uwb: add whc-rc radio control driver

Add the driver for WHCI radio controllers.

Signed-off-by: David Vrabel <david.vrabel@csr.com>

1 files changed, 528 insertions, 0 deletions

diff --git a/drivers/uwb/whc-rc.c b/drivers/uwb/whc-rc.c
new file mode 100644
index 0000000..5a93abe
--- /dev/null
+++ b/drivers/uwb/whc-rc.c
@@ -0,0 +1,528 @@
+/*
+ * 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/version.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/workqueue.h>
+#include <linux/uwb.h>
+#include <linux/uwb/whci.h>
+#include <linux/uwb/umc.h>
+#include "uwb-internal.h"
+
+#define D_LOCAL 0
+#include <linux/uwb/debug.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;
+
+	d_fnstart(3, dev, "(%p, %p, %zu)\n", uwb_rc, cmd, cmd_size);
+	might_sleep();
+
+	if (cmd_size >= 4096) {
+		result = -E2BIG;
+		goto error;
+	}
+
+	/*
+	 * 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);
+		result = -EIO;
+		goto error;
+	}
+
+	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");
+		result = -ETIMEDOUT;
+		goto error;
+	}
+
+	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);
+
+error:
+	d_fnend(3, dev, "(%p, %p, %zu) = %d\n",
+		uwb_rc, cmd, cmd_size, result);
+	return result;
+}
+
+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)
+{
+	struct device *dev = &whcrc->umc_dev->dev;
+	u32 urccmd;
+
+	d_fnstart(4, dev, "(whcrc %p)\n", whcrc);
+
+	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);
+
+	d_fnend(4, dev, "(whcrc %p) = void\n", whcrc);
+}
+
+static void whcrc_event_work(struct work_struct *work)
+{
+	struct whcrc *whcrc = container_of(work, struct whcrc, event_work);
+	struct device *dev = &whcrc->umc_dev->dev;
+	size_t size;
+	u64 urcevtaddr;
+
+	urcevtaddr = le_readq(whcrc->rc_base + URCEVTADDR);
+	size = urcevtaddr & URCEVTADDR_OFFSET_MASK;
+
+	d_printf(3, dev, "received %zu octet event\n", size);
+	d_dump(4, dev, whcrc->evt_buf, size > 32 ? 32 : size);
+
+	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;
+
+	d_fnstart(4, dev, "irq %d _whcrc %p)\n", irq, _whcrc);
+	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);
+
+	d_printf(4, dev, "acked 0x%08x, urcsts 0x%08x\n",
+		 le_readl(whcrc->rc_base + URCSTS), urcsts);
+
+	if (whcrc->uwb_rc == NULL) {
+		if (printk_ratelimit())
+			dev_dbg(dev, "Received interrupt when not yet "
+				"ready!\n");
+		goto out;
+	}
+
+	if (urcsts & URCSTS_HSE) {
+		dev_err(dev, "host system error -- hardware halted\n");
+		/* FIXME: do something sensible here */
+		goto out;
+	}
+	if (urcsts & URCSTS_ER) {
+		d_printf(3, dev, "ER: event ready\n");
+		schedule_work(&whcrc->event_work);
+	}
+	if (urcsts & URCSTS_RCI) {
+		d_printf(3, dev, "RCI: ready to execute another command\n");
+		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 = umc_dev->resource.end - umc_dev->resource.start + 1;
+	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;
+	}
+	d_printf(3, dev, "UWB RC Interface: %zu bytes at 0x%p, irq %u\n",
+		 whcrc->rc_len, whcrc->rc_base, umc_dev->irq);
+	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;
+	int result = 0;
+	struct device *dev = &whcrc->umc_dev->dev;
+	unsigned long start, duration;
+
+	/* Reset the thing */
+	le_writel(URCCMD_RESET, whcrc->rc_base + URCCMD);
+	if (d_test(3))
+		start = jiffies;
+	if (whci_wait_for(dev, whcrc->rc_base + URCCMD, URCCMD_RESET, 0,
+			  5000, "device to reset at init") < 0) {
+		result = -EBUSY;
+		goto error;
+	} else if (d_test(3)) {
+		duration = jiffies - start;
+		if (duration > msecs_to_jiffies(40))
+			dev_err(dev, "Device took %ums to "
+				     "reset. MAX expected: 40ms\n",
+				     jiffies_to_msecs(duration));
+	}
+
+	/* 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);
+	result = -ETIMEDOUT;
+	if (d_test(3))
+		start = jiffies;
+	if (whci_wait_for(dev, whcrc->rc_base + URCSTS, URCSTS_HALTED, 0,
+			  5000, "device to start") < 0)
+		goto error;
+	if (d_test(3)) {
+		duration = jiffies - start;
+		if (duration > msecs_to_jiffies(40))
+			dev_err(dev, "Device took %ums to start. "
+				     "MAX expected: 40ms\n",
+				     jiffies_to_msecs(duration));
+	}
+	whcrc_enable_events(whcrc);
+	result = 0;
+	le_writel(URCINTR_EN_ALL, whcrc->rc_base + URCINTR);
+error:
+	return result;
+}
+
+
+/**
+ * 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, 0, 40, "URCSTS.HALTED");
+}
+
+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;
+
+	d_fnstart(3, dev, "(umc_dev %p)\n", umc_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);
+	d_fnend(3, dev, "(umc_dev %p) = 0\n", umc_dev);
+	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:
+	d_fnend(3, dev, "(umc_dev %p) = %d\n", umc_dev, result);
+	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);
+	d_printf(1, &umc_dev->dev, "freed whcrc %p\n", whcrc);
+}
+
+/* PCI device ID's that we handle [so it gets loaded] */
+static struct pci_device_id 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,
+};
+
+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");