[PATCH 4.9 01/31] tpm: do not suspend/resume if power stays on

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Enric Balletbo i Serra <enric.balle...@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 <sonny...@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
Reviewed-by: Jason Gunthorpe <jguntho...@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
Signed-off-by: James Morris <james.l.mor...@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gre...@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"
 
@@ -388,8 +389,20 @@ static int tpm_add_legacy_sysfs(struct t
  */
 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
+
        if (chip->ops->flags & TPM_OPS_AUTO_STARTUP) {
                if (chip->flags & TPM_CHIP_FLAG_TPM2)
                        rc = tpm2_auto_startup(chip);
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -969,6 +969,9 @@ 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
@@ -143,6 +143,7 @@ enum tpm_chip_flags {
        TPM_CHIP_FLAG_TPM2              = BIT(1),
        TPM_CHIP_FLAG_IRQ               = BIT(2),
        TPM_CHIP_FLAG_VIRTUAL           = BIT(3),
+       TPM_CHIP_FLAG_ALWAYS_POWERED    = BIT(5),
 };
 
 struct tpm_chip {