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Message-ID: <YmKmFxailmd5AeqF@e120937-lin>
Date: Fri, 22 Apr 2022 13:56:55 +0100
From: Cristian Marussi <cristian.marussi@....com>
To: Etienne Carriere <etienne.carriere@...aro.org>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Sudeep Holla <sudeep.holla@....com>,
Vincent Guittot <vincent.guittot@...aro.org>
Subject: Re: [PATCH v2] firmware: arm_scmi: support optee shared memory in
optee transport
On Thu, Apr 21, 2022 at 09:49:35AM +0200, Etienne Carriere wrote:
> Adds support for tee shared memory in optee scmi transport. When using
> tee shared memory, scmi optee transport manages SCMI messages using
> msg protocol (from msg.c) in shared memory, whereas smt (from shmem.c)
> protocol is used with static IOMEM shared buffers.
>
> Signed-off-by: Etienne Carriere <etienne.carriere@...aro.org>
>
Hi Etienne,
the bot complaints on linking failure are due to a missing dependency:
diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig
index 7794bd41eaa0..1e7b7fec97d9 100644
--- a/drivers/firmware/arm_scmi/Kconfig
+++ b/drivers/firmware/arm_scmi/Kconfig
@@ -59,6 +59,7 @@ config ARM_SCMI_TRANSPORT_OPTEE
depends on OPTEE=y || OPTEE=ARM_SCMI_PROTOCOL
select ARM_SCMI_HAVE_TRANSPORT
select ARM_SCMI_HAVE_SHMEM
+ select ARM_SCMI_HAVE_MSG
default y
help
This enables the OP-TEE service based transport for SCMI.
needed when you compile without any other transport using MSGs.
One remark down below.
> drivers/firmware/arm_scmi/optee.c | 128 ++++++++++++++++++++++++------
> 1 file changed, 104 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/firmware/arm_scmi/optee.c b/drivers/firmware/arm_scmi/optee.c
> index 8302a2b4aeeb..6676b17d2587 100644
> --- a/drivers/firmware/arm_scmi/optee.c
> +++ b/drivers/firmware/arm_scmi/optee.c
> @@ -64,6 +64,22 @@ enum scmi_optee_pta_cmd {
> * [in] value[0].b: Requested capabilities mask (enum pta_scmi_caps)
> */
> PTA_SCMI_CMD_GET_CHANNEL = 3,
> +
> + /*
> + * PTA_SCMI_CMD_PROCESS_MSG_CHANNEL - Process SCMI message in a MSG
> + * buffer pointed by memref parameters
> + *
> + * [in] value[0].a: Channel handle
> + * [in] memref[1]: Message buffer (MSG and SCMI payload)
> + * [out] memref[2]: Response buffer (MSG and SCMI payload)
> + *
> + * Shared memories used for SCMI message/response are MSG buffers
> + * referenced by param[1] and param[2]. MSG transport protocol
> + * uses a 32bit header to carry SCMI meta-data (protocol ID and
> + * protocol message ID) followed by the effective SCMI message
> + * payload.
> + */
> + PTA_SCMI_CMD_PROCESS_MSG_CHANNEL = 4,
> };
>
> /*
> @@ -72,9 +88,17 @@ enum scmi_optee_pta_cmd {
> * PTA_SCMI_CAPS_SMT_HEADER
> * When set, OP-TEE supports command using SMT header protocol (SCMI shmem) in
> * shared memory buffers to carry SCMI protocol synchronisation information.
> + *
> + * PTA_SCMI_CAPS_MSG_HEADER
> + * When set, OP-TEE supports command using MSG header protocol in an OP-TEE
> + * shared memory to carry SCMI protocol synchronisation information and SCMI
> + * message payload.
> */
> #define PTA_SCMI_CAPS_NONE 0
> #define PTA_SCMI_CAPS_SMT_HEADER BIT(0)
> +#define PTA_SCMI_CAPS_MSG_HEADER BIT(1)
> +#define PTA_SCMI_CAPS_MASK (PTA_SCMI_CAPS_SMT_HEADER | \
> + PTA_SCMI_CAPS_MSG_HEADER)
>
> /**
> * struct scmi_optee_channel - Description of an OP-TEE SCMI channel
> @@ -85,7 +109,8 @@ enum scmi_optee_pta_cmd {
> * @mu: Mutex protection on channel access
> * @cinfo: SCMI channel information
> * @shmem: Virtual base address of the shared memory
> - * @tee_shm: Reference to TEE shared memory or NULL if using static shmem
> + * @req: Shared memory protocol handle for SCMI request and synchronous response
> + * @tee_shm: TEE shared memory handle @req or NULL if using IOMEM shmem
> * @link: Reference in agent's channel list
> */
> struct scmi_optee_channel {
> @@ -94,7 +119,10 @@ struct scmi_optee_channel {
> u32 caps;
> struct mutex mu;
> struct scmi_chan_info *cinfo;
> - struct scmi_shared_mem __iomem *shmem;
> + union {
> + struct scmi_shared_mem __iomem *shmem;
> + struct scmi_msg_payld *msg;
> + } req;
> struct tee_shm *tee_shm;
> struct list_head link;
> };
> @@ -178,8 +206,8 @@ static int get_capabilities(struct scmi_optee_agent *agent)
>
> caps = param[0].u.value.a;
>
> - if (!(caps & PTA_SCMI_CAPS_SMT_HEADER)) {
> - dev_err(agent->dev, "OP-TEE SCMI PTA doesn't support SMT\n");
> + if (!(caps & (PTA_SCMI_CAPS_SMT_HEADER | PTA_SCMI_CAPS_MSG_HEADER))) {
> + dev_err(agent->dev, "OP-TEE SCMI PTA doesn't support SMT and MSG\n");
> return -EOPNOTSUPP;
> }
>
> @@ -193,9 +221,14 @@ static int get_channel(struct scmi_optee_channel *channel)
> struct device *dev = scmi_optee_private->dev;
> struct tee_ioctl_invoke_arg arg = { };
> struct tee_param param[1] = { };
> - unsigned int caps = PTA_SCMI_CAPS_SMT_HEADER;
> + unsigned int caps = 0;
> int ret;
>
> + if (channel->tee_shm)
> + caps = PTA_SCMI_CAPS_MSG_HEADER;
> + else
> + caps = PTA_SCMI_CAPS_SMT_HEADER;
> +
> arg.func = PTA_SCMI_CMD_GET_CHANNEL;
> arg.session = channel->tee_session;
> arg.num_params = 1;
> @@ -249,6 +282,37 @@ static int invoke_process_smt_channel(struct scmi_optee_channel *channel)
> return 0;
> }
>
Looking at the invoke_process_smt_channel() code, I see that it still refers to
->tee_shm in an if condition when you send a PTA_SCMI_CMD_PROCESS_SMT_CHANNEL_MESSAGE
but that channel->tee_shm is always NULL when calling invoke_process_smt_channel()
since tee_shm is only allocated by non-SMT transport via setup_dynamic_shmem(),
so when this if-branch inside invoke_process_smt_channel() is supposed
to be used ? or is it a leftover ? (or I am missing something :D)
> +static int invoke_process_msg_channel(struct scmi_optee_channel *channel, size_t msg_size)
> +{
> + struct tee_ioctl_invoke_arg arg = {
> + .func = PTA_SCMI_CMD_PROCESS_MSG_CHANNEL,
> + .session = channel->tee_session,
> + .num_params = 3,
> + };
> + struct tee_param param[3] = { };
> + int ret;
> +
> + param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
> + param[0].u.value.a = channel->channel_id;
> +
> + param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
> + param[1].u.memref.shm = channel->tee_shm;
> + param[1].u.memref.size = msg_size;
> +
> + param[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
> + param[2].u.memref.shm = channel->tee_shm;
> + param[2].u.memref.size = SCMI_OPTEE_MAX_MSG_SIZE;
> +
> + ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
> + if (ret < 0 || arg.ret) {
> + dev_err(scmi_optee_private->dev, "Can't invoke channel %u: %d / %#x\n",
> + channel->channel_id, ret, arg.ret);
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
Thanks,
Cristian
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