[PATCH 5/5] firmware: scmi: Add OP-TEE transport

[Etienne Carriere]

On Tue, 9 Nov 2021 at 15:39, Patrick DELAUNAY
<patrick.delaunay at foss.st.com> wrote:
>
> Hi Etienne,
>
> one missing remark, don't see in my first review.
>
> On 11/4/21 3:14 PM, Etienne Carriere wrote:
> > This change implements an SCMI transport for agent interfacing the
> > OP-TEE SCMI service. OP-TEE provides an SCMI PTA (Pseudo-TA) for
> > non-secure world to send SCMI messages over an identified channel.
> > The driver implemented here uses a SMT shared memory for passing
> > messages between client and server.
> >
> > The implementation opens and releases channel resources for each
> > passed SCMI message so that resources allocated (sessions) or
> > registered (shared memory areas) in OP-TEE firmware are released for
> > example before relocation as the driver will likely allocate/register
> > them back when probed after relocation.
> >
> > The integration of the driver using dedicated config switch
> > CONFIG_SCMI_AGENT_OPTEE is designed on the model posted to the
> > U-Boot ML by Patrick Delaunay [1].
> >
> > Link: [1] https://lore.kernel.org/all/20211028191222.v3.4.Ib2e58ee67f4d023823d8b5404332dc4d7e847277@changeid/
> > Cc: Patrick Delaunay <patrick.delaunay at foss.st.com>
> > Cc: Wolfgang Denk <wd at denx.de>
> > Signed-off-by: Etienne Carriere <etienne.carriere at linaro.org>
> > ---
> >   drivers/firmware/scmi/Kconfig       |  14 +-
> >   drivers/firmware/scmi/Makefile      |   1 +
> >   drivers/firmware/scmi/optee_agent.c | 312 ++++++++++++++++++++++++++++
> >   3 files changed, 324 insertions(+), 3 deletions(-)
> >   create mode 100644 drivers/firmware/scmi/optee_agent.c
> >
> > diff --git a/drivers/firmware/scmi/Kconfig b/drivers/firmware/scmi/Kconfig
> > index c3a109beac..f9c69e5352 100644
> > --- a/drivers/firmware/scmi/Kconfig
> > +++ b/drivers/firmware/scmi/Kconfig
> > @@ -2,7 +2,7 @@ config SCMI_FIRMWARE
> >       bool "Enable SCMI support"
> >       select FIRMWARE
> >       select OF_TRANSLATE
> > -     depends on SANDBOX || DM_MAILBOX || ARM_SMCCC
> > +     depends on SANDBOX || DM_MAILBOX || ARM_SMCCC || OPTEE
> >       help
> >         System Control and Management Interface (SCMI) is a communication
> >         protocol that defines standard interfaces for power, performance
> > @@ -14,6 +14,14 @@ config SCMI_FIRMWARE
> >         or a companion host in the CPU system.
> >
> >         Communications between agent (client) and the SCMI server are
> > -       based on message exchange. Messages can be exchange over tranport
> > +       based on message exchange. Messages can be exchanged over transport
> >         channels as a mailbox device or an Arm SMCCC service with some
> > -       piece of identified shared memory.
> > +       piece of identified shared memory, or an OP-TEE SCMI service.
> > +
> > +config SCMI_AGENT_OPTEE
> > +     bool "Enable SCMI agent OP-TEE"
> > +     depends on SCMI_FIRMWARE && OPTEE
> > +     default y
> > +     help
> > +       Enable the SCMI communication channel based on OP-TEE transport
> > +       for compatible "linaro,scmi-optee".
> > diff --git a/drivers/firmware/scmi/Makefile b/drivers/firmware/scmi/Makefile
> > index 966475ec10..f72d06a400 100644
> > --- a/drivers/firmware/scmi/Makefile
> > +++ b/drivers/firmware/scmi/Makefile
> > @@ -2,4 +2,5 @@ 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-$(CONFIG_SCMI_AGENT_OPTEE)       += optee_agent.o
> >   obj-$(CONFIG_SANDBOX)               += sandbox-scmi_agent.o sandbox-scmi_devices.o
> > diff --git a/drivers/firmware/scmi/optee_agent.c b/drivers/firmware/scmi/optee_agent.c
> > new file mode 100644
> > index 0000000000..8232af2f41
> > --- /dev/null
> > +++ b/drivers/firmware/scmi/optee_agent.c
> > @@ -0,0 +1,312 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2020-2021 Linaro Limited.
> > + */
> > +
>
> (...)
>
> > +
> > +static int scmi_optee_of_to_plat(struct udevice *dev)
> > +{
> > +     struct scmi_optee_channel *chan = dev_get_plat(dev);
> > +     int ret;
> > +
> > +     if (dev_read_u32(dev, "linaro,optee-channel-id", &chan->channel_id)) {
> > +             dev_err(dev, "Missing property linaro,channel-id\n");
>
> Can you use the correct property name in the error message = "linaro,optee-channel-id"
>
> +               dev_err(dev, "Missing property linaro,optee-channel-id\n");
>

nice catch.
Thanks, I'll post a v2.

Etienne

>
> Patrick
>