Jarkko, all,

On Fri, Oct 16, 2015 at 09:40:23PM +0300, Jarkko Sakkinen wrote:
> Moved PPI attributes to the character device directory. This aligns with
> the sysfs guidelines and makes them race free because they are created
> atomically with the character device as part of device_register().The
> character device and the sysfs attributes appear at the same time to the
> user space.
> 
> As part of this change we enable PPI attributes also for TPM 2.0
> devices. In order to retain backwards compatibility with TPM 1.x
> devices, a symlink is created to the platform device directory.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
> Reviewed-by: Jason Gunthorpe <jason.guntho...@obsidianresearch.com>
> Tested-by: Mimi Zohar <zo...@linux.vnet.ibm.com> (on TPM 1.2)
> Tested-by: Chris J Arges <chris.j.ar...@canonical.com>
> Tested-by: Colin Ian King <colin.k...@canonical.com>
> ---
>  drivers/char/tpm/tpm-chip.c | 24 ++++++++++++++++--------
>  drivers/char/tpm/tpm.h      | 17 ++++++-----------
>  drivers/char/tpm/tpm_ppi.c  | 34 +++++++++++-----------------------
>  3 files changed, 33 insertions(+), 42 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 1082d4b..f26b0ae 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -119,6 +119,9 @@ struct tpm_chip *tpmm_chip_alloc(struct device *dev,
>       chip->dev.class = tpm_class;
>       chip->dev.release = tpm_dev_release;
>       chip->dev.parent = chip->pdev;
> +#ifdef CONFIG_ACPI
> +     chip->dev.groups = chip->groups;
> +#endif
>  
>       if (chip->dev_num == 0)
>               chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
> @@ -182,12 +185,6 @@ static int tpm1_chip_register(struct tpm_chip *chip)
>       if (rc)
>               return rc;
>  
> -     rc = tpm_add_ppi(chip);
> -     if (rc) {
> -             tpm_sysfs_del_device(chip);
> -             return rc;
> -     }
> -
>       chip->bios_dir = tpm_bios_log_setup(chip->devname);
>  
>       return 0;
> @@ -201,8 +198,6 @@ static void tpm1_chip_unregister(struct tpm_chip *chip)
>       if (chip->bios_dir)
>               tpm_bios_log_teardown(chip->bios_dir);
>  
> -     tpm_remove_ppi(chip);
> -
>       tpm_sysfs_del_device(chip);
>  }
>  
> @@ -225,10 +220,20 @@ int tpm_chip_register(struct tpm_chip *chip)
>       if (rc)
>               return rc;
>  
> +     tpm_add_ppi(chip);
> +
>       rc = tpm_dev_add_device(chip);
>       if (rc)
>               goto out_err;
>  
> +     if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
> +             rc = __compat_only_sysfs_link_entry_to_kobj(&chip->pdev->kobj,
> +                                                         &chip->dev.kobj,
> +                                                         "ppi");
> +             if (rc)
> +                     goto out_err;
> +     }
> +
>       /* Make the chip available. */
>       spin_lock(&driver_lock);
>       list_add_rcu(&chip->list, &tpm_chip_list);
> @@ -263,6 +268,9 @@ void tpm_chip_unregister(struct tpm_chip *chip)
>       spin_unlock(&driver_lock);
>       synchronize_rcu();
>  
> +     if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
> +             sysfs_remove_link(&chip->pdev->kobj, "ppi");
> +
>       tpm1_chip_unregister(chip);
>       tpm_dev_del_device(chip);
>  }
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 39be5ac..36ceb71 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -158,8 +158,7 @@ struct tpm_vendor_specific {
>  
>  enum tpm_chip_flags {
>       TPM_CHIP_FLAG_REGISTERED        = BIT(0),
> -     TPM_CHIP_FLAG_PPI               = BIT(1),
> -     TPM_CHIP_FLAG_TPM2              = BIT(2),
> +     TPM_CHIP_FLAG_TPM2              = BIT(1),
>  };
>  
>  struct tpm_chip {
> @@ -182,6 +181,8 @@ struct tpm_chip {
>       struct dentry **bios_dir;
>  
>  #ifdef CONFIG_ACPI
> +     const struct attribute_group *groups[2];
> +     unsigned int groups_cnt;
>       acpi_handle acpi_dev_handle;
>       char ppi_version[TPM_PPI_VERSION_LEN + 1];
>  #endif /* CONFIG_ACPI */
> @@ -189,7 +190,7 @@ struct tpm_chip {
>       struct list_head list;
>  };
>  
> -#define to_tpm_chip(n) container_of(n, struct tpm_chip, vendor)
> +#define to_tpm_chip(d) container_of(d, struct tpm_chip, dev)
>  
>  static inline void tpm_chip_put(struct tpm_chip *chip)
>  {
> @@ -419,15 +420,9 @@ void tpm_sysfs_del_device(struct tpm_chip *chip);
>  int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
>  
>  #ifdef CONFIG_ACPI
> -extern int tpm_add_ppi(struct tpm_chip *chip);
> -extern void tpm_remove_ppi(struct tpm_chip *chip);
> +extern void tpm_add_ppi(struct tpm_chip *chip);
>  #else
> -static inline int tpm_add_ppi(struct tpm_chip *chip)
> -{
> -     return 0;
> -}
> -
> -static inline void tpm_remove_ppi(struct tpm_chip *chip)
> +static inline void tpm_add_ppi(struct tpm_chip *chip)
>  {
>  }
>  #endif
> diff --git a/drivers/char/tpm/tpm_ppi.c b/drivers/char/tpm/tpm_ppi.c
> index 6ca9b5d..692a2c6 100644
> --- a/drivers/char/tpm/tpm_ppi.c
> +++ b/drivers/char/tpm/tpm_ppi.c
> @@ -53,7 +53,7 @@ tpm_eval_dsm(acpi_handle ppi_handle, int func, 
> acpi_object_type type,
>  static ssize_t tpm_show_ppi_version(struct device *dev,
>                                   struct device_attribute *attr, char *buf)
>  {
> -     struct tpm_chip *chip = dev_get_drvdata(dev);
> +     struct tpm_chip *chip = to_tpm_chip(dev);
>  
>       return scnprintf(buf, PAGE_SIZE, "%s\n", chip->ppi_version);
>  }
> @@ -63,7 +63,7 @@ static ssize_t tpm_show_ppi_request(struct device *dev,
>  {
>       ssize_t size = -EINVAL;
>       union acpi_object *obj;
> -     struct tpm_chip *chip = dev_get_drvdata(dev);
> +     struct tpm_chip *chip = to_tpm_chip(dev);
>  
>       obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETREQ,
>                          ACPI_TYPE_PACKAGE, NULL);
> @@ -100,7 +100,7 @@ static ssize_t tpm_store_ppi_request(struct device *dev,
>       int func = TPM_PPI_FN_SUBREQ;
>       union acpi_object *obj, tmp;
>       union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(1, &tmp);
> -     struct tpm_chip *chip = dev_get_drvdata(dev);
> +     struct tpm_chip *chip = to_tpm_chip(dev);
>  
>       /*
>        * the function to submit TPM operation request to pre-os environment
> @@ -156,7 +156,7 @@ static ssize_t tpm_show_ppi_transition_action(struct 
> device *dev,
>               .buffer.length = 0,
>               .buffer.pointer = NULL
>       };
> -     struct tpm_chip *chip = dev_get_drvdata(dev);
> +     struct tpm_chip *chip = to_tpm_chip(dev);
>  
>       static char *info[] = {
>               "None",
> @@ -197,7 +197,7 @@ static ssize_t tpm_show_ppi_response(struct device *dev,
>       acpi_status status = -EINVAL;
>       union acpi_object *obj, *ret_obj;
>       u64 req, res;
> -     struct tpm_chip *chip = dev_get_drvdata(dev);
> +     struct tpm_chip *chip = to_tpm_chip(dev);
>  
>       obj = tpm_eval_dsm(chip->acpi_dev_handle, TPM_PPI_FN_GETRSP,
>                          ACPI_TYPE_PACKAGE, NULL);
> @@ -296,7 +296,7 @@ static ssize_t tpm_show_ppi_tcg_operations(struct device 
> *dev,
>                                          struct device_attribute *attr,
>                                          char *buf)
>  {
> -     struct tpm_chip *chip = dev_get_drvdata(dev);
> +     struct tpm_chip *chip = to_tpm_chip(dev);
>  
>       return show_ppi_operations(chip->acpi_dev_handle, buf, 0,
>                                  PPI_TPM_REQ_MAX);
> @@ -306,7 +306,7 @@ static ssize_t tpm_show_ppi_vs_operations(struct device 
> *dev,
>                                         struct device_attribute *attr,
>                                         char *buf)
>  {
> -     struct tpm_chip *chip = dev_get_drvdata(dev);
> +     struct tpm_chip *chip = to_tpm_chip(dev);
>  
>       return show_ppi_operations(chip->acpi_dev_handle, buf, PPI_VS_REQ_START,
>                                  PPI_VS_REQ_END);
> @@ -334,17 +334,16 @@ static struct attribute_group ppi_attr_grp = {
>       .attrs = ppi_attrs
>  };
>  
> -int tpm_add_ppi(struct tpm_chip *chip)
> +void tpm_add_ppi(struct tpm_chip *chip)
>  {
>       union acpi_object *obj;
> -     int rc;
>  
>       if (!chip->acpi_dev_handle)
> -             return 0;
> +             return;
>  
>       if (!acpi_check_dsm(chip->acpi_dev_handle, tpm_ppi_uuid,
>                           TPM_PPI_REVISION_ID, 1 << TPM_PPI_FN_VERSION))
> -             return 0;
> +             return;
>  
>       /* Cache PPI version string. */
>       obj = acpi_evaluate_dsm_typed(chip->acpi_dev_handle, tpm_ppi_uuid,
> @@ -356,16 +355,5 @@ int tpm_add_ppi(struct tpm_chip *chip)
>               ACPI_FREE(obj);
>       }
>  
> -     rc = sysfs_create_group(&chip->pdev->kobj, &ppi_attr_grp);
> -
> -     if (!rc)
> -             chip->flags |= TPM_CHIP_FLAG_PPI;
> -
> -     return rc;
> -}
> -
> -void tpm_remove_ppi(struct tpm_chip *chip)
> -{
> -     if (chip->flags & TPM_CHIP_FLAG_PPI)
> -             sysfs_remove_group(&chip->pdev->kobj, &ppi_attr_grp);
> +     chip->groups[chip->groups_cnt++] = &ppi_attr_grp;
>  }
> -- 
> 2.5.0
> 
> --
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The commit for this patch (9b774d5cf2db4) present in the latest
linux-next (20151101+) breaks suspend/resume on an Acer C720 Chromebook.
The computer will successfully suspend but when a resume is attempted
a blank screen is displayed for a few seconds and then it reboots.

-- 
- Jeremiah Mahler
--
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