arch/x86/kernel/olpc.c

   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
  22 #include <asm/geode.h>
  23 #include <asm/setup.h>
  24 #include <asm/olpc.h>
  25 #include <asm/olpc_ofw.h>
  26
  27 struct olpc_platform_t olpc_platform_info;
  28 EXPORT_SYMBOL_GPL(olpc_platform_info);
  29
  30 static DEFINE_SPINLOCK(ec_lock);
  31
  32 /* what the timeout *should* be (in ms) */
  33 #define EC_BASE_TIMEOUT 20
  34
  35 /* the timeout that bugs in the EC might force us to actually use */
  36 static int ec_timeout = EC_BASE_TIMEOUT;
  37
  38 static int __init olpc_ec_timeout_set(char *str)
  39 {
  40         if (get_option(&str, &ec_timeout) != 1) {
  41                 ec_timeout = EC_BASE_TIMEOUT;
  42                 printk(KERN_ERR "olpc-ec:  invalid argument to "
  43                                 "'olpc_ec_timeout=', ignoring!\n");
  44         }
  45         printk(KERN_DEBUG "olpc-ec:  using %d ms delay for EC commands.\n",
  46                         ec_timeout);
  47         return 1;
  48 }
  49 __setup("olpc_ec_timeout=", olpc_ec_timeout_set);
  50
  51 /*
  52  * These {i,o}bf_status functions return whether the buffers are full or not.
  53  */
  54
  55 static inline unsigned int ibf_status(unsigned int port)
  56 {
  57         return !!(inb(port) & 0x02);
  58 }
  59
  60 static inline unsigned int obf_status(unsigned int port)
  61 {
  62         return inb(port) & 0x01;
  63 }
  64
  65 #define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d))
  66 static int __wait_on_ibf(unsigned int line, unsigned int port, int desired)
  67 {
  68         unsigned int timeo;
  69         int state = ibf_status(port);
  70
  71         for (timeo = ec_timeout; state != desired && timeo; timeo--) {
  72                 mdelay(1);
  73                 state = ibf_status(port);
  74         }
  75
  76         if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
  77                         timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
  78                 printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for IBF!\n",
  79                                 line, ec_timeout - timeo);
  80         }
  81
  82         return !(state == desired);
  83 }
  84
  85 #define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d))
  86 static int __wait_on_obf(unsigned int line, unsigned int port, int desired)
  87 {
  88         unsigned int timeo;
  89         int state = obf_status(port);
  90
  91         for (timeo = ec_timeout; state != desired && timeo; timeo--) {
  92                 mdelay(1);
  93                 state = obf_status(port);
  94         }
  95
  96         if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
  97                         timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
  98                 printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for OBF!\n",
  99                                 line, ec_timeout - timeo);
 100         }
 101
 102         return !(state == desired);
 103 }
 104
 105 /*
 106  * This allows the kernel to run Embedded Controller commands.  The EC is
 107  * documented at <http://wiki.laptop.org/go/Embedded_controller>, and the
 108  * available EC commands are here:
 109  * <http://wiki.laptop.org/go/Ec_specification>.  Unfortunately, while
 110  * OpenFirmware's source is available, the EC's is not.
 111  */
 112 int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
 113                 unsigned char *outbuf,  size_t outlen)
 114 {
 115         unsigned long flags;
 116         int ret = -EIO;
 117         int i;
 118         int restarts = 0;
 119
 120         spin_lock_irqsave(&ec_lock, flags);
 121
 122         /* Clear OBF */
 123         for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++)
 124                 inb(0x68);
 125         if (i == 10) {
 126                 printk(KERN_ERR "olpc-ec:  timeout while attempting to "
 127                                 "clear OBF flag!\n");
 128                 goto err;
 129         }
 130
 131         if (wait_on_ibf(0x6c, 0)) {
 132                 printk(KERN_ERR "olpc-ec:  timeout waiting for EC to "
 133                                 "quiesce!\n");
 134                 goto err;
 135         }
 136
 137 restart:
 138         /*
 139          * Note that if we time out during any IBF checks, that's a failure;
 140          * we have to return.  There's no way for the kernel to clear that.
 141          *
 142          * If we time out during an OBF check, we can restart the command;
 143          * reissuing it will clear the OBF flag, and we should be alright.
 144          * The OBF flag will sometimes misbehave due to what we believe
 145          * is a hardware quirk..
 146          */
 147         pr_devel("olpc-ec:  running cmd 0x%x\n", cmd);
 148         outb(cmd, 0x6c);
 149
 150         if (wait_on_ibf(0x6c, 0)) {
 151                 printk(KERN_ERR "olpc-ec:  timeout waiting for EC to read "
 152                                 "command!\n");
 153                 goto err;
 154         }
 155
 156         if (inbuf && inlen) {
 157                 /* write data to EC */
 158                 for (i = 0; i < inlen; i++) {
 159                         if (wait_on_ibf(0x6c, 0)) {
 160                                 printk(KERN_ERR "olpc-ec:  timeout waiting for"
 161                                                 " EC accept data!\n");
 162                                 goto err;
 163                         }
 164                         pr_devel("olpc-ec:  sending cmd arg 0x%x\n", inbuf[i]);
 165                         outb(inbuf[i], 0x68);
 166                 }
 167         }
 168         if (outbuf && outlen) {
 169                 /* read data from EC */
 170                 for (i = 0; i < outlen; i++) {
 171                         if (wait_on_obf(0x6c, 1)) {
 172                                 printk(KERN_ERR "olpc-ec:  timeout waiting for"
 173                                                 " EC to provide data!\n");
 174                                 if (restarts++ < 10)
 175                                         goto restart;
 176                                 goto err;
 177                         }
 178                         outbuf[i] = inb(0x68);
 179                         pr_devel("olpc-ec:  received 0x%x\n", outbuf[i]);
 180                 }
 181         }
 182
 183         ret = 0;
 184 err:
 185         spin_unlock_irqrestore(&ec_lock, flags);
 186         return ret;
 187 }
 188 EXPORT_SYMBOL_GPL(olpc_ec_cmd);
 189
 190 static bool __init check_ofw_architecture(void)
 191 {
 192         size_t propsize;
 193         char olpc_arch[5];
 194         const void *args[] = { NULL, "architecture", olpc_arch, (void *)5 };
 195         void *res[] = { &propsize };
 196
 197         if (olpc_ofw("getprop", args, res)) {
 198                 printk(KERN_ERR "ofw: getprop call failed!\n");
 199                 return false;
 200         }
 201         return propsize == 5 && strncmp("OLPC", olpc_arch, 5) == 0;
 202 }
 203
 204 static u32 __init get_board_revision(void)
 205 {
 206         size_t propsize;
 207         __be32 rev;
 208         const void *args[] = { NULL, "board-revision-int", &rev, (void *)4 };
 209         void *res[] = { &propsize };
 210
 211         if (olpc_ofw("getprop", args, res) || propsize != 4) {
 212                 printk(KERN_ERR "ofw: getprop call failed!\n");
 213                 return cpu_to_be32(0);
 214         }
 215         return be32_to_cpu(rev);
 216 }
 217
 218 static bool __init platform_detect(void)
 219 {
 220         if (!check_ofw_architecture())
 221                 return false;
 222         olpc_platform_info.flags |= OLPC_F_PRESENT;
 223         olpc_platform_info.boardrev = get_board_revision();
 224         return true;
 225 }
 226
 227 static int __init add_xo1_platform_devices(void)
 228 {
 229         struct platform_device *pdev;
 230
 231         pdev = platform_device_register_simple("xo1-rfkill", -1, NULL, 0);
 232         if (IS_ERR(pdev))
 233                 return PTR_ERR(pdev);
 234
 235         pdev = platform_device_register_simple("olpc-xo1", -1, NULL, 0);
 236         if (IS_ERR(pdev))
 237                 return PTR_ERR(pdev);
 238
 239         return 0;
 240 }
 241
 242 static int __init olpc_init(void)
 243 {
 244         int r = 0;
 245
 246         if (!olpc_ofw_present() || !platform_detect())
 247                 return 0;
 248
 249         spin_lock_init(&ec_lock);
 250
 251         /* assume B1 and above models always have a DCON */
 252         if (olpc_board_at_least(olpc_board(0xb1)))
 253                 olpc_platform_info.flags |= OLPC_F_DCON;
 254
 255         /* get the EC revision */
 256         olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
 257                         (unsigned char *) &olpc_platform_info.ecver, 1);
 258
 259 #ifdef CONFIG_PCI_OLPC
 260         /* If the VSA exists let it emulate PCI, if not emulate in kernel.
 261          * XO-1 only. */
 262         if (olpc_platform_info.boardrev < olpc_board_pre(0xd0) &&
 263                         !cs5535_has_vsa2())
 264                 x86_init.pci.arch_init = pci_olpc_init;
 265 #endif
 266
 267         printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n",
 268                         ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
 269                         olpc_platform_info.boardrev >> 4,
 270                         olpc_platform_info.ecver);
 271
 272         if (olpc_platform_info.boardrev < olpc_board_pre(0xd0)) { /* XO-1 */
 273                 r = add_xo1_platform_devices();
 274                 if (r)
 275                         return r;
 276         }
 277
 278         return 0;
 279 }
 280
 281 postcore_initcall(olpc_init);