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Subject[patch 5/8] tpm_tis: Fix the probing for interrupts
This patch fixes several aspects of the probing for interrupts.

I am reading the TPM's timeouts before probing for the interrupts. The
tpm_get_timeouts() function is invoked in polling mode and gets the proper
timeouts from the TPM so that we don't need to fall back to 2 minutes timeouts
for short duration commands while the interrupt probing is happening.

I am introducing a variable probed_irq into the vendor structure that gets the
irq number if an interrupt is received while the the tpm_gen_interrupt()
function is run in polling mode during interrupt probing. Previously some
parts of tpm_gen_interrupt() were run in polling mode, then the irq variable
was set in the interrupt handler when an interrupt was received and execution
of tpm_gen_interrupt() ended up switching over to interrupt mode.
tpm_gen_interrupt() execution ended up on an event queue where it eventually
timed out since the probing handler doesn't wake any queues.

Before calling into free_irq() I am clearing all interrupt flags that may have
been set by the TPM. The reason is that free_irq() will call into the probing
interrupt handler and may otherwise fool us into thinking that a real interrupt
happened (because we see the flags as being set) while the TPM's interrupt line
is not even connected to anything on the motherboard. This solves a problem
one one machine I did testing.

Further, if a TPM claims to use a specifc interrupt, also make sure that that
interrupt is working by running the probing on it as well. If a TPM indicates
that it does not use a specific interrupt (returns '0'), probe all interrupts
from 3 to 15.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

---
drivers/char/tpm/tpm.h | 1 +
drivers/char/tpm/tpm_tis.c | 33 +++++++++++++++++++++++++++------
2 files changed, 28 insertions(+), 6 deletions(-)
Index: linux-2.6/drivers/char/tpm/tpm_tis.c
===================================================================
--- linux-2.6.orig/drivers/char/tpm/tpm_tis.c
+++ linux-2.6/drivers/char/tpm/tpm_tis.c
@@ -436,7 +436,7 @@ static irqreturn_t tis_int_probe(int irq
if (interrupt == 0)
return IRQ_NONE;

- chip->vendor.irq = irq;
+ chip->vendor.probed_irq = irq;

/* Clear interrupts handled with TPM_EOI */
iowrite32(interrupt,
@@ -484,7 +484,7 @@ static int tpm_tis_init(struct device *d
resource_size_t len, unsigned int irq)
{
u32 vendor, intfcaps, intmask;
- int rc, i;
+ int rc, i, irq_s, irq_e;
struct tpm_chip *chip;

if (!(chip = tpm_register_hardware(dev, &tpm_tis)))
@@ -542,6 +542,9 @@ static int tpm_tis_init(struct device *d
if (intfcaps & TPM_INTF_DATA_AVAIL_INT)
dev_dbg(dev, "\tData Avail Int Support\n");

+ /* get the timeouts before testing for irqs */
+ tpm_get_timeouts(chip);
+
/* INTERRUPT Setup */
init_waitqueue_head(&chip->vendor.read_queue);
init_waitqueue_head(&chip->vendor.int_queue);
@@ -560,13 +563,19 @@ static int tpm_tis_init(struct device *d
if (interrupts)
chip->vendor.irq = irq;
if (interrupts && !chip->vendor.irq) {
- chip->vendor.irq =
+ irq_s =
ioread8(chip->vendor.iobase +
TPM_INT_VECTOR(chip->vendor.locality));
+ if (irq_s) {
+ irq_e = irq_s;
+ } else {
+ irq_s = 3;
+ irq_e = 15;
+ }

- for (i = 3; i < 16 && chip->vendor.irq == 0; i++) {
+ for (i = irq_s; i <= irq_e && chip->vendor.irq == 0; i++) {
iowrite8(i, chip->vendor.iobase +
- TPM_INT_VECTOR(chip->vendor.locality));
+ TPM_INT_VECTOR(chip->vendor.locality));
if (request_irq
(i, tis_int_probe, IRQF_SHARED,
chip->vendor.miscdev.name, chip) != 0) {
@@ -588,9 +597,22 @@ static int tpm_tis_init(struct device *d
chip->vendor.iobase +
TPM_INT_ENABLE(chip->vendor.locality));

+ chip->vendor.probed_irq = 0;
+
/* Generate Interrupts */
tpm_gen_interrupt(chip);

+ chip->vendor.irq = chip->vendor.probed_irq;
+
+ /* free_irq will call into tis_int_probe;
+ clear all irqs we haven't seen while doing
+ tpm_gen_interrupt */
+ iowrite32(ioread32
+ (chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality)),
+ chip->vendor.iobase +
+ TPM_INT_STATUS(chip->vendor.locality));
+
/* Turn off */
iowrite32(intmask,
chip->vendor.iobase +
@@ -629,7 +651,6 @@ static int tpm_tis_init(struct device *d
list_add(&chip->vendor.list, &tis_chips);
spin_unlock(&tis_lock);

- tpm_get_timeouts(chip);
tpm_continue_selftest(chip);

return 0;
Index: linux-2.6/drivers/char/tpm/tpm.h
===================================================================
--- linux-2.6.orig/drivers/char/tpm/tpm.h
+++ linux-2.6/drivers/char/tpm/tpm.h
@@ -69,6 +69,7 @@ struct tpm_vendor_specific {
unsigned long base; /* TPM base address */

int irq;
+ int probed_irq;

int region_size;
int have_region;


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