1 /* 2 * Support for the OLPC DCON and OLPC EC access 3 * 4 * Copyright © 2006 Advanced Micro Devices, Inc. 5 * Copyright © 2007-2008 Andres Salomon <dilinger@debian.org> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 */ 12 13 #include <linux/kernel.h> 14 #include <linux/init.h> 15 #include <linux/module.h> 16 #include <linux/delay.h> 17 #include <linux/spinlock.h> 18 #include <linux/io.h> 19 #include <linux/string.h> 20 #include <linux/platform_device.h> 21 #include <linux/of.h> 22 23 #include <asm/geode.h> 24 #include <asm/setup.h> 25 #include <asm/olpc.h> 26 #include <asm/olpc_ofw.h> 27 28 struct olpc_platform_t olpc_platform_info; 29 EXPORT_SYMBOL_GPL(olpc_platform_info); 30 31 static DEFINE_SPINLOCK(ec_lock); 32 33 /* what the timeout *should* be (in ms) */ 34 #define EC_BASE_TIMEOUT 20 35 36 /* the timeout that bugs in the EC might force us to actually use */ 37 static int ec_timeout = EC_BASE_TIMEOUT; 38 39 static int __init olpc_ec_timeout_set(char *str) 40 { 41 if (get_option(&str, &ec_timeout) != 1) { 42 ec_timeout = EC_BASE_TIMEOUT; 43 printk(KERN_ERR "olpc-ec: invalid argument to " 44 "'olpc_ec_timeout=', ignoring!\n"); 45 } 46 printk(KERN_DEBUG "olpc-ec: using %d ms delay for EC commands.\n", 47 ec_timeout); 48 return 1; 49 } 50 __setup("olpc_ec_timeout=", olpc_ec_timeout_set); 51 52 /* 53 * These {i,o}bf_status functions return whether the buffers are full or not. 54 */ 55 56 static inline unsigned int ibf_status(unsigned int port) 57 { 58 return !!(inb(port) & 0x02); 59 } 60 61 static inline unsigned int obf_status(unsigned int port) 62 { 63 return inb(port) & 0x01; 64 } 65 66 #define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d)) 67 static int __wait_on_ibf(unsigned int line, unsigned int port, int desired) 68 { 69 unsigned int timeo; 70 int state = ibf_status(port); 71 72 for (timeo = ec_timeout; state != desired && timeo; timeo--) { 73 mdelay(1); 74 state = ibf_status(port); 75 } 76 77 if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) && 78 timeo < (ec_timeout - EC_BASE_TIMEOUT)) { 79 printk(KERN_WARNING "olpc-ec: %d: waited %u ms for IBF!\n", 80 line, ec_timeout - timeo); 81 } 82 83 return !(state == desired); 84 } 85 86 #define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d)) 87 static int __wait_on_obf(unsigned int line, unsigned int port, int desired) 88 { 89 unsigned int timeo; 90 int state = obf_status(port); 91 92 for (timeo = ec_timeout; state != desired && timeo; timeo--) { 93 mdelay(1); 94 state = obf_status(port); 95 } 96 97 if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) && 98 timeo < (ec_timeout - EC_BASE_TIMEOUT)) { 99 printk(KERN_WARNING "olpc-ec: %d: waited %u ms for OBF!\n", 100 line, ec_timeout - timeo); 101 } 102 103 return !(state == desired); 104 } 105 106 /* 107 * This allows the kernel to run Embedded Controller commands. The EC is 108 * documented at <http://wiki.laptop.org/go/Embedded_controller>, and the 109 * available EC commands are here: 110 * <http://wiki.laptop.org/go/Ec_specification>. Unfortunately, while 111 * OpenFirmware's source is available, the EC's is not. 112 */ 113 int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen, 114 unsigned char *outbuf, size_t outlen) 115 { 116 unsigned long flags; 117 int ret = -EIO; 118 int i; 119 int restarts = 0; 120 121 spin_lock_irqsave(&ec_lock, flags); 122 123 /* Clear OBF */ 124 for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++) 125 inb(0x68); 126 if (i == 10) { 127 printk(KERN_ERR "olpc-ec: timeout while attempting to " 128 "clear OBF flag!\n"); 129 goto err; 130 } 131 132 if (wait_on_ibf(0x6c, 0)) { 133 printk(KERN_ERR "olpc-ec: timeout waiting for EC to " 134 "quiesce!\n"); 135 goto err; 136 } 137 138 restart: 139 /* 140 * Note that if we time out during any IBF checks, that's a failure; 141 * we have to return. There's no way for the kernel to clear that. 142 * 143 * If we time out during an OBF check, we can restart the command; 144 * reissuing it will clear the OBF flag, and we should be alright. 145 * The OBF flag will sometimes misbehave due to what we believe 146 * is a hardware quirk.. 147 */ 148 pr_devel("olpc-ec: running cmd 0x%x\n", cmd); 149 outb(cmd, 0x6c); 150 151 if (wait_on_ibf(0x6c, 0)) { 152 printk(KERN_ERR "olpc-ec: timeout waiting for EC to read " 153 "command!\n"); 154 goto err; 155 } 156 157 if (inbuf && inlen) { 158 /* write data to EC */ 159 for (i = 0; i < inlen; i++) { 160 if (wait_on_ibf(0x6c, 0)) { 161 printk(KERN_ERR "olpc-ec: timeout waiting for" 162 " EC accept data!\n"); 163 goto err; 164 } 165 pr_devel("olpc-ec: sending cmd arg 0x%x\n", inbuf[i]); 166 outb(inbuf[i], 0x68); 167 } 168 } 169 if (outbuf && outlen) { 170 /* read data from EC */ 171 for (i = 0; i < outlen; i++) { 172 if (wait_on_obf(0x6c, 1)) { 173 printk(KERN_ERR "olpc-ec: timeout waiting for" 174 " EC to provide data!\n"); 175 if (restarts++ < 10) 176 goto restart; 177 goto err; 178 } 179 outbuf[i] = inb(0x68); 180 pr_devel("olpc-ec: received 0x%x\n", outbuf[i]); 181 } 182 } 183 184 ret = 0; 185 err: 186 spin_unlock_irqrestore(&ec_lock, flags); 187 return ret; 188 } 189 EXPORT_SYMBOL_GPL(olpc_ec_cmd); 190 191 static bool __init check_ofw_architecture(struct device_node *root) 192 { 193 const char *olpc_arch; 194 int propsize; 195 196 olpc_arch = of_get_property(root, "architecture", &propsize); 197 return propsize == 5 && strncmp("OLPC", olpc_arch, 5) == 0; 198 } 199 200 static u32 __init get_board_revision(struct device_node *root) 201 { 202 int propsize; 203 const __be32 *rev; 204 205 rev = of_get_property(root, "board-revision-int", &propsize); 206 if (propsize != 4) 207 return 0; 208 209 return be32_to_cpu(*rev); 210 } 211 212 static bool __init platform_detect(void) 213 { 214 struct device_node *root = of_find_node_by_path("/"); 215 bool success; 216 217 if (!root) 218 return false; 219 220 success = check_ofw_architecture(root); 221 if (success) { 222 olpc_platform_info.boardrev = get_board_revision(root); 223 olpc_platform_info.flags |= OLPC_F_PRESENT; 224 } 225 226 of_node_put(root); 227 return success; 228 } 229 230 static int __init add_xo1_platform_devices(void) 231 { 232 struct platform_device *pdev; 233 234 pdev = platform_device_register_simple("xo1-rfkill", -1, NULL, 0); 235 if (IS_ERR(pdev)) 236 return PTR_ERR(pdev); 237 238 pdev = platform_device_register_simple("olpc-xo1", -1, NULL, 0); 239 if (IS_ERR(pdev)) 240 return PTR_ERR(pdev); 241 242 return 0; 243 } 244 245 static int __init olpc_init(void) 246 { 247 int r = 0; 248 249 if (!olpc_ofw_present() || !platform_detect()) 250 return 0; 251 252 spin_lock_init(&ec_lock); 253 254 /* assume B1 and above models always have a DCON */ 255 if (olpc_board_at_least(olpc_board(0xb1))) 256 olpc_platform_info.flags |= OLPC_F_DCON; 257 258 /* get the EC revision */ 259 olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0, 260 (unsigned char *) &olpc_platform_info.ecver, 1); 261 262 #ifdef CONFIG_PCI_OLPC 263 /* If the VSA exists let it emulate PCI, if not emulate in kernel. 264 * XO-1 only. */ 265 if (olpc_platform_info.boardrev < olpc_board_pre(0xd0) && 266 !cs5535_has_vsa2()) 267 x86_init.pci.arch_init = pci_olpc_init; 268 #endif 269 270 printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n", 271 ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "", 272 olpc_platform_info.boardrev >> 4, 273 olpc_platform_info.ecver); 274 275 if (olpc_platform_info.boardrev < olpc_board_pre(0xd0)) { /* XO-1 */ 276 r = add_xo1_platform_devices(); 277 if (r) 278 return r; 279 } 280 281 return 0; 282 } 283 284 postcore_initcall(olpc_init); 285