xref: /openbmc/linux/arch/sh/mm/consistent.c (revision b6dcefde)
1 /*
2  * arch/sh/mm/consistent.c
3  *
4  * Copyright (C) 2004 - 2007  Paul Mundt
5  *
6  * Declared coherent memory functions based on arch/x86/kernel/pci-dma_32.c
7  *
8  * This file is subject to the terms and conditions of the GNU General Public
9  * License.  See the file "COPYING" in the main directory of this archive
10  * for more details.
11  */
12 #include <linux/mm.h>
13 #include <linux/init.h>
14 #include <linux/platform_device.h>
15 #include <linux/dma-mapping.h>
16 #include <linux/dma-debug.h>
17 #include <linux/io.h>
18 #include <linux/module.h>
19 #include <asm/cacheflush.h>
20 #include <asm/addrspace.h>
21 
22 #define PREALLOC_DMA_DEBUG_ENTRIES	4096
23 
24 struct dma_map_ops *dma_ops;
25 EXPORT_SYMBOL(dma_ops);
26 
27 static int __init dma_init(void)
28 {
29 	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
30 	return 0;
31 }
32 fs_initcall(dma_init);
33 
34 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
35 				 dma_addr_t *dma_handle, gfp_t gfp)
36 {
37 	void *ret, *ret_nocache;
38 	int order = get_order(size);
39 
40 	ret = (void *)__get_free_pages(gfp, order);
41 	if (!ret)
42 		return NULL;
43 
44 	memset(ret, 0, size);
45 	/*
46 	 * Pages from the page allocator may have data present in
47 	 * cache. So flush the cache before using uncached memory.
48 	 */
49 	dma_cache_sync(dev, ret, size, DMA_BIDIRECTIONAL);
50 
51 	ret_nocache = (void __force *)ioremap_nocache(virt_to_phys(ret), size);
52 	if (!ret_nocache) {
53 		free_pages((unsigned long)ret, order);
54 		return NULL;
55 	}
56 
57 	split_page(pfn_to_page(virt_to_phys(ret) >> PAGE_SHIFT), order);
58 
59 	*dma_handle = virt_to_phys(ret);
60 
61 	return ret_nocache;
62 }
63 
64 void dma_generic_free_coherent(struct device *dev, size_t size,
65 			       void *vaddr, dma_addr_t dma_handle)
66 {
67 	int order = get_order(size);
68 	unsigned long pfn = dma_handle >> PAGE_SHIFT;
69 	int k;
70 
71 	for (k = 0; k < (1 << order); k++)
72 		__free_pages(pfn_to_page(pfn + k), 0);
73 
74 	iounmap(vaddr);
75 }
76 
77 void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
78 		    enum dma_data_direction direction)
79 {
80 #if defined(CONFIG_CPU_SH5) || defined(CONFIG_PMB)
81 	void *p1addr = vaddr;
82 #else
83 	void *p1addr = (void*) P1SEGADDR((unsigned long)vaddr);
84 #endif
85 
86 	switch (direction) {
87 	case DMA_FROM_DEVICE:		/* invalidate only */
88 		__flush_invalidate_region(p1addr, size);
89 		break;
90 	case DMA_TO_DEVICE:		/* writeback only */
91 		__flush_wback_region(p1addr, size);
92 		break;
93 	case DMA_BIDIRECTIONAL:		/* writeback and invalidate */
94 		__flush_purge_region(p1addr, size);
95 		break;
96 	default:
97 		BUG();
98 	}
99 }
100 EXPORT_SYMBOL(dma_cache_sync);
101 
102 static int __init memchunk_setup(char *str)
103 {
104 	return 1; /* accept anything that begins with "memchunk." */
105 }
106 __setup("memchunk.", memchunk_setup);
107 
108 static void __init memchunk_cmdline_override(char *name, unsigned long *sizep)
109 {
110 	char *p = boot_command_line;
111 	int k = strlen(name);
112 
113 	while ((p = strstr(p, "memchunk."))) {
114 		p += 9; /* strlen("memchunk.") */
115 		if (!strncmp(name, p, k) && p[k] == '=') {
116 			p += k + 1;
117 			*sizep = memparse(p, NULL);
118 			pr_info("%s: forcing memory chunk size to 0x%08lx\n",
119 				name, *sizep);
120 			break;
121 		}
122 	}
123 }
124 
125 int __init platform_resource_setup_memory(struct platform_device *pdev,
126 					  char *name, unsigned long memsize)
127 {
128 	struct resource *r;
129 	dma_addr_t dma_handle;
130 	void *buf;
131 
132 	r = pdev->resource + pdev->num_resources - 1;
133 	if (r->flags) {
134 		pr_warning("%s: unable to find empty space for resource\n",
135 			name);
136 		return -EINVAL;
137 	}
138 
139 	memchunk_cmdline_override(name, &memsize);
140 	if (!memsize)
141 		return 0;
142 
143 	buf = dma_alloc_coherent(NULL, memsize, &dma_handle, GFP_KERNEL);
144 	if (!buf) {
145 		pr_warning("%s: unable to allocate memory\n", name);
146 		return -ENOMEM;
147 	}
148 
149 	memset(buf, 0, memsize);
150 
151 	r->flags = IORESOURCE_MEM;
152 	r->start = dma_handle;
153 	r->end = r->start + memsize - 1;
154 	r->name = name;
155 	return 0;
156 }
157