whc-rc.c

Go to the documentation of this file.

/*
 * Wireless Host Controller: Radio Control Interface (WHCI v0.95[2.3])
 * Radio Control command/event transport to the UWB stack
 *
 * Copyright (C) 2005-2006 Intel Corporation
 * Inaky Perez-Gonzalez <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 *
 * Initialize and hook up the Radio Control interface.
 *
 * For each device probed, creates an 'struct whcrc' which contains
 * just the representation of the UWB Radio Controller, and the logic
 * for reading notifications and passing them to the UWB Core.
 *
 * So we initialize all of those, register the UWB Radio Controller
 * and setup the notification/event handle to pipe the notifications
 * to the UWB management Daemon.
 *
 * Once uwb_rc_add() is called, the UWB stack takes control, resets
 * the radio and readies the device to take commands the UWB
 * API/user-space.
 *
 * Note this driver is just a transport driver; the commands are
 * formed at the UWB stack and given to this driver who will deliver
 * them to the hw and transfer the replies/notifications back to the
 * UWB stack through the UWB daemon (UWBD).
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/sched.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/uwb.h>
#include <linux/uwb/whci.h>
#include <linux/uwb/umc.h>

#include "uwb-internal.h"

struct whcrc {
    struct umc_dev *umc_dev;
    struct uwb_rc *uwb_rc;      /* UWB host controller */

    unsigned long area;
    void __iomem *rc_base;
    size_t rc_len;
    spinlock_t irq_lock;

    void *evt_buf, *cmd_buf;
    dma_addr_t evt_dma_buf, cmd_dma_buf;
    wait_queue_head_t cmd_wq;
    struct work_struct event_work;
};

static int whcrc_cmd(struct uwb_rc *uwb_rc,
          const struct uwb_rccb *cmd, size_t cmd_size)
{
    int result = 0;
    struct whcrc *whcrc = uwb_rc->priv;
    struct device *dev = &whcrc->umc_dev->dev;
    u32 urccmd;

    if (cmd_size >= 4096)
        return -EINVAL;

    /*
     * If the URC is halted, then the hardware has reset itself.
     * Attempt to recover by restarting the device and then return
     * an error as it's likely that the current command isn't
     * valid for a newly started RC.
     */
    if (le_readl(whcrc->rc_base + URCSTS) & URCSTS_HALTED) {
        dev_err(dev, "requesting reset of halted radio controller\n");
        uwb_rc_reset_all(uwb_rc);
        return -EIO;
    }

    result = wait_event_timeout(whcrc->cmd_wq,
        !(le_readl(whcrc->rc_base + URCCMD) & URCCMD_ACTIVE), HZ/2);
    if (result == 0) {
        dev_err(dev, "device is not ready to execute commands\n");
        return -ETIMEDOUT;
    }

    memmove(whcrc->cmd_buf, cmd, cmd_size);
    le_writeq(whcrc->cmd_dma_buf, whcrc->rc_base + URCCMDADDR);

    spin_lock(&whcrc->irq_lock);
    urccmd = le_readl(whcrc->rc_base + URCCMD);
    urccmd &= ~(URCCMD_EARV | URCCMD_SIZE_MASK);
    le_writel(urccmd | URCCMD_ACTIVE | URCCMD_IWR | cmd_size,
          whcrc->rc_base + URCCMD);
    spin_unlock(&whcrc->irq_lock);

    return 0;
}

static int whcrc_reset(struct uwb_rc *rc)
{
    struct whcrc *whcrc = rc->priv;

    return umc_controller_reset(whcrc->umc_dev);
}

static
void whcrc_enable_events(struct whcrc *whcrc)
{
    u32 urccmd;

    le_writeq(whcrc->evt_dma_buf, whcrc->rc_base + URCEVTADDR);

    spin_lock(&whcrc->irq_lock);
    urccmd = le_readl(whcrc->rc_base + URCCMD) & ~URCCMD_ACTIVE;
    le_writel(urccmd | URCCMD_EARV, whcrc->rc_base + URCCMD);
    spin_unlock(&whcrc->irq_lock);
}

static void whcrc_event_work(struct work_struct *work)
{
    struct whcrc *whcrc = container_of(work, struct whcrc, event_work);
    size_t size;
    u64 urcevtaddr;

    urcevtaddr = le_readq(whcrc->rc_base + URCEVTADDR);
    size = urcevtaddr & URCEVTADDR_OFFSET_MASK;

    uwb_rc_neh_grok(whcrc->uwb_rc, whcrc->evt_buf, size);
    whcrc_enable_events(whcrc);
}

static
irqreturn_t whcrc_irq_cb(int irq, void *_whcrc)
{
    struct whcrc *whcrc = _whcrc;
    struct device *dev = &whcrc->umc_dev->dev;
    u32 urcsts;

    urcsts = le_readl(whcrc->rc_base + URCSTS);
    if (!(urcsts & URCSTS_INT_MASK))
        return IRQ_NONE;
    le_writel(urcsts & URCSTS_INT_MASK, whcrc->rc_base + URCSTS);

    if (urcsts & URCSTS_HSE) {
        dev_err(dev, "host system error -- hardware halted\n");
        /* FIXME: do something sensible here */
        goto out;
    }
    if (urcsts & URCSTS_ER)
        schedule_work(&whcrc->event_work);
    if (urcsts & URCSTS_RCI)
        wake_up_all(&whcrc->cmd_wq);
out:
    return IRQ_HANDLED;
}


static
int whcrc_setup_rc_umc(struct whcrc *whcrc)
{
    int result = 0;
    struct device *dev = &whcrc->umc_dev->dev;
    struct umc_dev *umc_dev = whcrc->umc_dev;

    whcrc->area = umc_dev->resource.start;
    whcrc->rc_len = resource_size(&umc_dev->resource);
    result = -EBUSY;
    if (request_mem_region(whcrc->area, whcrc->rc_len, KBUILD_MODNAME) == NULL) {
        dev_err(dev, "can't request URC region (%zu bytes @ 0x%lx): %d\n",
            whcrc->rc_len, whcrc->area, result);
        goto error_request_region;
    }

    whcrc->rc_base = ioremap_nocache(whcrc->area, whcrc->rc_len);
    if (whcrc->rc_base == NULL) {
        dev_err(dev, "can't ioremap registers (%zu bytes @ 0x%lx): %d\n",
            whcrc->rc_len, whcrc->area, result);
        goto error_ioremap_nocache;
    }

    result = request_irq(umc_dev->irq, whcrc_irq_cb, IRQF_SHARED,
                 KBUILD_MODNAME, whcrc);
    if (result < 0) {
        dev_err(dev, "can't allocate IRQ %d: %d\n",
            umc_dev->irq, result);
        goto error_request_irq;
    }

    result = -ENOMEM;
    whcrc->cmd_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
                        &whcrc->cmd_dma_buf, GFP_KERNEL);
    if (whcrc->cmd_buf == NULL) {
        dev_err(dev, "Can't allocate cmd transfer buffer\n");
        goto error_cmd_buffer;
    }

    whcrc->evt_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
                        &whcrc->evt_dma_buf, GFP_KERNEL);
    if (whcrc->evt_buf == NULL) {
        dev_err(dev, "Can't allocate evt transfer buffer\n");
        goto error_evt_buffer;
    }
    return 0;

error_evt_buffer:
    dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
              whcrc->cmd_dma_buf);
error_cmd_buffer:
    free_irq(umc_dev->irq, whcrc);
error_request_irq:
    iounmap(whcrc->rc_base);
error_ioremap_nocache:
    release_mem_region(whcrc->area, whcrc->rc_len);
error_request_region:
    return result;
}


static
void whcrc_release_rc_umc(struct whcrc *whcrc)
{
    struct umc_dev *umc_dev = whcrc->umc_dev;

    dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->evt_buf,
              whcrc->evt_dma_buf);
    dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
              whcrc->cmd_dma_buf);
    free_irq(umc_dev->irq, whcrc);
    iounmap(whcrc->rc_base);
    release_mem_region(whcrc->area, whcrc->rc_len);
}


static int whcrc_start_rc(struct uwb_rc *rc)
{
    struct whcrc *whcrc = rc->priv;
    struct device *dev = &whcrc->umc_dev->dev;

    /* Reset the thing */
    le_writel(URCCMD_RESET, whcrc->rc_base + URCCMD);
    if (whci_wait_for(dev, whcrc->rc_base + URCCMD, URCCMD_RESET, 0,
              5000, "hardware reset") < 0)
        return -EBUSY;

    /* Set the event buffer, start the controller (enable IRQs later) */
    le_writel(0, whcrc->rc_base + URCINTR);
    le_writel(URCCMD_RS, whcrc->rc_base + URCCMD);
    if (whci_wait_for(dev, whcrc->rc_base + URCSTS, URCSTS_HALTED, 0,
              5000, "radio controller start") < 0)
        return -ETIMEDOUT;
    whcrc_enable_events(whcrc);
    le_writel(URCINTR_EN_ALL, whcrc->rc_base + URCINTR);
    return 0;
}


static
void whcrc_stop_rc(struct uwb_rc *rc)
{
    struct whcrc *whcrc = rc->priv;
    struct umc_dev *umc_dev = whcrc->umc_dev;

    le_writel(0, whcrc->rc_base + URCINTR);
    cancel_work_sync(&whcrc->event_work);

    le_writel(0, whcrc->rc_base + URCCMD);
    whci_wait_for(&umc_dev->dev, whcrc->rc_base + URCSTS,
              URCSTS_HALTED, URCSTS_HALTED, 100, "radio controller stop");
}

static void whcrc_init(struct whcrc *whcrc)
{
    spin_lock_init(&whcrc->irq_lock);
    init_waitqueue_head(&whcrc->cmd_wq);
    INIT_WORK(&whcrc->event_work, whcrc_event_work);
}

static
int whcrc_probe(struct umc_dev *umc_dev)
{
    int result;
    struct uwb_rc *uwb_rc;
    struct whcrc *whcrc;
    struct device *dev = &umc_dev->dev;

    result = -ENOMEM;
    uwb_rc = uwb_rc_alloc();
    if (uwb_rc == NULL) {
        dev_err(dev, "unable to allocate RC instance\n");
        goto error_rc_alloc;
    }
    whcrc = kzalloc(sizeof(*whcrc), GFP_KERNEL);
    if (whcrc == NULL) {
        dev_err(dev, "unable to allocate WHC-RC instance\n");
        goto error_alloc;
    }
    whcrc_init(whcrc);
    whcrc->umc_dev = umc_dev;

    result = whcrc_setup_rc_umc(whcrc);
    if (result < 0) {
        dev_err(dev, "Can't setup RC UMC interface: %d\n", result);
        goto error_setup_rc_umc;
    }
    whcrc->uwb_rc = uwb_rc;

    uwb_rc->owner = THIS_MODULE;
    uwb_rc->cmd   = whcrc_cmd;
    uwb_rc->reset = whcrc_reset;
    uwb_rc->start = whcrc_start_rc;
    uwb_rc->stop  = whcrc_stop_rc;

    result = uwb_rc_add(uwb_rc, dev, whcrc);
    if (result < 0)
        goto error_rc_add;
    umc_set_drvdata(umc_dev, whcrc);
    return 0;

error_rc_add:
    whcrc_release_rc_umc(whcrc);
error_setup_rc_umc:
    kfree(whcrc);
error_alloc:
    uwb_rc_put(uwb_rc);
error_rc_alloc:
    return result;
}

static void whcrc_remove(struct umc_dev *umc_dev)
{
    struct whcrc *whcrc = umc_get_drvdata(umc_dev);
    struct uwb_rc *uwb_rc = whcrc->uwb_rc;

    umc_set_drvdata(umc_dev, NULL);
    uwb_rc_rm(uwb_rc);
    whcrc_release_rc_umc(whcrc);
    kfree(whcrc);
    uwb_rc_put(uwb_rc);
}

static int whcrc_pre_reset(struct umc_dev *umc)
{
    struct whcrc *whcrc = umc_get_drvdata(umc);
    struct uwb_rc *uwb_rc = whcrc->uwb_rc;

    uwb_rc_pre_reset(uwb_rc);
    return 0;
}

static int whcrc_post_reset(struct umc_dev *umc)
{
    struct whcrc *whcrc = umc_get_drvdata(umc);
    struct uwb_rc *uwb_rc = whcrc->uwb_rc;

    return uwb_rc_post_reset(uwb_rc);
}

/* PCI device ID's that we handle [so it gets loaded] */
static struct pci_device_id __used whcrc_id_table[] = {
    { PCI_DEVICE_CLASS(PCI_CLASS_WIRELESS_WHCI, ~0) },
    { /* empty last entry */ }
};
MODULE_DEVICE_TABLE(pci, whcrc_id_table);

static struct umc_driver whcrc_driver = {
    .name       = "whc-rc",
    .cap_id     = UMC_CAP_ID_WHCI_RC,
    .probe      = whcrc_probe,
    .remove     = whcrc_remove,
    .pre_reset  = whcrc_pre_reset,
    .post_reset = whcrc_post_reset,
};

static int __init whcrc_driver_init(void)
{
    return umc_driver_register(&whcrc_driver);
}
module_init(whcrc_driver_init);

static void __exit whcrc_driver_exit(void)
{
    umc_driver_unregister(&whcrc_driver);
}
module_exit(whcrc_driver_exit);

MODULE_AUTHOR("Inaky Perez-Gonzalez <[email protected]>");
MODULE_DESCRIPTION("Wireless Host Controller Radio Control Driver");
MODULE_LICENSE("GPL");