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1/* flash.c: Allow mmap access to the OBP Flash, for OBP updates.
2 *
3 * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be)
4 */
5
6#include <linux/module.h>
7#include <linux/types.h>
8#include <linux/errno.h>
9#include <linux/miscdevice.h>
10#include <linux/fcntl.h>
11#include <linux/poll.h>
12#include <linux/init.h>
13#include <linux/mutex.h>
14#include <linux/spinlock.h>
15#include <linux/mm.h>
16#include <linux/of.h>
17#include <linux/of_device.h>
18
19#include <asm/uaccess.h>
20#include <asm/pgtable.h>
21#include <asm/io.h>
22#include <asm/upa.h>
23
24static DEFINE_MUTEX(flash_mutex);
25static DEFINE_SPINLOCK(flash_lock);
26static struct {
27 unsigned long read_base; /* Physical read address */
28 unsigned long write_base; /* Physical write address */
29 unsigned long read_size; /* Size of read area */
30 unsigned long write_size; /* Size of write area */
31 unsigned long busy; /* In use? */
32} flash;
33
34#define FLASH_MINOR 152
35
36static int
37flash_mmap(struct file *file, struct vm_area_struct *vma)
38{
39 unsigned long addr;
40 unsigned long size;
41
42 spin_lock(&flash_lock);
43 if (flash.read_base == flash.write_base) {
44 addr = flash.read_base;
45 size = flash.read_size;
46 } else {
47 if ((vma->vm_flags & VM_READ) &&
48 (vma->vm_flags & VM_WRITE)) {
49 spin_unlock(&flash_lock);
50 return -EINVAL;
51 }
52 if (vma->vm_flags & VM_READ) {
53 addr = flash.read_base;
54 size = flash.read_size;
55 } else if (vma->vm_flags & VM_WRITE) {
56 addr = flash.write_base;
57 size = flash.write_size;
58 } else {
59 spin_unlock(&flash_lock);
60 return -ENXIO;
61 }
62 }
63 spin_unlock(&flash_lock);
64
65 if ((vma->vm_pgoff << PAGE_SHIFT) > size)
66 return -ENXIO;
67 addr = vma->vm_pgoff + (addr >> PAGE_SHIFT);
68
69 if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size)
70 size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT));
71
72 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
73
74 if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot))
75 return -EAGAIN;
76
77 return 0;
78}
79
80static long long
81flash_llseek(struct file *file, long long offset, int origin)
82{
83 mutex_lock(&flash_mutex);
84 switch (origin) {
85 case 0:
86 file->f_pos = offset;
87 break;
88 case 1:
89 file->f_pos += offset;
90 if (file->f_pos > flash.read_size)
91 file->f_pos = flash.read_size;
92 break;
93 case 2:
94 file->f_pos = flash.read_size;
95 break;
96 default:
97 mutex_unlock(&flash_mutex);
98 return -EINVAL;
99 }
100 mutex_unlock(&flash_mutex);
101 return file->f_pos;
102}
103
104static ssize_t
105flash_read(struct file * file, char __user * buf,
106 size_t count, loff_t *ppos)
107{
108 loff_t p = *ppos;
109 int i;
110
111 if (count > flash.read_size - p)
112 count = flash.read_size - p;
113
114 for (i = 0; i < count; i++) {
115 u8 data = upa_readb(flash.read_base + p + i);
116 if (put_user(data, buf))
117 return -EFAULT;
118 buf++;
119 }
120
121 *ppos += count;
122 return count;
123}
124
125static int
126flash_open(struct inode *inode, struct file *file)
127{
128 mutex_lock(&flash_mutex);
129 if (test_and_set_bit(0, (void *)&flash.busy) != 0) {
130 mutex_unlock(&flash_mutex);
131 return -EBUSY;
132 }
133
134 mutex_unlock(&flash_mutex);
135 return 0;
136}
137
138static int
139flash_release(struct inode *inode, struct file *file)
140{
141 spin_lock(&flash_lock);
142 flash.busy = 0;
143 spin_unlock(&flash_lock);
144
145 return 0;
146}
147
148static const struct file_operations flash_fops = {
149 /* no write to the Flash, use mmap
150 * and play flash dependent tricks.
151 */
152 .owner = THIS_MODULE,
153 .llseek = flash_llseek,
154 .read = flash_read,
155 .mmap = flash_mmap,
156 .open = flash_open,
157 .release = flash_release,
158};
159
160static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };
161
162static int __devinit flash_probe(struct platform_device *op)
163{
164 struct device_node *dp = op->dev.of_node;
165 struct device_node *parent;
166
167 parent = dp->parent;
168
169 if (strcmp(parent->name, "sbus") &&
170 strcmp(parent->name, "sbi") &&
171 strcmp(parent->name, "ebus"))
172 return -ENODEV;
173
174 flash.read_base = op->resource[0].start;
175 flash.read_size = resource_size(&op->resource[0]);
176 if (op->resource[1].flags) {
177 flash.write_base = op->resource[1].start;
178 flash.write_size = resource_size(&op->resource[1]);
179 } else {
180 flash.write_base = op->resource[0].start;
181 flash.write_size = resource_size(&op->resource[0]);
182 }
183 flash.busy = 0;
184
185 printk(KERN_INFO "%s: OBP Flash, RD %lx[%lx] WR %lx[%lx]\n",
186 op->dev.of_node->full_name,
187 flash.read_base, flash.read_size,
188 flash.write_base, flash.write_size);
189
190 return misc_register(&flash_dev);
191}
192
193static int __devexit flash_remove(struct platform_device *op)
194{
195 misc_deregister(&flash_dev);
196
197 return 0;
198}
199
200static const struct of_device_id flash_match[] = {
201 {
202 .name = "flashprom",
203 },
204 {},
205};
206MODULE_DEVICE_TABLE(of, flash_match);
207
208static struct platform_driver flash_driver = {
209 .driver = {
210 .name = "flash",
211 .owner = THIS_MODULE,
212 .of_match_table = flash_match,
213 },
214 .probe = flash_probe,
215 .remove = __devexit_p(flash_remove),
216};
217
218module_platform_driver(flash_driver);
219
220MODULE_LICENSE("GPL");