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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IBM Real-Time Linux driver
4 *
5 * Copyright (C) IBM Corporation, 2010
6 *
7 * Author: Keith Mannthey <kmannth@us.ibm.com>
8 * Vernon Mauery <vernux@us.ibm.com>
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/kernel.h>
14#include <linux/delay.h>
15#include <linux/module.h>
16#include <linux/io.h>
17#include <linux/dmi.h>
18#include <linux/efi.h>
19#include <linux/mutex.h>
20#include <asm/bios_ebda.h>
21
22#include <linux/io-64-nonatomic-lo-hi.h>
23
24static bool force;
25module_param(force, bool, 0);
26MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");
27
28static bool debug;
29module_param(debug, bool, 0644);
30MODULE_PARM_DESC(debug, "Show debug output");
31
32MODULE_LICENSE("GPL");
33MODULE_AUTHOR("Keith Mannthey <kmmanth@us.ibm.com>");
34MODULE_AUTHOR("Vernon Mauery <vernux@us.ibm.com>");
35
36#define RTL_ADDR_TYPE_IO 1
37#define RTL_ADDR_TYPE_MMIO 2
38
39#define RTL_CMD_ENTER_PRTM 1
40#define RTL_CMD_EXIT_PRTM 2
41
42/* The RTL table as presented by the EBDA: */
43struct ibm_rtl_table {
44 char signature[5]; /* signature should be "_RTL_" */
45 u8 version;
46 u8 rt_status;
47 u8 command;
48 u8 command_status;
49 u8 cmd_address_type;
50 u8 cmd_granularity;
51 u8 cmd_offset;
52 u16 reserve1;
53 u32 cmd_port_address; /* platform dependent address */
54 u32 cmd_port_value; /* platform dependent value */
55} __attribute__((packed));
56
57/* to locate "_RTL_" signature do a masked 5-byte integer compare */
58#define RTL_SIGNATURE 0x0000005f4c54525fULL
59#define RTL_MASK 0x000000ffffffffffULL
60
61#define RTL_DEBUG(fmt, ...) \
62do { \
63 if (debug) \
64 pr_info(fmt, ##__VA_ARGS__); \
65} while (0)
66
67static DEFINE_MUTEX(rtl_lock);
68static struct ibm_rtl_table __iomem *rtl_table;
69static void __iomem *ebda_map;
70static void __iomem *rtl_cmd_addr;
71static u8 rtl_cmd_type;
72static u8 rtl_cmd_width;
73
74static void __iomem *rtl_port_map(phys_addr_t addr, unsigned long len)
75{
76 if (rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
77 return ioremap(addr, len);
78 return ioport_map(addr, len);
79}
80
81static void rtl_port_unmap(void __iomem *addr)
82{
83 if (addr && rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
84 iounmap(addr);
85 else
86 ioport_unmap(addr);
87}
88
89static int ibm_rtl_write(u8 value)
90{
91 int ret = 0, count = 0;
92 u32 cmd_port_val;
93
94 RTL_DEBUG("%s(%d)\n", __func__, value);
95
96 value = value == 1 ? RTL_CMD_ENTER_PRTM : RTL_CMD_EXIT_PRTM;
97
98 mutex_lock(&rtl_lock);
99
100 if (ioread8(&rtl_table->rt_status) != value) {
101 iowrite8(value, &rtl_table->command);
102
103 switch (rtl_cmd_width) {
104 case 8:
105 cmd_port_val = ioread8(&rtl_table->cmd_port_value);
106 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
107 iowrite8((u8)cmd_port_val, rtl_cmd_addr);
108 break;
109 case 16:
110 cmd_port_val = ioread16(&rtl_table->cmd_port_value);
111 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
112 iowrite16((u16)cmd_port_val, rtl_cmd_addr);
113 break;
114 case 32:
115 cmd_port_val = ioread32(&rtl_table->cmd_port_value);
116 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
117 iowrite32(cmd_port_val, rtl_cmd_addr);
118 break;
119 }
120
121 while (ioread8(&rtl_table->command)) {
122 msleep(10);
123 if (count++ > 500) {
124 pr_err("Hardware not responding to "
125 "mode switch request\n");
126 ret = -EIO;
127 break;
128 }
129
130 }
131
132 if (ioread8(&rtl_table->command_status)) {
133 RTL_DEBUG("command_status reports failed command\n");
134 ret = -EIO;
135 }
136 }
137
138 mutex_unlock(&rtl_lock);
139 return ret;
140}
141
142static ssize_t rtl_show_version(struct device *dev,
143 struct device_attribute *attr,
144 char *buf)
145{
146 return sprintf(buf, "%d\n", (int)ioread8(&rtl_table->version));
147}
148
149static ssize_t rtl_show_state(struct device *dev,
150 struct device_attribute *attr,
151 char *buf)
152{
153 return sprintf(buf, "%d\n", ioread8(&rtl_table->rt_status));
154}
155
156static ssize_t rtl_set_state(struct device *dev,
157 struct device_attribute *attr,
158 const char *buf,
159 size_t count)
160{
161 ssize_t ret;
162
163 if (count < 1 || count > 2)
164 return -EINVAL;
165
166 switch (buf[0]) {
167 case '0':
168 ret = ibm_rtl_write(0);
169 break;
170 case '1':
171 ret = ibm_rtl_write(1);
172 break;
173 default:
174 ret = -EINVAL;
175 }
176 if (ret >= 0)
177 ret = count;
178
179 return ret;
180}
181
182static const struct bus_type rtl_subsys = {
183 .name = "ibm_rtl",
184 .dev_name = "ibm_rtl",
185};
186
187static DEVICE_ATTR(version, S_IRUGO, rtl_show_version, NULL);
188static DEVICE_ATTR(state, 0600, rtl_show_state, rtl_set_state);
189
190static struct device_attribute *rtl_attributes[] = {
191 &dev_attr_version,
192 &dev_attr_state,
193 NULL
194};
195
196
197static int rtl_setup_sysfs(void) {
198 int ret, i;
199
200 ret = subsys_system_register(&rtl_subsys, NULL);
201 if (!ret) {
202 struct device *dev_root = bus_get_dev_root(&rtl_subsys);
203
204 if (dev_root) {
205 for (i = 0; rtl_attributes[i]; i ++)
206 device_create_file(dev_root, rtl_attributes[i]);
207 put_device(dev_root);
208 }
209 }
210 return ret;
211}
212
213static void rtl_teardown_sysfs(void) {
214 struct device *dev_root = bus_get_dev_root(&rtl_subsys);
215 int i;
216
217 if (dev_root) {
218 for (i = 0; rtl_attributes[i]; i ++)
219 device_remove_file(dev_root, rtl_attributes[i]);
220 put_device(dev_root);
221 }
222 bus_unregister(&rtl_subsys);
223}
224
225
226static const struct dmi_system_id ibm_rtl_dmi_table[] __initconst = {
227 { \
228 .matches = { \
229 DMI_MATCH(DMI_SYS_VENDOR, "IBM"), \
230 }, \
231 },
232 { }
233};
234
235static int __init ibm_rtl_init(void) {
236 unsigned long ebda_addr, ebda_size;
237 unsigned int ebda_kb;
238 int ret = -ENODEV, i;
239
240 if (force)
241 pr_warn("module loaded by force\n");
242 /* first ensure that we are running on IBM HW */
243 else if (efi_enabled(EFI_BOOT) || !dmi_check_system(ibm_rtl_dmi_table))
244 return -ENODEV;
245
246 /* Get the address for the Extended BIOS Data Area */
247 ebda_addr = get_bios_ebda();
248 if (!ebda_addr) {
249 RTL_DEBUG("no BIOS EBDA found\n");
250 return -ENODEV;
251 }
252
253 ebda_map = ioremap(ebda_addr, 4);
254 if (!ebda_map)
255 return -ENOMEM;
256
257 /* First word in the EDBA is the Size in KB */
258 ebda_kb = ioread16(ebda_map);
259 RTL_DEBUG("EBDA is %d kB\n", ebda_kb);
260
261 if (ebda_kb == 0)
262 goto out;
263
264 iounmap(ebda_map);
265 ebda_size = ebda_kb*1024;
266
267 /* Remap the whole table */
268 ebda_map = ioremap(ebda_addr, ebda_size);
269 if (!ebda_map)
270 return -ENOMEM;
271
272 /* search for the _RTL_ signature at the start of the table */
273 for (i = 0 ; i < ebda_size/sizeof(unsigned int); i++) {
274 struct ibm_rtl_table __iomem * tmp;
275 tmp = (struct ibm_rtl_table __iomem *) (ebda_map+i);
276 if ((readq(&tmp->signature) & RTL_MASK) == RTL_SIGNATURE) {
277 phys_addr_t addr;
278 unsigned int plen;
279 RTL_DEBUG("found RTL_SIGNATURE at %p\n", tmp);
280 rtl_table = tmp;
281 /* The address, value, width and offset are platform
282 * dependent and found in the ibm_rtl_table */
283 rtl_cmd_width = ioread8(&rtl_table->cmd_granularity);
284 rtl_cmd_type = ioread8(&rtl_table->cmd_address_type);
285 RTL_DEBUG("rtl_cmd_width = %u, rtl_cmd_type = %u\n",
286 rtl_cmd_width, rtl_cmd_type);
287 addr = ioread32(&rtl_table->cmd_port_address);
288 RTL_DEBUG("addr = %#llx\n", (unsigned long long)addr);
289 plen = rtl_cmd_width/sizeof(char);
290 rtl_cmd_addr = rtl_port_map(addr, plen);
291 RTL_DEBUG("rtl_cmd_addr = %p\n", rtl_cmd_addr);
292 if (!rtl_cmd_addr) {
293 ret = -ENOMEM;
294 break;
295 }
296 ret = rtl_setup_sysfs();
297 break;
298 }
299 }
300
301out:
302 if (ret) {
303 iounmap(ebda_map);
304 rtl_port_unmap(rtl_cmd_addr);
305 }
306
307 return ret;
308}
309
310static void __exit ibm_rtl_exit(void)
311{
312 if (rtl_table) {
313 RTL_DEBUG("cleaning up");
314 /* do not leave the machine in SMI-free mode */
315 ibm_rtl_write(0);
316 /* unmap, unlink and remove all traces */
317 rtl_teardown_sysfs();
318 iounmap(ebda_map);
319 rtl_port_unmap(rtl_cmd_addr);
320 }
321}
322
323module_init(ibm_rtl_init);
324module_exit(ibm_rtl_exit);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * IBM Real-Time Linux driver
4 *
5 * Copyright (C) IBM Corporation, 2010
6 *
7 * Author: Keith Mannthey <kmannth@us.ibm.com>
8 * Vernon Mauery <vernux@us.ibm.com>
9 */
10
11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13#include <linux/kernel.h>
14#include <linux/delay.h>
15#include <linux/module.h>
16#include <linux/io.h>
17#include <linux/dmi.h>
18#include <linux/efi.h>
19#include <linux/mutex.h>
20#include <asm/bios_ebda.h>
21
22#include <linux/io-64-nonatomic-lo-hi.h>
23
24static bool force;
25module_param(force, bool, 0);
26MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");
27
28static bool debug;
29module_param(debug, bool, 0644);
30MODULE_PARM_DESC(debug, "Show debug output");
31
32MODULE_LICENSE("GPL");
33MODULE_AUTHOR("Keith Mannthey <kmmanth@us.ibm.com>");
34MODULE_AUTHOR("Vernon Mauery <vernux@us.ibm.com>");
35
36#define RTL_ADDR_TYPE_IO 1
37#define RTL_ADDR_TYPE_MMIO 2
38
39#define RTL_CMD_ENTER_PRTM 1
40#define RTL_CMD_EXIT_PRTM 2
41
42/* The RTL table as presented by the EBDA: */
43struct ibm_rtl_table {
44 char signature[5]; /* signature should be "_RTL_" */
45 u8 version;
46 u8 rt_status;
47 u8 command;
48 u8 command_status;
49 u8 cmd_address_type;
50 u8 cmd_granularity;
51 u8 cmd_offset;
52 u16 reserve1;
53 u32 cmd_port_address; /* platform dependent address */
54 u32 cmd_port_value; /* platform dependent value */
55} __attribute__((packed));
56
57/* to locate "_RTL_" signature do a masked 5-byte integer compare */
58#define RTL_SIGNATURE 0x0000005f4c54525fULL
59#define RTL_MASK 0x000000ffffffffffULL
60
61#define RTL_DEBUG(fmt, ...) \
62do { \
63 if (debug) \
64 pr_info(fmt, ##__VA_ARGS__); \
65} while (0)
66
67static DEFINE_MUTEX(rtl_lock);
68static struct ibm_rtl_table __iomem *rtl_table;
69static void __iomem *ebda_map;
70static void __iomem *rtl_cmd_addr;
71static u8 rtl_cmd_type;
72static u8 rtl_cmd_width;
73
74static void __iomem *rtl_port_map(phys_addr_t addr, unsigned long len)
75{
76 if (rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
77 return ioremap(addr, len);
78 return ioport_map(addr, len);
79}
80
81static void rtl_port_unmap(void __iomem *addr)
82{
83 if (addr && rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
84 iounmap(addr);
85 else
86 ioport_unmap(addr);
87}
88
89static int ibm_rtl_write(u8 value)
90{
91 int ret = 0, count = 0;
92 u32 cmd_port_val;
93
94 RTL_DEBUG("%s(%d)\n", __func__, value);
95
96 value = value == 1 ? RTL_CMD_ENTER_PRTM : RTL_CMD_EXIT_PRTM;
97
98 mutex_lock(&rtl_lock);
99
100 if (ioread8(&rtl_table->rt_status) != value) {
101 iowrite8(value, &rtl_table->command);
102
103 switch (rtl_cmd_width) {
104 case 8:
105 cmd_port_val = ioread8(&rtl_table->cmd_port_value);
106 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
107 iowrite8((u8)cmd_port_val, rtl_cmd_addr);
108 break;
109 case 16:
110 cmd_port_val = ioread16(&rtl_table->cmd_port_value);
111 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
112 iowrite16((u16)cmd_port_val, rtl_cmd_addr);
113 break;
114 case 32:
115 cmd_port_val = ioread32(&rtl_table->cmd_port_value);
116 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
117 iowrite32(cmd_port_val, rtl_cmd_addr);
118 break;
119 }
120
121 while (ioread8(&rtl_table->command)) {
122 msleep(10);
123 if (count++ > 500) {
124 pr_err("Hardware not responding to "
125 "mode switch request\n");
126 ret = -EIO;
127 break;
128 }
129
130 }
131
132 if (ioread8(&rtl_table->command_status)) {
133 RTL_DEBUG("command_status reports failed command\n");
134 ret = -EIO;
135 }
136 }
137
138 mutex_unlock(&rtl_lock);
139 return ret;
140}
141
142static ssize_t rtl_show_version(struct device *dev,
143 struct device_attribute *attr,
144 char *buf)
145{
146 return sprintf(buf, "%d\n", (int)ioread8(&rtl_table->version));
147}
148
149static ssize_t rtl_show_state(struct device *dev,
150 struct device_attribute *attr,
151 char *buf)
152{
153 return sprintf(buf, "%d\n", ioread8(&rtl_table->rt_status));
154}
155
156static ssize_t rtl_set_state(struct device *dev,
157 struct device_attribute *attr,
158 const char *buf,
159 size_t count)
160{
161 ssize_t ret;
162
163 if (count < 1 || count > 2)
164 return -EINVAL;
165
166 switch (buf[0]) {
167 case '0':
168 ret = ibm_rtl_write(0);
169 break;
170 case '1':
171 ret = ibm_rtl_write(1);
172 break;
173 default:
174 ret = -EINVAL;
175 }
176 if (ret >= 0)
177 ret = count;
178
179 return ret;
180}
181
182static struct bus_type rtl_subsys = {
183 .name = "ibm_rtl",
184 .dev_name = "ibm_rtl",
185};
186
187static DEVICE_ATTR(version, S_IRUGO, rtl_show_version, NULL);
188static DEVICE_ATTR(state, 0600, rtl_show_state, rtl_set_state);
189
190static struct device_attribute *rtl_attributes[] = {
191 &dev_attr_version,
192 &dev_attr_state,
193 NULL
194};
195
196
197static int rtl_setup_sysfs(void) {
198 int ret, i;
199
200 ret = subsys_system_register(&rtl_subsys, NULL);
201 if (!ret) {
202 for (i = 0; rtl_attributes[i]; i ++)
203 device_create_file(rtl_subsys.dev_root, rtl_attributes[i]);
204 }
205 return ret;
206}
207
208static void rtl_teardown_sysfs(void) {
209 int i;
210 for (i = 0; rtl_attributes[i]; i ++)
211 device_remove_file(rtl_subsys.dev_root, rtl_attributes[i]);
212 bus_unregister(&rtl_subsys);
213}
214
215
216static const struct dmi_system_id ibm_rtl_dmi_table[] __initconst = {
217 { \
218 .matches = { \
219 DMI_MATCH(DMI_SYS_VENDOR, "IBM"), \
220 }, \
221 },
222 { }
223};
224
225static int __init ibm_rtl_init(void) {
226 unsigned long ebda_addr, ebda_size;
227 unsigned int ebda_kb;
228 int ret = -ENODEV, i;
229
230 if (force)
231 pr_warn("module loaded by force\n");
232 /* first ensure that we are running on IBM HW */
233 else if (efi_enabled(EFI_BOOT) || !dmi_check_system(ibm_rtl_dmi_table))
234 return -ENODEV;
235
236 /* Get the address for the Extended BIOS Data Area */
237 ebda_addr = get_bios_ebda();
238 if (!ebda_addr) {
239 RTL_DEBUG("no BIOS EBDA found\n");
240 return -ENODEV;
241 }
242
243 ebda_map = ioremap(ebda_addr, 4);
244 if (!ebda_map)
245 return -ENOMEM;
246
247 /* First word in the EDBA is the Size in KB */
248 ebda_kb = ioread16(ebda_map);
249 RTL_DEBUG("EBDA is %d kB\n", ebda_kb);
250
251 if (ebda_kb == 0)
252 goto out;
253
254 iounmap(ebda_map);
255 ebda_size = ebda_kb*1024;
256
257 /* Remap the whole table */
258 ebda_map = ioremap(ebda_addr, ebda_size);
259 if (!ebda_map)
260 return -ENOMEM;
261
262 /* search for the _RTL_ signature at the start of the table */
263 for (i = 0 ; i < ebda_size/sizeof(unsigned int); i++) {
264 struct ibm_rtl_table __iomem * tmp;
265 tmp = (struct ibm_rtl_table __iomem *) (ebda_map+i);
266 if ((readq(&tmp->signature) & RTL_MASK) == RTL_SIGNATURE) {
267 phys_addr_t addr;
268 unsigned int plen;
269 RTL_DEBUG("found RTL_SIGNATURE at %p\n", tmp);
270 rtl_table = tmp;
271 /* The address, value, width and offset are platform
272 * dependent and found in the ibm_rtl_table */
273 rtl_cmd_width = ioread8(&rtl_table->cmd_granularity);
274 rtl_cmd_type = ioread8(&rtl_table->cmd_address_type);
275 RTL_DEBUG("rtl_cmd_width = %u, rtl_cmd_type = %u\n",
276 rtl_cmd_width, rtl_cmd_type);
277 addr = ioread32(&rtl_table->cmd_port_address);
278 RTL_DEBUG("addr = %#llx\n", (unsigned long long)addr);
279 plen = rtl_cmd_width/sizeof(char);
280 rtl_cmd_addr = rtl_port_map(addr, plen);
281 RTL_DEBUG("rtl_cmd_addr = %p\n", rtl_cmd_addr);
282 if (!rtl_cmd_addr) {
283 ret = -ENOMEM;
284 break;
285 }
286 ret = rtl_setup_sysfs();
287 break;
288 }
289 }
290
291out:
292 if (ret) {
293 iounmap(ebda_map);
294 rtl_port_unmap(rtl_cmd_addr);
295 }
296
297 return ret;
298}
299
300static void __exit ibm_rtl_exit(void)
301{
302 if (rtl_table) {
303 RTL_DEBUG("cleaning up");
304 /* do not leave the machine in SMI-free mode */
305 ibm_rtl_write(0);
306 /* unmap, unlink and remove all traces */
307 rtl_teardown_sysfs();
308 iounmap(ebda_map);
309 rtl_port_unmap(rtl_cmd_addr);
310 }
311}
312
313module_init(ibm_rtl_init);
314module_exit(ibm_rtl_exit);