xref: /openbmc/linux/arch/parisc/kernel/pci-dma.c (revision 54725958)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 ** PARISC 1.1 Dynamic DMA mapping support.
4 ** This implementation is for PA-RISC platforms that do not support
5 ** I/O TLBs (aka DMA address translation hardware).
6 ** See Documentation/core-api/dma-api-howto.rst for interface definitions.
7 **
8 **      (c) Copyright 1999,2000 Hewlett-Packard Company
9 **      (c) Copyright 2000 Grant Grundler
10 **	(c) Copyright 2000 Philipp Rumpf <prumpf@tux.org>
11 **      (c) Copyright 2000 John Marvin
12 **
13 ** "leveraged" from 2.3.47: arch/ia64/kernel/pci-dma.c.
14 ** (I assume it's from David Mosberger-Tang but there was no Copyright)
15 **
16 ** AFAIK, all PA7100LC and PA7300LC platforms can use this code.
17 **
18 ** - ggg
19 */
20 
21 #include <linux/init.h>
22 #include <linux/gfp.h>
23 #include <linux/mm.h>
24 #include <linux/proc_fs.h>
25 #include <linux/seq_file.h>
26 #include <linux/string.h>
27 #include <linux/types.h>
28 #include <linux/dma-direct.h>
29 #include <linux/dma-map-ops.h>
30 
31 #include <asm/cacheflush.h>
32 #include <asm/dma.h>    /* for DMA_CHUNK_SIZE */
33 #include <asm/io.h>
34 #include <asm/page.h>	/* get_order */
35 #include <linux/uaccess.h>
36 #include <asm/tlbflush.h>	/* for purge_tlb_*() macros */
37 
38 static struct proc_dir_entry * proc_gsc_root __read_mostly = NULL;
39 static unsigned long pcxl_used_bytes __read_mostly;
40 static unsigned long pcxl_used_pages __read_mostly;
41 
42 unsigned long pcxl_dma_start __ro_after_init; /* pcxl dma mapping area start */
43 static DEFINE_SPINLOCK(pcxl_res_lock);
44 static char    *pcxl_res_map;
45 static int     pcxl_res_hint;
46 static int     pcxl_res_size;
47 
48 #ifdef DEBUG_PCXL_RESOURCE
49 #define DBG_RES(x...)	printk(x)
50 #else
51 #define DBG_RES(x...)
52 #endif
53 
54 
55 /*
56 ** Dump a hex representation of the resource map.
57 */
58 
59 #ifdef DUMP_RESMAP
60 static
dump_resmap(void)61 void dump_resmap(void)
62 {
63 	u_long *res_ptr = (unsigned long *)pcxl_res_map;
64 	u_long i = 0;
65 
66 	printk("res_map: ");
67 	for(; i < (pcxl_res_size / sizeof(unsigned long)); ++i, ++res_ptr)
68 		printk("%08lx ", *res_ptr);
69 
70 	printk("\n");
71 }
72 #else
dump_resmap(void)73 static inline void dump_resmap(void) {;}
74 #endif
75 
map_pte_uncached(pte_t * pte,unsigned long vaddr,unsigned long size,unsigned long * paddr_ptr)76 static inline int map_pte_uncached(pte_t * pte,
77 		unsigned long vaddr,
78 		unsigned long size, unsigned long *paddr_ptr)
79 {
80 	unsigned long end;
81 	unsigned long orig_vaddr = vaddr;
82 
83 	vaddr &= ~PMD_MASK;
84 	end = vaddr + size;
85 	if (end > PMD_SIZE)
86 		end = PMD_SIZE;
87 	do {
88 		unsigned long flags;
89 
90 		if (!pte_none(*pte))
91 			printk(KERN_ERR "map_pte_uncached: page already exists\n");
92 		purge_tlb_start(flags);
93 		set_pte(pte, __mk_pte(*paddr_ptr, PAGE_KERNEL_UNC));
94 		pdtlb(SR_KERNEL, orig_vaddr);
95 		purge_tlb_end(flags);
96 		vaddr += PAGE_SIZE;
97 		orig_vaddr += PAGE_SIZE;
98 		(*paddr_ptr) += PAGE_SIZE;
99 		pte++;
100 	} while (vaddr < end);
101 	return 0;
102 }
103 
map_pmd_uncached(pmd_t * pmd,unsigned long vaddr,unsigned long size,unsigned long * paddr_ptr)104 static inline int map_pmd_uncached(pmd_t * pmd, unsigned long vaddr,
105 		unsigned long size, unsigned long *paddr_ptr)
106 {
107 	unsigned long end;
108 	unsigned long orig_vaddr = vaddr;
109 
110 	vaddr &= ~PGDIR_MASK;
111 	end = vaddr + size;
112 	if (end > PGDIR_SIZE)
113 		end = PGDIR_SIZE;
114 	do {
115 		pte_t * pte = pte_alloc_kernel(pmd, vaddr);
116 		if (!pte)
117 			return -ENOMEM;
118 		if (map_pte_uncached(pte, orig_vaddr, end - vaddr, paddr_ptr))
119 			return -ENOMEM;
120 		vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
121 		orig_vaddr += PMD_SIZE;
122 		pmd++;
123 	} while (vaddr < end);
124 	return 0;
125 }
126 
map_uncached_pages(unsigned long vaddr,unsigned long size,unsigned long paddr)127 static inline int map_uncached_pages(unsigned long vaddr, unsigned long size,
128 		unsigned long paddr)
129 {
130 	pgd_t * dir;
131 	unsigned long end = vaddr + size;
132 
133 	dir = pgd_offset_k(vaddr);
134 	do {
135 		p4d_t *p4d;
136 		pud_t *pud;
137 		pmd_t *pmd;
138 
139 		p4d = p4d_offset(dir, vaddr);
140 		pud = pud_offset(p4d, vaddr);
141 		pmd = pmd_alloc(NULL, pud, vaddr);
142 
143 		if (!pmd)
144 			return -ENOMEM;
145 		if (map_pmd_uncached(pmd, vaddr, end - vaddr, &paddr))
146 			return -ENOMEM;
147 		vaddr = vaddr + PGDIR_SIZE;
148 		dir++;
149 	} while (vaddr && (vaddr < end));
150 	return 0;
151 }
152 
unmap_uncached_pte(pmd_t * pmd,unsigned long vaddr,unsigned long size)153 static inline void unmap_uncached_pte(pmd_t * pmd, unsigned long vaddr,
154 		unsigned long size)
155 {
156 	pte_t * pte;
157 	unsigned long end;
158 	unsigned long orig_vaddr = vaddr;
159 
160 	if (pmd_none(*pmd))
161 		return;
162 	if (pmd_bad(*pmd)) {
163 		pmd_ERROR(*pmd);
164 		pmd_clear(pmd);
165 		return;
166 	}
167 	pte = pte_offset_kernel(pmd, vaddr);
168 	vaddr &= ~PMD_MASK;
169 	end = vaddr + size;
170 	if (end > PMD_SIZE)
171 		end = PMD_SIZE;
172 	do {
173 		unsigned long flags;
174 		pte_t page = *pte;
175 
176 		pte_clear(&init_mm, vaddr, pte);
177 		purge_tlb_start(flags);
178 		pdtlb(SR_KERNEL, orig_vaddr);
179 		purge_tlb_end(flags);
180 		vaddr += PAGE_SIZE;
181 		orig_vaddr += PAGE_SIZE;
182 		pte++;
183 		if (pte_none(page) || pte_present(page))
184 			continue;
185 		printk(KERN_CRIT "Whee.. Swapped out page in kernel page table\n");
186 	} while (vaddr < end);
187 }
188 
unmap_uncached_pmd(pgd_t * dir,unsigned long vaddr,unsigned long size)189 static inline void unmap_uncached_pmd(pgd_t * dir, unsigned long vaddr,
190 		unsigned long size)
191 {
192 	pmd_t * pmd;
193 	unsigned long end;
194 	unsigned long orig_vaddr = vaddr;
195 
196 	if (pgd_none(*dir))
197 		return;
198 	if (pgd_bad(*dir)) {
199 		pgd_ERROR(*dir);
200 		pgd_clear(dir);
201 		return;
202 	}
203 	pmd = pmd_offset(pud_offset(p4d_offset(dir, vaddr), vaddr), vaddr);
204 	vaddr &= ~PGDIR_MASK;
205 	end = vaddr + size;
206 	if (end > PGDIR_SIZE)
207 		end = PGDIR_SIZE;
208 	do {
209 		unmap_uncached_pte(pmd, orig_vaddr, end - vaddr);
210 		vaddr = (vaddr + PMD_SIZE) & PMD_MASK;
211 		orig_vaddr += PMD_SIZE;
212 		pmd++;
213 	} while (vaddr < end);
214 }
215 
unmap_uncached_pages(unsigned long vaddr,unsigned long size)216 static void unmap_uncached_pages(unsigned long vaddr, unsigned long size)
217 {
218 	pgd_t * dir;
219 	unsigned long end = vaddr + size;
220 
221 	dir = pgd_offset_k(vaddr);
222 	do {
223 		unmap_uncached_pmd(dir, vaddr, end - vaddr);
224 		vaddr = vaddr + PGDIR_SIZE;
225 		dir++;
226 	} while (vaddr && (vaddr < end));
227 }
228 
229 #define PCXL_SEARCH_LOOP(idx, mask, size)  \
230        for(; res_ptr < res_end; ++res_ptr) \
231        { \
232                if(0 == ((*res_ptr) & mask)) { \
233                        *res_ptr |= mask; \
234 		       idx = (int)((u_long)res_ptr - (u_long)pcxl_res_map); \
235 		       pcxl_res_hint = idx + (size >> 3); \
236                        goto resource_found; \
237                } \
238        }
239 
240 #define PCXL_FIND_FREE_MAPPING(idx, mask, size)  { \
241        u##size *res_ptr = (u##size *)&(pcxl_res_map[pcxl_res_hint & ~((size >> 3) - 1)]); \
242        u##size *res_end = (u##size *)&pcxl_res_map[pcxl_res_size]; \
243        PCXL_SEARCH_LOOP(idx, mask, size); \
244        res_ptr = (u##size *)&pcxl_res_map[0]; \
245        PCXL_SEARCH_LOOP(idx, mask, size); \
246 }
247 
248 static unsigned long
pcxl_alloc_range(size_t size)249 pcxl_alloc_range(size_t size)
250 {
251 	int res_idx;
252 	u_long mask, flags;
253 	unsigned int pages_needed = size >> PAGE_SHIFT;
254 
255 	mask = (u_long) -1L;
256  	mask >>= BITS_PER_LONG - pages_needed;
257 
258 	DBG_RES("pcxl_alloc_range() size: %d pages_needed %d pages_mask 0x%08lx\n",
259 		size, pages_needed, mask);
260 
261 	spin_lock_irqsave(&pcxl_res_lock, flags);
262 
263 	if(pages_needed <= 8) {
264 		PCXL_FIND_FREE_MAPPING(res_idx, mask, 8);
265 	} else if(pages_needed <= 16) {
266 		PCXL_FIND_FREE_MAPPING(res_idx, mask, 16);
267 	} else if(pages_needed <= 32) {
268 		PCXL_FIND_FREE_MAPPING(res_idx, mask, 32);
269 	} else {
270 		panic("%s: pcxl_alloc_range() Too many pages to map.\n",
271 		      __FILE__);
272 	}
273 
274 	dump_resmap();
275 	panic("%s: pcxl_alloc_range() out of dma mapping resources\n",
276 	      __FILE__);
277 
278 resource_found:
279 
280 	DBG_RES("pcxl_alloc_range() res_idx %d mask 0x%08lx res_hint: %d\n",
281 		res_idx, mask, pcxl_res_hint);
282 
283 	pcxl_used_pages += pages_needed;
284 	pcxl_used_bytes += ((pages_needed >> 3) ? (pages_needed >> 3) : 1);
285 
286 	spin_unlock_irqrestore(&pcxl_res_lock, flags);
287 
288 	dump_resmap();
289 
290 	/*
291 	** return the corresponding vaddr in the pcxl dma map
292 	*/
293 	return (pcxl_dma_start + (res_idx << (PAGE_SHIFT + 3)));
294 }
295 
296 #define PCXL_FREE_MAPPINGS(idx, m, size) \
297 		u##size *res_ptr = (u##size *)&(pcxl_res_map[(idx) + (((size >> 3) - 1) & (~((size >> 3) - 1)))]); \
298 		/* BUG_ON((*res_ptr & m) != m); */ \
299 		*res_ptr &= ~m;
300 
301 /*
302 ** clear bits in the pcxl resource map
303 */
304 static void
pcxl_free_range(unsigned long vaddr,size_t size)305 pcxl_free_range(unsigned long vaddr, size_t size)
306 {
307 	u_long mask, flags;
308 	unsigned int res_idx = (vaddr - pcxl_dma_start) >> (PAGE_SHIFT + 3);
309 	unsigned int pages_mapped = size >> PAGE_SHIFT;
310 
311 	mask = (u_long) -1L;
312  	mask >>= BITS_PER_LONG - pages_mapped;
313 
314 	DBG_RES("pcxl_free_range() res_idx: %d size: %d pages_mapped %d mask 0x%08lx\n",
315 		res_idx, size, pages_mapped, mask);
316 
317 	spin_lock_irqsave(&pcxl_res_lock, flags);
318 
319 	if(pages_mapped <= 8) {
320 		PCXL_FREE_MAPPINGS(res_idx, mask, 8);
321 	} else if(pages_mapped <= 16) {
322 		PCXL_FREE_MAPPINGS(res_idx, mask, 16);
323 	} else if(pages_mapped <= 32) {
324 		PCXL_FREE_MAPPINGS(res_idx, mask, 32);
325 	} else {
326 		panic("%s: pcxl_free_range() Too many pages to unmap.\n",
327 		      __FILE__);
328 	}
329 
330 	pcxl_used_pages -= (pages_mapped ? pages_mapped : 1);
331 	pcxl_used_bytes -= ((pages_mapped >> 3) ? (pages_mapped >> 3) : 1);
332 
333 	spin_unlock_irqrestore(&pcxl_res_lock, flags);
334 
335 	dump_resmap();
336 }
337 
proc_pcxl_dma_show(struct seq_file * m,void * v)338 static int __maybe_unused proc_pcxl_dma_show(struct seq_file *m, void *v)
339 {
340 #if 0
341 	u_long i = 0;
342 	unsigned long *res_ptr = (u_long *)pcxl_res_map;
343 #endif
344 	unsigned long total_pages = pcxl_res_size << 3;   /* 8 bits per byte */
345 
346 	seq_printf(m, "\nDMA Mapping Area size    : %d bytes (%ld pages)\n",
347 		PCXL_DMA_MAP_SIZE, total_pages);
348 
349 	seq_printf(m, "Resource bitmap : %d bytes\n", pcxl_res_size);
350 
351 	seq_puts(m,  "     	  total:    free:    used:   % used:\n");
352 	seq_printf(m, "blocks  %8d %8ld %8ld %8ld%%\n", pcxl_res_size,
353 		pcxl_res_size - pcxl_used_bytes, pcxl_used_bytes,
354 		(pcxl_used_bytes * 100) / pcxl_res_size);
355 
356 	seq_printf(m, "pages   %8ld %8ld %8ld %8ld%%\n", total_pages,
357 		total_pages - pcxl_used_pages, pcxl_used_pages,
358 		(pcxl_used_pages * 100 / total_pages));
359 
360 #if 0
361 	seq_puts(m, "\nResource bitmap:");
362 
363 	for(; i < (pcxl_res_size / sizeof(u_long)); ++i, ++res_ptr) {
364 		if ((i & 7) == 0)
365 		    seq_puts(m,"\n   ");
366 		seq_printf(m, "%s %08lx", buf, *res_ptr);
367 	}
368 #endif
369 	seq_putc(m, '\n');
370 	return 0;
371 }
372 
373 static int __init
pcxl_dma_init(void)374 pcxl_dma_init(void)
375 {
376 	if (pcxl_dma_start == 0)
377 		return 0;
378 
379 	pcxl_res_size = PCXL_DMA_MAP_SIZE >> (PAGE_SHIFT + 3);
380 	pcxl_res_hint = 0;
381 	pcxl_res_map = (char *)__get_free_pages(GFP_KERNEL,
382 					    get_order(pcxl_res_size));
383 	memset(pcxl_res_map, 0, pcxl_res_size);
384 	proc_gsc_root = proc_mkdir("bus/gsc", NULL);
385 	if (!proc_gsc_root)
386     		printk(KERN_WARNING
387 			"pcxl_dma_init: Unable to create gsc /proc dir entry\n");
388 	else {
389 		struct proc_dir_entry* ent;
390 		ent = proc_create_single("pcxl_dma", 0, proc_gsc_root,
391 				proc_pcxl_dma_show);
392 		if (!ent)
393 			printk(KERN_WARNING
394 				"pci-dma.c: Unable to create pcxl_dma /proc entry.\n");
395 	}
396 	return 0;
397 }
398 
399 __initcall(pcxl_dma_init);
400 
arch_dma_alloc(struct device * dev,size_t size,dma_addr_t * dma_handle,gfp_t gfp,unsigned long attrs)401 void *arch_dma_alloc(struct device *dev, size_t size,
402 		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
403 {
404 	unsigned long vaddr;
405 	unsigned long paddr;
406 	int order;
407 
408 	if (boot_cpu_data.cpu_type != pcxl2 && boot_cpu_data.cpu_type != pcxl)
409 		return NULL;
410 
411 	order = get_order(size);
412 	size = 1 << (order + PAGE_SHIFT);
413 	vaddr = pcxl_alloc_range(size);
414 	paddr = __get_free_pages(gfp | __GFP_ZERO, order);
415 	flush_kernel_dcache_range(paddr, size);
416 	paddr = __pa(paddr);
417 	map_uncached_pages(vaddr, size, paddr);
418 	*dma_handle = (dma_addr_t) paddr;
419 
420 	return (void *)vaddr;
421 }
422 
arch_dma_free(struct device * dev,size_t size,void * vaddr,dma_addr_t dma_handle,unsigned long attrs)423 void arch_dma_free(struct device *dev, size_t size, void *vaddr,
424 		dma_addr_t dma_handle, unsigned long attrs)
425 {
426 	int order = get_order(size);
427 
428 	WARN_ON_ONCE(boot_cpu_data.cpu_type != pcxl2 &&
429 		     boot_cpu_data.cpu_type != pcxl);
430 
431 	size = 1 << (order + PAGE_SHIFT);
432 	unmap_uncached_pages((unsigned long)vaddr, size);
433 	pcxl_free_range((unsigned long)vaddr, size);
434 
435 	free_pages((unsigned long)__va(dma_handle), order);
436 }
437 
arch_sync_dma_for_device(phys_addr_t paddr,size_t size,enum dma_data_direction dir)438 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
439 		enum dma_data_direction dir)
440 {
441 	/*
442 	 * fdc: The data cache line is written back to memory, if and only if
443 	 * it is dirty, and then invalidated from the data cache.
444 	 */
445 	flush_kernel_dcache_range((unsigned long)phys_to_virt(paddr), size);
446 }
447 
arch_sync_dma_for_cpu(phys_addr_t paddr,size_t size,enum dma_data_direction dir)448 void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
449 		enum dma_data_direction dir)
450 {
451 	unsigned long addr = (unsigned long) phys_to_virt(paddr);
452 
453 	switch (dir) {
454 	case DMA_TO_DEVICE:
455 	case DMA_BIDIRECTIONAL:
456 		flush_kernel_dcache_range(addr, size);
457 		return;
458 	case DMA_FROM_DEVICE:
459 		purge_kernel_dcache_range_asm(addr, addr + size);
460 		return;
461 	default:
462 		BUG();
463 	}
464 }
465