tpm, tpm_tis: Decorate tpm_tis_gen_interrupt() with request_locality()

From: Lukasz Majczak <[email protected]>

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_tis_gen_interrupt() with request_locality() and release_locality().

---
 drivers/char/tpm/tpm_tis_core.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

index 30843954aa36..a2e0395cbe61 100644
@@ -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