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afa6b1ccfa
The RISC-V ISA defines a simple console that is availiable via SBI calls on all systems. The SBI console is designed to be availiable at all times, so while it's most natural to use this as an early printk target it's also possible to use this as the system console when there isn't a better one availiable. This patch adds support for the RISC-V SBI console via the HVC infastructure. It's entirely independent from our early printk support, which results in early boot messages appearing twice over the SBI console. As far as I can tell that's the fault of our early printk support (we should support earlycon) as opposed to this driver. There is one checkpatch.pl warning here: to check the MAINTAINERS file. They're all matched by the "K: riscv" line. Signed-off-by: Palmer Dabbelt <palmer@sifive.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
61 lines
1.1 KiB
C
61 lines
1.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2008 David Gibson, IBM Corporation
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* Copyright (C) 2012 Regents of the University of California
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* Copyright (C) 2017 SiFive
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*/
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#include <linux/console.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <asm/sbi.h>
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#include "hvc_console.h"
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static int hvc_sbi_tty_put(uint32_t vtermno, const char *buf, int count)
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{
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int i;
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for (i = 0; i < count; i++)
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sbi_console_putchar(buf[i]);
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return i;
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}
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static int hvc_sbi_tty_get(uint32_t vtermno, char *buf, int count)
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{
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int i, c;
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for (i = 0; i < count; i++) {
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c = sbi_console_getchar();
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if (c < 0)
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break;
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buf[i] = c;
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}
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return i;
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}
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static const struct hv_ops hvc_sbi_ops = {
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.get_chars = hvc_sbi_tty_get,
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.put_chars = hvc_sbi_tty_put,
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};
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static int __init hvc_sbi_init(void)
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{
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return PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_ops, 16));
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}
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device_initcall(hvc_sbi_init);
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static int __init hvc_sbi_console_init(void)
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{
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hvc_instantiate(0, 0, &hvc_sbi_ops);
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add_preferred_console("hvc", 0, NULL);
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return 0;
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}
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console_initcall(hvc_sbi_console_init);
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