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/device.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 <linux/prefetch.h>
24#include <asm/page.h>
25#include <asm/cacheflush.h>
26#include <cpu/sq.h>
27
28struct sq_mapping;
29
30struct sq_mapping {
31	const char *name;
32
33	unsigned long sq_addr;
34	unsigned long addr;
35	unsigned int size;
36
37	struct sq_mapping *next;
38};
39
40static struct sq_mapping *sq_mapping_list;
41static DEFINE_SPINLOCK(sq_mapping_lock);
42static struct kmem_cache *sq_cache;
43static unsigned long *sq_bitmap;
44
45#define store_queue_barrier()			\
46do {						\
47	(void)__raw_readl(P4SEG_STORE_QUE);	\
48	__raw_writel(0, P4SEG_STORE_QUE + 0);	\
49	__raw_writel(0, P4SEG_STORE_QUE + 8);	\
50} while (0);
51
52/**
53 * sq_flush_range - Flush (prefetch) a specific SQ range
54 * @start: the store queue address to start flushing from
55 * @len: the length to flush
56 *
57 * Flushes the store queue cache from @start to @start + @len in a
58 * linear fashion.
59 */
60void sq_flush_range(unsigned long start, unsigned int len)
61{
62	unsigned long *sq = (unsigned long *)start;
63
64	/* Flush the queues */
65	for (len >>= 5; len--; sq += 8)
66		prefetchw(sq);
67
68	/* Wait for completion */
69	store_queue_barrier();
70}
71EXPORT_SYMBOL(sq_flush_range);
72
73static inline void sq_mapping_list_add(struct sq_mapping *map)
74{
75	struct sq_mapping **p, *tmp;
76
77	spin_lock_irq(&sq_mapping_lock);
78
79	p = &sq_mapping_list;
80	while ((tmp = *p) != NULL)
81		p = &tmp->next;
82
83	map->next = tmp;
84	*p = map;
85
86	spin_unlock_irq(&sq_mapping_lock);
87}
88
89static inline void sq_mapping_list_del(struct sq_mapping *map)
90{
91	struct sq_mapping **p, *tmp;
92
93	spin_lock_irq(&sq_mapping_lock);
94
95	for (p = &sq_mapping_list; (tmp = *p); p = &tmp->next)
96		if (tmp == map) {
97			*p = tmp->next;
98			break;
99		}
100
101	spin_unlock_irq(&sq_mapping_lock);
102}
103
104static int __sq_remap(struct sq_mapping *map, pgprot_t prot)
105{
106#if defined(CONFIG_MMU)
107	struct vm_struct *vma;
108
109	vma = __get_vm_area(map->size, VM_ALLOC, map->sq_addr, SQ_ADDRMAX);
110	if (!vma)
111		return -ENOMEM;
112
113	vma->phys_addr = map->addr;
114
115	if (ioremap_page_range((unsigned long)vma->addr,
116			       (unsigned long)vma->addr + map->size,
117			       vma->phys_addr, prot)) {
118		vunmap(vma->addr);
119		return -EAGAIN;
120	}
121#else
122	/*
123	 * Without an MMU (or with it turned off), this is much more
124	 * straightforward, as we can just load up each queue's QACR with
125	 * the physical address appropriately masked.
126	 */
127	__raw_writel(((map->addr >> 26) << 2) & 0x1c, SQ_QACR0);
128	__raw_writel(((map->addr >> 26) << 2) & 0x1c, SQ_QACR1);
129#endif
130
131	return 0;
132}
133
134/**
135 * sq_remap - Map a physical address through the Store Queues
136 * @phys: Physical address of mapping.
137 * @size: Length of mapping.
138 * @name: User invoking mapping.
139 * @prot: Protection bits.
140 *
141 * Remaps the physical address @phys through the next available store queue
142 * address of @size length. @name is logged at boot time as well as through
143 * the sysfs interface.
144 */
145unsigned long sq_remap(unsigned long phys, unsigned int size,
146		       const char *name, pgprot_t prot)
147{
148	struct sq_mapping *map;
149	unsigned long end;
150	unsigned int psz;
151	int ret, page;
152
153	/* Don't allow wraparound or zero size */
154	end = phys + size - 1;
155	if (unlikely(!size || end < phys))
156		return -EINVAL;
157	/* Don't allow anyone to remap normal memory.. */
158	if (unlikely(phys < virt_to_phys(high_memory)))
159		return -EINVAL;
160
161	phys &= PAGE_MASK;
162	size = PAGE_ALIGN(end + 1) - phys;
163
164	map = kmem_cache_alloc(sq_cache, GFP_KERNEL);
165	if (unlikely(!map))
166		return -ENOMEM;
167
168	map->addr = phys;
169	map->size = size;
170	map->name = name;
171
172	page = bitmap_find_free_region(sq_bitmap, 0x04000000 >> PAGE_SHIFT,
173				       get_order(map->size));
174	if (unlikely(page < 0)) {
175		ret = -ENOSPC;
176		goto out;
177	}
178
179	map->sq_addr = P4SEG_STORE_QUE + (page << PAGE_SHIFT);
180
181	ret = __sq_remap(map, prot);
182	if (unlikely(ret != 0))
183		goto out;
184
185	psz = (size + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
186	pr_info("sqremap: %15s  [%4d page%s]  va 0x%08lx   pa 0x%08lx\n",
187		likely(map->name) ? map->name : "???",
188		psz, psz == 1 ? " " : "s",
189		map->sq_addr, map->addr);
190
191	sq_mapping_list_add(map);
192
193	return map->sq_addr;
194
195out:
196	kmem_cache_free(sq_cache, map);
197	return ret;
198}
199EXPORT_SYMBOL(sq_remap);
200
201/**
202 * sq_unmap - Unmap a Store Queue allocation
203 * @vaddr: Pre-allocated Store Queue mapping.
204 *
205 * Unmaps the store queue allocation @map that was previously created by
206 * sq_remap(). Also frees up the pte that was previously inserted into
207 * the kernel page table and discards the UTLB translation.
208 */
209void sq_unmap(unsigned long vaddr)
210{
211	struct sq_mapping **p, *map;
212	int page;
213
214	for (p = &sq_mapping_list; (map = *p); p = &map->next)
215		if (map->sq_addr == vaddr)
216			break;
217
218	if (unlikely(!map)) {
219		printk("%s: bad store queue address 0x%08lx\n",
220		       __func__, vaddr);
221		return;
222	}
223
224	page = (map->sq_addr - P4SEG_STORE_QUE) >> PAGE_SHIFT;
225	bitmap_release_region(sq_bitmap, page, get_order(map->size));
226
227#ifdef CONFIG_MMU
228	{
229		/*
230		 * Tear down the VMA in the MMU case.
231		 */
232		struct vm_struct *vma;
233
234		vma = remove_vm_area((void *)(map->sq_addr & PAGE_MASK));
235		if (!vma) {
236			printk(KERN_ERR "%s: bad address 0x%08lx\n",
237			       __func__, map->sq_addr);
238			return;
239		}
240	}
241#endif
242
243	sq_mapping_list_del(map);
244
245	kmem_cache_free(sq_cache, map);
246}
247EXPORT_SYMBOL(sq_unmap);
248
249/*
250 * Needlessly complex sysfs interface. Unfortunately it doesn't seem like
251 * there is any other easy way to add things on a per-cpu basis without
252 * putting the directory entries somewhere stupid and having to create
253 * links in sysfs by hand back in to the per-cpu directories.
254 *
255 * Some day we may want to have an additional abstraction per store
256 * queue, but considering the kobject hell we already have to deal with,
257 * it's simply not worth the trouble.
258 */
259static struct kobject *sq_kobject[NR_CPUS];
260
261struct sq_sysfs_attr {
262	struct attribute attr;
263	ssize_t (*show)(char *buf);
264	ssize_t (*store)(const char *buf, size_t count);
265};
266
267#define to_sq_sysfs_attr(a)	container_of(a, struct sq_sysfs_attr, attr)
268
269static ssize_t sq_sysfs_show(struct kobject *kobj, struct attribute *attr,
270			     char *buf)
271{
272	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
273
274	if (likely(sattr->show))
275		return sattr->show(buf);
276
277	return -EIO;
278}
279
280static ssize_t sq_sysfs_store(struct kobject *kobj, struct attribute *attr,
281			      const char *buf, size_t count)
282{
283	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
284
285	if (likely(sattr->store))
286		return sattr->store(buf, count);
287
288	return -EIO;
289}
290
291static ssize_t mapping_show(char *buf)
292{
293	struct sq_mapping **list, *entry;
294	char *p = buf;
295
296	for (list = &sq_mapping_list; (entry = *list); list = &entry->next)
297		p += sprintf(p, "%08lx-%08lx [%08lx]: %s\n",
298			     entry->sq_addr, entry->sq_addr + entry->size,
299			     entry->addr, entry->name);
300
301	return p - buf;
302}
303
304static ssize_t mapping_store(const char *buf, size_t count)
305{
306	unsigned long base = 0, len = 0;
307
308	sscanf(buf, "%lx %lx", &base, &len);
309	if (!base)
310		return -EIO;
311
312	if (likely(len)) {
313		int ret = sq_remap(base, len, "Userspace", PAGE_SHARED);
314		if (ret < 0)
315			return ret;
316	} else
317		sq_unmap(base);
318
319	return count;
320}
321
322static struct sq_sysfs_attr mapping_attr =
323	__ATTR(mapping, 0644, mapping_show, mapping_store);
324
325static struct attribute *sq_sysfs_attrs[] = {
326	&mapping_attr.attr,
327	NULL,
328};
329
330static const struct sysfs_ops sq_sysfs_ops = {
331	.show	= sq_sysfs_show,
332	.store	= sq_sysfs_store,
333};
334
335static struct kobj_type ktype_percpu_entry = {
336	.sysfs_ops	= &sq_sysfs_ops,
337	.default_attrs	= sq_sysfs_attrs,
338};
339
340static int sq_dev_add(struct device *dev, struct subsys_interface *sif)
341{
342	unsigned int cpu = dev->id;
343	struct kobject *kobj;
344	int error;
345
346	sq_kobject[cpu] = kzalloc(sizeof(struct kobject), GFP_KERNEL);
347	if (unlikely(!sq_kobject[cpu]))
348		return -ENOMEM;
349
350	kobj = sq_kobject[cpu];
351	error = kobject_init_and_add(kobj, &ktype_percpu_entry, &dev->kobj,
352				     "%s", "sq");
353	if (!error)
354		kobject_uevent(kobj, KOBJ_ADD);
355	return error;
356}
357
358static void sq_dev_remove(struct device *dev, struct subsys_interface *sif)
359{
360	unsigned int cpu = dev->id;
361	struct kobject *kobj = sq_kobject[cpu];
362
363	kobject_put(kobj);
364}
365
366static struct subsys_interface sq_interface = {
367	.name		= "sq",
368	.subsys		= &cpu_subsys,
369	.add_dev	= sq_dev_add,
370	.remove_dev	= sq_dev_remove,
371};
372
373static int __init sq_api_init(void)
374{
375	unsigned int nr_pages = 0x04000000 >> PAGE_SHIFT;
376	unsigned int size = (nr_pages + (BITS_PER_LONG - 1)) / BITS_PER_LONG;
377	int ret = -ENOMEM;
378
379	printk(KERN_NOTICE "sq: Registering store queue API.\n");
380
381	sq_cache = kmem_cache_create("store_queue_cache",
382				sizeof(struct sq_mapping), 0, 0, NULL);
383	if (unlikely(!sq_cache))
384		return ret;
385
386	sq_bitmap = kzalloc(size, GFP_KERNEL);
387	if (unlikely(!sq_bitmap))
388		goto out;
389
390	ret = subsys_interface_register(&sq_interface);
391	if (unlikely(ret != 0))
392		goto out;
393
394	return 0;
395
396out:
397	kfree(sq_bitmap);
398	kmem_cache_destroy(sq_cache);
399
400	return ret;
401}
402
403static void __exit sq_api_exit(void)
404{
405	subsys_interface_unregister(&sq_interface);
406	kfree(sq_bitmap);
407	kmem_cache_destroy(sq_cache);
408}
409
410module_init(sq_api_init);
411module_exit(sq_api_exit);
412
413MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
414MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
415MODULE_LICENSE("GPL");
416