diff options
Diffstat (limited to 'kernel/drivers/uwb/whc-rc.c')
| -rw-r--r-- | kernel/drivers/uwb/whc-rc.c | 481 |
1 files changed, 481 insertions, 0 deletions
diff --git a/kernel/drivers/uwb/whc-rc.c b/kernel/drivers/uwb/whc-rc.c new file mode 100644 index 000000000..3ae3c7025 --- /dev/null +++ b/kernel/drivers/uwb/whc-rc.c @@ -0,0 +1,481 @@ +/* + * 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 <inaky.perez-gonzalez@intel.com> + * + * 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" + +/** + * Descriptor for an instance of the UWB Radio Control Driver that + * attaches to the URC interface of the WHCI PCI card. + * + * Unless there is a lock specific to the 'data members', all access + * is protected by uwb_rc->mutex. + */ +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; +}; + +/** + * Execute an UWB RC command on WHCI/RC + * + * @rc: Instance of a Radio Controller that is a whcrc + * @cmd: Buffer containing the RCCB and payload to execute + * @cmd_size: Size of the command buffer. + * + * We copy the command into whcrc->cmd_buf (as it is pretty and + * aligned`and physically contiguous) and then press the right keys in + * the controller's URCCMD register to get it to read it. We might + * have to wait for the cmd_sem to be open to us. + * + * NOTE: rc's mutex has to be locked + */ +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); +} + +/** + * Reset event reception mechanism and tell hw we are ready to get more + * + * We have read all the events in the event buffer, so we are ready to + * reset it to the beginning. + * + * This is only called during initialization or after an event buffer + * has been retired. This means we can be sure that event processing + * is disabled and it's safe to update the URCEVTADDR register. + * + * There's no need to wait for the event processing to start as the + * URC will not clear URCCMD_ACTIVE until (internal) event buffer + * space is available. + */ +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); +} + +/** + * Catch interrupts? + * + * We ack inmediately (and expect the hw to do the right thing and + * raise another IRQ if things have changed :) + */ +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; +} + + +/** + * Initialize a UMC RC interface: map regions, get (shared) IRQ + */ +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; +} + + +/** + * Release RC's UMC resources + */ +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); +} + + +/** + * whcrc_start_rc - start a WHCI radio controller + * @whcrc: the radio controller to start + * + * Reset the UMC device, start the radio controller, enable events and + * finally enable interrupts. + */ +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; +} + + +/** + * whcrc_stop_rc - stop a WHCI radio controller + * @whcrc: the radio controller to stop + * + * Disable interrupts and cancel any pending event processing work + * before clearing the Run/Stop bit. + */ +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); +} + +/** + * Initialize the radio controller. + * + * NOTE: we setup whcrc->uwb_rc before calling uwb_rc_add(); in the + * IRQ handler we use that to determine if the hw is ready to + * handle events. Looks like a race condition, but it really is + * not. + */ +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; +} + +/** + * Clean up the radio control resources + * + * When we up the command semaphore, everybody possibly held trying to + * execute a command should be granted entry and then they'll see the + * host is quiescing and up it (so it will chain to the next waiter). + * This should not happen (in any case), as we can only remove when + * there are no handles open... + */ +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 <inaky.perez-gonzalez@intel.com>"); +MODULE_DESCRIPTION("Wireless Host Controller Radio Control Driver"); +MODULE_LICENSE("GPL"); |