xref: /openbmc/linux/arch/sh/kernel/cpu/sh4/sq.c (revision c8ec3743) 
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 
25 struct sq_mapping;
26 
27 struct 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 
37 static struct sq_mapping *sq_mapping_list;
38 static DEFINE_SPINLOCK(sq_mapping_lock);
39 static struct kmem_cache *sq_cache;
40 static unsigned long *sq_bitmap;
41 
42 #define store_queue_barrier()			\
43 do {						\
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  */
57 void 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 }
68 EXPORT_SYMBOL(sq_flush_range);
69 
70 static 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 
86 static 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 
101 static 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(map->size, VM_ALLOC, map->sq_addr, SQ_ADDRMAX);
107 	if (!vma)
108 		return -ENOMEM;
109 
110 	vma->phys_addr = map->addr;
111 
112 	if (ioremap_page_range((unsigned long)vma->addr,
113 			       (unsigned long)vma->addr + map->size,
114 			       vma->phys_addr, prot)) {
115 		vunmap(vma->addr);
116 		return -EAGAIN;
117 	}
118 #else
119 	/*
120 	 * Without an MMU (or with it turned off), this is much more
121 	 * straightforward, as we can just load up each queue's QACR with
122 	 * the physical address appropriately masked.
123 	 */
124 	__raw_writel(((map->addr >> 26) << 2) & 0x1c, SQ_QACR0);
125 	__raw_writel(((map->addr >> 26) << 2) & 0x1c, SQ_QACR1);
126 #endif
127 
128 	return 0;
129 }
130 
131 /**
132  * sq_remap - Map a physical address through the Store Queues
133  * @phys: Physical address of mapping.
134  * @size: Length of mapping.
135  * @name: User invoking mapping.
136  * @prot: Protection bits.
137  *
138  * Remaps the physical address @phys through the next available store queue
139  * address of @size length. @name is logged at boot time as well as through
140  * the sysfs interface.
141  */
142 unsigned long sq_remap(unsigned long phys, unsigned int size,
143 		       const char *name, pgprot_t prot)
144 {
145 	struct sq_mapping *map;
146 	unsigned long end;
147 	unsigned int psz;
148 	int ret, page;
149 
150 	/* Don't allow wraparound or zero size */
151 	end = phys + size - 1;
152 	if (unlikely(!size || end < phys))
153 		return -EINVAL;
154 	/* Don't allow anyone to remap normal memory.. */
155 	if (unlikely(phys < virt_to_phys(high_memory)))
156 		return -EINVAL;
157 
158 	phys &= PAGE_MASK;
159 	size = PAGE_ALIGN(end + 1) - phys;
160 
161 	map = kmem_cache_alloc(sq_cache, GFP_KERNEL);
162 	if (unlikely(!map))
163 		return -ENOMEM;
164 
165 	map->addr = phys;
166 	map->size = size;
167 	map->name = name;
168 
169 	page = bitmap_find_free_region(sq_bitmap, 0x04000000 >> PAGE_SHIFT,
170 				       get_order(map->size));
171 	if (unlikely(page < 0)) {
172 		ret = -ENOSPC;
173 		goto out;
174 	}
175 
176 	map->sq_addr = P4SEG_STORE_QUE + (page << PAGE_SHIFT);
177 
178 	ret = __sq_remap(map, prot);
179 	if (unlikely(ret != 0))
180 		goto out;
181 
182 	psz = (size + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
183 	pr_info("sqremap: %15s  [%4d page%s]  va 0x%08lx   pa 0x%08lx\n",
184 		likely(map->name) ? map->name : "???",
185 		psz, psz == 1 ? " " : "s",
186 		map->sq_addr, map->addr);
187 
188 	sq_mapping_list_add(map);
189 
190 	return map->sq_addr;
191 
192 out:
193 	kmem_cache_free(sq_cache, map);
194 	return ret;
195 }
196 EXPORT_SYMBOL(sq_remap);
197 
198 /**
199  * sq_unmap - Unmap a Store Queue allocation
200  * @vaddr: Pre-allocated Store Queue mapping.
201  *
202  * Unmaps the store queue allocation @map that was previously created by
203  * sq_remap(). Also frees up the pte that was previously inserted into
204  * the kernel page table and discards the UTLB translation.
205  */
206 void sq_unmap(unsigned long vaddr)
207 {
208 	struct sq_mapping **p, *map;
209 	int page;
210 
211 	for (p = &sq_mapping_list; (map = *p); p = &map->next)
212 		if (map->sq_addr == vaddr)
213 			break;
214 
215 	if (unlikely(!map)) {
216 		printk("%s: bad store queue address 0x%08lx\n",
217 		       __func__, vaddr);
218 		return;
219 	}
220 
221 	page = (map->sq_addr - P4SEG_STORE_QUE) >> PAGE_SHIFT;
222 	bitmap_release_region(sq_bitmap, page, get_order(map->size));
223 
224 #ifdef CONFIG_MMU
225 	{
226 		/*
227 		 * Tear down the VMA in the MMU case.
228 		 */
229 		struct vm_struct *vma;
230 
231 		vma = remove_vm_area((void *)(map->sq_addr & PAGE_MASK));
232 		if (!vma) {
233 			printk(KERN_ERR "%s: bad address 0x%08lx\n",
234 			       __func__, map->sq_addr);
235 			return;
236 		}
237 	}
238 #endif
239 
240 	sq_mapping_list_del(map);
241 
242 	kmem_cache_free(sq_cache, map);
243 }
244 EXPORT_SYMBOL(sq_unmap);
245 
246 /*
247  * Needlessly complex sysfs interface. Unfortunately it doesn't seem like
248  * there is any other easy way to add things on a per-cpu basis without
249  * putting the directory entries somewhere stupid and having to create
250  * links in sysfs by hand back in to the per-cpu directories.
251  *
252  * Some day we may want to have an additional abstraction per store
253  * queue, but considering the kobject hell we already have to deal with,
254  * it's simply not worth the trouble.
255  */
256 static struct kobject *sq_kobject[NR_CPUS];
257 
258 struct sq_sysfs_attr {
259 	struct attribute attr;
260 	ssize_t (*show)(char *buf);
261 	ssize_t (*store)(const char *buf, size_t count);
262 };
263 
264 #define to_sq_sysfs_attr(a)	container_of(a, struct sq_sysfs_attr, attr)
265 
266 static ssize_t sq_sysfs_show(struct kobject *kobj, struct attribute *attr,
267 			     char *buf)
268 {
269 	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
270 
271 	if (likely(sattr->show))
272 		return sattr->show(buf);
273 
274 	return -EIO;
275 }
276 
277 static ssize_t sq_sysfs_store(struct kobject *kobj, struct attribute *attr,
278 			      const char *buf, size_t count)
279 {
280 	struct sq_sysfs_attr *sattr = to_sq_sysfs_attr(attr);
281 
282 	if (likely(sattr->store))
283 		return sattr->store(buf, count);
284 
285 	return -EIO;
286 }
287 
288 static ssize_t mapping_show(char *buf)
289 {
290 	struct sq_mapping **list, *entry;
291 	char *p = buf;
292 
293 	for (list = &sq_mapping_list; (entry = *list); list = &entry->next)
294 		p += sprintf(p, "%08lx-%08lx [%08lx]: %s\n",
295 			     entry->sq_addr, entry->sq_addr + entry->size,
296 			     entry->addr, entry->name);
297 
298 	return p - buf;
299 }
300 
301 static ssize_t mapping_store(const char *buf, size_t count)
302 {
303 	unsigned long base = 0, len = 0;
304 
305 	sscanf(buf, "%lx %lx", &base, &len);
306 	if (!base)
307 		return -EIO;
308 
309 	if (likely(len)) {
310 		int ret = sq_remap(base, len, "Userspace", PAGE_SHARED);
311 		if (ret < 0)
312 			return ret;
313 	} else
314 		sq_unmap(base);
315 
316 	return count;
317 }
318 
319 static struct sq_sysfs_attr mapping_attr =
320 	__ATTR(mapping, 0644, mapping_show, mapping_store);
321 
322 static struct attribute *sq_sysfs_attrs[] = {
323 	&mapping_attr.attr,
324 	NULL,
325 };
326 
327 static const struct sysfs_ops sq_sysfs_ops = {
328 	.show	= sq_sysfs_show,
329 	.store	= sq_sysfs_store,
330 };
331 
332 static struct kobj_type ktype_percpu_entry = {
333 	.sysfs_ops	= &sq_sysfs_ops,
334 	.default_attrs	= sq_sysfs_attrs,
335 };
336 
337 static int sq_dev_add(struct device *dev, struct subsys_interface *sif)
338 {
339 	unsigned int cpu = dev->id;
340 	struct kobject *kobj;
341 	int error;
342 
343 	sq_kobject[cpu] = kzalloc(sizeof(struct kobject), GFP_KERNEL);
344 	if (unlikely(!sq_kobject[cpu]))
345 		return -ENOMEM;
346 
347 	kobj = sq_kobject[cpu];
348 	error = kobject_init_and_add(kobj, &ktype_percpu_entry, &dev->kobj,
349 				     "%s", "sq");
350 	if (!error)
351 		kobject_uevent(kobj, KOBJ_ADD);
352 	return error;
353 }
354 
355 static void sq_dev_remove(struct device *dev, struct subsys_interface *sif)
356 {
357 	unsigned int cpu = dev->id;
358 	struct kobject *kobj = sq_kobject[cpu];
359 
360 	kobject_put(kobj);
361 }
362 
363 static struct subsys_interface sq_interface = {
364 	.name		= "sq",
365 	.subsys		= &cpu_subsys,
366 	.add_dev	= sq_dev_add,
367 	.remove_dev	= sq_dev_remove,
368 };
369 
370 static int __init sq_api_init(void)
371 {
372 	unsigned int nr_pages = 0x04000000 >> PAGE_SHIFT;
373 	unsigned int size = (nr_pages + (BITS_PER_LONG - 1)) / BITS_PER_LONG;
374 	int ret = -ENOMEM;
375 
376 	printk(KERN_NOTICE "sq: Registering store queue API.\n");
377 
378 	sq_cache = kmem_cache_create("store_queue_cache",
379 				sizeof(struct sq_mapping), 0, 0, NULL);
380 	if (unlikely(!sq_cache))
381 		return ret;
382 
383 	sq_bitmap = kzalloc(size, GFP_KERNEL);
384 	if (unlikely(!sq_bitmap))
385 		goto out;
386 
387 	ret = subsys_interface_register(&sq_interface);
388 	if (unlikely(ret != 0))
389 		goto out;
390 
391 	return 0;
392 
393 out:
394 	kfree(sq_bitmap);
395 	kmem_cache_destroy(sq_cache);
396 
397 	return ret;
398 }
399 
400 static void __exit sq_api_exit(void)
401 {
402 	subsys_interface_unregister(&sq_interface);
403 	kfree(sq_bitmap);
404 	kmem_cache_destroy(sq_cache);
405 }
406 
407 module_init(sq_api_init);
408 module_exit(sq_api_exit);
409 
410 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
411 MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
412 MODULE_LICENSE("GPL");
413