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25#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26
27#include <linux/kernel.h>
28#include <linux/delay.h>
29#include <linux/module.h>
30#include <linux/io.h>
31#include <linux/dmi.h>
32#include <linux/efi.h>
33#include <linux/mutex.h>
34#include <asm/bios_ebda.h>
35
36#include <linux/io-64-nonatomic-lo-hi.h>
37
38static bool force;
39module_param(force, bool, 0);
40MODULE_PARM_DESC(force, "Force driver load, ignore DMI data");
41
42static bool debug;
43module_param(debug, bool, 0644);
44MODULE_PARM_DESC(debug, "Show debug output");
45
46MODULE_LICENSE("GPL");
47MODULE_AUTHOR("Keith Mannthey <kmmanth@us.ibm.com>");
48MODULE_AUTHOR("Vernon Mauery <vernux@us.ibm.com>");
49
50#define RTL_ADDR_TYPE_IO 1
51#define RTL_ADDR_TYPE_MMIO 2
52
53#define RTL_CMD_ENTER_PRTM 1
54#define RTL_CMD_EXIT_PRTM 2
55
56
57struct ibm_rtl_table {
58 char signature[5];
59 u8 version;
60 u8 rt_status;
61 u8 command;
62 u8 command_status;
63 u8 cmd_address_type;
64 u8 cmd_granularity;
65 u8 cmd_offset;
66 u16 reserve1;
67 u32 cmd_port_address;
68 u32 cmd_port_value;
69} __attribute__((packed));
70
71
72#define RTL_SIGNATURE 0x0000005f4c54525fULL
73#define RTL_MASK 0x000000ffffffffffULL
74
75#define RTL_DEBUG(fmt, ...) \
76do { \
77 if (debug) \
78 pr_info(fmt, ##__VA_ARGS__); \
79} while (0)
80
81static DEFINE_MUTEX(rtl_lock);
82static struct ibm_rtl_table __iomem *rtl_table;
83static void __iomem *ebda_map;
84static void __iomem *rtl_cmd_addr;
85static u8 rtl_cmd_type;
86static u8 rtl_cmd_width;
87
88static void __iomem *rtl_port_map(phys_addr_t addr, unsigned long len)
89{
90 if (rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
91 return ioremap(addr, len);
92 return ioport_map(addr, len);
93}
94
95static void rtl_port_unmap(void __iomem *addr)
96{
97 if (addr && rtl_cmd_type == RTL_ADDR_TYPE_MMIO)
98 iounmap(addr);
99 else
100 ioport_unmap(addr);
101}
102
103static int ibm_rtl_write(u8 value)
104{
105 int ret = 0, count = 0;
106 static u32 cmd_port_val;
107
108 RTL_DEBUG("%s(%d)\n", __func__, value);
109
110 value = value == 1 ? RTL_CMD_ENTER_PRTM : RTL_CMD_EXIT_PRTM;
111
112 mutex_lock(&rtl_lock);
113
114 if (ioread8(&rtl_table->rt_status) != value) {
115 iowrite8(value, &rtl_table->command);
116
117 switch (rtl_cmd_width) {
118 case 8:
119 cmd_port_val = ioread8(&rtl_table->cmd_port_value);
120 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
121 iowrite8((u8)cmd_port_val, rtl_cmd_addr);
122 break;
123 case 16:
124 cmd_port_val = ioread16(&rtl_table->cmd_port_value);
125 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
126 iowrite16((u16)cmd_port_val, rtl_cmd_addr);
127 break;
128 case 32:
129 cmd_port_val = ioread32(&rtl_table->cmd_port_value);
130 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val);
131 iowrite32(cmd_port_val, rtl_cmd_addr);
132 break;
133 }
134
135 while (ioread8(&rtl_table->command)) {
136 msleep(10);
137 if (count++ > 500) {
138 pr_err("Hardware not responding to "
139 "mode switch request\n");
140 ret = -EIO;
141 break;
142 }
143
144 }
145
146 if (ioread8(&rtl_table->command_status)) {
147 RTL_DEBUG("command_status reports failed command\n");
148 ret = -EIO;
149 }
150 }
151
152 mutex_unlock(&rtl_lock);
153 return ret;
154}
155
156static ssize_t rtl_show_version(struct device *dev,
157 struct device_attribute *attr,
158 char *buf)
159{
160 return sprintf(buf, "%d\n", (int)ioread8(&rtl_table->version));
161}
162
163static ssize_t rtl_show_state(struct device *dev,
164 struct device_attribute *attr,
165 char *buf)
166{
167 return sprintf(buf, "%d\n", ioread8(&rtl_table->rt_status));
168}
169
170static ssize_t rtl_set_state(struct device *dev,
171 struct device_attribute *attr,
172 const char *buf,
173 size_t count)
174{
175 ssize_t ret;
176
177 if (count < 1 || count > 2)
178 return -EINVAL;
179
180 switch (buf[0]) {
181 case '0':
182 ret = ibm_rtl_write(0);
183 break;
184 case '1':
185 ret = ibm_rtl_write(1);
186 break;
187 default:
188 ret = -EINVAL;
189 }
190 if (ret >= 0)
191 ret = count;
192
193 return ret;
194}
195
196static struct bus_type rtl_subsys = {
197 .name = "ibm_rtl",
198 .dev_name = "ibm_rtl",
199};
200
201static DEVICE_ATTR(version, S_IRUGO, rtl_show_version, NULL);
202static DEVICE_ATTR(state, 0600, rtl_show_state, rtl_set_state);
203
204static struct device_attribute *rtl_attributes[] = {
205 &dev_attr_version,
206 &dev_attr_state,
207 NULL
208};
209
210
211static int rtl_setup_sysfs(void) {
212 int ret, i;
213
214 ret = subsys_system_register(&rtl_subsys, NULL);
215 if (!ret) {
216 for (i = 0; rtl_attributes[i]; i ++)
217 device_create_file(rtl_subsys.dev_root, rtl_attributes[i]);
218 }
219 return ret;
220}
221
222static void rtl_teardown_sysfs(void) {
223 int i;
224 for (i = 0; rtl_attributes[i]; i ++)
225 device_remove_file(rtl_subsys.dev_root, rtl_attributes[i]);
226 bus_unregister(&rtl_subsys);
227}
228
229
230static struct dmi_system_id __initdata ibm_rtl_dmi_table[] = {
231 { \
232 .matches = { \
233 DMI_MATCH(DMI_SYS_VENDOR, "IBM"), \
234 }, \
235 },
236 { }
237};
238
239static int __init ibm_rtl_init(void) {
240 unsigned long ebda_addr, ebda_size;
241 unsigned int ebda_kb;
242 int ret = -ENODEV, i;
243
244 if (force)
245 pr_warn("module loaded by force\n");
246
247 else if (efi_enabled(EFI_BOOT) || !dmi_check_system(ibm_rtl_dmi_table))
248 return -ENODEV;
249
250
251 ebda_addr = get_bios_ebda();
252 if (!ebda_addr) {
253 RTL_DEBUG("no BIOS EBDA found\n");
254 return -ENODEV;
255 }
256
257 ebda_map = ioremap(ebda_addr, 4);
258 if (!ebda_map)
259 return -ENOMEM;
260
261
262 ebda_kb = ioread16(ebda_map);
263 RTL_DEBUG("EBDA is %d kB\n", ebda_kb);
264
265 if (ebda_kb == 0)
266 goto out;
267
268 iounmap(ebda_map);
269 ebda_size = ebda_kb*1024;
270
271
272 ebda_map = ioremap(ebda_addr, ebda_size);
273 if (!ebda_map)
274 return -ENOMEM;
275
276
277 for (i = 0 ; i < ebda_size/sizeof(unsigned int); i++) {
278 struct ibm_rtl_table __iomem * tmp;
279 tmp = (struct ibm_rtl_table __iomem *) (ebda_map+i);
280 if ((readq(&tmp->signature) & RTL_MASK) == RTL_SIGNATURE) {
281 phys_addr_t addr;
282 unsigned int plen;
283 RTL_DEBUG("found RTL_SIGNATURE at %p\n", tmp);
284 rtl_table = tmp;
285
286
287 rtl_cmd_width = ioread8(&rtl_table->cmd_granularity);
288 rtl_cmd_type = ioread8(&rtl_table->cmd_address_type);
289 RTL_DEBUG("rtl_cmd_width = %u, rtl_cmd_type = %u\n",
290 rtl_cmd_width, rtl_cmd_type);
291 addr = ioread32(&rtl_table->cmd_port_address);
292 RTL_DEBUG("addr = %#llx\n", (unsigned long long)addr);
293 plen = rtl_cmd_width/sizeof(char);
294 rtl_cmd_addr = rtl_port_map(addr, plen);
295 RTL_DEBUG("rtl_cmd_addr = %p\n", rtl_cmd_addr);
296 if (!rtl_cmd_addr) {
297 ret = -ENOMEM;
298 break;
299 }
300 ret = rtl_setup_sysfs();
301 break;
302 }
303 }
304
305out:
306 if (ret) {
307 iounmap(ebda_map);
308 rtl_port_unmap(rtl_cmd_addr);
309 }
310
311 return ret;
312}
313
314static void __exit ibm_rtl_exit(void)
315{
316 if (rtl_table) {
317 RTL_DEBUG("cleaning up");
318
319 ibm_rtl_write(0);
320
321 rtl_teardown_sysfs();
322 iounmap(ebda_map);
323 rtl_port_unmap(rtl_cmd_addr);
324 }
325}
326
327module_init(ibm_rtl_init);
328module_exit(ibm_rtl_exit);
329
