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a9f96f014f
Now that the SPDX tag is in all tty files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Jiri Slaby <jslaby@suse.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Metcalf <cmetcalf@mellanox.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
88 lines
1.6 KiB
C
88 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2010, 2014 The Linux Foundation. All rights reserved. */
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#include <linux/init.h>
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#include <asm/dcc.h>
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#include <asm/processor.h>
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#include "hvc_console.h"
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/* DCC Status Bits */
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#define DCC_STATUS_RX (1 << 30)
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#define DCC_STATUS_TX (1 << 29)
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static int hvc_dcc_put_chars(uint32_t vt, 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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while (__dcc_getstatus() & DCC_STATUS_TX)
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cpu_relax();
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__dcc_putchar(buf[i]);
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}
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return count;
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}
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static int hvc_dcc_get_chars(uint32_t vt, 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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if (__dcc_getstatus() & DCC_STATUS_RX)
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buf[i] = __dcc_getchar();
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else
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break;
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return i;
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}
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static bool hvc_dcc_check(void)
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{
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unsigned long time = jiffies + (HZ / 10);
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/* Write a test character to check if it is handled */
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__dcc_putchar('\n');
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while (time_is_after_jiffies(time)) {
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if (!(__dcc_getstatus() & DCC_STATUS_TX))
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return true;
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}
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return false;
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}
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static const struct hv_ops hvc_dcc_get_put_ops = {
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.get_chars = hvc_dcc_get_chars,
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.put_chars = hvc_dcc_put_chars,
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};
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static int __init hvc_dcc_console_init(void)
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{
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int ret;
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if (!hvc_dcc_check())
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return -ENODEV;
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/* Returns -1 if error */
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ret = hvc_instantiate(0, 0, &hvc_dcc_get_put_ops);
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return ret < 0 ? -ENODEV : 0;
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}
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console_initcall(hvc_dcc_console_init);
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static int __init hvc_dcc_init(void)
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{
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struct hvc_struct *p;
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if (!hvc_dcc_check())
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return -ENODEV;
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p = hvc_alloc(0, 0, &hvc_dcc_get_put_ops, 128);
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return PTR_ERR_OR_ZERO(p);
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}
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device_initcall(hvc_dcc_init);
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