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https://github.com/edk2-porting/linux-next.git
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d5e5491343
This adds a new backend for the hvc console based on the low-level udbg callbacks. This effectively implements a working runtime console in terms of the simple udbg primitives. This is kind of a hack - since udbg isn't something you really want to be using routinely - but it's really useful during bringup. This can be used to quickly implement a userspace-usable console while you're working on a proper driver for whatever console I/O device the hardware has. Or, it can be used to avoid writing a full blown tty/console driver entirely for quick-and-dirty I/O hardware that will later be replaced by something else. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
97 lines
2.0 KiB
C
97 lines
2.0 KiB
C
/*
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* udbg interface to hvc_console.c
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*
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* (C) Copyright David Gibson, IBM Corporation 2008.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/console.h>
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#include <linux/delay.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 <linux/irq.h>
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#include <asm/udbg.h>
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#include "hvc_console.h"
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struct hvc_struct *hvc_udbg_dev;
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static int hvc_udbg_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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udbg_putc(buf[i]);
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return i;
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}
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static int hvc_udbg_get(uint32_t vtermno, char *buf, int count)
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{
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int i, c;
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if (!udbg_getc_poll)
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return 0;
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for (i = 0; i < count; i++) {
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if ((c = udbg_getc_poll()) == -1)
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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 struct hv_ops hvc_udbg_ops = {
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.get_chars = hvc_udbg_get,
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.put_chars = hvc_udbg_put,
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};
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static int __init hvc_udbg_init(void)
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{
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struct hvc_struct *hp;
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BUG_ON(hvc_udbg_dev);
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hp = hvc_alloc(0, NO_IRQ, &hvc_udbg_ops, 16);
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if (IS_ERR(hp))
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return PTR_ERR(hp);
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hvc_udbg_dev = hp;
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return 0;
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}
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module_init(hvc_udbg_init);
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static void __exit hvc_udbg_exit(void)
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{
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if (hvc_udbg_dev)
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hvc_remove(hvc_udbg_dev);
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}
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module_exit(hvc_udbg_exit);
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static int __init hvc_udbg_console_init(void)
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{
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hvc_instantiate(0, 0, &hvc_udbg_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_udbg_console_init);
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