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Subject[RFC][Patch] IBM Real-Time "SMI Free" mode drive -v2
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This driver supports the Real-Time Linux (RTL) BIOS feature.  The RTL
feature allows non-fatal System Management Interrupts (SMIs) to be
disabled on supported IBM platforms.


The Device is presented as a special "_rtl_" table to the OS in the
Extended BIOS Data Area. There is a simple protocol for entering and
exiting the mode at runtime. This driver creates a simple sysfs
interface to allow a simple entry and exit from RTL mode in the
UFI/BIOS.


Signed-off-by: Keith Mannthey <kmannth@us.ibm.com>

---

--- linux-2.6.32/drivers/misc/ibmrtl/ibm_rtl.c 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.32-rtl/drivers/misc/ibmrtl/ibm_rtl.c 2009-12-14 16:37:19.000000000 -0800
@@ -0,0 +1,189 @@
+/*
+ * IBM Premium Real-Time Mode Device Driver
+ *
+ * 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2008, 2009
+ *
+ * Author: Keith Mannthey <kmannth@us.ibm.com>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/sysdev.h>
+#include <asm/byteorder.h>
+#include "rtl.h"
+
+static spinlock_t rtl_lock;
+static void __iomem *rtl_table;
+static void __iomem *edba_map;
+
+static int ibm_rtl_write(u8 value)
+{
+ int count = 0, ret = 0;
+ u32 cmd_prt_value, cmd_port_addr;
+
+ if ((value != RTL_ENABLE) && (value != RTL_DISABLE))
+ return -EINVAL;
+
+ spin_lock(&rtl_lock);
+
+ if (readb(rtl_table+RTL_STATE) != value) {
+ writeb(value, (rtl_table+RTL_CMD));
+
+ /* Trigger the command to be processed*/
+ cmd_prt_value = readw(rtl_table + RTL_CMD_PORT_VALUE);
+ cmd_port_addr = readw(rtl_table + RTL_CMD_PORT_ADDR);
+ outb(cmd_prt_value, cmd_port_addr);
+
+ /* Wait for the command to finish */
+ while (readb(rtl_table+RTL_CMD)) {
+ mdelay(10);
+ if (count++ > 10000) {
+ printk(KERN_ERR "IBM_RTL: Hardware not "
+ "responding to mode switch request\n");
+ spin_unlock(&rtl_lock);
+ return -EIO;
+ }
+ }
+
+ if (readb(rtl_table + RTL_CMD_STATUS))
+ ret = -EIO;
+ }
+
+ spin_unlock(&rtl_lock);
+
+ return ret;
+}
+
+static ssize_t rtl_show_version(struct sysdev_class *dev, char *buf)
+{
+ return sprintf(buf, "%d\n", (int) readb(rtl_table+RTL_VERSION));
+}
+
+static ssize_t rtl_show_state(struct sysdev_class *dev, char *buf)
+{
+ return sprintf(buf, "%d\n", readb(rtl_table+RTL_STATE));
+}
+
+static ssize_t rtl_set_state(struct sysdev_class *dev, const char *buf,
+ size_t size)
+{
+ ssize_t ret;
+
+ if (size != 2)
+ return -EINVAL;
+
+ switch (buf[0]) {
+ case '0':
+ ret = ibm_rtl_write(RTL_DISABLE);
+ break;
+ case '1':
+ ret = ibm_rtl_write(RTL_ENABLE);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ if (ret >= 0)
+ ret = size;
+
+ return ret;
+}
+
+static struct sysdev_class class_rtl = {
+ .name = "ibm_rtl",
+};
+
+static SYSDEV_CLASS_ATTR(version, S_IRUGO, rtl_show_version, NULL);
+static SYSDEV_CLASS_ATTR(state, 0600, rtl_show_state, rtl_set_state);
+
+static struct sysdev_class_attribute *rtl_attributes[] = {
+ &attr_version,
+ &attr_state,
+ NULL
+};
+
+static int rtl_setup_sysfs(void)
+{
+ int ret, i;
+
+ ret = sysdev_class_register(&class_rtl);
+
+ if (!ret) {
+ for (i = 0; rtl_attributes[i]; i++)
+ sysdev_class_create_file(&class_rtl, rtl_attributes[i]);
+ }
+ return ret;
+}
+
+static void rtl_teardown_sysfs(void)
+{
+ int i;
+
+ for (i = 0; rtl_attributes[i]; i++)
+ sysdev_class_remove_file(&class_rtl, rtl_attributes[i]);
+
+ sysdev_class_unregister(&class_rtl);
+ return;
+}
+
+/* Only allow the modules to load if the _RTL_ table can be found */
+int init_module(void)
+{
+ unsigned long ebda_size, ebda_addr;
+ unsigned int ebda_kb;
+ u32 *table;
+ int ret;
+
+ /* Get the address for the Extende Biso Data Area */
+ ebda_addr = *(u16 *) phys_to_virt(EDBA_ADDR);
+ ebda_addr <<= 4;
+ edba_map = ioremap(ebda_addr, 4);
+ if (!edba_map)
+ return -ENOMEM;
+
+ /* First word in the EDBA is the Size in KB */
+ ebda_kb = *(u32 *) edba_map;
+ ebda_size = ebda_kb*1024;
+ iounmap(edba_map);
+
+ /* Remap the whole table */
+ edba_map = ioremap(ebda_addr, ebda_size);
+ if (!edba_map)
+ return -ENOMEM;
+
+ for (table = (u32 *) edba_map ; \
+ table < (u32 *) edba_map + ebda_size/4; table++)
+ if (*table == RTL_MAGIC_IDENT) {
+ rtl_table = table;
+ ret = rtl_setup_sysfs();
+ return ret;
+ }
+
+ ret = -ENODEV;
+ iounmap(edba_map);
+ return ret;
+}
+
+void cleanup_module(void)
+{
+ rtl_teardown_sysfs();
+ iounmap(edba_map);
+}
+
+MODULE_LICENSE("GPL");
diff -urN linux-2.6.32/drivers/misc/ibmrtl/Makefile linux-2.6.32-rtl/drivers/misc/ibmrtl/Makefile
--- linux-2.6.32/drivers/misc/ibmrtl/Makefile 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.32-rtl/drivers/misc/ibmrtl/Makefile 2009-12-11 10:24:23.000000000 -0800
@@ -0,0 +1 @@
+obj-$(CONFIG_IBM_RTL) := ibm_rtl.o
diff -urN linux-2.6.32/drivers/misc/ibmrtl/rtl.h linux-2.6.32-rtl/drivers/misc/ibmrtl/rtl.h
--- linux-2.6.32/drivers/misc/ibmrtl/rtl.h 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.32-rtl/drivers/misc/ibmrtl/rtl.h 2009-12-11 10:24:23.000000000 -0800
@@ -0,0 +1,27 @@
+#include <linux/io.h>
+
+/* The RTL table looks something like
+ u8 signature[5];
+ u8 version;
+ u8 RT_Status;
+ u8 Command;
+ u8 CommandStatus;
+ u8 CMDAddressType;
+ u8 CmdGranularity;
+ u8 CmdOffset;
+ u16 Reserve1;
+ u8 CmdPortAddress[4];
+ u8 CmdPortValue[4];
+*/
+#define RTL_TABLE_SIZE 0x16
+#define RTL_MAGIC_IDENT (('L'<<24)|('T'<<16)|('R'<<8)|'_')
+#define RTL_VERSION 0x5
+#define RTL_STATE 0x6
+#define RTL_CMD 0x7
+#define RTL_CMD_STATUS 0x8
+#define RTL_CMD_PORT_ADDR 0xE
+#define RTL_CMD_PORT_VALUE 0x12
+
+#define EDBA_ADDR 0x40E
+#define RTL_ENABLE 1
+#define RTL_DISABLE 2
diff -urN linux-2.6.32/drivers/misc/Kconfig linux-2.6.32-rtl/drivers/misc/Kconfig
--- linux-2.6.32/drivers/misc/Kconfig 2009-12-02 19:51:21.000000000 -0800
+++ linux-2.6.32-rtl/drivers/misc/Kconfig 2009-12-11 10:24:23.000000000 -0800
@@ -76,6 +76,22 @@
information on the specific driver level and support statement
for your IBM server.

+config IBM_RTL
+ tristate "Device driver to enable IBM PRTL support"
+ depends on X86_MPPARSE && PCI && EXPERIMENTAL
+ ---help---
+ Enable support for IBM Premium Real Time Mode (PRTM).
+ This module will allow you the enter and exit PRTM in the BIOS via
+ sysfs on platforms that support this feature. System in PRTM will
+ not receive cpu generated SMIs for recoverable errors. Use of this
+ feature without proper support may void your hardware warranty.
+
+ If the proper bios support is found the driver will load and create
+ /sys/devices/system/ibm_rtl/. The "state" variable will indicate
+ weather or not the BIOS is in PRTM.
+ state = 0 (BIOS SMI's on)
+ state = 1 (BIOS SMI's off)
+
config PHANTOM
tristate "Sensable PHANToM (PCI)"
depends on PCI
diff -urN linux-2.6.32/drivers/misc/Makefile linux-2.6.32-rtl/drivers/misc/Makefile
--- linux-2.6.32/drivers/misc/Makefile 2009-12-02 19:51:21.000000000 -0800
+++ linux-2.6.32-rtl/drivers/misc/Makefile 2009-12-11 10:24:23.000000000 -0800
@@ -3,6 +3,7 @@
#

obj-$(CONFIG_IBM_ASM) += ibmasm/
+obj-$(CONFIG_IBM_RTL) += ibmrtl/
obj-$(CONFIG_HDPU_FEATURES) += hdpuftrs/
obj-$(CONFIG_ATMEL_PWM) += atmel_pwm.o
obj-$(CONFIG_ATMEL_SSC) += atmel-ssc.o



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