+struct dbfs_d204_hdr {
+ u64 len; /* Length of d204 buffer without header */
+ u16 version; /* Version of header */
+ u8 sc; /* Used subcode */
+ char reserved[53];
+} __attribute__ ((packed));
+
+struct dbfs_d204 {
+ struct dbfs_d204_hdr hdr; /* 64 byte header */
+ char buf[]; /* d204 buffer */
+} __attribute__ ((packed));
+
+struct dbfs_d204_private {
+ struct dbfs_d204 *d204; /* Aligned d204 data with header */
+ void *base; /* Base pointer (needed for vfree) */
+};
+
+static int dbfs_d204_open(struct inode *inode, struct file *file)
+{
+ struct dbfs_d204_private *data;
+ struct dbfs_d204 *d204;
+ int rc, buf_size;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+ buf_size = PAGE_SIZE * (diag204_buf_pages + 1) + sizeof(d204->hdr);
+ data->base = vmalloc(buf_size);
+ if (!data->base) {
+ rc = -ENOMEM;
+ goto fail_kfree_data;
+ }
+ memset(data->base, 0, buf_size);
+ d204 = page_align_ptr(data->base + sizeof(d204->hdr))
+ - sizeof(d204->hdr);
+ rc = diag204_do_store(&d204->buf, diag204_buf_pages);
+ if (rc)
+ goto fail_vfree_base;
+ d204->hdr.version = DBFS_D204_HDR_VERSION;
+ d204->hdr.len = PAGE_SIZE * diag204_buf_pages;
+ d204->hdr.sc = diag204_store_sc;
+ data->d204 = d204;
+ file->private_data = data;
+ return nonseekable_open(inode, file);
+
+fail_vfree_base:
+ vfree(data->base);
+fail_kfree_data:
+ kfree(data);
+ return rc;
+}
+
+static int dbfs_d204_release(struct inode *inode, struct file *file)
+{
+ struct dbfs_d204_private *data = file->private_data;
+
+ vfree(data->base);
+ kfree(data);
+ return 0;
+}
+
+static ssize_t dbfs_d204_read(struct file *file, char __user *buf,
+ size_t size, loff_t *ppos)
+{
+ struct dbfs_d204_private *data = file->private_data;
+
+ return simple_read_from_buffer(buf, size, ppos, data->d204,
+ data->d204->hdr.len +
+ sizeof(data->d204->hdr));
+}
+
+static const struct file_operations dbfs_d204_ops = {
+ .open = dbfs_d204_open,
+ .read = dbfs_d204_read,
+ .release = dbfs_d204_release,
+};
+
+static int hypfs_dbfs_init(void)
+{
+ dbfs_d204_file = debugfs_create_file("diag_204", 0400, hypfs_dbfs_dir,
+ NULL, &dbfs_d204_ops);
+ if (IS_ERR(dbfs_d204_file))
+ return PTR_ERR(dbfs_d204_file);
+ return 0;
+}
+