Re: [PATCH v2 1/3] tpm: of: Move of-tree specific code from tpm driver into of driver

[Rob Herring <robh@kernel.org>]

On Thu, Jun 16, 2022 at 11:41:28AM -0400, Stefan Berger wrote:
> Simplify tpm_read_log_of() by moving Openfirmware-specific code into
> the Openfirmware driver to make the code reusable. Call the new

There is no such 'Openfirmware driver'.

> of_tpm_get_sml_parameters() function from the TPM Openfirmware 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>
> ---
>  drivers/char/tpm/eventlog/of.c | 31 +++++--------------------------
>  drivers/of/Makefile            |  2 +-
>  drivers/of/device_node.c       | 27 +++++++++++++++++++++++++++

Humm, definitely the wrong direction. Generally, code for specific 
bindings does not go in drivers/of/. There used to be some, but we've 
moved it to the appropriate subsystems. kexec was an exception to not 
have 2 copies of the same code in arch/.

>  include/linux/of_device_node.h |  9 +++++++++

of_tpm.h would be the right name assuming we kept this structure which 
we shouldn't. Probably linux/tpm.h? Just a guess, I'm not familar with 
the TPM code really.


>  4 files changed, 42 insertions(+), 27 deletions(-)
>  create mode 100644 drivers/of/device_node.c
>  create mode 100644 include/linux/of_device_node.h
> 
> diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
> index a9ce66d09a75..5b18f4333ad1 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/of_device_node.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/drivers/of/Makefile b/drivers/of/Makefile
> index e0360a44306e..1c9feac450ad 100644
> --- a/drivers/of/Makefile
> +++ b/drivers/of/Makefile
> @@ -1,5 +1,5 @@
>  # SPDX-License-Identifier: GPL-2.0
> -obj-y = base.o device.o platform.o property.o
> +obj-y = base.o device.o platform.o property.o device_node.o
>  obj-$(CONFIG_OF_KOBJ) += kobj.o
>  obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
>  obj-$(CONFIG_OF_FLATTREE) += fdt.o
> diff --git a/drivers/of/device_node.c b/drivers/of/device_node.c
> new file mode 100644
> index 000000000000..71a19bc1bac2
> --- /dev/null
> +++ b/drivers/of/device_node.c
> @@ -0,0 +1,27 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/export.h>
> +#include <linux/of_device_node.h>
> +
> +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;
> +}
> +EXPORT_SYMBOL_GPL(of_tpm_get_sml_parameters);
> diff --git a/include/linux/of_device_node.h b/include/linux/of_device_node.h
> new file mode 100644
> index 000000000000..ae3faf023aab
> --- /dev/null
> +++ b/include/linux/of_device_node.h
> @@ -0,0 +1,9 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_OF_DEVICE_NODE_H
> +#define _LINUX_OF_DEVICE_NODE_H
> +
> +#include <linux/of.h>
> +
> +int of_tpm_get_sml_parameters(struct device_node *np, u64 *base, u32 *size);
> +
> +#endif /* _LINUX_OF_DEVICE_NODE_H */
> -- 
> 2.35.1
> 
>