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 <asm/geode.h>
  21 #include <asm/olpc.h>
  22
  23 #ifdef CONFIG_OPEN_FIRMWARE
  24 #include <asm/ofw.h>
  25 #endif
  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
 119         spin_lock_irqsave(&ec_lock, flags);
 120
 121         /* Clear OBF */
 122         for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++)
 123                 inb(0x68);
 124         if (i == 10) {
 125                 printk(KERN_ERR "olpc-ec:  timeout while attempting to "
 126                                 "clear OBF flag!\n");
 127                 goto err;
 128         }
 129
 130         if (wait_on_ibf(0x6c, 0)) {
 131                 printk(KERN_ERR "olpc-ec:  timeout waiting for EC to "
 132                                 "quiesce!\n");
 133                 goto err;
 134         }
 135
 136 restart:
 137         /*
 138          * Note that if we time out during any IBF checks, that's a failure;
 139          * we have to return.  There's no way for the kernel to clear that.
 140          *
 141          * If we time out during an OBF check, we can restart the command;
 142          * reissuing it will clear the OBF flag, and we should be alright.
 143          * The OBF flag will sometimes misbehave due to what we believe
 144          * is a hardware quirk..
 145          */
 146         printk(KERN_DEBUG "olpc-ec:  running cmd 0x%x\n", cmd);
 147         outb(cmd, 0x6c);
 148
 149         if (wait_on_ibf(0x6c, 0)) {
 150                 printk(KERN_ERR "olpc-ec:  timeout waiting for EC to read "
 151                                 "command!\n");
 152                 goto err;
 153         }
 154
 155         if (inbuf && inlen) {
 156                 /* write data to EC */
 157                 for (i = 0; i < inlen; i++) {
 158                         if (wait_on_ibf(0x6c, 0)) {
 159                                 printk(KERN_ERR "olpc-ec:  timeout waiting for"
 160                                                 " EC accept data!\n");
 161                                 goto err;
 162                         }
 163                         printk(KERN_DEBUG "olpc-ec:  sending cmd arg 0x%x\n",
 164                                         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                                 goto restart;
 175                         }
 176                         outbuf[i] = inb(0x68);
 177                         printk(KERN_DEBUG "olpc-ec:  received 0x%x\n",
 178                                         outbuf[i]);
 179                 }
 180         }
 181
 182         ret = 0;
 183 err:
 184         spin_unlock_irqrestore(&ec_lock, flags);
 185         return ret;
 186 }
 187 EXPORT_SYMBOL_GPL(olpc_ec_cmd);
 188
 189 #ifdef CONFIG_OPEN_FIRMWARE
 190 static void __init platform_detect(void)
 191 {
 192         size_t propsize;
 193         u32 rev;
 194
 195         if (ofw("getprop", 4, 1, NULL, "board-revision-int", &rev, 4,
 196                         &propsize) || propsize != 4) {
 197                 printk(KERN_ERR "ofw: getprop call failed!\n");
 198                 rev = 0;
 199         }
 200         olpc_platform_info.boardrev = be32_to_cpu(rev);
 201 }
 202 #else
 203 static void __init platform_detect(void)
 204 {
 205         /* stopgap until OFW support is added to the kernel */
 206         olpc_platform_info.boardrev = be32_to_cpu(0xc2);
 207 }
 208 #endif
 209
 210 static int __init olpc_init(void)
 211 {
 212         unsigned char *romsig;
 213
 214         /* The ioremap check is dangerous; limit what we run it on */
 215         if (!is_geode() || geode_has_vsa2())
 216                 return 0;
 217
 218         spin_lock_init(&ec_lock);
 219
 220         romsig = ioremap(0xffffffc0, 16);
 221         if (!romsig)
 222                 return 0;
 223
 224         if (strncmp(romsig, "CL1   Q", 7))
 225                 goto unmap;
 226         if (strncmp(romsig+6, romsig+13, 3)) {
 227                 printk(KERN_INFO "OLPC BIOS signature looks invalid.  "
 228                                 "Assuming not OLPC\n");
 229                 goto unmap;
 230         }
 231
 232         printk(KERN_INFO "OLPC board with OpenFirmware %.16s\n", romsig);
 233         olpc_platform_info.flags |= OLPC_F_PRESENT;
 234
 235         /* get the platform revision */
 236         platform_detect();
 237
 238         /* assume B1 and above models always have a DCON */
 239         if (olpc_board_at_least(olpc_board(0xb1)))
 240                 olpc_platform_info.flags |= OLPC_F_DCON;
 241
 242         /* get the EC revision */
 243         olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
 244                         (unsigned char *) &olpc_platform_info.ecver, 1);
 245
 246         /* check to see if the VSA exists */
 247         if (geode_has_vsa2())
 248                 olpc_platform_info.flags |= OLPC_F_VSA;
 249
 250         printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n",
 251                         ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
 252                         olpc_platform_info.boardrev >> 4,
 253                         olpc_platform_info.ecver);
 254
 255 unmap:
 256         iounmap(romsig);
 257         return 0;
 258 }
 259
 260 postcore_initcall(olpc_init);