Re: [PATCH 1/4] ufs: move ICE functionality to a common library

[Eric Biggers <ebiggers@kernel.org>]

On Wed, Nov 03, 2021 at 04:18:37PM -0700, Gaurav Kashyap wrote:
> The Inline Crypto Engine functionality is not limited to
> ufs and it can be used by other storage controllers like emmc
> which have the HW capabilities. It would be better to move this
> functionality to a common location.

I think you should be a bit more concrete here: both sdhci-msm and ufs-qcom
already have ICE support, and this common library allows code to be shared.

> Moreover, when wrapped key functionality is added, it would
> reduce the effort required to add it for all storage
> controllers.
> 
> Signed-off-by: Gaurav Kashyap <quic_gaurkash@quicinc.com>
> ---
>  drivers/scsi/ufs/ufs-qcom-ice.c   | 172 ++++--------------------------
>  drivers/soc/qcom/Kconfig          |   7 ++
>  drivers/soc/qcom/Makefile         |   1 +
>  drivers/soc/qcom/qti-ice-common.c | 135 +++++++++++++++++++++++
>  drivers/soc/qcom/qti-ice-regs.h   | 145 +++++++++++++++++++++++++
>  include/linux/qti-ice-common.h    |  26 +++++
>  6 files changed, 334 insertions(+), 152 deletions(-)
>  create mode 100644 drivers/soc/qcom/qti-ice-common.c
>  create mode 100644 drivers/soc/qcom/qti-ice-regs.h
>  create mode 100644 include/linux/qti-ice-common.h

This should be split up into two patches: one that adds the library, and one
that converts ufs-qcom to use it.  There should also be a third patch that
converts sdhci-msm to use it.

> +static void get_ice_mmio_data(struct ice_mmio_data *data,
> +			      const struct ufs_qcom_host *host)
> +{
> +	data->ice_mmio = host->ice_mmio;
> +}

I think the struct ice_mmio_data should just be a field of struct ufs_qcom_host.
Then you wouldn't have to keep initializing a new one.

> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index 79b568f82a1c..39f223ed8cdd 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -209,4 +209,11 @@ config QCOM_APR
>  	  application processor and QDSP6. APR is
>  	  used by audio driver to configure QDSP6
>  	  ASM, ADM and AFE modules.
> +
> +config QTI_ICE_COMMON
> +	tristate "QTI common ICE functionality"
> +	depends on SCSI_UFS_CRYPTO && SCSI_UFS_QCOM
> +	help
> +	  Enable the common ICE library that can be used
> +	  by UFS and EMMC drivers for ICE functionality.

"Libraries" should not be user-selectable.  Instead, they should be selected by
the kconfig options that need them.  That also means that the "depends on"
clause should not be here.

So it should look more like:

config QTI_ICE_COMMON
	tristate
	help
	  Enable the common ICE library that can be used
	  by UFS and EMMC drivers for ICE functionality.

If the library itself has dependencies (perhaps ARCH_QCOM?), then add those.

> +
> +int qti_ice_init(const struct ice_mmio_data *mmio)
> +{
> +	return qti_ice_supported(mmio);
> +}
> +EXPORT_SYMBOL(qti_ice_init);

Please use EXPORT_SYMBOL_GPL instead of EXPORT_SYMBOL.

The exported functions could also use kerneldoc comments.

> diff --git a/include/linux/qti-ice-common.h b/include/linux/qti-ice-common.h
> new file mode 100644
> index 000000000000..433422b34a7d
> --- /dev/null
> +++ b/include/linux/qti-ice-common.h
> @@ -0,0 +1,26 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2021, The Linux Foundation. All rights reserved.
> + */
> +
> +#ifndef _QTI_ICE_COMMON_H
> +#define _QTI_ICE_COMMON_H
> +
> +#include <linux/types.h>
> +#include <linux/device.h>
> +
> +#define AES_256_XTS_KEY_SIZE    64

Is the definition of AES_256_XTS_KEY_SIZE needed in this header?  It's not
properly "namespaced", so it's sort of the odd thing out in this header.

- Eric