release/src-rt-6.x.4708/linux/linux-2.6.36/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 #include <asm/olpc_ofw.h>
  25
  26 struct olpc_platform_t olpc_platform_info;
  27 EXPORT_SYMBOL_GPL(olpc_platform_info);
  28
  29 static DEFINE_SPINLOCK(ec_lock);
  30
  31 /* what the timeout *should* be (in ms) */
  32 #define EC_BASE_TIMEOUT 20
  33
  34 /* the timeout that bugs in the EC might force us to actually use */
  35 static int ec_timeout = EC_BASE_TIMEOUT;
  36
  37 static int __init olpc_ec_timeout_set(char *str)
  38 {
  39         if (get_option(&str, &ec_timeout) != 1) {
  40                 ec_timeout = EC_BASE_TIMEOUT;
  41                 printk(KERN_ERR "olpc-ec:  invalid argument to "
  42                                 "'olpc_ec_timeout=', ignoring!\n");
  43         }
  44         printk(KERN_DEBUG "olpc-ec:  using %d ms delay for EC commands.\n",
  45                         ec_timeout);
  46         return 1;
  47 }
  48 __setup("olpc_ec_timeout=", olpc_ec_timeout_set);
  49
  50 /*
  51  * These {i,o}bf_status functions return whether the buffers are full or not.
  52  */
  53
  54 static inline unsigned int ibf_status(unsigned int port)
  55 {
  56         return !!(inb(port) & 0x02);
  57 }
  58
  59 static inline unsigned int obf_status(unsigned int port)
  60 {
  61         return inb(port) & 0x01;
  62 }
  63
  64 #define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d))
  65 static int __wait_on_ibf(unsigned int line, unsigned int port, int desired)
  66 {
  67         unsigned int timeo;
  68         int state = ibf_status(port);
  69
  70         for (timeo = ec_timeout; state != desired && timeo; timeo--) {
  71                 mdelay(1);
  72                 state = ibf_status(port);
  73         }
  74
  75         if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
  76                         timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
  77                 printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for IBF!\n",
  78                                 line, ec_timeout - timeo);
  79         }
  80
  81         return !(state == desired);
  82 }
  83
  84 #define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d))
  85 static int __wait_on_obf(unsigned int line, unsigned int port, int desired)
  86 {
  87         unsigned int timeo;
  88         int state = obf_status(port);
  89
  90         for (timeo = ec_timeout; state != desired && timeo; timeo--) {
  91                 mdelay(1);
  92                 state = obf_status(port);
  93         }
  94
  95         if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
  96                         timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
  97                 printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for OBF!\n",
  98                                 line, ec_timeout - timeo);
  99         }
 100
 101         return !(state == desired);
 102 }
 103
 104 /*
 105  * This allows the kernel to run Embedded Controller commands.  The EC is
 106  * documented at <http://wiki.laptop.org/go/Embedded_controller>, and the
 107  * available EC commands are here:
 108  * <http://wiki.laptop.org/go/Ec_specification>.  Unfortunately, while
 109  * OpenFirmware's source is available, the EC's is not.
 110  */
 111 int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
 112                 unsigned char *outbuf,  size_t outlen)
 113 {
 114         unsigned long flags;
 115         int ret = -EIO;
 116         int i;
 117         int restarts = 0;
 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         pr_devel("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                         pr_devel("olpc-ec:  sending cmd arg 0x%x\n", inbuf[i]);
 164                         outb(inbuf[i], 0x68);
 165                 }
 166         }
 167         if (outbuf && outlen) {
 168                 /* read data from EC */
 169                 for (i = 0; i < outlen; i++) {
 170                         if (wait_on_obf(0x6c, 1)) {
 171                                 printk(KERN_ERR "olpc-ec:  timeout waiting for"
 172                                                 " EC to provide data!\n");
 173                                 if (restarts++ < 10)
 174                                         goto restart;
 175                                 goto err;
 176                         }
 177                         outbuf[i] = inb(0x68);
 178                         pr_devel("olpc-ec:  received 0x%x\n", 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_OLPC_OPENFIRMWARE
 190 static void __init platform_detect(void)
 191 {
 192         size_t propsize;
 193         __be32 rev;
 194         const void *args[] = { NULL, "board-revision-int", &rev, (void *)4 };
 195         void *res[] = { &propsize };
 196
 197         if (olpc_ofw("getprop", args, res) || propsize != 4) {
 198                 printk(KERN_ERR "ofw: getprop call failed!\n");
 199                 rev = cpu_to_be32(0);
 200         }
 201         olpc_platform_info.boardrev = be32_to_cpu(rev);
 202 }
 203 #else
 204 static void __init platform_detect(void)
 205 {
 206         /* stopgap until OFW support is added to the kernel */
 207         olpc_platform_info.boardrev = olpc_board(0xc2);
 208 }
 209 #endif
 210
 211 static int __init olpc_init(void)
 212 {
 213         unsigned char *romsig;
 214
 215         /* The ioremap check is dangerous; limit what we run it on */
 216         if (!is_geode() || cs5535_has_vsa2())
 217                 return 0;
 218
 219         spin_lock_init(&ec_lock);
 220
 221         romsig = ioremap(0xffffffc0, 16);
 222         if (!romsig)
 223                 return 0;
 224
 225         if (strncmp(romsig, "CL1   Q", 7))
 226                 goto unmap;
 227         if (strncmp(romsig+6, romsig+13, 3)) {
 228                 printk(KERN_INFO "OLPC BIOS signature looks invalid.  "
 229                                 "Assuming not OLPC\n");
 230                 goto unmap;
 231         }
 232
 233         printk(KERN_INFO "OLPC board with OpenFirmware %.16s\n", romsig);
 234         olpc_platform_info.flags |= OLPC_F_PRESENT;
 235
 236         /* get the platform revision */
 237         platform_detect();
 238
 239         /* assume B1 and above models always have a DCON */
 240         if (olpc_board_at_least(olpc_board(0xb1)))
 241                 olpc_platform_info.flags |= OLPC_F_DCON;
 242
 243         /* get the EC revision */
 244         olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
 245                         (unsigned char *) &olpc_platform_info.ecver, 1);
 246
 247 #ifdef CONFIG_PCI_OLPC
 248         /* If the VSA exists let it emulate PCI, if not emulate in kernel */
 249         if (!cs5535_has_vsa2())
 250                 x86_init.pci.arch_init = pci_olpc_init;
 251 #endif
 252
 253         printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n",
 254                         ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
 255                         olpc_platform_info.boardrev >> 4,
 256                         olpc_platform_info.ecver);
 257
 258 unmap:
 259         iounmap(romsig);
 260         return 0;
 261 }
 262
 263 postcore_initcall(olpc_init);