From: Sonny Rao <sonnyrao@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
---
Changes since v2:
Jarkko Sakkinen
- Add a new TPM_CHIP_FLAG_ALWAYS_POWERED flag instead of using a boolean variable.
- Remove a trailing newline.
Changes since v1:
Jason Gunthorpe :
- Move the code to handle suspend/resume in the common chip code.
Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt | 6 ++++++
drivers/char/tpm/tpm-interface.c | 3 +++
drivers/char/tpm/tpm.h | 1 +
drivers/char/tpm/tpm_of.c | 3 +++
4 files changed, 13 insertions(+)
diff --git a/Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt b/Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt
index 8cb638b..85c8216 100644
--- a/Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt
+++ b/Documentation/devicetree/bindings/security/tpm/tpm-i2c.txt
@@ -8,6 +8,12 @@ Required properties:
the firmware event log
- linux,sml-size : size of the memory allocated for the firmware event log
+Optional properties:
+
+- powered-while-suspended: present when the TPM is left powered on between
+ suspend and resume (makes the suspend/resume
+ callbacks do nothing).
+
Example (for OpenPower Systems with Nuvoton TPM 2.0 on I2C)
----------------------------------------------------------
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index a2688ac..6869093 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -944,6 +944,9 @@ 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 1ae9768..0ce379c 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -146,6 +146,7 @@ enum tpm_chip_flags {
TPM_CHIP_FLAG_IRQ = BIT(2),
TPM_CHIP_FLAG_VIRTUAL = BIT(3),
TPM_CHIP_FLAG_HAVE_TIMEOUTS = BIT(4),
+ TPM_CHIP_FLAG_ALWAYS_POWERED = BIT(5),
};
struct tpm_chip_seqops {
diff --git a/drivers/char/tpm/tpm_of.c b/drivers/char/tpm/tpm_of.c
index 7dee42d7..e89276c 100644
--- a/drivers/char/tpm/tpm_of.c
+++ b/drivers/char/tpm/tpm_of.c
@@ -34,6 +34,9 @@ int tpm_read_log_of(struct tpm_chip *chip)
else
return -ENODEV;
+ if (of_property_read_bool(np, "powered-while-suspended"))
+ chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
+
sizep = of_get_property(np, "linux,sml-size", NULL);
basep = of_get_property(np, "linux,sml-base", NULL);
if (sizep == NULL && basep == NULL)
--
2.9.3
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
