x86/platform: Add Eurobraille/Iris power off support

The Iris machines from Eurobraille do not have APM or ACPI support
to shut themselves down properly.  A special I/O sequence is
needed to do so.  This modle runs this I/O sequence at
kernel shutdown when its force parameter is set to 1.

Signed-off-by: Shérab <Sebastien.Hinderer@ens-lyon.org>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
[ did minor coding style edits ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/Kconfig

@@ -482,6 +482,19 @@ config X86_ES7000
 	  Support for Unisys ES7000 systems.  Say 'Y' here if this kernel is
 	  supposed to run on an IA32-based Unisys ES7000 system.
 
+config X86_32_IRIS
+	tristate "Eurobraille/Iris poweroff module"
+	depends on X86_32
+	---help---
+	  The Iris machines from EuroBraille do not have APM or ACPI support
+	  to shut themselves down properly.  A special I/O sequence is
+	  needed to do so, which is what this module does at
+	  kernel shutdown.
+
+	  This is only for Iris machines from EuroBraille.
+
+	  If unused, say N.
+
 config SCHED_OMIT_FRAME_POINTER
 	def_bool y
 	prompt "Single-depth WCHAN output"

arch/x86/kernel/Makefile

@@ -109,6 +109,7 @@ obj-$(CONFIG_MICROCODE)			+= microcode.o
 obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o
 
 obj-$(CONFIG_SWIOTLB)			+= pci-swiotlb.o
+obj-$(CONFIG_X86_32_IRIS)		+= iris.o
 
 ###
 # 64 bit specific files

arch/x86/kernel/iris.c

@@ -0,0 +1,91 @@
+/*
+ * Eurobraille/Iris power off support.
+ *
+ * Eurobraille's Iris machine is a PC with no APM or ACPI support.
+ * It is shutdown by a special I/O sequence which this module provides.
+ *
+ *  Copyright (C) Shérab <Sebastien.Hinderer@ens-lyon.org>
+ *
+ * This program is free software ; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation ; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY ; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with the program ; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/moduleparam.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/pm.h>
+#include <asm/io.h>
+
+#define IRIS_GIO_BASE		0x340
+#define IRIS_GIO_INPUT		IRIS_GIO_BASE
+#define IRIS_GIO_OUTPUT		(IRIS_GIO_BASE + 1)
+#define IRIS_GIO_PULSE		0x80 /* First byte to send */
+#define IRIS_GIO_REST		0x00 /* Second byte to send */
+#define IRIS_GIO_NODEV		0xff /* Likely not an Iris */
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sébastien Hinderer <Sebastien.Hinderer@ens-lyon.org>");
+MODULE_DESCRIPTION("A power_off handler for Iris devices from EuroBraille");
+MODULE_SUPPORTED_DEVICE("Eurobraille/Iris");
+
+static int force;
+
+module_param(force, bool, 0);
+MODULE_PARM_DESC(force, "Set to one to force poweroff handler installation.");
+
+static void (*old_pm_power_off)(void);
+
+static void iris_power_off(void)
+{
+	outb(IRIS_GIO_PULSE, IRIS_GIO_OUTPUT);
+	msleep(850);
+	outb(IRIS_GIO_REST, IRIS_GIO_OUTPUT);
+}
+
+/*
+ * Before installing the power_off handler, try to make sure the OS is
+ * running on an Iris.  Since Iris does not support DMI, this is done
+ * by reading its input port and seeing whether the read value is
+ * meaningful.
+ */
+static int iris_init(void)
+{
+	unsigned char status;
+	if (force != 1) {
+		printk(KERN_ERR "The force parameter has not been set to 1 so the Iris poweroff handler will not be installed.\n");
+		return -ENODEV;
+	}
+	status = inb(IRIS_GIO_INPUT);
+	if (status == IRIS_GIO_NODEV) {
+		printk(KERN_ERR "This machine does not seem to be an Iris. Power_off handler not installed.\n");
+		return -ENODEV;
+	}
+	old_pm_power_off = pm_power_off;
+	pm_power_off = &iris_power_off;
+	printk(KERN_INFO "Iris power_off handler installed.\n");
+
+	return 0;
+}
+
+static void iris_exit(void)
+{
+	pm_power_off = old_pm_power_off;
+	printk(KERN_INFO "Iris power_off handler uninstalled.\n");
+}
+
+module_init(iris_init);
+module_exit(iris_exit);