1 /* 2 * IBM Real-Time Linux driver 3 * 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. 8 * 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. 13 * 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. 17 * 18 * Copyright (C) IBM Corporation, 2010 19 * 20 * Author: Keith Mannthey <kmannth@us.ibm.com> 21 * Vernon Mauery <vernux@us.ibm.com> 22 * 23 */ 24 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 static bool force; 37 module_param(force, bool, 0); 38 MODULE_PARM_DESC(force, "Force driver load, ignore DMI data"); 39 40 static bool debug; 41 module_param(debug, bool, 0644); 42 MODULE_PARM_DESC(debug, "Show debug output"); 43 44 MODULE_LICENSE("GPL"); 45 MODULE_AUTHOR("Keith Mannthey <kmmanth@us.ibm.com>"); 46 MODULE_AUTHOR("Vernon Mauery <vernux@us.ibm.com>"); 47 48 #define RTL_ADDR_TYPE_IO 1 49 #define RTL_ADDR_TYPE_MMIO 2 50 51 #define RTL_CMD_ENTER_PRTM 1 52 #define RTL_CMD_EXIT_PRTM 2 53 54 /* The RTL table as presented by the EBDA: */ 55 struct ibm_rtl_table { 56 char signature[5]; /* signature should be "_RTL_" */ 57 u8 version; 58 u8 rt_status; 59 u8 command; 60 u8 command_status; 61 u8 cmd_address_type; 62 u8 cmd_granularity; 63 u8 cmd_offset; 64 u16 reserve1; 65 u32 cmd_port_address; /* platform dependent address */ 66 u32 cmd_port_value; /* platform dependent value */ 67 } __attribute__((packed)); 68 69 /* to locate "_RTL_" signature do a masked 5-byte integer compare */ 70 #define RTL_SIGNATURE 0x0000005f4c54525fULL 71 #define RTL_MASK 0x000000ffffffffffULL 72 73 #define RTL_DEBUG(fmt, ...) \ 74 do { \ 75 if (debug) \ 76 pr_info(fmt, ##__VA_ARGS__); \ 77 } while (0) 78 79 static DEFINE_MUTEX(rtl_lock); 80 static struct ibm_rtl_table __iomem *rtl_table; 81 static void __iomem *ebda_map; 82 static void __iomem *rtl_cmd_addr; 83 static u8 rtl_cmd_type; 84 static u8 rtl_cmd_width; 85 86 #ifndef readq 87 static inline __u64 readq(const volatile void __iomem *addr) 88 { 89 const volatile u32 __iomem *p = addr; 90 u32 low, high; 91 92 low = readl(p); 93 high = readl(p + 1); 94 95 return low + ((u64)high << 32); 96 } 97 #endif 98 99 static void __iomem *rtl_port_map(phys_addr_t addr, unsigned long len) 100 { 101 if (rtl_cmd_type == RTL_ADDR_TYPE_MMIO) 102 return ioremap(addr, len); 103 return ioport_map(addr, len); 104 } 105 106 static void rtl_port_unmap(void __iomem *addr) 107 { 108 if (addr && rtl_cmd_type == RTL_ADDR_TYPE_MMIO) 109 iounmap(addr); 110 else 111 ioport_unmap(addr); 112 } 113 114 static int ibm_rtl_write(u8 value) 115 { 116 int ret = 0, count = 0; 117 static u32 cmd_port_val; 118 119 RTL_DEBUG("%s(%d)\n", __func__, value); 120 121 value = value == 1 ? RTL_CMD_ENTER_PRTM : RTL_CMD_EXIT_PRTM; 122 123 mutex_lock(&rtl_lock); 124 125 if (ioread8(&rtl_table->rt_status) != value) { 126 iowrite8(value, &rtl_table->command); 127 128 switch (rtl_cmd_width) { 129 case 8: 130 cmd_port_val = ioread8(&rtl_table->cmd_port_value); 131 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val); 132 iowrite8((u8)cmd_port_val, rtl_cmd_addr); 133 break; 134 case 16: 135 cmd_port_val = ioread16(&rtl_table->cmd_port_value); 136 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val); 137 iowrite16((u16)cmd_port_val, rtl_cmd_addr); 138 break; 139 case 32: 140 cmd_port_val = ioread32(&rtl_table->cmd_port_value); 141 RTL_DEBUG("cmd_port_val = %u\n", cmd_port_val); 142 iowrite32(cmd_port_val, rtl_cmd_addr); 143 break; 144 } 145 146 while (ioread8(&rtl_table->command)) { 147 msleep(10); 148 if (count++ > 500) { 149 pr_err("Hardware not responding to " 150 "mode switch request\n"); 151 ret = -EIO; 152 break; 153 } 154 155 } 156 157 if (ioread8(&rtl_table->command_status)) { 158 RTL_DEBUG("command_status reports failed command\n"); 159 ret = -EIO; 160 } 161 } 162 163 mutex_unlock(&rtl_lock); 164 return ret; 165 } 166 167 static ssize_t rtl_show_version(struct device *dev, 168 struct device_attribute *attr, 169 char *buf) 170 { 171 return sprintf(buf, "%d\n", (int)ioread8(&rtl_table->version)); 172 } 173 174 static ssize_t rtl_show_state(struct device *dev, 175 struct device_attribute *attr, 176 char *buf) 177 { 178 return sprintf(buf, "%d\n", ioread8(&rtl_table->rt_status)); 179 } 180 181 static ssize_t rtl_set_state(struct device *dev, 182 struct device_attribute *attr, 183 const char *buf, 184 size_t count) 185 { 186 ssize_t ret; 187 188 if (count < 1 || count > 2) 189 return -EINVAL; 190 191 switch (buf[0]) { 192 case '0': 193 ret = ibm_rtl_write(0); 194 break; 195 case '1': 196 ret = ibm_rtl_write(1); 197 break; 198 default: 199 ret = -EINVAL; 200 } 201 if (ret >= 0) 202 ret = count; 203 204 return ret; 205 } 206 207 static struct bus_type rtl_subsys = { 208 .name = "ibm_rtl", 209 .dev_name = "ibm_rtl", 210 }; 211 212 static DEVICE_ATTR(version, S_IRUGO, rtl_show_version, NULL); 213 static DEVICE_ATTR(state, 0600, rtl_show_state, rtl_set_state); 214 215 static struct device_attribute *rtl_attributes[] = { 216 &dev_attr_version, 217 &dev_attr_state, 218 NULL 219 }; 220 221 222 static int rtl_setup_sysfs(void) { 223 int ret, i; 224 225 ret = subsys_system_register(&rtl_subsys, NULL); 226 if (!ret) { 227 for (i = 0; rtl_attributes[i]; i ++) 228 device_create_file(rtl_subsys.dev_root, rtl_attributes[i]); 229 } 230 return ret; 231 } 232 233 static void rtl_teardown_sysfs(void) { 234 int i; 235 for (i = 0; rtl_attributes[i]; i ++) 236 device_remove_file(rtl_subsys.dev_root, rtl_attributes[i]); 237 bus_unregister(&rtl_subsys); 238 } 239 240 241 static struct dmi_system_id __initdata ibm_rtl_dmi_table[] = { 242 { \ 243 .matches = { \ 244 DMI_MATCH(DMI_SYS_VENDOR, "IBM"), \ 245 }, \ 246 }, 247 { } 248 }; 249 250 static int __init ibm_rtl_init(void) { 251 unsigned long ebda_addr, ebda_size; 252 unsigned int ebda_kb; 253 int ret = -ENODEV, i; 254 255 if (force) 256 pr_warn("module loaded by force\n"); 257 /* first ensure that we are running on IBM HW */ 258 else if (efi_enabled || !dmi_check_system(ibm_rtl_dmi_table)) 259 return -ENODEV; 260 261 /* Get the address for the Extended BIOS Data Area */ 262 ebda_addr = get_bios_ebda(); 263 if (!ebda_addr) { 264 RTL_DEBUG("no BIOS EBDA found\n"); 265 return -ENODEV; 266 } 267 268 ebda_map = ioremap(ebda_addr, 4); 269 if (!ebda_map) 270 return -ENOMEM; 271 272 /* First word in the EDBA is the Size in KB */ 273 ebda_kb = ioread16(ebda_map); 274 RTL_DEBUG("EBDA is %d kB\n", ebda_kb); 275 276 if (ebda_kb == 0) 277 goto out; 278 279 iounmap(ebda_map); 280 ebda_size = ebda_kb*1024; 281 282 /* Remap the whole table */ 283 ebda_map = ioremap(ebda_addr, ebda_size); 284 if (!ebda_map) 285 return -ENOMEM; 286 287 /* search for the _RTL_ signature at the start of the table */ 288 for (i = 0 ; i < ebda_size/sizeof(unsigned int); i++) { 289 struct ibm_rtl_table __iomem * tmp; 290 tmp = (struct ibm_rtl_table __iomem *) (ebda_map+i); 291 if ((readq(&tmp->signature) & RTL_MASK) == RTL_SIGNATURE) { 292 phys_addr_t addr; 293 unsigned int plen; 294 RTL_DEBUG("found RTL_SIGNATURE at %p\n", tmp); 295 rtl_table = tmp; 296 /* The address, value, width and offset are platform 297 * dependent and found in the ibm_rtl_table */ 298 rtl_cmd_width = ioread8(&rtl_table->cmd_granularity); 299 rtl_cmd_type = ioread8(&rtl_table->cmd_address_type); 300 RTL_DEBUG("rtl_cmd_width = %u, rtl_cmd_type = %u\n", 301 rtl_cmd_width, rtl_cmd_type); 302 addr = ioread32(&rtl_table->cmd_port_address); 303 RTL_DEBUG("addr = %#llx\n", (unsigned long long)addr); 304 plen = rtl_cmd_width/sizeof(char); 305 rtl_cmd_addr = rtl_port_map(addr, plen); 306 RTL_DEBUG("rtl_cmd_addr = %p\n", rtl_cmd_addr); 307 if (!rtl_cmd_addr) { 308 ret = -ENOMEM; 309 break; 310 } 311 ret = rtl_setup_sysfs(); 312 break; 313 } 314 } 315 316 out: 317 if (ret) { 318 iounmap(ebda_map); 319 rtl_port_unmap(rtl_cmd_addr); 320 } 321 322 return ret; 323 } 324 325 static void __exit ibm_rtl_exit(void) 326 { 327 if (rtl_table) { 328 RTL_DEBUG("cleaning up"); 329 /* do not leave the machine in SMI-free mode */ 330 ibm_rtl_write(0); 331 /* unmap, unlink and remove all traces */ 332 rtl_teardown_sysfs(); 333 iounmap(ebda_map); 334 rtl_port_unmap(rtl_cmd_addr); 335 } 336 } 337 338 module_init(ibm_rtl_init); 339 module_exit(ibm_rtl_exit); 340