1// SPDX-License-Identifier: GPL-2.0
2/*
3 * arch/sh/kernel/cpu/sh4/sq.c
4 *
5 * General management API for SH-4 integrated Store Queues
6 *
7 * Copyright (C) 2001 - 2006  Paul Mundt
8 * Copyright (C) 2001, 2002  M. R. Brown
9 */
10#include <linux/init.h>
11#include <linux/cpu.h>
12#include <linux/bitmap.h>
13#include <linux/device.h>
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/vmalloc.h>
18#include <linux/mm.h>
19#include <linux/io.h>
20#include <linux/prefetch.h>
21#include <asm/page.h>
22#include <asm/cacheflush.h>
23#include <cpu/sq.h>
24
25struct sq_mapping;
26
27struct sq_mapping {
28	const char *name;
29
30	unsigned long sq_addr;
31	unsigned long addr;
32	unsigned int size;
33
34	struct sq_mapping *next;
35};
36
37static struct sq_mapping *sq_mapping_list;
38static DEFINE_SPINLOCK(sq_mapping_lock);
39static struct kmem_cache *sq_cache;
40static unsigned long *sq_bitmap;
41
42#define store_queue_barrier()			\
43do {						\
44	(void)__raw_readl(P4SEG_STORE_QUE);	\
45	__raw_writel(0, P4SEG_STORE_QUE + 0);	\
46	__raw_writel(0, P4SEG_STORE_QUE + 8);	\
47} while (0);
48
49/**
50 * sq_flush_range - Flush (prefetch) a specific SQ range
51 * @start: the store queue address to start flushing from
52 * @len: the length to flush
53 *
54 * Flushes the store queue cache from @start to @start + @len in a
55 * linear fashion.
56 */
57void sq_flush_range(unsigned long start, unsigned int len)
58{
59	unsigned long *sq = (unsigned long *)start;
60
61	/* Flush the queues */
62	for (len >>= 5; len--; sq += 8)
63		prefetchw(sq);
64
65	/* Wait for completion */
66	store_queue_barrier();
67}
68EXPORT_SYMBOL(sq_flush_range);
69
70static inline void sq_mapping_list_add(struct sq_mapping *map)
71{
72	struct sq_mapping **p, *tmp;
73
74	spin_lock_irq(&sq_mapping_lock);
75
76	p = &sq_mapping_list;
77	while ((tmp = *p) != NULL)
78		p = &tmp->next;
79
80	map->next = tmp;
81	*p = map;
82
83	spin_unlock_irq(&sq_mapping_lock);
84}
85
86static inline void sq_mapping_list_del(struct sq_mapping *map)
87{
88	struct sq_mapping **p, *tmp;
89
90	spin_lock_irq(&sq_mapping_lock);
91
92	for (p = &sq_mapping_list; (tmp = *p); p = &tmp->next)
93		if (tmp == map) {
94			*p = tmp->next;
95			break;
96		}
97
98	spin_unlock_irq(&sq_mapping_lock);
99}
100
101static int __sq_remap(struct sq_mapping *map, pgprot_t prot)
102{
103#if defined(CONFIG_MMU)
104	struct vm_struct *vma;
105
106	vma = __get_vm_area_caller(map->size, VM_IOREMAP, map->sq_addr,
107			SQ_ADDRMAX, __builtin_return_address(0));
108	if (!vma)
109		return -ENOMEM;
110
111	vma->phys_addr = map->addr;
112
113	if (ioremap_page_range((unsigned long)vma->addr,
114			       (unsigned long)vma->addr + map->size,
115			       vma->phys_addr, prot)) {
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	__raw_writel(((map->addr >> 26) << 2) & 0x1c, SQ_QACR0);
126	__raw_writel(((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 * @prot: Protection bits.
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, pgprot_t prot)
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, prot);
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 * @vaddr: 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	int page;
211
212	for (p = &sq_mapping_list; (map = *p); p = &map->next)
213		if (map->sq_addr == vaddr)
214			break;
215
216	if (unlikely(!map)) {
217		printk("%s: bad store queue address 0x%08lx\n",
218		       __func__, vaddr);
219		return;
220	}
221
222	page = (map->sq_addr - P4SEG_STORE_QUE) >> PAGE_SHIFT;
223	bitmap_release_region(sq_bitmap, page, get_order(map->size));
224
225#ifdef CONFIG_MMU
226	{
227		/*
228		 * Tear down the VMA in the MMU case.
229		 */
230		struct vm_struct *vma;
231
232		vma = remove_vm_area((void *)(map->sq_addr & PAGE_MASK));
233		if (!vma) {
234			printk(KERN_ERR "%s: bad address 0x%08lx\n",
235			       __func__, map->sq_addr);
236			return;
237		}
238	}
239#endif
240
241	sq_mapping_list_del(map);
242
243	kmem_cache_free(sq_cache, map);
244}
245EXPORT_SYMBOL(sq_unmap);
246
247/*
248 * Needlessly complex sysfs interface. Unfortunately it doesn't seem like
249 * there is any other easy way to add things on a per-cpu basis without
250 * putting the directory entries somewhere stupid and having to create
251 * links in sysfs by hand back in to the per-cpu directories.
252 *
253 * Some day we may want to have an additional abstraction per store
254 * queue, but considering the kobject hell we already have to deal with,
255 * it's simply not worth the trouble.
256 */
257static struct kobject *sq_kobject[NR_CPUS];
258
259struct sq_sysfs_attr {
260	struct attribute attr;
261	ssize_t (*show)(char *buf);
262	ssize_t (*store)(const char *buf, size_t count);
263};
264
265#define to_sq_sysfs_attr(a)	container_of(a, struct sq_sysfs_attr, attr)
266
267static ssize_t sq_sysfs_show(struct kobject *kobj, struct attribute *attr,
268			     char *buf)
269{
270	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
271
272	if (likely(sattr->show))
273		return sattr->show(buf);
274
275	return -EIO;
276}
277
278static ssize_t sq_sysfs_store(struct kobject *kobj, struct attribute *attr,
279			      const char *buf, size_t count)
280{
281	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
282
283	if (likely(sattr->store))
284		return sattr->store(buf, count);
285
286	return -EIO;
287}
288
289static ssize_t mapping_show(char *buf)
290{
291	struct sq_mapping **list, *entry;
292	char *p = buf;
293
294	for (list = &sq_mapping_list; (entry = *list); list = &entry->next)
295		p += sprintf(p, "%08lx-%08lx [%08lx]: %s\n",
296			     entry->sq_addr, entry->sq_addr + entry->size,
297			     entry->addr, entry->name);
298
299	return p - buf;
300}
301
302static ssize_t mapping_store(const char *buf, size_t count)
303{
304	unsigned long base = 0, len = 0;
305
306	sscanf(buf, "%lx %lx", &base, &len);
307	if (!base)
308		return -EIO;
309
310	if (likely(len)) {
311		int ret = sq_remap(base, len, "Userspace", PAGE_SHARED);
312		if (ret < 0)
313			return ret;
314	} else
315		sq_unmap(base);
316
317	return count;
318}
319
320static struct sq_sysfs_attr mapping_attr =
321	__ATTR(mapping, 0644, mapping_show, mapping_store);
322
323static struct attribute *sq_sysfs_attrs[] = {
324	&mapping_attr.attr,
325	NULL,
326};
327ATTRIBUTE_GROUPS(sq_sysfs);
328
329static const struct sysfs_ops sq_sysfs_ops = {
330	.show	= sq_sysfs_show,
331	.store	= sq_sysfs_store,
332};
333
334static struct kobj_type ktype_percpu_entry = {
335	.sysfs_ops	= &sq_sysfs_ops,
336	.default_groups	= sq_sysfs_groups,
337};
338
339static int sq_dev_add(struct device *dev, struct subsys_interface *sif)
340{
341	unsigned int cpu = dev->id;
342	struct kobject *kobj;
343	int error;
344
345	sq_kobject[cpu] = kzalloc(sizeof(struct kobject), GFP_KERNEL);
346	if (unlikely(!sq_kobject[cpu]))
347		return -ENOMEM;
348
349	kobj = sq_kobject[cpu];
350	error = kobject_init_and_add(kobj, &ktype_percpu_entry, &dev->kobj,
351				     "%s", "sq");
352	if (!error)
353		kobject_uevent(kobj, KOBJ_ADD);
354	return error;
355}
356
357static void sq_dev_remove(struct device *dev, struct subsys_interface *sif)
358{
359	unsigned int cpu = dev->id;
360	struct kobject *kobj = sq_kobject[cpu];
361
362	kobject_put(kobj);
363}
364
365static struct subsys_interface sq_interface = {
366	.name		= "sq",
367	.subsys		= &cpu_subsys,
368	.add_dev	= sq_dev_add,
369	.remove_dev	= sq_dev_remove,
370};
371
372static int __init sq_api_init(void)
373{
374	unsigned int nr_pages = 0x04000000 >> PAGE_SHIFT;
375	int ret = -ENOMEM;
376
377	printk(KERN_NOTICE "sq: Registering store queue API.\n");
378
379	sq_cache = kmem_cache_create("store_queue_cache",
380				sizeof(struct sq_mapping), 0, 0, NULL);
381	if (unlikely(!sq_cache))
382		return ret;
383
384	sq_bitmap = bitmap_zalloc(nr_pages, GFP_KERNEL);
385	if (unlikely(!sq_bitmap))
386		goto out;
387
388	ret = subsys_interface_register(&sq_interface);
389	if (unlikely(ret != 0))
390		goto out;
391
392	return 0;
393
394out:
395	bitmap_free(sq_bitmap);
396	kmem_cache_destroy(sq_cache);
397
398	return ret;
399}
400
401static void __exit sq_api_exit(void)
402{
403	subsys_interface_unregister(&sq_interface);
404	bitmap_free(sq_bitmap);
405	kmem_cache_destroy(sq_cache);
406}
407
408module_init(sq_api_init);
409module_exit(sq_api_exit);
410
411MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
412MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
413MODULE_LICENSE("GPL");
414