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openwrt/target/linux/bcm27xx/patches-5.4/950-0033-amba_pl011-Insert-mb-for-correct-FIFO-handling.patch
John Audia 71b2b32f98 kernel: bump 5.4 to 5.4.74
Removed upstreamed patches:
 mvebu/patches-5.4
   409-phy-marvell-comphy-Convert-internal-SMCC-firmware-re.patch

All modifications made by update_kernel.sh

Build system: x86_64
Build-tested: ipq806x/R7800, ath79/generic, bcm27xx/bcm2711, x86_64
Run-tested: ipq806x/R7800, x86_64, lantiq/Easybox 904 xDSL

No dmesg regressions, everything functional

Signed-off-by: John Audia <graysky@archlinux.us>
Tested-by: Curtis Deptuck <curtdept@me.com> [x86_64 build/run]
[added lantiq test report]
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
2020-11-02 16:33:25 +01:00

28 lines
1014 B
Diff

From 37e06c9ed7219cf6cf08a0463f7e2b5b2c51f3e6 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Fri, 29 Sep 2017 10:32:19 +0100
Subject: [PATCH] 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(+)
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1386,6 +1386,7 @@ static bool pl011_tx_char(struct uart_am
return false; /* unable to transmit character */
pl011_write(c, uap, REG_DR);
+ mb();
uap->port.icount.tx++;
return true;