[POWERPC] Convert adb.c to use kthread API and not spin on ADB requests

This converts adb.c to use the kthread API.

It also changes adb_request so that if the ADBREQ_SYNC flag is
specified, we now sleep waiting for the request to finish using an
on-stack completion rather than spinning.  To implement this, we now
require that if the ADBREQ_SYNC flag is set, the `done' parameter must
be NULL.  All of the existing callers of adb_request that pass
ADBREQ_SYNC appear to be in process context and have done == NULL.
Doing this allows us to get rid of an awful hack in adb_request()
where we used to test whether the request was coming from the adb
probe task and use a completion if it was, and otherwise spin.

This also gets rid of a static request block that was used if the req
parameter to adb_request was NULL.  None of the callers do that any
more, so the static request block is no longer necessary.

Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Paul Mackerras 2007-12-13 15:11:22 +11:00
Родитель 33f6e79406
Коммит c61dace9a1
1 изменённых файлов: 21 добавлений и 57 удалений

Просмотреть файл

@ -35,6 +35,7 @@
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/kthread.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>
@ -82,9 +83,7 @@ struct adb_driver *adb_controller;
BLOCKING_NOTIFIER_HEAD(adb_client_list);
static int adb_got_sleep;
static int adb_inited;
static pid_t adb_probe_task_pid;
static DECLARE_MUTEX(adb_probe_mutex);
static struct completion adb_probe_task_comp;
static int sleepy_trackpad;
static int autopoll_devs;
int __adb_probe_sync;
@ -126,16 +125,6 @@ static void printADBreply(struct adb_request *req)
}
#endif
static __inline__ void adb_wait_ms(unsigned int ms)
{
if (current->pid && adb_probe_task_pid &&
adb_probe_task_pid == current->pid)
msleep(ms);
else
mdelay(ms);
}
static int adb_scan_bus(void)
{
int i, highFree=0, noMovement;
@ -240,13 +229,10 @@ static int adb_scan_bus(void)
static int
adb_probe_task(void *x)
{
strcpy(current->comm, "kadbprobe");
printk(KERN_INFO "adb: starting probe task...\n");
do_adb_reset_bus();
printk(KERN_INFO "adb: finished probe task...\n");
adb_probe_task_pid = 0;
up(&adb_probe_mutex);
return 0;
@ -255,7 +241,7 @@ adb_probe_task(void *x)
static void
__adb_probe_task(struct work_struct *bullshit)
{
adb_probe_task_pid = kernel_thread(adb_probe_task, NULL, SIGCHLD | CLONE_KERNEL);
kthread_run(adb_probe_task, NULL, "kadbprobe");
}
static DECLARE_WORK(adb_reset_work, __adb_probe_task);
@ -341,7 +327,6 @@ int __init adb_init(void)
sleepy_trackpad = 1;
#endif /* CONFIG_PPC */
init_completion(&adb_probe_task_comp);
adbdev_init();
adb_reset_bus();
}
@ -366,7 +351,7 @@ do_adb_reset_bus(void)
if (sleepy_trackpad) {
/* Let the trackpad settle down */
adb_wait_ms(500);
msleep(500);
}
down(&adb_handler_sem);
@ -382,7 +367,7 @@ do_adb_reset_bus(void)
if (sleepy_trackpad) {
/* Let the trackpad settle down */
adb_wait_ms(1500);
msleep(1500);
}
if (!ret) {
@ -406,41 +391,27 @@ adb_poll(void)
adb_controller->poll();
}
static void
adb_probe_wakeup(struct adb_request *req)
static void adb_sync_req_done(struct adb_request *req)
{
complete(&adb_probe_task_comp);
}
struct completion *comp = req->arg;
/* Static request used during probe */
static struct adb_request adb_sreq;
static unsigned long adb_sreq_lock; // Use semaphore ! */
complete(comp);
}
int
adb_request(struct adb_request *req, void (*done)(struct adb_request *),
int flags, int nbytes, ...)
{
va_list list;
int i, use_sreq;
int i;
int rc;
struct completion comp;
if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
return -ENXIO;
if (nbytes < 1)
return -EINVAL;
if (req == NULL && (flags & ADBREQ_NOSEND))
return -EINVAL;
if (req == NULL) {
if (test_and_set_bit(0,&adb_sreq_lock)) {
printk("adb.c: Warning: contention on static request !\n");
return -EPERM;
}
req = &adb_sreq;
flags |= ADBREQ_SYNC;
use_sreq = 1;
} else
use_sreq = 0;
req->nbytes = nbytes+1;
req->done = done;
req->reply_expected = flags & ADBREQ_REPLY;
@ -453,25 +424,18 @@ adb_request(struct adb_request *req, void (*done)(struct adb_request *),
if (flags & ADBREQ_NOSEND)
return 0;
/* Synchronous requests send from the probe thread cause it to
* block. Beware that the "done" callback will be overriden !
*/
if ((flags & ADBREQ_SYNC) &&
(current->pid && adb_probe_task_pid &&
adb_probe_task_pid == current->pid)) {
req->done = adb_probe_wakeup;
rc = adb_controller->send_request(req, 0);
if (rc || req->complete)
goto bail;
wait_for_completion(&adb_probe_task_comp);
rc = 0;
goto bail;
/* Synchronous requests block using an on-stack completion */
if (flags & ADBREQ_SYNC) {
WARN_ON(done);
req->done = adb_sync_req_done;
req->arg = &comp;
init_completion(&comp);
}
rc = adb_controller->send_request(req, flags & ADBREQ_SYNC);
bail:
if (use_sreq)
clear_bit(0, &adb_sreq_lock);
rc = adb_controller->send_request(req, 0);
if ((flags & ADBREQ_SYNC) && !rc && !req->complete)
wait_for_completion(&comp);
return rc;
}