LXR linux/arch/x86/platform/olpc/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
  27struct olpc_platform_t olpc_platform_info;
  28EXPORT_SYMBOL_GPL(olpc_platform_info);
  29
  30static 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 */
  36static int ec_timeout = EC_BASE_TIMEOUT;
  37
  38static 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
  55static inline unsigned int ibf_status(unsigned int port)
  56{
  57        return !!(inb(port) & 0x02);
  58}
  59
  60static 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))
  66static 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))
  86static 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 */
 112int 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
 137restart:
 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;
 184err:
 185        spin_unlock_irqrestore(&ec_lock, flags);
 186        return ret;
 187}
 188EXPORT_SYMBOL_GPL(olpc_ec_cmd);
 189
 190static 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
 204static 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
 218static 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
 227static 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
 242static 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
 281postcore_initcall(olpc_init);
 282