Merge tag 'tty-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty and serial updates from Greg KH:
 "Here is the big tty and serial patch set for 4.9-rc1.

  It also includes some drivers/dma/ changes, as those were needed by
  some serial drivers, and they were all acked by the DMA maintainer.

  Also in here is the long-suffering ACPI SPCR patchset, which was
  passed around from maintainer to maintainer like a hot-potato. Seems I
  was the sucker^Wlucky one. All of those patches have been acked by the
  various subsystem maintainers as well.

  All of this has been in linux-next with no reported issues"

* tag 'tty-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (111 commits)
  Revert "serial: pl011: add console matching function"
  MAINTAINERS: update entry for atmel_serial driver
  serial: pl011: add console matching function
  ARM64: ACPI: enable ACPI_SPCR_TABLE
  ACPI: parse SPCR and enable matching console
  of/serial: move earlycon early_param handling to serial
  Revert "drivers/tty: Explicitly pass current to show_stack"
  tty: amba-pl011: Don't complain on -EPROBE_DEFER when no irq
  nios2: dts: 10m50: Add tx-threshold parameter
  serial: 8250: Set Altera 16550 TX FIFO Threshold
  serial: 8250: of: Load TX FIFO Threshold from DT
  Documentation: dt: serial: Add TX FIFO threshold parameter
  drivers/tty: Explicitly pass current to show_stack
  serial: imx: Fix DCD reading
  serial: stm32: mark symbols static where possible
  serial: xuartps: Add some register initialisation to cdns_early_console_setup()
  serial: xuartps: Removed unwanted checks while reading the error conditions
  serial: xuartps: Rewrite the interrupt handling logic
  serial: stm32: use mapbase instead of membase for DMA
  tty/serial: atmel: fix fractional baud rate computation
  ...

3 files changed, 54 insertions, 5 deletions

diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
index 936ab5b87324..f86bb06c39e9 100644
--- a/Documentation/devicetree/bindings/serial/8250.txt
+++ b/Documentation/devicetree/bindings/serial/8250.txt
@@ -42,6 +42,8 @@ Optional properties:
 - auto-flow-control: one way to enable automatic flow control support. The
   driver is allowed to detect support for the capability even without this
   property.
+- tx-threshold: Specify the TX FIFO low water indication for parts with
+  programmable TX FIFO thresholds.
 
 Note:
 * fsl,ns16550:
diff --git a/Documentation/devicetree/bindings/serial/st,stm32-usart.txt b/Documentation/devicetree/bindings/serial/st,stm32-usart.txt
new file mode 100644
index 000000000000..85ec5f2b1996
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/st,stm32-usart.txt
@@ -0,0 +1,46 @@
+* STMicroelectronics STM32 USART
+
+Required properties:
+- compatible: Can be either "st,stm32-usart", "st,stm32-uart",
+"st,stm32f7-usart" or "st,stm32f7-uart" depending on whether
+the device supports synchronous mode and is compatible with
+stm32(f4) or stm32f7.
+- reg: The address and length of the peripheral registers space
+- interrupts: The interrupt line of the USART instance
+- clocks: The input clock of the USART instance
+
+Optional properties:
+- pinctrl: The reference on the pins configuration
+- st,hw-flow-ctrl: bool flag to enable hardware flow control.
+- dmas: phandle(s) to DMA controller node(s). Refer to stm32-dma.txt
+- dma-names: "rx" and/or "tx"
+
+Examples:
+usart4: serial@40004c00 {
+	compatible = "st,stm32-uart";
+	reg = <0x40004c00 0x400>;
+	interrupts = <52>;
+	clocks = <&clk_pclk1>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_usart4>;
+};
+
+usart2: serial@40004400 {
+	compatible = "st,stm32-usart", "st,stm32-uart";
+	reg = <0x40004400 0x400>;
+	interrupts = <38>;
+	clocks = <&clk_pclk1>;
+	st,hw-flow-ctrl;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_usart2 &pinctrl_usart2_rtscts>;
+};
+
+usart1: serial@40011000 {
+	compatible = "st,stm32-usart", "st,stm32-uart";
+	reg = <0x40011000 0x400>;
+	interrupts = <37>;
+	clocks = <&rcc 0 164>;
+	dmas = <&dma2 2 4 0x414 0x0>,
+	       <&dma2 7 4 0x414 0x0>;
+	dma-names = "rx", "tx";
+};
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 25037ded3683..0e285941e3c7 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1054,11 +1054,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			determined by the stdout-path property in device
 			tree's chosen node.
 
-		cdns,<addr>
-			Start an early, polled-mode console on a cadence serial
-			port at the specified address. The cadence serial port
-			must already be setup and configured. Options are not
-			yet supported.
+		cdns,<addr>[,options]
+			Start an early, polled-mode console on a Cadence
+			(xuartps) serial port at the specified address. Only
+			supported option is baud rate. If baud rate is not
+			specified, the serial port must already be setup and
+			configured.
 
 		uart[8250],io,<addr>[,options]
 		uart[8250],mmio,<addr>[,options]