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
  21 #include <asm/geode.h>
  22 #include <asm/setup.h>
  23 #include <asm/olpc.h>
  24
  25 #ifdef CONFIG_OPEN_FIRMWARE
  26 #include <asm/ofw.h>
  27 #endif
  28
  29 struct olpc_platform_t olpc_platform_info;
  30 EXPORT_SYMBOL_GPL(olpc_platform_info);
  31
  32 static DEFINE_SPINLOCK(ec_lock);
  33
  34 /* what the timeout *should* be (in ms) */
  35 #define EC_BASE_TIMEOUT 20
  36
  37 /* the timeout that bugs in the EC might force us to actually use */
  38 static int ec_timeout = EC_BASE_TIMEOUT;
  39
  40 static int __init olpc_ec_timeout_set(char *str)
  41 {
  42         if (get_option(&str, &ec_timeout) != 1) {
  43                 ec_timeout = EC_BASE_TIMEOUT;
  44                 printk(KERN_ERR "olpc-ec:  invalid argument to "
  45                                 "'olpc_ec_timeout=', ignoring!\n");
  46         }
  47         printk(KERN_DEBUG "olpc-ec:  using %d ms delay for EC commands.\n",
  48                         ec_timeout);
  49         return 1;
  50 }
  51 __setup("olpc_ec_timeout=", olpc_ec_timeout_set);
  52
  53 /*
  54  * These {i,o}bf_status functions return whether the buffers are full or not.
  55  */
  56
  57 static inline unsigned int ibf_status(unsigned int port)
  58 {
  59         return !!(inb(port) & 0x02);
  60 }
  61
  62 static inline unsigned int obf_status(unsigned int port)
  63 {
  64         return inb(port) & 0x01;
  65 }
  66
  67 #define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d))
  68 static int __wait_on_ibf(unsigned int line, unsigned int port, int desired)
  69 {
  70         unsigned int timeo;
  71         int state = ibf_status(port);
  72
  73         for (timeo = ec_timeout; state != desired && timeo; timeo--) {
  74                 mdelay(1);
  75                 state = ibf_status(port);
  76         }
  77
  78         if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
  79                         timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
  80                 printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for IBF!\n",
  81                                 line, ec_timeout - timeo);
  82         }
  83
  84         return !(state == desired);
  85 }
  86
  87 #define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d))
  88 static int __wait_on_obf(unsigned int line, unsigned int port, int desired)
  89 {
  90         unsigned int timeo;
  91         int state = obf_status(port);
  92
  93         for (timeo = ec_timeout; state != desired && timeo; timeo--) {
  94                 mdelay(1);
  95                 state = obf_status(port);
  96         }
  97
  98         if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
  99                         timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
 100                 printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for OBF!\n",
 101                                 line, ec_timeout - timeo);
 102         }
 103
 104         return !(state == desired);
 105 }
 106
 107 /*
 108  * This allows the kernel to run Embedded Controller commands.  The EC is
 109  * documented at <http://wiki.laptop.org/go/Embedded_controller>, and the
 110  * available EC commands are here:
 111  * <http://wiki.laptop.org/go/Ec_specification>.  Unfortunately, while
 112  * OpenFirmware's source is available, the EC's is not.
 113  */
 114 int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
 115                 unsigned char *outbuf,  size_t outlen)
 116 {
 117         unsigned long flags;
 118         int ret = -EIO;
 119         int i;
 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         printk(KERN_DEBUG "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                         printk(KERN_DEBUG "olpc-ec:  sending cmd arg 0x%x\n",
 166                                         inbuf[i]);
 167                         outb(inbuf[i], 0x68);
 168                 }
 169         }
 170         if (outbuf && outlen) {
 171                 /* read data from EC */
 172                 for (i = 0; i < outlen; i++) {
 173                         if (wait_on_obf(0x6c, 1)) {
 174                                 printk(KERN_ERR "olpc-ec:  timeout waiting for"
 175                                                 " EC to provide data!\n");
 176                                 goto restart;
 177                         }
 178                         outbuf[i] = inb(0x68);
 179                         printk(KERN_DEBUG "olpc-ec:  received 0x%x\n",
 180                                         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 #ifdef CONFIG_OPEN_FIRMWARE
 192 static void __init platform_detect(void)
 193 {
 194         size_t propsize;
 195         __be32 rev;
 196
 197         if (ofw("getprop", 4, 1, NULL, "board-revision-int", &rev, 4,
 198                         &propsize) || propsize != 4) {
 199                 printk(KERN_ERR "ofw: getprop call failed!\n");
 200                 rev = cpu_to_be32(0);
 201         }
 202         olpc_platform_info.boardrev = be32_to_cpu(rev);
 203 }
 204 #else
 205 static void __init platform_detect(void)
 206 {
 207         /* stopgap until OFW support is added to the kernel */
 208         olpc_platform_info.boardrev = olpc_board(0xc2);
 209 }
 210 #endif
 211
 212 static int __init olpc_init(void)
 213 {
 214         unsigned char *romsig;
 215
 216         /* The ioremap check is dangerous; limit what we run it on */
 217         if (!is_geode() || cs5535_has_vsa2())
 218                 return 0;
 219
 220         spin_lock_init(&ec_lock);
 221
 222         romsig = ioremap(0xffffffc0, 16);
 223         if (!romsig)
 224                 return 0;
 225
 226         if (strncmp(romsig, "CL1   Q", 7))
 227                 goto unmap;
 228         if (strncmp(romsig+6, romsig+13, 3)) {
 229                 printk(KERN_INFO "OLPC BIOS signature looks invalid.  "
 230                                 "Assuming not OLPC\n");
 231                 goto unmap;
 232         }
 233
 234         printk(KERN_INFO "OLPC board with OpenFirmware %.16s\n", romsig);
 235         olpc_platform_info.flags |= OLPC_F_PRESENT;
 236
 237         /* get the platform revision */
 238         platform_detect();
 239
 240         /* assume B1 and above models always have a DCON */
 241         if (olpc_board_at_least(olpc_board(0xb1)))
 242                 olpc_platform_info.flags |= OLPC_F_DCON;
 243
 244         /* get the EC revision */
 245         olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
 246                         (unsigned char *) &olpc_platform_info.ecver, 1);
 247
 248 #ifdef CONFIG_PCI_OLPC
 249         /* If the VSA exists let it emulate PCI, if not emulate in kernel */
 250         if (!cs5535_has_vsa2())
 251                 x86_init.pci.arch_init = pci_olpc_init;
 252 #endif
 253
 254         printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n",
 255                         ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
 256                         olpc_platform_info.boardrev >> 4,
 257                         olpc_platform_info.ecver);
 258
 259 unmap:
 260         iounmap(romsig);
 261         return 0;
 262 }
 263
 264 postcore_initcall(olpc_init);