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authorWill Deacon <will.deacon@arm.com>2019-02-22 17:14:59 +0000
committerWill Deacon <will.deacon@arm.com>2019-04-08 12:01:02 +0100
commitfb24ea52f78e0d595852e09e3a55697c8f442189 (patch)
tree00ca29c7b0b8df6258a1ad1faf34f6e838ada26c /drivers/tty
parent949b8c72768e3a7c69d270962b8a142ee8deec1b (diff)
downloadlinux-fb24ea52f78e0d595852e09e3a55697c8f442189.tar.bz2
drivers: Remove explicit invocations of mmiowb()
mmiowb() is now implied by spin_unlock() on architectures that require it, so there is no reason to call it from driver code. This patch was generated using coccinelle: @mmiowb@ @@ - mmiowb(); and invoked as: $ for d in drivers include/linux/qed sound; do \ spatch --include-headers --sp-file mmiowb.cocci --dir $d --in-place; done NOTE: mmiowb() has only ever guaranteed ordering in conjunction with spin_unlock(). However, pairing each mmiowb() removal in this patch with the corresponding call to spin_unlock() is not at all trivial, so there is a small chance that this change may regress any drivers incorrectly relying on mmiowb() to order MMIO writes between CPUs using lock-free synchronisation. If you've ended up bisecting to this commit, you can reintroduce the mmiowb() calls using wmb() instead, which should restore the old behaviour on all architectures other than some esoteric ia64 systems. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/men_z135_uart.c1
-rw-r--r--drivers/tty/serial/serial_txx9.c1
2 files changed, 0 insertions, 2 deletions
diff --git a/drivers/tty/serial/men_z135_uart.c b/drivers/tty/serial/men_z135_uart.c
index ef89534dd760..e5d3ebab6dae 100644
--- a/drivers/tty/serial/men_z135_uart.c
+++ b/drivers/tty/serial/men_z135_uart.c
@@ -353,7 +353,6 @@ static void men_z135_handle_tx(struct men_z135_port *uart)
memcpy_toio(port->membase + MEN_Z135_TX_RAM, &xmit->buf[xmit->tail], n);
xmit->tail = (xmit->tail + n) & (UART_XMIT_SIZE - 1);
- mmiowb();
iowrite32(n & 0x3ff, port->membase + MEN_Z135_TX_CTRL);
diff --git a/drivers/tty/serial/serial_txx9.c b/drivers/tty/serial/serial_txx9.c
index 1b4008d022bf..d22ccb32aa9b 100644
--- a/drivers/tty/serial/serial_txx9.c
+++ b/drivers/tty/serial/serial_txx9.c
@@ -248,7 +248,6 @@ static void serial_txx9_initialize(struct uart_port *port)
sio_out(up, TXX9_SIFCR, TXX9_SIFCR_SWRST);
/* TX4925 BUG WORKAROUND. Accessing SIOC register
* immediately after soft reset causes bus error. */
- mmiowb();
udelay(1);
while ((sio_in(up, TXX9_SIFCR) & TXX9_SIFCR_SWRST) && --tmout)
udelay(1);