fpgafs/files.c

/*********************************************
 * Benjamin Krill <ben@codiert.org>
 *********************************************/
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include "fpgafs.h"

/* generic open function for all pipe-like files */
static int fpgafs_pipe_open(struct inode *inode, struct file *file)
{
	struct fpgafs_inode_info *i = FPGAFS_I(inode);
	file->private_data = i->i_ctx;

  return nonseekable_open(inode, file);
}

static ssize_t fpgafs_stat_read(struct file *file, char __user *buf,
	                              size_t len, loff_t *pos)
{
	struct fpga_context *ctx = file->private_data;
	u32 data, __user *udata;
	ssize_t count;

	if (len < 4)
		return -EINVAL;

	if (!access_ok(VERIFY_WRITE, buf, len))
	return -EFAULT;

	udata = (void __user *)buf;

	for (count = 0; (count + 4) <= len; count += 4, udata++) {
		int ret;

		/* operation to read the status ... */
		data=0x42;
		ret = 0;
		if (ret == 0)
			break;

		ret = __put_user(data, udata);

		if (ret) {
			if (!count)
				count = -EFAULT;
				break;
		}
	}

	if (!count)
		count = -EAGAIN;

	return count;
}

static const struct file_operations fpgafs_stat_fops = {
	.open = fpgafs_pipe_open,
	.read = fpgafs_stat_read,
};

struct tree_descr fpgafs_dir_contents[] = {
#if 0
	{ "cmd",  &fpgafs_cmd_fops,  0222, },
	{ "din",  &spufs_mbox_fops, 0222, },
	{ "dout", &spufs_ibox_fops, 0444, },
	{ "load", &spufs_wbox_fops, 0666, },
#endif
	{ "stat", &fpgafs_stat_fops, 0444, },
	{},
};