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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* $Id: flash.c,v 1.25 2001/12/21 04:56:16 davem Exp $
2 * flash.c: Allow mmap access to the OBP Flash, for OBP updates.
3 *
4 * Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be)
5 */
6
7#include <linux/config.h>
8#include <linux/module.h>
9#include <linux/types.h>
10#include <linux/errno.h>
11#include <linux/miscdevice.h>
12#include <linux/slab.h>
13#include <linux/fcntl.h>
14#include <linux/poll.h>
15#include <linux/init.h>
16#include <linux/smp_lock.h>
17#include <linux/spinlock.h>
18
19#include <asm/system.h>
20#include <asm/uaccess.h>
21#include <asm/pgtable.h>
22#include <asm/io.h>
23#include <asm/sbus.h>
24#include <asm/ebus.h>
25#include <asm/upa.h>
26
27static DEFINE_SPINLOCK(flash_lock);
28static struct {
29 unsigned long read_base; /* Physical read address */
30 unsigned long write_base; /* Physical write address */
31 unsigned long read_size; /* Size of read area */
32 unsigned long write_size; /* Size of write area */
33 unsigned long busy; /* In use? */
34} flash;
35
36#define FLASH_MINOR 152
37
38static int
39flash_mmap(struct file *file, struct vm_area_struct *vma)
40{
41 unsigned long addr;
42 unsigned long size;
43
44 spin_lock(&flash_lock);
45 if (flash.read_base == flash.write_base) {
46 addr = flash.read_base;
47 size = flash.read_size;
48 } else {
49 if ((vma->vm_flags & VM_READ) &&
50 (vma->vm_flags & VM_WRITE)) {
51 spin_unlock(&flash_lock);
52 return -EINVAL;
53 }
54 if (vma->vm_flags & VM_READ) {
55 addr = flash.read_base;
56 size = flash.read_size;
57 } else if (vma->vm_flags & VM_WRITE) {
58 addr = flash.write_base;
59 size = flash.write_size;
60 } else {
61 spin_unlock(&flash_lock);
62 return -ENXIO;
63 }
64 }
65 spin_unlock(&flash_lock);
66
67 if ((vma->vm_pgoff << PAGE_SHIFT) > size)
68 return -ENXIO;
69 addr = vma->vm_pgoff + (addr >> PAGE_SHIFT);
70
71 if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size)
72 size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT));
73
74 pgprot_val(vma->vm_page_prot) &= ~(_PAGE_CACHE);
75 pgprot_val(vma->vm_page_prot) |= _PAGE_E;
76 vma->vm_flags |= (VM_SHM | VM_LOCKED);
77
78 if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot))
79 return -EAGAIN;
80
81 return 0;
82}
83
84static long long
85flash_llseek(struct file *file, long long offset, int origin)
86{
87 lock_kernel();
88 switch (origin) {
89 case 0:
90 file->f_pos = offset;
91 break;
92 case 1:
93 file->f_pos += offset;
94 if (file->f_pos > flash.read_size)
95 file->f_pos = flash.read_size;
96 break;
97 case 2:
98 file->f_pos = flash.read_size;
99 break;
100 default:
101 unlock_kernel();
102 return -EINVAL;
103 }
104 unlock_kernel();
105 return file->f_pos;
106}
107
108static ssize_t
109flash_read(struct file * file, char __user * buf,
110 size_t count, loff_t *ppos)
111{
112 unsigned long p = file->f_pos;
113 int i;
114
115 if (count > flash.read_size - p)
116 count = flash.read_size - p;
117
118 for (i = 0; i < count; i++) {
119 u8 data = upa_readb(flash.read_base + p + i);
120 if (put_user(data, buf))
121 return -EFAULT;
122 buf++;
123 }
124
125 file->f_pos += count;
126 return count;
127}
128
129static int
130flash_open(struct inode *inode, struct file *file)
131{
132 if (test_and_set_bit(0, (void *)&flash.busy) != 0)
133 return -EBUSY;
134
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 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 __init flash_init(void)
163{
164 struct sbus_bus *sbus;
165 struct sbus_dev *sdev = NULL;
166#ifdef CONFIG_PCI
167 struct linux_ebus *ebus;
168 struct linux_ebus_device *edev = NULL;
169 struct linux_prom_registers regs[2];
170 int len, nregs;
171#endif
172 int err;
173
174 for_all_sbusdev(sdev, sbus) {
175 if (!strcmp(sdev->prom_name, "flashprom")) {
176 if (sdev->reg_addrs[0].phys_addr == sdev->reg_addrs[1].phys_addr) {
177 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
178 (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
179 flash.read_size = sdev->reg_addrs[0].reg_size;
180 flash.write_base = flash.read_base;
181 flash.write_size = flash.read_size;
182 } else {
183 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
184 (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
185 flash.read_size = sdev->reg_addrs[0].reg_size;
186 flash.write_base = ((unsigned long)sdev->reg_addrs[1].phys_addr) |
187 (((unsigned long)sdev->reg_addrs[1].which_io)<<32UL);
188 flash.write_size = sdev->reg_addrs[1].reg_size;
189 }
190 flash.busy = 0;
191 break;
192 }
193 }
194 if (!sdev) {
195#ifdef CONFIG_PCI
196 for_each_ebus(ebus) {
197 for_each_ebusdev(edev, ebus) {
198 if (!strcmp(edev->prom_name, "flashprom"))
199 goto ebus_done;
200 }
201 }
202 ebus_done:
203 if (!edev)
204 return -ENODEV;
205
206 len = prom_getproperty(edev->prom_node, "reg", (void *)regs, sizeof(regs));
207 if ((len % sizeof(regs[0])) != 0) {
208 printk("flash: Strange reg property size %d\n", len);
209 return -ENODEV;
210 }
211
212 nregs = len / sizeof(regs[0]);
213
214 flash.read_base = edev->resource[0].start;
215 flash.read_size = regs[0].reg_size;
216
217 if (nregs == 1) {
218 flash.write_base = edev->resource[0].start;
219 flash.write_size = regs[0].reg_size;
220 } else if (nregs == 2) {
221 flash.write_base = edev->resource[1].start;
222 flash.write_size = regs[1].reg_size;
223 } else {
224 printk("flash: Strange number of regs %d\n", nregs);
225 return -ENODEV;
226 }
227
228 flash.busy = 0;
229
230#else
231 return -ENODEV;
232#endif
233 }
234
235 printk("OBP Flash: RD %lx[%lx] WR %lx[%lx]\n",
236 flash.read_base, flash.read_size,
237 flash.write_base, flash.write_size);
238
239 err = misc_register(&flash_dev);
240 if (err) {
241 printk(KERN_ERR "flash: unable to get misc minor\n");
242 return err;
243 }
244
245 return 0;
246}
247
248static void __exit flash_cleanup(void)
249{
250 misc_deregister(&flash_dev);
251}
252
253module_init(flash_init);
254module_exit(flash_cleanup);
255MODULE_LICENSE("GPL");