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27de1f541f
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> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Palmer Dabbelt <palmer@sifive.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
29 lines
604 B
C
29 lines
604 B
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* RISC-V SBI based earlycon
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*
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* Copyright (C) 2018 Anup Patel <anup@brainfault.org>
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*/
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#include <linux/kernel.h>
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#include <linux/console.h>
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#include <linux/init.h>
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#include <linux/serial_core.h>
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#include <asm/sbi.h>
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static void sbi_console_write(struct console *con,
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const char *s, unsigned int n)
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{
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int i;
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for (i = 0; i < n; ++i)
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sbi_console_putchar(s[i]);
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}
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static int __init early_sbi_setup(struct earlycon_device *device,
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const char *opt)
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{
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device->con->write = sbi_console_write;
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return 0;
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}
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EARLYCON_DECLARE(sbi, early_sbi_setup);
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