The RISC-V ISA defines a simple console that is availiable via SBI calls on all systems. This patch adds a driver for this console interface that can act as both a target for early printk and as the system console. Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxx> --- arch/riscv/include/asm/hvc_riscv_sbi.h | 25 ++++++++++ drivers/tty/hvc/Kconfig | 11 +++++ drivers/tty/hvc/Makefile | 1 + drivers/tty/hvc/hvc_riscv_sbi.c | 90 ++++++++++++++++++++++++++++++++++ 4 files changed, 127 insertions(+) create mode 100644 arch/riscv/include/asm/hvc_riscv_sbi.h create mode 100644 drivers/tty/hvc/hvc_riscv_sbi.c diff --git a/arch/riscv/include/asm/hvc_riscv_sbi.h b/arch/riscv/include/asm/hvc_riscv_sbi.h new file mode 100644 index 000000000000..d4f3cf0c17e9 --- /dev/null +++ b/arch/riscv/include/asm/hvc_riscv_sbi.h @@ -0,0 +1,25 @@ +/* + * RISC-V SBI console interface + * + * Copyright (C) 2017 SiFive + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * 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 _ASM_RISCV_HVC_RISCV_SBI_H +#define _ASM_RISCV_HVC_RISCV_SBI_H + +/* + * We always support CONFIG_EARLY_PRINTK via the SBI console driver because it + * works well enough that there's no penalty to doing so. + */ +extern struct console riscv_sbi_early_console_dev __initdata; + +#endif diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig index b8d5ea0ae26b..abe331761bdb 100644 --- a/drivers/tty/hvc/Kconfig +++ b/drivers/tty/hvc/Kconfig @@ -97,6 +97,17 @@ config HVC_BFIN_JTAG the HVC driver. If you don't have JTAG, then you probably don't want this option. +config HVC_RISCV_SBI + bool "RISC-V SBI console support" + depends on RISCV + select HVC_DRIVER + default y + help + This enables support for console output via RISC-V SBI calls, which + is normally used only during boot to output printk. + + If you don't know what do to here, say Y. + config HVCS tristate "IBM Hypervisor Virtual Console Server support" depends on PPC_PSERIES && HVC_CONSOLE diff --git a/drivers/tty/hvc/Makefile b/drivers/tty/hvc/Makefile index 6a2702be76d1..be497f9312d1 100644 --- a/drivers/tty/hvc/Makefile +++ b/drivers/tty/hvc/Makefile @@ -11,3 +11,4 @@ obj-$(CONFIG_HVC_IUCV) += hvc_iucv.o obj-$(CONFIG_HVC_UDBG) += hvc_udbg.o obj-$(CONFIG_HVC_BFIN_JTAG) += hvc_bfin_jtag.o obj-$(CONFIG_HVCS) += hvcs.o +obj-$(CONFIG_HVC_RISCV_SBI) += hvc_riscv_sbi.o diff --git a/drivers/tty/hvc/hvc_riscv_sbi.c b/drivers/tty/hvc/hvc_riscv_sbi.c new file mode 100644 index 000000000000..2548d658e110 --- /dev/null +++ b/drivers/tty/hvc/hvc_riscv_sbi.c @@ -0,0 +1,90 @@ +/* + * RISC-V SBI interface to hvc_console.c + * based on drivers-tty/hvc/hvc_udbg.c + * + * Copyright (C) 2008 David Gibson, IBM Corporation + * Copyright (C) 2012 Regents of the University of California + * Copyright (C) 2017 SiFive + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * 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. + */ + +#include <linux/console.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/moduleparam.h> +#include <linux/types.h> + +#include <asm/sbi.h> +#include <asm/hvc_riscv_sbi.h> + +#include "hvc_console.h" + +static int hvc_sbi_tty_put(uint32_t vtermno, const char *buf, int count) +{ + int i; + + for (i = 0; i < count; i++) + sbi_console_putchar(buf[i]); + + return i; +} + +static int hvc_sbi_tty_get(uint32_t vtermno, char *buf, int count) +{ + int i, c; + + for (i = 0; i < count; i++) { + if ((c = sbi_console_getchar()) < 0) + break; + buf[i] = c; + } + + return i; +} + +static const struct hv_ops hvc_sbi_ops = { + .get_chars = hvc_sbi_tty_get, + .put_chars = hvc_sbi_tty_put, +}; + +static int __init hvc_sbi_init(void) +{ + return PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_ops, 16)); +} +device_initcall(hvc_sbi_init); + +static int __init hvc_sbi_console_init(void) +{ + hvc_instantiate(0, 0, &hvc_sbi_ops); + add_preferred_console("hvc", 0, NULL); + + return 0; +} +console_initcall(hvc_sbi_console_init); + +static void sbi_console_write(struct console *co, const char *buf, + unsigned int n) +{ + int i; + + for (i = 0; i < n; ++i) { + if (buf[i] == '\n') + sbi_console_putchar('\r'); + sbi_console_putchar(buf[i]); + } +} + +struct console riscv_sbi_early_console_dev __initdata = { + .name = "early", + .write = sbi_console_write, + .flags = CON_PRINTBUFFER | CON_BOOT | CON_ANYTIME, + .index = -1 +}; -- 2.13.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html