[PATCH v9 17/19] tpm: Add sysfs interface to allow setting and querying the preferred locality

[Ross Philipson]

Expose a sysfs interface to allow user mode to set and query the preferred
locality for the TPM chip.

Signed-off-by: Ross Philipson <ross.philipson at oracle.com>
---
 drivers/char/tpm/tpm-sysfs.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 94231f052ea7..5f4a966a4599 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -324,6 +324,34 @@ static ssize_t null_name_show(struct device *dev, struct device_attribute *attr,
 static DEVICE_ATTR_RO(null_name);
 #endif
 
+static ssize_t preferred_locality_show(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	struct tpm_chip *chip = to_tpm_chip(dev);
+
+	return sprintf(buf, "%d\n", chip->pref_locality);
+}
+
+static ssize_t preferred_locality_store(struct device *dev, struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct tpm_chip *chip = to_tpm_chip(dev);
+	unsigned int locality;
+
+	if (kstrtouint(buf, 0, &locality))
+		return -ERANGE;
+
+	if (locality >= TPM_MAX_LOCALITY)
+		return -ERANGE;
+
+	if (tpm_chip_preferred_locality(chip, (int)locality))
+		return count;
+	else
+		return 0;
+}
+
+static DEVICE_ATTR_RW(preferred_locality);
+
 static struct attribute *tpm1_dev_attrs[] = {
 	&dev_attr_pubek.attr,
 	&dev_attr_pcrs.attr,
@@ -336,6 +364,7 @@ static struct attribute *tpm1_dev_attrs[] = {
 	&dev_attr_durations.attr,
 	&dev_attr_timeouts.attr,
 	&dev_attr_tpm_version_major.attr,
+	&dev_attr_preferred_locality.attr,
 	NULL,
 };
 
@@ -344,6 +373,7 @@ static struct attribute *tpm2_dev_attrs[] = {
 #ifdef CONFIG_TCG_TPM2_HMAC
 	&dev_attr_null_name.attr,
 #endif
+	&dev_attr_preferred_locality.attr,
 	NULL
 };
 
-- 
2.39.3