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Message-ID: <1489382517-9078-1-git-send-email-Meng.Li@windriver.com>
Date: Mon, 13 Mar 2017 13:21:57 +0800
From: <Meng.Li@...driver.com>
To: <linux-kernel@...r.kernel.org>
CC: <peterhuewe@....de>, <tpmdd@...horst.net>,
<jarkko.sakkinen@...ux.intel.com>,
<jgunthorpe@...idianresearch.com>,
<tpmdd-devel@...ts.sourceforge.net>
Subject: [PATCH] tpm: Add sysfs interface to show TPM hardware version
From: Limeng <Meng.Li@...driver.com>
So far, there is not a sysfs interface for user space code to
check the TPM hardware version(TPM1.x or TPM2). So, add a
file named description in /sys/class/tpm/tpmX/ to show it.
Signed-off-by: Meng Li <Meng.Li@...driver.com>
---
drivers/char/tpm/tpm-chip.c | 85 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 85 insertions(+)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index c406343..da2cd69 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -36,6 +36,83 @@
dev_t tpm_devt;
/**
+ * show_description - sysfs interface for checking current TPM hardware version.
+ * @dev: pointer to tpm chip device
+ * @attr: unused
+ * @buf: char buffer to be filled with TPM hardware version info
+ *
+ * Provides sysfs interface for showing current TPM hardware version.
+ */
+static ssize_t show_description(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct tpm_chip *chip = (struct tpm_chip *)container_of(dev,struct tpm_chip,dev);
+ int ret;
+
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ ret = sprintf(buf, "TPM 2.0");
+ else
+ ret = sprintf(buf, "TPM 1.x");
+
+ return ret;
+}
+
+/**
+ * store_description - interface for manually setting data.
+ * @dev: unused
+ * @attr: unused
+ * @buf: unused
+ * @count: unused
+ *
+ * There is not any process in this function, reserve for feature.
+ */
+static ssize_t store_description(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ return count;
+}
+
+static struct device_attribute tpm_attrs[] = {
+ __ATTR(description, S_IRUGO | S_IWUSR, show_description, store_description),
+};
+
+/**
+ * tpm_create_sysfs - Create tpm sysfs interface.
+ * @dev: pointer to tpm chip device
+ *
+ * Create sysfs interface for checking current TPM hardware version.
+ */
+static int tpm_create_sysfs(struct device *dev)
+{
+ int r, t;
+
+ for (t = 0; t < ARRAY_SIZE(tpm_attrs); t++) {
+ r = device_create_file(dev, &tpm_attrs[t]);
+ if (r) {
+ dev_err(dev, "failed to create sysfs file\n");
+ return r;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * tpm_remove_sysfs - Remove tpm sysfs interface.
+ * @dev: pointer to tpm chip device
+ *
+ * Remove sysfs interface for checking current TPM hardware version.
+ */
+static void tpm_remove_sysfs(struct device *dev)
+{
+ int t;
+
+ for (t = 0; t < ARRAY_SIZE(tpm_attrs); t++) {
+ device_remove_file(dev, &tpm_attrs[t]);
+ }
+}
+
+/**
* tpm_try_get_ops() - Get a ref to the tpm_chip
* @chip: Chip to ref
*
@@ -363,6 +440,13 @@ int tpm_chip_register(struct tpm_chip *chip)
return rc;
}
+ rc = tpm_create_sysfs(&chip->dev);
+ if (rc) {
+ tpm_del_legacy_sysfs(chip);
+ tpm_chip_unregister(chip);
+ return rc;
+ }
+
return 0;
}
EXPORT_SYMBOL_GPL(tpm_chip_register);
@@ -382,6 +466,7 @@ int tpm_chip_register(struct tpm_chip *chip)
*/
void tpm_chip_unregister(struct tpm_chip *chip)
{
+ tpm_remove_sysfs(&chip->dev);
tpm_del_legacy_sysfs(chip);
tpm_bios_log_teardown(chip);
tpm_del_char_device(chip);
--
1.7.9.5
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