2 * IBM Real-Time Linux driver
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 * Copyright (C) IBM Corporation, 2010
20 * Author: Keith Mannthey <kmannth@us.ibm.com>
21 * Vernon Mauery <vernux@us.ibm.com>
25 #include <linux/kernel.h>
26 #include <linux/delay.h>
27 #include <linux/module.h>
29 #include <linux/sysdev.h>
30 #include <linux/dmi.h>
31 #include <linux/efi.h>
32 #include <linux/mutex.h>
33 #include <asm/bios_ebda.h>
36 module_param(force, bool, 0);
37 MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");
40 module_param(debug, bool, 0644);
41 MODULE_PARM_DESC(debug, "Show debug output");
43 MODULE_LICENSE("GPL");
44 MODULE_AUTHOR("Keith Mannthey <kmmanth@us.ibm.com>");
45 MODULE_AUTHOR("Vernon Mauery <vernux@us.ibm.com>");
47 #define RTL_ADDR_TYPE_IO 1
48 #define RTL_ADDR_TYPE_MMIO 2
50 #define RTL_CMD_ENTER_PRTM 1
51 #define RTL_CMD_EXIT_PRTM 2
53 /* The RTL table as presented by the EBDA: */
54 struct ibm_rtl_table {
55 char signature[5]; /* signature should be "_RTL_" */
64 u32 cmd_port_address; /* platform dependent address */
65 u32 cmd_port_value; /* platform dependent value */
66 } __attribute__((packed));
68 /* to locate "_RTL_" signature do a masked 5-byte integer compare */
69 #define RTL_SIGNATURE 0x0000005f4c54525fULL
70 #define RTL_MASK 0x000000ffffffffffULL
72 #define RTL_DEBUG(A, ...) do { \
74 pr_info("ibm-rtl: " A, ##__VA_ARGS__ ); \
77 static DEFINE_MUTEX(rtl_lock);
78 static struct ibm_rtl_table __iomem *rtl_table;
79 static void __iomem *ebda_map;
80 static void __iomem *rtl_cmd_addr;
81 static u8 rtl_cmd_type;
82 static u8 rtl_cmd_width;
85 static inline __u64 readq(const volatile void __iomem *addr)
87 const volatile u32 __iomem *p = addr;
93 return low + ((u64)high << 32);
97 static void __iomem *rtl_port_map(phys_addr_t addr, unsigned long len)
99 if (rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
100 return ioremap(addr, len);
101 return ioport_map(addr, len);
104 static void rtl_port_unmap(void __iomem *addr)
106 if (addr && rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
112 static int ibm_rtl_write(u8 value)
114 int ret = 0, count = 0;
115 static u32 cmd_port_val;
117 RTL_DEBUG("%s(%d)\n", __FUNCTION__, value);
119 value = value == 1 ? RTL_CMD_ENTER_PRTM : RTL_CMD_EXIT_PRTM;
121 mutex_lock(&rtl_lock);
123 if (ioread8(&rtl_table->rt_status) != value) {
124 iowrite8(value, &rtl_table->command);
126 switch (rtl_cmd_width) {
128 cmd_port_val = ioread8(&rtl_table->cmd_port_value);
129 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
130 iowrite8((u8)cmd_port_val, rtl_cmd_addr);
133 cmd_port_val = ioread16(&rtl_table->cmd_port_value);
134 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
135 iowrite16((u16)cmd_port_val, rtl_cmd_addr);
138 cmd_port_val = ioread32(&rtl_table->cmd_port_value);
139 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
140 iowrite32(cmd_port_val, rtl_cmd_addr);
144 while (ioread8(&rtl_table->command)) {
147 pr_err("ibm-rtl: Hardware not responding to "
148 "mode switch request\n");
155 if (ioread8(&rtl_table->command_status)) {
156 RTL_DEBUG("command_status reports failed command\n");
161 mutex_unlock(&rtl_lock);
165 static ssize_t rtl_show_version(struct sysdev_class * dev,
166 struct sysdev_class_attribute *attr,
169 return sprintf(buf, "%d\n", (int)ioread8(&rtl_table->version));
172 static ssize_t rtl_show_state(struct sysdev_class *dev,
173 struct sysdev_class_attribute *attr,
176 return sprintf(buf, "%d\n", ioread8(&rtl_table->rt_status));
179 static ssize_t rtl_set_state(struct sysdev_class *dev,
180 struct sysdev_class_attribute *attr,
186 if (count < 1 || count > 2)
191 ret = ibm_rtl_write(0);
194 ret = ibm_rtl_write(1);
205 static struct sysdev_class class_rtl = {
209 static SYSDEV_CLASS_ATTR(version, S_IRUGO, rtl_show_version, NULL);
210 static SYSDEV_CLASS_ATTR(state, 0600, rtl_show_state, rtl_set_state);
212 static struct sysdev_class_attribute *rtl_attributes[] = {
219 static int rtl_setup_sysfs(void) {
221 ret = sysdev_class_register(&class_rtl);
224 for (i = 0; rtl_attributes[i]; i ++)
225 sysdev_class_create_file(&class_rtl, rtl_attributes[i]);
230 static void rtl_teardown_sysfs(void) {
232 for (i = 0; rtl_attributes[i]; i ++)
233 sysdev_class_remove_file(&class_rtl, rtl_attributes[i]);
234 sysdev_class_unregister(&class_rtl);
238 static struct dmi_system_id __initdata ibm_rtl_dmi_table[] = {
241 DMI_MATCH(DMI_SYS_VENDOR, "IBM"), \
247 static int __init ibm_rtl_init(void) {
248 unsigned long ebda_addr, ebda_size;
249 unsigned int ebda_kb;
250 int ret = -ENODEV, i;
253 pr_warning("ibm-rtl: module loaded by force\n");
254 /* first ensure that we are running on IBM HW */
255 else if (efi_enabled || !dmi_check_system(ibm_rtl_dmi_table))
258 /* Get the address for the Extended BIOS Data Area */
259 ebda_addr = get_bios_ebda();
261 RTL_DEBUG("no BIOS EBDA found\n");
265 ebda_map = ioremap(ebda_addr, 4);
269 /* First word in the EDBA is the Size in KB */
270 ebda_kb = ioread16(ebda_map);
271 RTL_DEBUG("EBDA is %d kB\n", ebda_kb);
277 ebda_size = ebda_kb*1024;
279 /* Remap the whole table */
280 ebda_map = ioremap(ebda_addr, ebda_size);
284 /* search for the _RTL_ signature at the start of the table */
285 for (i = 0 ; i < ebda_size/sizeof(unsigned int); i++) {
286 struct ibm_rtl_table __iomem * tmp;
287 tmp = (struct ibm_rtl_table __iomem *) (ebda_map+i);
288 if ((readq(&tmp->signature) & RTL_MASK) == RTL_SIGNATURE) {
291 RTL_DEBUG("found RTL_SIGNATURE at %#llx\n", (u64)tmp);
293 /* The address, value, width and offset are platform
294 * dependent and found in the ibm_rtl_table */
295 rtl_cmd_width = ioread8(&rtl_table->cmd_granularity);
296 rtl_cmd_type = ioread8(&rtl_table->cmd_address_type);
297 RTL_DEBUG("rtl_cmd_width = %u, rtl_cmd_type = %u\n",
298 rtl_cmd_width, rtl_cmd_type);
299 addr = ioread32(&rtl_table->cmd_port_address);
300 RTL_DEBUG("addr = %#llx\n", (unsigned long long)addr);
301 plen = rtl_cmd_width/sizeof(char);
302 rtl_cmd_addr = rtl_port_map(addr, plen);
303 RTL_DEBUG("rtl_cmd_addr = %#llx\n", (u64)rtl_cmd_addr);
308 ret = rtl_setup_sysfs();
316 rtl_port_unmap(rtl_cmd_addr);
322 static void __exit ibm_rtl_exit(void)
325 RTL_DEBUG("cleaning up");
326 /* do not leave the machine in SMI-free mode */
328 /* unmap, unlink and remove all traces */
329 rtl_teardown_sysfs();
331 rtl_port_unmap(rtl_cmd_addr);
335 module_init(ibm_rtl_init);
336 module_exit(ibm_rtl_exit);