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[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>
This commit is contained in:
Nishanth Aravamudan 2005-06-23 22:01:47 -07:00 committed by Linus Torvalds
parent 6a94f92097
commit 700d8bdcd0
3 changed files with 18 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
drivers/char/tpm/tpm.c
View File

@ -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 @@ static void user_reader_timeout(unsigned long ptr)
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 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
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 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
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 @@ ssize_t tpm_write(struct file * file, const char __user * buf,
/* 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);

3
drivers/char/tpm/tpm.h
View File

@ -25,7 +25,7 @@
#include <linux/fs.h>
#include <linux/miscdevice.h>
#define TPM_TIMEOUT msecs_to_jiffies(5)
#define TPM_TIMEOUT 5 /* msecs */
/* TPM addresses */
#define TPM_ADDR 0x4E
@ -78,7 +78,6 @@ static inline void tpm_write_index(int index, int value)
outb(value & 0xFF, TPM_DATA);
}
extern void tpm_time_expired(unsigned long);
extern int tpm_lpc_bus_init(struct pci_dev *, u16);
extern int tpm_register_hardware(struct pci_dev *,

32
drivers/char/tpm/tpm_nsc.c
View File

@ -55,10 +55,7 @@
*/
static int wait_for_stat(struct tpm_chip *chip, u8 mask, u8 val, u8 * data)
{
int expired = 0;
struct timer_list status_timer =
TIMER_INITIALIZER(tpm_time_expired, jiffies + 10 * HZ,
(unsigned long) &expired);
unsigned long stop;
/* status immediately available check */
*data = inb(chip->vendor->base + NSC_STATUS);
@ -66,17 +63,14 @@ static int wait_for_stat(struct tpm_chip *chip, u8 mask, u8 val, u8 * data)
return 0;
/* wait for status */
add_timer(&status_timer);
stop = jiffies + 10 * HZ;
do {
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(TPM_TIMEOUT);
msleep(TPM_TIMEOUT);
*data = inb(chip->vendor->base + 1);
if ((*data & mask) == val) {
del_singleshot_timer_sync(&status_timer);
if ((*data & mask) == val)
return 0;
}
}
while (!expired);
while (time_before(jiffies, stop));
return -EBUSY;
}
@ -84,10 +78,7 @@ static int wait_for_stat(struct tpm_chip *chip, u8 mask, u8 val, u8 * data)
static int nsc_wait_for_ready(struct tpm_chip *chip)
{
int status;
int expired = 0;
struct timer_list status_timer =
TIMER_INITIALIZER(tpm_time_expired, jiffies + 100,
(unsigned long) &expired);
unsigned long stop;
/* status immediately available check */
status = inb(chip->vendor->base + NSC_STATUS);
@ -97,19 +88,16 @@ static int nsc_wait_for_ready(struct tpm_chip *chip)
return 0;
/* wait for status */
add_timer(&status_timer);
stop = jiffies + 100;
do {
set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(TPM_TIMEOUT);
msleep(TPM_TIMEOUT);
status = inb(chip->vendor->base + NSC_STATUS);
if (status & NSC_STATUS_OBF)
status = inb(chip->vendor->base + NSC_DATA);
if (status & NSC_STATUS_RDY) {
del_singleshot_timer_sync(&status_timer);
if (status & NSC_STATUS_RDY)
return 0;
}
}
while (!expired);
while (time_before(jiffies, stop));
dev_info(&chip->pci_dev->dev, "wait for ready failed\n");
return -EBUSY;