linux-kernel - [PATCH v4 5/6] tpm, tpm_tis: Move irq test from tpm_tis_send() to tpm_tis_probe_irq

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Message-Id: <20220509080559.4381-6-LinoSanfilippo@gmx.de>
Date:   Mon,  9 May 2022 10:05:58 +0200
From:   Lino Sanfilippo <LinoSanfilippo@....de>
To:     peterhuewe@....de, jarkko@...nel.org, jgg@...pe.ca
Cc:     stefanb@...ux.vnet.ibm.com, linux@...ewoehner.de,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        LinoSanfilippo@....de, lukas@...ner.de, p.rosenberger@...bus.com,
        Lino Sanfilippo <l.sanfilippo@...bus.com>
Subject: [PATCH v4 5/6] tpm, tpm_tis: Move irq test from tpm_tis_send() to tpm_tis_probe_irq_single()

From: Lino Sanfilippo <l.sanfilippo@...bus.com>

There is no need to check for the irq test completion at each data
transmission during the driver livetime. Instead do the check only once at
driver startup.

Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
---
 drivers/char/tpm/tpm_tis_core.c | 68 +++++++++++----------------------
 1 file changed, 22 insertions(+), 46 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index bdfde1cd71fe..4c65718feb7d 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -432,7 +432,7 @@ static void disable_interrupts(struct tpm_chip *chip)
  * tpm.c can skip polling for the data to be available as the interrupt is
  * waited for here
  */
-static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
+static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 	int rc;
@@ -465,30 +465,6 @@ static int tpm_tis_send_main(struct tpm_chip *chip, const u8 *buf, size_t len)
 	return rc;
 }
 
-static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
-{
-	int rc, irq;
-	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-
-	if (!(chip->flags & TPM_CHIP_FLAG_IRQ) ||
-	     test_bit(TPM_TIS_IRQTEST_OK, &priv->irqtest_flags))
-		return tpm_tis_send_main(chip, buf, len);
-
-	/* Verify receipt of the expected IRQ */
-	irq = priv->irq;
-	priv->irq = 0;
-	chip->flags &= ~TPM_CHIP_FLAG_IRQ;
-	rc = tpm_tis_send_main(chip, buf, len);
-	priv->irq = irq;
-	chip->flags |= TPM_CHIP_FLAG_IRQ;
-	if (!test_bit(TPM_TIS_IRQTEST_OK, &priv->irqtest_flags))
-		tpm_msleep(1);
-	if (!test_bit(TPM_TIS_IRQTEST_OK, &priv->irqtest_flags))
-		disable_interrupts(chip);
-	set_bit(TPM_TIS_IRQTEST_OK, &priv->irqtest_flags);
-	return rc;
-}
-
 struct tis_vendor_durations_override {
 	u32 did_vid;
 	struct tpm1_version version;
@@ -759,51 +735,54 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
 
 	rc = tpm_tis_read8(priv, TPM_INT_VECTOR(priv->locality),
 			   &original_int_vec);
-	if (rc < 0)
+	if (rc < 0) {
+		disable_interrupts(chip);
 		return rc;
+	}
 
 	rc = tpm_tis_write8(priv, TPM_INT_VECTOR(priv->locality), irq);
 	if (rc < 0)
-		return rc;
+		goto out_err;
 
 	rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &int_status);
 	if (rc < 0)
-		return rc;
+		goto out_err;
 
 	/* Clear all existing */
 	rc = tpm_tis_write32(priv, TPM_INT_STATUS(priv->locality), int_status);
 	if (rc < 0)
-		return rc;
+		goto out_err;
 
 	/* Turn on */
 	rc = tpm_tis_write32(priv, TPM_INT_ENABLE(priv->locality),
 			     intmask | TPM_GLOBAL_INT_ENABLE);
 	if (rc < 0)
-		return rc;
+		goto out_err;
 
 	clear_bit(TPM_TIS_IRQTEST_OK, &priv->irqtest_flags);
-	chip->flags |= TPM_CHIP_FLAG_IRQ;
 
 	/* Generate an interrupt by having the core call through to
 	 * tpm_tis_send
 	 */
 	rc = tpm_tis_gen_interrupt(chip);
 	if (rc < 0)
-		return rc;
+		goto out_err;
 
-	/* tpm_tis_send will either confirm the interrupt is working or it
-	 * will call disable_irq which undoes all of the above.
-	 */
-	if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) {
-		rc = tpm_tis_write8(priv, original_int_vec,
-				TPM_INT_VECTOR(priv->locality));
-		if (rc < 0)
-			return rc;
+	tpm_msleep(1);
 
-		return 1;
-	}
+	/* Verify receipt of the expected IRQ */
+	if (!test_bit(TPM_TIS_IRQTEST_OK, &priv->irqtest_flags))
+		goto out_err;
+
+	chip->flags |= TPM_CHIP_FLAG_IRQ;
 
 	return 0;
+
+out_err:
+	disable_interrupts(chip);
+	tpm_tis_write8(priv, original_int_vec, TPM_INT_VECTOR(priv->locality));
+
+	return rc;
 }
 
 /* Try to find the IRQ the TPM is using. This is for legacy x86 systems that
@@ -1075,12 +1054,9 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 		if (irq) {
 			tpm_tis_probe_irq_single(chip, intmask, IRQF_SHARED,
 						 irq);
-			if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) {
+			if (!(chip->flags & TPM_CHIP_FLAG_IRQ))
 				dev_err(&chip->dev, FW_BUG
 					"TPM interrupt not working, polling instead\n");
-
-				disable_interrupts(chip);
-			}
 		} else {
 			tpm_tis_probe_irq(chip, intmask);
 		}
-- 
2.36.0