[PATCH v3 3/8] firmware: scmi: support Arm SMCCC transport

[Simon Glass]

Hi Etienne,

On Mon, 7 Sep 2020 at 08:50, Etienne Carriere
<etienne.carriere at linaro.org> wrote:
>
> This change implements a SMCCC transport for SCMI exchanges. This
> implementation follows the Linux kernel as references implementation
> for SCMI message processing, using the SMT format for communication
> channel meta-data.
>
> Use of SMCCC transport in SCMI FDT bindings are defined in the Linux
> kernel DT bindings since v5.8. SMCCC with SMT is implemented in OP-TEE
> from tag 3.9.0 [2].
>
> Links: [2] https://github.com/OP-TEE/optee_os/commit/a58c4d706d23
> Signed-off-by: Etienne Carriere <etienne.carriere at linaro.org>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Peng Fan <peng.fan at nxp.com>
> Cc: Sudeep Holla <sudeep.holla at arm.com>
> ---
>
> Changes in v3:
> - This is a followup of the SCMI agent patches posted in
>   https://patchwork.ozlabs.org/project/uboot/list/?series=196253
>   The v3 splits commits and introduces a new uclass as requested.
> - This patch implements the same Arm SMCCC SCMI agent as presented
>   in v2 but in its own source file smccc_agent.c, and based in smt.h.
> ---
>  drivers/firmware/scmi/Kconfig       |  4 +-
>  drivers/firmware/scmi/Makefile      |  1 +
>  drivers/firmware/scmi/smccc_agent.c | 95 +++++++++++++++++++++++++++++
>  3 files changed, 98 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/firmware/scmi/smccc_agent.c
>

Reviewed-by: Simon Glass <sjg at chromium.org>

nits below

> diff --git a/drivers/firmware/scmi/Kconfig b/drivers/firmware/scmi/Kconfig
> index c501bf4943..335d09c821 100644
> --- a/drivers/firmware/scmi/Kconfig
> +++ b/drivers/firmware/scmi/Kconfig
> @@ -15,5 +15,5 @@ config SCMI_FIRMWARE
>
>           Communications between agent (client) and the SCMI server are
>           based on message exchange. Messages can be exchange over tranport
> -         channels as a mailbox device with some piece of identified shared
> -         memory.
> +         channels as a mailbox device or an Arm SMCCC service with some
> +         piece of identified shared memory.
> diff --git a/drivers/firmware/scmi/Makefile b/drivers/firmware/scmi/Makefile
> index d22f53efe7..2f782bbd55 100644
> --- a/drivers/firmware/scmi/Makefile
> +++ b/drivers/firmware/scmi/Makefile
> @@ -1,4 +1,5 @@
>  obj-y  += scmi_agent-uclass.o
>  obj-y  += smt.o
> +obj-$(CONFIG_ARM_SMCCC)        += smccc_agent.o
>  obj-$(CONFIG_DM_MAILBOX)       += mailbox_agent.o
>  obj-$(CONFIG_SANDBOX)          += sandbox-scmi_agent.o
> diff --git a/drivers/firmware/scmi/smccc_agent.c b/drivers/firmware/scmi/smccc_agent.c
> new file mode 100644
> index 0000000000..90707710e2
> --- /dev/null
> +++ b/drivers/firmware/scmi/smccc_agent.c
> @@ -0,0 +1,95 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2020 Linaro Limited.
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <errno.h>
> +#include <scmi_agent.h>
> +#include <scmi_agent-uclass.h>
> +#include <dm/devres.h>
> +#include <linux/arm-smccc.h>
That should go below the next one.
> +
> +#include <dm/device-internal.h>
> +#include <linux/compat.h>
> +
> +#include "smt.h"
> +
> +#define SMCCC_RET_NOT_SUPPORTED         ((unsigned long)-1)
> +
> +/**
> + * struct scmi_smccc_channel - Description of an SCMI SMCCC transport
> + * @func_id:   SMCCC function ID used by the SCMI transport
> + * @smt:       Shared memory buffer
> + */
> +struct scmi_smccc_channel {
> +       ulong func_id;
> +       struct scmi_smt smt;
> +};
> +
> +static struct scmi_smccc_channel *scmi_smccc_get_priv(struct udevice *dev)
> +{
> +       return (struct scmi_smccc_channel *)dev_get_priv(dev);

You shouldn't need that cast

[..]

Regards,
Simon