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-rw-r--r--sys-kernel/boest-v5.0.15/raspberrypi/0034-amba_pl011-Add-cts-event-workaround-DT-property.patch51
1 files changed, 51 insertions, 0 deletions
diff --git a/sys-kernel/boest-v5.0.15/raspberrypi/0034-amba_pl011-Add-cts-event-workaround-DT-property.patch b/sys-kernel/boest-v5.0.15/raspberrypi/0034-amba_pl011-Add-cts-event-workaround-DT-property.patch
new file mode 100644
index 00000000..b4978ab9
--- /dev/null
+++ b/sys-kernel/boest-v5.0.15/raspberrypi/0034-amba_pl011-Add-cts-event-workaround-DT-property.patch
@@ -0,0 +1,51 @@
+From a02fa1bc15f5b5af34e036633834d900fc81ba52 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.org>
+Date: Fri, 29 Sep 2017 10:32:19 +0100
+Subject: [PATCH 034/194] 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(+)
+
+diff --git a/Documentation/devicetree/bindings/serial/pl011.txt b/Documentation/devicetree/bindings/serial/pl011.txt
+index 77863aefe9ef..8d65b0ec2828 100644
+--- 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
+
+diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
+index 39d717e94af3..6f15f32fa194 100644
+--- a/drivers/tty/serial/amba-pl011.c
++++ b/drivers/tty/serial/amba-pl011.c
+@@ -2661,6 +2661,11 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
+ 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);