[PATCH 11/15] cw1200: v3: main processing loop

[Solomon Peachy <pizza@shaftnet.org>]

Signed-off-by: Solomon Peachy <pizza@shaftnet.org>
---
 drivers/staging/cw1200/bh.c | 700 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/staging/cw1200/bh.h |  28 ++
 2 files changed, 728 insertions(+)
 create mode 100644 drivers/staging/cw1200/bh.c
 create mode 100644 drivers/staging/cw1200/bh.h

diff --git a/drivers/staging/cw1200/bh.c b/drivers/staging/cw1200/bh.c
new file mode 100644
index 0000000..a59d1f4
--- /dev/null
+++ b/drivers/staging/cw1200/bh.c
@@ -0,0 +1,700 @@
+/*
+ * Device handling thread implementation for mac80211 ST-Ericsson CW1200 drivers
+ *
+ * Copyright (c) 2010, ST-Ericsson
+ * Author: Dmitry Tarnyagin <dmitry.tarnyagin@stericsson.com>
+ *
+ * Based on:
+ * ST-Ericsson UMAC CW1200 driver, which is
+ * Copyright (c) 2010, ST-Ericsson
+ * Author: Ajitpal Singh <ajitpal.singh@stericsson.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.
+ */
+
+#include <linux/module.h>
+#include <net/mac80211.h>
+#include <linux/kthread.h>
+#include <linux/timer.h>
+
+#include "cw1200.h"
+#include "bh.h"
+#include "hwio.h"
+#include "wsm.h"
+#include "sbus.h"
+#include "debug.h"
+#include "fwio.h"
+
+static int cw1200_bh(void *arg);
+
+/* TODO: Verify these numbers with WSM specification. */
+#define DOWNLOAD_BLOCK_SIZE_WR	(0x1000 - 4)
+/* an SPI message cannot be bigger than (2"12-1)*2 bytes
+ * "*2" to cvt to bytes */
+#define MAX_SZ_RD_WR_BUFFERS	(DOWNLOAD_BLOCK_SIZE_WR*2)
+#define PIGGYBACK_CTRL_REG	(2)
+#define EFFECTIVE_BUF_SIZE	(MAX_SZ_RD_WR_BUFFERS - PIGGYBACK_CTRL_REG)
+
+/* Suspend state privates */
+enum cw1200_bh_pm_state {
+	CW1200_BH_RESUMED = 0,
+	CW1200_BH_SUSPEND,
+	CW1200_BH_SUSPENDED,
+	CW1200_BH_RESUME,
+};
+
+typedef int (*cw1200_wsm_handler)(struct cw1200_common *priv,
+	u8 *data, size_t size);
+
+#ifdef CONFIG_CW1200_POLL_IRQ
+static void cw1200_irqpoll_timer_fn(unsigned long arg)
+{
+	struct cw1200_common *priv = (struct cw1200_common *) arg;
+
+	if (atomic_add_return(1, &priv->bh_rx) == 1)
+		wake_up(&priv->bh_wq);
+}
+#endif
+
+#ifndef CW1200_USE_COMPAT_KTHREAD
+static void cw1200_bh_work(struct work_struct *work)
+{
+	struct cw1200_common *priv =
+	container_of(work, struct cw1200_common, bh_work);
+	pr_debug("[BH] %s enter\n", __func__);
+	cw1200_bh(priv);
+	pr_debug("[BH] %s exit\n", __func__);
+}
+#endif
+
+int cw1200_register_bh(struct cw1200_common *priv)
+{
+	int err = 0;
+#ifdef CW1200_USE_COMPAT_KTHREAD
+	struct sched_param param = { .sched_priority = 1 };
+	BUG_ON(priv->bh_thread);
+#else
+	/* Realtime workqueue */
+	priv->bh_workqueue = alloc_workqueue("cw1200_bh",
+				WQ_MEM_RECLAIM | WQ_HIGHPRI
+				| WQ_CPU_INTENSIVE, 1);
+
+	if (!priv->bh_workqueue)
+		return -ENOMEM;
+
+	INIT_WORK(&priv->bh_work, cw1200_bh_work);
+#endif
+
+	pr_debug("[BH] register.\n");
+
+	atomic_set(&priv->bh_rx, 0);
+	atomic_set(&priv->bh_tx, 0);
+	atomic_set(&priv->bh_term, 0);
+	atomic_set(&priv->bh_suspend, CW1200_BH_RESUMED);
+	priv->bh_error = 0;
+	priv->hw_bufs_used = 0;
+	priv->buf_id_tx = 0;
+	priv->buf_id_rx = 0;
+	init_waitqueue_head(&priv->bh_wq);
+	init_waitqueue_head(&priv->bh_evt_wq);
+
+#ifdef CW1200_USE_COMPAT_KTHREAD
+	priv->bh_thread = kthread_create(&cw1200_bh, priv, "cw1200_bh");
+	if (IS_ERR(priv->bh_thread)) {
+		err = PTR_ERR(priv->bh_thread);
+		priv->bh_thread = NULL;
+	} else {
+		WARN_ON(sched_setscheduler(priv->bh_thread,
+					   SCHED_FIFO, &param));
+#ifdef HAS_PUT_TASK_STRUCT
+		get_task_struct(priv->bh_thread);
+#endif
+		wake_up_process(priv->bh_thread);
+	}
+#else
+	err = !queue_work(priv->bh_workqueue, &priv->bh_work);
+	WARN_ON(err);
+#endif
+
+#ifdef CONFIG_CW1200_POLL_IRQ
+	init_timer(&priv->irqpoll_timer);
+	priv->irqpoll_timer.data = (unsigned long) priv;
+	priv->irqpoll_timer.function = cw1200_irqpoll_timer_fn;
+	mod_timer(&priv->irqpoll_timer, jiffies + HZ/100);
+#endif
+
+	return err;
+}
+
+void cw1200_unregister_bh(struct cw1200_common *priv)
+{
+#ifdef CW1200_USE_COMPAT_KTHREAD
+	struct task_struct *thread = priv->bh_thread;
+	if (WARN_ON(!thread))
+		return;
+#endif
+
+#ifdef CONFIG_CW1200_POLL_IRQ
+	del_timer_sync(&priv->irqpoll_timer);
+#endif
+	atomic_add(1, &priv->bh_term);
+	wake_up(&priv->bh_wq);
+
+#ifdef CW1200_USE_COMPAT_KTHREAD
+	kthread_stop(thread);
+#ifdef HAS_PUT_TASK_STRUCT
+	put_task_struct(thread);
+#endif
+	priv->bh_thread = NULL;
+#else
+	flush_workqueue(priv->bh_workqueue);
+
+	destroy_workqueue(priv->bh_workqueue);
+	priv->bh_workqueue = NULL;
+#endif
+
+	pr_debug("[BH] unregistered.\n");
+}
+
+void cw1200_irq_handler(struct cw1200_common *priv)
+{
+	pr_debug("[BH] irq.\n");
+	if (/* WARN_ON */(priv->bh_error))
+		return;
+
+#ifndef CONFIG_CW1200_POLL_IRQ
+	/* Disable Interrupts */
+	/* NOTE:  sbus_ops->lock already held */
+	if (priv->sbus_ops->irq_enable)
+		priv->sbus_ops->irq_enable(priv->sbus_priv, 0);
+#endif
+
+	if (atomic_add_return(1, &priv->bh_rx) == 1)
+		wake_up(&priv->bh_wq);
+}
+EXPORT_SYMBOL_GPL(cw1200_irq_handler);
+
+void cw1200_bh_wakeup(struct cw1200_common *priv)
+{
+	pr_debug("[BH] wakeup.\n");
+	if (priv->bh_error) {
+		pr_err("[BH] wakeup failed (BH error)\n");
+		return;
+	}
+
+	if (atomic_add_return(1, &priv->bh_tx) == 1)
+		wake_up(&priv->bh_wq);
+}
+
+int cw1200_bh_suspend(struct cw1200_common *priv)
+{
+	pr_debug("[BH] suspend.\n");
+	if (priv->bh_error) {
+		wiphy_warn(priv->hw->wiphy, "BH error -- can't suspend\n");
+		return -EINVAL;
+	}
+
+	atomic_set(&priv->bh_suspend, CW1200_BH_SUSPEND);
+	wake_up(&priv->bh_wq);
+	return wait_event_timeout(priv->bh_evt_wq, priv->bh_error ||
+		(CW1200_BH_SUSPENDED == atomic_read(&priv->bh_suspend)),
+		 1 * HZ) ? 0 : -ETIMEDOUT;
+}
+
+int cw1200_bh_resume(struct cw1200_common *priv)
+{
+	pr_debug("[BH] resume.\n");
+	if (priv->bh_error) {
+		wiphy_warn(priv->hw->wiphy, "BH error -- can't resume\n");
+		return -EINVAL;
+	}
+
+	atomic_set(&priv->bh_suspend, CW1200_BH_RESUME);
+	wake_up(&priv->bh_wq);
+	return wait_event_timeout(priv->bh_evt_wq, priv->bh_error ||
+		(CW1200_BH_RESUMED == atomic_read(&priv->bh_suspend)),
+		1 * HZ) ? 0 : -ETIMEDOUT;
+}
+
+static inline void wsm_alloc_tx_buffer(struct cw1200_common *priv)
+{
+	++priv->hw_bufs_used;
+}
+
+int wsm_release_tx_buffer(struct cw1200_common *priv, int count)
+{
+	int ret = 0;
+	int hw_bufs_used = priv->hw_bufs_used;
+
+	priv->hw_bufs_used -= count;
+	if (WARN_ON(priv->hw_bufs_used < 0))
+		ret = -1;
+	else if (hw_bufs_used >= priv->wsm_caps.numInpChBufs)
+		ret = 1;
+	if (!priv->hw_bufs_used)
+		wake_up(&priv->bh_evt_wq);
+	return ret;
+}
+
+static int cw1200_bh_read_ctrl_reg(struct cw1200_common *priv,
+					  u16 *ctrl_reg)
+{
+	int ret;
+
+	ret = cw1200_reg_read_16(priv,
+			ST90TDS_CONTROL_REG_ID, ctrl_reg);
+	if (ret) {
+		ret = cw1200_reg_read_16(priv,
+				ST90TDS_CONTROL_REG_ID, ctrl_reg);
+		if (ret)
+			pr_err("[BH] Failed to read control register.\n");
+	}
+
+	return ret;
+}
+
+static int cw1200_device_wakeup(struct cw1200_common *priv)
+{
+	u16 ctrl_reg;
+	int ret;
+
+	pr_debug("[BH] Device wakeup.\n");
+
+	/* First, set the dpll register */
+	ret = cw1200_reg_write_32(priv, ST90TDS_TSET_GEN_R_W_REG_ID, cw1200_dpll_from_clk(priv->hw_refclk));
+	if (WARN_ON(ret))
+		return ret;
+
+	/* To force the device to be always-on, the host sets WLAN_UP to 1 */
+	ret = cw1200_reg_write_16(priv, ST90TDS_CONTROL_REG_ID,
+			ST90TDS_CONT_WUP_BIT);
+	if (WARN_ON(ret))
+		return ret;
+
+	ret = cw1200_bh_read_ctrl_reg(priv, &ctrl_reg);
+	if (WARN_ON(ret))
+		return ret;
+
+	/* If the device returns WLAN_RDY as 1, the device is active and will
+	 * remain active. */
+	if (ctrl_reg & ST90TDS_CONT_RDY_BIT) {
+		pr_debug("[BH] Device awake.\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+/* Must be called from BH thraed. */
+void cw1200_enable_powersave(struct cw1200_common *priv,
+			     bool enable)
+{
+	pr_debug("[BH] Powerave is %s.\n",
+			enable ? "enabled" : "disabled");
+	priv->powersave_enabled = enable;
+}
+
+static int cw1200_bh_rx_helper(struct cw1200_common *priv,
+			       uint16_t *ctrl_reg,
+			       int *tx)
+{
+	size_t read_len = 0;
+	struct sk_buff *skb_rx = NULL;
+	struct wsm_hdr *wsm;
+	size_t wsm_len;
+	u16 wsm_id;
+	u8 wsm_seq;
+	int rx_resync = 1;
+
+	size_t alloc_len;
+	u8 *data;
+
+	read_len = (*ctrl_reg & ST90TDS_CONT_NEXT_LEN_MASK) * 2;
+	if (!read_len)
+		return 0; /* No more work */
+
+	if (WARN_ON((read_len < sizeof(struct wsm_hdr)) ||
+		    (read_len > EFFECTIVE_BUF_SIZE))) {
+		pr_debug("Invalid read len: %d (%04x)",
+		       read_len, *ctrl_reg);
+		goto err;
+	}
+
+	/* Add SIZE of PIGGYBACK reg (CONTROL Reg)
+	 * to the NEXT Message length + 2 Bytes for SKB */
+	read_len = read_len + 2;
+
+	alloc_len = priv->sbus_ops->align_size(
+		priv->sbus_priv, read_len);
+
+	/* Check if not exceeding CW1200 capabilities */
+	if (WARN_ON_ONCE(alloc_len > EFFECTIVE_BUF_SIZE)) {
+		pr_debug("Read aligned len: %d\n",
+		       alloc_len);
+	}
+
+	skb_rx = dev_alloc_skb(alloc_len);
+	if (WARN_ON(!skb_rx))
+		goto err;
+
+	skb_trim(skb_rx, 0);
+	skb_put(skb_rx, read_len);
+	data = skb_rx->data;
+	if (WARN_ON(!data))
+		goto err;
+
+	if (WARN_ON(cw1200_data_read(priv, data, alloc_len))) {
+		pr_err("rx blew up, len %d\n", alloc_len);
+		goto err;
+	}
+
+	/* Piggyback */
+	*ctrl_reg = __le16_to_cpu(
+		((__le16 *)data)[alloc_len / 2 - 1]);
+
+	wsm = (struct wsm_hdr *)data;
+	wsm_len = __le16_to_cpu(wsm->len);
+	if (WARN_ON(wsm_len > read_len))
+		goto err;
+
+	if (unlikely(priv->wsm_enable_wsm_dumps))
+		print_hex_dump_bytes("<-- ",
+				     DUMP_PREFIX_NONE,
+				     data, wsm_len);
+
+	wsm_id  = __le16_to_cpu(wsm->id) & 0xFFF;
+	wsm_seq = (__le16_to_cpu(wsm->id) >> 13) & 7;
+
+	skb_trim(skb_rx, wsm_len);
+
+	if (unlikely(wsm_id == 0x0800)) {
+		wsm_handle_exception(priv,
+				     &data[sizeof(*wsm)],
+				     wsm_len - sizeof(*wsm));
+		goto err;
+	} else if (unlikely(!rx_resync)) {
+		if (WARN_ON(wsm_seq != priv->wsm_rx_seq))
+			goto err;
+	}
+	priv->wsm_rx_seq = (wsm_seq + 1) & 7;
+	rx_resync = 0;
+
+	if (wsm_id & 0x0400) {
+		int rc = wsm_release_tx_buffer(priv, 1);
+		if (WARN_ON(rc < 0))
+			return rc;
+		else if (rc > 0)
+			*tx = 1;
+	}
+
+	/* cw1200_wsm_rx takes care on SKB livetime */
+	if (WARN_ON(wsm_handle_rx(priv, wsm_id, wsm, &skb_rx)))
+		goto err;
+
+	if (skb_rx) {
+		dev_kfree_skb(skb_rx);
+		skb_rx = NULL;
+	}
+
+	return 0;
+
+err:
+	if (skb_rx) {
+		dev_kfree_skb(skb_rx);
+		skb_rx = NULL;
+	}
+	return -1;
+}
+
+static int cw1200_bh_tx_helper(struct cw1200_common *priv,
+			       int *pending_tx,
+			       int *tx_burst)
+{
+	size_t tx_len;
+	u8 *data;
+	int ret;
+	struct wsm_hdr *wsm;
+
+	if (priv->device_can_sleep) {
+		ret = cw1200_device_wakeup(priv);
+		if (WARN_ON(ret < 0)) { /* Error in wakeup */
+			*pending_tx = 1;
+			return 0;
+		} else if (ret) { /* Woke up */
+			priv->device_can_sleep = false;
+		} else { /* Did not awake */
+			*pending_tx = 1;
+			return 0;
+		}
+	}
+
+	wsm_alloc_tx_buffer(priv);
+	ret = wsm_get_tx(priv, &data, &tx_len, tx_burst);
+	if (ret <= 0) {
+		wsm_release_tx_buffer(priv, 1);
+		if (WARN_ON(ret < 0))
+			return ret; /* Error */
+		return 0; /* No work */
+	}
+
+	wsm = (struct wsm_hdr *)data;
+	BUG_ON(tx_len < sizeof(*wsm));
+	BUG_ON(__le16_to_cpu(wsm->len) != tx_len);
+
+	atomic_add(1, &priv->bh_tx);
+
+	tx_len = priv->sbus_ops->align_size(
+		priv->sbus_priv, tx_len);
+
+	/* Check if not exceeding CW1200 capabilities */
+	if (WARN_ON_ONCE(tx_len > EFFECTIVE_BUF_SIZE))
+		pr_debug("Write aligned len: %d\n", tx_len);
+
+	wsm->id &= __cpu_to_le16(~WSM_TX_SEQ(WSM_TX_SEQ_MAX));
+	wsm->id |= __cpu_to_le16(WSM_TX_SEQ(priv->wsm_tx_seq));
+
+	if (WARN_ON(cw1200_data_write(priv, data, tx_len))) {
+		pr_err("tx blew up, len %d\n", tx_len);
+		wsm_release_tx_buffer(priv, 1);
+		return -1; /* Error */
+	}
+
+	if (unlikely(priv->wsm_enable_wsm_dumps))
+		print_hex_dump_bytes("--> ",
+				     DUMP_PREFIX_NONE,
+				     data,
+				     __le16_to_cpu(wsm->len));
+
+	wsm_txed(priv, data);
+	priv->wsm_tx_seq = (priv->wsm_tx_seq + 1) & WSM_TX_SEQ_MAX;
+
+	if (*tx_burst > 1) {
+		cw1200_debug_tx_burst(priv);
+		return 1; /* Work remains */
+	}
+
+	return 0;
+}
+
+static int cw1200_bh(void *arg)
+{
+	struct cw1200_common *priv = arg;
+	int rx, tx, term, suspend;
+	u16 ctrl_reg = 0;
+	int tx_allowed;
+	int pending_tx = 0;
+	int tx_burst;
+	long status;
+	u32 dummy;
+	int ret;
+
+	for (;;) {
+		if (!priv->hw_bufs_used &&
+		    priv->powersave_enabled &&
+		    !priv->device_can_sleep &&
+		    !atomic_read(&priv->recent_scan)) {
+			status = 1 * HZ;
+			pr_debug("[BH] Device wakedown. No data.\n");
+			WARN_ON(cw1200_reg_write_16(priv,
+						ST90TDS_CONTROL_REG_ID, 0));
+			priv->device_can_sleep = true;
+		} else if (priv->hw_bufs_used) {
+			/* Interrupt loss detection */
+			status = 1 * HZ;
+		} else {
+			status = MAX_SCHEDULE_TIMEOUT;
+		}
+
+		/* Dummy Read for SDIO retry mechanism*/
+		if ((priv->hw_type != -1) &&
+		    (atomic_read(&priv->bh_rx) == 0) &&
+		    (atomic_read(&priv->bh_tx) == 0))
+			cw1200_reg_read(priv, ST90TDS_CONFIG_REG_ID,
+					&dummy, sizeof(dummy));
+
+		pr_debug("[BH] waiting ...\n");
+		status = wait_event_interruptible_timeout(priv->bh_wq, ({
+				rx = atomic_xchg(&priv->bh_rx, 0);
+				tx = atomic_xchg(&priv->bh_tx, 0);
+				term = atomic_xchg(&priv->bh_term, 0);
+				suspend = pending_tx ?
+					0 : atomic_read(&priv->bh_suspend);
+				(rx || tx || term || suspend || priv->bh_error);
+			}), status);
+
+		pr_debug("[BH] - rx: %d, tx: %d, term: %d, suspend: %d, status: %ld\n",
+			 rx, tx, term, suspend, status);
+
+		/* Did an error occur? */
+		if ((status < 0 && status != -ERESTARTSYS) ||
+		    term || priv->bh_error) {
+			break;
+		}
+
+		if (priv->hw_bufs_used) { /* Outstanding tx in h/w */
+			unsigned long timestamp = jiffies;
+			long timeout;
+			int pending = 0;
+			int i;
+
+			if (!status && (!rx || !tx)) {
+				wiphy_warn(priv->hw->wiphy, "Missed interrupt? (%d outstanding)\n", priv->hw_bufs_used);
+				rx = 1;
+			}
+
+			/* Get a timestamp of "oldest" frame */
+			for (i = 0; i < 4; ++i)
+				pending += cw1200_queue_get_xmit_timestamp(
+						&priv->tx_queue[i],
+						&timestamp, priv->pending_frame_id);
+
+			/* Check if frame transmission is timed out.
+			 * Add an extra second with respect to possible
+			 * interrupt loss. */
+			timeout = timestamp +
+					WSM_CMD_LAST_CHANCE_TIMEOUT +
+					1 * HZ  -
+					jiffies;
+
+			/* And terminate BH tread if the frame is "stuck" */
+			if (pending && timeout < 0) {
+				wiphy_warn(priv->hw->wiphy,
+					   "Timeout waiting for TX confirm (%d/%d pending, %ld vs %lu).\n", priv->hw_bufs_used, pending, timestamp, jiffies);
+				break;
+			}
+		} else if (!status) {
+			if (!priv->device_can_sleep
+					&& !atomic_read(&priv->recent_scan)) {
+				pr_debug("[BH] Device wakedown. Timeout.\n");
+				WARN_ON(cw1200_reg_write_16(priv,
+						ST90TDS_CONTROL_REG_ID, 0));
+				priv->device_can_sleep = true;
+			}
+			goto done;
+		} else if (suspend) {
+			pr_debug("[BH] Device suspend.\n");
+			if (priv->powersave_enabled) {
+				pr_debug("[BH] Device wakedown. Suspend.\n");
+				WARN_ON(cw1200_reg_write_16(priv,
+						ST90TDS_CONTROL_REG_ID, 0));
+				priv->device_can_sleep = true;
+			}
+
+			atomic_set(&priv->bh_suspend, CW1200_BH_SUSPENDED);
+			wake_up(&priv->bh_evt_wq);
+			status = wait_event_interruptible(priv->bh_wq,
+					CW1200_BH_RESUME == atomic_read(
+						&priv->bh_suspend));
+			if (status < 0) {
+				wiphy_err(priv->hw->wiphy,
+					"%s: Failed to wait for resume: %ld.\n",
+					__func__, status);
+				break;
+			}
+			pr_debug("[BH] Device resume.\n");
+			atomic_set(&priv->bh_suspend, CW1200_BH_RESUMED);
+			wake_up(&priv->bh_evt_wq);
+			atomic_add(1, &priv->bh_rx);
+			goto done;
+		}
+
+	rx:
+		tx += pending_tx;
+		pending_tx = 0;
+
+		if (WARN_ON(cw1200_bh_read_ctrl_reg(
+				    priv, &ctrl_reg)))
+			break;
+
+		/* Don't bother trying to rx unless we have data to read */
+		if (ctrl_reg & ST90TDS_CONT_NEXT_LEN_MASK) {
+			ret = cw1200_bh_rx_helper(priv, &ctrl_reg, &tx);
+			if (ret < 0)
+				break;
+			/* Double up here if there's more data.. */
+			if (ctrl_reg & ST90TDS_CONT_NEXT_LEN_MASK) {
+				ret = cw1200_bh_rx_helper(priv, &ctrl_reg, &tx);
+				if (ret < 0)
+					break;
+			}
+		}
+
+	tx:
+		if (tx) {
+			tx = 0;
+
+			BUG_ON(priv->hw_bufs_used > priv->wsm_caps.numInpChBufs);
+			tx_burst = priv->wsm_caps.numInpChBufs - priv->hw_bufs_used;
+			tx_allowed = tx_burst > 0;
+
+			if (!tx_allowed) {
+				/* Buffers full.  Ensure we process tx after we handle rx.. */
+				pending_tx = tx;
+				goto done_rx;
+			}
+			ret = cw1200_bh_tx_helper(priv, &pending_tx, &tx_burst);
+			if (ret < 0)
+				break;
+			if (ret > 0) /* More to transmit */
+				tx = ret;
+
+			/* Re-read ctrl reg */
+			if (WARN_ON(cw1200_bh_read_ctrl_reg(
+					    priv, &ctrl_reg)))
+				break;
+		}
+
+	done_rx:
+		if (priv->bh_error)
+			break;
+		if (ctrl_reg & ST90TDS_CONT_NEXT_LEN_MASK)
+			goto rx;
+		if (tx)
+			goto tx;
+
+	done:
+#ifdef CONFIG_CW1200_POLL_IRQ
+		mod_timer(&priv->irqpoll_timer, jiffies + HZ/100);
+#else
+		/* Re-enable device interrupts */
+		if (priv->sbus_ops->irq_enable) {
+			priv->sbus_ops->lock(priv->sbus_priv);
+			priv->sbus_ops->irq_enable(priv->sbus_priv, 1);
+			priv->sbus_ops->unlock(priv->sbus_priv);
+		}
+#endif
+	}
+
+#ifdef CONFIG_CW1200_POLL_IRQ
+	del_timer_sync(&priv->irqpoll_timer);
+#else
+	/* Re-enable device interrupts? */
+	if (priv->sbus_ops->irq_enable) {
+		priv->sbus_ops->lock(priv->sbus_priv);
+		priv->sbus_ops->irq_enable(priv->sbus_priv, 1);
+		priv->sbus_ops->unlock(priv->sbus_priv);
+	}
+#endif
+
+	if (!term) {
+		pr_err("[BH] Fatal error, exiting.\n");
+		priv->bh_error = 1;
+		/* TODO: schedule_work(recovery) */
+#ifndef HAS_PUT_TASK_STRUCT
+		/* The only reason of having this stupid code here is
+		 * that __put_task_struct is not exported by kernel. */
+		for (;;) {
+			int status = wait_event_interruptible(priv->bh_wq, ({
+				term = atomic_xchg(&priv->bh_term, 0);
+				(term);
+				}));
+
+			if (status || term)
+				break;
+		}
+#endif
+	}
+	return 0;
+}
diff --git a/drivers/staging/cw1200/bh.h b/drivers/staging/cw1200/bh.h
new file mode 100644
index 0000000..fd8a8c5
--- /dev/null
+++ b/drivers/staging/cw1200/bh.h
@@ -0,0 +1,28 @@
+/*
+ * Device handling thread interface for mac80211 ST-Ericsson CW1200 drivers
+ *
+ * Copyright (c) 2010, ST-Ericsson
+ * Author: Dmitry Tarnyagin <dmitry.tarnyagin@stericsson.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.
+ */
+
+#ifndef CW1200_BH_H
+#define CW1200_BH_H
+
+/* extern */ struct cw1200_common;
+
+int cw1200_register_bh(struct cw1200_common *priv);
+void cw1200_unregister_bh(struct cw1200_common *priv);
+void cw1200_irq_handler(struct cw1200_common *priv);
+void cw1200_bh_wakeup(struct cw1200_common *priv);
+int cw1200_bh_suspend(struct cw1200_common *priv);
+int cw1200_bh_resume(struct cw1200_common *priv);
+/* Must be called from BH thread. */
+void cw1200_enable_powersave(struct cw1200_common *priv,
+			     bool enable);
+int wsm_release_tx_buffer(struct cw1200_common *priv, int count);
+
+#endif /* CW1200_BH_H */
-- 
1.7.11.7