xref: /openbmc/linux/arch/sh/kernel/cpu/sh4/sq.c (revision 3a83e4e6) 
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_caller(map->size, VM_ALLOC, 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  */
143 unsigned 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 
193 out:
194 	kmem_cache_free(sq_cache, map);
195 	return ret;
196 }
197 EXPORT_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  */
207 void 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 }
245 EXPORT_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  */
257 static struct kobject *sq_kobject[NR_CPUS];
258 
259 struct 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 
267 static 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 
278 static 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 
289 static 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 
302 static 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 
320 static struct sq_sysfs_attr mapping_attr =
321 	__ATTR(mapping, 0644, mapping_show, mapping_store);
322 
323 static struct attribute *sq_sysfs_attrs[] = {
324 	&mapping_attr.attr,
325 	NULL,
326 };
327 
328 static const struct sysfs_ops sq_sysfs_ops = {
329 	.show	= sq_sysfs_show,
330 	.store	= sq_sysfs_store,
331 };
332 
333 static struct kobj_type ktype_percpu_entry = {
334 	.sysfs_ops	= &sq_sysfs_ops,
335 	.default_attrs	= sq_sysfs_attrs,
336 };
337 
338 static int sq_dev_add(struct device *dev, struct subsys_interface *sif)
339 {
340 	unsigned int cpu = dev->id;
341 	struct kobject *kobj;
342 	int error;
343 
344 	sq_kobject[cpu] = kzalloc(sizeof(struct kobject), GFP_KERNEL);
345 	if (unlikely(!sq_kobject[cpu]))
346 		return -ENOMEM;
347 
348 	kobj = sq_kobject[cpu];
349 	error = kobject_init_and_add(kobj, &ktype_percpu_entry, &dev->kobj,
350 				     "%s", "sq");
351 	if (!error)
352 		kobject_uevent(kobj, KOBJ_ADD);
353 	return error;
354 }
355 
356 static void sq_dev_remove(struct device *dev, struct subsys_interface *sif)
357 {
358 	unsigned int cpu = dev->id;
359 	struct kobject *kobj = sq_kobject[cpu];
360 
361 	kobject_put(kobj);
362 }
363 
364 static struct subsys_interface sq_interface = {
365 	.name		= "sq",
366 	.subsys		= &cpu_subsys,
367 	.add_dev	= sq_dev_add,
368 	.remove_dev	= sq_dev_remove,
369 };
370 
371 static int __init sq_api_init(void)
372 {
373 	unsigned int nr_pages = 0x04000000 >> PAGE_SHIFT;
374 	unsigned int size = (nr_pages + (BITS_PER_LONG - 1)) / BITS_PER_LONG;
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 = kzalloc(size, 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 
394 out:
395 	kfree(sq_bitmap);
396 	kmem_cache_destroy(sq_cache);
397 
398 	return ret;
399 }
400 
401 static void __exit sq_api_exit(void)
402 {
403 	subsys_interface_unregister(&sq_interface);
404 	kfree(sq_bitmap);
405 	kmem_cache_destroy(sq_cache);
406 }
407 
408 module_init(sq_api_init);
409 module_exit(sq_api_exit);
410 
411 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>, M. R. Brown <mrbrown@0xd6.org>");
412 MODULE_DESCRIPTION("Simple API for SH-4 integrated Store Queues");
413 MODULE_LICENSE("GPL");
414