patch-2.4.6 linux/drivers/mtd/mtdblock_ro.c

• Lines: 290
• Date: Tue Jun 12 10:30:27 2001
• Orig file: v2.4.5/linux/drivers/mtd/mtdblock_ro.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.5/linux/drivers/mtd/mtdblock_ro.c linux/drivers/mtd/mtdblock_ro.c
@@ -0,0 +1,289 @@
+/*
+ * $Id: mtdblock_ro.c,v 1.5 2001/06/10 01:41:53 dwmw2 Exp $
+ *
+ * Read-only version of the mtdblock device, without the 
+ * read/erase/modify/writeback stuff
+ */
+
+#ifdef MTDBLOCK_DEBUG
+#define DEBUGLVL debug
+#endif							       
+
+
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include <linux/mtd/mtd.h>
+
+#define MAJOR_NR MTD_BLOCK_MAJOR
+#define DEVICE_NAME "mtdblock"
+#define DEVICE_REQUEST mtdblock_request
+#define DEVICE_NR(device) (device)
+#define DEVICE_ON(device)
+#define DEVICE_OFF(device)
+#define DEVICE_NO_RANDOM
+#include <linux/blk.h>
+
+#if LINUX_VERSION_CODE < 0x20300
+#define RQFUNC_ARG void
+#define blkdev_dequeue_request(req) do {CURRENT = req->next;} while (0)
+#else
+#define RQFUNC_ARG request_queue_t *q
+#endif
+
+#ifdef MTDBLOCK_DEBUG
+static int debug = MTDBLOCK_DEBUG;
+MODULE_PARM(debug, "i");
+#endif
+
+
+static int mtd_sizes[MAX_MTD_DEVICES];
+
+
+static int mtdblock_open(struct inode *inode, struct file *file)
+{
+	struct mtd_info *mtd = NULL;
+
+	int dev;
+
+	DEBUG(1,"mtdblock_open\n");
+	
+	if (inode == 0)
+		return -EINVAL;
+	
+	dev = MINOR(inode->i_rdev);
+	
+	MOD_INC_USE_COUNT;
+
+	mtd = get_mtd_device(NULL, dev);
+
+	if (!mtd) {
+		MOD_DEC_USE_COUNT;
+		return -ENODEV;
+	}
+
+	mtd_sizes[dev] = mtd->size>>9;
+
+	DEBUG(1, "ok\n");
+
+	return 0;
+}
+
+static release_t mtdblock_release(struct inode *inode, struct file *file)
+{
+	int dev;
+	struct mtd_info *mtd;
+
+   	DEBUG(1, "mtdblock_release\n");
+
+	if (inode == NULL)
+		release_return(-ENODEV);
+   
+	invalidate_device(inode->i_rdev, 1);
+
+	dev = MINOR(inode->i_rdev);
+	mtd = __get_mtd_device(NULL, dev);
+
+	if (!mtd) {
+		printk(KERN_WARNING "MTD device is absent on mtd_release!\n");
+		MOD_DEC_USE_COUNT;
+		release_return(-ENODEV);
+	}
+	
+	if (mtd->sync)
+		mtd->sync(mtd);
+
+	put_mtd_device(mtd);
+
+	DEBUG(1, "ok\n");
+
+	MOD_DEC_USE_COUNT;
+	release_return(0);
+}  
+
+
+static void mtdblock_request(RQFUNC_ARG)
+{
+   struct request *current_request;
+   unsigned int res = 0;
+   struct mtd_info *mtd;
+
+   while (1)
+   {
+      /* Grab the Request and unlink it from the request list, INIT_REQUEST
+       	 will execute a return if we are done. */
+      INIT_REQUEST;
+      current_request = CURRENT;
+   
+      if (MINOR(current_request->rq_dev) >= MAX_MTD_DEVICES)
+      {
+	 printk("mtd: Unsupported device!\n");
+	 end_request(0);
+	 continue;
+      }
+      
+      // Grab our MTD structure
+
+      mtd = __get_mtd_device(NULL, MINOR(current_request->rq_dev));
+      if (!mtd) {
+	      printk("MTD device %d doesn't appear to exist any more\n", CURRENT_DEV);
+	      end_request(0);
+      }
+
+      if (current_request->sector << 9 > mtd->size ||
+	  (current_request->sector + current_request->nr_sectors) << 9 > mtd->size)
+      {
+	 printk("mtd: Attempt to read past end of device!\n");
+	 printk("size: %x, sector: %lx, nr_sectors %lx\n", mtd->size, current_request->sector, current_request->nr_sectors);
+	 end_request(0);
+	 continue;
+      }
+      
+      /* Remove the request we are handling from the request list so nobody messes
+         with it */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
+      /* Now drop the lock that the ll_rw_blk functions grabbed for us
+         and process the request. This is necessary due to the extreme time
+         we spend processing it. */
+      spin_unlock_irq(&io_request_lock);
+#endif
+
+      // Handle the request
+      switch (current_request->cmd)
+      {
+         size_t retlen;
+
+	 case READ:
+	 if (MTD_READ(mtd,current_request->sector<<9, 
+		      current_request->nr_sectors << 9, 
+		      &retlen, current_request->buffer) == 0)
+	    res = 1;
+	 else
+	    res = 0;
+	 break;
+	 
+	 case WRITE:
+
+	 /* printk("mtdblock_request WRITE sector=%d(%d)\n",current_request->sector,
+		current_request->nr_sectors);
+	 */
+
+	 // Read only device
+	 if ((mtd->flags & MTD_CAP_RAM) == 0)
+	 {
+	    res = 0;
+	    break;
+	 }
+
+	 // Do the write
+	 if (MTD_WRITE(mtd,current_request->sector<<9, 
+		       current_request->nr_sectors << 9, 
+		       &retlen, current_request->buffer) == 0)
+	    res = 1;
+	 else
+	    res = 0;
+	 break;
+	 
+	 // Shouldn't happen
+	 default:
+	 printk("mtd: unknown request\n");
+	 break;
+      }
+
+      // Grab the lock and re-thread the item onto the linked list
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
+	spin_lock_irq(&io_request_lock);
+#endif
+	end_request(res);
+   }
+}
+
+
+
+static int mtdblock_ioctl(struct inode * inode, struct file * file,
+		      unsigned int cmd, unsigned long arg)
+{
+	struct mtd_info *mtd;
+
+	mtd = __get_mtd_device(NULL, MINOR(inode->i_rdev));
+
+	if (!mtd) return -EINVAL;
+
+	switch (cmd) {
+	case BLKGETSIZE:   /* Return device size */
+		if (!arg)  return -EFAULT;
+		return Put_user((mtd->size >> 9),
+                                (long *) arg);
+		
+	case BLKFLSBUF:
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0)
+		if(!capable(CAP_SYS_ADMIN))  return -EACCES;
+#endif
+		fsync_dev(inode->i_rdev);
+		invalidate_buffers(inode->i_rdev);
+		if (mtd->sync)
+			mtd->sync(mtd);
+		return 0;
+
+	default:
+		return -ENOTTY;
+	}
+}
+
+#if LINUX_VERSION_CODE < 0x20326
+static struct file_operations mtd_fops =
+{
+	open: mtdblock_open,
+	ioctl: mtdblock_ioctl,
+	release: mtdblock_release,
+	read: block_read,
+	write: block_write
+};
+#else
+static struct block_device_operations mtd_fops = 
+{
+	open: mtdblock_open,
+	release: mtdblock_release,
+	ioctl: mtdblock_ioctl
+};
+#endif
+
+#if LINUX_VERSION_CODE < 0x20212 && defined(MODULE)
+#define init_mtdblock init_module
+#define cleanup_mtdblock cleanup_module
+#endif
+
+int __init init_mtdblock(void)
+{
+	int i;
+
+	if (register_blkdev(MAJOR_NR,DEVICE_NAME,&mtd_fops)) {
+		printk(KERN_NOTICE "Can't allocate major number %d for Memory Technology Devices.\n",
+		       MTD_BLOCK_MAJOR);
+		return EAGAIN;
+	}
+	
+	/* We fill it in at open() time. */
+	for (i=0; i< MAX_MTD_DEVICES; i++) {
+		mtd_sizes[i] = 0;
+	}
+	
+	/* Allow the block size to default to BLOCK_SIZE. */
+	blksize_size[MAJOR_NR] = NULL;
+	blk_size[MAJOR_NR] = mtd_sizes;
+	
+#if LINUX_VERSION_CODE < 0x20320
+	blk_dev[MAJOR_NR].request_fn = mtdblock_request;
+#else
+	blk_init_queue(BLK_DEFAULT_QUEUE(MAJOR_NR), &mtdblock_request);
+#endif
+	return 0;
+}
+
+static void __exit cleanup_mtdblock(void)
+{
+	unregister_blkdev(MAJOR_NR,DEVICE_NAME);
+}
+
+module_init(init_mtdblock);
+module_exit(cleanup_mtdblock);