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authorÁlvaro Fernández Rojas <noltari@gmail.com>2020-02-29 09:25:20 +0100
committerÁlvaro Fernández Rojas <noltari@gmail.com>2020-02-29 12:50:51 +0100
commita1383655cfaa71609d6236ae0fcf3b6047462b98 (patch)
treec6f123859e0dfcfaa6c1063eda26f27e208d3cac /target/linux/bcm27xx/patches-5.4/950-0034-amba_pl011-Add-cts-event-workaround-DT-property.patch
parenta8aa974a9dfb4cba484dc4c1e4207fd9ec803410 (diff)
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bcm27xx: add linux 5.4 support
Tested on bcm2710 (Raspberry Pi 3B). Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0034-amba_pl011-Add-cts-event-workaround-DT-property.patch')
-rw-r--r--target/linux/bcm27xx/patches-5.4/950-0034-amba_pl011-Add-cts-event-workaround-DT-property.patch50
1 files changed, 50 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0034-amba_pl011-Add-cts-event-workaround-DT-property.patch b/target/linux/bcm27xx/patches-5.4/950-0034-amba_pl011-Add-cts-event-workaround-DT-property.patch
new file mode 100644
index 0000000000..efa24ac9e9
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.4/950-0034-amba_pl011-Add-cts-event-workaround-DT-property.patch
@@ -0,0 +1,50 @@
+From 2cb280484c8dde281972690cd67299005a796485 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: 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.yaml | 6 ++++++
+ drivers/tty/serial/amba-pl011.c | 5 +++++
+ 2 files changed, 11 insertions(+)
+
+--- a/Documentation/devicetree/bindings/serial/pl011.yaml
++++ b/Documentation/devicetree/bindings/serial/pl011.yaml
+@@ -100,6 +100,12 @@ properties:
+ - $ref: /schemas/types.yaml#/definitions/uint32
+ - default: 3000
+
++ cts-event-workaround:
++ description:
++ Enables the (otherwise vendor-specific) workaround for the
++ CTS-induced TX lockup.
++ type: boolean
++
+ required:
+ - compatible
+ - reg
+--- a/drivers/tty/serial/amba-pl011.c
++++ b/drivers/tty/serial/amba-pl011.c
+@@ -2659,6 +2659,11 @@ 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);