Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

Linux/drivers/sbus/char/flash.c

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

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us