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Drop UART write retry patch from U-Boot (#873)

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The patch causes U-Boot freezes in some configurations. The root cause
is that U-Boot does not allow to use the bss section in pre-relocation
code (which is where the UART is used). Drop the patch as it is not
required currently.

See also:
http://u-boot.10912.n7.nabble.com/RPi4-U-Boot-freeze-td424432.html#a427198
This commit is contained in:
Stefan Agner 2020-09-24 13:37:44 +02:00 committed by GitHub
parent 3af31c2265
commit ebc93692f5
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1 changed files with 0 additions and 49 deletions
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49
buildroot-external/board/raspberrypi/patches/uboot/0002-avoid-block-uart-write.patch
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@ -1,49 +0,0 @@
From 5e960cc9b208c53d5385d5a2f6c7f380e9499d4c Mon Sep 17 00:00:00 2001
From: Alexandru Costache <alexandru@balena.io>
Date: Wed, 18 Mar 2020 16:54:28 +0100
Subject: [PATCH] Add a retry limit when writing to uart console
Seems that if the serial console is incorrectly
configured in the dtb, writing to it may block indefinitely,
thus preventing the board from booting.
Let's add a retry count to unblock in such cases.
Upstream-status: Inappropriate [configuration]
Signed-off-by: Alexandru Costache <alexandru@balena.io>
---
drivers/serial/serial_bcm283x_mu.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/serial/serial_bcm283x_mu.c b/drivers/serial/serial_bcm283x_mu.c
index bd1d89ec83..bd033d14c4 100644
--- a/drivers/serial/serial_bcm283x_mu.c
+++ b/drivers/serial/serial_bcm283x_mu.c
@@ -49,7 +49,7 @@ struct bcm283x_mu_regs {
struct bcm283x_mu_priv {
struct bcm283x_mu_regs *regs;
};
-
+static uint16_t putc_retry = 0;
static int bcm283x_mu_serial_getc(struct udevice *dev);
static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate)
@@ -105,8 +105,14 @@ static int bcm283x_mu_serial_putc(struct udevice *dev, const char data)
struct bcm283x_mu_regs *regs = priv->regs;
/* Wait until there is space in the FIFO */
- if (!(readl(&regs->lsr) & BCM283X_MU_LSR_TX_EMPTY))
- return -EAGAIN;
+ if (!(readl(&regs->lsr) & BCM283X_MU_LSR_TX_EMPTY)) {
+ if (++putc_retry) {
+ return -EAGAIN;
+ } else {
+ /* Couldn't write for too long, drop char */
+ return 0;
+ }
+ }
/* Send the character */
writel(data, &regs->io);
--
2.17.1