[RFC][Patch] IBM Real-Time "SMI Free" mode driver

From: Keith Mannthey
Date: Tue Feb 10 2009 - 19:52:12 EST

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 (LS21, LS22 and HS21xm blades).

This driver creates a simple sysfs interface to allow a simple entry and
exit from RTL mode in the BIOS.

Signed-off-by: Keith Mannthey <kmannth@xxxxxxxxxx>

---

diff -urN linux-2.6.29-rc3-git7-orig/drivers/misc/ibmrtl/ibm_rtl.c linux-2.6.29-rc3-git7/drivers/misc/ibmrtl/ibm_rtl.c
--- linux-2.6.29-rc3-git7-orig/drivers/misc/ibmrtl/ibm_rtl.c 1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.29-rc3-git7/drivers/misc/ibmrtl/ibm_rtl.c 2009-02-10 13:58:21.000000000 -0500
@@ -0,0 +1,205 @@
+/*
+ * IBM Real Time Linux 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (C) IBM Corporation, 2009
+ *
+ * Author: Keith Mannthey <kmannth@xxxxxxxxxx>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/sysdev.h>
+#include "rtl.h"
+
+static unsigned int table_addr;
+
+int ibm_rtl_write(u8 value)
+{
+ int ret = 0;
+ void __iomem *rtl;
+
+ /* only valid value is 0 and 1 */
+ if (value > 1) {
+ ret = -EINVAL;
+ goto err_out;
+ }
+
+ rtl = ioremap(table_addr, RTL_TABLE_SIZE);
+
+ if (!rtl) {
+ printk(KERN_WARNING "Could not ioremap RTL table\n");
+ ret = -ENOMEM;
+ goto err_out;
+ }
+
+ if (readb(rtl+RTL_STATE) != value) {
+ if (value == 1)
+ writeb(1, (rtl+RTL_CMD));
+ else
+ writeb(2, (rtl+RTL_CMD));
+
+ /*write special command*/
+ outb(bios_to_value(rtl, RTL_CMD_PORT_VALUE),
+ bios_to_value(rtl, RTL_CMD_PORT_ADDR));
+
+ while (readb(rtl+RTL_CMD))
+ msleep(10);
+
+ if (readb(rtl+RTL_CMD_STATUS))
+ ret = -EIO;
+ }
+
+ iounmap(rtl);
+err_out:
+ return ret;
+}
+
+static ssize_t rtl_show_version(struct sysdev_class *dev, char * buf)
+{
+ int ret;
+ void __iomem *rtl;
+
+ rtl = ioremap(table_addr, RTL_TABLE_SIZE);
+
+ if (!rtl) {
+ ret = -ENOMEM;
+ goto err_out;
+ }
+ ret = sprintf(buf, "%d\n", (int)readb(rtl+RTL_VERSION));
+
+ iounmap(rtl);
+err_out:
+ return ret;
+}
+
+static ssize_t rtl_show_state(struct sysdev_class *dev, char *buf)
+{
+ int ret;
+ void __iomem *rtl;
+
+ rtl = ioremap(table_addr, RTL_TABLE_SIZE);
+
+ if (!rtl) {
+ printk(KERN_WARNING "Could not ioremap RTL table\n");
+ ret = -ENOMEM;
+ goto err_out;
+ }
+ ret = sprintf(buf, "%d\n", readb(rtl+RTL_STATE));
+
+ iounmap(rtl);
+err_out:
+ return ret;
+}
+
+static ssize_t rtl_set_state(struct sysdev_class *dev, const char *buf,
+ size_t size)
+{
+ ssize_t ret;
+ switch (buf[0]) {
+ case '0':
+ ret = ibm_rtl_write(0);
+ break;
+ case '1':
+ ret = ibm_rtl_write(1);
+ 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_addr, ebda_size;
+ void __iomem *data, *d;
+ int ret, i;
+
+ /*get the address for the RTL table from the EBDA */
+ ebda_addr = *(unsigned short *)phys_to_virt(0x40E);
+ ebda_addr <<= 4;
+ ebda_size = 64*1024;
+
+ data = ioremap(ebda_addr, ebda_size);
+ d = data;
+ if (!data) {
+ ret = -ENOMEM;
+ goto exit;
+ }
+
+ for (i = 0 ; i < ebda_size/4; i++) {
+ unsigned int *tmp = (unsigned int *) data++;
+ if (*tmp == RTL_MAGIC_IDENT) {
+ table_addr = ebda_addr + i;
+ ret = rtl_setup_sysfs();
+ goto exit;
+ }
+ }
+
+ ret = -ENODEV;
+
+exit:
+ iounmap(d);
+ return ret;
+}
+
+void cleanup_module(void)
+{
+ rtl_teardown_sysfs();
+}
+
+MODULE_LICENSE("GPL");
diff -urN linux-2.6.29-rc3-git7-orig/drivers/misc/ibmrtl/Makefile linux-2.6.29-rc3-git7/drivers/misc/ibmrtl/Makefile
--- linux-2.6.29-rc3-git7-orig/drivers/misc/ibmrtl/Makefile 1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.29-rc3-git7/drivers/misc/ibmrtl/Makefile 2009-02-05 12:38:35.000000000 -0500
@@ -0,0 +1 @@
+obj-$(CONFIG_IBM_RTL) := ibm_rtl.o
diff -urN linux-2.6.29-rc3-git7-orig/drivers/misc/ibmrtl/rtl.h linux-2.6.29-rc3-git7/drivers/misc/ibmrtl/rtl.h
--- linux-2.6.29-rc3-git7-orig/drivers/misc/ibmrtl/rtl.h 1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.29-rc3-git7/drivers/misc/ibmrtl/rtl.h 2009-02-10 13:58:12.000000000 -0500
@@ -0,0 +1,49 @@
+/*
+ * IBM Real Time Linux 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (C) IBM Corporation, 2009
+ *
+ * Author: Keith Mannthey <kmannth@xxxxxxxxxx>
+ *
+ */
+
+#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
+
+/*needed to decode CmdPortAddress and CmdPortValue*/
+#define bios_to_value(rtl, offset) (u32)((readb(rtl+(offset+1)) << 8) + \
+ readb(rtl+offset))
diff -urN linux-2.6.29-rc3-git7-orig/drivers/misc/Kconfig linux-2.6.29-rc3-git7/drivers/misc/Kconfig
--- linux-2.6.29-rc3-git7-orig/drivers/misc/Kconfig 2009-02-05 12:29:22.000000000 -0500
+++ linux-2.6.29-rc3-git7/drivers/misc/Kconfig 2009-02-05 12:45:48.000000000 -0500
@@ -75,6 +75,21 @@
website <http://www.pc.ibm.com/ww/eserver/xseries/serverproven> for
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 && PCI && EXPERIMENTAL
+ ---help---
+ Enable support for IBM Preimium 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 recive cpu generated SMIs for recoverable errors. Use of this
+ feature without proper support may void your hardware warrenty.
+
+ If the proper bios support is found the driver will load and create
+ /sys/devices/system/ibm_rtl/. The "state" varable 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)"
diff -urN linux-2.6.29-rc3-git7-orig/drivers/misc/Makefile linux-2.6.29-rc3-git7/drivers/misc/Makefile
--- linux-2.6.29-rc3-git7-orig/drivers/misc/Makefile 2009-02-05 12:29:22.000000000 -0500
+++ linux-2.6.29-rc3-git7/drivers/misc/Makefile 2009-02-05 12:39:54.000000000 -0500
@@ -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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