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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>
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@ -19,7 +19,7 @@
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*
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* Note, the TPM chip is not interrupt driven (only polling)
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* and can have very long timeouts (minutes!). Hence the unusual
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* calls to schedule_timeout.
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* calls to msleep.
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*
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*/
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@ -52,14 +52,6 @@ static void user_reader_timeout(unsigned long ptr)
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up(&chip->buffer_mutex);
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}
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void tpm_time_expired(unsigned long ptr)
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{
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int *exp = (int *) ptr;
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*exp = 1;
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}
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EXPORT_SYMBOL_GPL(tpm_time_expired);
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/*
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* Initialize the LPC bus and enable the TPM ports
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*/
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@ -135,6 +127,7 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
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ssize_t len;
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u32 count;
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__be32 *native_size;
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unsigned long stop;
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native_size = (__force __be32 *) (buf + 2);
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count = be32_to_cpu(*native_size);
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@ -155,28 +148,16 @@ static ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf,
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return len;
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}
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down(&chip->timer_manipulation_mutex);
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chip->time_expired = 0;
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init_timer(&chip->device_timer);
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chip->device_timer.function = tpm_time_expired;
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chip->device_timer.expires = jiffies + 2 * 60 * HZ;
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chip->device_timer.data = (unsigned long) &chip->time_expired;
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add_timer(&chip->device_timer);
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up(&chip->timer_manipulation_mutex);
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stop = jiffies + 2 * 60 * HZ;
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do {
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u8 status = inb(chip->vendor->base + 1);
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if ((status & chip->vendor->req_complete_mask) ==
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chip->vendor->req_complete_val) {
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down(&chip->timer_manipulation_mutex);
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del_singleshot_timer_sync(&chip->device_timer);
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up(&chip->timer_manipulation_mutex);
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goto out_recv;
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}
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(TPM_TIMEOUT);
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msleep(TPM_TIMEOUT); /* CHECK */
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rmb();
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} while (!chip->time_expired);
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} while (time_before(jiffies, stop));
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chip->vendor->cancel(chip);
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@ -453,10 +434,8 @@ ssize_t tpm_write(struct file * file, const char __user * buf,
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/* cannot perform a write until the read has cleared
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either via tpm_read or a user_read_timer timeout */
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while (atomic_read(&chip->data_pending) != 0) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(TPM_TIMEOUT);
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}
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while (atomic_read(&chip->data_pending) != 0)
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msleep(TPM_TIMEOUT);
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down(&chip->buffer_mutex);
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@ -25,7 +25,7 @@
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#define TPM_TIMEOUT msecs_to_jiffies(5)
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#define TPM_TIMEOUT 5 /* msecs */
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/* TPM addresses */
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#define TPM_ADDR 0x4E
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@ -78,7 +78,6 @@ static inline void tpm_write_index(int index, int value)
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outb(value & 0xFF, TPM_DATA);
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}
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extern void tpm_time_expired(unsigned long);
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extern int tpm_lpc_bus_init(struct pci_dev *, u16);
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extern int tpm_register_hardware(struct pci_dev *,
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@ -55,10 +55,7 @@
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*/
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static int wait_for_stat(struct tpm_chip *chip, u8 mask, u8 val, u8 * data)
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{
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int expired = 0;
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struct timer_list status_timer =
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TIMER_INITIALIZER(tpm_time_expired, jiffies + 10 * HZ,
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(unsigned long) &expired);
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unsigned long stop;
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/* status immediately available check */
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*data = inb(chip->vendor->base + NSC_STATUS);
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@ -66,17 +63,14 @@ static int wait_for_stat(struct tpm_chip *chip, u8 mask, u8 val, u8 * data)
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return 0;
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/* wait for status */
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add_timer(&status_timer);
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stop = jiffies + 10 * HZ;
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do {
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(TPM_TIMEOUT);
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msleep(TPM_TIMEOUT);
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*data = inb(chip->vendor->base + 1);
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if ((*data & mask) == val) {
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del_singleshot_timer_sync(&status_timer);
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if ((*data & mask) == val)
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return 0;
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}
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}
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while (!expired);
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while (time_before(jiffies, stop));
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return -EBUSY;
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}
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@ -84,10 +78,7 @@ static int wait_for_stat(struct tpm_chip *chip, u8 mask, u8 val, u8 * data)
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static int nsc_wait_for_ready(struct tpm_chip *chip)
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{
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int status;
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int expired = 0;
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struct timer_list status_timer =
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TIMER_INITIALIZER(tpm_time_expired, jiffies + 100,
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(unsigned long) &expired);
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unsigned long stop;
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/* status immediately available check */
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status = inb(chip->vendor->base + NSC_STATUS);
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@ -97,19 +88,16 @@ static int nsc_wait_for_ready(struct tpm_chip *chip)
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return 0;
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/* wait for status */
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add_timer(&status_timer);
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stop = jiffies + 100;
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do {
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set_current_state(TASK_UNINTERRUPTIBLE);
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schedule_timeout(TPM_TIMEOUT);
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msleep(TPM_TIMEOUT);
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status = inb(chip->vendor->base + NSC_STATUS);
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if (status & NSC_STATUS_OBF)
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status = inb(chip->vendor->base + NSC_DATA);
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if (status & NSC_STATUS_RDY) {
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del_singleshot_timer_sync(&status_timer);
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if (status & NSC_STATUS_RDY)
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return 0;
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}
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}
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while (!expired);
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while (time_before(jiffies, stop));
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dev_info(&chip->pci_dev->dev, "wait for ready failed\n");
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return -EBUSY;
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