[PATCH 0/6] Add initial support for S32V234-EVB

[PATCH 0/6] Add initial support for S32V234-EVB

[Stefan-gabriel Mirea]

Hello,

NXP's S32V234[1] ("Treerunner") vision microprocessors are targeted for
high-performance, computationally intensive vision and sensor fusion
applications that require automotive safety levels. They include leading
edge Camera Vision modules like APEX-2, ISP and GPU. The S32V234-EVB and
S32V234-SBC boards are available for customer evaluation.

The following patch series introduces minimal enablement support for the
NXP S32V234-EVB2[2] board, which leverages most of the SoC capabilities.
The series includes a driver for operating the on-chip LINFlexD controller
in UART mode.

In the future, we aim to submit multiple drivers upstream, which can be
found in the kernel of our Auto Linux BSP[3] ("ALB"), starting with basic
pinmuxing, clock and uSDHC drivers.

For validation, you can use the U-Boot bootloader in the ALB[4], which we
build and test with our patched version of the Linaro GCC 6.3.1 2017.05
toolchain for ARM 64-bit, with sources available on [5].

[1] https://www.nxp.com/products/processors-and-microcontrollers/arm-based-processors-and-mcus/s32-automotive-platform/vision-processor-for-front-and-surround-view-camera-machine-learning-and-sensor-fusion:S32V234
[2] https://www.nxp.com/support/developer-resources/evaluation-and-development-boards/ultra-reliable-dev-platforms/s32v-mpus-platforms/s32v-vision-and-sensor-fusion-evaluation-system:S32V234EVB
[3] https://source.codeaurora.org/external/autobsps32/linux/
[4] https://source.codeaurora.org/external/autobsps32/u-boot/
[5] https://source.codeaurora.org/external/s32ds/compiler/gcc/

Eddy Petrișor (1):
  dt-bindings: arm: fsl: Add the S32V234-EVB board

Mihaela Martinas (2):
  arm64: Introduce config for S32
  arm64: defconfig: Enable configs for S32V234

Stefan-Gabriel Mirea (1):
  tty: serial: Add linflexuart driver for S32V234

Stoica Cosmin-Stefan (2):
  arm64: dts: fsl: Add device tree for S32V234-EVB
  dt-bindings: serial: Document Freescale LINFlex UART

 .../admin-guide/kernel-parameters.txt         |   6 +
 .../devicetree/bindings/arm/fsl.yaml          |   6 +
 .../bindings/serial/fsl,s32-linflexuart.txt   |  24 +
 arch/arm64/Kconfig.platforms                  |   5 +
 arch/arm64/boot/dts/freescale/Makefile        |   2 +
 .../boot/dts/freescale/fsl-s32v234-evb.dts    |  20 +
 .../arm64/boot/dts/freescale/fsl-s32v234.dtsi | 130 +++
 arch/arm64/configs/defconfig                  |   3 +
 drivers/tty/serial/Kconfig                    |  15 +
 drivers/tty/serial/Makefile                   |   1 +
 drivers/tty/serial/fsl_linflexuart.c          | 956 ++++++++++++++++++
 include/uapi/linux/serial_core.h              |   3 +
 12 files changed, 1171 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.txt
 create mode 100644 arch/arm64/boot/dts/freescale/fsl-s32v234-evb.dts
 create mode 100644 arch/arm64/boot/dts/freescale/fsl-s32v234.dtsi
 create mode 100644 drivers/tty/serial/fsl_linflexuart.c

-- 
2.22.0

[PATCH 1/6] dt-bindings: arm: fsl: Add the S32V234-EVB board

[Stefan-gabriel Mirea]

From: Eddy Petrișor <eddy.petrisor@nxp.com>

Add entry for the NXP S32V234 Customer Evaluation Board to the board/SoC
bindings.

Signed-off-by: Eddy Petrișor <eddy.petrisor@nxp.com>
Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
---
 Documentation/devicetree/bindings/arm/fsl.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/fsl.yaml b/Documentation/devicetree/bindings/arm/fsl.yaml
index 7294ac36f4c0..104d60a11177 100644
--- a/Documentation/devicetree/bindings/arm/fsl.yaml
+++ b/Documentation/devicetree/bindings/arm/fsl.yaml
@@ -309,4 +309,10 @@ properties:
               - fsl,ls2088a-rdb
           - const: fsl,ls2088a
 
+      - description: S32V234 Customer Evaluation Board
+        items:
+          - enum:
+              - fsl,s32v234-evb
+          - const: fsl,s32v234
+
 ...
-- 
2.22.0

Re: [PATCH 1/6] dt-bindings: arm: fsl: Add the S32V234-EVB board

[Rob Herring]

On Fri, Aug 2, 2019 at 1:47 PM Stefan-gabriel Mirea
<stefan-gabriel.mirea@nxp.com> wrote:
>
> From: Eddy Petrișor <eddy.petrisor@nxp.com>
>
> Add entry for the NXP S32V234 Customer Evaluation Board to the board/SoC
> bindings.
>
> Signed-off-by: Eddy Petrișor <eddy.petrisor@nxp.com>
> Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
> ---
>  Documentation/devicetree/bindings/arm/fsl.yaml | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/arm/fsl.yaml b/Documentation/devicetree/bindings/arm/fsl.yaml
> index 7294ac36f4c0..104d60a11177 100644
> --- a/Documentation/devicetree/bindings/arm/fsl.yaml
> +++ b/Documentation/devicetree/bindings/arm/fsl.yaml
> @@ -309,4 +309,10 @@ properties:
>                - fsl,ls2088a-rdb
>            - const: fsl,ls2088a
>
> +      - description: S32V234 Customer Evaluation Board

Most of the entries in this file are for all the boards for an SoC.

> +        items:
> +          - enum:
> +              - fsl,s32v234-evb

If that's not going to be the case here, you can use 'const' here.

> +          - const: fsl,s32v234
> +
>  ...
> --
> 2.22.0
>

Re: [EXT] Re: [PATCH 1/6] dt-bindings: arm: fsl: Add the S32V234-EVB board

[Stefan-gabriel Mirea]

Hello Rob,

On 8/3/2019 1:38 AM, Rob Herring wrote:
> On Fri, Aug 2, 2019 at 1:47 PM Stefan-gabriel Mirea
> <stefan-gabriel.mirea@nxp.com> wrote:
>> +      - description: S32V234 Customer Evaluation Board
>
> Most of the entries in this file are for all the boards for an SoC.
>
>> +        items:
>> +          - enum:
>> +              - fsl,s32v234-evb
>
> If that's not going to be the case here, you can use 'const' here.

We also intend to submit patches for the SBC-S32V234[1] board in the
future and I believe that its 'compatible' should share this entry.
Would it therefore be preferable to update the description at this
moment and add a comment, like:

      - description: S32V234 based Boards
        items:
          - enum:
              - fsl,s32v234-evb           # S32V234-EVB2 Customer Evaluation Board
          - const: fsl,s32v234

or just replace the single-value 'enum' with a 'const' for now?

Regards,
Stefan

[1] https://www.nxp.com/design/development-boards/automotive-development-platforms/s32v-mpus-platforms/s32v-vision-and-sensor-fusion-evaluation-board:SBC-S32V234

[PATCH 2/6] arm64: Introduce config for S32

[Stefan-gabriel Mirea]

From: Mihaela Martinas <Mihaela.Martinas@freescale.com>

Add configuration option for the Freescale S32 platform family in
Kconfig.platforms. For starters, the only SoC supported will be Treerunner
(S32V234), with a single execution target: the S32V234-EVB (rev 29288)
board.

Signed-off-by: Mihaela Martinas <Mihaela.Martinas@freescale.com>
Signed-off-by: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>
Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
---
 arch/arm64/Kconfig.platforms | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms
index 4778c775de1b..a9a6152d37eb 100644
--- a/arch/arm64/Kconfig.platforms
+++ b/arch/arm64/Kconfig.platforms
@@ -210,6 +210,11 @@ config ARCH_ROCKCHIP
 	  This enables support for the ARMv8 based Rockchip chipsets,
 	  like the RK3368.
 
+config ARCH_S32
+	bool "Freescale S32 SoC Family"
+	help
+	  This enables support for the Freescale S32 family of processors.
+
 config ARCH_SEATTLE
 	bool "AMD Seattle SoC Family"
 	help
-- 
2.22.0

[PATCH 3/6] arm64: dts: fsl: Add device tree for S32V234-EVB

[Stefan-gabriel Mirea]

From: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>

Add initial version of device tree for S32V234-EVB, including nodes for the
4 Cortex-A53 cores, AIPS bus with UART modules, ARM architected timer and
Generic Interrupt Controller (GIC).

Keep SoC level separate from board level to let future boards with this SoC
share common properties, while the dts files will keep board-dependent
properties.

Signed-off-by: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>
Signed-off-by: Mihaela Martinas <Mihaela.Martinas@freescale.com>
Signed-off-by: Dan Nica <dan.nica@nxp.com>
Signed-off-by: Larisa Grigore <Larisa.Grigore@nxp.com>
Signed-off-by: Phu Luu An <phu.luuan@nxp.com>
Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
---
 arch/arm64/boot/dts/freescale/Makefile        |   2 +
 .../boot/dts/freescale/fsl-s32v234-evb.dts    |  20 +++
 .../arm64/boot/dts/freescale/fsl-s32v234.dtsi | 130 ++++++++++++++++++
 3 files changed, 152 insertions(+)
 create mode 100644 arch/arm64/boot/dts/freescale/fsl-s32v234-evb.dts
 create mode 100644 arch/arm64/boot/dts/freescale/fsl-s32v234.dtsi

diff --git a/arch/arm64/boot/dts/freescale/Makefile b/arch/arm64/boot/dts/freescale/Makefile
index c043aca66572..3af29b58a833 100644
--- a/arch/arm64/boot/dts/freescale/Makefile
+++ b/arch/arm64/boot/dts/freescale/Makefile
@@ -26,3 +26,5 @@ dtb-$(CONFIG_ARCH_MXC) += imx8mq-librem5-devkit.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx8mq-zii-ultra-rmb3.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx8mq-zii-ultra-zest.dtb
 dtb-$(CONFIG_ARCH_MXC) += imx8qxp-mek.dtb
+
+dtb-$(CONFIG_ARCH_S32) += fsl-s32v234-evb.dtb
diff --git a/arch/arm64/boot/dts/freescale/fsl-s32v234-evb.dts b/arch/arm64/boot/dts/freescale/fsl-s32v234-evb.dts
new file mode 100644
index 000000000000..9b3983402998
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/fsl-s32v234-evb.dts
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2015-2016 Freescale Semiconductor, Inc.
+ * Copyright 2016-2017 NXP
+ */
+
+/dts-v1/;
+#include "fsl-s32v234.dtsi"
+
+/ {
+	compatible = "fsl,s32v234-evb", "fsl,s32v234";
+};
+
+&uart0 {
+	status = "okay";
+};
+
+&uart1 {
+	status = "okay";
+};
diff --git a/arch/arm64/boot/dts/freescale/fsl-s32v234.dtsi b/arch/arm64/boot/dts/freescale/fsl-s32v234.dtsi
new file mode 100644
index 000000000000..6d686d3ba997
--- /dev/null
+++ b/arch/arm64/boot/dts/freescale/fsl-s32v234.dtsi
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright 2015-2016 Freescale Semiconductor, Inc.
+ * Copyright 2016-2018 NXP
+ */
+
+/memreserve/ 0x80000000 0x00010000;
+
+/ {
+	model = "Freescale S32V234";
+	compatible = "fsl,s32v234";
+	interrupt-parent = <&gic>;
+	#address-cells = <2>;
+	#size-cells = <2>;
+
+	aliases {
+		serial0 = &uart0;
+		serial1 = &uart1;
+	};
+
+	cpus {
+		#address-cells = <2>;
+		#size-cells = <0>;
+
+		cpu0: cpu@0 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a53";
+			reg = <0x0 0x0>;
+			enable-method = "spin-table";
+			cpu-release-addr = <0x0 0x80000000>;
+			next-level-cache = <&cluster0_l2_cache>;
+		};
+		cpu1: cpu@1 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a53";
+			reg = <0x0 0x1>;
+			enable-method = "spin-table";
+			cpu-release-addr = <0x0 0x80000000>;
+			next-level-cache = <&cluster0_l2_cache>;
+		};
+		cpu2: cpu@100 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a53";
+			reg = <0x0 0x100>;
+			enable-method = "spin-table";
+			cpu-release-addr = <0x0 0x80000000>;
+			next-level-cache = <&cluster1_l2_cache>;
+		};
+		cpu3: cpu@101 {
+			device_type = "cpu";
+			compatible = "arm,cortex-a53";
+			reg = <0x0 0x101>;
+			enable-method = "spin-table";
+			cpu-release-addr = <0x0 0x80000000>;
+			next-level-cache = <&cluster1_l2_cache>;
+		};
+
+		cluster0_l2_cache: l2-cache0 {
+			compatible = "cache";
+		};
+
+		cluster1_l2_cache: l2-cache1 {
+			compatible = "cache";
+		};
+	};
+
+	soc {
+		#address-cells = <2>;
+		#size-cells = <2>;
+		compatible = "simple-bus";
+		interrupt-parent = <&gic>;
+		ranges;
+
+		aips0: aips-bus@40000000 {
+			compatible = "simple-bus";
+			#address-cells = <2>;
+			#size-cells = <2>;
+			interrupt-parent = <&gic>;
+			reg = <0x0 0x40000000 0x0 0x7D000>;
+			ranges;
+
+			uart0: serial@40053000 {
+				compatible = "fsl,s32-linflexuart";
+				reg = <0x0 0x40053000 0x0 0x1000>;
+				interrupts = <0 59 1>;
+				status = "disabled";
+			};
+		};
+
+		aips1: aips-bus@40080000 {
+			compatible = "simple-bus";
+			#address-cells = <2>;
+			#size-cells = <2>;
+			interrupt-parent = <&gic>;
+			reg = <0x0 0x40080000 0x0 0x70000>;
+			ranges;
+
+			uart1: serial@400bc000 {
+				compatible = "fsl,s32-linflexuart";
+				reg = <0x0 0x400bc000 0x0 0x1000>;
+				interrupts = <0 60 1>;
+				status = "disabled";
+			};
+		};
+	};
+
+	timer {
+		compatible = "arm,armv8-timer";
+		interrupts = <1 13 0xf08>,
+			     <1 14 0xf08>,
+			     <1 11 0xf08>,
+			     <1 10 0xf08>;
+		/* clock-frequency might be modified by u-boot, depending on the
+		 * chip version.
+		 */
+		clock-frequency = <10000000>;
+	};
+
+	gic: interrupt-controller@7d001000 {
+		compatible = "arm,cortex-a15-gic", "arm,cortex-a9-gic";
+		#interrupt-cells = <3>;
+		#address-cells = <0>;
+		interrupt-controller;
+		reg = <0 0x7d001000 0 0x1000>,
+		      <0 0x7d002000 0 0x2000>,
+		      <0 0x7d004000 0 0x2000>,
+		      <0 0x7d006000 0 0x2000>;
+		interrupts = <1 9 0xf04>;
+	};
+};
-- 
2.22.0

[PATCH 4/6] dt-bindings: serial: Document Freescale LINFlex UART

[Stefan-gabriel Mirea]

From: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>

Add documentation for the serial communication interface module (LINFlex),
found in two instances on S32V234.

Signed-off-by: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>
Signed-off-by: Larisa Grigore <Larisa.Grigore@nxp.com>
Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
---
 .../bindings/serial/fsl,s32-linflexuart.txt   | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.txt

diff --git a/Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.txt b/Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.txt
new file mode 100644
index 000000000000..957ffeaca9f1
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/fsl,s32-linflexuart.txt
@@ -0,0 +1,24 @@
+* Freescale Linflex UART
+
+The LINFlexD controller implements several LIN protocol versions, as well as
+support for full-duplex UART communication through 8-bit and 9-bit frames. The
+Linflex UART driver enables operation only in UART mode.
+
+See chapter 47 ("LINFlexD") in the reference manual[1].
+
+Required properties:
+- compatible :
+  - "fsl,s32-linflexuart" for linflex configured in uart mode which
+  is compatible with the one integrated on S32V234 SoC
+- reg : Address and length of the register set for the device
+- interrupts : Should contain uart interrupt
+
+Example:
+uart0:serial@40053000 {
+	compatible = "fsl,s32-linflexuart";
+	reg = <0x0 0x40053000 0x0 0x1000>;
+	interrupts = <0 59 4>;
+	status = "disabled";
+};
+
+[1] https://www.nxp.com/webapp/Download?colCode=S32V234RM
-- 
2.22.0

[PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Stefan-gabriel Mirea]

Introduce support for LINFlex driver, based on:
- the version of Freescale LPUART driver after commit b3e3bf2ef2c7 ("Merge
  4.0-rc7 into tty-next");
- commit abf1e0a98083 ("tty: serial: fsl_lpuart: lock port on console
  write").
In this basic version, the driver can be tested using initramfs and relies
on the clocks and pin muxing set up by U-Boot.

Remarks concerning the earlycon support:

- LinFlexD does not allow character transmissions in the INIT mode (see
  section 47.4.2.1 in the reference manual[1]). Therefore, a mutual
  exclusion between the first linflex_setup_watermark/linflex_set_termios
  executions and linflex_earlycon_putchar was employed and the characters
  normally sent to earlycon during initialization are kept in a buffer and
  sent afterwards.

- Empirically, character transmission is also forbidden within the last 1-2
  ms before entering the INIT mode, so we use an explicit timeout
  (PREINIT_DELAY) between linflex_earlycon_putchar and the first call to
  linflex_setup_watermark.

- U-Boot currently uses the UART FIFO mode, while this driver makes the
  transition to the buffer mode. Therefore, the earlycon putchar function
  matches the U-Boot behavior before initializations and the Linux behavior
  after.

[1] https://www.nxp.com/webapp/Download?colCode=S32V234RM

Signed-off-by: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>
Signed-off-by: Adrian.Nitu <adrian.nitu@freescale.com>
Signed-off-by: Larisa Grigore <Larisa.Grigore@nxp.com>
Signed-off-by: Ana Nedelcu <B56683@freescale.com>
Signed-off-by: Mihaela Martinas <Mihaela.Martinas@freescale.com>
Signed-off-by: Matthew Nunez <matthew.nunez@nxp.com>
[stefan-gabriel.mirea@nxp.com: Reduced for upstreaming and implemented
                               earlycon support]
Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
---
 .../admin-guide/kernel-parameters.txt         |   6 +
 drivers/tty/serial/Kconfig                    |  15 +
 drivers/tty/serial/Makefile                   |   1 +
 drivers/tty/serial/fsl_linflexuart.c          | 956 ++++++++++++++++++
 include/uapi/linux/serial_core.h              |   3 +
 5 files changed, 981 insertions(+)
 create mode 100644 drivers/tty/serial/fsl_linflexuart.c

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 46b826fcb5ad..4d545732aadc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1090,6 +1090,12 @@
 			the framebuffer, pass the 'ram' option so that it is
 			mapped with the correct attributes.
 
+		linflex,<addr>
+			Use early console provided by Freescale LinFlex UART
+			serial driver for NXP S32V234 SoCs. A valid base
+			address must be provided, and the serial port must
+			already be setup and configured.
+
 	earlyprintk=	[X86,SH,ARM,M68k,S390]
 			earlyprintk=vga
 			earlyprintk=sclp
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index fd385c8c53a5..b4fa2f7c96bd 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1452,6 +1452,21 @@ config SERIAL_FSL_LPUART_CONSOLE
 	  If you have enabled the lpuart serial port on the Freescale SoCs,
 	  you can make it the console by answering Y to this option.
 
+config SERIAL_FSL_LINFLEXUART
+	tristate "Freescale linflexuart serial port support"
+	select SERIAL_CORE
+	help
+	  Support for the on-chip linflexuart on some Freescale SOCs.
+
+config SERIAL_FSL_LINFLEXUART_CONSOLE
+	bool "Console on Freescale linflexuart serial port"
+	depends on SERIAL_FSL_LINFLEXUART=y
+	select SERIAL_CORE_CONSOLE
+	select SERIAL_EARLYCON
+	help
+	  If you have enabled the linflexuart serial port on the Freescale
+	  SoCs, you can make it the console by answering Y to this option.
+
 config SERIAL_CONEXANT_DIGICOLOR
 	tristate "Conexant Digicolor CX92xxx USART serial port support"
 	depends on OF
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 7cd7cabfa6c4..7a3d52a453b7 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o
 obj-$(CONFIG_SERIAL_ARC)	+= arc_uart.o
 obj-$(CONFIG_SERIAL_RP2)	+= rp2.o
 obj-$(CONFIG_SERIAL_FSL_LPUART)	+= fsl_lpuart.o
+obj-$(CONFIG_SERIAL_FSL_LINFLEXUART)	+= fsl_linflexuart.o
 obj-$(CONFIG_SERIAL_CONEXANT_DIGICOLOR)	+= digicolor-usart.o
 obj-$(CONFIG_SERIAL_MEN_Z135)	+= men_z135_uart.o
 obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
diff --git a/drivers/tty/serial/fsl_linflexuart.c b/drivers/tty/serial/fsl_linflexuart.c
new file mode 100644
index 000000000000..7c4e6872b360
--- /dev/null
+++ b/drivers/tty/serial/fsl_linflexuart.c
@@ -0,0 +1,956 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Freescale linflexuart serial port driver
+ *
+ * Copyright 2012-2016 Freescale Semiconductor, Inc.
+ * Copyright 2017-2018 NXP
+ */
+
+#if defined(CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE) && \
+	defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/console.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/serial_core.h>
+#include <linux/slab.h>
+#include <linux/tty_flip.h>
+#include <linux/delay.h>
+
+/* All registers are 32-bit width */
+
+#define LINCR1	0x0000	/* LIN control register				*/
+#define LINIER	0x0004	/* LIN interrupt enable register		*/
+#define LINSR	0x0008	/* LIN status register				*/
+#define LINESR	0x000C	/* LIN error status register			*/
+#define UARTCR	0x0010	/* UART mode control register			*/
+#define UARTSR	0x0014	/* UART mode status register			*/
+#define LINTCSR	0x0018	/* LIN timeout control status register		*/
+#define LINOCR	0x001C	/* LIN output compare register			*/
+#define LINTOCR	0x0020	/* LIN timeout control register			*/
+#define LINFBRR	0x0024	/* LIN fractional baud rate register		*/
+#define LINIBRR	0x0028	/* LIN integer baud rate register		*/
+#define LINCFR	0x002C	/* LIN checksum field register			*/
+#define LINCR2	0x0030	/* LIN control register 2			*/
+#define BIDR	0x0034	/* Buffer identifier register			*/
+#define BDRL	0x0038	/* Buffer data register least significant	*/
+#define BDRM	0x003C	/* Buffer data register most significant	*/
+#define IFER	0x0040	/* Identifier filter enable register		*/
+#define IFMI	0x0044	/* Identifier filter match index		*/
+#define IFMR	0x0048	/* Identifier filter mode register		*/
+#define GCR	0x004C	/* Global control register			*/
+#define UARTPTO	0x0050	/* UART preset timeout register			*/
+#define UARTCTO	0x0054	/* UART current timeout register		*/
+
+/*
+ * Register field definitions
+ */
+
+#define LINFLEXD_LINCR1_INIT		BIT(0)
+#define LINFLEXD_LINCR1_MME		BIT(4)
+#define LINFLEXD_LINCR1_BF		BIT(7)
+
+#define LINFLEXD_LINSR_LINS_INITMODE	BIT(12)
+#define LINFLEXD_LINSR_LINS_MASK	(0xF << 12)
+
+#define LINFLEXD_LINIER_SZIE		BIT(15)
+#define LINFLEXD_LINIER_OCIE		BIT(14)
+#define LINFLEXD_LINIER_BEIE		BIT(13)
+#define LINFLEXD_LINIER_CEIE		BIT(12)
+#define LINFLEXD_LINIER_HEIE		BIT(11)
+#define LINFLEXD_LINIER_FEIE		BIT(8)
+#define LINFLEXD_LINIER_BOIE		BIT(7)
+#define LINFLEXD_LINIER_LSIE		BIT(6)
+#define LINFLEXD_LINIER_WUIE		BIT(5)
+#define LINFLEXD_LINIER_DBFIE		BIT(4)
+#define LINFLEXD_LINIER_DBEIETOIE	BIT(3)
+#define LINFLEXD_LINIER_DRIE		BIT(2)
+#define LINFLEXD_LINIER_DTIE		BIT(1)
+#define LINFLEXD_LINIER_HRIE		BIT(0)
+
+#define LINFLEXD_UARTCR_OSR_MASK	(0xF << 24)
+#define LINFLEXD_UARTCR_OSR(uartcr)	(((uartcr) \
+					& LINFLEXD_UARTCR_OSR_MASK) >> 24)
+
+#define LINFLEXD_UARTCR_ROSE		BIT(23)
+
+#define LINFLEXD_UARTCR_RFBM		BIT(9)
+#define LINFLEXD_UARTCR_TFBM		BIT(8)
+#define LINFLEXD_UARTCR_WL1		BIT(7)
+#define LINFLEXD_UARTCR_PC1		BIT(6)
+
+#define LINFLEXD_UARTCR_RXEN		BIT(5)
+#define LINFLEXD_UARTCR_TXEN		BIT(4)
+#define LINFLEXD_UARTCR_PC0		BIT(3)
+
+#define LINFLEXD_UARTCR_PCE		BIT(2)
+#define LINFLEXD_UARTCR_WL0		BIT(1)
+#define LINFLEXD_UARTCR_UART		BIT(0)
+
+#define LINFLEXD_UARTSR_SZF		BIT(15)
+#define LINFLEXD_UARTSR_OCF		BIT(14)
+#define LINFLEXD_UARTSR_PE3		BIT(13)
+#define LINFLEXD_UARTSR_PE2		BIT(12)
+#define LINFLEXD_UARTSR_PE1		BIT(11)
+#define LINFLEXD_UARTSR_PE0		BIT(10)
+#define LINFLEXD_UARTSR_RMB		BIT(9)
+#define LINFLEXD_UARTSR_FEF		BIT(8)
+#define LINFLEXD_UARTSR_BOF		BIT(7)
+#define LINFLEXD_UARTSR_RPS		BIT(6)
+#define LINFLEXD_UARTSR_WUF		BIT(5)
+#define LINFLEXD_UARTSR_4		BIT(4)
+
+#define LINFLEXD_UARTSR_TO		BIT(3)
+
+#define LINFLEXD_UARTSR_DRFRFE		BIT(2)
+#define LINFLEXD_UARTSR_DTFTFF		BIT(1)
+#define LINFLEXD_UARTSR_NF		BIT(0)
+#define LINFLEXD_UARTSR_PE		(LINFLEXD_UARTSR_PE0 |\
+					 LINFLEXD_UARTSR_PE1 |\
+					 LINFLEXD_UARTSR_PE2 |\
+					 LINFLEXD_UARTSR_PE3)
+
+#define LINFLEX_LDIV_MULTIPLIER		(16)
+
+#define DRIVER_NAME	"fsl-linflexuart"
+#define DEV_NAME	"ttyLF"
+#define UART_NR		4
+
+#define EARLYCON_BUFFER_INITIAL_CAP	8
+
+#define PREINIT_DELAY			2000 /* us */
+
+static const struct of_device_id linflex_dt_ids[] = {
+	{
+		.compatible = "fsl,s32-linflexuart",
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, linflex_dt_ids);
+
+#ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
+static struct uart_port *earlycon_port;
+static bool linflex_earlycon_same_instance;
+static spinlock_t init_lock;
+static bool during_init;
+
+static struct {
+	char *content;
+	unsigned int len, cap;
+} earlycon_buf;
+#endif
+
+static void linflex_stop_tx(struct uart_port *port)
+{
+	unsigned long ier;
+
+	ier = readl(port->membase + LINIER);
+	ier &= ~(LINFLEXD_LINIER_DTIE);
+	writel(ier, port->membase + LINIER);
+}
+
+static void linflex_stop_rx(struct uart_port *port)
+{
+	unsigned long ier;
+
+	ier = readl(port->membase + LINIER);
+	writel(ier & ~LINFLEXD_LINIER_DRIE, port->membase + LINIER);
+}
+
+static inline void linflex_transmit_buffer(struct uart_port *sport)
+{
+	struct circ_buf *xmit = &sport->state->xmit;
+	unsigned char c;
+	unsigned long status;
+
+	while (!uart_circ_empty(xmit)) {
+		c = xmit->buf[xmit->tail];
+		writeb(c, sport->membase + BDRL);
+
+		/* Waiting for data transmission completed. */
+		while (((status = readl(sport->membase + UARTSR)) &
+					LINFLEXD_UARTSR_DTFTFF) !=
+					LINFLEXD_UARTSR_DTFTFF)
+			;
+
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		sport->icount.tx++;
+
+		writel(status | LINFLEXD_UARTSR_DTFTFF,
+		       sport->membase + UARTSR);
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(sport);
+
+	if (uart_circ_empty(xmit))
+		linflex_stop_tx(sport);
+}
+
+static void linflex_start_tx(struct uart_port *port)
+{
+	unsigned long ier;
+
+	linflex_transmit_buffer(port);
+	ier = readl(port->membase + LINIER);
+	writel(ier | LINFLEXD_LINIER_DTIE, port->membase + LINIER);
+}
+
+static irqreturn_t linflex_txint(int irq, void *dev_id)
+{
+	struct uart_port *sport = dev_id;
+	struct circ_buf *xmit = &sport->state->xmit;
+	unsigned long flags;
+	unsigned long status;
+
+	spin_lock_irqsave(&sport->lock, flags);
+
+	if (sport->x_char) {
+		writeb(sport->x_char, sport->membase + BDRL);
+
+		/* waiting for data transmission completed */
+		while (((status = readl(sport->membase + UARTSR)) &
+			LINFLEXD_UARTSR_DTFTFF) != LINFLEXD_UARTSR_DTFTFF)
+			;
+
+		writel(status | LINFLEXD_UARTSR_DTFTFF,
+		       sport->membase + UARTSR);
+
+		goto out;
+	}
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(sport)) {
+		linflex_stop_tx(sport);
+		goto out;
+	}
+
+	linflex_transmit_buffer(sport);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(sport);
+
+out:
+	spin_unlock_irqrestore(&sport->lock, flags);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t linflex_rxint(int irq, void *dev_id)
+{
+	struct uart_port *sport = dev_id;
+	unsigned int flg;
+	struct tty_port *port = &sport->state->port;
+	unsigned long flags, status;
+	unsigned char rx;
+
+	spin_lock_irqsave(&sport->lock, flags);
+
+	status = readl(sport->membase + UARTSR);
+	while (status & LINFLEXD_UARTSR_RMB) {
+		rx = readb(sport->membase + BDRM);
+		flg = TTY_NORMAL;
+		sport->icount.rx++;
+
+		if (status & (LINFLEXD_UARTSR_BOF | LINFLEXD_UARTSR_SZF |
+			      LINFLEXD_UARTSR_FEF | LINFLEXD_UARTSR_PE)) {
+			if (status & LINFLEXD_UARTSR_SZF)
+				status |= LINFLEXD_UARTSR_SZF;
+			if (status & LINFLEXD_UARTSR_BOF)
+				status |= LINFLEXD_UARTSR_BOF;
+			if (status & LINFLEXD_UARTSR_FEF)
+				status |= LINFLEXD_UARTSR_FEF;
+			if (status & LINFLEXD_UARTSR_PE)
+				status |=  LINFLEXD_UARTSR_PE;
+		}
+
+		writel(status | LINFLEXD_UARTSR_RMB | LINFLEXD_UARTSR_DRFRFE,
+		       sport->membase + UARTSR);
+		status = readl(sport->membase + UARTSR);
+
+		if (uart_handle_sysrq_char(sport, (unsigned char)rx))
+			continue;
+
+#ifdef SUPPORT_SYSRQ
+			sport->sysrq = 0;
+#endif
+		tty_insert_flip_char(port, rx, flg);
+	}
+
+	spin_unlock_irqrestore(&sport->lock, flags);
+
+	tty_flip_buffer_push(port);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t linflex_int(int irq, void *dev_id)
+{
+	struct uart_port *sport = dev_id;
+	unsigned long status;
+
+	status = readl(sport->membase + UARTSR);
+
+	if (status & LINFLEXD_UARTSR_DRFRFE)
+		linflex_rxint(irq, dev_id);
+	if (status & LINFLEXD_UARTSR_DTFTFF)
+		linflex_txint(irq, dev_id);
+
+	return IRQ_HANDLED;
+}
+
+/* return TIOCSER_TEMT when transmitter is not busy */
+static unsigned int linflex_tx_empty(struct uart_port *port)
+{
+	unsigned long status;
+
+	status = readl(port->membase + UARTSR) & LINFLEXD_UARTSR_DTFTFF;
+
+	return status ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int linflex_get_mctrl(struct uart_port *port)
+{
+	return 0;
+}
+
+static void linflex_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+}
+
+static void linflex_break_ctl(struct uart_port *port, int break_state)
+{
+}
+
+static void linflex_setup_watermark(struct uart_port *sport)
+{
+	unsigned long cr, ier, cr1;
+
+	/* Disable transmission/reception */
+	ier = readl(sport->membase + LINIER);
+	ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE);
+	writel(ier, sport->membase + LINIER);
+
+	cr = readl(sport->membase + UARTCR);
+	cr &= ~(LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN);
+	writel(cr, sport->membase + UARTCR);
+
+	/* Enter initialization mode by setting INIT bit */
+
+	/* set the Linflex in master mode and activate by-pass filter */
+	cr1 = LINFLEXD_LINCR1_BF | LINFLEXD_LINCR1_MME
+	      | LINFLEXD_LINCR1_INIT;
+	writel(cr1, sport->membase + LINCR1);
+
+	/* wait for init mode entry */
+	while ((readl(sport->membase + LINSR)
+		& LINFLEXD_LINSR_LINS_MASK)
+		!= LINFLEXD_LINSR_LINS_INITMODE)
+		;
+
+	/*
+	 *	UART = 0x1;		- Linflex working in UART mode
+	 *	TXEN = 0x1;		- Enable transmission of data now
+	 *	RXEn = 0x1;		- Receiver enabled
+	 *	WL0 = 0x1;		- 8 bit data
+	 *	PCE = 0x0;		- No parity
+	 */
+
+	/* set UART bit to allow writing other bits */
+	writel(LINFLEXD_UARTCR_UART, sport->membase + UARTCR);
+
+	cr = (LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN |
+	      LINFLEXD_UARTCR_WL0 | LINFLEXD_UARTCR_UART);
+
+	writel(cr, sport->membase + UARTCR);
+
+	cr1 &= ~(LINFLEXD_LINCR1_INIT);
+
+	writel(cr1, sport->membase + LINCR1);
+
+	ier = readl(sport->membase + LINIER);
+	ier |= LINFLEXD_LINIER_DRIE;
+	ier |= LINFLEXD_LINIER_DTIE;
+
+	writel(ier, sport->membase + LINIER);
+}
+
+static int linflex_startup(struct uart_port *port)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	linflex_setup_watermark(port);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	ret = devm_request_irq(port->dev, port->irq, linflex_int, 0,
+			       DRIVER_NAME, port);
+
+	return ret;
+}
+
+static void linflex_shutdown(struct uart_port *port)
+{
+	unsigned long ier;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	/* disable interrupts */
+	ier = readl(port->membase + LINIER);
+	ier &= ~(LINFLEXD_LINIER_DRIE | LINFLEXD_LINIER_DTIE);
+	writel(ier, port->membase + LINIER);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	devm_free_irq(port->dev, port->irq, port);
+}
+
+static void
+linflex_set_termios(struct uart_port *port, struct ktermios *termios,
+		    struct ktermios *old)
+{
+	unsigned long flags;
+	unsigned long cr, old_cr, cr1;
+	unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
+
+	cr = readl(port->membase + UARTCR);
+	old_cr = cr;
+
+	/* Enter initialization mode by setting INIT bit */
+	cr1 = readl(port->membase + LINCR1);
+	cr1 |= LINFLEXD_LINCR1_INIT;
+	writel(cr1, port->membase + LINCR1);
+
+	/* wait for init mode entry */
+	while ((readl(port->membase + LINSR)
+		& LINFLEXD_LINSR_LINS_MASK)
+		!= LINFLEXD_LINSR_LINS_INITMODE)
+		;
+
+	/*
+	 * only support CS8 and CS7, and for CS7 must enable PE.
+	 * supported mode:
+	 *	- (7,e/o,1)
+	 *	- (8,n,1)
+	 *	- (8,e/o,1)
+	 */
+	/* enter the UART into configuration mode */
+
+	while ((termios->c_cflag & CSIZE) != CS8 &&
+	       (termios->c_cflag & CSIZE) != CS7) {
+		termios->c_cflag &= ~CSIZE;
+		termios->c_cflag |= old_csize;
+		old_csize = CS8;
+	}
+
+	if ((termios->c_cflag & CSIZE) == CS7) {
+		/* Word length: WL1WL0:00 */
+		cr = old_cr & ~LINFLEXD_UARTCR_WL1 & ~LINFLEXD_UARTCR_WL0;
+	}
+
+	if ((termios->c_cflag & CSIZE) == CS8) {
+		/* Word length: WL1WL0:01 */
+		cr = (old_cr | LINFLEXD_UARTCR_WL0) & ~LINFLEXD_UARTCR_WL1;
+	}
+
+	if (termios->c_cflag & CMSPAR) {
+		if ((termios->c_cflag & CSIZE) != CS8) {
+			termios->c_cflag &= ~CSIZE;
+			termios->c_cflag |= CS8;
+		}
+		/* has a space/sticky bit */
+		cr |= LINFLEXD_UARTCR_WL0;
+	}
+
+	if (termios->c_cflag & CSTOPB)
+		termios->c_cflag &= ~CSTOPB;
+
+	/* parity must be enabled when CS7 to match 8-bits format */
+	if ((termios->c_cflag & CSIZE) == CS7)
+		termios->c_cflag |= PARENB;
+
+	if ((termios->c_cflag & PARENB)) {
+		cr |= LINFLEXD_UARTCR_PCE;
+		if (termios->c_cflag & PARODD)
+			cr = (cr | LINFLEXD_UARTCR_PC0) &
+			     (~LINFLEXD_UARTCR_PC1);
+		else
+			cr = cr & (~LINFLEXD_UARTCR_PC1 &
+				   ~LINFLEXD_UARTCR_PC0);
+	} else {
+		cr &= ~LINFLEXD_UARTCR_PCE;
+	}
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	port->read_status_mask = 0;
+
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |=	(LINFLEXD_UARTSR_FEF |
+						 LINFLEXD_UARTSR_PE0 |
+						 LINFLEXD_UARTSR_PE1 |
+						 LINFLEXD_UARTSR_PE2 |
+						 LINFLEXD_UARTSR_PE3);
+	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
+		port->read_status_mask |= LINFLEXD_UARTSR_FEF;
+
+	/* characters to ignore */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= LINFLEXD_UARTSR_PE;
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= LINFLEXD_UARTSR_PE;
+		/*
+		 * if we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= LINFLEXD_UARTSR_BOF;
+	}
+
+	writel(cr, port->membase + UARTCR);
+
+	cr1 &= ~(LINFLEXD_LINCR1_INIT);
+
+	writel(cr1, port->membase + LINCR1);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *linflex_type(struct uart_port *port)
+{
+	return "FSL_LINFLEX";
+}
+
+static void linflex_release_port(struct uart_port *port)
+{
+	/* nothing to do */
+}
+
+static int linflex_request_port(struct uart_port *port)
+{
+	return 0;
+}
+
+/* configure/auto-configure the port */
+static void linflex_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE)
+		port->type = PORT_LINFLEXUART;
+}
+
+static int linflex_verify_port(struct uart_port *port,
+			       struct serial_struct *ser)
+{
+	if ((ser->type != PORT_UNKNOWN && ser->type != PORT_LINFLEXUART) ||
+	    (port->irq != ser->irq) ||
+	    (ser->io_type != UPIO_MEM) ||
+	    (port->iobase != ser->port) ||
+	    (ser->hub6 != 0))
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct uart_ops linflex_pops = {
+	.tx_empty	= linflex_tx_empty,
+	.set_mctrl	= linflex_set_mctrl,
+	.get_mctrl	= linflex_get_mctrl,
+	.stop_tx	= linflex_stop_tx,
+	.start_tx	= linflex_start_tx,
+	.stop_rx	= linflex_stop_rx,
+	.break_ctl	= linflex_break_ctl,
+	.startup	= linflex_startup,
+	.shutdown	= linflex_shutdown,
+	.set_termios	= linflex_set_termios,
+	.type		= linflex_type,
+	.request_port	= linflex_request_port,
+	.release_port	= linflex_release_port,
+	.config_port	= linflex_config_port,
+	.verify_port	= linflex_verify_port,
+};
+
+static struct uart_port *linflex_ports[UART_NR];
+
+#ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
+static void linflex_console_putchar(struct uart_port *port, int ch)
+{
+	unsigned long cr;
+
+	cr = readl(port->membase + UARTCR);
+
+	writeb(ch, port->membase + BDRL);
+
+	if (!(cr & LINFLEXD_UARTCR_TFBM))
+		while ((readl(port->membase + UARTSR) &
+					LINFLEXD_UARTSR_DTFTFF)
+				!= LINFLEXD_UARTSR_DTFTFF)
+			;
+	else
+		while (readl(port->membase + UARTSR) &
+					LINFLEXD_UARTSR_DTFTFF)
+			;
+
+	if (!(cr & LINFLEXD_UARTCR_TFBM)) {
+		writel((readl(port->membase + UARTSR) |
+					LINFLEXD_UARTSR_DTFTFF),
+					port->membase + UARTSR);
+	}
+}
+
+static void linflex_earlycon_putchar(struct uart_port *port, int ch)
+{
+	unsigned long flags;
+	char *ret;
+
+	if (!linflex_earlycon_same_instance) {
+		linflex_console_putchar(port, ch);
+		return;
+	}
+
+	spin_lock_irqsave(&init_lock, flags);
+	if (!during_init)
+		goto outside_init;
+
+	if (earlycon_buf.len >= 1 << CONFIG_LOG_BUF_SHIFT)
+		goto init_release;
+
+	if (!earlycon_buf.cap) {
+		earlycon_buf.content = kmalloc(EARLYCON_BUFFER_INITIAL_CAP,
+					       GFP_ATOMIC);
+		earlycon_buf.cap = earlycon_buf.content ?
+				   EARLYCON_BUFFER_INITIAL_CAP : 0;
+	} else if (earlycon_buf.len == earlycon_buf.cap) {
+		ret = krealloc(earlycon_buf.content, earlycon_buf.cap << 1,
+			       GFP_ATOMIC);
+		if (ret) {
+			earlycon_buf.content = ret;
+			earlycon_buf.cap <<= 1;
+		}
+	}
+
+	if (earlycon_buf.len < earlycon_buf.cap)
+		earlycon_buf.content[earlycon_buf.len++] = ch;
+
+	goto init_release;
+
+outside_init:
+	linflex_console_putchar(port, ch);
+init_release:
+	spin_unlock_irqrestore(&init_lock, flags);
+}
+
+static void linflex_string_write(struct uart_port *sport, const char *s,
+				 unsigned int count)
+{
+	unsigned long cr, ier = 0;
+
+	ier = readl(sport->membase + LINIER);
+	linflex_stop_tx(sport);
+
+	cr = readl(sport->membase + UARTCR);
+	cr |= (LINFLEXD_UARTCR_TXEN);
+	writel(cr, sport->membase + UARTCR);
+
+	uart_console_write(sport, s, count, linflex_console_putchar);
+
+	writel(ier, sport->membase + LINIER);
+}
+
+static void
+linflex_console_write(struct console *co, const char *s, unsigned int count)
+{
+	struct uart_port *sport = linflex_ports[co->index];
+	unsigned long flags;
+	int locked = 1;
+
+	if (sport->sysrq)
+		locked = 0;
+	else if (oops_in_progress)
+		locked = spin_trylock_irqsave(&sport->lock, flags);
+	else
+		spin_lock_irqsave(&sport->lock, flags);
+
+	linflex_string_write(sport, s, count);
+
+	if (locked)
+		spin_unlock_irqrestore(&sport->lock, flags);
+}
+
+/*
+ * if the port was already initialised (eg, by a boot loader),
+ * try to determine the current setup.
+ */
+static void __init
+linflex_console_get_options(struct uart_port *sport, int *parity, int *bits)
+{
+	unsigned long cr;
+
+	cr = readl(sport->membase + UARTCR);
+	cr &= LINFLEXD_UARTCR_RXEN | LINFLEXD_UARTCR_TXEN;
+
+	if (!cr)
+		return;
+
+	/* ok, the port was enabled */
+
+	*parity = 'n';
+	if (cr & LINFLEXD_UARTCR_PCE) {
+		if (cr & LINFLEXD_UARTCR_PC0)
+			*parity = 'o';
+		else
+			*parity = 'e';
+	}
+
+	if ((cr & LINFLEXD_UARTCR_WL0) && ((cr & LINFLEXD_UARTCR_WL1) == 0)) {
+		if (cr & LINFLEXD_UARTCR_PCE)
+			*bits = 9;
+		else
+			*bits = 8;
+	}
+}
+
+static int __init linflex_console_setup(struct console *co, char *options)
+{
+	struct uart_port *sport;
+	int baud = 115200;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+	int ret;
+	int i;
+	unsigned long flags;
+	/*
+	 * check whether an invalid uart number has been specified, and
+	 * if so, search for the first available port that does have
+	 * console support.
+	 */
+	if (co->index == -1 || co->index >= ARRAY_SIZE(linflex_ports))
+		co->index = 0;
+
+	sport = linflex_ports[co->index];
+	if (!sport)
+		return -ENODEV;
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else
+		linflex_console_get_options(sport, &parity, &bits);
+
+	if (earlycon_port && sport->mapbase == earlycon_port->mapbase) {
+		linflex_earlycon_same_instance = true;
+
+		spin_lock_irqsave(&init_lock, flags);
+		during_init = true;
+		spin_unlock_irqrestore(&init_lock, flags);
+
+		/* Workaround for character loss or output of many invalid
+		 * characters, when INIT mode is entered shortly after a
+		 * character has just been printed.
+		 */
+		udelay(PREINIT_DELAY);
+	}
+
+	linflex_setup_watermark(sport);
+
+	ret = uart_set_options(sport, co, baud, parity, bits, flow);
+
+	if (!linflex_earlycon_same_instance)
+		goto done;
+
+	spin_lock_irqsave(&init_lock, flags);
+
+	/* Emptying buffer */
+	if (earlycon_buf.len) {
+		for (i = 0; i < earlycon_buf.len; i++)
+			linflex_console_putchar(earlycon_port,
+				earlycon_buf.content[i]);
+
+		kfree(earlycon_buf.content);
+		earlycon_buf.len = 0;
+	}
+
+	during_init = false;
+	spin_unlock_irqrestore(&init_lock, flags);
+
+done:
+	return ret;
+}
+
+static struct uart_driver linflex_reg;
+static struct console linflex_console = {
+	.name		= DEV_NAME,
+	.write		= linflex_console_write,
+	.device		= uart_console_device,
+	.setup		= linflex_console_setup,
+	.flags		= CON_PRINTBUFFER,
+	.index		= -1,
+	.data		= &linflex_reg,
+};
+
+static void linflex_earlycon_write(struct console *con, const char *s,
+				   unsigned int n)
+{
+	struct earlycon_device *dev = con->data;
+
+	uart_console_write(&dev->port, s, n, linflex_earlycon_putchar);
+}
+
+static int __init linflex_early_console_setup(struct earlycon_device *device,
+					      const char *options)
+{
+	if (!device->port.membase)
+		return -ENODEV;
+
+	device->con->write = linflex_earlycon_write;
+	earlycon_port = &device->port;
+
+	return 0;
+}
+
+OF_EARLYCON_DECLARE(linflex, "fsl,s32v234-linflexuart",
+		    linflex_early_console_setup);
+
+#define LINFLEX_CONSOLE	(&linflex_console)
+#else
+#define LINFLEX_CONSOLE	NULL
+#endif
+
+static struct uart_driver linflex_reg = {
+	.owner		= THIS_MODULE,
+	.driver_name	= DRIVER_NAME,
+	.dev_name	= DEV_NAME,
+	.nr		= ARRAY_SIZE(linflex_ports),
+	.cons		= LINFLEX_CONSOLE,
+};
+
+static int linflex_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct uart_port *sport;
+	struct resource *res;
+	int ret;
+
+	sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
+	if (!sport)
+		return -ENOMEM;
+
+	ret = of_alias_get_id(np, "serial");
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
+		return ret;
+	}
+	if (ret >= UART_NR) {
+		dev_err(&pdev->dev, "driver limited to %d serial ports\n",
+			UART_NR);
+		return -ENOMEM;
+	}
+
+	sport->line = ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	sport->mapbase = res->start;
+	sport->membase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sport->membase))
+		return PTR_ERR(sport->membase);
+
+	sport->dev = &pdev->dev;
+	sport->type = PORT_LINFLEXUART;
+	sport->iotype = UPIO_MEM;
+	sport->irq = platform_get_irq(pdev, 0);
+	sport->ops = &linflex_pops;
+	sport->flags = UPF_BOOT_AUTOCONF;
+
+	linflex_ports[sport->line] = sport;
+
+	platform_set_drvdata(pdev, sport);
+
+	ret = uart_add_one_port(&linflex_reg, sport);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int linflex_remove(struct platform_device *pdev)
+{
+	struct uart_port *sport = platform_get_drvdata(pdev);
+
+	uart_remove_one_port(&linflex_reg, sport);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int linflex_suspend(struct device *dev)
+{
+	struct uart_port *sport = dev_get_drvdata(dev);
+
+	uart_suspend_port(&linflex_reg, sport);
+
+	return 0;
+}
+
+static int linflex_resume(struct device *dev)
+{
+	struct uart_port *sport = dev_get_drvdata(dev);
+
+	uart_resume_port(&linflex_reg, sport);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(linflex_pm_ops, linflex_suspend, linflex_resume);
+
+static struct platform_driver linflex_driver = {
+	.probe		= linflex_probe,
+	.remove		= linflex_remove,
+	.driver		= {
+		.name	= DRIVER_NAME,
+		.owner	= THIS_MODULE,
+		.of_match_table	= linflex_dt_ids,
+		.pm	= &linflex_pm_ops,
+	},
+};
+
+static int __init linflex_serial_init(void)
+{
+	int ret;
+
+	ret = uart_register_driver(&linflex_reg);
+	if (ret)
+		return ret;
+
+	ret = platform_driver_register(&linflex_driver);
+	if (ret)
+		uart_unregister_driver(&linflex_reg);
+
+#ifdef CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE
+	spin_lock_init(&init_lock);
+#endif
+
+	return ret;
+}
+
+static void __exit linflex_serial_exit(void)
+{
+	platform_driver_unregister(&linflex_driver);
+	uart_unregister_driver(&linflex_reg);
+}
+
+module_init(linflex_serial_init);
+module_exit(linflex_serial_exit);
+
+MODULE_DESCRIPTION("Freescale linflex serial port driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index 5642c05e0da0..25a3dead4473 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -293,4 +293,7 @@
 /* SiFive UART */
 #define PORT_SIFIVE_V0	120
 
+/* Freescale Linflex UART */
+#define PORT_LINFLEXUART	121
+
 #endif /* _UAPILINUX_SERIAL_CORE_H */
-- 
2.22.0

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[gregkh]

On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
> --- a/include/uapi/linux/serial_core.h
> +++ b/include/uapi/linux/serial_core.h
> @@ -293,4 +293,7 @@
>  /* SiFive UART */
>  #define PORT_SIFIVE_V0	120
>  
> +/* Freescale Linflex UART */
> +#define PORT_LINFLEXUART	121

Do you really need this modified?

thanks,

greg k-h

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Stefan-gabriel Mirea]

On 8/5/2019 6:31 PM, gregkh@linuxfoundation.org wrote:
> On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
>>
>> +/* Freescale Linflex UART */
>> +#define PORT_LINFLEXUART     121
> 
> Do you really need this modified?

Hello Greg,

This macro is meant to be assigned to port->type in the config_port
method from uart_ops, in order for verify_port to know if the received
serial_struct structure was really targeted for a LINFlex port. It
needs to be defined outside, to avoid "collisions" with other drivers.

As far as I see, uart_set_info() will actually fail at the
"baud_base < 9600" check[1], right after calling verify_port(), when
performing an ioctl() on "/dev/console" with TIOCSSERIAL using a
serial_struct obtained with TIOCGSERIAL. This happens because this
reduced version of the LINFlex UART driver will not touch the uartclk
field of the uart_port (as there is currently no clock support).
Therefore, the linflex_config/verify_port() functions, along with the
PORT_LINFLEXUART macro, may be indeed unnecessary at this point (and
should be added later). Is this what you mean?

Other than that, I do not see anything wrong with the addition of a
define in serial_core.h for this purpose (which is also what most of the
serial drivers do, including amba-pl011.c, mentioned in
Documentation/driver-api/serial/driver.rst as providing the reference
implementation), so please be more specific.

Regards,
Stefan

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tty/serial/serial_core.c?h=v5.3-rc1#n872

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[gregkh]

On Tue, Aug 06, 2019 at 05:11:17PM +0000, Stefan-gabriel Mirea wrote:
> On 8/5/2019 6:31 PM, gregkh@linuxfoundation.org wrote:
> > On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
> >>
> >> +/* Freescale Linflex UART */
> >> +#define PORT_LINFLEXUART     121
> > 
> > Do you really need this modified?
> 
> Hello Greg,
> 
> This macro is meant to be assigned to port->type in the config_port
> method from uart_ops, in order for verify_port to know if the received
> serial_struct structure was really targeted for a LINFlex port. It
> needs to be defined outside, to avoid "collisions" with other drivers.

Yes, I know what it goes to, but does anyone in userspace actually use
it?

> As far as I see, uart_set_info() will actually fail at the
> "baud_base < 9600" check[1], right after calling verify_port(), when
> performing an ioctl() on "/dev/console" with TIOCSSERIAL using a
> serial_struct obtained with TIOCGSERIAL. This happens because this
> reduced version of the LINFlex UART driver will not touch the uartclk
> field of the uart_port (as there is currently no clock support).
> Therefore, the linflex_config/verify_port() functions, along with the
> PORT_LINFLEXUART macro, may be indeed unnecessary at this point (and
> should be added later). Is this what you mean?

No, see below.

> Other than that, I do not see anything wrong with the addition of a
> define in serial_core.h for this purpose (which is also what most of the
> serial drivers do, including amba-pl011.c, mentioned in
> Documentation/driver-api/serial/driver.rst as providing the reference
> implementation), so please be more specific.

I am getting tired of dealing with merge issues with that list, and no
one seems to be able to find where they are really needed for userspace,
especially for new devices.  What happens if you do not have use it?

thanks,

greg k-h

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Stefan-gabriel Mirea]

On 8/6/2019 9:40 PM, gregkh@linuxfoundation.org wrote:
> On Tue, Aug 06, 2019 at 05:11:17PM +0000, Stefan-gabriel Mirea wrote:
>> On 8/5/2019 6:31 PM, gregkh@linuxfoundation.org wrote:
>>> On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
>>>>
>>>> +/* Freescale Linflex UART */
>>>> +#define PORT_LINFLEXUART     121
>>>
>>> Do you really need this modified?
>>
>> Hello Greg,
>>
>> This macro is meant to be assigned to port->type in the config_port
>> method from uart_ops, in order for verify_port to know if the received
>> serial_struct structure was really targeted for a LINFlex port. It
>> needs to be defined outside, to avoid "collisions" with other drivers.
> 
> Yes, I know what it goes to, but does anyone in userspace actually use
> it?

No, we do not use it from userspace, but kept the pattern only for
conformance.

>> Other than that, I do not see anything wrong with the addition of a
>> define in serial_core.h for this purpose (which is also what most of the
>> serial drivers do, including amba-pl011.c, mentioned in
>> Documentation/driver-api/serial/driver.rst as providing the reference
>> implementation), so please be more specific.
> 
> I am getting tired of dealing with merge issues with that list, and no
> one seems to be able to find where they are really needed for userspace,
> especially for new devices.  What happens if you do not have use it?

I see. If I drop its usage completely and leave 'type' from the
uart_port as 0, uart_port_startup() will fail when finding that
uport->type == PORT_UNKNOWN at [1] (there may be other effects as well,
e.g. due to the check in uart_configure_port[2]).

So I suppose that I need to define some nonzero 'PORT_KNOWN' macro in
the driver and use that one internally for 'type'. Is my understanding
correct? Will there be any problems if I define it to a positive integer
which is already assigned to another driver, according to serial_core.h?

Regards,
Stefan

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tty/serial/serial_core.c?h=v5.3-rc1#n188
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tty/serial/serial_core.c?h=v5.3-rc1#n2348

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[gregkh]

On Wed, Aug 07, 2019 at 04:42:17PM +0000, Stefan-gabriel Mirea wrote:
> On 8/6/2019 9:40 PM, gregkh@linuxfoundation.org wrote:
> > On Tue, Aug 06, 2019 at 05:11:17PM +0000, Stefan-gabriel Mirea wrote:
> >> On 8/5/2019 6:31 PM, gregkh@linuxfoundation.org wrote:
> >>> On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
> >>>>
> >>>> +/* Freescale Linflex UART */
> >>>> +#define PORT_LINFLEXUART     121
> >>>
> >>> Do you really need this modified?
> >>
> >> Hello Greg,
> >>
> >> This macro is meant to be assigned to port->type in the config_port
> >> method from uart_ops, in order for verify_port to know if the received
> >> serial_struct structure was really targeted for a LINFlex port. It
> >> needs to be defined outside, to avoid "collisions" with other drivers.
> > 
> > Yes, I know what it goes to, but does anyone in userspace actually use
> > it?
> 
> No, we do not use it from userspace, but kept the pattern only for
> conformance.
> 
> >> Other than that, I do not see anything wrong with the addition of a
> >> define in serial_core.h for this purpose (which is also what most of the
> >> serial drivers do, including amba-pl011.c, mentioned in
> >> Documentation/driver-api/serial/driver.rst as providing the reference
> >> implementation), so please be more specific.
> > 
> > I am getting tired of dealing with merge issues with that list, and no
> > one seems to be able to find where they are really needed for userspace,
> > especially for new devices.  What happens if you do not have use it?
> 
> I see. If I drop its usage completely and leave 'type' from the
> uart_port as 0, uart_port_startup() will fail when finding that
> uport->type == PORT_UNKNOWN at [1] (there may be other effects as well,
> e.g. due to the check in uart_configure_port[2]).
> 
> So I suppose that I need to define some nonzero 'PORT_KNOWN' macro in
> the driver and use that one internally for 'type'. Is my understanding
> correct? Will there be any problems if I define it to a positive integer
> which is already assigned to another driver, according to serial_core.h?

Ugh, ok, that's messy, nevermind.  Keep the #define in there, I will try
to figure out how to move all of these at once sometime in the future...

sorry for the noise.

greg k-h

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Stefan-gabriel Mirea]

On 8/7/2019 7:56 PM, gregkh@linuxfoundation.org wrote:
> On Wed, Aug 07, 2019 at 04:42:17PM +0000, Stefan-gabriel Mirea wrote:
>> On 8/6/2019 9:40 PM, gregkh@linuxfoundation.org wrote:
>>> On Tue, Aug 06, 2019 at 05:11:17PM +0000, Stefan-gabriel Mirea wrote:

<snip>

>>>> Other than that, I do not see anything wrong with the addition of a
>>>> define in serial_core.h for this purpose (which is also what most of the
>>>> serial drivers do, including amba-pl011.c, mentioned in
>>>> Documentation/driver-api/serial/driver.rst as providing the reference
>>>> implementation), so please be more specific.
>>>
>>> I am getting tired of dealing with merge issues with that list, and no
>>> one seems to be able to find where they are really needed for userspace,
>>> especially for new devices.  What happens if you do not have use it?
>>
>> I see. If I drop its usage completely and leave 'type' from the
>> uart_port as 0, uart_port_startup() will fail when finding that
>> uport->type == PORT_UNKNOWN at [1] (there may be other effects as well,
>> e.g. due to the check in uart_configure_port[2]).
>>
>> So I suppose that I need to define some nonzero 'PORT_KNOWN' macro in
>> the driver and use that one internally for 'type'. Is my understanding
>> correct? Will there be any problems if I define it to a positive integer
>> which is already assigned to another driver, according to serial_core.h?
> 
> Ugh, ok, that's messy, nevermind.  Keep the #define in there, I will try
> to figure out how to move all of these at once sometime in the future...
> 
> sorry for the noise.

No problem, thank you for your time.

Regards,
Stefan

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Will Deacon]

On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
> Introduce support for LINFlex driver, based on:
> - the version of Freescale LPUART driver after commit b3e3bf2ef2c7 ("Merge
>   4.0-rc7 into tty-next");
> - commit abf1e0a98083 ("tty: serial: fsl_lpuart: lock port on console
>   write").
> In this basic version, the driver can be tested using initramfs and relies
> on the clocks and pin muxing set up by U-Boot.
> 
> Remarks concerning the earlycon support:
> 
> - LinFlexD does not allow character transmissions in the INIT mode (see
>   section 47.4.2.1 in the reference manual[1]). Therefore, a mutual
>   exclusion between the first linflex_setup_watermark/linflex_set_termios
>   executions and linflex_earlycon_putchar was employed and the characters
>   normally sent to earlycon during initialization are kept in a buffer and
>   sent afterwards.
> 
> - Empirically, character transmission is also forbidden within the last 1-2
>   ms before entering the INIT mode, so we use an explicit timeout
>   (PREINIT_DELAY) between linflex_earlycon_putchar and the first call to
>   linflex_setup_watermark.
> 
> - U-Boot currently uses the UART FIFO mode, while this driver makes the
>   transition to the buffer mode. Therefore, the earlycon putchar function
>   matches the U-Boot behavior before initializations and the Linux behavior
>   after.
> 
> [1] https://www.nxp.com/webapp/Download?colCode=S32V234RM
> 
> Signed-off-by: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>
> Signed-off-by: Adrian.Nitu <adrian.nitu@freescale.com>
> Signed-off-by: Larisa Grigore <Larisa.Grigore@nxp.com>
> Signed-off-by: Ana Nedelcu <B56683@freescale.com>
> Signed-off-by: Mihaela Martinas <Mihaela.Martinas@freescale.com>
> Signed-off-by: Matthew Nunez <matthew.nunez@nxp.com>
> [stefan-gabriel.mirea@nxp.com: Reduced for upstreaming and implemented
>                                earlycon support]
> Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
> ---
>  .../admin-guide/kernel-parameters.txt         |   6 +
>  drivers/tty/serial/Kconfig                    |  15 +
>  drivers/tty/serial/Makefile                   |   1 +
>  drivers/tty/serial/fsl_linflexuart.c          | 956 ++++++++++++++++++
>  include/uapi/linux/serial_core.h              |   3 +
>  5 files changed, 981 insertions(+)
>  create mode 100644 drivers/tty/serial/fsl_linflexuart.c
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 46b826fcb5ad..4d545732aadc 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1090,6 +1090,12 @@
>  			the framebuffer, pass the 'ram' option so that it is
>  			mapped with the correct attributes.
>  
> +		linflex,<addr>
> +			Use early console provided by Freescale LinFlex UART
> +			serial driver for NXP S32V234 SoCs. A valid base
> +			address must be provided, and the serial port must
> +			already be setup and configured.

Why isn't earlycon= sufficient for this?

Will

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Stefan-gabriel Mirea]

Hello Will,

On 8/8/2019 11:08 AM, Will Deacon wrote:
> On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
>> +             linflex,<addr>
>> +                     Use early console provided by Freescale LinFlex UART
>> +                     serial driver for NXP S32V234 SoCs. A valid base
>> +                     address must be provided, and the serial port must
>> +                     already be setup and configured.
> 
> Why isn't earlycon= sufficient for this?

"earlycon=" is not actually supported. I will fix this in the next
version by adding a /chosen/stdout-path to the dts. The compatible
string provided to OF_EARLYCON_DECLARE will also be changed from
"fsl,s32v234-linflexuart" to "fsl,s32-linflexuart" to match the one in
the device tree nodes. I missed this after importing a rename from our
codebase.

Should I remove this addition from kernel-parameters.txt after that?

Regards,
Stefan

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Will Deacon]

Hi,

On Thu, Aug 08, 2019 at 12:47:00PM +0000, Stefan-gabriel Mirea wrote:
> On 8/8/2019 11:08 AM, Will Deacon wrote:
> > On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
> >> +             linflex,<addr>
> >> +                     Use early console provided by Freescale LinFlex UART
> >> +                     serial driver for NXP S32V234 SoCs. A valid base
> >> +                     address must be provided, and the serial port must
> >> +                     already be setup and configured.
> > 
> > Why isn't earlycon= sufficient for this?
> 
> "earlycon=" is not actually supported. I will fix this in the next
> version by adding a /chosen/stdout-path to the dts. The compatible
> string provided to OF_EARLYCON_DECLARE will also be changed from
> "fsl,s32v234-linflexuart" to "fsl,s32-linflexuart" to match the one in
> the device tree nodes. I missed this after importing a rename from our
> codebase.
> 
> Should I remove this addition from kernel-parameters.txt after that?

Yes, if you can use earlycon instead, then you can drop your custom option
entirely and therefore there's no need to document it either.

Will

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Stefan-gabriel Mirea]

On 8/8/2019 8:17 PM, Will Deacon wrote:
> On Thu, Aug 08, 2019 at 12:47:00PM +0000, Stefan-gabriel Mirea wrote:
>> On 8/8/2019 11:08 AM, Will Deacon wrote:
>>> On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
>>>> +             linflex,<addr>
>>>> +                     Use early console provided by Freescale LinFlex UART
>>>> +                     serial driver for NXP S32V234 SoCs. A valid base
>>>> +                     address must be provided, and the serial port must
>>>> +                     already be setup and configured.
>>>
>>> Why isn't earlycon= sufficient for this?
>>
>> "earlycon=" is not actually supported. I will fix this in the next
>> version by adding a /chosen/stdout-path to the dts. The compatible
>> string provided to OF_EARLYCON_DECLARE will also be changed from
>> "fsl,s32v234-linflexuart" to "fsl,s32-linflexuart" to match the one in
>> the device tree nodes. I missed this after importing a rename from our
>> codebase.
>>
>> Should I remove this addition from kernel-parameters.txt after that?
> 
> Yes, if you can use earlycon instead, then you can drop your custom option
> entirely and therefore there's no need to document it either.

Can you please clarify what you mean by "drop your custom option"? The
"linflex" option documented in the paragraph is the name of the
earlycon_id declared via "OF_EARLYCON_DECLARE(linflex, ...)". We have
not done anything particular to accept it in the parameter value.

We do use earlycon (e.g. "earlycon=linflex,0x40053000"), we just do not
support an empty value after "=", which needs to be fixed as I
understand, because it does not respect the comment[1] about ARM64.

Regards,
Stefan

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide/kernel-parameters.txt?h=v5.3-rc3#n980

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Will Deacon]

On Fri, Aug 09, 2019 at 09:45:40AM +0000, Stefan-gabriel Mirea wrote:
> On 8/8/2019 8:17 PM, Will Deacon wrote:
> > On Thu, Aug 08, 2019 at 12:47:00PM +0000, Stefan-gabriel Mirea wrote:
> >> On 8/8/2019 11:08 AM, Will Deacon wrote:
> >>> On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
> >>>> +             linflex,<addr>
> >>>> +                     Use early console provided by Freescale LinFlex UART
> >>>> +                     serial driver for NXP S32V234 SoCs. A valid base
> >>>> +                     address must be provided, and the serial port must
> >>>> +                     already be setup and configured.
> >>>
> >>> Why isn't earlycon= sufficient for this?
> >>
> >> "earlycon=" is not actually supported. I will fix this in the next
> >> version by adding a /chosen/stdout-path to the dts. The compatible
> >> string provided to OF_EARLYCON_DECLARE will also be changed from
> >> "fsl,s32v234-linflexuart" to "fsl,s32-linflexuart" to match the one in
> >> the device tree nodes. I missed this after importing a rename from our
> >> codebase.
> >>
> >> Should I remove this addition from kernel-parameters.txt after that?
> > 
> > Yes, if you can use earlycon instead, then you can drop your custom option
> > entirely and therefore there's no need to document it either.
> 
> Can you please clarify what you mean by "drop your custom option"? The
> "linflex" option documented in the paragraph is the name of the
> earlycon_id declared via "OF_EARLYCON_DECLARE(linflex, ...)". We have
> not done anything particular to accept it in the parameter value.

My apologies, I completely misread your patch and thought your were adding
a *new* kernel parameter. Having looked at the context, I now see you're
adding a new earlycon option, which is what I was suggesting :)

By all means, please update the stdout-path, because then you can just pass
"earlycon" and things will work as expected.

Will

Re: [PATCH 5/6] tty: serial: Add linflexuart driver for S32V234

[Stefan-gabriel Mirea]

On 8/9/2019 12:53 PM, Will Deacon wrote:
> On Fri, Aug 09, 2019 at 09:45:40AM +0000, Stefan-gabriel Mirea wrote:
>> On 8/8/2019 8:17 PM, Will Deacon wrote:
>>> On Thu, Aug 08, 2019 at 12:47:00PM +0000, Stefan-gabriel Mirea wrote:
>>>> On 8/8/2019 11:08 AM, Will Deacon wrote:
>>>>> On Fri, Aug 02, 2019 at 07:47:23PM +0000, Stefan-gabriel Mirea wrote:
>>>>>> +             linflex,<addr>
>>>>>> +                     Use early console provided by Freescale LinFlex UART
>>>>>> +                     serial driver for NXP S32V234 SoCs. A valid base
>>>>>> +                     address must be provided, and the serial port must
>>>>>> +                     already be setup and configured.
>>>>>
>>>>> Why isn't earlycon= sufficient for this?
>>>>
>>>> "earlycon=" is not actually supported. I will fix this in the next
>>>> version by adding a /chosen/stdout-path to the dts. The compatible
>>>> string provided to OF_EARLYCON_DECLARE will also be changed from
>>>> "fsl,s32v234-linflexuart" to "fsl,s32-linflexuart" to match the one in
>>>> the device tree nodes. I missed this after importing a rename from our
>>>> codebase.
>>>>
>>>> Should I remove this addition from kernel-parameters.txt after that?
>>>
>>> Yes, if you can use earlycon instead, then you can drop your custom option
>>> entirely and therefore there's no need to document it either.
>>
>> Can you please clarify what you mean by "drop your custom option"? The
>> "linflex" option documented in the paragraph is the name of the
>> earlycon_id declared via "OF_EARLYCON_DECLARE(linflex, ...)". We have
>> not done anything particular to accept it in the parameter value.
> 
> My apologies, I completely misread your patch and thought your were adding
> a *new* kernel parameter. Having looked at the context, I now see you're
> adding a new earlycon option, which is what I was suggesting :)
> 
> By all means, please update the stdout-path, because then you can just pass
> "earlycon" and things will work as expected.

No problem, I will submit the new version soon. Thank you!

Regards,
Stefan

[PATCH 6/6] arm64: defconfig: Enable configs for S32V234

[Stefan-gabriel Mirea]

From: Mihaela Martinas <Mihaela.Martinas@freescale.com>

Enable support for the S32V234 SoC, including the previously added UART
driver.

Signed-off-by: Mihaela Martinas <Mihaela.Martinas@freescale.com>
Signed-off-by: Adrian.Nitu <adrian.nitu@freescale.com>
Signed-off-by: Stoica Cosmin-Stefan <cosmin.stoica@nxp.com>
Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
---
 arch/arm64/configs/defconfig | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 0e58ef02880c..bb5aa95a8455 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -48,6 +48,7 @@ CONFIG_ARCH_MXC=y
 CONFIG_ARCH_QCOM=y
 CONFIG_ARCH_RENESAS=y
 CONFIG_ARCH_ROCKCHIP=y
+CONFIG_ARCH_S32=y
 CONFIG_ARCH_SEATTLE=y
 CONFIG_ARCH_STRATIX10=y
 CONFIG_ARCH_SYNQUACER=y
@@ -347,6 +348,8 @@ CONFIG_SERIAL_XILINX_PS_UART=y
 CONFIG_SERIAL_XILINX_PS_UART_CONSOLE=y
 CONFIG_SERIAL_FSL_LPUART=y
 CONFIG_SERIAL_FSL_LPUART_CONSOLE=y
+CONFIG_SERIAL_FSL_LINFLEXUART=y
+CONFIG_SERIAL_FSL_LINFLEXUART_CONSOLE=y
 CONFIG_SERIAL_MVEBU_UART=y
 CONFIG_SERIAL_DEV_BUS=y
 CONFIG_VIRTIO_CONSOLE=y
-- 
2.22.0