[RFC 0/4] riscv: add initial LiteX SoC support

[RFC 0/4] riscv: add initial LiteX SoC support

[Antony Pavlov]

This RFC patchseries adds initial LiteX RISC-V SoC support for barebox.

You can obtain this patchseries from github:

    $ git clone -b 20190602.litex https://github.com/frantony/barebox

LiteX is a Migen-based System on Chip [1], supporting softcore VexRiscv CPU,
 a 32-bits Linux Capable RISC-V CPU [2].

All the components used to create the LiteX SoC are open-source and
the flexibility of Spinal HDL/Migen allow targeting easily very various
FPGA devices/boards: Lattice, Altera, Xilinx, Microsemi FPGAs
with SDRAM/DDR/DDR2/DDR3/DDR4 RAMs, RMII/MII/RGMII/1000BASE-X Ethernet PHYs.

The LiteX SoC with VexRiscv CPU can be deployed on e.g. Digilent ARTY board [3]
or Terasic DE0-Nano board [4].

You can boot barebox from serial port using flterm [5]:, e.g.:

flterm --port /dev/ttyUSB0 --kernel <path_to_barebox.bin> --kernel-adr 0x40000000


TODO
====

  * add pbl support for riscv barebox;
  * add liteeth Ethernet core support [6] (tip: use ARTY board);
  * fix issues (see the WIP commit);
  * use barebox to start linux [2] and zephyr [7].


REFERENCES
==========

 [1] https://github.com/enjoy-digital/litex
 [2] https://github.com/enjoy-digital/linux-on-litex-vexriscv
 [3] https://store.digilentinc.com/arty-a7-artix-7-fpga-development-board-for-makers-and-hobbyists/
 [4] http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&No=593
 [5] https://github.com/timvideos/flterm
 [6] https://github.com/enjoy-digital/liteeth
 [7] https://github.com/zephyrproject-rtos/zephyr/tree/master/boards/riscv32/litex_vexriscv


Antony Pavlov (4):
  riscv: add initial LiteX SoC support
  serial: add litex UART driver
  WIP: make it work on litex
  riscv: add litex_defconfig

 arch/riscv/Kconfig                            |   6 +
 arch/riscv/Makefile                           |   1 +
 arch/riscv/boot/start.S                       |   2 -
 arch/riscv/configs/litex_defconfig            |  45 +++++++
 arch/riscv/dts/litex-generic.dts              |  17 +++
 arch/riscv/dts/litex.dtsi                     |  36 +++++
 arch/riscv/mach-litex/Kconfig                 |  11 ++
 arch/riscv/mach-litex/Makefile                |   3 +
 arch/riscv/mach-litex/include/mach/debug_ll.h | 124 ++++++++++++++++++
 common/bootm.c                                |   2 +
 drivers/serial/Makefile                       |   1 +
 drivers/serial/serial_litex.c                 |  99 ++++++++++++++
 12 files changed, 345 insertions(+), 2 deletions(-)
 create mode 100644 arch/riscv/configs/litex_defconfig
 create mode 100644 arch/riscv/dts/litex-generic.dts
 create mode 100644 arch/riscv/dts/litex.dtsi
 create mode 100644 arch/riscv/mach-litex/Kconfig
 create mode 100644 arch/riscv/mach-litex/Makefile
 create mode 100644 arch/riscv/mach-litex/include/mach/debug_ll.h
 create mode 100644 drivers/serial/serial_litex.c

-- 
2.20.1


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[RFC 1/4] riscv: add initial LiteX SoC support

[Antony Pavlov]

LiteX is a Migen-based System on Chip, supporting softcore VexRiscv CPU,
 a 32-bits Linux Capable RISC-V CPU.

See https://github.com/enjoy-digital/litex for details.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 arch/riscv/Kconfig                            |   6 +
 arch/riscv/Makefile                           |   1 +
 arch/riscv/dts/litex-generic.dts              |  17 +++
 arch/riscv/dts/litex.dtsi                     |  36 +++++
 arch/riscv/mach-litex/Kconfig                 |  11 ++
 arch/riscv/mach-litex/Makefile                |   3 +
 arch/riscv/mach-litex/include/mach/debug_ll.h | 124 ++++++++++++++++++
 7 files changed, 198 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 16c3eecce6..ca764d54d0 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -24,6 +24,11 @@ config MACH_ERIZO
 	select HAS_DEBUG_LL
 	select HAS_NMON
 
+config MACH_LITEX
+	bool "litex family"
+	select HAS_DEBUG_LL
+	select HAS_NMON
+
 endchoice
 
 choice
@@ -63,6 +68,7 @@ config BUILTIN_DTB_NAME
 	depends on BUILTIN_DTB
 
 source "arch/riscv/mach-erizo/Kconfig"
+source "arch/riscv/mach-litex/Kconfig"
 
 endmenu
 
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 643c0bc8eb..955a10cecb 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -12,6 +12,7 @@ LDFLAGS += $(ldflags-y)
 LDFLAGS_barebox += -nostdlib
 
 machine-$(CONFIG_MACH_ERIZO)	:= erizo
+machine-$(CONFIG_MACH_LITEX)	:= litex
 
 TEXT_BASE = $(CONFIG_TEXT_BASE)
 CPPFLAGS += -DTEXT_BASE=$(CONFIG_TEXT_BASE)
diff --git a/arch/riscv/dts/litex-generic.dts b/arch/riscv/dts/litex-generic.dts
new file mode 100644
index 0000000000..7dc0fa6c79
--- /dev/null
+++ b/arch/riscv/dts/litex-generic.dts
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "litex.dtsi"
+
+/ {
+	model = "LiteX VexRiscV";
+	compatible = "litex,vexriscv";
+
+	memory@40000000 {
+		device_type = "memory";
+		reg = <0x40000000 0x00800000>;
+	};
+};
+
+&uart0 {
+	status = "okay";
+};
diff --git a/arch/riscv/dts/litex.dtsi b/arch/riscv/dts/litex.dtsi
new file mode 100644
index 0000000000..dfd3d83404
--- /dev/null
+++ b/arch/riscv/dts/litex.dtsi
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/dts-v1/;
+
+/ {
+	compatible = "litex,vexriscv", "litex-dev";
+
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	clocks {
+		ref_clk: ref_clk {
+			#clock-cells = <0>;
+			compatible = "fixed-clock";
+			clock-frequency = <50000000>;
+		};
+	};
+
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			device_type = "cpu";
+			compatible = "spinalhdl,vexriscv", "riscv";
+			clocks = <&ref_clk>;
+			reg = <0>;
+		};
+	};
+
+	uart0: serial@e0001800 {
+		compatible = "litex,uart";
+		reg = <0xe0001800 0x18>;
+		status = "disabled";
+	};
+};
diff --git a/arch/riscv/mach-litex/Kconfig b/arch/riscv/mach-litex/Kconfig
new file mode 100644
index 0000000000..ab6cd2fa01
--- /dev/null
+++ b/arch/riscv/mach-litex/Kconfig
@@ -0,0 +1,11 @@
+if MACH_LITEX
+
+choice
+	prompt "Board type"
+
+config BOARD_LITEX_GENERIC
+	bool "litex generic board"
+
+endchoice
+
+endif
diff --git a/arch/riscv/mach-litex/Makefile b/arch/riscv/mach-litex/Makefile
new file mode 100644
index 0000000000..d9c51e74c3
--- /dev/null
+++ b/arch/riscv/mach-litex/Makefile
@@ -0,0 +1,3 @@
+# just to build a built-in.o. Otherwise compilation fails when no o-files is
+# created.
+obj- += dummy.o
diff --git a/arch/riscv/mach-litex/include/mach/debug_ll.h b/arch/riscv/mach-litex/include/mach/debug_ll.h
new file mode 100644
index 0000000000..aaf9f0b855
--- /dev/null
+++ b/arch/riscv/mach-litex/include/mach/debug_ll.h
@@ -0,0 +1,124 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2019 Antony Pavlov <antonynpavlov@gmail.com>
+ *
+ * This file is part of barebox.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __MACH_LITEX_DEBUG_LL__
+#define __MACH_LITEX_DEBUG_LL__
+
+/** @file
+ *  This File contains declaration for early output support
+ */
+
+#include <linux/kconfig.h>
+
+#define DEBUG_LL_UART_ADDR	0xe0001800
+#define UART_RXTX	0x00
+#define UART_TXFULL	0x04
+#define UART_RXEMPTY	0x08
+#define UART_EV_PENDING	0x10
+#define  UART_EV_RX	(1 << 1)
+#define UART_EV_ENABLE	0x14
+
+
+#ifndef __ASSEMBLY__
+
+/*
+ * C macros
+ */
+
+#include <asm/io.h>
+
+static inline void PUTC_LL(char ch)
+{
+#ifdef CONFIG_DEBUG_LL
+	/* wait for space */
+	while (__raw_readb((u8 *)DEBUG_LL_UART_ADDR + UART_TXFULL))
+		;
+
+	__raw_writeb(ch, (u8 *)DEBUG_LL_UART_ADDR + UART_RXTX);
+#endif /* CONFIG_DEBUG_LL */
+}
+#else /* __ASSEMBLY__ */
+/*
+ * Macros for use in assembly language code
+ */
+
+/*
+ * output a character in a0
+ */
+.macro	debug_ll_outc_a0
+#ifdef CONFIG_DEBUG_LL
+
+	li	t0, DEBUG_LL_UART_ADDR
+
+201:
+	lbu	t1, UART_TXFULL(t0)	/* uart tx full ? */
+	andi	t1, t1, 0xff
+	bnez	t1, 201b		/* try again */
+
+	sb	a0, UART_RXTX(t0)	/* write the character */
+
+#endif /* CONFIG_DEBUG_LL */
+.endm
+
+/*
+ * output a character
+ */
+.macro	debug_ll_outc chr
+#ifdef CONFIG_DEBUG_LL
+	li	a0, \chr
+	debug_ll_outc_a0
+#endif /* CONFIG_DEBUG_LL */
+.endm
+
+/*
+ * check character in input buffer
+ * return value:
+ *  v0 = 0   no character in input buffer
+ *  v0 != 0  character in input buffer
+ */
+.macro	debug_ll_tstc
+#ifdef CONFIG_DEBUG_LL
+	li	t0, DEBUG_LL_UART_ADDR
+
+	/* get line status and check for data present */
+	lbu	s0, UART_RXEMPTY(t0)
+	bnez    s0, 243f
+	li	s0, 1
+	j	244f
+243:	li	s0, 0
+244:	nop
+#endif /* CONFIG_DEBUG_LL */
+.endm
+
+/*
+ * get character to v0
+ */
+.macro	debug_ll_getc
+#ifdef CONFIG_DEBUG_LL
+
+204:
+	debug_ll_tstc
+
+	/* try again */
+	beqz	s0, 204b
+
+	/* read a character */
+	lb	s0, UART_RXTX(t0)
+	li      t1, UART_EV_RX
+	sb	t1, UART_EV_PENDING(t0)
+
+#endif /* CONFIG_DEBUG_LL */
+.endm
+#endif /* __ASSEMBLY__ */
+
+#endif /* __MACH_LITEX_DEBUG_LL__ */
-- 
2.20.1


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[RFC 2/4] serial: add litex UART driver

[Antony Pavlov]

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 drivers/serial/Makefile       |  1 +
 drivers/serial/serial_litex.c | 99 +++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)

diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 4174cc1ffb..fa86aa8c05 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_DRIVER_SERIAL_CADENCE)		+= serial_cadence.o
 obj-$(CONFIG_DRIVER_SERIAL_EFI_STDIO)		+= efi-stdio.o
 obj-$(CONFIG_DRIVER_SERIAL_DIGIC)		+= serial_digic.o
 obj-$(CONFIG_DRIVER_SERIAL_LPUART)		+= serial_lpuart.o
+obj-$(CONFIG_MACH_LITEX)			+= serial_litex.o
diff --git a/drivers/serial/serial_litex.c b/drivers/serial/serial_litex.c
new file mode 100644
index 0000000000..4a23921ac7
--- /dev/null
+++ b/drivers/serial/serial_litex.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.
+/*
+ * Copyright (C) 2019 Antony Pavlov <antonynpavlov@gmail.com>
+ *
+ * This file is part of barebox.
+ * See file CREDITS for list of people who contributed to this project.
+ *
+ */
+
+#include <common.h>
+#include <init.h>
+#include <malloc.h>
+#include <io.h>
+
+#include <mach/debug_ll.h>
+
+static inline uint32_t litex_serial_readb(struct console_device *cdev,
+						uint32_t offset)
+{
+	void __iomem *base = cdev->dev->priv;
+
+	return readb(base + offset);
+}
+
+static inline void litex_serial_writeb(struct console_device *cdev,
+					uint32_t value, uint32_t offset)
+{
+	void __iomem *base = cdev->dev->priv;
+
+	writeb(value, base + offset);
+}
+
+static void litex_serial_putc(struct console_device *cdev, char c)
+{
+	while (litex_serial_readb(cdev, UART_TXFULL))
+		;
+
+	litex_serial_writeb(cdev, c, UART_RXTX);
+}
+
+static int litex_serial_getc(struct console_device *cdev)
+{
+	int c;
+
+	while (litex_serial_readb(cdev, UART_RXEMPTY))
+		;
+
+	c = litex_serial_readb(cdev, UART_RXTX);
+
+	/* refresh UART_RXEMPTY by writing UART_EV_RX to UART_EV_PENDING */
+	litex_serial_writeb(cdev, UART_EV_RX, UART_EV_PENDING);
+
+	return c;
+}
+
+static int litex_serial_tstc(struct console_device *cdev)
+{
+	if (litex_serial_readb(cdev, UART_RXEMPTY)) {
+		return 0;
+	}
+
+	return 1;
+}
+
+static int litex_serial_probe(struct device_d *dev)
+{
+	struct resource *iores;
+	struct console_device *cdev;
+
+	cdev = xzalloc(sizeof(struct console_device));
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores))
+		return PTR_ERR(iores);
+	dev->priv = IOMEM(iores->start);
+	cdev->dev = dev;
+	cdev->tstc = &litex_serial_tstc;
+	cdev->putc = &litex_serial_putc;
+	cdev->getc = &litex_serial_getc;
+	cdev->setbrg = NULL;
+
+	console_register(cdev);
+
+	return 0;
+}
+
+static __maybe_unused struct of_device_id litex_serial_dt_ids[] = {
+	{
+		.compatible = "litex,uart",
+	}, {
+		/* sentinel */
+	}
+};
+
+static struct driver_d litex_serial_driver = {
+	.name  = "litex-uart",
+	.probe = litex_serial_probe,
+	.of_compatible = DRV_OF_COMPAT(litex_serial_dt_ids),
+};
+console_platform_driver(litex_serial_driver);
-- 
2.20.1


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[RFC 3/4] WIP: make it work on litex

[Antony Pavlov]

  * litex platform does not use ns16550 at all
    so debug_ll_ns16550_init should be eliminated;

  * there is no IH_ARCH_RISCV definition in include/image.h
    at the moment, so the error stops compiling:
        common/bootm.c: In function 'bootm_open_os_uimage':
        common/bootm.c:491:34: error: 'IH_ARCH' undeclared (first use in this
        function)
        if (data->os->header.ih_arch != IH_ARCH) {
                                        ^~~~~~~

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 arch/riscv/boot/start.S | 2 --
 common/bootm.c          | 2 ++
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/boot/start.S b/arch/riscv/boot/start.S
index d1dbe48b7b..fab23e926f 100644
--- a/arch/riscv/boot/start.S
+++ b/arch/riscv/boot/start.S
@@ -28,8 +28,6 @@
 
 .globl _start
 _start:
-	debug_ll_ns16550_init
-
 	riscv_nmon
 
 	li	sp, STACK_BASE + STACK_SIZE
diff --git a/common/bootm.c b/common/bootm.c
index 36f6c41bbd..37379ef03f 100644
--- a/common/bootm.c
+++ b/common/bootm.c
@@ -487,11 +487,13 @@ static int bootm_open_os_uimage(struct image_data *data)
 
 	uimage_print_contents(data->os);
 
+#if 0
 	if (data->os->header.ih_arch != IH_ARCH) {
 		printf("Unsupported Architecture 0x%x\n",
 		       data->os->header.ih_arch);
 		return -EINVAL;
 	}
+#endif
 
 	if (data->os_address == UIMAGE_SOME_ADDRESS)
 		data->os_address = data->os->header.ih_load;
-- 
2.20.1


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[RFC 4/4] riscv: add litex_defconfig

[Antony Pavlov]

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
---
 arch/riscv/configs/litex_defconfig | 45 ++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/arch/riscv/configs/litex_defconfig b/arch/riscv/configs/litex_defconfig
new file mode 100644
index 0000000000..cc8404e4b1
--- /dev/null
+++ b/arch/riscv/configs/litex_defconfig
@@ -0,0 +1,45 @@
+CONFIG_MACH_LITEX=y
+CONFIG_BUILTIN_DTB=y
+CONFIG_BUILTIN_DTB_NAME="litex-generic"
+CONFIG_NMON=y
+CONFIG_NMON_HELP=y
+CONFIG_TEXT_BASE=0x40000000
+CONFIG_MEMORY_LAYOUT_FIXED=y
+CONFIG_STACK_BASE=0x400e0000
+CONFIG_STACK_SIZE=0x20000
+CONFIG_MALLOC_BASE=0x40100000
+CONFIG_MALLOC_SIZE=0x100000
+CONFIG_MALLOC_TLSF=y
+CONFIG_PANIC_HANG=y
+CONFIG_HUSH_FANCY_PROMPT=y
+CONFIG_CMDLINE_EDITING=y
+CONFIG_AUTO_COMPLETE=y
+# CONFIG_ERRNO_MESSAGES is not set
+# CONFIG_TIMESTAMP is not set
+CONFIG_DEFAULT_ENVIRONMENT_GENERIC_NEW=y
+CONFIG_POLLER=y
+CONFIG_DEBUG_LL=y
+CONFIG_LONGHELP=y
+CONFIG_CMD_IOMEM=y
+CONFIG_CMD_IMD=y
+CONFIG_CMD_MEMINFO=y
+# CONFIG_CMD_BOOTM is not set
+CONFIG_CMD_GO=y
+CONFIG_CMD_LOADY=y
+CONFIG_CMD_CMP=y
+CONFIG_CMD_MD5SUM=y
+CONFIG_CMD_SHA1SUM=y
+CONFIG_CMD_MSLEEP=y
+CONFIG_CMD_SLEEP=y
+CONFIG_CMD_MEMTEST=y
+CONFIG_CMD_MM=y
+CONFIG_CMD_GPIO=y
+CONFIG_CMD_OF_DUMP=y
+CONFIG_CMD_TIME=y
+CONFIG_CMD_DHRYSTONE=y
+CONFIG_OFDEVICE=y
+# CONFIG_SPI is not set
+CONFIG_CLOCKSOURCE_DUMMY_RATE=60000
+CONFIG_GPIO_GENERIC_PLATFORM=y
+# CONFIG_PINCTRL is not set
+CONFIG_DIGEST_CRC32_GENERIC=y
-- 
2.20.1


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Re: [RFC 0/4] riscv: add initial LiteX SoC support

[Sam Ravnborg]

Hi Antony

Nice patch series, thanks for sharing.

On Sun, Jun 02, 2019 at 10:30:57AM +0300, Antony Pavlov wrote:
> This RFC patchseries adds initial LiteX RISC-V SoC support for barebox.
> 
> You can obtain this patchseries from github:
> 
>     $ git clone -b 20190602.litex https://github.com/frantony/barebox
> 
> LiteX is a Migen-based System on Chip [1], supporting softcore VexRiscv CPU,
>  a 32-bits Linux Capable RISC-V CPU [2].
> 
> All the components used to create the LiteX SoC are open-source and
> the flexibility of Spinal HDL/Migen allow targeting easily very various
> FPGA devices/boards: Lattice, Altera, Xilinx, Microsemi FPGAs
> with SDRAM/DDR/DDR2/DDR3/DDR4 RAMs, RMII/MII/RGMII/1000BASE-X Ethernet PHYs.
> 
> The LiteX SoC with VexRiscv CPU can be deployed on e.g. Digilent ARTY board [3]
> or Terasic DE0-Nano board [4].
> 
> You can boot barebox from serial port using flterm [5]:, e.g.:
> 
> flterm --port /dev/ttyUSB0 --kernel <path_to_barebox.bin> --kernel-adr 0x40000000

Can you be persuaded to include the above in a .rst file in
Documentation, so others can find this info later?

	Sam
> 
> 
> TODO
> ====
> 
>   * add pbl support for riscv barebox;
>   * add liteeth Ethernet core support [6] (tip: use ARTY board);
>   * fix issues (see the WIP commit);
>   * use barebox to start linux [2] and zephyr [7].
> 
> 
> REFERENCES
> ==========
> 
>  [1] https://github.com/enjoy-digital/litex
>  [2] https://github.com/enjoy-digital/linux-on-litex-vexriscv
>  [3] https://store.digilentinc.com/arty-a7-artix-7-fpga-development-board-for-makers-and-hobbyists/
>  [4] http://www.terasic.com.tw/cgi-bin/page/archive.pl?Language=English&No=593
>  [5] https://github.com/timvideos/flterm
>  [6] https://github.com/enjoy-digital/liteeth
>  [7] https://github.com/zephyrproject-rtos/zephyr/tree/master/boards/riscv32/litex_vexriscv
> 
> 
> Antony Pavlov (4):
>   riscv: add initial LiteX SoC support
>   serial: add litex UART driver
>   WIP: make it work on litex
>   riscv: add litex_defconfig
> 
>  arch/riscv/Kconfig                            |   6 +
>  arch/riscv/Makefile                           |   1 +
>  arch/riscv/boot/start.S                       |   2 -
>  arch/riscv/configs/litex_defconfig            |  45 +++++++
>  arch/riscv/dts/litex-generic.dts              |  17 +++
>  arch/riscv/dts/litex.dtsi                     |  36 +++++
>  arch/riscv/mach-litex/Kconfig                 |  11 ++
>  arch/riscv/mach-litex/Makefile                |   3 +
>  arch/riscv/mach-litex/include/mach/debug_ll.h | 124 ++++++++++++++++++
>  common/bootm.c                                |   2 +
>  drivers/serial/Makefile                       |   1 +
>  drivers/serial/serial_litex.c                 |  99 ++++++++++++++
>  12 files changed, 345 insertions(+), 2 deletions(-)
>  create mode 100644 arch/riscv/configs/litex_defconfig
>  create mode 100644 arch/riscv/dts/litex-generic.dts
>  create mode 100644 arch/riscv/dts/litex.dtsi
>  create mode 100644 arch/riscv/mach-litex/Kconfig
>  create mode 100644 arch/riscv/mach-litex/Makefile
>  create mode 100644 arch/riscv/mach-litex/include/mach/debug_ll.h
>  create mode 100644 drivers/serial/serial_litex.c
> 
> -- 
> 2.20.1
> 
> 
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> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox

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Re: [RFC 2/4] serial: add litex UART driver

[Ahmad Fatoum]

On 2/6/19 09:30, Antony Pavlov wrote:
> Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
> ---
>  drivers/serial/Makefile       |  1 +
>  drivers/serial/serial_litex.c | 99 +++++++++++++++++++++++++++++++++++
>  2 files changed, 100 insertions(+)
> 
> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> index 4174cc1ffb..fa86aa8c05 100644
> --- a/drivers/serial/Makefile
> +++ b/drivers/serial/Makefile
> @@ -23,3 +23,4 @@ obj-$(CONFIG_DRIVER_SERIAL_CADENCE)		+= serial_cadence.o
>  obj-$(CONFIG_DRIVER_SERIAL_EFI_STDIO)		+= efi-stdio.o
>  obj-$(CONFIG_DRIVER_SERIAL_DIGIC)		+= serial_digic.o
>  obj-$(CONFIG_DRIVER_SERIAL_LPUART)		+= serial_lpuart.o
> +obj-$(CONFIG_MACH_LITEX)			+= serial_litex.o
> diff --git a/drivers/serial/serial_litex.c b/drivers/serial/serial_litex.c
> new file mode 100644
> index 0000000000..4a23921ac7
> --- /dev/null
> +++ b/drivers/serial/serial_litex.c
> @@ -0,0 +1,99 @@
> +// SPDX-License-Identifier: GPL-2.

Rest of the line is missing is here.

> +/*
> + * Copyright (C) 2019 Antony Pavlov <antonynpavlov@gmail.com>
> + *
> + * This file is part of barebox.
> + * See file CREDITS for list of people who contributed to this project.
> + *
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <malloc.h>
> +#include <io.h>
> +
> +#include <mach/debug_ll.h>

left-over header?

> +
> +static inline uint32_t litex_serial_readb(struct console_device *cdev,
> +						uint32_t offset)

Not a problem here, but I find it strange to have a readb that returns uint32_t.

> +{
> +	void __iomem *base = cdev->dev->priv;
> +
> +	return readb(base + offset);
> +}
> +
> +static inline void litex_serial_writeb(struct console_device *cdev,
> +					uint32_t value, uint32_t offset)
> +{
> +	void __iomem *base = cdev->dev->priv;
> +
> +	writeb(value, base + offset);
> +}
> +
> +static void litex_serial_putc(struct console_device *cdev, char c)
> +{
> +	while (litex_serial_readb(cdev, UART_TXFULL))
> +		;
> +
> +	litex_serial_writeb(cdev, c, UART_RXTX);
> +}
> +
> +static int litex_serial_getc(struct console_device *cdev)
> +{
> +	int c;
> +
> +	while (litex_serial_readb(cdev, UART_RXEMPTY))
> +		;
> +
> +	c = litex_serial_readb(cdev, UART_RXTX);
> +
> +	/* refresh UART_RXEMPTY by writing UART_EV_RX to UART_EV_PENDING */
> +	litex_serial_writeb(cdev, UART_EV_RX, UART_EV_PENDING);
> +
> +	return c;
> +}
> +
> +static int litex_serial_tstc(struct console_device *cdev)
> +{
> +	if (litex_serial_readb(cdev, UART_RXEMPTY)) {
> +		return 0;
> +	}
> +
> +	return 1;

return !litex_serial_readb(cdev, UART_RXEMPTY)); ?

> +}
> +
> +static int litex_serial_probe(struct device_d *dev)
> +{
> +	struct resource *iores;
> +	struct console_device *cdev;
> +
> +	cdev = xzalloc(sizeof(struct console_device));
> +	iores = dev_request_mem_resource(dev, 0);
> +	if (IS_ERR(iores))
> +		return PTR_ERR(iores);
> +	dev->priv = IOMEM(iores->start);
> +	cdev->dev = dev;
> +	cdev->tstc = &litex_serial_tstc;
> +	cdev->putc = &litex_serial_putc;
> +	cdev->getc = &litex_serial_getc;
> +	cdev->setbrg = NULL;
> +
> +	console_register(cdev);
> +
> +	return 0;
> +}
> +
> +static __maybe_unused struct of_device_id litex_serial_dt_ids[] = {
> +	{
> +		.compatible = "litex,uart",
> +	}, {
> +		/* sentinel */
> +	}
> +};
> +
> +static struct driver_d litex_serial_driver = {
> +	.name  = "litex-uart",
> +	.probe = litex_serial_probe,
> +	.of_compatible = DRV_OF_COMPAT(litex_serial_dt_ids),
> +};
> +console_platform_driver(litex_serial_driver);
> 

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: [RFC 2/4] serial: add litex UART driver

[Ahmad Fatoum]

On 3/6/19 07:10, Ahmad Fatoum wrote:
> On 2/6/19 09:30, Antony Pavlov wrote:
>> Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
>> ---
>>  drivers/serial/Makefile       |  1 +
>>  drivers/serial/serial_litex.c | 99 +++++++++++++++++++++++++++++++++++
>>  2 files changed, 100 insertions(+)
>>
>> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
>> index 4174cc1ffb..fa86aa8c05 100644
>> --- a/drivers/serial/Makefile
>> +++ b/drivers/serial/Makefile

>> +
>> +#include <mach/debug_ll.h>
> 
> left-over header?

Ah never mind, it's used for the register definitions.

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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Re: [RFC 3/4] WIP: make it work on litex

[Sascha Hauer]

On Sun, Jun 02, 2019 at 10:31:00AM +0300, Antony Pavlov wrote:
>   * litex platform does not use ns16550 at all
>     so debug_ll_ns16550_init should be eliminated;
> 
>   * there is no IH_ARCH_RISCV definition in include/image.h
>     at the moment, so the error stops compiling:
>         common/bootm.c: In function 'bootm_open_os_uimage':
>         common/bootm.c:491:34: error: 'IH_ARCH' undeclared (first use in this
>         function)
>         if (data->os->header.ih_arch != IH_ARCH) {
>                                         ^~~~~~~

U-Boot has IH_ARCH_RISCV already, you can copy it there.

> 
> Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
> ---
>  arch/riscv/boot/start.S | 2 --
>  common/bootm.c          | 2 ++
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/boot/start.S b/arch/riscv/boot/start.S
> index d1dbe48b7b..fab23e926f 100644
> --- a/arch/riscv/boot/start.S
> +++ b/arch/riscv/boot/start.S
> @@ -28,8 +28,6 @@
>  
>  .globl _start
>  _start:
> -	debug_ll_ns16550_init
> -

This should be done by board code.

Sascha

-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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