olpc.c

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/*
 * Support for the OLPC DCON and OLPC EC access
 *
 * Copyright © 2006  Advanced Micro Devices, Inc.
 * Copyright © 2007-2008  Andres Salomon <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/string.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/syscore_ops.h>
#include <linux/mutex.h>
#include <linux/olpc-ec.h>

#include <asm/geode.h>
#include <asm/setup.h>
#include <asm/olpc.h>
#include <asm/olpc_ofw.h>

struct olpc_platform_t olpc_platform_info;
EXPORT_SYMBOL_GPL(olpc_platform_info);

/* EC event mask to be applied during suspend (defining wakeup sources). */
static u16 ec_wakeup_mask;

/* what the timeout *should* be (in ms) */
#define EC_BASE_TIMEOUT 20

/* the timeout that bugs in the EC might force us to actually use */
static int ec_timeout = EC_BASE_TIMEOUT;

static int __init olpc_ec_timeout_set(char *str)
{
    if (get_option(&str, &ec_timeout) != 1) {
        ec_timeout = EC_BASE_TIMEOUT;
        printk(KERN_ERR "olpc-ec:  invalid argument to "
                "'olpc_ec_timeout=', ignoring!\n");
    }
    printk(KERN_DEBUG "olpc-ec:  using %d ms delay for EC commands.\n",
            ec_timeout);
    return 1;
}
__setup("olpc_ec_timeout=", olpc_ec_timeout_set);

/*
 * These {i,o}bf_status functions return whether the buffers are full or not.
 */

static inline unsigned int ibf_status(unsigned int port)
{
    return !!(inb(port) & 0x02);
}

static inline unsigned int obf_status(unsigned int port)
{
    return inb(port) & 0x01;
}

#define wait_on_ibf(p, d) __wait_on_ibf(__LINE__, (p), (d))
static int __wait_on_ibf(unsigned int line, unsigned int port, int desired)
{
    unsigned int timeo;
    int state = ibf_status(port);

    for (timeo = ec_timeout; state != desired && timeo; timeo--) {
        mdelay(1);
        state = ibf_status(port);
    }

    if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
            timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
        printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for IBF!\n",
                line, ec_timeout - timeo);
    }

    return !(state == desired);
}

#define wait_on_obf(p, d) __wait_on_obf(__LINE__, (p), (d))
static int __wait_on_obf(unsigned int line, unsigned int port, int desired)
{
    unsigned int timeo;
    int state = obf_status(port);

    for (timeo = ec_timeout; state != desired && timeo; timeo--) {
        mdelay(1);
        state = obf_status(port);
    }

    if ((state == desired) && (ec_timeout > EC_BASE_TIMEOUT) &&
            timeo < (ec_timeout - EC_BASE_TIMEOUT)) {
        printk(KERN_WARNING "olpc-ec:  %d: waited %u ms for OBF!\n",
                line, ec_timeout - timeo);
    }

    return !(state == desired);
}

/*
 * This allows the kernel to run Embedded Controller commands.  The EC is
 * documented at <http://wiki.laptop.org/go/Embedded_controller>, and the
 * available EC commands are here:
 * <http://wiki.laptop.org/go/Ec_specification>.  Unfortunately, while
 * OpenFirmware's source is available, the EC's is not.
 */
static int olpc_xo1_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf,
        size_t outlen, void *arg)
{
    int ret = -EIO;
    int i;
    int restarts = 0;

    /* Clear OBF */
    for (i = 0; i < 10 && (obf_status(0x6c) == 1); i++)
        inb(0x68);
    if (i == 10) {
        printk(KERN_ERR "olpc-ec:  timeout while attempting to "
                "clear OBF flag!\n");
        goto err;
    }

    if (wait_on_ibf(0x6c, 0)) {
        printk(KERN_ERR "olpc-ec:  timeout waiting for EC to "
                "quiesce!\n");
        goto err;
    }

restart:
    /*
     * Note that if we time out during any IBF checks, that's a failure;
     * we have to return.  There's no way for the kernel to clear that.
     *
     * If we time out during an OBF check, we can restart the command;
     * reissuing it will clear the OBF flag, and we should be alright.
     * The OBF flag will sometimes misbehave due to what we believe
     * is a hardware quirk..
     */
    pr_devel("olpc-ec:  running cmd 0x%x\n", cmd);
    outb(cmd, 0x6c);

    if (wait_on_ibf(0x6c, 0)) {
        printk(KERN_ERR "olpc-ec:  timeout waiting for EC to read "
                "command!\n");
        goto err;
    }

    if (inbuf && inlen) {
        /* write data to EC */
        for (i = 0; i < inlen; i++) {
            pr_devel("olpc-ec:  sending cmd arg 0x%x\n", inbuf[i]);
            outb(inbuf[i], 0x68);
            if (wait_on_ibf(0x6c, 0)) {
                printk(KERN_ERR "olpc-ec:  timeout waiting for"
                        " EC accept data!\n");
                goto err;
            }
        }
    }
    if (outbuf && outlen) {
        /* read data from EC */
        for (i = 0; i < outlen; i++) {
            if (wait_on_obf(0x6c, 1)) {
                printk(KERN_ERR "olpc-ec:  timeout waiting for"
                        " EC to provide data!\n");
                if (restarts++ < 10)
                    goto restart;
                goto err;
            }
            outbuf[i] = inb(0x68);
            pr_devel("olpc-ec:  received 0x%x\n", outbuf[i]);
        }
    }

    ret = 0;
err:
    return ret;
}

void olpc_ec_wakeup_set(u16 value)
{
    ec_wakeup_mask |= value;
}
EXPORT_SYMBOL_GPL(olpc_ec_wakeup_set);

void olpc_ec_wakeup_clear(u16 value)
{
    ec_wakeup_mask &= ~value;
}
EXPORT_SYMBOL_GPL(olpc_ec_wakeup_clear);

/*
 * Returns true if the compile and runtime configurations allow for EC events
 * to wake the system.
 */
bool olpc_ec_wakeup_available(void)
{
    if (!machine_is_olpc())
        return false;

    /*
     * XO-1 EC wakeups are available when olpc-xo1-sci driver is
     * compiled in
     */
#ifdef CONFIG_OLPC_XO1_SCI
    if (olpc_platform_info.boardrev < olpc_board_pre(0xd0)) /* XO-1 */
        return true;
#endif

    /*
     * XO-1.5 EC wakeups are available when olpc-xo15-sci driver is
     * compiled in
     */
#ifdef CONFIG_OLPC_XO15_SCI
    if (olpc_platform_info.boardrev >= olpc_board_pre(0xd0)) /* XO-1.5 */
        return true;
#endif

    return false;
}
EXPORT_SYMBOL_GPL(olpc_ec_wakeup_available);

int olpc_ec_mask_write(u16 bits)
{
    if (olpc_platform_info.flags & OLPC_F_EC_WIDE_SCI) {
        __be16 ec_word = cpu_to_be16(bits);
        return olpc_ec_cmd(EC_WRITE_EXT_SCI_MASK, (void *) &ec_word, 2,
                   NULL, 0);
    } else {
        unsigned char ec_byte = bits & 0xff;
        return olpc_ec_cmd(EC_WRITE_SCI_MASK, &ec_byte, 1, NULL, 0);
    }
}
EXPORT_SYMBOL_GPL(olpc_ec_mask_write);

int olpc_ec_sci_query(u16 *sci_value)
{
    int ret;

    if (olpc_platform_info.flags & OLPC_F_EC_WIDE_SCI) {
        __be16 ec_word;
        ret = olpc_ec_cmd(EC_EXT_SCI_QUERY,
            NULL, 0, (void *) &ec_word, 2);
        if (ret == 0)
            *sci_value = be16_to_cpu(ec_word);
    } else {
        unsigned char ec_byte;
        ret = olpc_ec_cmd(EC_SCI_QUERY, NULL, 0, &ec_byte, 1);
        if (ret == 0)
            *sci_value = ec_byte;
    }

    return ret;
}
EXPORT_SYMBOL_GPL(olpc_ec_sci_query);

static bool __init check_ofw_architecture(struct device_node *root)
{
    const char *olpc_arch;
    int propsize;

    olpc_arch = of_get_property(root, "architecture", &propsize);
    return propsize == 5 && strncmp("OLPC", olpc_arch, 5) == 0;
}

static u32 __init get_board_revision(struct device_node *root)
{
    int propsize;
    const __be32 *rev;

    rev = of_get_property(root, "board-revision-int", &propsize);
    if (propsize != 4)
        return 0;

    return be32_to_cpu(*rev);
}

static bool __init platform_detect(void)
{
    struct device_node *root = of_find_node_by_path("/");
    bool success;

    if (!root)
        return false;

    success = check_ofw_architecture(root);
    if (success) {
        olpc_platform_info.boardrev = get_board_revision(root);
        olpc_platform_info.flags |= OLPC_F_PRESENT;
    }

    of_node_put(root);
    return success;
}

static int __init add_xo1_platform_devices(void)
{
    struct platform_device *pdev;

    pdev = platform_device_register_simple("xo1-rfkill", -1, NULL, 0);
    if (IS_ERR(pdev))
        return PTR_ERR(pdev);

    pdev = platform_device_register_simple("olpc-xo1", -1, NULL, 0);
    if (IS_ERR(pdev))
        return PTR_ERR(pdev);

    return 0;
}

static int olpc_xo1_ec_probe(struct platform_device *pdev)
{
    /* get the EC revision */
    olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0,
            (unsigned char *) &olpc_platform_info.ecver, 1);

    /* EC version 0x5f adds support for wide SCI mask */
    if (olpc_platform_info.ecver >= 0x5f)
        olpc_platform_info.flags |= OLPC_F_EC_WIDE_SCI;

    pr_info("OLPC board revision %s%X (EC=%x)\n",
            ((olpc_platform_info.boardrev & 0xf) < 8) ? "pre" : "",
            olpc_platform_info.boardrev >> 4,
            olpc_platform_info.ecver);

    return 0;
}
static int olpc_xo1_ec_suspend(struct platform_device *pdev)
{
    olpc_ec_mask_write(ec_wakeup_mask);

    /*
     * Squelch SCIs while suspended.  This is a fix for
     * <http://dev.laptop.org/ticket/1835>.
     */
    return olpc_ec_cmd(EC_SET_SCI_INHIBIT, NULL, 0, NULL, 0);
}

static int olpc_xo1_ec_resume(struct platform_device *pdev)
{
    /* Tell the EC to stop inhibiting SCIs */
    olpc_ec_cmd(EC_SET_SCI_INHIBIT_RELEASE, NULL, 0, NULL, 0);

    /*
     * Tell the wireless module to restart USB communication.
     * Must be done twice.
     */
    olpc_ec_cmd(EC_WAKE_UP_WLAN, NULL, 0, NULL, 0);
    olpc_ec_cmd(EC_WAKE_UP_WLAN, NULL, 0, NULL, 0);

    return 0;
}

static struct olpc_ec_driver ec_xo1_driver = {
    .probe = olpc_xo1_ec_probe,
    .suspend = olpc_xo1_ec_suspend,
    .resume = olpc_xo1_ec_resume,
    .ec_cmd = olpc_xo1_ec_cmd,
};

static struct olpc_ec_driver ec_xo1_5_driver = {
    .probe = olpc_xo1_ec_probe,
    .ec_cmd = olpc_xo1_ec_cmd,
};

static int __init olpc_init(void)
{
    int r = 0;

    if (!olpc_ofw_present() || !platform_detect())
        return 0;

    /* register the XO-1 and 1.5-specific EC handler */
    if (olpc_platform_info.boardrev < olpc_board_pre(0xd0)) /* XO-1 */
        olpc_ec_driver_register(&ec_xo1_driver, NULL);
    else
        olpc_ec_driver_register(&ec_xo1_5_driver, NULL);
    platform_device_register_simple("olpc-ec", -1, NULL, 0);

    /* assume B1 and above models always have a DCON */
    if (olpc_board_at_least(olpc_board(0xb1)))
        olpc_platform_info.flags |= OLPC_F_DCON;

#ifdef CONFIG_PCI_OLPC
    /* If the VSA exists let it emulate PCI, if not emulate in kernel.
     * XO-1 only. */
    if (olpc_platform_info.boardrev < olpc_board_pre(0xd0) &&
            !cs5535_has_vsa2())
        x86_init.pci.arch_init = pci_olpc_init;
#endif

    if (olpc_platform_info.boardrev < olpc_board_pre(0xd0)) { /* XO-1 */
        r = add_xo1_platform_devices();
        if (r)
            return r;
    }

    return 0;
}

postcore_initcall(olpc_init);