[PATCH] tpm, tpm_tis: Acquire locality in tpm_tis_gen_interrupt() and tpm_get_timeouts()

[Jarkko Sakkinen <jarkko@kernel.org>]

From: Lukasz Majczak <lma@semihalf.com>

This is shown with Samsung Chromebook Pro (Caroline) with TPM 1.2
(SLB 9670):

[    4.324298] TPM returned invalid status
[    4.324806] WARNING: CPU: 2 PID: 1 at drivers/char/tpm/tpm_tis_core.c:275 tpm_tis_status+0x86/0x8f

Background
==========

TCG PC Client Platform TPM Profile (PTP) Specification, paragraph 6.1 FIFO
Interface Locality Usage per Register, Table 39 Register Behavior Based on
Locality Setting for FIFO - a read attempt to TPM_STS_x Registers returns
0xFF in case of lack of locality. The described situation manifests itself
with the following warning trace:

The fix
=======

Add the proper decorations to tpm_tis_gen_interrupt() and
tpm_get_timeouts().

Cc: Laurent Bigonville <bigon@debian.org>
Fixes: a3fbfae82b4c ("tpm: take TPM chip power gating out of tpm_transmit()")
Signed-off-by: Lukasz Majczak <lma@semihalf.com>
Co-developed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
---
It was easier to write a new patch based on v5. Since v5 had a crippled
change log I just restarted the version count.
 drivers/char/tpm/tpm-interface.c | 16 ++++++++++++++--
 drivers/char/tpm/tpm_tis_core.c  | 16 +++++++++++++---
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1621ce818705..9ab155ae5726 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -238,13 +238,25 @@ EXPORT_SYMBOL_GPL(tpm_transmit_cmd);
 
 int tpm_get_timeouts(struct tpm_chip *chip)
 {
+	int ret;
+
 	if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)
 		return 0;
 
+	/* TPM 2.0 */
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		return tpm2_get_timeouts(chip);
-	else
-		return tpm1_get_timeouts(chip);
+
+
+	ret = tpm_chip_start(chip);
+	if (ret)
+		return ret;
+
+	ret = tpm1_get_timeouts(chip);
+
+	tpm_chip_stop(chip);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(tpm_get_timeouts);
 
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 431919d5f48a..ce80e7a2d420 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -707,12 +707,22 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
 	const char *desc = "attempting to generate an interrupt";
 	u32 cap2;
 	cap_t cap;
+	int ret;
 
+	/* TPM 2.0 */
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		return tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
-	else
-		return tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc,
-				  0);
+
+	/* TPM 1.2 */
+	ret = request_locality(chip, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc, 0);
+
+	release_locality(chip, 0);
+
+	return ret;
 }
 
 /* Register the IRQ and issue a command that will cause an interrupt. If an
-- 
2.30.1