On Thu, Jul 15, 2021 at 06:36:26PM +0200, Peter Hilber wrote:

On 12.07.21 16:18, Cristian Marussi wrote:

quoted

From: Peter Hilber <redacted>

Add abstractions for future transports using message passing, such as
virtio. Derive the abstractions from the shared memory abstractions.

Abstract the transport SDU through the opaque struct scmi_msg_payld.
Also enable the transport to determine all other required information
about the transport SDU.

Signed-off-by: Peter Hilber <redacted>
[ Cristian: Adapted to new SCMI Kconfig layout, updated Copyrigths ]
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v4 --> v5
- adapted to new SCMI Kconfig
- removed raw_payload msg helpers
v3 --> v4
- added raw_payload msg helpers
---
  drivers/firmware/arm_scmi/Kconfig  |   6 ++
  drivers/firmware/arm_scmi/Makefile |   1 +
  drivers/firmware/arm_scmi/common.h |  15 ++++
  drivers/firmware/arm_scmi/msg.c    | 113 +++++++++++++++++++++++++++++
  4 files changed, 135 insertions(+)
  create mode 100644 drivers/firmware/arm_scmi/msg.c

diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig
index ee6517b24080..1fdaa8ad7d3f 100644
--- a/drivers/firmware/arm_scmi/Kconfig
+++ b/drivers/firmware/arm_scmi/Kconfig

@@ -34,6 +34,12 @@ config ARM_SCMI_HAVE_SHMEM
  	  This declares whether a shared memory based transport for SCMI is
  	  available.
+config ARM_SCMI_HAVE_MSG
+	bool
+	help
+	  This declares whether a message passing based transport for SCMI is
+	  available.
+
  config ARM_SCMI_TRANSPORT_MAILBOX
  	bool "SCMI transport based on Mailbox"
  	depends on ARM_SCMI_PROTOCOL && MAILBOX

diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index e0e6bd3dba9e..aaad9f6589aa 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile

@@ -4,6 +4,7 @@ scmi-driver-y = driver.o notify.o
  scmi-transport-$(CONFIG_ARM_SCMI_HAVE_SHMEM) = shmem.o
  scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_MAILBOX) += mailbox.o
  scmi-transport-$(CONFIG_ARM_SCMI_TRANSPORT_SMC) += smc.o
+scmi-transport-$(CONFIG_ARM_SCMI_HAVE_MSG) += msg.o
  scmi-protocols-y = base.o clock.o perf.o power.o reset.o sensors.o system.o voltage.o
  scmi-module-objs := $(scmi-bus-y) $(scmi-driver-y) $(scmi-protocols-y) \
  		    $(scmi-transport-y)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 14457f0d5dea..7a1e84dc191b 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h

@@ -415,6 +415,21 @@ void shmem_clear_channel(struct scmi_shared_mem __iomem *shmem);
  bool shmem_poll_done(struct scmi_shared_mem __iomem *shmem,
  		     struct scmi_xfer *xfer);
+/* declarations for message passing transports */
+struct scmi_msg_payld;
+
+/* Maximum overhead of message w.r.t. struct scmi_desc.max_msg_size */
+#define SCMI_MSG_MAX_PROT_OVERHEAD (2 * sizeof(__le32))
+
+size_t msg_response_size(struct scmi_xfer *xfer);
+size_t msg_command_size(struct scmi_xfer *xfer);
+void msg_tx_prepare(struct scmi_msg_payld *msg, struct scmi_xfer *xfer);
+u32 msg_read_header(struct scmi_msg_payld *msg);
+void msg_fetch_response(struct scmi_msg_payld *msg, size_t len,
+			struct scmi_xfer *xfer);
+void msg_fetch_notification(struct scmi_msg_payld *msg, size_t len,
+			    size_t max_len, struct scmi_xfer *xfer);
+
  void scmi_notification_instance_data_set(const struct scmi_handle *handle,
  					 void *priv);
  void *scmi_notification_instance_data_get(const struct scmi_handle *handle);

diff --git a/drivers/firmware/arm_scmi/msg.c b/drivers/firmware/arm_scmi/msg.c
new file mode 100644
index 000000000000..639969b7dc10
--- /dev/null
+++ b/drivers/firmware/arm_scmi/msg.c

@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * For transports using message passing.
+ *
+ * Derived from shm.c.
+ *
+ * Copyright (C) 2019-2021 ARM Ltd.
+ * Copyright (C) 2020-2021 OpenSynergy GmbH
+ */
+
+#include <linux/io.h>
+#include <linux/processor.h>

The above two includes appear to be unnecessary.

Right. Thanks, I'll fix.

Cristian


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