Linux 3.16-rc2
[linux/fpc-iii.git] / arch / microblaze / mm / consistent.c
blobe10ad930895e23a5d8e229ba3267eb9344dc772e
1 /*
2 * Microblaze support for cache consistent memory.
3 * Copyright (C) 2010 Michal Simek <monstr@monstr.eu>
4 * Copyright (C) 2010 PetaLogix
5 * Copyright (C) 2005 John Williams <jwilliams@itee.uq.edu.au>
7 * Based on PowerPC version derived from arch/arm/mm/consistent.c
8 * Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
9 * Copyright (C) 2000 Russell King
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
16 #include <linux/export.h>
17 #include <linux/signal.h>
18 #include <linux/sched.h>
19 #include <linux/kernel.h>
20 #include <linux/errno.h>
21 #include <linux/string.h>
22 #include <linux/types.h>
23 #include <linux/ptrace.h>
24 #include <linux/mman.h>
25 #include <linux/mm.h>
26 #include <linux/swap.h>
27 #include <linux/stddef.h>
28 #include <linux/vmalloc.h>
29 #include <linux/init.h>
30 #include <linux/delay.h>
31 #include <linux/bootmem.h>
32 #include <linux/highmem.h>
33 #include <linux/pci.h>
34 #include <linux/interrupt.h>
35 #include <linux/gfp.h>
37 #include <asm/pgalloc.h>
38 #include <linux/io.h>
39 #include <linux/hardirq.h>
40 #include <linux/mmu_context.h>
41 #include <asm/mmu.h>
42 #include <linux/uaccess.h>
43 #include <asm/pgtable.h>
44 #include <asm/cpuinfo.h>
45 #include <asm/tlbflush.h>
47 #ifndef CONFIG_MMU
48 /* I have to use dcache values because I can't relate on ram size */
49 # define UNCACHED_SHADOW_MASK (cpuinfo.dcache_high - cpuinfo.dcache_base + 1)
50 #endif
53 * Consistent memory allocators. Used for DMA devices that want to
54 * share uncached memory with the processor core.
55 * My crufty no-MMU approach is simple. In the HW platform we can optionally
56 * mirror the DDR up above the processor cacheable region. So, memory accessed
57 * in this mirror region will not be cached. It's alloced from the same
58 * pool as normal memory, but the handle we return is shifted up into the
59 * uncached region. This will no doubt cause big problems if memory allocated
60 * here is not also freed properly. -- JW
62 void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
64 unsigned long order, vaddr;
65 void *ret;
66 unsigned int i, err = 0;
67 struct page *page, *end;
69 #ifdef CONFIG_MMU
70 phys_addr_t pa;
71 struct vm_struct *area;
72 unsigned long va;
73 #endif
75 if (in_interrupt())
76 BUG();
78 /* Only allocate page size areas. */
79 size = PAGE_ALIGN(size);
80 order = get_order(size);
82 vaddr = __get_free_pages(gfp, order);
83 if (!vaddr)
84 return NULL;
87 * we need to ensure that there are no cachelines in use,
88 * or worse dirty in this area.
90 flush_dcache_range(virt_to_phys((void *)vaddr),
91 virt_to_phys((void *)vaddr) + size);
93 #ifndef CONFIG_MMU
94 ret = (void *)vaddr;
96 * Here's the magic! Note if the uncached shadow is not implemented,
97 * it's up to the calling code to also test that condition and make
98 * other arranegments, such as manually flushing the cache and so on.
100 # ifdef CONFIG_XILINX_UNCACHED_SHADOW
101 ret = (void *)((unsigned) ret | UNCACHED_SHADOW_MASK);
102 # endif
103 if ((unsigned int)ret > cpuinfo.dcache_base &&
104 (unsigned int)ret < cpuinfo.dcache_high)
105 pr_warn("ERROR: Your cache coherent area is CACHED!!!\n");
107 /* dma_handle is same as physical (shadowed) address */
108 *dma_handle = (dma_addr_t)ret;
109 #else
110 /* Allocate some common virtual space to map the new pages. */
111 area = get_vm_area(size, VM_ALLOC);
112 if (!area) {
113 free_pages(vaddr, order);
114 return NULL;
116 va = (unsigned long) area->addr;
117 ret = (void *)va;
119 /* This gives us the real physical address of the first page. */
120 *dma_handle = pa = __virt_to_phys(vaddr);
121 #endif
124 * free wasted pages. We skip the first page since we know
125 * that it will have count = 1 and won't require freeing.
126 * We also mark the pages in use as reserved so that
127 * remap_page_range works.
129 page = virt_to_page(vaddr);
130 end = page + (1 << order);
132 split_page(page, order);
134 for (i = 0; i < size && err == 0; i += PAGE_SIZE) {
135 #ifdef CONFIG_MMU
136 /* MS: This is the whole magic - use cache inhibit pages */
137 err = map_page(va + i, pa + i, _PAGE_KERNEL | _PAGE_NO_CACHE);
138 #endif
140 SetPageReserved(page);
141 page++;
144 /* Free the otherwise unused pages. */
145 while (page < end) {
146 __free_page(page);
147 page++;
150 if (err) {
151 free_pages(vaddr, order);
152 return NULL;
155 return ret;
157 EXPORT_SYMBOL(consistent_alloc);
160 * free page(s) as defined by the above mapping.
162 void consistent_free(size_t size, void *vaddr)
164 struct page *page;
166 if (in_interrupt())
167 BUG();
169 size = PAGE_ALIGN(size);
171 #ifndef CONFIG_MMU
172 /* Clear SHADOW_MASK bit in address, and free as per usual */
173 # ifdef CONFIG_XILINX_UNCACHED_SHADOW
174 vaddr = (void *)((unsigned)vaddr & ~UNCACHED_SHADOW_MASK);
175 # endif
176 page = virt_to_page(vaddr);
178 do {
179 __free_reserved_page(page);
180 page++;
181 } while (size -= PAGE_SIZE);
182 #else
183 do {
184 pte_t *ptep;
185 unsigned long pfn;
187 ptep = pte_offset_kernel(pmd_offset(pgd_offset_k(
188 (unsigned int)vaddr),
189 (unsigned int)vaddr),
190 (unsigned int)vaddr);
191 if (!pte_none(*ptep) && pte_present(*ptep)) {
192 pfn = pte_pfn(*ptep);
193 pte_clear(&init_mm, (unsigned int)vaddr, ptep);
194 if (pfn_valid(pfn)) {
195 page = pfn_to_page(pfn);
196 __free_reserved_page(page);
199 vaddr += PAGE_SIZE;
200 } while (size -= PAGE_SIZE);
202 /* flush tlb */
203 flush_tlb_all();
204 #endif
206 EXPORT_SYMBOL(consistent_free);
209 * make an area consistent.
211 void consistent_sync(void *vaddr, size_t size, int direction)
213 unsigned long start;
214 unsigned long end;
216 start = (unsigned long)vaddr;
218 /* Convert start address back down to unshadowed memory region */
219 #ifdef CONFIG_XILINX_UNCACHED_SHADOW
220 start &= ~UNCACHED_SHADOW_MASK;
221 #endif
222 end = start + size;
224 switch (direction) {
225 case PCI_DMA_NONE:
226 BUG();
227 case PCI_DMA_FROMDEVICE: /* invalidate only */
228 invalidate_dcache_range(start, end);
229 break;
230 case PCI_DMA_TODEVICE: /* writeback only */
231 flush_dcache_range(start, end);
232 break;
233 case PCI_DMA_BIDIRECTIONAL: /* writeback and invalidate */
234 flush_dcache_range(start, end);
235 break;
238 EXPORT_SYMBOL(consistent_sync);
241 * consistent_sync_page makes memory consistent. identical
242 * to consistent_sync, but takes a struct page instead of a
243 * virtual address
245 void consistent_sync_page(struct page *page, unsigned long offset,
246 size_t size, int direction)
248 unsigned long start = (unsigned long)page_address(page) + offset;
249 consistent_sync((void *)start, size, direction);
251 EXPORT_SYMBOL(consistent_sync_page);