> -----Original Message-----
> From: Jarkko Sakkinen [mailto:jarkko.sakki...@linux.intel.com]
> Sent: Monday, March 13, 2017 7:49 PM
> To: Li, Meng
> Cc: linux-ker...@vger.kernel.org; peterhu...@gmx.de;
> tp...@selhorst.net; jguntho...@obsidianresearch.com; tpmdd-
> de...@lists.sourceforge.net
> Subject: Re: [PATCH] tpm: Add sysfs interface to show TPM hardware
> version
>
> 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_
Thanks for this advice.
>
> > @@ -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.
Thanks for your advice. It is more reasonable in to chip->groups.
Regards,
Limeng
>
> /Jarkko
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