mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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92 lines
2.8 KiB
C
92 lines
2.8 KiB
C
/*
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* Eurobraille/Iris power off support.
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*
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* Eurobraille's Iris machine is a PC with no APM or ACPI support.
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* It is shutdown by a special I/O sequence which this module provides.
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*
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* Copyright (C) Shérab <Sebastien.Hinderer@ens-lyon.org>
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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 the program ; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/moduleparam.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/pm.h>
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#include <asm/io.h>
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#define IRIS_GIO_BASE 0x340
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#define IRIS_GIO_INPUT IRIS_GIO_BASE
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#define IRIS_GIO_OUTPUT (IRIS_GIO_BASE + 1)
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#define IRIS_GIO_PULSE 0x80 /* First byte to send */
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#define IRIS_GIO_REST 0x00 /* Second byte to send */
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#define IRIS_GIO_NODEV 0xff /* Likely not an Iris */
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org>");
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MODULE_DESCRIPTION("A power_off handler for Iris devices from EuroBraille");
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MODULE_SUPPORTED_DEVICE("Eurobraille/Iris");
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static int force;
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module_param(force, bool, 0);
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MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation.");
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static void (*old_pm_power_off)(void);
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static void iris_power_off(void)
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{
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outb(IRIS_GIO_PULSE, IRIS_GIO_OUTPUT);
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msleep(850);
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outb(IRIS_GIO_REST, IRIS_GIO_OUTPUT);
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}
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/*
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* Before installing the power_off handler, try to make sure the OS is
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* running on an Iris. Since Iris does not support DMI, this is done
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* by reading its input port and seeing whether the read value is
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* meaningful.
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*/
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static int iris_init(void)
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{
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unsigned char status;
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if (force != 1) {
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printk(KERN_ERR "The force parameter has not been set to 1 so the Iris poweroff handler will not be installed.\n");
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return -ENODEV;
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}
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status = inb(IRIS_GIO_INPUT);
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if (status == IRIS_GIO_NODEV) {
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printk(KERN_ERR "This machine does not seem to be an Iris. Power_off handler not installed.\n");
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return -ENODEV;
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}
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old_pm_power_off = pm_power_off;
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pm_power_off = &iris_power_off;
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printk(KERN_INFO "Iris power_off handler installed.\n");
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return 0;
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}
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static void iris_exit(void)
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{
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pm_power_off = old_pm_power_off;
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printk(KERN_INFO "Iris power_off handler uninstalled.\n");
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}
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module_init(iris_init);
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module_exit(iris_exit);
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