[PATCH AUTOSEL 5.4 277/350] tpm: Add a flag to indicate TPM power is managed by firmware

Sasha Levin
2019-12-10T21:18:38Z

From: Stephen Boyd <swboyd@chromium.org>

[ Upstream commit 2e2ee5a2db06c4b81315514b01d06fe5644342e9 ]

On some platforms, the TPM power is managed by firmware and therefore we
don't need to stop the TPM on suspend when going to a light version of
suspend such as S0ix ("freeze" suspend state). Add a chip flag,
TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED, to indicate this so that certain
platforms can probe for the usage of this light suspend and avoid
touching the TPM state across suspend/resume.

Cc: Andrey Pronin <apronin@chromium.org>
Cc: Duncan Laurie <dlaurie@chromium.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Alexander Steffen <Alexander.Steffen@infineon.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/char/tpm/tpm-interface.c | 8 +++++++-
drivers/char/tpm/tpm.h | 1 +
2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index d7a3888ad80f0..7f105490604c8 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -23,6 +23,7 @@
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
+#include <linux/suspend.h>
#include <linux/freezer.h>
#include <linux/tpm_eventlog.h>

@@ -394,7 +395,11 @@ int tpm_pm_suspend(struct device *dev)
return -ENODEV;

if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED)
- return 0;
+ goto suspended;
+
+ if ((chip->flags & TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED) &&
+ !pm_suspend_via_firmware())
+ goto suspended;

if (!tpm_chip_start(chip)) {
if (chip->flags & TPM_CHIP_FLAG_TPM2)
@@ -405,6 +410,7 @@ int tpm_pm_suspend(struct device *dev)
tpm_chip_stop(chip);
}

+suspended:
return rc;
}
EXPORT_SYMBOL_GPL(tpm_pm_suspend);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index a7fea3e0ca86a..f3bf2f7f755c8 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -162,6 +162,7 @@ enum tpm_chip_flags {
TPM_CHIP_FLAG_VIRTUAL = BIT(3),
TPM_CHIP_FLAG_HAVE_TIMEOUTS = BIT(4),
TPM_CHIP_FLAG_ALWAYS_POWERED = BIT(5),
+ TPM_CHIP_FLAG_FIRMWARE_POWER_MANAGED = BIT(6),
};

#define to_tpm_chip(d) container_of(d, struct tpm_chip, dev)
--
2.20.1