I have tested this patch and agree that using msleep is the right. Please
apply this patch to the tpm driver. One hunk might fail b/c the
typo has been fixed already.
Thanks,
Kylie Hall
On Fri, 11 Mar 2005, Nishanth Aravamudan wrote:
> Not sure what happened to the original mail, but I'm not seeing it
> yet...
>
> On Wed, Mar 09, 2005 at 04:42:01PM -0800, Greg KH wrote:
> > ChangeSet 1.2035, 2005/03/09 10:12:19-08:00, [email protected]
> >
> > [PATCH] Add TPM hardware enablement driver
> >
> > This patch is a device driver to enable new hardware. The new hardware is
> > the TPM chip as described by specifications at
> > <http://www.trustedcomputinggroup.org>. The TPM chip will enable you to
> > use hardware to securely store and protect your keys and personal data.
> > To use the chip according to the specification, you will need the Trusted
> > Software Stack (TSS) of which an implementation for Linux is available at:
> > <http://sourceforge.net/projects/trousers>.
>
> Here is a patch that removes all callers of schedule_timeout() as I
> previously mentioned:
>
> Description: 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 <[email protected]>
>
> diff -urpN 2.6.11-v/drivers/char/tpm/tpm.c 2.6.11/drivers/char/tpm/tpm.c
> --- 2.6.11-v/drivers/char/tpm/tpm.c 2005-03-10 10:50:00.000000000 -0800
> +++ 2.6.11/drivers/char/tpm/tpm.c 2005-03-10 11:00:50.000000000 -0800
> @@ -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
> 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_c
> 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_c
> 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);
> @@ -219,7 +200,7 @@ static ssize_t show_pcrs(struct device *
> int i, j, index, num_pcrs;
> char *str = buf;
>
> - struct tpm_chp *chip =
> + struct tpm_chip *chip =
> pci_get_drvdata(container_of(dev, struct pci_dev, dev));
> if (chip == NULL)
> return -ENODEV;
> @@ -450,10 +431,8 @@ ssize_t tpm_write(struct file * file, co
>
> /* 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);
>
> diff -urpN 2.6.11-v/drivers/char/tpm/tpm.h 2.6.11/drivers/char/tpm/tpm.h
> --- 2.6.11-v/drivers/char/tpm/tpm.h 2005-03-10 10:50:00.000000000 -0800
> +++ 2.6.11/drivers/char/tpm/tpm.h 2005-03-10 10:58:12.000000000 -0800
> @@ -24,7 +24,7 @@
> #include <linux/delay.h>
> #include <linux/miscdevice.h>
>
> -#define TPM_TIMEOUT msecs_to_jiffies(5)
> +#define TPM_TIMEOUT 5 /* msecs */
>
> /* TPM addresses */
> #define TPM_ADDR 0x4E
> @@ -77,7 +77,6 @@ static inline void tpm_write_index(int i
> 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 *,
> diff -urpN 2.6.11-v/drivers/char/tpm/tpm_nsc.c 2.6.11/drivers/char/tpm/tpm_nsc.c
> --- 2.6.11-v/drivers/char/tpm/tpm_nsc.c 2005-03-10 10:50:00.000000000 -0800
> +++ 2.6.11/drivers/char/tpm/tpm_nsc.c 2005-03-10 10:56:54.000000000 -0800
> @@ -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
> 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
> 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
> 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;
>
>
-
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