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path: root/drivers/char/tpm/tpm-chip.c
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Diffstat (limited to 'drivers/char/tpm/tpm-chip.c')
-rw-r--r--drivers/char/tpm/tpm-chip.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 322b8a51ffc6..67ec9d3d04f5 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -143,6 +143,39 @@ static void tpm_devs_release(struct device *dev)
}
/**
+ * tpm_class_shutdown() - prepare the TPM device for loss of power.
+ * @dev: device to which the chip is associated.
+ *
+ * Issues a TPM2_Shutdown command prior to loss of power, as required by the
+ * TPM 2.0 spec.
+ * Then, calls bus- and device- specific shutdown code.
+ *
+ * XXX: This codepath relies on the fact that sysfs is not enabled for
+ * TPM2: sysfs uses an implicit lock on chip->ops, so this could race if TPM2
+ * has sysfs support enabled before TPM sysfs's implicit locking is fixed.
+ */
+static int tpm_class_shutdown(struct device *dev)
+{
+ struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
+
+ if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+ down_write(&chip->ops_sem);
+ tpm2_shutdown(chip, TPM2_SU_CLEAR);
+ chip->ops = NULL;
+ up_write(&chip->ops_sem);
+ }
+ /* Allow bus- and device-specific code to run. Note: since chip->ops
+ * is NULL, more-specific shutdown code will not be able to issue TPM
+ * commands.
+ */
+ if (dev->bus && dev->bus->shutdown)
+ dev->bus->shutdown(dev);
+ else if (dev->driver && dev->driver->shutdown)
+ dev->driver->shutdown(dev);
+ return 0;
+}
+
+/**
* tpm_chip_alloc() - allocate a new struct tpm_chip instance
* @pdev: device to which the chip is associated
* At this point pdev mst be initialized, but does not have to
@@ -181,6 +214,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
device_initialize(&chip->devs);
chip->dev.class = tpm_class;
+ chip->dev.class->shutdown = tpm_class_shutdown;
chip->dev.release = tpm_dev_release;
chip->dev.parent = pdev;
chip->dev.groups = chip->groups;