[PATCH 1/2] tpm, tpm_tis: Decorate tpm_get_timeouts() with request_locality()

[Jarkko Sakkinen <jarkko@kernel.org>]

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 fix
=======

Decorate tpm_get_timeouts() with request_locality() and release_locality().

Fixes: a3fbfae82b4c ("tpm: take TPM chip power gating out of tpm_transmit()")
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Laurent Bigonville <bigon@debian.org>
Cc: stable@vger.kernel.org
Reported-by: Lukasz Majczak <lma@semihalf.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
 drivers/char/tpm/tpm_tis_core.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 431919d5f48a..30843954aa36 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -1019,11 +1019,21 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq,
 	init_waitqueue_head(&priv->read_queue);
 	init_waitqueue_head(&priv->int_queue);
 	if (irq != -1) {
-		/* Before doing irq testing issue a command to the TPM in polling mode
+		/*
+		 * Before doing irq testing issue a command to the TPM in polling mode
 		 * to make sure it works. May as well use that command to set the
 		 * proper timeouts for the driver.
 		 */
-		if (tpm_get_timeouts(chip)) {
+
+		rc = request_locality(chip, 0);
+		if (rc < 0)
+			goto out_err;
+
+		rc = tpm_get_timeouts(chip);
+
+		release_locality(chip, 0);
+
+		if (rc) {
 			dev_err(dev, "Could not get TPM timeouts and durations\n");
 			rc = -ENODEV;
 			goto out_err;
-- 
2.30.1