tpm_tis: Refactor the interrupt setup

BugLink: http://bugs.launchpad.net/bugs/1398274

Now that the probe and run cases are merged together we can use a
much simpler setup flow where probe and normal setup are done with
exactly the same code.

Since the new flow always calls tpm_gen_interrupt to confirm the IRQ
there is also no longer any need to call tpm_get_timeouts twice.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Martin Wilck <Martin.Wilck@ts.fujitsu.com>
Tested-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Peter Huewe <peterhuewe@gmx.de>
(cherry picked from commit e3837e74)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/char/tpm/tpm_tis.c

@@ -99,7 +99,6 @@ static struct tpm_info tis_default_info = {
 #define	TPM_RID(l)			(0x0F04 | ((l) << 12))
 
 struct priv_data {
-	bool irq_probing;
 	bool irq_tested;
 };
 
@@ -462,12 +461,8 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
 	chip->vendor.irq = irq;
 	if (!priv->irq_tested)
 		msleep(1);
-	if (!priv->irq_tested) {
+	if (!priv->irq_tested)
 		disable_interrupts(chip);
-		if (!priv->irq_probing)
-			dev_err(chip->pdev, FW_BUG
-				"TPM interrupt not working, polling instead\n");
-	}
 	priv->irq_tested = true;
 	return rc;
 }
@@ -604,6 +599,80 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+/* Register the IRQ and issue a command that will cause an interrupt. If an
+ * irq is seen then leave the chip setup for IRQ operation, otherwise reverse
+ * everything and leave in polling mode. Returns 0 on success.
+ */
+static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask, int irq)
+{
+	struct priv_data *priv = chip->vendor.priv;
+	u8 original_int_vec;
+
+	if (devm_request_irq(chip->pdev, irq, tis_int_handler, IRQF_SHARED,
+			     chip->devname, chip) != 0) {
+		dev_info(chip->pdev, "Unable to request irq: %d for probe\n",
+			 irq);
+		return -1;
+	}
+	chip->vendor.irq = irq;
+
+	original_int_vec = ioread8(chip->vendor.iobase +
+				   TPM_INT_VECTOR(chip->vendor.locality));
+	iowrite8(irq,
+		 chip->vendor.iobase + TPM_INT_VECTOR(chip->vendor.locality));
+
+	/* Clear all existing */
+	iowrite32(ioread32(chip->vendor.iobase +
+			   TPM_INT_STATUS(chip->vendor.locality)),
+		  chip->vendor.iobase + TPM_INT_STATUS(chip->vendor.locality));
+
+	/* Turn on */
+	iowrite32(intmask | TPM_GLOBAL_INT_ENABLE,
+		  chip->vendor.iobase + TPM_INT_ENABLE(chip->vendor.locality));
+
+	priv->irq_tested = false;
+
+	/* Generate an interrupt by having the core call through to
+	 * tpm_tis_send
+	 */
+	if (chip->flags & TPM_CHIP_FLAG_TPM2)
+		tpm2_gen_interrupt(chip);
+	else
+		tpm_gen_interrupt(chip);
+
+	/* tpm_tis_send will either confirm the interrupt is working or it
+	 * will call disable_irq which undoes all of the above.
+	 */
+	if (!chip->vendor.irq) {
+		iowrite8(original_int_vec,
+			 chip->vendor.iobase +
+			     TPM_INT_VECTOR(chip->vendor.locality));
+		return 1;
+	}
+
+	return 0;
+}
+
+/* Try to find the IRQ the TPM is using. This is for legacy x86 systems that
+ * do not have ACPI/etc. We typically expect the interrupt to be declared if
+ * present.
+ */
+static void tpm_tis_probe_irq(struct tpm_chip *chip, u32 intmask)
+{
+	u8 original_int_vec;
+	int i;
+
+	original_int_vec = ioread8(chip->vendor.iobase +
+				   TPM_INT_VECTOR(chip->vendor.locality));
+
+	if (!original_int_vec) {
+		for (i = 3; i <= 15; i++)
+			if (!tpm_tis_probe_irq_single(chip, intmask, i))
+				return;
+	} else if (!tpm_tis_probe_irq_single(chip, intmask, original_int_vec))
+		return;
+}
+
 static bool interrupts = true;
 module_param(interrupts, bool, 0444);
 MODULE_PARM_DESC(interrupts, "Enable interrupts");
@@ -626,8 +695,7 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
 			acpi_handle acpi_dev_handle)
 {
 	u32 vendor, intfcaps, intmask;
-	int rc, i, irq_s, irq_e, probe;
-	int irq_r = -1;
+	int rc, probe;
 	struct tpm_chip *chip;
 	struct priv_data *priv;
 
@@ -735,98 +803,14 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
 	/* INTERRUPT Setup */
 	init_waitqueue_head(&chip->vendor.read_queue);
 	init_waitqueue_head(&chip->vendor.int_queue);
-
-	if (interrupts)
-		chip->vendor.irq = tpm_info->irq;
-	if (interrupts && !chip->vendor.irq) {
-		irq_s =
-		    ioread8(chip->vendor.iobase +
-			    TPM_INT_VECTOR(chip->vendor.locality));
-		irq_r = irq_s;
-		if (irq_s) {
-			irq_e = irq_s;
-		} else {
-			irq_s = 3;
-			irq_e = 15;
-		}
-
-		for (i = irq_s; i <= irq_e && chip->vendor.irq == 0; i++) {
-			iowrite8(i, chip->vendor.iobase +
-				 TPM_INT_VECTOR(chip->vendor.locality));
-			if (devm_request_irq
-			    (dev, i, tis_int_handler, IRQF_SHARED,
-			     chip->devname, chip) != 0) {
-				dev_info(chip->pdev,
-					 "Unable to request irq: %d for probe\n",
-					 i);
-				continue;
-			}
-			chip->vendor.irq = i;
-
-			/* Clear all existing */
-			iowrite32(ioread32
-				  (chip->vendor.iobase +
-				   TPM_INT_STATUS(chip->vendor.locality)),
-				  chip->vendor.iobase +
-				  TPM_INT_STATUS(chip->vendor.locality));
-
-			/* Turn on */
-			iowrite32(intmask | TPM_GLOBAL_INT_ENABLE,
-				  chip->vendor.iobase +
-				  TPM_INT_ENABLE(chip->vendor.locality));
-
-			priv->irq_tested = false;
-			priv->irq_probing = true;
-
-			/* Generate Interrupts */
-			if (chip->flags & TPM_CHIP_FLAG_TPM2)
-				tpm2_gen_interrupt(chip);
-			else
-				tpm_gen_interrupt(chip);
-
-			priv->irq_probing = false;
-
-			/* tpm_tis_send will either confirm the interrupt is
-			 * working or it will call disable_irq which undoes
-			 * all of the above.
-			 */
-			if (chip->vendor.irq)
-				break;
-		}
-		if (!chip->vendor.irq)
-			iowrite8(irq_r, chip->vendor.iobase +
-				 TPM_INT_VECTOR(chip->vendor.locality));
-	}
-	if (chip->vendor.irq && !priv->irq_tested) {
-		iowrite8(chip->vendor.irq,
-			 chip->vendor.iobase +
-			 TPM_INT_VECTOR(chip->vendor.locality));
-		if (devm_request_irq
-		    (dev, chip->vendor.irq, tis_int_handler, IRQF_SHARED,
-		     chip->devname, chip) != 0) {
-			dev_info(chip->pdev,
-				 "Unable to request irq: %d for use\n",
-				 chip->vendor.irq);
-			chip->vendor.irq = 0;
-		} else {
-			/* Clear all existing */
-			iowrite32(ioread32
-				  (chip->vendor.iobase +
-				   TPM_INT_STATUS(chip->vendor.locality)),
-				  chip->vendor.iobase +
-				  TPM_INT_STATUS(chip->vendor.locality));
-
-			/* Turn on */
-			iowrite32(intmask | TPM_GLOBAL_INT_ENABLE,
-				  chip->vendor.iobase +
-				  TPM_INT_ENABLE(chip->vendor.locality));
-		}
-	}
-
-	if (tpm_get_timeouts(chip)) {
-		dev_err(dev, "Could not get TPM timeouts and durations\n");
-		rc = -ENODEV;
-		goto out_err;
+	if (interrupts) {
+		if (tpm_info->irq) {
+			tpm_tis_probe_irq_single(chip, intmask, tpm_info->irq);
+			if (!chip->vendor.irq)
+				dev_err(chip->pdev, FW_BUG
+					"TPM interrupt not working, polling instead\n");
+		} else
+			tpm_tis_probe_irq(chip, intmask);
 	}
 
 	if (chip->flags & TPM_CHIP_FLAG_TPM2) {