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8299d1f057
Rebased RPi foundation patches on linux 5.10.59, removed applied and reverted patches, wireless patches and defconfig patches. bcm2708: boot tested on RPi B+ v1.2 bcm2709: boot tested on RPi 4B v1.1 4G bcm2711: boot tested on RPi 4B v1.1 4G Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
28 lines
1014 B
Diff
28 lines
1014 B
Diff
From f44d321993ccf1707f5774dc443b900adae5d9d5 Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Fri, 29 Sep 2017 10:32:19 +0100
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Subject: [PATCH] amba_pl011: Insert mb() for correct FIFO handling
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The pl011 register accessor functions use the _relaxed versions of the
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standard readl() and writel() functions, meaning that there are no
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automatic memory barriers. When polling a FIFO status register to check
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for fullness, it is necessary to ensure that any outstanding writes have
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completed; otherwise the flags are effectively stale, making it possible
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that the next write is to a full FIFO.
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Signed-off-by: Phil Elwell <phil@raspberrypi.org>
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---
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drivers/tty/serial/amba-pl011.c | 1 +
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1 file changed, 1 insertion(+)
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--- a/drivers/tty/serial/amba-pl011.c
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+++ b/drivers/tty/serial/amba-pl011.c
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@@ -1377,6 +1377,7 @@ static bool pl011_tx_char(struct uart_am
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return false; /* unable to transmit character */
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pl011_write(c, uap, REG_DR);
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+ mb();
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uap->port.icount.tx++;
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return true;
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