/* cyanblkdev_queue.h - Antioch Linux Block Driver queue source file
## ===========================
## Copyright (C) 2010 Cypress Semiconductor
##
## This program is free software; you can redistribute it and/or
## modify it under the terms of the GNU General Public License
## as published by the Free Software Foundation; either version 2
## of the License, or (at your option) any later version.
##
## 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.
## ===========================
*/
/*
* Request queue handling for Antioch block device driver.
* Based on the mmc queue handling code by Russell King in the
* linux 2.6.10 kernel.
*/
/*
* linux/drivers/mmc/mmc_queue.c
*
* Copyright (C) 2003 Russell King, All Rights Reserved.
*
* 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 <linux/blkdev.h>
#include "cyasblkdev_queue.h"
#define CYASBLKDEV_QUEUE_EXIT (1 << 0)
#define CYASBLKDEV_QUEUE_SUSPENDED (1 << 1)
#define CY_AS_USE_ASYNC_API
/* print flags by name */
const char *rq_flag_bit_names[] = {
"REQ_RW", /* not set, read. set, write */
"REQ_FAILFAST", /* no low level driver retries */
"REQ_SORTED", /* elevator knows about this request */
"REQ_SOFTBARRIER", /* may not be passed by ioscheduler */
"REQ_HARDBARRIER", /* may not be passed by drive either */
"REQ_FUA", /* forced unit access */
"REQ_NOMERGE", /* don't touch this for merging */
"REQ_STARTED", /* drive already may have started this one */
"REQ_DONTPREP", /* don't call prep for this one */
"REQ_QUEUED", /* uses queueing */
"REQ_ELVPRIV", /* elevator private data attached */
"REQ_FAILED", /* set if the request failed */
"REQ_QUIET", /* don't worry about errors */
"REQ_PREEMPT", /* set for "ide_preempt" requests */
"REQ_ORDERED_COLOR",/* is before or after barrier */
"REQ_RW_SYNC", /* request is sync (O_DIRECT) */
"REQ_ALLOCED", /* request came from our alloc pool */
"REQ_RW_META", /* metadata io request */
"REQ_COPY_USER", /* contains copies of user pages */
"REQ_NR_BITS", /* stops here */
};
void verbose_rq_flags(int flags)
{
int i;
uint32_t j;
j = 1;
for (i = 0; i < 32; i++) {
if (flags & j)
DBGPRN("<1>%s", rq_flag_bit_names[i]);
j = j << 1;
}
}
/*
* Prepare a -BLK_DEV request. Essentially, this means passing the
* preparation off to the media driver. The media driver will
* create request to CyAsDev.
*/
static int cyasblkdev_prep_request(
struct request_queue *q, struct request *req)
{
DBGPRN_FUNC_NAME;
/* we only like normal block requests.*/
if (req->cmd_type != REQ_TYPE_FS && !(req->cmd_flags & REQ_DISCARD)) {
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message("%s:%x bad request received\n",
__func__, current->pid);
#endif
blk_dump_rq_flags(req, "cyasblkdev bad request");
return BLKPREP_KILL;
}
req->cmd_flags |= REQ_DONTPREP;
return BLKPREP_OK;
}
/* queue worker thread */
static int cyasblkdev_queue_thread(void *d)
{
DECLARE_WAITQUEUE(wait, current);
struct cyasblkdev_queue *bq = d;
struct request_queue *q = bq->queue;
u32 qth_pid;
DBGPRN_FUNC_NAME;
/*
* set iothread to ensure that we aren't put to sleep by
* the process freezing. we handle suspension ourselves.
*/
daemonize("cyasblkdev_queue_thread");
/* signal to queue_init() so it could contnue */
complete(&bq->thread_complete);
down(&bq->thread_sem);
add_wait_queue(&bq->thread_wq, &wait);
qth_pid = current->pid;
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s:%x started, bq:%p, q:%p\n", __func__, qth_pid, bq, q);
#endif
do {
struct request *req = NULL;
/* the thread wants to be woken up by signals as well */
set_current_state(TASK_INTERRUPTIBLE);
spin_lock_irq(q->queue_lock);
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s: for bq->queue is null\n", __func__);
#endif
if (!bq->req) {
/* chk if queue is plugged */
if (!blk_queue_plugged(q)) {
bq->req = req = blk_fetch_request(q);
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s: blk_fetch_request:%x\n",
__func__, (uint32_t)req);
#endif
} else {
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s: queue plugged, "
"skip blk_fetch()\n", __func__);
#endif
}
}
spin_unlock_irq(q->queue_lock);
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s: checking if request queue is null\n", __func__);
#endif
if (!req) {
if (bq->flags & CYASBLKDEV_QUEUE_EXIT) {
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s:got QUEUE_EXIT flag\n", __func__);
#endif
break;
}
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s: request queue is null, goto sleep, "
"thread_sem->count=%d\n",
__func__, bq->thread_sem.count);
if (spin_is_locked(q->queue_lock)) {
cy_as_hal_print_message("%s: queue_lock "
"is locked, need to release\n", __func__);
spin_unlock(q->queue_lock);
if (spin_is_locked(q->queue_lock))
cy_as_hal_print_message(
"%s: unlock did not work\n",
__func__);
} else {
cy_as_hal_print_message(
"%s: checked lock, is not locked\n",
__func__);
}
#endif
up(&bq->thread_sem);
/* yields to the next rdytorun proc,
* then goes back to sleep*/
schedule();
down(&bq->thread_sem);
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s: wake_up,continue\n",
__func__);
#endif
continue;
}
/* new req received, issue it to the driver */
set_current_state(TASK_RUNNING);
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s: issued a RQ:%x\n",
__func__, (uint32_t)req);
#endif
bq->issue_fn(bq, req);
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s: bq->issue_fn() returned\n",
__func__);
#endif
} while (1);
set_current_state(TASK_RUNNING);
remove_wait_queue(&bq->thread_wq, &wait);
up(&bq->thread_sem);
complete_and_exit(&bq->thread_complete, 0);
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message("%s: is finished\n", __func__);
#endif
return 0;
}
/*
* Generic request handler. it is called for any queue on a
* particular host. When the host is not busy, we look for a request
* on any queue on this host, and attempt to issue it. This may
* not be the queue we were asked to process.
*/
static void cyasblkdev_request(struct request_queue *q)
{
struct cyasblkdev_queue *bq = q->queuedata;
DBGPRN_FUNC_NAME;
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message(
"%s new request on cyasblkdev_queue_t bq:=%x\n",
__func__, (uint32_t)bq);
#endif
if (!bq->req) {
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message("%s wake_up(&bq->thread_wq)\n",
__func__);
#endif
/* wake up cyasblkdev_queue worker thread*/
wake_up(&bq->thread_wq);
} else {
#ifndef WESTBRIDGE_NDEBUG
cy_as_hal_print_message("%s: don't wake Q_thr, bq->req:%x\n",
__func__, (uint32_t)bq->req);
#endif
}
}
/*
* cyasblkdev_init_queue - initialise a queue structure.
* @bq: cyasblkdev queue
* @dev: CyAsDeviceHandle to attach this queue
* @lock: queue lock
*
* Initialise a cyasblkdev_request queue.
*/
/* MAX NUMBER OF SECTORS PER REQUEST **/
#define Q_MAX_SECTORS 128
/* MAX NUMBER OF PHYS SEGMENTS (entries in the SG list)*/
#define Q_MAX_SGS 16
int cyasblkdev_init_queue(struct cyasblkdev_queue *bq, spinlock_t *lock)
{
int ret;
DBGPRN_FUNC_NAME;
/* 1st param is a function that wakes up the queue thread */
bq->queue = blk_init_queue(cyasblkdev_request, lock);
if (!bq->queue)
return -ENOMEM;
blk_queue_prep_rq(bq->queue, cyasblkdev_prep_request);
blk_queue_bounce_limit(bq->queue, BLK_BOUNCE_ANY);
blk_queue_max_hw_sectors(bq->queue, Q_MAX_SECTORS);
/* As of now, we have the HAL/driver support to
* merge scattered segments and handle them simultaneously.
* so, setting the max_phys_segments to 8. */
/*blk_queue_max_phys_segments(bq->queue, Q_MAX_SGS);
blk_queue_max_hw_segments(bq->queue, Q_MAX_SGS);*/
blk_queue_max_segments(bq->queue, Q_MAX_SGS);
/* should be < then HAL can handle */
blk_queue_max_segment_size(bq->queue, 512*Q_MAX_SECTORS);
bq->queue->queuedata = bq;
bq->req = NULL;
init_completion(&bq->thread_complete);
init_waitqueue_head(&bq->thread_wq);
sema_init(&bq->thread_sem, 1);
ret = kernel_thread(cyasblkdev_queue_thread, bq, CLONE_KERNEL);
if (ret >= 0) {
/* wait until the thread is spawned */
wait_for_completion(&bq->thread_complete);
/* reinitialize the completion */
init_completion(&bq->thread_complete);
ret = 0;
goto out;
}
out:
return ret;
}
EXPORT_SYMBOL(cyasblkdev_init_queue);
/*called from blk_put() */
void cyasblkdev_cleanup_queue(struct cyasblkdev_queue *bq)
{
DBGPRN_FUNC_NAME;
bq->flags |= CYASBLKDEV_QUEUE_EXIT;
wake_up(&bq->thread_wq);
wait_for_completion(&bq->thread_complete);
blk_cleanup_queue(bq->queue);
}
EXPORT_SYMBOL(cyasblkdev_cleanup_queue);
/**
* cyasblkdev_queue_suspend - suspend a CyAsBlkDev request queue
* @bq: CyAsBlkDev queue to suspend
*
* Stop the block request queue, and wait for our thread to
* complete any outstanding requests. This ensures that we
* won't suspend while a request is being processed.
*/
void cyasblkdev_queue_suspend(struct cyasblkdev_queue *bq)
{
struct request_queue *q = bq->queue;
unsigned long flags;
DBGPRN_FUNC_NAME;
if (!(bq->flags & CYASBLKDEV_QUEUE_SUSPENDED)) {
bq->flags |= CYASBLKDEV_QUEUE_SUSPENDED;
spin_lock_irqsave(q->queue_lock, flags);
blk_stop_queue(q);
spin_unlock_irqrestore(q->queue_lock, flags);
down(&bq->thread_sem);
}
}
EXPORT_SYMBOL(cyasblkdev_queue_suspend);
/*cyasblkdev_queue_resume - resume a previously suspended
* CyAsBlkDev request queue @bq: CyAsBlkDev queue to resume */
void cyasblkdev_queue_resume(struct cyasblkdev_queue *bq)
{
struct request_queue *q = bq->queue;
unsigned long flags;
DBGPRN_FUNC_NAME;
if (bq->flags & CYASBLKDEV_QUEUE_SUSPENDED) {
bq->flags &= ~CYASBLKDEV_QUEUE_SUSPENDED;
up(&bq->thread_sem);
spin_lock_irqsave(q->queue_lock, flags);
blk_start_queue(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
}
EXPORT_SYMBOL(cyasblkdev_queue_resume);
/*[]*/
