm_area(map->size, VM_ALLOC, map->sq_addr, SQ_ADDRMAX);
109	if (!vma)
110		return -ENOMEM;
111
112	vma->phys_addr = map->addr;
113
114	if (remap_area_pages((unsigned long)vma->addr, vma->phys_addr,
115			     map->size, flags)) {
116		vunmap(vma->addr);
117		return -EAGAIN;
118	}
119#else
120	/*
121	 * Without an MMU (or with it turned off), this is much more
122	 * straightforward, as we can just load up each queue's QACR with
123	 * the physical address appropriately masked.
124	 */
125	ctrl_outl(((map->addr >> 26) << 2) & 0x1c, SQ_QACR0);
126	ctrl_outl(((map->addr >> 26) << 2) & 0x1c, SQ_QACR1);
127#endif
128
129	return 0;
130}
131
132/**
133 * sq_remap - Map a physical address through the Store Queues
134 * @phys: Physical address of mapping.
135 * @size: Length of mapping.
136 * @name: User invoking mapping.
137 * @flags: Protection flags.
138 *
139 * Remaps the physical address @phys through the next available store queue
140 * address of @size length. @name is logged at boot time as well as through
141 * the sysfs interface.
142 */
143unsigned long sq_remap(unsigned long phys, unsigned int size,
144		       const char *name, unsigned long flags)
145{
146	struct sq_mapping *map;
147	unsigned long end;
148	unsigned int psz;
149	int ret, page;
150
151	/* Don't allow wraparound or zero size */
152	end = phys + size - 1;
153	if (unlikely(!size || end < phys))
154		return -EINVAL;
155	/* Don't allow anyone to remap normal memory.. */
156	if (unlikely(phys < virt_to_phys(high_memory)))
157		return -EINVAL;
158
159	phys &= PAGE_MASK;
160	size = PAGE_ALIGN(end + 1) - phys;
161
162	map = kmem_cache_alloc(sq_cache, GFP_KERNEL);
163	if (unlikely(!map))
164		return -ENOMEM;
165
166	map->addr = phys;
167	map->size = size;
168	map->name = name;
169
170	page = bitmap_find_free_region(sq_bitmap, 0x04000000 >> PAGE_SHIFT,
171				       get_order(map->size));
172	if (unlikely(page < 0)) {
173		ret = -ENOSPC;
174		goto out;
175	}
176
177	map->sq_addr = P4SEG_STORE_QUE + (page << PAGE_SHIFT);
178
179	ret = __sq_remap(map, flags);
180	if (unlikely(ret != 0))
181		goto out;
182
183	psz = (size + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
184	pr_info("sqremap: %15s  [%4d page%s]  va 0x%08lx   pa 0x%08lx\n",
185		likely(map->name) ? map->name : "???",
186		psz, psz == 1 ? " " : "s",
187		map->sq_addr, map->addr);
188
189	sq_mapping_list_add(map);
190
191	return map->sq_addr;
192
193out:
194	kmem_cache_free(sq_cache, map);
195	return ret;
196}
197EXPORT_SYMBOL(sq_remap);
198
199/**
200 * sq_unmap - Unmap a Store Queue allocation
201 * @map: Pre-allocated Store Queue mapping.
202 *
203 * Unmaps the store queue allocation @map that was previously created by
204 * sq_remap(). Also frees up the pte that was previously inserted into
205 * the kernel page table and discards the UTLB translation.
206 */
207void sq_unmap(unsigned long vaddr)
208{
209	struct sq_mapping **p, *map;
210	struct vm_struct *vma;
211	int page;
212
213	for (p = &sq_mapping_list; (map = *p); p = &map->next)
214		if (map->sq_addr == vaddr)
215			break;
216
217	if (unlikely(!map)) {
218		printk("%s: bad store queue address 0x%08lx\n",
219		       __FUNCTION__, vaddr);
220		return;
221	}
222
223	page = (map->sq_addr - P4SEG_STORE_QUE) >> PAGE_SHIFT;
224	bitmap_release_region(sq_bitmap, page, get_order(map->size));
225
226#ifdef CONFIG_MMU
227	vma = remove_vm_area((void *)(map->sq_addr & PAGE_MASK));
228	if (!vma) {
229		printk(KERN_ERR "%s: bad address 0x%08lx\n",
230		       __FUNCTION__, map->sq_addr);
231		return;
232	}
233#endif
234
235	sq_mapping_list_del(map);
236
237	kmem_cache_free(sq_cache, map);
238}
239EXPORT_SYMBOL(sq_unmap);
240
241/*
242 * Needlessly complex sysfs interface. Unfortunately it doesn't seem like
243 * there is any other easy way to add things on a per-cpu basis without
244 * putting the directory entries somewhere stupid and having to create
245 * links in sysfs by hand back in to the per-cpu directories.
246 *
247 * Some day we may want to have an additional abstraction per store
248 * queue, but considering the kobject hell we already have to deal with,
249 * it's simply not worth the trouble.
250 */
251static struct kobject *sq_kobject[NR_CPUS];
252
253struct sq_sysfs_attr {
254	struct attribute attr;
255	ssize_t (*show)(char *buf);
256	ssize_t (*store)(const char *buf, size_t count);
257};
258
259#define to_sq_sysfs_attr(attr)	container_of(attr, struct sq_sysfs_attr, attr)
260
261static ssize_t sq_sysfs_show(struct kobject *kobj, struct attribute *attr,
262			     char *buf)
263{
264	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
265
266	if (likely(sattr->show))
267		return sattr->show(buf);
268
269	return -EIO;
270}
271
272static ssize_t sq_sysfs_store(struct kobject *kobj, struct attribute *attr,
273			      const char *buf, size_t count)
274{
275	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
276
277	if (likely(sattr->store))
278		return sattr->store(buf, count);
279
280	return -EIO;
281}
282
283static ssize_t mapping_show(char *buf)
284{
285	struct sq_mapping **list, *entry;
286	char *p = buf;
287
288	for (list = &sq_mapping_list; (entry = *list); list = &entry->next)
289		p += sprintf(p, "%08lx-%08lx [%08lx]: %s\n",
290			     entry->sq_addr, entry->sq_addr + entry->size,
291			     entry->addr, entry->name);
292
293	return p - buf;
294}
295
296static ssize_t mapping_store(const char *buf, size_t count)
297{
298	unsigned long base = 0, len = 0;
299
300	sscanf(buf, "%lx %lx", &base, &len);
301	if (!base)
302		return -EIO;
303
304	if (likely(len)) {
305		int ret = sq_remap(base, len, "Userspace",
306				   pgprot_val(PAGE_SHARED));
307		if (ret < 0)
308			return ret;
309	} else
310		sq_unmap(base);
311
312	return count;
313}
314
315static struct sq_sysfs_attr mapping_attr =
316	__ATTR(mapping, 0644, mapping_show, mapping_store);
317
318static struct attribute *sq_sysfs_attrs[] = {
319	&mapping_attr.attr,
320	NULL,
321};
322
323static struct sysfs_ops sq_sysfs_ops = {
324	.show	= sq_sysfs_show,
325	.store	= sq_sysfs_store,
326};
327
328static struct kobj_type ktype_percpu_entry = {
329	.sysfs_ops	= &sq_sysfs_ops,
330	.default_attrs	= sq_sysfs_attrs,
331};
332
333static int __devinit sq_sysdev_add(struct sys_device *sysdev)
334{
335	unsigned int cpu = sysdev->id;
336	struct kobject *kobj;
337
338	sq_kobject[cpu] = kzalloc(sizeof(struct kobject), GFP_KERNEL);
339	if (unlikely(!sq_kobject[cpu]))
340		return -ENOMEM;
341
342	kobj = sq_kobject[cpu];
343	kobj->parent = &sysdev->kobj;
344	kobject_set_name(kobj, "%s", "sq");
345	kobj->ktype = &ktype_percpu_entry;
346
347	return kobject_register(kobj);
348}
349
350static int __devexit sq_sysdev_remove(struct sys_device *sysdev)
351{
352	unsigned int cpu = sysdev->id;
353	struct kobject *kobj = sq_kobject[cpu];
354
355	kobject_unregister(kobj);
356	return 0;
357}
358
359static struct sysdev_driver sq_sysdev_driver = {
360	.add		= sq_sysdev_add,
361	.remove		= __devexit_p(sq_sysdev_remove),
362};
363
364static int __init sq_api_init(void)
365{
366	unsigned int nr_pages = 0x04000000 >> PAGE_SHIFT;
367	unsigned int size = (nr_pages + (BITS_PER_LONG - 1)) / BITS_PER_LONG;
368	int ret = -ENOMEM;
369
370	printk(KERN_NOTICE "sq: Registering store queue API.\n");
371
372	sq_cache = kmem_cache_create("store_queue_cache",
373				sizeof(struct sq_mapping), 0, 0,
374				NULL, NULL);
375	if (unlikely(!sq_cache))
376		return ret;
377
378	sq_bitmap = kzalloc(size, GFP_KERNEL);
379	if (unlikely(!sq_bitmap))
380		goto out;
381
382	ret = sysdev_driver_register(&cpu_sysdev_class, &sq_sysdev_driver);
383	if (unlikely(ret != 0))
384		goto out;
385
386	return 0;
387
388out:
389	kfree(sq_bitmap);
390	kmem_cache_destroy(sq_cache);
391
392	return ret;
393}
394
395static void __exit sq_api_exit(void)
396{
397	sysdev_driver_unregister(&cpu_sysdev_class, &sq_sysdev_driver);
398	kfree(sq_bitmap);
399	kmem_cache_destroy(sq_cache);
400}
401
402module_init(sq_api_init);
403module_exit(sq_api_exit);
404
405MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
406MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
407MODULE_LICENSE("GPL");
408