[PATCH] char/tpm: use msleep(), clean-up timers,
The TPM driver unnecessarily uses timers when it simply needs to maintain a
maximum delay via time_before(). msleep() is used instead of
schedule_timeout() to guarantee the task delays as expected. While
compile-testing, I found a typo in the driver, using tpm_chp instead of
tpm_chip. Remove the now unused timer callback function and change
TPM_TIMEOUT's units to milliseconds. Patch is compile-tested.
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Acked-by: Kylene Hall <kjhall@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 8ce508b..c937ea2 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -19,7 +19,7 @@
*
* Note, the TPM chip is not interrupt driven (only polling)
* and can have very long timeouts (minutes!). Hence the unusual
- * calls to schedule_timeout.
+ * calls to msleep.
*
*/
@@ -52,14 +52,6 @@
up(&chip->buffer_mutex);
}
-void tpm_time_expired(unsigned long ptr)
-{
- int *exp = (int *) ptr;
- *exp = 1;
-}
-
-EXPORT_SYMBOL_GPL(tpm_time_expired);
-
/*
* Initialize the LPC bus and enable the TPM ports
*/
@@ -135,6 +127,7 @@
ssize_t len;
u32 count;
__be32 *native_size;
+ unsigned long stop;
native_size = (__force __be32 *) (buf + 2);
count = be32_to_cpu(*native_size);
@@ -155,28 +148,16 @@
return len;
}
- down(&chip->timer_manipulation_mutex);
- chip->time_expired = 0;
- init_timer(&chip->device_timer);
- chip->device_timer.function = tpm_time_expired;
- chip->device_timer.expires = jiffies + 2 * 60 * HZ;
- chip->device_timer.data = (unsigned long) &chip->time_expired;
- add_timer(&chip->device_timer);
- up(&chip->timer_manipulation_mutex);
-
+ stop = jiffies + 2 * 60 * HZ;
do {
u8 status = inb(chip->vendor->base + 1);
if ((status & chip->vendor->req_complete_mask) ==
chip->vendor->req_complete_val) {
- down(&chip->timer_manipulation_mutex);
- del_singleshot_timer_sync(&chip->device_timer);
- up(&chip->timer_manipulation_mutex);
goto out_recv;
}
- set_current_state(TASK_UNINTERRUPTIBLE);
- schedule_timeout(TPM_TIMEOUT);
+ msleep(TPM_TIMEOUT); /* CHECK */
rmb();
- } while (!chip->time_expired);
+ } while (time_before(jiffies, stop));
chip->vendor->cancel(chip);
@@ -453,10 +434,8 @@
/* cannot perform a write until the read has cleared
either via tpm_read or a user_read_timer timeout */
- while (atomic_read(&chip->data_pending) != 0) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- schedule_timeout(TPM_TIMEOUT);
- }
+ while (atomic_read(&chip->data_pending) != 0)
+ msleep(TPM_TIMEOUT);
down(&chip->buffer_mutex);