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tpm_tis: Fix the probing for interrupts

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This patch fixes several aspects of the probing for interrupts.

This patch reads 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.

This patch introduces 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() clear 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
on one machine I did testing on (Thinkpad T60).

If a TPM claims to use a specifc interrupt, the probing is done as well
to verify that the interrupt is actually working. 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>
Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
This commit is contained in:
Stefan Berger 2011-03-30 12:13:32 -04:00 committed by Rajiv Andrade
parent 20b87bbfad
commit a7b66822b2
2 changed files with 28 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/char/tpm/tpm.h
View File

@ -71,6 +71,7 @@ struct tpm_vendor_specific {
unsigned long base; /* TPM base address */
int irq;
int probed_irq;
int region_size;
int have_region;

33
drivers/char/tpm/tpm_tis.c
View File

@ -438,7 +438,7 @@ static irqreturn_t tis_int_probe(int irq, void *dev_id)
if (interrupt == 0)
return IRQ_NONE;
chip->vendor.irq = irq;
chip->vendor.probed_irq = irq;
/* Clear interrupts handled with TPM_EOI */
iowrite32(interrupt,
@ -486,7 +486,7 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
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)))
@ -544,6 +544,9 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
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);
@ -562,13 +565,19 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
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) {
@ -590,9 +599,22 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
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 +
@ -631,7 +653,6 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
list_add(&chip->vendor.list, &tis_chips);
spin_unlock(&tis_lock);
tpm_get_timeouts(chip);
tpm_continue_selftest(chip);
return 0;