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51 lines
1.1 KiB
51 lines
1.1 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 2012 ARM Ltd. |
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* Author: Marc Zyngier <[email protected]> |
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* |
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* Adapted for ARM and earlycon: |
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* Copyright (C) 2014 Linaro Ltd. |
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* Author: Rob Herring <[email protected]> |
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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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#ifdef CONFIG_THUMB2_KERNEL |
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#define SEMIHOST_SWI "0xab" |
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#else |
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#define SEMIHOST_SWI "0x123456" |
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#endif |
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/* |
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* Semihosting-based debug console |
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*/ |
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static void smh_putc(struct uart_port *port, int c) |
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{ |
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#ifdef CONFIG_ARM64 |
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asm volatile("mov x1, %0\n" |
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"mov x0, #3\n" |
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"hlt 0xf000\n" |
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: : "r" (&c) : "x0", "x1", "memory"); |
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#else |
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asm volatile("mov r1, %0\n" |
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"mov r0, #3\n" |
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"svc " SEMIHOST_SWI "\n" |
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: : "r" (&c) : "r0", "r1", "memory"); |
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#endif |
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} |
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static void smh_write(struct console *con, const char *s, unsigned n) |
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{ |
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struct earlycon_device *dev = con->data; |
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uart_console_write(&dev->port, s, n, smh_putc); |
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} |
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static int |
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__init early_smh_setup(struct earlycon_device *device, const char *opt) |
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{ |
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device->con->write = smh_write; |
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return 0; |
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} |
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EARLYCON_DECLARE(smh, early_smh_setup);
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