tpm: Add a flag to indicate TPM power is managed by firmware

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>

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index d7a3888ad80f0a60b88f0193ada481c304e70e08..7f105490604c836263cf86bea05b2a6e5ea37574 100644 (file)
--- 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 a4f74dd02a3541cd196e9b1531dbfd15cbeb4449..80bca88b1f9196e9f4dacc19462b8bbd4d869767 100644 (file)
--- 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)