Re: [PATCH v4 3/5] tpm: of: Make of-tree specific function commonly available

Jarkko Sakkinen
2022-07-11T00:01:40Z

On Thu, Jun 30, 2022 at 10:26:01PM -0400, Stefan Berger wrote:
> Simplify tpm_read_log_of() by moving reusable parts of the code into
> an inline function that makes it commonly available so it can be
> used also for kexec support. Call the new of_tpm_get_sml_parameters()
> function from the TPM Open Firmware driver.
>
> Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
> Cc: Jarkko Sakkinen <jarkko@kernel.org>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Frank Rowand <frowand.list@gmail.com>
>
> ---
> v4:
> - converted to inline function
> ---
> drivers/char/tpm/eventlog/of.c | 31 +++++--------------------------
> include/linux/tpm.h | 27 +++++++++++++++++++++++++++
> 2 files changed, 32 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
> index a9ce66d09a75..f9462d19632e 100644
> --- a/drivers/char/tpm/eventlog/of.c
> +++ b/drivers/char/tpm/eventlog/of.c
> @@ -12,6 +12,7 @@
>
> #include <linux/slab.h>
> #include <linux/of.h>
> +#include <linux/tpm.h>
> #include <linux/tpm_eventlog.h>
>
> #include "../tpm.h"
> @@ -20,11 +21,10 @@
> int tpm_read_log_of(struct tpm_chip *chip)
> {
> struct device_node *np;
> - const u32 *sizep;
> - const u64 *basep;
> struct tpm_bios_log *log;
> u32 size;
> u64 base;
> + int ret;
>
> log = &chip->log;
> if (chip->dev.parent && chip->dev.parent->of_node)
> @@ -35,30 +35,9 @@ int tpm_read_log_of(struct tpm_chip *chip)
> if (of_property_read_bool(np, "powered-while-suspended"))
> chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
>
> - sizep = of_get_property(np, "linux,sml-size", NULL);
> - basep = of_get_property(np, "linux,sml-base", NULL);
> - if (sizep == NULL && basep == NULL)
> - return -ENODEV;
> - if (sizep == NULL || basep == NULL)
> - return -EIO;
> -
> - /*
> - * For both vtpm/tpm, firmware has log addr and log size in big
> - * endian format. But in case of vtpm, there is a method called
> - * sml-handover which is run during kernel init even before
> - * device tree is setup. This sml-handover function takes care
> - * of endianness and writes to sml-base and sml-size in little
> - * endian format. For this reason, vtpm doesn't need conversion
> - * but physical tpm needs the conversion.
> - */
> - if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
> - of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
> - size = be32_to_cpup((__force __be32 *)sizep);
> - base = be64_to_cpup((__force __be64 *)basep);
> - } else {
> - size = *sizep;
> - base = *basep;
> - }
> + ret = of_tpm_get_sml_parameters(np, &base, &size);
> + if (ret < 0)
> + return ret;
>
> if (size == 0) {
> dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index dfeb25a0362d..b3dff255bc58 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -460,4 +460,31 @@ static inline struct tpm_chip *tpm_default_chip(void)
> return NULL;
> }
> #endif
> +
> +#ifdef CONFIG_OF
> +static inline int of_tpm_get_sml_parameters(struct device_node *np,
> + u64 *base, u32 *size)
> +{
> + const u32 *sizep;
> + const u64 *basep;
> +
> + sizep = of_get_property(np, "linux,sml-size", NULL);
> + basep = of_get_property(np, "linux,sml-base", NULL);
> + if (sizep == NULL && basep == NULL)
> + return -ENODEV;
> + if (sizep == NULL || basep == NULL)
> + return -EIO;
> +
> + if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
> + of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
> + *size = be32_to_cpup((__force __be32 *)sizep);
> + *base = be64_to_cpup((__force __be64 *)basep);
> + } else {
> + *size = *sizep;
> + *base = *basep;
> + }
> + return 0;
> +}
> +#endif
> +
> #endif
> --
> 2.35.1
>

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko