328 lines
8.1 KiB
C
328 lines
8.1 KiB
C
/*
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* IBM Real-Time Linux driver
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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 this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) IBM Corporation, 2010
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*
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* Author: Keith Mannthey <kmannth@us.ibm.com>
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* Vernon Mauery <vernux@us.ibm.com>
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*
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/io.h>
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#include <linux/dmi.h>
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#include <linux/efi.h>
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#include <linux/mutex.h>
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#include <asm/bios_ebda.h>
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#include <linux/io-64-nonatomic-lo-hi.h>
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static bool force;
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module_param(force, bool, 0);
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MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");
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static bool debug;
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module_param(debug, bool, 0644);
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MODULE_PARM_DESC(debug, "Show debug output");
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Keith Mannthey <kmmanth@us.ibm.com>");
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MODULE_AUTHOR("Vernon Mauery <vernux@us.ibm.com>");
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#define RTL_ADDR_TYPE_IO 1
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#define RTL_ADDR_TYPE_MMIO 2
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#define RTL_CMD_ENTER_PRTM 1
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#define RTL_CMD_EXIT_PRTM 2
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/* The RTL table as presented by the EBDA: */
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struct ibm_rtl_table {
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char signature[5]; /* signature should be "_RTL_" */
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u8 version;
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u8 rt_status;
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u8 command;
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u8 command_status;
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u8 cmd_address_type;
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u8 cmd_granularity;
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u8 cmd_offset;
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u16 reserve1;
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u32 cmd_port_address; /* platform dependent address */
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u32 cmd_port_value; /* platform dependent value */
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} __attribute__((packed));
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/* to locate "_RTL_" signature do a masked 5-byte integer compare */
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#define RTL_SIGNATURE 0x0000005f4c54525fULL
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#define RTL_MASK 0x000000ffffffffffULL
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#define RTL_DEBUG(fmt, ...) \
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do { \
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if (debug) \
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pr_info(fmt, ##__VA_ARGS__); \
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} while (0)
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static DEFINE_MUTEX(rtl_lock);
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static struct ibm_rtl_table __iomem *rtl_table;
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static void __iomem *ebda_map;
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static void __iomem *rtl_cmd_addr;
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static u8 rtl_cmd_type;
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static u8 rtl_cmd_width;
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static void __iomem *rtl_port_map(phys_addr_t addr, unsigned long len)
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{
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if (rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
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return ioremap(addr, len);
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return ioport_map(addr, len);
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}
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static void rtl_port_unmap(void __iomem *addr)
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{
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if (addr && rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
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iounmap(addr);
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else
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ioport_unmap(addr);
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}
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static int ibm_rtl_write(u8 value)
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{
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int ret = 0, count = 0;
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static u32 cmd_port_val;
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RTL_DEBUG("%s(%d)\n", __func__, value);
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value = value == 1 ? RTL_CMD_ENTER_PRTM : RTL_CMD_EXIT_PRTM;
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mutex_lock(&rtl_lock);
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if (ioread8(&rtl_table->rt_status) != value) {
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iowrite8(value, &rtl_table->command);
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switch (rtl_cmd_width) {
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case 8:
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cmd_port_val = ioread8(&rtl_table->cmd_port_value);
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RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
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iowrite8((u8)cmd_port_val, rtl_cmd_addr);
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break;
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case 16:
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cmd_port_val = ioread16(&rtl_table->cmd_port_value);
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RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
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iowrite16((u16)cmd_port_val, rtl_cmd_addr);
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break;
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case 32:
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cmd_port_val = ioread32(&rtl_table->cmd_port_value);
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RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
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iowrite32(cmd_port_val, rtl_cmd_addr);
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break;
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}
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while (ioread8(&rtl_table->command)) {
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msleep(10);
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if (count++ > 500) {
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pr_err("Hardware not responding to "
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"mode switch request\n");
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ret = -EIO;
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break;
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}
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}
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if (ioread8(&rtl_table->command_status)) {
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RTL_DEBUG("command_status reports failed command\n");
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ret = -EIO;
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}
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}
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mutex_unlock(&rtl_lock);
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return ret;
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}
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static ssize_t rtl_show_version(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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return sprintf(buf, "%d\n", (int)ioread8(&rtl_table->version));
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}
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static ssize_t rtl_show_state(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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return sprintf(buf, "%d\n", ioread8(&rtl_table->rt_status));
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}
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static ssize_t rtl_set_state(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t count)
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{
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ssize_t ret;
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if (count < 1 || count > 2)
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return -EINVAL;
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switch (buf[0]) {
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case '0':
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ret = ibm_rtl_write(0);
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break;
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case '1':
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ret = ibm_rtl_write(1);
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break;
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default:
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ret = -EINVAL;
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}
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if (ret >= 0)
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ret = count;
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return ret;
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}
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static struct bus_type rtl_subsys = {
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.name = "ibm_rtl",
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.dev_name = "ibm_rtl",
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};
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static DEVICE_ATTR(version, S_IRUGO, rtl_show_version, NULL);
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static DEVICE_ATTR(state, 0600, rtl_show_state, rtl_set_state);
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static struct device_attribute *rtl_attributes[] = {
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&dev_attr_version,
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&dev_attr_state,
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NULL
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};
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static int rtl_setup_sysfs(void) {
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int ret, i;
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ret = subsys_system_register(&rtl_subsys, NULL);
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if (!ret) {
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for (i = 0; rtl_attributes[i]; i ++)
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device_create_file(rtl_subsys.dev_root, rtl_attributes[i]);
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}
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return ret;
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}
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static void rtl_teardown_sysfs(void) {
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int i;
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for (i = 0; rtl_attributes[i]; i ++)
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device_remove_file(rtl_subsys.dev_root, rtl_attributes[i]);
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bus_unregister(&rtl_subsys);
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}
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static struct dmi_system_id __initdata ibm_rtl_dmi_table[] = {
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{ \
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.matches = { \
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DMI_MATCH(DMI_SYS_VENDOR, "IBM"), \
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}, \
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},
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{ }
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};
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static int __init ibm_rtl_init(void) {
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unsigned long ebda_addr, ebda_size;
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unsigned int ebda_kb;
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int ret = -ENODEV, i;
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if (force)
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pr_warn("module loaded by force\n");
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/* first ensure that we are running on IBM HW */
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else if (efi_enabled(EFI_BOOT) || !dmi_check_system(ibm_rtl_dmi_table))
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return -ENODEV;
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/* Get the address for the Extended BIOS Data Area */
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ebda_addr = get_bios_ebda();
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if (!ebda_addr) {
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RTL_DEBUG("no BIOS EBDA found\n");
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return -ENODEV;
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}
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ebda_map = ioremap(ebda_addr, 4);
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if (!ebda_map)
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return -ENOMEM;
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/* First word in the EDBA is the Size in KB */
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ebda_kb = ioread16(ebda_map);
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RTL_DEBUG("EBDA is %d kB\n", ebda_kb);
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if (ebda_kb == 0)
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goto out;
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iounmap(ebda_map);
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ebda_size = ebda_kb*1024;
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/* Remap the whole table */
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ebda_map = ioremap(ebda_addr, ebda_size);
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if (!ebda_map)
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return -ENOMEM;
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/* search for the _RTL_ signature at the start of the table */
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for (i = 0 ; i < ebda_size/sizeof(unsigned int); i++) {
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struct ibm_rtl_table __iomem * tmp;
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tmp = (struct ibm_rtl_table __iomem *) (ebda_map+i);
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if ((readq(&tmp->signature) & RTL_MASK) == RTL_SIGNATURE) {
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phys_addr_t addr;
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unsigned int plen;
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RTL_DEBUG("found RTL_SIGNATURE at %p\n", tmp);
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rtl_table = tmp;
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/* The address, value, width and offset are platform
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* dependent and found in the ibm_rtl_table */
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rtl_cmd_width = ioread8(&rtl_table->cmd_granularity);
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rtl_cmd_type = ioread8(&rtl_table->cmd_address_type);
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RTL_DEBUG("rtl_cmd_width = %u, rtl_cmd_type = %u\n",
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rtl_cmd_width, rtl_cmd_type);
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addr = ioread32(&rtl_table->cmd_port_address);
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RTL_DEBUG("addr = %#llx\n", (unsigned long long)addr);
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plen = rtl_cmd_width/sizeof(char);
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rtl_cmd_addr = rtl_port_map(addr, plen);
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RTL_DEBUG("rtl_cmd_addr = %p\n", rtl_cmd_addr);
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if (!rtl_cmd_addr) {
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ret = -ENOMEM;
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break;
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}
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ret = rtl_setup_sysfs();
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break;
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}
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}
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out:
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if (ret) {
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iounmap(ebda_map);
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rtl_port_unmap(rtl_cmd_addr);
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}
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return ret;
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}
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static void __exit ibm_rtl_exit(void)
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{
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if (rtl_table) {
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RTL_DEBUG("cleaning up");
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/* do not leave the machine in SMI-free mode */
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ibm_rtl_write(0);
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/* unmap, unlink and remove all traces */
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rtl_teardown_sysfs();
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iounmap(ebda_map);
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rtl_port_unmap(rtl_cmd_addr);
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}
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}
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module_init(ibm_rtl_init);
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module_exit(ibm_rtl_exit);
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