linux-kernel - [PATCH] tpm_tis: use default timeout value if chip reports it as zero

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Message-ID: <d5469294-34e6-2e5e-43e8-9ff82579fc2a@maciej.szmigiero.name>
Date:   Fri, 13 Jan 2017 22:37:00 +0100
From:   "Maciej S. Szmigiero" <mail@...iej.szmigiero.name>
To:     tpmdd-devel@...ts.sourceforge.net
Cc:     linux-kernel <linux-kernel@...r.kernel.org>,
        Peter Huewe <peterhuewe@....de>,
        Marcel Selhorst <tpmdd@...horst.net>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Christophe Ricard <christophe.ricard@...il.com>,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Subject: [PATCH] tpm_tis: use default timeout value if chip reports it as zero

Since commit 1107d065fdf1 ("tpm_tis: Introduce intermediate layer for TPM
access") Atmel 3203 TPM on ThinkPad X61S (TPM firmware version 13.9) no
longer works.
The initialization proceeds fine until we get and start using chip-reported
timeouts - and the chip reports C and D timeouts of zero.

It turns out that until commit 8e54caf407b98e ("tpm: Provide a generic
means to override the chip returned timeouts") we had actually let default
timeout values remain in this case, so let's bring back this behavior to
make chips like Atmel 3203 work again.

Use a common code that was introduced by that commit so a warning is
printed in this case and /sys/class/tpm/tpm*/timeouts correctly says the
timeouts aren't chip-original.

Signed-off-by: Maciej S. Szmigiero <mail@...iej.szmigiero.name>

Fixes: 1107d065fdf1 ("tpm_tis: Introduce intermediate layer for TPM access")
Cc: stable@...r.kernel.org
---
This replaces "tpm_tis: override reported C and D timeouts for Atmel 3203"
submission.

 drivers/char/tpm/tpm-interface.c | 53 ++++++++++++++++++++++++----------------
 1 file changed, 32 insertions(+), 21 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index fecdd3fa8126..a3461cbdde5f 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -522,8 +522,7 @@ static int tpm_startup(struct tpm_chip *chip, __be16 startup_type)
 int tpm_get_timeouts(struct tpm_chip *chip)
 {
 	cap_t cap;
-	unsigned long new_timeout[4];
-	unsigned long old_timeout[4];
+	unsigned long timeout_old[4], timeout_chip[4], timeout_eff[4];
 	ssize_t rc;
 
 	if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)
@@ -564,11 +563,15 @@ int tpm_get_timeouts(struct tpm_chip *chip)
 		return rc;
 	}
 
-	old_timeout[0] = be32_to_cpu(cap.timeout.a);
-	old_timeout[1] = be32_to_cpu(cap.timeout.b);
-	old_timeout[2] = be32_to_cpu(cap.timeout.c);
-	old_timeout[3] = be32_to_cpu(cap.timeout.d);
-	memcpy(new_timeout, old_timeout, sizeof(new_timeout));
+	timeout_old[0] = jiffies_to_usecs(chip->timeout_a);
+	timeout_old[1] = jiffies_to_usecs(chip->timeout_b);
+	timeout_old[2] = jiffies_to_usecs(chip->timeout_c);
+	timeout_old[3] = jiffies_to_usecs(chip->timeout_d);
+	timeout_chip[0] = be32_to_cpu(cap.timeout.a);
+	timeout_chip[1] = be32_to_cpu(cap.timeout.b);
+	timeout_chip[2] = be32_to_cpu(cap.timeout.c);
+	timeout_chip[3] = be32_to_cpu(cap.timeout.d);
+	memcpy(timeout_eff, timeout_chip, sizeof(timeout_eff));
 
 	/*
 	 * Provide ability for vendor overrides of timeout values in case
@@ -576,16 +579,24 @@ int tpm_get_timeouts(struct tpm_chip *chip)
 	 */
 	if (chip->ops->update_timeouts != NULL)
 		chip->timeout_adjusted =
-			chip->ops->update_timeouts(chip, new_timeout);
+			chip->ops->update_timeouts(chip, timeout_eff);
 
 	if (!chip->timeout_adjusted) {
-		/* Don't overwrite default if value is 0 */
-		if (new_timeout[0] != 0 && new_timeout[0] < 1000) {
-			int i;
+		/* Restore default if chip reported 0 */
+		int i;
 
+		for (i = 0; i < ARRAY_SIZE(timeout_eff); i++) {
+			if (timeout_eff[i])
+				continue;
+
+			timeout_eff[i] = timeout_old[i];
+			chip->timeout_adjusted = true;
+		}
+
+		if (timeout_eff[0] != 0 && timeout_eff[0] < 1000) {
 			/* timeouts in msec rather usec */
-			for (i = 0; i != ARRAY_SIZE(new_timeout); i++)
-				new_timeout[i] *= 1000;
+			for (i = 0; i != ARRAY_SIZE(timeout_eff); i++)
+				timeout_eff[i] *= 1000;
 			chip->timeout_adjusted = true;
 		}
 	}
@@ -594,16 +605,16 @@ int tpm_get_timeouts(struct tpm_chip *chip)
 	if (chip->timeout_adjusted) {
 		dev_info(&chip->dev,
 			 HW_ERR "Adjusting reported timeouts: A %lu->%luus B %lu->%luus C %lu->%luus D %lu->%luus\n",
-			 old_timeout[0], new_timeout[0],
-			 old_timeout[1], new_timeout[1],
-			 old_timeout[2], new_timeout[2],
-			 old_timeout[3], new_timeout[3]);
+			 timeout_chip[0], timeout_eff[0],
+			 timeout_chip[1], timeout_eff[1],
+			 timeout_chip[2], timeout_eff[2],
+			 timeout_chip[3], timeout_eff[3]);
 	}
 
-	chip->timeout_a = usecs_to_jiffies(new_timeout[0]);
-	chip->timeout_b = usecs_to_jiffies(new_timeout[1]);
-	chip->timeout_c = usecs_to_jiffies(new_timeout[2]);
-	chip->timeout_d = usecs_to_jiffies(new_timeout[3]);
+	chip->timeout_a = usecs_to_jiffies(timeout_eff[0]);
+	chip->timeout_b = usecs_to_jiffies(timeout_eff[1]);
+	chip->timeout_c = usecs_to_jiffies(timeout_eff[2]);
+	chip->timeout_d = usecs_to_jiffies(timeout_eff[3]);
 
 	rc = tpm_getcap(chip, TPM_CAP_PROP_TIS_DURATION, &cap,
 			"attempting to determine the durations");