disk: introduce get_device()

This patch introduces function get_device(). This looks up a
block_dev_desc_t from an interface name (e.g. mmc) and device number
(e.g. 0). This function is essentially the non-partition-specific
prefix of get_device_and_partition().
Signed-off-by: NStephen Warren <swarren@nvidia.com>

disk/part.c

@@ -443,6 +443,28 @@ int get_partition_info(block_dev_desc_t *dev_desc, int part
 	return -1;
 }
 
+int get_device(const char *ifname, const char *dev_str,
+	       block_dev_desc_t **dev_desc)
+{
+	char *ep;
+	int dev;
+
+	dev = simple_strtoul(dev_str, &ep, 16);
+	if (*ep) {
+		printf("** Bad device specification %s %s **\n",
+		       ifname, dev_str);
+		return -1;
+	}
+
+	*dev_desc = get_dev(ifname, dev);
+	if (!(*dev_desc) || ((*dev_desc)->type == DEV_TYPE_UNKNOWN)) {
+		printf("** Bad device %s %s **\n", ifname, dev_str);
+		return -1;
+	}
+
+	return dev;
+}
+
 int get_device_and_partition(const char *ifname, const char *dev_str,
 			     block_dev_desc_t **dev_desc,
 			     disk_partition_t *info)

include/part.h

@@ -112,6 +112,8 @@ int get_partition_info (block_dev_desc_t * dev_desc, int part, disk_partition_t
 void print_part (block_dev_desc_t *dev_desc);
 void  init_part (block_dev_desc_t *dev_desc);
 void dev_print(block_dev_desc_t *dev_desc);
+int get_device(const char *ifname, const char *dev_str,
+	       block_dev_desc_t **dev_desc);
 int get_device_and_partition(const char *ifname, const char *dev_str,
 			     block_dev_desc_t **dev_desc,
 			     disk_partition_t *info);
@@ -131,6 +133,9 @@ static inline int get_partition_info (block_dev_desc_t * dev_desc, int part,
 static inline void print_part (block_dev_desc_t *dev_desc) {}
 static inline void  init_part (block_dev_desc_t *dev_desc) {}
 static inline void dev_print(block_dev_desc_t *dev_desc) {}
+static inline int get_device(const char *ifname, const char *dev_str,
+	       block_dev_desc_t **dev_desc)
+{ return -1; }
 static inline int get_device_and_partition(const char *ifname,
 					   const char *dev_str,
 					   block_dev_desc_t **dev_desc,