Commit a7b66822 authored by Stefan Berger's avatar Stefan Berger Committed by Rajiv Andrade
Browse files

tpm_tis: Fix the probing for interrupts 



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: default avatarStefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: default avatarRajiv Andrade <srajiv@linux.vnet.ibm.com>
parent 20b87bbf

drivers/char/tpm/tpm.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

drivers/char/tpm/tpm_tis.c

+27 −6
Original line number Diff line number Diff line
@@ -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);
@@ -562,11 +565,17 @@ 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));

			if (request_irq
@@ -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;

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