linux-kernel - [PATCH v2 1/2] tpm: do not suspend/resume if power stays on

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Message-Id: <20180530204440.27299-2-jarkko.sakkinen@linux.intel.com>
Date:   Wed, 30 May 2018 23:44:39 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     stable@...r.kernel.org
Cc:     Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Sonny Rao <sonnyrao@...omium.org>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        James Morris <james.l.morris@...cle.com>,
        Peter Huewe <peterhuewe@....de>,
        Marcel Selhorst <tpmdd@...horst.net>,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        tpmdd-devel@...ts.sourceforge.net (moderated list:TPM DEVICE DRIVER),
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v2 1/2] tpm: do not suspend/resume if power stays on

From: Enric Balletbo i Serra <enric.balletbo@...labora.com>

commit b5d0ebc99bf5d0801a5ecbe958caa3d68b8eaee8 upstream

The suspend/resume behavior of the TPM can be controlled by setting
"powered-while-suspended" in the DTS. This is useful for the cases
when hardware does not power-off the TPM.

Signed-off-by: Sonny Rao <sonnyrao@...omium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@...idianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Signed-off-by: James Morris <james.l.morris@...cle.com>
---
 drivers/char/tpm/tpm-chip.c      | 12 ++++++++++++
 drivers/char/tpm/tpm-interface.c |  3 +++
 drivers/char/tpm/tpm.h           |  1 +
 3 files changed, 16 insertions(+)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index a0d9ac6b6cc9..a8d7220f613c 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -324,8 +324,20 @@ static void tpm1_chip_unregister(struct tpm_chip *chip)
  */
 int tpm_chip_register(struct tpm_chip *chip)
 {
+#ifdef CONFIG_TCG_IBMVTPM
+	struct device_node *np;
+#endif
 	int rc;
 
+#ifdef CONFIG_TCG_IBMVTPM
+	np = of_find_node_by_name(NULL, "vtpm");
+	if (!np)
+		return -ENODEV;
+	if (of_property_read_bool(np, "powered-while-suspended"))
+		chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
+	of_node_put(np);
+#endif
+
 	rc = tpm1_chip_register(chip);
 	if (rc)
 		return rc;
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index aaa5fa95dede..247dd2b6504a 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -931,6 +931,9 @@ int tpm_pm_suspend(struct device *dev)
 	if (chip == NULL)
 		return -ENODEV;
 
+	if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
+		return 0;
+
 	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
 		tpm2_shutdown(chip, TPM2_SU_STATE);
 		return 0;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 772d99b3a8e4..36e1abda00f9 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -168,6 +168,7 @@ struct tpm_vendor_specific {
 enum tpm_chip_flags {
 	TPM_CHIP_FLAG_REGISTERED	= BIT(0),
 	TPM_CHIP_FLAG_TPM2		= BIT(1),
+	TPM_CHIP_FLAG_ALWAYS_POWERED	= BIT(5),
 };
 
 struct tpm_chip {
-- 
2.17.0