/*
* ---------------------------------------------------------------------------
* FILE: bh.c
*
* PURPOSE:
* Provides an implementation for the driver bottom-half.
* It is part of the porting exercise in Linux.
*
* Copyright (C) 2005-2009 by Cambridge Silicon Radio Ltd.
*
* Refer to LICENSE.txt included with this source code for details on
* the license terms.
*
* ---------------------------------------------------------------------------
*/
#include "csr_wifi_hip_unifi.h"
#include "unifi_priv.h"
#include <linux/sched/rt.h>
/*
* ---------------------------------------------------------------------------
* uf_start_thread
*
* Helper function to start a new thread.
*
* Arguments:
* priv Pointer to OS driver structure for the device.
* thread Pointer to the thread object
* func The thread function
*
* Returns:
* 0 on success or else a Linux error code.
* ---------------------------------------------------------------------------
*/
int uf_start_thread(unifi_priv_t *priv,
struct uf_thread *thread, int (*func)(void *))
{
if (thread->thread_task != NULL) {
unifi_error(priv, "%s thread already started\n", thread->name);
return 0;
}
/* Start the kernel thread that handles all h/w accesses. */
thread->thread_task = kthread_run(func, priv, "%s", thread->name);
if (IS_ERR(thread->thread_task))
return PTR_ERR(thread->thread_task);
/* Module parameter overides the thread priority */
if (bh_priority != -1) {
if (bh_priority >= 0 && bh_priority <= MAX_RT_PRIO) {
struct sched_param param;
priv->bh_thread.prio = bh_priority;
unifi_trace(priv, UDBG1,
"%s thread (RT) priority = %d\n",
thread->name, bh_priority);
param.sched_priority = bh_priority;
sched_setscheduler(thread->thread_task,
SCHED_FIFO, ¶m);
} else if (bh_priority > MAX_RT_PRIO &&
bh_priority <= MAX_PRIO) {
priv->bh_thread.prio = bh_priority;
unifi_trace(priv, UDBG1, "%s thread priority = %d\n",
thread->name,
PRIO_TO_NICE(bh_priority));
set_user_nice(thread->thread_task,
PRIO_TO_NICE(bh_priority));
} else {
priv->bh_thread.prio = DEFAULT_PRIO;
unifi_warning(priv,
"%s thread unsupported (%d) priority\n",
thread->name, bh_priority);
}
} else
priv->bh_thread.prio = DEFAULT_PRIO;
unifi_trace(priv, UDBG2, "Started %s thread\n", thread->name);
return 0;
} /* uf_start_thread() */
/*
* ---------------------------------------------------------------------------
* uf_stop_thread
*
* Helper function to stop a thread.
*
* Arguments:
* priv Pointer to OS driver structure for the device.
* thread Pointer to the thread object
*
* Returns:
*
* ---------------------------------------------------------------------------
*/
void uf_stop_thread(unifi_priv_t *priv, struct uf_thread *thread)
{
if (!thread->thread_task) {
unifi_notice(priv, "%s thread is already stopped\n",
thread->name);
return;
}
unifi_trace(priv, UDBG2, "Stopping %s thread\n", thread->name);
kthread_stop(thread->thread_task);
thread->thread_task = NULL;
} /* uf_stop_thread() */
/*
* ---------------------------------------------------------------------------
* uf_wait_for_thread_to_stop
*
* Helper function to wait until a thread is stopped.
*
* Arguments:
* priv Pointer to OS driver structure for the device.
*
* Returns:
*
* ---------------------------------------------------------------------------
*/
void
uf_wait_for_thread_to_stop(unifi_priv_t *priv, struct uf_thread *thread)
{
/*
* kthread_stop() cannot handle the thread exiting while
* kthread_should_stop() is false, so sleep until kthread_stop()
* wakes us up
*/
unifi_trace(priv, UDBG2, "%s waiting for the stop signal.\n",
thread->name);
set_current_state(TASK_INTERRUPTIBLE);
if (!kthread_should_stop()) {
unifi_trace(priv, UDBG2, "%s schedule....\n", thread->name);
schedule();
}
thread->thread_task = NULL;
unifi_trace(priv, UDBG2, "%s exiting....\n", thread->name);
} /* uf_wait_for_thread_to_stop() */
/*
* ---------------------------------------------------------------------------
* handle_bh_error
*
* This function reports an error returned from the HIP core bottom-half.
* Normally, implemented during the porting exercise, passing the error
* to the SME using unifi_sys_wifi_off_ind().
* The SME will try to reset the device and go through
* the initialisation of the UniFi.
*
* Arguments:
* priv Pointer to OS driver structure for the device.
*
* Returns:
* None.
* ---------------------------------------------------------------------------
*/
static void
handle_bh_error(unifi_priv_t *priv)
{
netInterface_priv_t *interfacePriv;
u8 conf_param = CONFIG_IND_ERROR;
u8 interfaceTag;
/* Block unifi_run_bh() until the error has been handled. */
priv->bh_thread.block_thread = 1;
/* Consider UniFi to be uninitialised */
priv->init_progress = UNIFI_INIT_NONE;
/* Stop the network traffic */
for (interfaceTag = 0;
interfaceTag < CSR_WIFI_NUM_INTERFACES; interfaceTag++) {
interfacePriv = priv->interfacePriv[interfaceTag];
if (interfacePriv->netdev_registered)
netif_carrier_off(priv->netdev[interfaceTag]);
}
#ifdef CSR_NATIVE_LINUX
/* Force any client waiting on an mlme_wait_for_reply() to abort. */
uf_abort_mlme(priv);
/* Cancel any pending workqueue tasks */
flush_workqueue(priv->unifi_workqueue);
#endif /* CSR_NATIVE_LINUX */
unifi_error(priv,
"handle_bh_error: fatal error is reported to the SME.\n");
/* Notify the clients (SME or unifi_manager) for the error. */
ul_log_config_ind(priv, &conf_param, sizeof(u8));
} /* handle_bh_error() */
/*
* ---------------------------------------------------------------------------
* bh_thread_function
*
* All hardware access happens in this thread.
* This means there is no need for locks on the hardware and we don't need
* to worry about reentrancy with the SDIO library.
* Provides and example implementation on how to call unifi_bh(), which
* is part of the HIP core API.
*
* It processes the events generated by unifi_run_bh() to serialise calls
* to unifi_bh(). It also demonstrates how the timeout parameter passed in
* and returned from unifi_bh() needs to be handled.
*
* Arguments:
* arg Pointer to OS driver structure for the device.
*
* Returns:
* None.
*
* Notes:
* When the bottom half of the driver needs to process signals, events,
* or simply the host status (i.e sleep mode), it invokes unifi_run_bh().
* Since we need all SDIO transaction to be in a single thread, the
* unifi_run_bh() will wake up this thread to process it.
*
* ---------------------------------------------------------------------------
*/
static int bh_thread_function(void *arg)
{
unifi_priv_t *priv = (unifi_priv_t *)arg;
CsrResult csrResult;
long ret;
u32 timeout, t;
struct uf_thread *this_thread;
unifi_trace(priv, UDBG2, "bh_thread_function starting\n");
this_thread = &priv->bh_thread;
t = timeout = 0;
while (!kthread_should_stop()) {
/* wait until an error occurs, or we need to process something. */
unifi_trace(priv, UDBG3, "bh_thread goes to sleep.\n");
if (timeout > 0) {
/* Convert t in ms to jiffies */
t = msecs_to_jiffies(timeout);
ret = wait_event_interruptible_timeout(this_thread->wakeup_q,
(this_thread->wakeup_flag && !this_thread->block_thread) ||
kthread_should_stop(),
t);
timeout = (ret > 0) ? jiffies_to_msecs(ret) : 0;
} else {
ret = wait_event_interruptible(this_thread->wakeup_q,
(this_thread->wakeup_flag && !this_thread->block_thread) ||
kthread_should_stop());
}
if (kthread_should_stop()) {
unifi_trace(priv, UDBG2, "bh_thread: signalled to exit\n");
break;
}
if (ret < 0) {
unifi_notice(priv,
"bh_thread: wait_event returned %d, thread will exit\n",
ret);
uf_wait_for_thread_to_stop(priv, this_thread);
break;
}
this_thread->wakeup_flag = 0;
unifi_trace(priv, UDBG3, "bh_thread calls unifi_bh().\n");
CsrSdioClaim(priv->sdio);
csrResult = unifi_bh(priv->card, &timeout);
if(csrResult != CSR_RESULT_SUCCESS) {
if (csrResult == CSR_WIFI_HIP_RESULT_NO_DEVICE) {
CsrSdioRelease(priv->sdio);
uf_wait_for_thread_to_stop(priv, this_thread);
break;
}
/* Errors must be delivered to the error task */
handle_bh_error(priv);
}
CsrSdioRelease(priv->sdio);
}
/*
* I would normally try to call csr_sdio_remove_irq() here to make sure
* that we do not get any interrupts while this thread is not running.
* However, the MMC/SDIO driver tries to kill its' interrupt thread.
* The kernel threads implementation does not allow to kill threads
* from a signalled to stop thread.
* So, instead call csr_sdio_linux_remove_irq() always after calling
* uf_stop_thread() to kill this thread.
*/
unifi_trace(priv, UDBG2, "bh_thread exiting....\n");
return 0;
} /* bh_thread_function() */
/*
* ---------------------------------------------------------------------------
* uf_init_bh
*
* Helper function to start the bottom half of the driver.
* All we need to do here is start the I/O bh thread.
*
* Arguments:
* priv Pointer to OS driver structure for the device.
*
* Returns:
* 0 on success or else a Linux error code.
* ---------------------------------------------------------------------------
*/
int
uf_init_bh(unifi_priv_t *priv)
{
int r;
/* Enable mlme interface. */
priv->io_aborted = 0;
/* Start the BH thread */
r = uf_start_thread(priv, &priv->bh_thread, bh_thread_function);
if (r) {
unifi_error(priv,
"uf_init_bh: failed to start the BH thread.\n");
return r;
}
/* Allow interrupts */
r = csr_sdio_linux_install_irq(priv->sdio);
if (r) {
unifi_error(priv,
"uf_init_bh: failed to install the IRQ.\n");
uf_stop_thread(priv, &priv->bh_thread);
}
return r;
} /* uf_init_bh() */
/*
* ---------------------------------------------------------------------------
* unifi_run_bh
*
* Part of the HIP core lib API, implemented in the porting exercise.
* The bottom half of the driver calls this function when
* it wants to process anything that requires access to unifi.
* We need to call unifi_bh() which in this implementation is done
* by waking up the I/O thread.
*
* Arguments:
* ospriv Pointer to OS driver structure for the device.
*
* Returns:
* 0 on success or else a Linux error code.
*
* Notes:
* ---------------------------------------------------------------------------
*/
CsrResult unifi_run_bh(void *ospriv)
{
unifi_priv_t *priv = ospriv;
/*
* If an error has occurred, we discard silently all messages from the bh
* until the error has been processed and the unifi has been reinitialised.
*/
if (priv->bh_thread.block_thread == 1) {
unifi_trace(priv, UDBG3, "unifi_run_bh: discard message.\n");
/*
* Do not try to acknowledge a pending interrupt here.
* This function is called by unifi_send_signal() which in turn can be
* running in an atomic or 'disabled irq' level if a signal is sent
* from a workqueue task (i.e multicass addresses set).
* We can not hold the SDIO lock because it might sleep.
*/
return CSR_RESULT_FAILURE;
}
priv->bh_thread.wakeup_flag = 1;
/* wake up I/O thread */
wake_up_interruptible(&priv->bh_thread.wakeup_q);
return CSR_RESULT_SUCCESS;
} /* unifi_run_bh() */