ALSA: firewire-motu: fix truncated bytes in message tracepoints

In MOTU protocol v2/v3, first two data chunks across 2nd and 3rd data
channels includes message bytes from device. The total size of message
is 48 bits per data block.

The 'data_block_message' tracepoints event produced by ALSA firewire-motu
driver exposes the sequence of messages to userspace in 64 bit storage,
however lower 32 bits are actually available since current implementation
truncates 16 bits in upper of the message as a result of bit shift
operation within 32 bit storage.

This commit fixes the bug by perform the bit shift in 64 bit storage.

Fixes: c6b0b9e65f09 ("ALSA: firewire-motu: add tracepoints for messages for unique protocol")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210920110734.27161-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/firewire/motu/amdtp-motu.c b/sound/firewire/motu/amdtp-motu.c
index 5388b85fb60e5a8e887380108031f4f0774d8ba6..a18c2c033e8362e4297183a7be28598ac98143ac 100644 (file)
--- a/sound/firewire/motu/amdtp-motu.c
+++ b/sound/firewire/motu/amdtp-motu.c
@@ -276,10 +276,11 @@ static void __maybe_unused copy_message(u64 *frames, __be32 *buffer,
 
        /* This is just for v2/v3 protocol. */
        for (i = 0; i < data_blocks; ++i) {
-               *frames = (be32_to_cpu(buffer[1]) << 16) |
-                         (be32_to_cpu(buffer[2]) >> 16);
+               *frames = be32_to_cpu(buffer[1]);
+               *frames <<= 16;
+               *frames |= be32_to_cpu(buffer[2]) >> 16;
+               ++frames;
                buffer += data_block_quadlets;
-               frames++;
        }
 }