xen: pvblock: Enumerate virtual block devices

Enumerate Xen virtual block devices found in XenStore and
instantiate pvblock devices.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/xen/pvblock.c

@@ -6,6 +6,10 @@
 #include <common.h>
 #include <dm.h>
 #include <dm/device-internal.h>
+#include <malloc.h>
+#include <part.h>
+
+#include <xen/xenbus.h>
 
 #define DRV_NAME	"pvblock"
 #define DRV_NAME_BLK	"pvblock_blk"
@@ -14,6 +18,10 @@ struct blkfront_dev {
 	char dummy;
 };
 
+struct blkfront_platdata {
+	unsigned int devid;
+};
+
 static int init_blkfront(unsigned int devid, struct blkfront_dev *dev)
 {
 	return 0;
@@ -37,15 +45,40 @@ ulong pvblock_blk_write(struct udevice *udev, lbaint_t blknr, lbaint_t blkcnt,
 
 static int pvblock_blk_bind(struct udevice *udev)
 {
+	struct blk_desc *desc = dev_get_uclass_platdata(udev);
+	int devnum;
+
+	desc->if_type = IF_TYPE_PVBLOCK;
+	/*
+	 * Initialize the devnum to -ENODEV. This is to make sure that
+	 * blk_next_free_devnum() works as expected, since the default
+	 * value 0 is a valid devnum.
+	 */
+	desc->devnum = -ENODEV;
+	devnum = blk_next_free_devnum(IF_TYPE_PVBLOCK);
+	if (devnum < 0)
+		return devnum;
+	desc->devnum = devnum;
+	desc->part_type = PART_TYPE_UNKNOWN;
+	desc->bdev = udev;
+
+	strncpy(desc->vendor, "Xen", sizeof(desc->vendor));
+	strncpy(desc->revision, "1", sizeof(desc->revision));
+	strncpy(desc->product, "Virtual disk", sizeof(desc->product));
+
 	return 0;
 }
 
 static int pvblock_blk_probe(struct udevice *udev)
 {
 	struct blkfront_dev *blk_dev = dev_get_priv(udev);
-	int ret;
+	struct blkfront_platdata *platdata = dev_get_platdata(udev);
+	int ret, devid;
 
-	ret = init_blkfront(0, blk_dev);
+	devid = platdata->devid;
+	free(platdata);
+
+	ret = init_blkfront(devid, blk_dev);
 	if (ret < 0)
 		return ret;
 	return 0;
@@ -79,6 +112,68 @@ U_BOOT_DRIVER(pvblock_blk) = {
  * Para-virtual block device class
  *******************************************************************************/
 
+typedef int (*enum_vbd_callback)(struct udevice *parent, unsigned int devid);
+
+static int on_new_vbd(struct udevice *parent, unsigned int devid)
+{
+	struct driver_info info;
+	struct udevice *udev;
+	struct blkfront_platdata *platdata;
+	int ret;
+
+	debug("New " DRV_NAME_BLK ", device ID %d\n", devid);
+
+	platdata = malloc(sizeof(struct blkfront_platdata));
+	if (!platdata) {
+		printf("Failed to allocate platform data\n");
+		return -ENOMEM;
+	}
+
+	platdata->devid = devid;
+
+	info.name = DRV_NAME_BLK;
+	info.platdata = platdata;
+
+	ret = device_bind_by_name(parent, false, &info, &udev);
+	if (ret < 0) {
+		printf("Failed to bind " DRV_NAME_BLK " to device with ID %d, ret: %d\n",
+		       devid, ret);
+		free(platdata);
+	}
+	return ret;
+}
+
+static int xenbus_enumerate_vbd(struct udevice *udev, enum_vbd_callback clb)
+{
+	char **dirs, *msg;
+	int i, ret;
+
+	msg = xenbus_ls(XBT_NIL, "device/vbd", &dirs);
+	if (msg) {
+		printf("Failed to read device/vbd directory: %s\n", msg);
+		free(msg);
+		return -ENODEV;
+	}
+
+	for (i = 0; dirs[i]; i++) {
+		int devid;
+
+		sscanf(dirs[i], "%d", &devid);
+		ret = clb(udev, devid);
+		if (ret < 0)
+			goto fail;
+
+		free(dirs[i]);
+	}
+	ret = 0;
+
+fail:
+	for (; dirs[i]; i++)
+		free(dirs[i]);
+	free(dirs);
+	return ret;
+}
+
 void pvblock_init(void)
 {
 	struct driver_info info;
@@ -105,6 +200,19 @@ void pvblock_init(void)
 
 static int pvblock_probe(struct udevice *udev)
 {
+	struct uclass *uc;
+	int ret;
+
+	if (xenbus_enumerate_vbd(udev, on_new_vbd) < 0)
+		return -ENODEV;
+
+	ret = uclass_get(UCLASS_BLK, &uc);
+	if (ret)
+		return ret;
+	uclass_foreach_dev_probe(UCLASS_BLK, udev) {
+		if (_ret)
+			return _ret;
+	};
 	return 0;
 }