On Mon, Mar 13, 2017 at 01:21:57PM +0800, meng...@windriver.com wrote:
> From: Limeng <meng...@windriver.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...@windriver.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
tpm-sysfs.c Probably makes sense to rename legacy group there as tpm1_
> @@ -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)
family
> +{
> + 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;
> +}
What is this??
> +
> +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
You should put the attributes to chip->groups instead of racy creation
of them.
/Jarkko
