From: Palmer Dabbelt <palmer@sifive.com>
To: anup@brainfault.org
Cc: robh@kernel.org, aou@eecs.berkeley.edu,
Greg KH <gregkh@linuxfoundation.org>,
anup@brainfault.org, linux-kernel@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
atish.patra@wdc.com, linux-serial@vger.kernel.org,
jslaby@suse.com, linux-riscv@lists.infradead.org
Subject: Re: [PATCH 1/3] tty/serial: Add RISC-V SBI earlycon support
Date: Fri, 07 Dec 2018 10:30:27 -0800 (PST) [thread overview]
Message-ID: <mhng-03b5ef96-37b8-4a95-94fa-2fb5e8e59da3@palmer-si-x1c4> (raw)
In-Reply-To: <20181204135507.3706-2-anup@brainfault.org>
On Tue, 04 Dec 2018 05:55:05 PST (-0800), anup@brainfault.org wrote:
> In RISC-V, the M-mode runtime firmware provide SBI calls for
> debug prints. This patch adds earlycon support using RISC-V
> SBI console calls. To enable it, just pass "earlycon=sbi" in
> kernel parameters.
>
> Signed-off-by: Anup Patel <anup@brainfault.org>
> ---
> drivers/tty/serial/Kconfig | 12 +++++++++++
> drivers/tty/serial/Makefile | 1 +
> drivers/tty/serial/earlycon-riscv-sbi.c | 28 +++++++++++++++++++++++++
> 3 files changed, 41 insertions(+)
> create mode 100644 drivers/tty/serial/earlycon-riscv-sbi.c
>
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 32886c304641..287bb41ac814 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -85,6 +85,18 @@ config SERIAL_EARLYCON_ARM_SEMIHOST
> with "earlycon=smh" on the kernel command line. The console is
> enabled when early_param is processed.
>
> +config SERIAL_EARLYCON_RISCV_SBI
> + bool "Early console using RISC-V SBI"
> + depends on RISCV
> + select SERIAL_CORE
> + select SERIAL_CORE_CONSOLE
> + select SERIAL_EARLYCON
> + help
> + Support for early debug console using RISC-V SBI. This enables
> + the console before standard serial driver is probed. This is enabled
> + with "earlycon=sbi" on the kernel command line. The console is
> + enabled when early_param is processed.
> +
> config SERIAL_SB1250_DUART
> tristate "BCM1xxx on-chip DUART serial support"
> depends on SIBYTE_SB1xxx_SOC=y
> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
> index daac675612df..3ce26ce08616 100644
> --- a/drivers/tty/serial/Makefile
> +++ b/drivers/tty/serial/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_SERIAL_CORE) += serial_core.o
>
> obj-$(CONFIG_SERIAL_EARLYCON) += earlycon.o
> obj-$(CONFIG_SERIAL_EARLYCON_ARM_SEMIHOST) += earlycon-arm-semihost.o
> +obj-$(CONFIG_SERIAL_EARLYCON_RISCV_SBI) += earlycon-riscv-sbi.o
>
> # These Sparc drivers have to appear before others such as 8250
> # which share ttySx minor node space. Otherwise console device
> diff --git a/drivers/tty/serial/earlycon-riscv-sbi.c b/drivers/tty/serial/earlycon-riscv-sbi.c
> new file mode 100644
> index 000000000000..e1a551aae336
> --- /dev/null
> +++ b/drivers/tty/serial/earlycon-riscv-sbi.c
> @@ -0,0 +1,28 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * RISC-V SBI based earlycon
> + *
> + * Copyright (C) 2018 Anup Patel <anup@brainfault.org>
> + */
> +#include <linux/kernel.h>
> +#include <linux/console.h>
> +#include <linux/init.h>
> +#include <linux/serial_core.h>
> +#include <asm/sbi.h>
> +
> +static void sbi_console_write(struct console *con,
> + const char *s, unsigned int n)
> +{
> + int i;
> +
> + for (i = 0; i < n; ++i)
> + sbi_console_putchar(s[i]);
> +}
> +
> +static int __init early_sbi_setup(struct earlycon_device *device,
> + const char *opt)
> +{
> + device->con->write = sbi_console_write;
> + return 0;
> +}
> +EARLYCON_DECLARE(sbi, early_sbi_setup);
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2018-12-07 18:30 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-04 13:55 [PATCH 0/3] RISC-V SBI earlycon Anup Patel
2018-12-04 13:55 ` [PATCH 1/3] tty/serial: Add RISC-V SBI earlycon support Anup Patel
2018-12-05 9:58 ` Greg Kroah-Hartman
2018-12-07 18:45 ` Palmer Dabbelt
2018-12-07 18:30 ` Palmer Dabbelt [this message]
2019-01-10 14:07 ` [PATCH] tty/serial: emit CR before NL in RISC-V SBL console Andreas Schwab
2019-01-10 15:16 ` Anup Patel
2019-01-10 15:26 ` Andreas Schwab
2019-01-10 16:17 ` Anup Patel
2019-01-10 17:11 ` [PATCH] tty/serial: use uart_console_write in the RISC-V SBL early console Andreas Schwab
2019-01-11 11:13 ` Anup Patel
2019-01-23 23:58 ` Palmer Dabbelt
2019-01-15 13:59 ` Christoph Hellwig
2019-01-10 20:54 ` [PATCH] tty/serial: emit CR before NL in RISC-V SBL console Palmer Dabbelt
2018-12-04 13:55 ` [PATCH 2/3] RISC-V: defconfig: Enable RISC-V SBI earlycon support Anup Patel
2018-12-07 18:30 ` Palmer Dabbelt
2018-12-04 13:55 ` [PATCH 3/3] RISC-V: Remove EARLY_PRINTK support Anup Patel
2018-12-07 18:30 ` Palmer Dabbelt
2018-12-07 18:30 ` [PATCH 0/3] RISC-V SBI earlycon Palmer Dabbelt
2019-03-25 16:23 ` Andreas Schwab
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=mhng-03b5ef96-37b8-4a95-94fa-2fb5e8e59da3@palmer-si-x1c4 \
--to=palmer@sifive.com \
--cc=anup@brainfault.org \
--cc=aou@eecs.berkeley.edu \
--cc=atish.patra@wdc.com \
--cc=gregkh@linuxfoundation.org \
--cc=hch@infradead.org \
--cc=jslaby@suse.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=linux-serial@vger.kernel.org \
--cc=robh@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).