tpm_tis: reserve chip for duration of tpm_tis_core_init

Instead of repeatedly calling tpm_chip_start/tpm_chip_stop when
issuing commands to the tpm during initialization, just reserve the
chip after wait_startup, and release it when we are ready to call
tpm_chip_register.

Cc: Christian Bundy <christianbundy@fraction.io>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Peter Huewe <peterhuewe@gmx.de>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Stefan Berger <stefanb@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Cc: linux-integrity@vger.kernel.org
Fixes: a3fbfae ("tpm: take TPM chip power gating out of tpm_transmit()")
Fixes: 5b359c7 ("tpm_tis_core: Turn on the TPM before probing IRQ's")
Suggested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

drivers/char/tpm/tpm_tis_core.c

@@ -978,13 +978,13 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 
 	if (wait_startup(chip, 0) != 0) {
 		rc = -ENODEV;
-		goto out_err;
+		goto err_start;
 	}
 
 	/* Take control of the TPM's interrupt hardware and shut it off */
 	rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
 	if (rc < 0)
-		goto out_err;
+		goto err_start;
 
 	intmask |= TPM_INTF_CMD_READY_INT | TPM_INTF_LOCALITY_CHANGE_INT |
 		   TPM_INTF_DATA_AVAIL_INT | TPM_INTF_STS_VALID_INT;
@@ -993,21 +993,21 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 
 	rc = tpm_chip_start(chip);
 	if (rc)
-		goto out_err;
+		goto err_start;
+
 	rc = tpm2_probe(chip);
-	tpm_chip_stop(chip);
 	if (rc)
-		goto out_err;
+		goto err_probe;
 
 	rc = tpm_tis_read32(priv, TPM_DID_VID(0), &vendor);
 	if (rc < 0)
-		goto out_err;
+		goto err_probe;
 
 	priv->manufacturer_id = vendor;
 
 	rc = tpm_tis_read8(priv, TPM_RID(0), &rid);
 	if (rc < 0)
-		goto out_err;
+		goto err_probe;
 
 	dev_info(dev, "%s TPM (device-id 0x%X, rev-id %d)\n",
 		 (chip->flags & TPM_CHIP_FLAG_TPM2) ? "2.0" : "1.2",
@@ -1016,13 +1016,13 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 	probe = probe_itpm(chip);
 	if (probe < 0) {
 		rc = -ENODEV;
-		goto out_err;
+		goto err_probe;
 	}
 
 	/* Figure out the capabilities */
 	rc = tpm_tis_read32(priv, TPM_INTF_CAPS(priv->locality), &intfcaps);
 	if (rc < 0)
-		goto out_err;
+		goto err_probe;
 
 	dev_dbg(dev, "TPM interface capabilities (0x%x):\n",
 		intfcaps);
@@ -1056,10 +1056,9 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 		if (tpm_get_timeouts(chip)) {
 			dev_err(dev, "Could not get TPM timeouts and durations\n");
 			rc = -ENODEV;
-			goto out_err;
+			goto err_probe;
 		}
 
-		tpm_chip_start(chip);
 		chip->flags |= TPM_CHIP_FLAG_IRQ;
 		if (irq) {
 			tpm_tis_probe_irq_single(chip, intmask, IRQF_SHARED,
@@ -1070,18 +1069,20 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 		} else {
 			tpm_tis_probe_irq(chip, intmask);
 		}
-		tpm_chip_stop(chip);
 	}
 
+	tpm_chip_stop(chip);
+
 	rc = tpm_chip_register(chip);
 	if (rc)
-		goto out_err;
-
-	if (chip->ops->clk_enable != NULL)
-		chip->ops->clk_enable(chip, false);
+		goto err_start;
 
 	return 0;
-out_err:
+
+err_probe:
+	tpm_chip_stop(chip);
+
+err_start:
 	if ((chip->ops != NULL) && (chip->ops->clk_enable != NULL))
 		chip->ops->clk_enable(chip, false);