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         int restarts = 0;
 121
 122         spin_lock_irqsave(&ec_lock, flags);
 123
 124         /* Clear OBF */
 125         for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++)
 126                 inb(0x68);
 127         if (i == 10) {
 128                 printk(KERN_ERR "olpc-ec:  timeout while attempting to "
 129                                 "clear OBF flag!\n");
 130                 goto err;
 131         }
 132
 133         if (wait_on_ibf(0x6c, 0)) {
 134                 printk(KERN_ERR "olpc-ec:  timeout waiting for EC to "
 135                                 "quiesce!\n");
 136                 goto err;
 137         }
 138
 139 restart:
 140         /*
 141          * Note that if we time out during any IBF checks, that's a failure;
 142          * we have to return.  There's no way for the kernel to clear that.
 143          *
 144          * If we time out during an OBF check, we can restart the command;
 145          * reissuing it will clear the OBF flag, and we should be alright.
 146          * The OBF flag will sometimes misbehave due to what we believe
 147          * is a hardware quirk..
 148          */
 149         printk(KERN_DEBUG "olpc-ec:  running cmd 0x%x\n", cmd);
 150         outb(cmd, 0x6c);
 151
 152         if (wait_on_ibf(0x6c, 0)) {
 153                 printk(KERN_ERR "olpc-ec:  timeout waiting for EC to read "
 154                                 "command!\n");
 155                 goto err;
 156         }
 157
 158         if (inbuf && inlen) {
 159                 /* write data to EC */
 160                 for (i = 0; i < inlen; i++) {
 161                         if (wait_on_ibf(0x6c, 0)) {
 162                                 printk(KERN_ERR "olpc-ec:  timeout waiting for"
 163                                                 " EC accept data!\n");
 164                                 goto err;
 165                         }
 166                         printk(KERN_DEBUG "olpc-ec:  sending cmd arg 0x%x\n",
 167                                         inbuf[i]);
 168                         outb(inbuf[i], 0x68);
 169                 }
 170         }
 171         if (outbuf && outlen) {
 172                 /* read data from EC */
 173                 for (i = 0; i < outlen; i++) {
 174                         if (wait_on_obf(0x6c, 1)) {
 175                                 printk(KERN_ERR "olpc-ec:  timeout waiting for"
 176                                                 " EC to provide data!\n");
 177                                 if (restarts++ < 10)
 178                                         goto restart;
 179                                 goto err;
 180                         }
 181                         outbuf[i] = inb(0x68);
 182                         printk(KERN_DEBUG "olpc-ec:  received 0x%x\n",
 183                                         outbuf[i]);
 184                 }
 185         }
 186
 187         ret = 0;
 188 err:
 189         spin_unlock_irqrestore(&ec_lock, flags);
 190         return ret;
 191 }
 192 EXPORT_SYMBOL_GPL(olpc_ec_cmd);
 193
 194 #ifdef CONFIG_OPEN_FIRMWARE
 195 static void __init platform_detect(void)
 196 {
 197         size_t propsize;
 198         __be32 rev;
 199
 200         if (ofw("getprop", 4, 1, NULL, "board-revision-int", &rev, 4,
 201                         &propsize) || propsize != 4) {
 202                 printk(KERN_ERR "ofw: getprop call failed!\n");
 203                 rev = cpu_to_be32(0);
 204         }
 205         olpc_platform_info.boardrev = be32_to_cpu(rev);
 206 }
 207 #else
 208 static void __init platform_detect(void)
 209 {
 210         /* stopgap until OFW support is added to the kernel */
 211         olpc_platform_info.boardrev = olpc_board(0xc2);
 212 }
 213 #endif
 214
 215 static int __init olpc_init(void)
 216 {
 217         unsigned char *romsig;
 218
 219         /* The ioremap check is dangerous; limit what we run it on */
 220         if (!is_geode() || cs5535_has_vsa2())
 221                 return 0;
 222
 223         spin_lock_init(&ec_lock);
 224
 225         romsig = ioremap(0xffffffc0, 16);
 226         if (!romsig)
 227                 return 0;
 228
 229         if (strncmp(romsig, "CL1   Q", 7))
 230                 goto unmap;
 231         if (strncmp(romsig+6, romsig+13, 3)) {
 232                 printk(KERN_INFO "OLPC BIOS signature looks invalid.  "
 233                                 "Assuming not OLPC\n");
 234                 goto unmap;
 235         }
 236
 237         printk(KERN_INFO "OLPC board with OpenFirmware %.16s\n", romsig);
 238         olpc_platform_info.flags |= OLPC_F_PRESENT;
 239
 240         /* get the platform revision */
 241         platform_detect();
 242
 243         /* assume B1 and above models always have a DCON */
 244         if (olpc_board_at_least(olpc_board(0xb1)))
 245                 olpc_platform_info.flags |= OLPC_F_DCON;
 246
 247         /* get the EC revision */
 248         olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
 249                         (unsigned char *) &olpc_platform_info.ecver, 1);
 250
 251 #ifdef CONFIG_PCI_OLPC
 252         /* If the VSA exists let it emulate PCI, if not emulate in kernel */
 253         if (!cs5535_has_vsa2())
 254                 x86_init.pci.arch_init = pci_olpc_init;
 255 #endif
 256
 257         printk(KERN_INFO "OLPC board revision %s%X (EC=%x)\n",
 258                         ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
 259                         olpc_platform_info.boardrev >> 4,
 260                         olpc_platform_info.ecver);
 261
 262 unmap:
 263         iounmap(romsig);
 264         return 0;
 265 }
 266
 267 postcore_initcall(olpc_init);