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
;
84 static void __iomem
*rtl_port_map(phys_addr_t addr
, unsigned long len
)
86 if (rtl_cmd_type
== RTL_ADDR_TYPE_MMIO
)
87 return ioremap(addr
, len
);
88 return ioport_map(addr
, len
);
91 static void rtl_port_unmap(void __iomem
*addr
)
93 if (addr
&& rtl_cmd_type
== RTL_ADDR_TYPE_MMIO
)
99 static int ibm_rtl_write(u8 value
)
101 int ret
= 0, count
= 0;
102 static u32 cmd_port_val
;
104 RTL_DEBUG("%s(%d)\n", __FUNCTION__
, value
);
106 value
= value
== 1 ? RTL_CMD_ENTER_PRTM
: RTL_CMD_EXIT_PRTM
;
108 mutex_lock(&rtl_lock
);
110 if (ioread8(&rtl_table
->rt_status
) != value
) {
111 iowrite8(value
, &rtl_table
->command
);
113 switch (rtl_cmd_width
) {
115 cmd_port_val
= ioread8(&rtl_table
->cmd_port_value
);
116 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val
);
117 iowrite8((u8
)cmd_port_val
, rtl_cmd_addr
);
120 cmd_port_val
= ioread16(&rtl_table
->cmd_port_value
);
121 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val
);
122 iowrite16((u16
)cmd_port_val
, rtl_cmd_addr
);
125 cmd_port_val
= ioread32(&rtl_table
->cmd_port_value
);
126 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val
);
127 iowrite32(cmd_port_val
, rtl_cmd_addr
);
131 while (ioread8(&rtl_table
->command
)) {
134 pr_err("ibm-rtl: Hardware not responding to "
135 "mode switch request\n");
142 if (ioread8(&rtl_table
->command_status
)) {
143 RTL_DEBUG("command_status reports failed command\n");
148 mutex_unlock(&rtl_lock
);
152 static ssize_t
rtl_show_version(struct sysdev_class
* dev
,
153 struct sysdev_class_attribute
*attr
,
156 return sprintf(buf
, "%d\n", (int)ioread8(&rtl_table
->version
));
159 static ssize_t
rtl_show_state(struct sysdev_class
*dev
,
160 struct sysdev_class_attribute
*attr
,
163 return sprintf(buf
, "%d\n", ioread8(&rtl_table
->rt_status
));
166 static ssize_t
rtl_set_state(struct sysdev_class
*dev
,
167 struct sysdev_class_attribute
*attr
,
173 if (count
< 1 || count
> 2)
178 ret
= ibm_rtl_write(0);
181 ret
= ibm_rtl_write(1);
192 static struct sysdev_class class_rtl
= {
196 static SYSDEV_CLASS_ATTR(version
, S_IRUGO
, rtl_show_version
, NULL
);
197 static SYSDEV_CLASS_ATTR(state
, 0600, rtl_show_state
, rtl_set_state
);
199 static struct sysdev_class_attribute
*rtl_attributes
[] = {
206 static int rtl_setup_sysfs(void) {
208 ret
= sysdev_class_register(&class_rtl
);
211 for (i
= 0; rtl_attributes
[i
]; i
++)
212 sysdev_class_create_file(&class_rtl
, rtl_attributes
[i
]);
217 static void rtl_teardown_sysfs(void) {
219 for (i
= 0; rtl_attributes
[i
]; i
++)
220 sysdev_class_remove_file(&class_rtl
, rtl_attributes
[i
]);
221 sysdev_class_unregister(&class_rtl
);
225 static struct dmi_system_id __initdata ibm_rtl_dmi_table
[] = {
228 DMI_MATCH(DMI_SYS_VENDOR
, "IBM"), \
234 static int __init
ibm_rtl_init(void) {
235 unsigned long ebda_addr
, ebda_size
;
236 unsigned int ebda_kb
;
237 int ret
= -ENODEV
, i
;
240 pr_warning("ibm-rtl: module loaded by force\n");
241 /* first ensure that we are running on IBM HW */
242 else if (efi_enabled
|| !dmi_check_system(ibm_rtl_dmi_table
))
245 /* Get the address for the Extended BIOS Data Area */
246 ebda_addr
= get_bios_ebda();
248 RTL_DEBUG("no BIOS EBDA found\n");
252 ebda_map
= ioremap(ebda_addr
, 4);
256 /* First word in the EDBA is the Size in KB */
257 ebda_kb
= ioread16(ebda_map
);
258 RTL_DEBUG("EBDA is %d kB\n", ebda_kb
);
264 ebda_size
= ebda_kb
*1024;
266 /* Remap the whole table */
267 ebda_map
= ioremap(ebda_addr
, ebda_size
);
271 /* search for the _RTL_ signature at the start of the table */
272 for (i
= 0 ; i
< ebda_size
/sizeof(unsigned int); i
++) {
273 struct ibm_rtl_table __iomem
* tmp
;
274 tmp
= (struct ibm_rtl_table __iomem
*) (ebda_map
+i
);
275 if ((readq(&tmp
->signature
) & RTL_MASK
) == RTL_SIGNATURE
) {
278 RTL_DEBUG("found RTL_SIGNATURE at %#llx\n", (u64
)tmp
);
280 /* The address, value, width and offset are platform
281 * dependent and found in the ibm_rtl_table */
282 rtl_cmd_width
= ioread8(&rtl_table
->cmd_granularity
);
283 rtl_cmd_type
= ioread8(&rtl_table
->cmd_address_type
);
284 RTL_DEBUG("rtl_cmd_width = %u, rtl_cmd_type = %u\n",
285 rtl_cmd_width
, rtl_cmd_type
);
286 addr
= ioread32(&rtl_table
->cmd_port_address
);
287 RTL_DEBUG("addr = %#llx\n", (unsigned long long)addr
);
288 plen
= rtl_cmd_width
/sizeof(char);
289 rtl_cmd_addr
= rtl_port_map(addr
, plen
);
290 RTL_DEBUG("rtl_cmd_addr = %#llx\n", (u64
)rtl_cmd_addr
);
295 ret
= rtl_setup_sysfs();
303 rtl_port_unmap(rtl_cmd_addr
);
309 static void __exit
ibm_rtl_exit(void)
312 RTL_DEBUG("cleaning up");
313 /* do not leave the machine in SMI-free mode */
315 /* unmap, unlink and remove all traces */
316 rtl_teardown_sysfs();
318 rtl_port_unmap(rtl_cmd_addr
);
322 module_init(ibm_rtl_init
);
323 module_exit(ibm_rtl_exit
);