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authorArnd Bergmann <arnd@arndb.de>2016-01-25 22:54:56 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-02-06 23:41:17 -0800
commita4f642a8a3c2838ad09fe8313d45db46600e1478 (patch)
tree8209b9db3abaed782711e4d9213555b277616b97 /drivers/tty/nozomi.c
parent04b757dfd26cee24bc62ed815cd87efbf10ef2fc (diff)
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tty: nozomi: avoid a harmless gcc warning
The nozomi wireless data driver has its own helper function to transfer data from a FIFO, doing an extra byte swap on big-endian architectures, presumably to bring the data back into byte-serial order after readw() or readl() perform their implicit byteswap. This helper function is used in the receive_data() function to first read the length into a 32-bit variable, which causes a compile-time warning: drivers/tty/nozomi.c: In function 'receive_data': drivers/tty/nozomi.c:857:9: warning: 'size' may be used uninitialized in this function [-Wmaybe-uninitialized] The problem is that gcc is unsure whether the data was actually read or not. We know that it is at this point, so we can replace it with a single readl() to shut up that warning. I am leaving the byteswap in there, to preserve the existing behavior, even though this seems fishy: Reading the length of the data into a cpu-endian variable should normally not use a second byteswap on big-endian systems, unless the hardware is aware of the CPU endianess. There appears to be a lot more confusion about endianess in this driver, so it probably has not worked on big-endian systems in a long time, if ever, and I have no way to test it. It's well possible that this driver has not been used by anyone in a while, the last patch that looks like it was tested on the hardware is from 2008. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/nozomi.c')
-rw-r--r--drivers/tty/nozomi.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/tty/nozomi.c b/drivers/tty/nozomi.c
index 80f9de907563..5cc80b80c82b 100644
--- a/drivers/tty/nozomi.c
+++ b/drivers/tty/nozomi.c
@@ -823,7 +823,7 @@ static int receive_data(enum port_type index, struct nozomi *dc)
struct tty_struct *tty = tty_port_tty_get(&port->port);
int i, ret;
- read_mem32((u32 *) &size, addr, 4);
+ size = __le32_to_cpu(readl(addr));
/* DBG1( "%d bytes port: %d", size, index); */
if (tty && test_bit(TTY_THROTTLED, &tty->flags)) {