[PATCH v9] tpm_tis: verify interrupt during init

[Scot Doyle]

Some machines, such as the Acer C720 and Toshiba CB35, have TPMs that do
not send IRQs while also having an ACPI TPM entry indicating that they
will be sent. These machines freeze on resume while the tpm_tis module
waits for an IRQ, eventually timing out.

When in interrupt mode, the tpm_tis module should receive an IRQ during
module init. Fall back to polling mode if none is received when expected.

Signed-off-by: Scot Doyle <lkml14@xxxxxxxxxxxxx>
Tested-by: Michael Mullin <masmullin@xxxxxxxxx>
Reviewed-By: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
---
 drivers/char/tpm/tpm_tis.c | 76 +++++++++++++++++++++++++++++++++++++---------
 1 file changed, 62 insertions(+), 14 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index 2c46734..bfe1f1a 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -75,6 +75,10 @@ enum tis_defaults {
 #define	TPM_DID_VID(l)			(0x0F00 | ((l) << 12))
 #define	TPM_RID(l)			(0x0F04 | ((l) << 12))

+struct priv_data {
+	bool irq_tested;
+};
+
 static LIST_HEAD(tis_chips);
 static DEFINE_MUTEX(tis_lock);

@@ -338,12 +342,27 @@ out_err:
 	return rc;
 }

+static void disable_interrupts(struct tpm_chip *chip)
+{
+	u32 intmask;
+	intmask =
+	    ioread32(chip->vendor.iobase +
+		     TPM_INT_ENABLE(chip->vendor.locality));
+	intmask |= TPM_INTF_CMD_READY_INT | TPM_INTF_LOCALITY_CHANGE_INT |
+		   TPM_INTF_DATA_AVAIL_INT | TPM_INTF_STS_VALID_INT;
+	iowrite32(intmask,
+		  chip->vendor.iobase +
+		  TPM_INT_ENABLE(chip->vendor.locality));
+	free_irq(chip->vendor.irq, chip);
+	chip->vendor.irq = 0;
+}
+
 /*
  * If interrupts are used (signaled by an irq set in the vendor structure)
  * tpm.c can skip polling for the data to be available as the interrupt is
  * waited for here
  */
-static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
+static int tpm_tis_send_main(struct tpm_chip *chip, u8 *buf, size_t len)
 {
 	int rc;
 	u32 ordinal;
@@ -373,6 +392,30 @@ out_err:
 	return rc;
 }

+static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
+{
+	int rc, irq;
+	struct priv_data *priv = chip->vendor.priv;
+
+	if (!chip->vendor.irq || priv->irq_tested)
+		return tpm_tis_send_main(chip, buf, len);
+
+	/* Verify receipt of the expected IRQ */
+	irq = chip->vendor.irq;
+	chip->vendor.irq = 0;
+	rc = tpm_tis_send_main(chip, buf, len);
+	chip->vendor.irq = irq;
+	if (!priv->irq_tested)
+		msleep(1);
+	if (!priv->irq_tested) {
+		disable_interrupts(chip);
+		dev_err(chip->dev,
+			FW_BUG "TPM interrupt not working, polling instead\n");
+	}
+	priv->irq_tested = true;
+	return rc;
+}
+
 struct tis_vendor_timeout_override {
 	u32 did_vid;
 	unsigned long timeout_us[4];
@@ -505,6 +548,7 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
 	if (interrupt == 0)
 		return IRQ_NONE;

+	((struct priv_data*)chip->vendor.priv)->irq_tested = true;
 	if (interrupt & TPM_INTF_DATA_AVAIL_INT)
 		wake_up_interruptible(&chip->vendor.read_queue);
 	if (interrupt & TPM_INTF_LOCALITY_CHANGE_INT)
@@ -534,9 +578,14 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
 	u32 vendor, intfcaps, intmask;
 	int rc, i, irq_s, irq_e, probe;
 	struct tpm_chip *chip;
+	struct priv_data *priv;

+	priv = devm_kzalloc(dev, sizeof(struct priv_data), GFP_KERNEL);
+	if (priv == NULL)
+		return -ENOMEM;
 	if (!(chip = tpm_register_hardware(dev, &tpm_tis)))
 		return -ENODEV;
+	chip->vendor.priv = priv;

 	chip->vendor.iobase = ioremap(start, len);
 	if (!chip->vendor.iobase) {
@@ -605,19 +654,6 @@ 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 */
-	if (tpm_get_timeouts(chip)) {
-		dev_err(dev, "Could not get TPM timeouts and durations\n");
-		rc = -ENODEV;
-		goto out_err;
-	}
-
-	if (tpm_do_selftest(chip)) {
-		dev_err(dev, "TPM self test failed\n");
-		rc = -ENODEV;
-		goto out_err;
-	}
-
 	/* INTERRUPT Setup */
 	init_waitqueue_head(&chip->vendor.read_queue);
 	init_waitqueue_head(&chip->vendor.int_queue);
@@ -719,6 +755,18 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
 		}
 	}

+	if (tpm_get_timeouts(chip)) {
+		dev_err(dev, "Could not get TPM timeouts and durations\n");
+		rc = -ENODEV;
+		goto out_err;
+	}
+
+	if (tpm_do_selftest(chip)) {
+		dev_err(dev, "TPM self test failed\n");
+		rc = -ENODEV;
+		goto out_err;
+	}
+
 	INIT_LIST_HEAD(&chip->vendor.list);
 	mutex_lock(&tis_lock);
 	list_add(&chip->vendor.list, &tis_chips);
-- 
2.1.0

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