[PATCH 4.4 01/24] tpm: do not suspend/resume if power stays on

Greg Kroah-Hartman
2018-06-12T16:52:45Z

From: Enric Balletbo i Serra <enric.balletbo@collabora.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@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/char/tpm/tpm-chip.c | 13 +++++++++++++
drivers/char/tpm/tpm-interface.c | 3 +++
drivers/char/tpm/tpm.h | 1 +
3 files changed, 17 insertions(+)

--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -26,6 +26,7 @@
#include <linux/spinlock.h>
#include <linux/freezer.h>
#include <linux/major.h>
+#include <linux/of.h>
#include "tpm.h"
#include "tpm_eventlog.h"

@@ -324,8 +325,20 @@ static void tpm1_chip_unregister(struct
*/
int tpm_chip_register(struct tpm_chip *chip)
{
+#ifdef CONFIG_OF
+ struct device_node *np;
+#endif
int rc;

+#ifdef CONFIG_OF
+ np = of_find_node_by_name(NULL, "vtpm");
+ if (np) {
+ 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;
--- 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;
--- 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 {