diff options
Diffstat (limited to 'sys-kernel/boest-v5.0.15/raspberrypi/0033-amba_pl011-Insert-mb-for-correct-FIFO-handling.patch')
| -rw-r--r-- | sys-kernel/boest-v5.0.15/raspberrypi/0033-amba_pl011-Insert-mb-for-correct-FIFO-handling.patch | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/sys-kernel/boest-v5.0.15/raspberrypi/0033-amba_pl011-Insert-mb-for-correct-FIFO-handling.patch b/sys-kernel/boest-v5.0.15/raspberrypi/0033-amba_pl011-Insert-mb-for-correct-FIFO-handling.patch new file mode 100644 index 00000000..ded891ee --- /dev/null +++ b/sys-kernel/boest-v5.0.15/raspberrypi/0033-amba_pl011-Insert-mb-for-correct-FIFO-handling.patch @@ -0,0 +1,29 @@ +From ce0e3f83d941437f16242c8d87b3bf172eaadbd4 Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Fri, 29 Sep 2017 10:32:19 +0100 +Subject: [PATCH 033/194] amba_pl011: Insert mb() for correct FIFO handling + +The pl011 register accessor functions use the _relaxed versions of the +standard readl() and writel() functions, meaning that there are no +automatic memory barriers. When polling a FIFO status register to check +for fullness, it is necessary to ensure that any outstanding writes have +completed; otherwise the flags are effectively stale, making it possible +that the next write is to a full FIFO. + +Signed-off-by: Phil Elwell <phil@raspberrypi.org> +--- + drivers/tty/serial/amba-pl011.c | 1 + + 1 file changed, 1 insertion(+) + +diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c +index 02275f96dbca..39d717e94af3 100644 +--- a/drivers/tty/serial/amba-pl011.c ++++ b/drivers/tty/serial/amba-pl011.c +@@ -1385,6 +1385,7 @@ static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c, + return false; /* unable to transmit character */ + + pl011_write(c, uap, REG_DR); ++ mb(); + uap->port.icount.tx++; + + return true; |