Re: [PATCH] x86: EuroBraille/Iris power off

[Shérab <Sebastien.Hinderer@ens-lyon.org>]

Dear all,

Valdis.Kletnieks@vt.edu (2010/09/13 21:45 -0400):
> On Mon, 13 Sep 2010 17:22:49 +0200, Samuel Thibault said:
> 
> > Again, I'm not sure we really should try hard to make it automatically
> > detected (and thus always enabled).  Having to pass a kernel parameter
> > to enable the functionality is completely fine, since installing Linux
> > on this device requires quite some tinkering already.
> 
> I'm agreeing that if iris_init() checks that the user passed 'irisinit.force=1'
> on the command line or as a module parameter, and bailed immediately if it
> wasn't passed, then doing the inb() and testing it should be safe
> enough. [...]

Please find below a revised version of the module that does what has
been asked.

Cheers,
Shérab.

>From c7d27a83ba8ec5e5c18f1ef02af4f740f4db1b7b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sh=C3=A9rab?= <Sebastien.Hinderer@ens-lyon.org>
Date: Mon, 20 Sep 2010 10:15:16 +0200
Subject: [PATCH] Eurobraille/Iris power off.
 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.
Content-Type: text/plain; charset="utf-8"

---
 arch/x86/Kconfig         |   13 +++++++
 arch/x86/kernel/Makefile |    1 +
 arch/x86/kernel/iris.c   |   90 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 104 insertions(+), 0 deletions(-)
 create mode 100644 arch/x86/kernel/iris.c

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index cea0cd9..7c8e261 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -493,6 +493,19 @@ 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"
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 0925676..98dd1c8 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -115,6 +115,7 @@ 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
diff --git a/arch/x86/kernel/iris.c b/arch/x86/kernel/iris.c
new file mode 100644
index 0000000..83a913b
--- /dev/null
+++ b/arch/x86/kernel/iris.c
@@ -0,0 +1,90 @@
+/*
+ * 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/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/pm.h>
+#include <linux/delay.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 0x0 /* 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);
+
-- 
1.7.1