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-rw-r--r--Documentation/printk-formats.txt5
-rw-r--r--lib/vsprintf.c23
2 files changed, 24 insertions, 4 deletions
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 5df176ed59b8..d8d168fa79d6 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -56,6 +56,7 @@ Struct Resources:
MAC/FDDI addresses:
%pM 00:01:02:03:04:05
+ %pMR 05:04:03:02:01:00
%pMF 00-01-02-03-04-05
%pm 000102030405
@@ -67,6 +68,10 @@ MAC/FDDI addresses:
the 'M' specifier to use dash ('-') separators instead of the default
separator.
+ For Bluetooth addresses the 'R' specifier shall be used after the 'M'
+ specifier to use reversed byte order suitable for visual interpretation
+ of Bluetooth addresses which are in the little endian order.
+
IPv4 addresses:
%pI4 1.2.3.4
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index c3f36d415bdf..736974576e2d 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -662,15 +662,28 @@ char *mac_address_string(char *buf, char *end, u8 *addr,
char *p = mac_addr;
int i;
char separator;
+ bool reversed = false;
- if (fmt[1] == 'F') { /* FDDI canonical format */
+ switch (fmt[1]) {
+ case 'F':
separator = '-';
- } else {
+ break;
+
+ case 'R':
+ reversed = true;
+ /* fall through */
+
+ default:
separator = ':';
+ break;
}
for (i = 0; i < 6; i++) {
- p = hex_byte_pack(p, addr[i]);
+ if (reversed)
+ p = hex_byte_pack(p, addr[5 - i]);
+ else
+ p = hex_byte_pack(p, addr[i]);
+
if (fmt[0] == 'M' && i != 5)
*p++ = separator;
}
@@ -933,6 +946,7 @@ int kptr_restrict __read_mostly;
* - 'm' For a 6-byte MAC address, it prints the hex address without colons
* - 'MF' For a 6-byte MAC FDDI address, it prints the address
* with a dash-separated hex notation
+ * - '[mM]R For a 6-byte MAC address, Reverse order (Bluetooth)
* - 'I' [46] for IPv4/IPv6 addresses printed in the usual way
* IPv4 uses dot-separated decimal without leading 0's (1.2.3.4)
* IPv6 uses colon separated network-order 16 bit hex with leading 0's
@@ -995,7 +1009,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
return resource_string(buf, end, ptr, spec, fmt);
case 'M': /* Colon separated: 00:01:02:03:04:05 */
case 'm': /* Contiguous: 000102030405 */
- /* [mM]F (FDDI, bit reversed) */
+ /* [mM]F (FDDI) */
+ /* [mM]R (Reverse order; Bluetooth) */
return mac_address_string(buf, end, ptr, spec, fmt);
case 'I': /* Formatted IP supported
* 4: 1.2.3.4