You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
48 lines
1.7 KiB
Diff
48 lines
1.7 KiB
Diff
From ca1ca821f735ad6284fa0c6228f27415e90f7a8f Mon Sep 17 00:00:00 2001
|
|
From: Phil Elwell <phil@raspberrypi.org>
|
|
Date: Fri, 29 Sep 2017 10:32:19 +0100
|
|
Subject: [PATCH 122/454] amba_pl011: Add cts-event-workaround DT property
|
|
|
|
The BCM2835 PL011 implementation seems to have a bug that can lead to a
|
|
transmission lockup if CTS changes frequently. A workaround was added to
|
|
the driver with a vendor-specific flag to enable it, but this flag is
|
|
currently not set for ARM implementations.
|
|
|
|
Add a "cts-event-workaround" property to Pi DTBs and use the presence
|
|
of that property to force the flag to be enabled in the driver.
|
|
|
|
See: https://github.com/raspberrypi/linux/issues/1280
|
|
|
|
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
|
|
---
|
|
Documentation/devicetree/bindings/serial/pl011.txt | 3 +++
|
|
drivers/tty/serial/amba-pl011.c | 5 +++++
|
|
2 files changed, 8 insertions(+)
|
|
|
|
--- a/Documentation/devicetree/bindings/serial/pl011.txt
|
|
+++ b/Documentation/devicetree/bindings/serial/pl011.txt
|
|
@@ -35,6 +35,9 @@ Optional properties:
|
|
- poll-timeout-ms:
|
|
Poll timeout when auto-poll is set, default
|
|
3000ms.
|
|
+- cts-event-workaround:
|
|
+ Enables the (otherwise vendor-specific) workaround for the
|
|
+ CTS-induced TX lockup.
|
|
|
|
See also bindings/arm/primecell.txt
|
|
|
|
--- a/drivers/tty/serial/amba-pl011.c
|
|
+++ b/drivers/tty/serial/amba-pl011.c
|
|
@@ -2681,6 +2681,11 @@ static int pl011_probe(struct amba_devic
|
|
if (IS_ERR(uap->clk))
|
|
return PTR_ERR(uap->clk);
|
|
|
|
+ if (of_property_read_bool(dev->dev.of_node, "cts-event-workaround")) {
|
|
+ vendor->cts_event_workaround = true;
|
|
+ dev_info(&dev->dev, "cts_event_workaround enabled\n");
|
|
+ }
|
|
+
|
|
uap->reg_offset = vendor->reg_offset;
|
|
uap->vendor = vendor;
|
|
uap->fifosize = vendor->get_fifosize(dev);
|