firmware: arm_scmi: optee: Drop the support for the OPTEE shared dynamic buffer

The shared memory buffer allocated by the optee driver is normal cached
memory and can't be used with IOMEM APIs used in shmem_*.

We currently support only IO memory for shared memory and supporting
normal cached memory needs more changes and needs to be thought through
properly. So for now, let us drop the support for this OPTEE shared buffer.

Link: https://lore.kernel.org/r/20211125150730.188487-1-sudeep.holla@arm.com
Cc: Cristian Marussi <cristian.marussi@arm.com>
Cc: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/optee.c

@@ -282,23 +282,6 @@ static void scmi_optee_clear_channel(struct scmi_chan_info *cinfo)
 	shmem_clear_channel(channel->shmem);
 }
 
-static int setup_dynamic_shmem(struct device *dev, struct scmi_optee_channel *channel)
-{
-	const size_t msg_size = SCMI_OPTEE_MAX_MSG_SIZE;
-
-	channel->tee_shm = tee_shm_alloc_kernel_buf(scmi_optee_private->tee_ctx, msg_size);
-	if (IS_ERR(channel->tee_shm)) {
-		dev_err(channel->cinfo->dev, "shmem allocation failed\n");
-		return -ENOMEM;
-	}
-
-	channel->shmem = (void *)tee_shm_get_va(channel->tee_shm, 0);
-	memset(channel->shmem, 0, msg_size);
-	shmem_clear_channel(channel->shmem);
-
-	return 0;
-}
-
 static int setup_static_shmem(struct device *dev, struct scmi_chan_info *cinfo,
 			      struct scmi_optee_channel *channel)
 {
@@ -342,7 +325,7 @@ static int setup_shmem(struct device *dev, struct scmi_chan_info *cinfo,
 	if (of_find_property(cinfo->dev->of_node, "shmem", NULL))
 		return setup_static_shmem(dev, cinfo, channel);
 	else
-		return setup_dynamic_shmem(dev, channel);
+		return -ENOMEM;
 }
 
 static int scmi_optee_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, bool tx)