The relevant sequences consist of two I/O memory writes. The second write depends on the first one. mmiowb() was inserted to make sure that no other thread inserts a "first write" before the current one finished its second. As a mutex protects this critical sequence, mmiowb() is unnecessary. Signed-off-by: Eli Billauer <eli.billauer@xxxxxxxxx> --- drivers/staging/xillybus/xillybus_core.c | 4 ---- 1 files changed, 0 insertions(+), 4 deletions(-) diff --git a/drivers/staging/xillybus/xillybus_core.c b/drivers/staging/xillybus/xillybus_core.c index 93a3c61..138c069 100644 --- a/drivers/staging/xillybus/xillybus_core.c +++ b/drivers/staging/xillybus/xillybus_core.c @@ -908,8 +908,6 @@ static ssize_t xillybus_read(struct file *filp, char __user *userbuf, channel->endpoint->registers + fpga_buf_ctrl_reg); - mmiowb(); /* Just to appear safe */ - mutex_unlock(&channel->endpoint-> register_mutex); } @@ -1118,7 +1116,6 @@ static int xillybus_myflush(struct xilly_channel *channel, long timeout) (2 << 24) | /* Opcode 2, submit buffer */ (bufidx << 12), channel->endpoint->registers + fpga_buf_ctrl_reg); - mmiowb(); /* Just to appear safe */ mutex_unlock(&channel->endpoint->register_mutex); } else if (bufidx == 0) @@ -1369,7 +1366,6 @@ static ssize_t xillybus_write(struct file *filp, const char __user *userbuf, (bufidx << 12), channel->endpoint->registers + fpga_buf_ctrl_reg); - mmiowb(); /* Just to appear safe */ mutex_unlock(&channel->endpoint-> register_mutex); -- 1.7.2.3 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
