firmware: arm_scmi: Fix response size warning for OPTEE transport

Some protocols check the response size with the expected value but optee
shared memory doesn't return such size whereas it is available in the
optee output buffer.

As an example, the base protocol compares the response size with the
expected result when requesting the list of protocol which triggers a
warning with optee shared memory:

arm-scmi firmware:scmi0: Malformed reply - real_sz:116  calc_sz:4  (loop_num_ret:4)

Save the output buffer length and use it when fetching the answer.

Link: https://lore.kernel.org/r/20220624074549.3298-1-vincent.guittot@linaro.org
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/firmware/arm_scmi/optee.c b/drivers/firmware/arm_scmi/optee.c
index b503c22cfd326831cb612ae2d1dde004e3b0b0a9..8abace56b95885da4ccb9d52488083996c234e9e 100644 (file)
--- a/drivers/firmware/arm_scmi/optee.c
+++ b/drivers/firmware/arm_scmi/optee.c
@@ -117,6 +117,7 @@ struct scmi_optee_channel {
        u32 channel_id;
        u32 tee_session;
        u32 caps;
+       u32 rx_len;
        struct mutex mu;
        struct scmi_chan_info *cinfo;
        union {
@@ -302,6 +303,9 @@ static int invoke_process_msg_channel(struct scmi_optee_channel *channel, size_t
                return -EIO;
        }
 
+       /* Save response size */
+       channel->rx_len = param[2].u.memref.size;
+
        return 0;
 }
 
@@ -353,6 +357,7 @@ static int setup_dynamic_shmem(struct device *dev, struct scmi_optee_channel *ch
        shbuf = tee_shm_get_va(channel->tee_shm, 0);
        memset(shbuf, 0, msg_size);
        channel->req.msg = shbuf;
+       channel->rx_len = msg_size;
 
        return 0;
 }
@@ -508,7 +513,7 @@ static void scmi_optee_fetch_response(struct scmi_chan_info *cinfo,
        struct scmi_optee_channel *channel = cinfo->transport_info;
 
        if (channel->tee_shm)
-               msg_fetch_response(channel->req.msg, SCMI_OPTEE_MAX_MSG_SIZE, xfer);
+               msg_fetch_response(channel->req.msg, channel->rx_len, xfer);
        else
                shmem_fetch_response(channel->req.shmem, xfer);
 }