[PATCH v8 00/17] Introduce a unified API for SCMI Server testing

[PATCH v8 00/17] Introduce a unified API for SCMI Server testing

[Cristian Marussi]

Hi all,

This series aims to introduce a new SCMI unified userspace interface meant
to ease testing an SCMI Server implementation for compliance, fuzzing etc.,
from the perspective of the OSPM agent (non-secure world only ...)

It is proposed as a testing/development facility, it is NOT meant to be a
feature to use in production, but only enabled in Kconfig for test
deployments.

Currently an SCMI Compliance Suite like the one at [1] can only work by
injecting SCMI messages at the SCMI transport layer using the mailbox test
driver (CONFIG_MAILBOX_TEST) via its few debugfs entries and looking at
the related replies from the SCMI backend Server.

This approach has a few drawbacks:

- the SCMI Server under test MUST be reachable through a mailbox based
  SCMI transport: any other SCMI Server placement is not possible (like in
  a VM reachable via SCMI Virtio). In order to cover other placements in
  the current scenario we should write some sort of test driver for each
  and every existent SCMI transport and for any future additional transport
  ...this clearly does not scale.

- even in the mailbox case the userspace Compliance suite cannot simply
  send and receive bare SCMI messages BUT it has to properly lay them out
  into the shared memory exposed by the mailbox test driver as expected by
  the transport definitions. In other words such a userspace test
  application has to, not only use a proper transport driver for the system
  at hand, but it also has to have a comprehensive knowledge of the
  internals of the underlying transport in order to operate.

- last but not least, the system under test has to be specifically
  configured and built, in terms of Kconfig and DT, to perform such kind of
  testing, it cannot be used for anything else, which is unfortunate for
  CI/CD deployments.

This series introduces a new SCMI Raw mode support feature that, when
configured and enabled exposes a new interface in debugfs through which:

- a userspace application can inject bare SCMI binary messages into the
  SCMI core stack; such messages will be routed by the SCMI regular kernel
  stack to the backend Server using the currently configured transport
  transparently: in other words you can test the SCMI server, no matter
  where it is placed, as long as it is reachable from the currently
  configured SCMI stack.
  Same goes the other way around on the reading path: any SCMI server reply
  can be read as a bare SCMI binary message from the same debugfs path.

- as a direct consequence of this way of injecting bare messages in the
  middle of the SCMI stack (instead of beneath it at the transport layer)
  the user application has to handle only bare SCMI messages without having
  to worry about the specific underlying transport internals that will be
  taken care of by the SCMI core stack itself using its own machinery,
  without duplicating such logic.

- a system under test, once configured with SCMI Raw support enabled in
  Kconfig, can be booted without any particular DT change.

Latest V6 additions: 

 - improved scmi traces for msg dumps to include used channels
 - added a new common SCMI debugfs root fs
 - reworked SCMI Raw debugfs layout
 - added support of a new additional per-channel API that allows a user to
   select a specific egress channel for the message injection (when more
   than one channel is available)

A quick and trivial example from the shell...reading from a sensor by
injecting a properly crafted packet in raw mode (letting the stack select
the channel):

	# INJECT THE SENSOR_READING MESSAGE FOR SENSOR ID=1 (binary little endian)
	root@deb-buster-arm64:~# echo -e -n \\x06\\x54\\x00\\x00\\x01\\x00\\x00\\x00\\x00\\x00\\x00\\x00 > /sys/kernel/debug/scmi/0/raw/message

	# READING BACK THE REPLY...
	root@deb-buster-arm64:~# cat /sys/kernel/debug/scmi/0/raw/message | od --endian=little -t x4
	0000000 00005406 00000000 00000335 00000000
	0000020

while doing that, since Raw mode makes (partial) use of the regular SCMI
stack, you can observe the messages going through the SCMI stack with the
usual traces:

              bash-329     [000] ..... 14183.446808: scmi_msg_dump: id=0 ch=10 pt=15 t=cmnd msg_id=06 seq=0000 s=0 pyld=0100000000000000
   irq/35-mhu_db_l-81      [000] ..... 14183.447809: scmi_msg_dump: id=0 ch=10 pt=15 t=resp msg_id=06 seq=0000 s=0 pyld=3503000000000000

..trying to read in async when the backend server does NOT supports asyncs:

	# AN ASYNC SENSOR READING REQUEST...
	root@deb-buster-arm64:~# echo -e -n \\x06\\x54\\x00\\x00\\x01\\x00\\x00\\x00\\x01\\x00\\x00\\x00 > /sys/kernel/debug/scmi/0/raw/message_async

              bash-329     [000] ..... 16415.938739: scmi_msg_dump: id=0 ch=10 pt=15 t=cmnd msg_id=06 seq=0000 s=0 pyld=0100000001000000
   irq/35-mhu_db_l-81      [000] ..... 16415.944129: scmi_msg_dump: id=0 ch=10 pt=15 t=resp msg_id=06 seq=0000 s=-1 pyld=

	# RETURNS A STATUS -1 FROM THE SERVER NOT SUPPORTING IT
	root@deb-buster-arm64:~# cat /sys/kernel/debug/scmi/0/raw/message | od --endian=little -t x4
	0000000 00005406 ffffffff
	0000010

Note that the above example was on a JUNO, BUT exactly the same steps can
be used to reach an SCMI Server living on a VM reachable via virtio as
long as the system under test if properly configured to work with a
virtio transport.

In a nutshell the exposed API is as follows:

/sys/kernel/debug/scmi/
`-- 0
    |-- atomic_threshold_us
    |-- instance_name
    |-- raw
    |   |-- channels
    |   |   |-- 0x10
    |   |   |   |-- message
    |   |   |   `-- message_async
    |   |   `-- 0x13
    |   |       |-- message
    |   |       `-- message_async
    |   |-- errors
    |   |-- message
    |   |-- message_async
    |   |-- notification
    |   `-- reset
    `-- transport
        |-- is_atomic
        |-- max_msg_size
        |-- max_rx_timeout_ms
        |-- rx_max_msg
        |-- tx_max_msg
        `-- type

... where at the top level:

 - <N>: a progressive sequence number identifying this SCMI instance, in
   case there are multiple SCMI instance defined
   
 - instance_name: can be used (by CI) to identify the SCMI instance <N>
   that you are using through this Raw accessors: it corresponds to the SCMI
   DT top node full name of the underlying SCMI instance


... rooted under /transport:

 - a bunch of configuration info useful to setup the user application
   expectations in terms of timeouts and message characteristics.


... rooted at /raw (the real SCMI Raw interface :D):

 - message*: used to send sync/async commands and read back immediate and
   delayed responses (if any)
 - errors: used to report timeout and unexpected replies
 - reset: used to reset the SCMI Raw stack, flushing all queues from
   received messages still pending to be read out (useful to be sure to
   cleanup between test suite runs...)
 - notification: used to read any notification being spit by the system
   (if previously enabled by the user app)


... rooted at /raw/channels/<M>/:

 - message*: used to send sync/async commands and read back immediate and
   delayed responses (if any), using a SPECIFIC transport channel <M>
   (instead of letting the system choose for you based on transport config
    and the rotocol embedded in the injected message)
   NOTE THAT these entries are optional, created only if there is more than
   transport channel defined on the system.

Each write corresponds to one command request and the replies or delayed
response are read back one message at time (receiving an EOF at each
message boundary).

The user application running the test is in charge of handling timeouts
and properly choosing SCMI sequence numbers for the outgoing requests: note
that the same fixed number can be re-used (...though discouraged...) as
long as the suite does NOT expect to send multiple in-flight commands
concurrently.

Since the SCMI core regular stack is partially used to deliver and collect
the messages, late replies after timeouts and any other sort of unexpected
message sent by the SCMI server platform back can be identified by the SCMI
core as usual and it will be reported under /errors for later analysis.
(a userspace test-app will have anyway properly detected the timeout on
 /message* ...)

All of the above has been roughly tested against a standard JUNO SCP SCMI
Server (mailbox trans) and an emulated SCMI Server living in a VM (virtio
trans) using a custom experimental version of the scmi-tests Compliance
suite patched to support Raw mode and posted at [2]. (still in development
...merge requests are in progress...for now it is just a mean for me to
test the testing API ... O_o)

This V8 series is based on v6.2-rc1 PLUS another series which reworked a
bit the SCMI core stack init/probe [3]; to ease testing a V8 properly
based can be picked up from [4].

Having said that (in such a concise and brief way :P) ...
	
...any feedback/comments are welcome !

Thanks,
Cristian

---
v7 --> v8 
- fixed a few bad handling on error path
- ignoring debugfs_ retvals as supposed to
- using XArray for per-channel queus instead of IDRs
- refactored debugfs setup calls

v6 --> v7
- fixed one sparse error
- removed redundant info.num_chans/channels fields: enumerate them dyamically
  once needed.

v5 --> v6
- exported symbol debugfs_create_str 
- rebased on top of v6.2-rc1 plus series at [3]
- redesigned SCMI debugfs layout with a bunch of common entries
  enabled by implicit CONFIG_ARM_SCMI_NEED_DEBUGFS
- refactored SCMI Raw internal queues handling
- added SCMI Raw per-channel injection support
- added channels info on SCMI msg_dump traces
- fix debugfs multiple writers cases
- added DEBUG_FS dependency to Raw mode
- select CONFIG_ARM_SCMI_NEED_DEBUGFS when Raw mode is compiled

v4 --> v5
- rebased on sudeep/for-next/scmi
- added multiple SCMI instances support
- added optional Raw full-cohexistence mode
- use custom tags to distinguish Raw msg_dump traces
- add circular handling of raw buffers queues for errors and notifications

V3 --> v4
- rebased on v6.1-rc1
- addedd missing support for 'polled' transports and transport lacking a
  completion_irq (like smc/optee)
- removed a few inlines
- refactored SCMI Raw RX patch to make use more extensively of the regular
  non-Raw RX path
- fix handling of O_NONBLOCK raw_mode read requests

v2 --> v3
- fixed some sparse warning on LE and __poll_t
- reworked and simplified deferred worker in charge of xfer delayed waiting
- allow for injection of DT-unknown protocols messages when in Raw mode
  (needed for any kind of fuzzing...)

v1 --> v2
- added comments and debugfs docs
- added dedicated transport devices for channels initialization
- better channels handling in Raw mode
- removed runtime enable, moved to static compile time exclusion
  of SCMI regular stack

[1]: https://gitlab.arm.com/tests/scmi-tests
[2]: https://gitlab.arm.com/tests/scmi-tests/-/commits/raw_mode_support_devel/
[3]: https://lore.kernel.org/all/20221222185049.737625-1-cristian.marussi@arm.com/
[4]: https://gitlab.arm.com/linux-arm/linux-cm/-/commits/scmi_raw_mode_V8/


Cristian Marussi (17):
  firmware: arm_scmi: Refactor xfer in-flight registration routines
  firmware: arm_scmi: Refactor polling helpers
  firmware: arm_scmi: Refactor scmi_wait_for_message_response
  firmware: arm_scmi: Add flags field to xfer
  firmware: arm_scmi: Add xfer Raw helpers
  firmware: arm_scmi: Move errors defs and code to common.h
  firmware: arm_scmi: Add internal platform/channel IDs
  include: trace: Add platform and channel instance references
  debugfs: Export debugfs_create_str symbol
  firmware: arm_scmi: Populate a common SCMI debugsfs root
  firmware: arm_scmi: Add debugfs ABI documentation for common entries
  firmware: arm_scmi: Add core Raw transmission support
  firmware: arm_scmi: Add debugfs ABI documentation for Raw mode
  firmware: arm_scmi: Reject SCMI drivers while in Raw mode
  firmware: arm_scmi: Call Raw mode hooks from the core stack
  firmware: arm_scmi: Add Raw mode coexistence support
  firmware: arm_scmi: Add per-channel Raw injection support

 Documentation/ABI/testing/debugfs-scmi     |   70 +
 Documentation/ABI/testing/debugfs-scmi-raw |  109 ++
 drivers/firmware/arm_scmi/Kconfig          |   32 +
 drivers/firmware/arm_scmi/Makefile         |    1 +
 drivers/firmware/arm_scmi/bus.c            |    7 +
 drivers/firmware/arm_scmi/common.h         |   75 +
 drivers/firmware/arm_scmi/driver.c         |  638 +++++++--
 drivers/firmware/arm_scmi/protocols.h      |    7 +
 drivers/firmware/arm_scmi/raw_mode.c       | 1443 ++++++++++++++++++++
 drivers/firmware/arm_scmi/raw_mode.h       |   31 +
 fs/debugfs/file.c                          |    1 +
 include/trace/events/scmi.h                |   18 +-
 12 files changed, 2292 insertions(+), 140 deletions(-)
 create mode 100644 Documentation/ABI/testing/debugfs-scmi
 create mode 100644 Documentation/ABI/testing/debugfs-scmi-raw
 create mode 100644 drivers/firmware/arm_scmi/raw_mode.c
 create mode 100644 drivers/firmware/arm_scmi/raw_mode.h

-- 
2.34.1

[PATCH v8 01/17] firmware: arm_scmi: Refactor xfer in-flight registration routines

[Cristian Marussi]

Move the whole xfer in-flight registration process out of scmi_xfer_get
and while at that, split the sequence number selection steps from the
in-flight registration procedure itself.

No functional change.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 drivers/firmware/arm_scmi/driver.c | 102 +++++++++++++++++++----------
 1 file changed, 68 insertions(+), 34 deletions(-)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 50267eef10fa..3400bd124a38 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -411,8 +411,6 @@ static int scmi_xfer_token_set(struct scmi_xfers_info *minfo,
 	if (xfer_id != next_token)
 		atomic_add((int)(xfer_id - next_token), &transfer_last_id);
 
-	/* Set in-flight */
-	set_bit(xfer_id, minfo->xfer_alloc_table);
 	xfer->hdr.seq = (u16)xfer_id;
 
 	return 0;
@@ -430,33 +428,77 @@ static inline void scmi_xfer_token_clear(struct scmi_xfers_info *minfo,
 	clear_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
 }
 
+/**
+ * scmi_xfer_inflight_register_unlocked  - Register the xfer as in-flight
+ *
+ * @xfer: The xfer to register
+ * @minfo: Pointer to Tx/Rx Message management info based on channel type
+ *
+ * Note that this helper assumes that the xfer to be registered as in-flight
+ * had been built using an xfer sequence number which still corresponds to a
+ * free slot in the xfer_alloc_table.
+ *
+ * Context: Assumes to be called with @xfer_lock already acquired.
+ */
+static inline void
+scmi_xfer_inflight_register_unlocked(struct scmi_xfer *xfer,
+				     struct scmi_xfers_info *minfo)
+{
+	/* Set in-flight */
+	set_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
+	hash_add(minfo->pending_xfers, &xfer->node, xfer->hdr.seq);
+	xfer->pending = true;
+}
+
+/**
+ * scmi_xfer_pending_set  - Pick a proper sequence number and mark the xfer
+ * as pending in-flight
+ *
+ * @xfer: The xfer to act upon
+ * @minfo: Pointer to Tx/Rx Message management info based on channel type
+ *
+ * Return: 0 on Success or error otherwise
+ */
+static inline int scmi_xfer_pending_set(struct scmi_xfer *xfer,
+					struct scmi_xfers_info *minfo)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&minfo->xfer_lock, flags);
+	/* Set a new monotonic token as the xfer sequence number */
+	ret = scmi_xfer_token_set(minfo, xfer);
+	if (!ret)
+		scmi_xfer_inflight_register_unlocked(xfer, minfo);
+	spin_unlock_irqrestore(&minfo->xfer_lock, flags);
+
+	return ret;
+}
+
 /**
  * scmi_xfer_get() - Allocate one message
  *
  * @handle: Pointer to SCMI entity handle
  * @minfo: Pointer to Tx/Rx Message management info based on channel type
- * @set_pending: If true a monotonic token is picked and the xfer is added to
- *		 the pending hash table.
  *
  * Helper function which is used by various message functions that are
  * exposed to clients of this driver for allocating a message traffic event.
  *
- * Picks an xfer from the free list @free_xfers (if any available) and, if
- * required, sets a monotonically increasing token and stores the inflight xfer
- * into the @pending_xfers hashtable for later retrieval.
+ * Picks an xfer from the free list @free_xfers (if any available) and perform
+ * a basic initialization.
+ *
+ * Note that, at this point, still no sequence number is assigned to the
+ * allocated xfer, nor it is registered as a pending transaction.
  *
  * The successfully initialized xfer is refcounted.
  *
- * Context: Holds @xfer_lock while manipulating @xfer_alloc_table and
- *	    @free_xfers.
+ * Context: Holds @xfer_lock while manipulating @free_xfers.
  *
- * Return: 0 if all went fine, else corresponding error.
+ * Return: An initialized xfer if all went fine, else pointer error.
  */
 static struct scmi_xfer *scmi_xfer_get(const struct scmi_handle *handle,
-				       struct scmi_xfers_info *minfo,
-				       bool set_pending)
+				       struct scmi_xfers_info *minfo)
 {
-	int ret;
 	unsigned long flags;
 	struct scmi_xfer *xfer;
 
@@ -476,25 +518,8 @@ static struct scmi_xfer *scmi_xfer_get(const struct scmi_handle *handle,
 	 */
 	xfer->transfer_id = atomic_inc_return(&transfer_last_id);
 
-	if (set_pending) {
-		/* Pick and set monotonic token */
-		ret = scmi_xfer_token_set(minfo, xfer);
-		if (!ret) {
-			hash_add(minfo->pending_xfers, &xfer->node,
-				 xfer->hdr.seq);
-			xfer->pending = true;
-		} else {
-			dev_err(handle->dev,
-				"Failed to get monotonic token %d\n", ret);
-			hlist_add_head(&xfer->node, &minfo->free_xfers);
-			xfer = ERR_PTR(ret);
-		}
-	}
-
-	if (!IS_ERR(xfer)) {
-		refcount_set(&xfer->users, 1);
-		atomic_set(&xfer->busy, SCMI_XFER_FREE);
-	}
+	refcount_set(&xfer->users, 1);
+	atomic_set(&xfer->busy, SCMI_XFER_FREE);
 	spin_unlock_irqrestore(&minfo->xfer_lock, flags);
 
 	return xfer;
@@ -752,7 +777,7 @@ static void scmi_handle_notification(struct scmi_chan_info *cinfo,
 	ktime_t ts;
 
 	ts = ktime_get_boottime();
-	xfer = scmi_xfer_get(cinfo->handle, minfo, false);
+	xfer = scmi_xfer_get(cinfo->handle, minfo);
 	if (IS_ERR(xfer)) {
 		dev_err(dev, "failed to get free message slot (%ld)\n",
 			PTR_ERR(xfer));
@@ -1143,13 +1168,22 @@ static int xfer_get_init(const struct scmi_protocol_handle *ph,
 	    tx_size > info->desc->max_msg_size)
 		return -ERANGE;
 
-	xfer = scmi_xfer_get(pi->handle, minfo, true);
+	xfer = scmi_xfer_get(pi->handle, minfo);
 	if (IS_ERR(xfer)) {
 		ret = PTR_ERR(xfer);
 		dev_err(dev, "failed to get free message slot(%d)\n", ret);
 		return ret;
 	}
 
+	/* Pick a sequence number and register this xfer as in-flight */
+	ret = scmi_xfer_pending_set(xfer, minfo);
+	if (ret) {
+		dev_err(pi->handle->dev,
+			"Failed to get monotonic token %d\n", ret);
+		__scmi_xfer_put(minfo, xfer);
+		return ret;
+	}
+
 	xfer->tx.len = tx_size;
 	xfer->rx.len = rx_size ? : info->desc->max_msg_size;
 	xfer->hdr.type = MSG_TYPE_COMMAND;
-- 
2.34.1

[PATCH v8 02/17] firmware: arm_scmi: Refactor polling helpers

[Cristian Marussi]

Refactor polling helpers to receive scmi_desc directly as a parameter and
move all of them to common.h.

No functional change.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 drivers/firmware/arm_scmi/common.h | 18 ++++++++++++++++
 drivers/firmware/arm_scmi/driver.c | 34 ++++++++----------------------
 2 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 80f63fc8ca14..f785f0ff2090 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -211,6 +211,24 @@ struct scmi_desc {
 	const bool atomic_enabled;
 };
 
+static inline bool is_polling_required(struct scmi_chan_info *cinfo,
+				       const struct scmi_desc *desc)
+{
+	return cinfo->no_completion_irq || desc->force_polling;
+}
+
+static inline bool is_transport_polling_capable(const struct scmi_desc *desc)
+{
+	return desc->ops->poll_done || desc->sync_cmds_completed_on_ret;
+}
+
+static inline bool is_polling_enabled(struct scmi_chan_info *cinfo,
+				      const struct scmi_desc *desc)
+{
+	return is_polling_required(cinfo, desc) &&
+		is_transport_polling_capable(desc);
+}
+
 #ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX
 extern const struct scmi_desc scmi_mailbox_desc;
 #endif
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 3400bd124a38..d7f21e81bd11 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -748,25 +748,6 @@ static inline void scmi_clear_channel(struct scmi_info *info,
 		info->desc->ops->clear_channel(cinfo);
 }
 
-static inline bool is_polling_required(struct scmi_chan_info *cinfo,
-				       struct scmi_info *info)
-{
-	return cinfo->no_completion_irq || info->desc->force_polling;
-}
-
-static inline bool is_transport_polling_capable(struct scmi_info *info)
-{
-	return info->desc->ops->poll_done ||
-		info->desc->sync_cmds_completed_on_ret;
-}
-
-static inline bool is_polling_enabled(struct scmi_chan_info *cinfo,
-				      struct scmi_info *info)
-{
-	return is_polling_required(cinfo, info) &&
-		is_transport_polling_capable(info);
-}
-
 static void scmi_handle_notification(struct scmi_chan_info *cinfo,
 				     u32 msg_hdr, void *priv)
 {
@@ -1009,7 +990,8 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
 	struct scmi_chan_info *cinfo;
 
 	/* Check for polling request on custom command xfers at first */
-	if (xfer->hdr.poll_completion && !is_transport_polling_capable(info)) {
+	if (xfer->hdr.poll_completion &&
+	    !is_transport_polling_capable(info->desc)) {
 		dev_warn_once(dev,
 			      "Polling mode is not supported by transport.\n");
 		return -EINVAL;
@@ -1020,7 +1002,7 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
 		return -EINVAL;
 
 	/* True ONLY if also supported by transport. */
-	if (is_polling_enabled(cinfo, info))
+	if (is_polling_enabled(cinfo, info->desc))
 		xfer->hdr.poll_completion = true;
 
 	/*
@@ -1956,7 +1938,8 @@ static bool scmi_is_transport_atomic(const struct scmi_handle *handle,
 	bool ret;
 	struct scmi_info *info = handle_to_scmi_info(handle);
 
-	ret = info->desc->atomic_enabled && is_transport_polling_capable(info);
+	ret = info->desc->atomic_enabled &&
+		is_transport_polling_capable(info->desc);
 	if (ret && atomic_threshold)
 		*atomic_threshold = info->atomic_threshold;
 
@@ -2180,8 +2163,8 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
 		return ret;
 	}
 
-	if (tx && is_polling_required(cinfo, info)) {
-		if (is_transport_polling_capable(info))
+	if (tx && is_polling_required(cinfo, info->desc)) {
+		if (is_transport_polling_capable(info->desc))
 			dev_info(&tdev->dev,
 				 "Enabled polling mode TX channel - prot_id:%d\n",
 				 prot_id);
@@ -2443,7 +2426,8 @@ static int scmi_probe(struct platform_device *pdev)
 	if (scmi_notification_init(handle))
 		dev_err(dev, "SCMI Notifications NOT available.\n");
 
-	if (info->desc->atomic_enabled && !is_transport_polling_capable(info))
+	if (info->desc->atomic_enabled &&
+	    !is_transport_polling_capable(info->desc))
 		dev_err(dev,
 			"Transport is not polling capable. Atomic mode not supported.\n");
 
-- 
2.34.1

[PATCH v8 03/17] firmware: arm_scmi: Refactor scmi_wait_for_message_response

[Cristian Marussi]

Refactor scmi_wait_for_message_response() to use a internal helper to
carry out its main duties; while doing that  make it accept directly an
scmi_desc parameter to interact with the configured transport.

No functional change.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 drivers/firmware/arm_scmi/driver.c | 57 +++++++++++++++++-------------
 1 file changed, 33 insertions(+), 24 deletions(-)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index d7f21e81bd11..ce204a77c7f3 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -891,36 +891,18 @@ static bool scmi_xfer_done_no_timeout(struct scmi_chan_info *cinfo,
 	       ktime_after(ktime_get(), stop);
 }
 
-/**
- * scmi_wait_for_message_response  - An helper to group all the possible ways of
- * waiting for a synchronous message response.
- *
- * @cinfo: SCMI channel info
- * @xfer: Reference to the transfer being waited for.
- *
- * Chooses waiting strategy (sleep-waiting vs busy-waiting) depending on
- * configuration flags like xfer->hdr.poll_completion.
- *
- * Return: 0 on Success, error otherwise.
- */
-static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo,
-					  struct scmi_xfer *xfer)
+static int scmi_wait_for_reply(struct device *dev, const struct scmi_desc *desc,
+			       struct scmi_chan_info *cinfo,
+			       struct scmi_xfer *xfer, unsigned int timeout_ms)
 {
-	struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
-	struct device *dev = info->dev;
-	int ret = 0, timeout_ms = info->desc->max_rx_timeout_ms;
-
-	trace_scmi_xfer_response_wait(xfer->transfer_id, xfer->hdr.id,
-				      xfer->hdr.protocol_id, xfer->hdr.seq,
-				      timeout_ms,
-				      xfer->hdr.poll_completion);
+	int ret = 0;
 
 	if (xfer->hdr.poll_completion) {
 		/*
 		 * Real polling is needed only if transport has NOT declared
 		 * itself to support synchronous commands replies.
 		 */
-		if (!info->desc->sync_cmds_completed_on_ret) {
+		if (!desc->sync_cmds_completed_on_ret) {
 			/*
 			 * Poll on xfer using transport provided .poll_done();
 			 * assumes no completion interrupt was available.
@@ -946,7 +928,7 @@ static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo,
 			 */
 			spin_lock_irqsave(&xfer->lock, flags);
 			if (xfer->state == SCMI_XFER_SENT_OK) {
-				info->desc->ops->fetch_response(cinfo, xfer);
+				desc->ops->fetch_response(cinfo, xfer);
 				xfer->state = SCMI_XFER_RESP_OK;
 			}
 			spin_unlock_irqrestore(&xfer->lock, flags);
@@ -970,6 +952,33 @@ static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo,
 	return ret;
 }
 
+/**
+ * scmi_wait_for_message_response  - An helper to group all the possible ways of
+ * waiting for a synchronous message response.
+ *
+ * @cinfo: SCMI channel info
+ * @xfer: Reference to the transfer being waited for.
+ *
+ * Chooses waiting strategy (sleep-waiting vs busy-waiting) depending on
+ * configuration flags like xfer->hdr.poll_completion.
+ *
+ * Return: 0 on Success, error otherwise.
+ */
+static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo,
+					  struct scmi_xfer *xfer)
+{
+	struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
+	struct device *dev = info->dev;
+
+	trace_scmi_xfer_response_wait(xfer->transfer_id, xfer->hdr.id,
+				      xfer->hdr.protocol_id, xfer->hdr.seq,
+				      info->desc->max_rx_timeout_ms,
+				      xfer->hdr.poll_completion);
+
+	return scmi_wait_for_reply(dev, info->desc, cinfo, xfer,
+				   info->desc->max_rx_timeout_ms);
+}
+
 /**
  * do_xfer() - Do one transfer
  *
-- 
2.34.1

[PATCH v8 04/17] firmware: arm_scmi: Add flags field to xfer

[Cristian Marussi]

Add a flags field to xfer and define a flagbit and related macro to easily
identify xfers originated from Raw transmissions.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v5 --> v6
- convert is_raw boolean to a bitflag
---
 drivers/firmware/arm_scmi/protocols.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/firmware/arm_scmi/protocols.h b/drivers/firmware/arm_scmi/protocols.h
index 2f3bf691db7c..b5941beb8b03 100644
--- a/drivers/firmware/arm_scmi/protocols.h
+++ b/drivers/firmware/arm_scmi/protocols.h
@@ -115,6 +115,7 @@ struct scmi_msg_hdr {
  *	    - SCMI_XFER_SENT_OK -> SCMI_XFER_RESP_OK [ -> SCMI_XFER_DRESP_OK ]
  *	    - SCMI_XFER_SENT_OK -> SCMI_XFER_DRESP_OK
  *	      (Missing synchronous response is assumed OK and ignored)
+ * @flags: Optional flags associated to this xfer.
  * @lock: A spinlock to protect state and busy fields.
  * @priv: A pointer for transport private usage.
  */
@@ -135,6 +136,9 @@ struct scmi_xfer {
 #define SCMI_XFER_RESP_OK	1
 #define SCMI_XFER_DRESP_OK	2
 	int state;
+#define SCMI_XFER_FLAG_IS_RAW	BIT(0)
+#define SCMI_XFER_IS_RAW(x)	((x)->flags & SCMI_XFER_FLAG_IS_RAW)
+	int flags;
 	/* A lock to protect state and busy fields */
 	spinlock_t lock;
 	void *priv;
-- 
2.34.1

[PATCH v8 05/17] firmware: arm_scmi: Add xfer Raw helpers

[Cristian Marussi]

Add a few SCMI helpers useful to implement SCMI Raw access support.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v5 --> v6
- handling is_raw as a bitflag
v4 --> v5
- add handling of xfer->is_raw flag
v3 --> v4
- add scmi_xfer_raw_wait_for_response helper
- fixed typos in comments
v2 --> v3
- allow for DT-unknown protocols to get a channel
v1 --> v2
- added scmi_xfer_raw_channel_get
---
 drivers/firmware/arm_scmi/common.h |  12 +++
 drivers/firmware/arm_scmi/driver.c | 147 +++++++++++++++++++++++++++++
 2 files changed, 159 insertions(+)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index f785f0ff2090..e9aa1cfef90d 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -229,6 +229,18 @@ static inline bool is_polling_enabled(struct scmi_chan_info *cinfo,
 		is_transport_polling_capable(desc);
 }
 
+void scmi_xfer_raw_put(const struct scmi_handle *handle,
+		       struct scmi_xfer *xfer);
+struct scmi_xfer *scmi_xfer_raw_get(const struct scmi_handle *handle);
+struct scmi_chan_info *
+scmi_xfer_raw_channel_get(const struct scmi_handle *handle, u8 protocol_id);
+
+int scmi_xfer_raw_inflight_register(const struct scmi_handle *handle,
+				    struct scmi_xfer *xfer);
+
+int scmi_xfer_raw_wait_for_message_response(struct scmi_chan_info *cinfo,
+					    struct scmi_xfer *xfer,
+					    unsigned int timeout_ms);
 #ifdef CONFIG_ARM_SCMI_TRANSPORT_MAILBOX
 extern const struct scmi_desc scmi_mailbox_desc;
 #endif
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index ce204a77c7f3..67072699b029 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -450,6 +450,53 @@ scmi_xfer_inflight_register_unlocked(struct scmi_xfer *xfer,
 	xfer->pending = true;
 }
 
+/**
+ * scmi_xfer_inflight_register  - Try to register an xfer as in-flight
+ *
+ * @xfer: The xfer to register
+ * @minfo: Pointer to Tx/Rx Message management info based on channel type
+ *
+ * Note that this helper does NOT assume anything about the sequence number
+ * that was baked into the provided xfer, so it checks at first if it can
+ * be mapped to a free slot and fails with an error if another xfer with the
+ * same sequence number is currently still registered as in-flight.
+ *
+ * Return: 0 on Success or -EBUSY if sequence number embedded in the xfer
+ *	   could not rbe mapped to a free slot in the xfer_alloc_table.
+ */
+static int scmi_xfer_inflight_register(struct scmi_xfer *xfer,
+				       struct scmi_xfers_info *minfo)
+{
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&minfo->xfer_lock, flags);
+	if (!test_bit(xfer->hdr.seq, minfo->xfer_alloc_table))
+		scmi_xfer_inflight_register_unlocked(xfer, minfo);
+	else
+		ret = -EBUSY;
+	spin_unlock_irqrestore(&minfo->xfer_lock, flags);
+
+	return ret;
+}
+
+/**
+ * scmi_xfer_raw_inflight_register  - An helper to register the given xfer as in
+ * flight on the TX channel, if possible.
+ *
+ * @handle: Pointer to SCMI entity handle
+ * @xfer: The xfer to register
+ *
+ * Return: 0 on Success, error otherwise
+ */
+int scmi_xfer_raw_inflight_register(const struct scmi_handle *handle,
+				    struct scmi_xfer *xfer)
+{
+	struct scmi_info *info = handle_to_scmi_info(handle);
+
+	return scmi_xfer_inflight_register(xfer, &info->tx_minfo);
+}
+
 /**
  * scmi_xfer_pending_set  - Pick a proper sequence number and mark the xfer
  * as pending in-flight
@@ -525,6 +572,63 @@ static struct scmi_xfer *scmi_xfer_get(const struct scmi_handle *handle,
 	return xfer;
 }
 
+/**
+ * scmi_xfer_raw_get  - Helper to get a bare free xfer from the TX channel
+ *
+ * @handle: Pointer to SCMI entity handle
+ *
+ * Note that xfer is taken from the TX channel structures.
+ *
+ * Return: A valid xfer on Success, or an error-pointer otherwise
+ */
+struct scmi_xfer *scmi_xfer_raw_get(const struct scmi_handle *handle)
+{
+	struct scmi_xfer *xfer;
+	struct scmi_info *info = handle_to_scmi_info(handle);
+
+	xfer = scmi_xfer_get(handle, &info->tx_minfo);
+	if (!IS_ERR(xfer))
+		xfer->flags |= SCMI_XFER_FLAG_IS_RAW;
+
+	return xfer;
+}
+
+/**
+ * scmi_xfer_raw_channel_get  - Helper to get a reference to the proper channel
+ * to use for a specific protocol_id Raw transaction.
+ *
+ * @handle: Pointer to SCMI entity handle
+ * @protocol_id: Identifier of the protocol
+ *
+ * Note that in a regular SCMI stack, usually, a protocol has to be defined in
+ * the DT to have an associated channel and be usable; but in Raw mode any
+ * protocol in range is allowed, re-using the Base channel, so as to enable
+ * fuzzing on any protocol without the need of a fully compiled DT.
+ *
+ * Return: A reference to the channel to use, or an ERR_PTR
+ */
+struct scmi_chan_info *
+scmi_xfer_raw_channel_get(const struct scmi_handle *handle, u8 protocol_id)
+{
+	struct scmi_chan_info *cinfo;
+	struct scmi_info *info = handle_to_scmi_info(handle);
+
+	cinfo = idr_find(&info->tx_idr, protocol_id);
+	if (!cinfo) {
+		if (protocol_id == SCMI_PROTOCOL_BASE)
+			return ERR_PTR(-EINVAL);
+		/* Use Base channel for protocols not defined for DT */
+		cinfo = idr_find(&info->tx_idr, SCMI_PROTOCOL_BASE);
+		if (!cinfo)
+			return ERR_PTR(-EINVAL);
+		dev_warn_once(handle->dev,
+			      "Using Base channel for protocol 0x%X\n",
+			      protocol_id);
+	}
+
+	return cinfo;
+}
+
 /**
  * __scmi_xfer_put() - Release a message
  *
@@ -553,6 +657,23 @@ __scmi_xfer_put(struct scmi_xfers_info *minfo, struct scmi_xfer *xfer)
 	spin_unlock_irqrestore(&minfo->xfer_lock, flags);
 }
 
+/**
+ * scmi_xfer_raw_put  - Release an xfer that was taken by @scmi_xfer_raw_get
+ *
+ * @handle: Pointer to SCMI entity handle
+ * @xfer: A reference to the xfer to put
+ *
+ * Note that as with other xfer_put() handlers the xfer is really effectively
+ * released only if there are no more users on the system.
+ */
+void scmi_xfer_raw_put(const struct scmi_handle *handle, struct scmi_xfer *xfer)
+{
+	struct scmi_info *info = handle_to_scmi_info(handle);
+
+	xfer->flags &= ~SCMI_XFER_FLAG_IS_RAW;
+	return __scmi_xfer_put(&info->tx_minfo, xfer);
+}
+
 /**
  * scmi_xfer_lookup_unlocked  -  Helper to lookup an xfer_id
  *
@@ -979,6 +1100,32 @@ static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo,
 				   info->desc->max_rx_timeout_ms);
 }
 
+/**
+ * scmi_xfer_raw_wait_for_message_response  - An helper to wait for a message
+ * reply to an xfer raw request on a specific channel for the required timeout.
+ *
+ * @cinfo: SCMI channel info
+ * @xfer: Reference to the transfer being waited for.
+ * @timeout_ms: The maximum timeout in milliseconds
+ *
+ * Return: 0 on Success, error otherwise.
+ */
+int scmi_xfer_raw_wait_for_message_response(struct scmi_chan_info *cinfo,
+					    struct scmi_xfer *xfer,
+					    unsigned int timeout_ms)
+{
+	int ret;
+	struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
+	struct device *dev = info->dev;
+
+	ret = scmi_wait_for_reply(dev, info->desc, cinfo, xfer, timeout_ms);
+	if (ret)
+		dev_dbg(dev, "timed out in RAW response - HDR:%08X\n",
+			pack_scmi_header(&xfer->hdr));
+
+	return ret;
+}
+
 /**
  * do_xfer() - Do one transfer
  *
-- 
2.34.1

[PATCH v8 06/17] firmware: arm_scmi: Move errors defs and code to common.h

[Cristian Marussi]

Move SCMI error codes definitions and helper to the common.h header
together with the delayed response timeout define.

No functional change.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 drivers/firmware/arm_scmi/common.h | 40 ++++++++++++++++++++++++++++++
 drivers/firmware/arm_scmi/driver.c | 40 ------------------------------
 2 files changed, 40 insertions(+), 40 deletions(-)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index e9aa1cfef90d..049607280ea5 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -27,6 +27,46 @@
 #include "protocols.h"
 #include "notify.h"
 
+#define SCMI_MAX_RESPONSE_TIMEOUT	(2 * MSEC_PER_SEC)
+
+enum scmi_error_codes {
+	SCMI_SUCCESS = 0,	/* Success */
+	SCMI_ERR_SUPPORT = -1,	/* Not supported */
+	SCMI_ERR_PARAMS = -2,	/* Invalid Parameters */
+	SCMI_ERR_ACCESS = -3,	/* Invalid access/permission denied */
+	SCMI_ERR_ENTRY = -4,	/* Not found */
+	SCMI_ERR_RANGE = -5,	/* Value out of range */
+	SCMI_ERR_BUSY = -6,	/* Device busy */
+	SCMI_ERR_COMMS = -7,	/* Communication Error */
+	SCMI_ERR_GENERIC = -8,	/* Generic Error */
+	SCMI_ERR_HARDWARE = -9,	/* Hardware Error */
+	SCMI_ERR_PROTOCOL = -10,/* Protocol Error */
+};
+
+static const int scmi_linux_errmap[] = {
+	/* better than switch case as long as return value is continuous */
+	0,			/* SCMI_SUCCESS */
+	-EOPNOTSUPP,		/* SCMI_ERR_SUPPORT */
+	-EINVAL,		/* SCMI_ERR_PARAM */
+	-EACCES,		/* SCMI_ERR_ACCESS */
+	-ENOENT,		/* SCMI_ERR_ENTRY */
+	-ERANGE,		/* SCMI_ERR_RANGE */
+	-EBUSY,			/* SCMI_ERR_BUSY */
+	-ECOMM,			/* SCMI_ERR_COMMS */
+	-EIO,			/* SCMI_ERR_GENERIC */
+	-EREMOTEIO,		/* SCMI_ERR_HARDWARE */
+	-EPROTO,		/* SCMI_ERR_PROTOCOL */
+};
+
+static inline int scmi_to_linux_errno(int errno)
+{
+	int err_idx = -errno;
+
+	if (err_idx >= SCMI_SUCCESS && err_idx < ARRAY_SIZE(scmi_linux_errmap))
+		return scmi_linux_errmap[err_idx];
+	return -EIO;
+}
+
 #define MSG_ID_MASK		GENMASK(7, 0)
 #define MSG_XTRACT_ID(hdr)	FIELD_GET(MSG_ID_MASK, (hdr))
 #define MSG_TYPE_MASK		GENMASK(9, 8)
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 67072699b029..fefa01dbf9ee 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -39,20 +39,6 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/scmi.h>
 
-enum scmi_error_codes {
-	SCMI_SUCCESS = 0,	/* Success */
-	SCMI_ERR_SUPPORT = -1,	/* Not supported */
-	SCMI_ERR_PARAMS = -2,	/* Invalid Parameters */
-	SCMI_ERR_ACCESS = -3,	/* Invalid access/permission denied */
-	SCMI_ERR_ENTRY = -4,	/* Not found */
-	SCMI_ERR_RANGE = -5,	/* Value out of range */
-	SCMI_ERR_BUSY = -6,	/* Device busy */
-	SCMI_ERR_COMMS = -7,	/* Communication Error */
-	SCMI_ERR_GENERIC = -8,	/* Generic Error */
-	SCMI_ERR_HARDWARE = -9,	/* Hardware Error */
-	SCMI_ERR_PROTOCOL = -10,/* Protocol Error */
-};
-
 static DEFINE_IDR(scmi_protocols);
 static DEFINE_SPINLOCK(protocol_lock);
 
@@ -172,30 +158,6 @@ struct scmi_info {
 #define bus_nb_to_scmi_info(nb)	container_of(nb, struct scmi_info, bus_nb)
 #define req_nb_to_scmi_info(nb)	container_of(nb, struct scmi_info, dev_req_nb)
 
-static const int scmi_linux_errmap[] = {
-	/* better than switch case as long as return value is continuous */
-	0,			/* SCMI_SUCCESS */
-	-EOPNOTSUPP,		/* SCMI_ERR_SUPPORT */
-	-EINVAL,		/* SCMI_ERR_PARAM */
-	-EACCES,		/* SCMI_ERR_ACCESS */
-	-ENOENT,		/* SCMI_ERR_ENTRY */
-	-ERANGE,		/* SCMI_ERR_RANGE */
-	-EBUSY,			/* SCMI_ERR_BUSY */
-	-ECOMM,			/* SCMI_ERR_COMMS */
-	-EIO,			/* SCMI_ERR_GENERIC */
-	-EREMOTEIO,		/* SCMI_ERR_HARDWARE */
-	-EPROTO,		/* SCMI_ERR_PROTOCOL */
-};
-
-static inline int scmi_to_linux_errno(int errno)
-{
-	int err_idx = -errno;
-
-	if (err_idx >= SCMI_SUCCESS && err_idx < ARRAY_SIZE(scmi_linux_errmap))
-		return scmi_linux_errmap[err_idx];
-	return -EIO;
-}
-
 static const struct scmi_protocol *scmi_protocol_get(int protocol_id)
 {
 	const struct scmi_protocol *proto;
@@ -1217,8 +1179,6 @@ static void reset_rx_to_maxsz(const struct scmi_protocol_handle *ph,
 	xfer->rx.len = info->desc->max_msg_size;
 }
 
-#define SCMI_MAX_RESPONSE_TIMEOUT	(2 * MSEC_PER_SEC)
-
 /**
  * do_xfer_with_response() - Do one transfer and wait until the delayed
  *	response is received
-- 
2.34.1

[PATCH v8 07/17] firmware: arm_scmi: Add internal platform/channel IDs

[Cristian Marussi]

Add a couple of unique identifiers to channel and platform instance
descriptors in order to emit more descriptive message dump traces.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 drivers/firmware/arm_scmi/common.h |  3 +++
 drivers/firmware/arm_scmi/driver.c | 17 +++++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index 049607280ea5..bf3883f169e3 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -157,6 +157,8 @@ void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id);
 /**
  * struct scmi_chan_info - Structure representing a SCMI channel information
  *
+ * @id: An identifier for this channel: this matches the protocol number
+ *      used to initialize this channel
  * @dev: Reference to device in the SCMI hierarchy corresponding to this
  *	 channel
  * @rx_timeout_ms: The configured RX timeout in milliseconds.
@@ -168,6 +170,7 @@ void scmi_protocol_release(const struct scmi_handle *handle, u8 protocol_id);
  * @transport_info: Transport layer related information
  */
 struct scmi_chan_info {
+	int id;
 	struct device *dev;
 	unsigned int rx_timeout_ms;
 	struct scmi_handle *handle;
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index fefa01dbf9ee..af34324e923b 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -39,6 +39,8 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/scmi.h>
 
+static DEFINE_IDA(scmi_id);
+
 static DEFINE_IDR(scmi_protocols);
 static DEFINE_SPINLOCK(protocol_lock);
 
@@ -98,6 +100,7 @@ struct scmi_protocol_instance {
 /**
  * struct scmi_info - Structure representing a SCMI instance
  *
+ * @id: A sequence number starting from zero identifying this instance
  * @dev: Device pointer
  * @desc: SoC description for this instance
  * @version: SCMI revision information containing protocol version,
@@ -131,6 +134,7 @@ struct scmi_protocol_instance {
  * @devreq_mtx: A mutex to serialize device creation for this SCMI instance
  */
 struct scmi_info {
+	int id;
 	struct device *dev;
 	const struct scmi_desc *desc;
 	struct scmi_revision_info version;
@@ -2270,6 +2274,7 @@ static int scmi_chan_setup(struct scmi_info *info, struct device_node *of_node,
 	}
 	of_node_get(of_node);
 
+	cinfo->id = prot_id;
 	cinfo->dev = &tdev->dev;
 	ret = info->desc->ops->chan_setup(cinfo, info->dev, tx);
 	if (ret) {
@@ -2486,6 +2491,10 @@ static int scmi_probe(struct platform_device *pdev)
 	if (!info)
 		return -ENOMEM;
 
+	info->id = ida_alloc_min(&scmi_id, 0, GFP_KERNEL);
+	if (info->id < 0)
+		return info->id;
+
 	info->dev = dev;
 	info->desc = desc;
 	info->bus_nb.notifier_call = scmi_bus_notifier;
@@ -2518,13 +2527,13 @@ static int scmi_probe(struct platform_device *pdev)
 	if (desc->ops->link_supplier) {
 		ret = desc->ops->link_supplier(dev);
 		if (ret)
-			return ret;
+			goto clear_ida;
 	}
 
 	/* Setup all channels described in the DT at first */
 	ret = scmi_channels_setup(info);
 	if (ret)
-		return ret;
+		goto clear_ida;
 
 	ret = bus_register_notifier(&scmi_bus_type, &info->bus_nb);
 	if (ret)
@@ -2604,6 +2613,8 @@ static int scmi_probe(struct platform_device *pdev)
 	bus_unregister_notifier(&scmi_bus_type, &info->bus_nb);
 clear_txrx_setup:
 	scmi_cleanup_txrx_channels(info);
+clear_ida:
+	ida_free(&scmi_id, info->id);
 	return ret;
 }
 
@@ -2637,6 +2648,8 @@ static int scmi_remove(struct platform_device *pdev)
 	/* Safe to free channels since no more users */
 	scmi_cleanup_txrx_channels(info);
 
+	ida_free(&scmi_id, info->id);
+
 	return 0;
 }
 
-- 
2.34.1

[PATCH v8 08/17] include: trace: Add platform and channel instance references

[Cristian Marussi]

Add channel and platform instance indentifier to SCMI message dump traces
in order to easily associate message flows to specific transport channels.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 drivers/firmware/arm_scmi/driver.c | 20 ++++++++++++--------
 include/trace/events/scmi.h        | 18 ++++++++++++------
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index af34324e923b..c765d0c51dc5 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -860,9 +860,9 @@ static void scmi_handle_notification(struct scmi_chan_info *cinfo,
 	info->desc->ops->fetch_notification(cinfo, info->desc->max_msg_size,
 					    xfer);
 
-	trace_scmi_msg_dump(xfer->hdr.protocol_id, xfer->hdr.id, "NOTI",
-			    xfer->hdr.seq, xfer->hdr.status,
-			    xfer->rx.buf, xfer->rx.len);
+	trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
+			    xfer->hdr.id, "NOTI", xfer->hdr.seq,
+			    xfer->hdr.status, xfer->rx.buf, xfer->rx.len);
 
 	scmi_notify(cinfo->handle, xfer->hdr.protocol_id,
 		    xfer->hdr.id, xfer->rx.buf, xfer->rx.len, ts);
@@ -898,7 +898,8 @@ static void scmi_handle_response(struct scmi_chan_info *cinfo,
 		smp_store_mb(xfer->priv, priv);
 	info->desc->ops->fetch_response(cinfo, xfer);
 
-	trace_scmi_msg_dump(xfer->hdr.protocol_id, xfer->hdr.id,
+	trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
+			    xfer->hdr.id,
 			    xfer->hdr.type == MSG_TYPE_DELAYED_RESP ?
 			    "DLYD" : "RESP",
 			    xfer->hdr.seq, xfer->hdr.status,
@@ -1008,6 +1009,8 @@ static int scmi_wait_for_reply(struct device *dev, const struct scmi_desc *desc,
 
 		if (!ret) {
 			unsigned long flags;
+			struct scmi_info *info =
+				handle_to_scmi_info(cinfo->handle);
 
 			/*
 			 * Do not fetch_response if an out-of-order delayed
@@ -1021,7 +1024,8 @@ static int scmi_wait_for_reply(struct device *dev, const struct scmi_desc *desc,
 			spin_unlock_irqrestore(&xfer->lock, flags);
 
 			/* Trace polled replies. */
-			trace_scmi_msg_dump(xfer->hdr.protocol_id, xfer->hdr.id,
+			trace_scmi_msg_dump(info->id, cinfo->id,
+					    xfer->hdr.protocol_id, xfer->hdr.id,
 					    "RESP",
 					    xfer->hdr.seq, xfer->hdr.status,
 					    xfer->rx.buf, xfer->rx.len);
@@ -1157,9 +1161,9 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
 		return ret;
 	}
 
-	trace_scmi_msg_dump(xfer->hdr.protocol_id, xfer->hdr.id, "CMND",
-			    xfer->hdr.seq, xfer->hdr.status,
-			    xfer->tx.buf, xfer->tx.len);
+	trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
+			    xfer->hdr.id, "CMND", xfer->hdr.seq,
+			    xfer->hdr.status, xfer->tx.buf, xfer->tx.len);
 
 	ret = scmi_wait_for_message_response(cinfo, xfer);
 	if (!ret && xfer->hdr.status)
diff --git a/include/trace/events/scmi.h b/include/trace/events/scmi.h
index f160d68f961d..422c1ad9484d 100644
--- a/include/trace/events/scmi.h
+++ b/include/trace/events/scmi.h
@@ -139,11 +139,15 @@ TRACE_EVENT(scmi_rx_done,
 );
 
 TRACE_EVENT(scmi_msg_dump,
-	TP_PROTO(u8 protocol_id, u8 msg_id, unsigned char *tag, u16 seq,
-		 int status, void *buf, size_t len),
-	TP_ARGS(protocol_id, msg_id, tag, seq, status, buf, len),
+	TP_PROTO(int id, u8 channel_id, u8 protocol_id, u8 msg_id,
+		 unsigned char *tag, u16 seq, int status,
+		 void *buf, size_t len),
+	TP_ARGS(id, channel_id, protocol_id, msg_id, tag, seq, status,
+		buf, len),
 
 	TP_STRUCT__entry(
+		__field(int, id)
+		__field(u8, channel_id)
 		__field(u8, protocol_id)
 		__field(u8, msg_id)
 		__array(char, tag, 5)
@@ -154,6 +158,8 @@ TRACE_EVENT(scmi_msg_dump,
 	),
 
 	TP_fast_assign(
+		__entry->id = id;
+		__entry->channel_id = channel_id;
 		__entry->protocol_id = protocol_id;
 		__entry->msg_id = msg_id;
 		strscpy(__entry->tag, tag, 5);
@@ -163,9 +169,9 @@ TRACE_EVENT(scmi_msg_dump,
 		memcpy(__get_dynamic_array(cmd), buf, __entry->len);
 	),
 
-	TP_printk("pt=%02X t=%s msg_id=%02X seq=%04X s=%d pyld=%s",
-		  __entry->protocol_id, __entry->tag, __entry->msg_id,
-		  __entry->seq, __entry->status,
+	TP_printk("id=%d ch=%02X pt=%02X t=%s msg_id=%02X seq=%04X s=%d pyld=%s",
+		  __entry->id, __entry->channel_id, __entry->protocol_id,
+		  __entry->tag, __entry->msg_id, __entry->seq, __entry->status,
 		__print_hex_str(__get_dynamic_array(cmd), __entry->len))
 );
 #endif /* _TRACE_SCMI_H */
-- 
2.34.1

[PATCH v8 09/17] debugfs: Export debugfs_create_str symbol

[Cristian Marussi]

Needed by SCMI Raw mode support when compiled as a loadable module.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
Used by the following patch in this series:

"firmware: arm_scmi: Populate a common SCMI debugsfs root"

SCMI stack can be configured as module so export is needed.
---
 fs/debugfs/file.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index b54f470e0d03..1f971c880dde 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -899,6 +899,7 @@ ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(debugfs_create_str);
 
 static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf,
 				      size_t count, loff_t *ppos)
-- 
2.34.1

[PATCH v8 10/17] firmware: arm_scmi: Populate a common SCMI debugsfs root

[Cristian Marussi]

Create a common SCMI debugfs root-directory and populate it with some
common SCMI data for each discovered SCMI platform instance if SCMI debugfs
is needed by any configured SCMI facility.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v7 --> v8
 - Fixed scmi_debugfs_common_setup return values
Reported-by: Dan Carpenter <error27@gmail.com>
v6 --> v7
 - Fixed uninitialized value in scmi_debugfs_common_setup
   as reported by:
---
 drivers/firmware/arm_scmi/Kconfig  |   7 ++
 drivers/firmware/arm_scmi/driver.c | 120 +++++++++++++++++++++++++++++
 2 files changed, 127 insertions(+)

diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig
index a14f65444b35..f36f89a22740 100644
--- a/drivers/firmware/arm_scmi/Kconfig
+++ b/drivers/firmware/arm_scmi/Kconfig
@@ -23,6 +23,13 @@ config ARM_SCMI_PROTOCOL
 
 if ARM_SCMI_PROTOCOL
 
+config ARM_SCMI_NEED_DEBUGFS
+	bool
+	help
+	  This declares whether at least one SCMI facility is configured
+	  which needs debugfs support. When selected causess the creation
+	  of a common SCMI debugfs root directory.
+
 config ARM_SCMI_HAVE_TRANSPORT
 	bool
 	help
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index c765d0c51dc5..5d5defd92403 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -17,6 +17,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/bitmap.h>
+#include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/export.h>
 #include <linux/idr.h>
@@ -51,6 +52,8 @@ static DEFINE_MUTEX(scmi_list_mutex);
 /* Track the unique id for the transfers for debug & profiling purpose */
 static atomic_t transfer_last_id;
 
+static struct dentry *scmi_top_dentry;
+
 /**
  * struct scmi_xfers_info - Structure to manage transfer information
  *
@@ -97,6 +100,20 @@ struct scmi_protocol_instance {
 
 #define ph_to_pi(h)	container_of(h, struct scmi_protocol_instance, ph)
 
+/**
+ * struct scmi_debug_info  - Debug common info
+ * @top_dentry: A reference to the top debugfs dentry
+ * @name: Name of this SCMI instance
+ * @type: Type of this SCMI instance
+ * @is_atomic: Flag to state if the transport of this instance is atomic
+ */
+struct scmi_debug_info {
+	struct dentry *top_dentry;
+	const char *name;
+	const char *type;
+	bool is_atomic;
+};
+
 /**
  * struct scmi_info - Structure representing a SCMI instance
  *
@@ -132,6 +149,7 @@ struct scmi_protocol_instance {
  * @dev_req_nb: A notifier to listen for device request/unrequest on the scmi
  *		bus
  * @devreq_mtx: A mutex to serialize device creation for this SCMI instance
+ * @dbg: A pointer to debugfs related data (if any)
  */
 struct scmi_info {
 	int id;
@@ -156,6 +174,7 @@ struct scmi_info {
 	struct notifier_block dev_req_nb;
 	/* Serialize device creation process for this instance */
 	struct mutex devreq_mtx;
+	struct scmi_debug_info *dbg;
 };
 
 #define handle_to_scmi_info(h)	container_of(h, struct scmi_info, handle)
@@ -2478,6 +2497,83 @@ static int scmi_device_request_notifier(struct notifier_block *nb,
 	return NOTIFY_OK;
 }
 
+static void scmi_debugfs_common_cleanup(void *d)
+{
+	struct scmi_debug_info *dbg = d;
+
+	if (!dbg)
+		return;
+
+	debugfs_remove_recursive(dbg->top_dentry);
+	kfree(dbg->name);
+	kfree(dbg->type);
+}
+
+static struct scmi_debug_info *scmi_debugfs_common_setup(struct scmi_info *info)
+{
+	char top_dir[16];
+	struct dentry *trans, *top_dentry;
+	struct scmi_debug_info *dbg;
+	const char *c_ptr = NULL;
+
+	dbg = devm_kzalloc(info->dev, sizeof(*dbg), GFP_KERNEL);
+	if (!dbg)
+		return NULL;
+
+	dbg->name = kstrdup(of_node_full_name(info->dev->of_node), GFP_KERNEL);
+	if (!dbg->name) {
+		devm_kfree(info->dev, dbg);
+		return NULL;
+	}
+
+	of_property_read_string(info->dev->of_node, "compatible", &c_ptr);
+	dbg->type = kstrdup(c_ptr, GFP_KERNEL);
+	if (!dbg->type) {
+		kfree(dbg->name);
+		devm_kfree(info->dev, dbg);
+		return NULL;
+	}
+
+	snprintf(top_dir, 16, "%d", info->id);
+	top_dentry = debugfs_create_dir(top_dir, scmi_top_dentry);
+	trans = debugfs_create_dir("transport", top_dentry);
+
+	dbg->is_atomic = info->desc->atomic_enabled &&
+				is_transport_polling_capable(info->desc);
+
+	debugfs_create_str("instance_name", 0400, top_dentry,
+			   (char **)&dbg->name);
+
+	debugfs_create_u32("atomic_threshold_us", 0400, top_dentry,
+			   &info->atomic_threshold);
+
+	debugfs_create_str("type", 0400, trans, (char **)&dbg->type);
+
+	debugfs_create_bool("is_atomic", 0400, trans, &dbg->is_atomic);
+
+	debugfs_create_u32("max_rx_timeout_ms", 0400, trans,
+			   (u32 *)&info->desc->max_rx_timeout_ms);
+
+	debugfs_create_u32("max_msg_size", 0400, trans,
+			   (u32 *)&info->desc->max_msg_size);
+
+	debugfs_create_u32("tx_max_msg", 0400, trans,
+			   (u32 *)&info->tx_minfo.max_msg);
+
+	debugfs_create_u32("rx_max_msg", 0400, trans,
+			   (u32 *)&info->rx_minfo.max_msg);
+
+	dbg->top_dentry = top_dentry;
+
+	if (devm_add_action_or_reset(info->dev,
+				     scmi_debugfs_common_cleanup, dbg)) {
+		scmi_debugfs_common_cleanup(dbg);
+		return NULL;
+	}
+
+	return dbg;
+}
+
 static int scmi_probe(struct platform_device *pdev)
 {
 	int ret;
@@ -2552,6 +2648,12 @@ static int scmi_probe(struct platform_device *pdev)
 	if (ret)
 		goto clear_dev_req_notifier;
 
+	if (scmi_top_dentry) {
+		info->dbg = scmi_debugfs_common_setup(info);
+		if (!info->dbg)
+			dev_warn(dev, "Failed to setup SCMI debugfs.\n");
+	}
+
 	if (scmi_notification_init(handle))
 		dev_err(dev, "SCMI Notifications NOT available.\n");
 
@@ -2781,6 +2883,19 @@ static void __exit scmi_transports_exit(void)
 	__scmi_transports_setup(false);
 }
 
+static struct dentry *scmi_debugfs_init(void)
+{
+	struct dentry *d;
+
+	d = debugfs_create_dir("scmi", NULL);
+	if (IS_ERR(d)) {
+		pr_err("Could NOT create SCMI top dentry.\n");
+		return NULL;
+	}
+
+	return d;
+}
+
 static int __init scmi_driver_init(void)
 {
 	int ret;
@@ -2794,6 +2909,9 @@ static int __init scmi_driver_init(void)
 	if (ret)
 		return ret;
 
+	if (IS_ENABLED(CONFIG_ARM_SCMI_NEED_DEBUGFS))
+		scmi_top_dentry = scmi_debugfs_init();
+
 	scmi_base_register();
 
 	scmi_clock_register();
@@ -2825,6 +2943,8 @@ static void __exit scmi_driver_exit(void)
 	scmi_transports_exit();
 
 	platform_driver_unregister(&scmi_driver);
+
+	debugfs_remove_recursive(scmi_top_dentry);
 }
 module_exit(scmi_driver_exit);
 
-- 
2.34.1

[PATCH v8 11/17] firmware: arm_scmi: Add debugfs ABI documentation for common entries

[Cristian Marussi]

Add description of the debugfs SCMI common ABI.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 Documentation/ABI/testing/debugfs-scmi | 70 ++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 Documentation/ABI/testing/debugfs-scmi

diff --git a/Documentation/ABI/testing/debugfs-scmi b/Documentation/ABI/testing/debugfs-scmi
new file mode 100644
index 000000000000..ee7179ab2edf
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-scmi
@@ -0,0 +1,70 @@
+What:		/sys/kernel/debug/scmi/<n>/instance_name
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	The name of the underlying SCMI instance <n> described by
+		all the debugfs accessors rooted at /sys/kernel/debug/scmi/<n>,
+		expressed as the full name of the top DT SCMI node under which
+		this SCMI instance is rooted.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/atomic_threshold_us
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	An optional time value, expressed in microseconds, representing,
+		on this SCMI instance <n>, the threshold above which any SCMI
+		command, advertised to have an higher-than-threshold execution
+		latency, should not be considered for atomic mode of operation,
+		even if requested.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/type
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	A string representing the type of transport configured for this
+		SCMI instance <n>.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/is_atomic
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	A boolean stating if the transport configured on the underlying
+		SCMI instance <n> is capable of atomic mode of operation.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/max_rx_timeout_ms
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	Timeout in milliseconds allowed for SCMI synchronous replies
+		for the currently configured SCMI transport for instance <n>.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/max_msg_size
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	Max message size of allowed SCMI messages for the currently
+		configured SCMI transport for instance <n>.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/tx_max_msg
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	Max number of concurrently allowed in-flight SCMI messages for
+		the currently configured SCMI transport for instance <n> on the
+		TX channels.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/transport/rx_max_msg
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	Max number of concurrently allowed in-flight SCMI messages for
+		the currently configured SCMI transport for instance <n> on the
+		RX channels.
+Users:		Debugging, any userspace test suite
-- 
2.34.1

[PATCH v8 12/17] firmware: arm_scmi: Add core Raw transmission support

[Cristian Marussi]

Add SCMI Raw mode support which exposes a userspace interface to allow for
bare SCMI command injection and snooping from userspace.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v7 --> v8
- remove debugfs unneeded error checking in scmi_raw_mode_init
v5 --> v6
- refactored Raw queues mgmt
- using is_raw as a bitflag
- fix debugfs multiple writers cases
- added DEBUG_FS dependency
- select CONFIG_ARM_SCMI_NEED_DEBUGFS when Raw mode is compiled in
- change multiple servers support rootfs to <debugfs>/scmi/0/raw/
- remove instance data from Raw debugfs since already hold in the common
  debugfs instance
- fixed DOC comments
v4 --> v5
- avoid using raw_buffers in scmi_raw_error_report, prefer
  dynalloc GFP_ATOMIC
- use custom tags for Raw msg_dump traces
- use xfer->is_raw to enforce segregation of Raw transactions
- add multiple SCMI server instance support. New Raw debugfs is at
	<debugfs>/scmi_raw/0/...
- fix possible race in scmi_raw_message_dequeue between list_empty
  check and effective dequeuing.
- add circular handling of raw buffers queues for errors and
  notifications
v3 --> v4
- fix handling of O_NONBLOCK raw_mode read requests
- add support for polled/nocomnpletion_irq transports
- removed inlines
v2 --> v3
- changed to dev_dbg when retrying inflight reg
- refactored and simplfiied waiters deferred worker
- fixed sparse errors about LE and __poll_t
v1 --> v2
- make use of proper channel depending on protocol at hand (using
  scmi_xfer_raw_channel_get to lookup related DT config)
- refactored scmi_inflight_register call
- added debugfs docs and comments
---
 drivers/firmware/arm_scmi/Kconfig    |   15 +
 drivers/firmware/arm_scmi/Makefile   |    1 +
 drivers/firmware/arm_scmi/driver.c   |    6 +-
 drivers/firmware/arm_scmi/raw_mode.c | 1322 ++++++++++++++++++++++++++
 drivers/firmware/arm_scmi/raw_mode.h |   30 +
 5 files changed, 1372 insertions(+), 2 deletions(-)
 create mode 100644 drivers/firmware/arm_scmi/raw_mode.c
 create mode 100644 drivers/firmware/arm_scmi/raw_mode.h

diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig
index f36f89a22740..3b4f9e92b1e3 100644
--- a/drivers/firmware/arm_scmi/Kconfig
+++ b/drivers/firmware/arm_scmi/Kconfig
@@ -30,6 +30,21 @@ config ARM_SCMI_NEED_DEBUGFS
 	  which needs debugfs support. When selected causess the creation
 	  of a common SCMI debugfs root directory.
 
+config ARM_SCMI_RAW_MODE_SUPPORT
+	bool "Enable support for SCMI Raw transmission mode"
+	depends on DEBUG_FS
+	select ARM_SCMI_NEED_DEBUGFS
+	help
+	  Enable support for SCMI Raw transmission mode.
+
+	  If enabled allows the direct injection and snooping of SCMI bare
+	  messages through a dedicated debugfs interface.
+	  It is meant to be used by SCMI compliance/testing suites.
+
+	  When enabled regular SCMI drivers interactions are inhibited in
+	  order to avoid unexpected interactions with the SCMI Raw message
+	  flow. If unsure say N.
+
 config ARM_SCMI_HAVE_TRANSPORT
 	bool
 	help
diff --git a/drivers/firmware/arm_scmi/Makefile b/drivers/firmware/arm_scmi/Makefile
index f0596c386c62..b31d78fa66cc 100644
--- a/drivers/firmware/arm_scmi/Makefile
+++ b/drivers/firmware/arm_scmi/Makefile
@@ -3,6 +3,7 @@ scmi-bus-y = bus.o
 scmi-core-objs := $(scmi-bus-y)
 
 scmi-driver-y = driver.o notify.o
+scmi-driver-$(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT) += raw_mode.o
 scmi-transport-$(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
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 5d5defd92403..2b96d9c3489d 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -920,7 +920,8 @@ static void scmi_handle_response(struct scmi_chan_info *cinfo,
 	trace_scmi_msg_dump(info->id, cinfo->id, xfer->hdr.protocol_id,
 			    xfer->hdr.id,
 			    xfer->hdr.type == MSG_TYPE_DELAYED_RESP ?
-			    "DLYD" : "RESP",
+			    (!SCMI_XFER_IS_RAW(xfer) ? "DLYD" : "dlyd") :
+			    (!SCMI_XFER_IS_RAW(xfer) ? "RESP" : "resp"),
 			    xfer->hdr.seq, xfer->hdr.status,
 			    xfer->rx.buf, xfer->rx.len);
 
@@ -1045,7 +1046,8 @@ static int scmi_wait_for_reply(struct device *dev, const struct scmi_desc *desc,
 			/* Trace polled replies. */
 			trace_scmi_msg_dump(info->id, cinfo->id,
 					    xfer->hdr.protocol_id, xfer->hdr.id,
-					    "RESP",
+					    !SCMI_XFER_IS_RAW(xfer) ?
+					    "RESP" : "resp",
 					    xfer->hdr.seq, xfer->hdr.status,
 					    xfer->rx.buf, xfer->rx.len);
 		}
diff --git a/drivers/firmware/arm_scmi/raw_mode.c b/drivers/firmware/arm_scmi/raw_mode.c
new file mode 100644
index 000000000000..a33ef0eaffe5
--- /dev/null
+++ b/drivers/firmware/arm_scmi/raw_mode.c
@@ -0,0 +1,1322 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * System Control and Management Interface (SCMI) Raw mode support
+ *
+ * Copyright (C) 2022 ARM Ltd.
+ */
+/**
+ * DOC: Theory of operation
+ *
+ * When enabled the SCMI Raw mode support exposes a userspace API which allows
+ * to send and receive SCMI commands, replies and notifications from a user
+ * application through injection and snooping of bare SCMI messages in binary
+ * little-endian format.
+ *
+ * Such injected SCMI transactions will then be routed through the SCMI core
+ * stack towards the SCMI backend server using whatever SCMI transport is
+ * currently configured on the system under test.
+ *
+ * It is meant to help in running any sort of SCMI backend server testing, no
+ * matter where the server is placed, as long as it is normally reachable via
+ * the transport configured on the system.
+ *
+ * It is activated by a Kernel configuration option since it is NOT meant to
+ * be used in production but only during development and in CI deployments.
+ *
+ * In order to avoid possible interferences between the SCMI Raw transactions
+ * originated from a test-suite and the normal operations of the SCMI drivers,
+ * when Raw mode is enabled, by default, all the regular SCMI drivers are
+ * inhibited.
+ *
+ * The exposed API is as follows.
+ *
+ * All SCMI Raw entries are rooted under a common top /raw debugfs top directory
+ * which in turn is rooted under the corresponding underlying  SCMI instance.
+ *
+ * /sys/kernel/debug/scmi/
+ * |-- 0
+ *     |-- atomic_threshold_us
+ *     |-- instance_name
+ *     |-- raw
+ *     |   |-- errors
+ *     |   |-- message
+ *     |   |-- message_async
+ *     |   |-- notification
+ *     |   `-- reset
+ *     `-- transport
+ *         |-- is_atomic
+ *         |-- max_msg_size
+ *         |-- max_rx_timeout_ms
+ *         |-- rx_max_msg
+ *         |-- tx_max_msg
+ *         `-- type
+ *
+ * where:
+ *
+ *  - errors: used to read back timed-out and unexpected replies
+ *  - message*: used to send sync/async commands and read back immediate and
+ *		delayed reponses (if any)
+ *  - notification: used to read any notification being emitted by the system
+ *		    (if previously enabled by the user app)
+ *  - reset: used to flush the queues of messages (of any kind) still pending
+ *	     to be read; this is useful at test-suite start/stop to get
+ *	     rid of any unread messages from the previous run.
+ *
+ * Note that other common general entries are available under transport/ to let
+ * the user applications properly make up their expectations in terms of
+ * timeouts and message characteristics.
+ *
+ * Each write to the message* entries causes one command request to be built
+ * and sent while the replies or delayed response are read back from those same
+ * entries one message at time (receiving an EOF at each message boundary).
+ *
+ * The user application running the test is in charge of handling timeouts
+ * on replies and properly choosing SCMI sequence numbers for the outgoing
+ * requests (using the same sequence number is supported but discouraged).
+ *
+ * Injection of multiple in-flight requests is supported as long as the user
+ * application uses properly distinct sequence numbers for concurrent requests
+ * and takes care to properly manage all the related issues about concurrency
+ * and command/reply pairing. Keep in mind that, anyway, the real level of
+ * parallelism attainable in such scenario is dependent on the characteristics
+ * of the underlying transport being used.
+ *
+ * Since the SCMI core regular stack is partially used to deliver and collect
+ * the messages, late replies arrived after timeouts and any other sort of
+ * unexpected message can be identified by the SCMI core as usual and they will
+ * be reported as messages under "errors" for later analysis.
+ */
+
+#include <linux/bitmap.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/idr.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/poll.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#include "common.h"
+
+#include "raw_mode.h"
+
+#include <trace/events/scmi.h>
+
+#define SCMI_XFER_RAW_MAX_RETRIES	10
+
+/**
+ * struct scmi_raw_queue  - Generic Raw queue descriptor
+ *
+ * @free_bufs: A freelists listhead used to keep unused raw buffers
+ * @free_bufs_lock: Spinlock used to protect access to @free_bufs
+ * @msg_q: A listhead to a queue of snooped messages waiting to be read out
+ * @msg_q_lock: Spinlock used to protect access to @msg_q
+ * @wq: A waitqueue used to wait and poll on related @msg_q
+ */
+struct scmi_raw_queue {
+	struct list_head free_bufs;
+	/* Protect free_bufs[] lists */
+	spinlock_t free_bufs_lock;
+	struct list_head msg_q;
+	/* Protect msg_q[] lists */
+	spinlock_t msg_q_lock;
+	wait_queue_head_t wq;
+};
+
+/**
+ * struct scmi_raw_mode_info  - Structure holding SCMI Raw instance data
+ *
+ * @id: Sequential Raw instance ID.
+ * @handle: Pointer to SCMI entity handle to use
+ * @desc: Pointer to the transport descriptor to use
+ * @tx_max_msg: Maximum number of concurrent TX in-flight messages
+ * @q: An array of Raw queue descriptors
+ * @free_waiters: Head of freelist for unused waiters
+ * @free_mtx: A mutex to protect the waiters freelist
+ * @active_waiters: Head of list for currently active and used waiters
+ * @active_mtx: A mutex to protect the active waiters list
+ * @waiters_work: A work descriptor to be used with the workqueue machinery
+ * @wait_wq: A workqueue reference to the created workqueue
+ * @dentry: Top debugfs root dentry for SCMI Raw
+ * @gid: A group ID used for devres accounting
+ *
+ * Note that this descriptor is passed back to the core after SCMI Raw is
+ * initialized as an opaque handle to use by subsequent SCMI Raw call hooks.
+ *
+ */
+struct scmi_raw_mode_info {
+	unsigned int id;
+	const struct scmi_handle *handle;
+	const struct scmi_desc *desc;
+	int tx_max_msg;
+	struct scmi_raw_queue *q[SCMI_RAW_MAX_QUEUE];
+	struct list_head free_waiters;
+	/* Protect free_waiters list */
+	struct mutex free_mtx;
+	struct list_head active_waiters;
+	/* Protect active_waiters list */
+	struct mutex active_mtx;
+	struct work_struct waiters_work;
+	struct workqueue_struct	*wait_wq;
+	struct dentry *dentry;
+	void *gid;
+};
+
+/**
+ * struct scmi_xfer_raw_waiter  - Structure to describe an xfer to be waited for
+ *
+ * @start_jiffies: The timestamp in jiffies of when this structure was queued.
+ * @cinfo: A reference to the channel to use for this transaction
+ * @xfer: A reference to the xfer to be waited for
+ * @async_response: A completion to be, optionally, used for async waits: it
+ *		    will be setup by @scmi_do_xfer_raw_start, if needed, to be
+ *		    pointed at by xfer->async_done.
+ * @node: A list node.
+ */
+struct scmi_xfer_raw_waiter {
+	unsigned long start_jiffies;
+	struct scmi_chan_info *cinfo;
+	struct scmi_xfer *xfer;
+	struct completion async_response;
+	struct list_head node;
+};
+
+/**
+ * struct scmi_raw_buffer  - Structure to hold a full SCMI message
+ *
+ * @max_len: The maximum allowed message size (header included) that can be
+ *	     stored into @msg
+ * @msg: A message buffer used to collect a full message grabbed from an xfer.
+ * @node: A list node.
+ */
+struct scmi_raw_buffer {
+	size_t max_len;
+	struct scmi_msg msg;
+	struct list_head node;
+};
+
+/**
+ * struct scmi_dbg_raw_data  - Structure holding data needed by the debugfs
+ * layer
+ *
+ * @raw: A reference to the Raw instance.
+ * @tx: A message buffer used to collect TX message on write.
+ * @tx_size: The effective size of the TX message.
+ * @tx_req_size: The final expected size of the complete TX message.
+ * @rx: A message buffer to collect RX message on read.
+ * @rx_size: The effective size of the RX message.
+ */
+struct scmi_dbg_raw_data {
+	struct scmi_raw_mode_info *raw;
+	struct scmi_msg tx;
+	size_t tx_size;
+	size_t tx_req_size;
+	struct scmi_msg rx;
+	size_t rx_size;
+};
+
+static struct scmi_raw_buffer *scmi_raw_buffer_get(struct scmi_raw_queue *q)
+{
+	unsigned long flags;
+	struct scmi_raw_buffer *rb = NULL;
+	struct list_head *head = &q->free_bufs;
+
+	spin_lock_irqsave(&q->free_bufs_lock, flags);
+	if (!list_empty(head)) {
+		rb = list_first_entry(head, struct scmi_raw_buffer, node);
+		list_del_init(&rb->node);
+	}
+	spin_unlock_irqrestore(&q->free_bufs_lock, flags);
+
+	return rb;
+}
+
+static void scmi_raw_buffer_put(struct scmi_raw_queue *q,
+				struct scmi_raw_buffer *rb)
+{
+	unsigned long flags;
+
+	/* Reset to full buffer length */
+	rb->msg.len = rb->max_len;
+
+	spin_lock_irqsave(&q->free_bufs_lock, flags);
+	list_add_tail(&rb->node, &q->free_bufs);
+	spin_unlock_irqrestore(&q->free_bufs_lock, flags);
+}
+
+static void scmi_raw_buffer_enqueue(struct scmi_raw_queue *q,
+				    struct scmi_raw_buffer *rb)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&q->msg_q_lock, flags);
+	list_add_tail(&rb->node, &q->msg_q);
+	spin_unlock_irqrestore(&q->msg_q_lock, flags);
+
+	wake_up_interruptible(&q->wq);
+}
+
+static struct scmi_raw_buffer*
+scmi_raw_buffer_dequeue_unlocked(struct scmi_raw_queue *q)
+{
+	struct scmi_raw_buffer *rb = NULL;
+
+	if (!list_empty(&q->msg_q)) {
+		rb = list_first_entry(&q->msg_q, struct scmi_raw_buffer, node);
+		list_del_init(&rb->node);
+	}
+
+	return rb;
+}
+
+static struct scmi_raw_buffer *scmi_raw_buffer_dequeue(struct scmi_raw_queue *q)
+{
+	unsigned long flags;
+	struct scmi_raw_buffer *rb;
+
+	spin_lock_irqsave(&q->msg_q_lock, flags);
+	rb = scmi_raw_buffer_dequeue_unlocked(q);
+	spin_unlock_irqrestore(&q->msg_q_lock, flags);
+
+	return rb;
+}
+
+static void scmi_raw_buffer_queue_flush(struct scmi_raw_queue *q)
+{
+	struct scmi_raw_buffer *rb;
+
+	do {
+		rb = scmi_raw_buffer_dequeue(q);
+		if (rb)
+			scmi_raw_buffer_put(q, rb);
+	} while (rb);
+}
+
+static struct scmi_xfer_raw_waiter *
+scmi_xfer_raw_waiter_get(struct scmi_raw_mode_info *raw, struct scmi_xfer *xfer,
+			 struct scmi_chan_info *cinfo, bool async)
+{
+	struct scmi_xfer_raw_waiter *rw = NULL;
+
+	mutex_lock(&raw->free_mtx);
+	if (!list_empty(&raw->free_waiters)) {
+		rw = list_first_entry(&raw->free_waiters,
+				      struct scmi_xfer_raw_waiter, node);
+		list_del_init(&rw->node);
+
+		if (async) {
+			reinit_completion(&rw->async_response);
+			xfer->async_done = &rw->async_response;
+		}
+
+		rw->cinfo = cinfo;
+		rw->xfer = xfer;
+	}
+	mutex_unlock(&raw->free_mtx);
+
+	return rw;
+}
+
+static void scmi_xfer_raw_waiter_put(struct scmi_raw_mode_info *raw,
+				     struct scmi_xfer_raw_waiter *rw)
+{
+	if (rw->xfer) {
+		rw->xfer->async_done = NULL;
+		rw->xfer = NULL;
+	}
+
+	mutex_lock(&raw->free_mtx);
+	list_add_tail(&rw->node, &raw->free_waiters);
+	mutex_unlock(&raw->free_mtx);
+}
+
+static void scmi_xfer_raw_waiter_enqueue(struct scmi_raw_mode_info *raw,
+					 struct scmi_xfer_raw_waiter *rw)
+{
+	/* A timestamp for the deferred worker to know how much this has aged */
+	rw->start_jiffies = jiffies;
+
+	trace_scmi_xfer_response_wait(rw->xfer->transfer_id, rw->xfer->hdr.id,
+				      rw->xfer->hdr.protocol_id,
+				      rw->xfer->hdr.seq,
+				      raw->desc->max_rx_timeout_ms,
+				      rw->xfer->hdr.poll_completion);
+
+	mutex_lock(&raw->active_mtx);
+	list_add_tail(&rw->node, &raw->active_waiters);
+	mutex_unlock(&raw->active_mtx);
+
+	/* kick waiter work */
+	queue_work(raw->wait_wq, &raw->waiters_work);
+}
+
+static struct scmi_xfer_raw_waiter *
+scmi_xfer_raw_waiter_dequeue(struct scmi_raw_mode_info *raw)
+{
+	struct scmi_xfer_raw_waiter *rw = NULL;
+
+	mutex_lock(&raw->active_mtx);
+	if (!list_empty(&raw->active_waiters)) {
+		rw = list_first_entry(&raw->active_waiters,
+				      struct scmi_xfer_raw_waiter, node);
+		list_del_init(&rw->node);
+	}
+	mutex_unlock(&raw->active_mtx);
+
+	return rw;
+}
+
+/**
+ * scmi_xfer_raw_worker  - Work function to wait for Raw xfers completions
+ *
+ * @work: A reference to the work.
+ *
+ * In SCMI Raw mode, once a user-provided injected SCMI message is sent, we
+ * cannot wait to receive its response (if any) in the context of the injection
+ * routines so as not to leave the userspace write syscall, which delivered the
+ * SCMI message to send, pending till eventually a reply is received.
+ * Userspace should and will poll/wait instead on the read syscalls which will
+ * be in charge of reading a received reply (if any).
+ *
+ * Even though reply messages are collected and reported into the SCMI Raw layer
+ * on the RX path, nonetheless we have to properly wait for their completion as
+ * usual (and async_completion too if needed) in order to properly release the
+ * xfer structure at the end: to do this out of the context of the write/send
+ * these waiting jobs are delegated to this deferred worker.
+ *
+ * Any sent xfer, to be waited for, is timestamped and queued for later
+ * consumption by this worker: queue aging is accounted for while choosing a
+ * timeout for the completion, BUT we do not really care here if we end up
+ * accidentally waiting for a bit too long.
+ */
+static void scmi_xfer_raw_worker(struct work_struct *work)
+{
+	struct scmi_raw_mode_info *raw;
+	struct device *dev;
+	unsigned long max_tmo;
+
+	raw = container_of(work, struct scmi_raw_mode_info, waiters_work);
+	dev = raw->handle->dev;
+	max_tmo = msecs_to_jiffies(raw->desc->max_rx_timeout_ms);
+
+	do {
+		int ret = 0;
+		unsigned int timeout_ms;
+		unsigned long aging;
+		struct scmi_xfer *xfer;
+		struct scmi_xfer_raw_waiter *rw;
+		struct scmi_chan_info *cinfo;
+
+		rw = scmi_xfer_raw_waiter_dequeue(raw);
+		if (!rw)
+			return;
+
+		cinfo = rw->cinfo;
+		xfer = rw->xfer;
+		/*
+		 * Waiters are queued by wait-deadline at the end, so some of
+		 * them could have been already expired when processed, BUT we
+		 * have to check the completion status anyway just in case a
+		 * virtually expired (aged) transaction was indeed completed
+		 * fine and we'll have to wait for the asynchronous part (if
+		 * any): for this reason a 1 ms timeout is used for already
+		 * expired/aged xfers.
+		 */
+		aging = jiffies - rw->start_jiffies;
+		timeout_ms = max_tmo > aging ?
+			jiffies_to_msecs(max_tmo - aging) : 1;
+
+		ret = scmi_xfer_raw_wait_for_message_response(cinfo, xfer,
+							      timeout_ms);
+		if (!ret && xfer->hdr.status)
+			ret = scmi_to_linux_errno(xfer->hdr.status);
+
+		if (raw->desc->ops->mark_txdone)
+			raw->desc->ops->mark_txdone(rw->cinfo, ret, xfer);
+
+		trace_scmi_xfer_end(xfer->transfer_id, xfer->hdr.id,
+				    xfer->hdr.protocol_id, xfer->hdr.seq, ret);
+
+		/* Wait also for an async delayed response if needed */
+		if (!ret && xfer->async_done) {
+			unsigned long tmo = msecs_to_jiffies(SCMI_MAX_RESPONSE_TIMEOUT);
+
+			if (!wait_for_completion_timeout(xfer->async_done, tmo))
+				dev_err(dev,
+					"timed out in RAW delayed resp - HDR:%08X\n",
+					pack_scmi_header(&xfer->hdr));
+		}
+
+		/* Release waiter and xfer */
+		scmi_xfer_raw_put(raw->handle, xfer);
+		scmi_xfer_raw_waiter_put(raw, rw);
+	} while (1);
+}
+
+static void scmi_xfer_raw_reset(struct scmi_raw_mode_info *raw)
+{
+	int i;
+
+	dev_info(raw->handle->dev, "Resetting SCMI Raw stack.\n");
+
+	for (i = 0; i < SCMI_RAW_MAX_QUEUE; i++)
+		scmi_raw_buffer_queue_flush(raw->q[i]);
+}
+
+/**
+ * scmi_xfer_raw_get_init  - An helper to build a valid xfer from the provided
+ * bare SCMI message.
+ *
+ * @raw: A reference to the Raw instance.
+ * @buf: A buffer containing the whole SCMI message to send (including the
+ *	 header) in little-endian binary formmat.
+ * @len: Length of the message in @buf.
+ * @p: A pointer to return the initialized Raw xfer.
+ *
+ * After an xfer is picked from the TX pool and filled in with the message
+ * content, the xfer is registered as pending with the core in the usual way
+ * using the original sequence number provided by the user with the message.
+ *
+ * Note that, in case the testing user application is NOT using distinct
+ * sequence-numbers between successive SCMI messages such registration could
+ * fail temporarily if the previous message, using the same sequence number,
+ * had still not released; in such a case we just wait and retry.
+ *
+ * Return: 0 on Success
+ */
+static int scmi_xfer_raw_get_init(struct scmi_raw_mode_info *raw, void *buf,
+				  size_t len, struct scmi_xfer **p)
+{
+	u32 msg_hdr;
+	size_t tx_size;
+	struct scmi_xfer *xfer;
+	int ret, retry = SCMI_XFER_RAW_MAX_RETRIES;
+	struct device *dev = raw->handle->dev;
+
+	if (!buf || len < sizeof(u32))
+		return -EINVAL;
+
+	tx_size = len - sizeof(u32);
+	/* Ensure we have sane transfer sizes */
+	if (tx_size > raw->desc->max_msg_size)
+		return -ERANGE;
+
+	xfer = scmi_xfer_raw_get(raw->handle);
+	if (IS_ERR(xfer)) {
+		dev_warn(dev, "RAW - Cannot get a free RAW xfer !\n");
+		return PTR_ERR(xfer);
+	}
+
+	/* Build xfer from the provided SCMI bare LE message */
+	msg_hdr = le32_to_cpu(*((__le32 *)buf));
+	unpack_scmi_header(msg_hdr, &xfer->hdr);
+	xfer->hdr.seq = (u16)MSG_XTRACT_TOKEN(msg_hdr);
+	/* Polling not supported */
+	xfer->hdr.poll_completion = false;
+	xfer->hdr.status = SCMI_SUCCESS;
+	xfer->tx.len = tx_size;
+	xfer->rx.len = raw->desc->max_msg_size;
+	/* Clear the whole TX buffer */
+	memset(xfer->tx.buf, 0x00, raw->desc->max_msg_size);
+	if (xfer->tx.len)
+		memcpy(xfer->tx.buf, (u8 *)buf + sizeof(msg_hdr), xfer->tx.len);
+	*p = xfer;
+
+	/*
+	 * In flight registration can temporarily fail in case of Raw messages
+	 * if the user injects messages without using monotonically increasing
+	 * sequence numbers since, in Raw mode, the xfer (and the token) is
+	 * finally released later by a deferred worker. Just retry for a while.
+	 */
+	do {
+		ret = scmi_xfer_raw_inflight_register(raw->handle, xfer);
+		if (ret) {
+			dev_dbg(dev,
+				"...retrying[%d] inflight registration\n",
+				retry);
+			msleep(raw->desc->max_rx_timeout_ms /
+			       SCMI_XFER_RAW_MAX_RETRIES);
+		}
+	} while (ret && --retry);
+
+	if (ret) {
+		dev_warn(dev,
+			 "RAW - Could NOT register xfer %d in-flight HDR:0x%08X\n",
+			 xfer->hdr.seq, msg_hdr);
+		scmi_xfer_raw_put(raw->handle, xfer);
+	}
+
+	return ret;
+}
+
+/**
+ * scmi_do_xfer_raw_start  - An helper to send a valid raw xfer
+ *
+ * @raw: A reference to the Raw instance.
+ * @xfer: The xfer to send
+ * @async: A flag stating if an asynchronous command is required.
+ *
+ * This function send a previously built raw xfer using an appropriate channel
+ * and queues the related waiting work.
+ *
+ * Note that we need to know explicitly if the required command is meant to be
+ * asynchronous in kind since we have to properly setup the waiter.
+ * (and deducing this from the payload is weak and do not scale given there is
+ *  NOT a common header-flag stating if the command is asynchronous or not)
+ *
+ * Return: 0 on Success
+ */
+static int scmi_do_xfer_raw_start(struct scmi_raw_mode_info *raw,
+				  struct scmi_xfer *xfer, bool async)
+{
+	int ret;
+	struct scmi_chan_info *cinfo;
+	struct scmi_xfer_raw_waiter *rw;
+	struct device *dev = raw->handle->dev;
+
+	cinfo = scmi_xfer_raw_channel_get(raw->handle, xfer->hdr.protocol_id);
+	if (IS_ERR(cinfo))
+		return PTR_ERR(cinfo);
+
+	rw = scmi_xfer_raw_waiter_get(raw, xfer, cinfo, async);
+	if (!rw) {
+		dev_warn(dev, "RAW - Cannot get a free waiter !\n");
+		return -ENOMEM;
+	}
+
+	/* True ONLY if also supported by transport. */
+	if (is_polling_enabled(cinfo, raw->desc))
+		xfer->hdr.poll_completion = true;
+
+	reinit_completion(&xfer->done);
+	/* Make sure xfer state update is visible before sending */
+	smp_store_mb(xfer->state, SCMI_XFER_SENT_OK);
+
+	trace_scmi_xfer_begin(xfer->transfer_id, xfer->hdr.id,
+			      xfer->hdr.protocol_id, xfer->hdr.seq,
+			      xfer->hdr.poll_completion);
+
+	ret = raw->desc->ops->send_message(rw->cinfo, xfer);
+	if (ret) {
+		dev_err(dev, "Failed to send RAW message %d\n", ret);
+		scmi_xfer_raw_waiter_put(raw, rw);
+		return ret;
+	}
+
+	trace_scmi_msg_dump(raw->id, cinfo->id, xfer->hdr.protocol_id,
+			    xfer->hdr.id, "cmnd", xfer->hdr.seq,
+			    xfer->hdr.status,
+			    xfer->tx.buf, xfer->tx.len);
+
+	scmi_xfer_raw_waiter_enqueue(raw, rw);
+
+	return ret;
+}
+
+/**
+ * scmi_raw_message_send  - An helper to build and send an SCMI command using
+ * the provided SCMI bare message buffer
+ *
+ * @raw: A reference to the Raw instance.
+ * @buf: A buffer containing the whole SCMI message to send (including the
+ *	 header) in little-endian binary format.
+ * @len: Length of the message in @buf.
+ * @async: A flag stating if an asynchronous command is required.
+ *
+ * Return: 0 on Success
+ */
+static int scmi_raw_message_send(struct scmi_raw_mode_info *raw,
+				 void *buf, size_t len, bool async)
+{
+	int ret;
+	struct scmi_xfer *xfer;
+
+	ret = scmi_xfer_raw_get_init(raw, buf, len, &xfer);
+	if (ret)
+		return ret;
+
+	ret = scmi_do_xfer_raw_start(raw, xfer, async);
+	if (ret)
+		scmi_xfer_raw_put(raw->handle, xfer);
+
+	return ret;
+}
+
+static struct scmi_raw_buffer *
+scmi_raw_message_dequeue(struct scmi_raw_queue *q, bool o_nonblock)
+{
+	unsigned long flags;
+	struct scmi_raw_buffer *rb;
+
+	spin_lock_irqsave(&q->msg_q_lock, flags);
+	while (list_empty(&q->msg_q)) {
+		spin_unlock_irqrestore(&q->msg_q_lock, flags);
+
+		if (o_nonblock)
+			return ERR_PTR(-EAGAIN);
+
+		if (wait_event_interruptible(q->wq, !list_empty(&q->msg_q)))
+			return ERR_PTR(-ERESTARTSYS);
+
+		spin_lock_irqsave(&q->msg_q_lock, flags);
+	}
+
+	rb = scmi_raw_buffer_dequeue_unlocked(q);
+
+	spin_unlock_irqrestore(&q->msg_q_lock, flags);
+
+	return rb;
+}
+
+/**
+ * scmi_raw_message_receive  - An helper to dequeue and report the next
+ * available enqueued raw message payload that has been collected.
+ *
+ * @raw: A reference to the Raw instance.
+ * @buf: A buffer to get hold of the whole SCMI message received and represented
+ *	 in little-endian binary format.
+ * @len: Length of @buf.
+ * @size: The effective size of the message copied into @buf
+ * @idx: The index of the queue to pick the next queued message from.
+ * @o_nonblock: A flag to request a non-blocking message dequeue.
+ *
+ * Return: 0 on Success
+ */
+static int scmi_raw_message_receive(struct scmi_raw_mode_info *raw,
+				    void *buf, size_t len, size_t *size,
+				    unsigned int idx,
+				    bool o_nonblock)
+{
+	int ret = 0;
+	struct scmi_raw_buffer *rb;
+	struct scmi_raw_queue *q = raw->q[idx];
+
+	rb = scmi_raw_message_dequeue(q, o_nonblock);
+	if (IS_ERR(rb)) {
+		dev_dbg(raw->handle->dev, "RAW - No message available!\n");
+		return PTR_ERR(rb);
+	}
+
+	if (rb->msg.len <= len) {
+		memcpy(buf, rb->msg.buf, rb->msg.len);
+		*size = rb->msg.len;
+	} else {
+		ret = -ENOSPC;
+	}
+
+	scmi_raw_buffer_put(q, rb);
+
+	return ret;
+}
+
+/* SCMI Raw debugfs helpers */
+
+static ssize_t scmi_dbg_raw_mode_common_read(struct file *filp,
+					     char __user *buf,
+					     size_t count, loff_t *ppos,
+					     unsigned int idx)
+{
+	ssize_t cnt;
+	struct scmi_dbg_raw_data *rd = filp->private_data;
+
+	if (!rd->rx_size) {
+		int ret;
+
+		ret = scmi_raw_message_receive(rd->raw, rd->rx.buf, rd->rx.len,
+					       &rd->rx_size, idx,
+					       filp->f_flags & O_NONBLOCK);
+		if (ret) {
+			rd->rx_size = 0;
+			return ret;
+		}
+
+		/* Reset any previous filepos change, including writes */
+		*ppos = 0;
+	} else if (*ppos == rd->rx_size) {
+		/* Return EOF once all the message has been read-out */
+		rd->rx_size = 0;
+		return 0;
+	}
+
+	cnt = simple_read_from_buffer(buf, count, ppos,
+				      rd->rx.buf, rd->rx_size);
+
+	return cnt;
+}
+
+static ssize_t scmi_dbg_raw_mode_common_write(struct file *filp,
+					      const char __user *buf,
+					      size_t count, loff_t *ppos,
+					      bool async)
+{
+	int ret;
+	struct scmi_dbg_raw_data *rd = filp->private_data;
+
+	if (count > rd->tx.len - rd->tx_size)
+		return -ENOSPC;
+
+	/* On first write attempt @count carries the total full message size. */
+	if (!rd->tx_size)
+		rd->tx_req_size = count;
+
+	/*
+	 * Gather a full message, possibly across multiple interrupted wrrtes,
+	 * before sending it with a single RAW xfer.
+	 */
+	if (rd->tx_size < rd->tx_req_size) {
+		size_t cnt;
+
+		cnt = simple_write_to_buffer(rd->tx.buf, rd->tx.len, ppos,
+					     buf, count);
+		rd->tx_size += cnt;
+		if (cnt < count)
+			return cnt;
+	}
+
+	ret = scmi_raw_message_send(rd->raw, rd->tx.buf, rd->tx_size, async);
+
+	/* Reset ppos for next message ... */
+	rd->tx_size = 0;
+	*ppos = 0;
+
+	return ret ?: count;
+}
+
+static __poll_t scmi_test_dbg_raw_common_poll(struct file *filp,
+					      struct poll_table_struct *wait,
+					      unsigned int idx)
+{
+	unsigned long flags;
+	struct scmi_dbg_raw_data *rd = filp->private_data;
+	struct scmi_raw_queue *q = rd->raw->q[idx];
+	__poll_t mask = 0;
+
+	poll_wait(filp, &q->wq, wait);
+
+	spin_lock_irqsave(&q->msg_q_lock, flags);
+	if (!list_empty(&q->msg_q))
+		mask = EPOLLIN | EPOLLRDNORM;
+	spin_unlock_irqrestore(&q->msg_q_lock, flags);
+
+	return mask;
+}
+
+static ssize_t scmi_dbg_raw_mode_message_read(struct file *filp,
+					      char __user *buf,
+					      size_t count, loff_t *ppos)
+{
+	return scmi_dbg_raw_mode_common_read(filp, buf, count, ppos,
+					     SCMI_RAW_REPLY_QUEUE);
+}
+
+static ssize_t scmi_dbg_raw_mode_message_write(struct file *filp,
+					       const char __user *buf,
+					       size_t count, loff_t *ppos)
+{
+	return scmi_dbg_raw_mode_common_write(filp, buf, count, ppos, false);
+}
+
+static __poll_t scmi_dbg_raw_mode_message_poll(struct file *filp,
+					       struct poll_table_struct *wait)
+{
+	return scmi_test_dbg_raw_common_poll(filp, wait, SCMI_RAW_REPLY_QUEUE);
+}
+
+static int scmi_dbg_raw_mode_open(struct inode *inode, struct file *filp)
+{
+	struct scmi_raw_mode_info *raw;
+	struct scmi_dbg_raw_data *rd;
+
+	if (!inode->i_private)
+		return -ENODEV;
+
+	raw = inode->i_private;
+	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
+	if (!rd)
+		return -ENOMEM;
+
+	rd->rx.len = raw->desc->max_msg_size + sizeof(u32);
+	rd->rx.buf = kzalloc(rd->rx.len, GFP_KERNEL);
+	if (!rd->rx.buf) {
+		kfree(rd);
+		return -ENOMEM;
+	}
+
+	rd->tx.len = raw->desc->max_msg_size + sizeof(u32);
+	rd->tx.buf = kzalloc(rd->tx.len, GFP_KERNEL);
+	if (!rd->tx.buf) {
+		kfree(rd->rx.buf);
+		kfree(rd);
+		return -ENOMEM;
+	}
+
+	rd->raw = raw;
+	filp->private_data = rd;
+
+	return 0;
+}
+
+static int scmi_dbg_raw_mode_release(struct inode *inode, struct file *filp)
+{
+	struct scmi_dbg_raw_data *rd = filp->private_data;
+
+	kfree(rd->rx.buf);
+	kfree(rd->tx.buf);
+	kfree(rd);
+
+	return 0;
+}
+
+static ssize_t scmi_dbg_raw_mode_reset_write(struct file *filp,
+					     const char __user *buf,
+					     size_t count, loff_t *ppos)
+{
+	struct scmi_dbg_raw_data *rd = filp->private_data;
+
+	scmi_xfer_raw_reset(rd->raw);
+
+	return count;
+}
+
+static const struct file_operations scmi_dbg_raw_mode_reset_fops = {
+	.open = scmi_dbg_raw_mode_open,
+	.release = scmi_dbg_raw_mode_release,
+	.write = scmi_dbg_raw_mode_reset_write,
+	.owner = THIS_MODULE,
+};
+
+static const struct file_operations scmi_dbg_raw_mode_message_fops = {
+	.open = scmi_dbg_raw_mode_open,
+	.release = scmi_dbg_raw_mode_release,
+	.read = scmi_dbg_raw_mode_message_read,
+	.write = scmi_dbg_raw_mode_message_write,
+	.poll = scmi_dbg_raw_mode_message_poll,
+	.owner = THIS_MODULE,
+};
+
+static ssize_t scmi_dbg_raw_mode_message_async_write(struct file *filp,
+						     const char __user *buf,
+						     size_t count, loff_t *ppos)
+{
+	return scmi_dbg_raw_mode_common_write(filp, buf, count, ppos, true);
+}
+
+static const struct file_operations scmi_dbg_raw_mode_message_async_fops = {
+	.open = scmi_dbg_raw_mode_open,
+	.release = scmi_dbg_raw_mode_release,
+	.read = scmi_dbg_raw_mode_message_read,
+	.write = scmi_dbg_raw_mode_message_async_write,
+	.poll = scmi_dbg_raw_mode_message_poll,
+	.owner = THIS_MODULE,
+};
+
+static ssize_t scmi_test_dbg_raw_mode_notif_read(struct file *filp,
+						 char __user *buf,
+						 size_t count, loff_t *ppos)
+{
+	return scmi_dbg_raw_mode_common_read(filp, buf, count, ppos,
+					     SCMI_RAW_NOTIF_QUEUE);
+}
+
+static __poll_t
+scmi_test_dbg_raw_mode_notif_poll(struct file *filp,
+				  struct poll_table_struct *wait)
+{
+	return scmi_test_dbg_raw_common_poll(filp, wait, SCMI_RAW_NOTIF_QUEUE);
+}
+
+static const struct file_operations scmi_dbg_raw_mode_notification_fops = {
+	.open = scmi_dbg_raw_mode_open,
+	.release = scmi_dbg_raw_mode_release,
+	.read = scmi_test_dbg_raw_mode_notif_read,
+	.poll = scmi_test_dbg_raw_mode_notif_poll,
+	.owner = THIS_MODULE,
+};
+
+static ssize_t scmi_test_dbg_raw_mode_errors_read(struct file *filp,
+						  char __user *buf,
+						  size_t count, loff_t *ppos)
+{
+	return scmi_dbg_raw_mode_common_read(filp, buf, count, ppos,
+					     SCMI_RAW_ERRS_QUEUE);
+}
+
+static __poll_t
+scmi_test_dbg_raw_mode_errors_poll(struct file *filp,
+				   struct poll_table_struct *wait)
+{
+	return scmi_test_dbg_raw_common_poll(filp, wait, SCMI_RAW_ERRS_QUEUE);
+}
+
+static const struct file_operations scmi_dbg_raw_mode_errors_fops = {
+	.open = scmi_dbg_raw_mode_open,
+	.release = scmi_dbg_raw_mode_release,
+	.read = scmi_test_dbg_raw_mode_errors_read,
+	.poll = scmi_test_dbg_raw_mode_errors_poll,
+	.owner = THIS_MODULE,
+};
+
+static struct scmi_raw_queue *
+scmi_raw_queue_init(struct scmi_raw_mode_info *raw)
+{
+	int i;
+	struct scmi_raw_buffer *rb;
+	struct device *dev = raw->handle->dev;
+	struct scmi_raw_queue *q;
+
+	q = devm_kzalloc(dev, sizeof(*q), GFP_KERNEL);
+	if (!q)
+		return ERR_PTR(-ENOMEM);
+
+	rb = devm_kcalloc(dev, raw->tx_max_msg, sizeof(*rb), GFP_KERNEL);
+	if (!rb)
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock_init(&q->free_bufs_lock);
+	INIT_LIST_HEAD(&q->free_bufs);
+	for (i = 0; i < raw->tx_max_msg; i++, rb++) {
+		rb->max_len = raw->desc->max_msg_size + sizeof(u32);
+		rb->msg.buf = devm_kzalloc(dev, rb->max_len, GFP_KERNEL);
+		if (!rb->msg.buf)
+			return ERR_PTR(-ENOMEM);
+		scmi_raw_buffer_put(q, rb);
+	}
+
+	spin_lock_init(&q->msg_q_lock);
+	INIT_LIST_HEAD(&q->msg_q);
+	init_waitqueue_head(&q->wq);
+
+	return q;
+}
+
+static int scmi_xfer_raw_worker_init(struct scmi_raw_mode_info *raw)
+{
+	int i;
+	struct scmi_xfer_raw_waiter *rw;
+	struct device *dev = raw->handle->dev;
+
+	rw = devm_kcalloc(dev, raw->tx_max_msg, sizeof(*rw), GFP_KERNEL);
+	if (!rw)
+		return -ENOMEM;
+
+	raw->wait_wq = alloc_workqueue("scmi-raw-wait-wq-%d",
+				       WQ_UNBOUND | WQ_FREEZABLE |
+				       WQ_HIGHPRI, WQ_SYSFS, raw->id);
+	if (!raw->wait_wq)
+		return -ENOMEM;
+
+	mutex_init(&raw->free_mtx);
+	INIT_LIST_HEAD(&raw->free_waiters);
+	mutex_init(&raw->active_mtx);
+	INIT_LIST_HEAD(&raw->active_waiters);
+
+	for (i = 0; i < raw->tx_max_msg; i++, rw++) {
+		init_completion(&rw->async_response);
+		scmi_xfer_raw_waiter_put(raw, rw);
+	}
+	INIT_WORK(&raw->waiters_work, scmi_xfer_raw_worker);
+
+	return 0;
+}
+
+static int scmi_raw_mode_setup(struct scmi_raw_mode_info *raw)
+{
+	int ret, idx;
+	void *gid;
+	struct device *dev = raw->handle->dev;
+
+	gid = devres_open_group(dev, NULL, GFP_KERNEL);
+	if (!gid)
+		return -ENOMEM;
+
+	for (idx = 0; idx < SCMI_RAW_MAX_QUEUE; idx++) {
+		raw->q[idx] = scmi_raw_queue_init(raw);
+		if (IS_ERR(raw->q[idx])) {
+			ret = PTR_ERR(raw->q[idx]);
+			goto err;
+		}
+	}
+
+	ret = scmi_xfer_raw_worker_init(raw);
+	if (ret)
+		goto err;
+
+	devres_close_group(dev, gid);
+	raw->gid = gid;
+
+	return 0;
+
+err:
+	devres_release_group(dev, gid);
+	return ret;
+}
+
+/**
+ * scmi_raw_mode_init  - Function to initialize the SCMI Raw stack
+ *
+ * @handle: Pointer to SCMI entity handle
+ * @top_dentry: A reference to the top Raw debugfs dentry
+ * @instance_id: The ID of the underlying SCMI platform instance represented by
+ *		 this Raw instance
+ * @desc: Reference to the transport operations
+ * @tx_max_msg: Max number of in-flight messages allowed by the transport
+ *
+ * This function prepare the SCMI Raw stack and creates the debugfs API.
+ *
+ * Return: An opaque handle to the Raw instance on Success, an ERR_PTR otherwise
+ */
+void *scmi_raw_mode_init(const struct scmi_handle *handle,
+			 struct dentry *top_dentry, int instance_id,
+			 const struct scmi_desc *desc, int tx_max_msg)
+{
+	int ret;
+	struct scmi_raw_mode_info *raw;
+	struct device *dev;
+
+	if (!handle || !desc)
+		return ERR_PTR(-EINVAL);
+
+	dev = handle->dev;
+	raw = devm_kzalloc(dev, sizeof(*raw), GFP_KERNEL);
+	if (!raw)
+		return ERR_PTR(-ENOMEM);
+
+	raw->handle = handle;
+	raw->desc = desc;
+	raw->tx_max_msg = tx_max_msg;
+	raw->id = instance_id;
+
+	ret = scmi_raw_mode_setup(raw);
+	if (ret) {
+		devm_kfree(dev, raw);
+		return ERR_PTR(ret);
+	}
+
+	raw->dentry = debugfs_create_dir("raw", top_dentry);
+
+	debugfs_create_file("reset", 0200, raw->dentry, raw,
+			    &scmi_dbg_raw_mode_reset_fops);
+
+	debugfs_create_file("message", 0600, raw->dentry, raw,
+			    &scmi_dbg_raw_mode_message_fops);
+
+	debugfs_create_file("message_async", 0600, raw->dentry, raw,
+			    &scmi_dbg_raw_mode_message_async_fops);
+
+	debugfs_create_file("notification", 0400, raw->dentry, raw,
+			    &scmi_dbg_raw_mode_notification_fops);
+
+	debugfs_create_file("errors", 0400, raw->dentry, raw,
+			    &scmi_dbg_raw_mode_errors_fops);
+
+	dev_info(dev, "SCMI RAW Mode initialized for instance %d\n", raw->id);
+
+	return raw;
+}
+
+/**
+ * scmi_raw_mode_cleanup  - Function to cleanup the SCMI Raw stack
+ *
+ * @r: An opaque handle to an initialized SCMI Raw instance
+ */
+void scmi_raw_mode_cleanup(void *r)
+{
+	struct scmi_raw_mode_info *raw = r;
+
+	if (!raw)
+		return;
+
+	debugfs_remove_recursive(raw->dentry);
+
+	cancel_work_sync(&raw->waiters_work);
+	destroy_workqueue(raw->wait_wq);
+}
+
+static int scmi_xfer_raw_collect(void *msg, size_t *msg_len,
+				 struct scmi_xfer *xfer)
+{
+	__le32 *m;
+	size_t msg_size;
+
+	if (!xfer || !msg || !msg_len)
+		return -EINVAL;
+
+	/* Account for hdr ...*/
+	msg_size = xfer->rx.len + sizeof(u32);
+	/* ... and status if needed */
+	if (xfer->hdr.type != MSG_TYPE_NOTIFICATION)
+		msg_size += sizeof(u32);
+
+	if (msg_size > *msg_len)
+		return -ENOSPC;
+
+	m = msg;
+	*m = cpu_to_le32(pack_scmi_header(&xfer->hdr));
+	if (xfer->hdr.type != MSG_TYPE_NOTIFICATION)
+		*++m = cpu_to_le32(xfer->hdr.status);
+
+	memcpy(++m, xfer->rx.buf, xfer->rx.len);
+
+	*msg_len = msg_size;
+
+	return 0;
+}
+
+/**
+ * scmi_raw_message_report  - Helper to report back valid reponses/notifications
+ * to raw message requests.
+ *
+ * @r: An opaque reference to the raw instance configuration
+ * @xfer: The xfer containing the message to be reported
+ * @idx: The index of the queue.
+ *
+ * If Raw mode is enabled, this is called from the SCMI core on the regular RX
+ * path to save and enqueue the response/notification payload carried by this
+ * xfer into a dedicated scmi_raw_buffer for later consumption by the user.
+ *
+ * This way the caller can free the related xfer immediately afterwards and the
+ * user can read back the raw message payload at its own pace (if ever) without
+ * holding an xfer for too long.
+ */
+void scmi_raw_message_report(void *r, struct scmi_xfer *xfer, unsigned int idx)
+{
+	int ret;
+	unsigned long flags;
+	struct scmi_raw_buffer *rb;
+	struct device *dev;
+	struct scmi_raw_queue *q;
+	struct scmi_raw_mode_info *raw = r;
+
+	if (!raw || (idx == SCMI_RAW_REPLY_QUEUE && !SCMI_XFER_IS_RAW(xfer)))
+		return;
+
+	dev = raw->handle->dev;
+	q = raw->q[idx];
+
+	/*
+	 * Grab the msg_q_lock upfront to avoid a possible race between
+	 * realizing the free list was empty and effectively picking the next
+	 * buffer to use from the oldest one enqueued and still unread on this
+	 * msg_q.
+	 *
+	 * Note that nowhere else these locks are taken together, so no risk of
+	 * deadlocks du eto inversion.
+	 */
+	spin_lock_irqsave(&q->msg_q_lock, flags);
+	rb = scmi_raw_buffer_get(q);
+	if (!rb) {
+		/*
+		 * Immediate and delayed replies to previously injected Raw
+		 * commands MUST be read back from userspace to free the buffers:
+		 * if this is not happening something is seriously broken and
+		 * must be fixed at the application level: complain loudly.
+		 */
+		if (idx == SCMI_RAW_REPLY_QUEUE) {
+			spin_unlock_irqrestore(&q->msg_q_lock, flags);
+			dev_warn(dev,
+				 "RAW[%d] - Buffers exhausted. Dropping report.\n",
+				 idx);
+			return;
+		}
+
+		/*
+		 * Notifications and errors queues are instead handled in a
+		 * circular manner: unread old buffers are just overwritten by
+		 * newer ones.
+		 *
+		 * The main reason for this is that notifications originated
+		 * by Raw requests cannot be distinguished from normal ones, so
+		 * your Raw buffers queues risk to be flooded and depleted by
+		 * notifications if you left it mistakenly enabled or when in
+		 * coexistence mode.
+		 */
+		rb = scmi_raw_buffer_dequeue_unlocked(q);
+		if (WARN_ON(!rb)) {
+			spin_unlock_irqrestore(&q->msg_q_lock, flags);
+			return;
+		}
+
+		/* Reset to full buffer length */
+		rb->msg.len = rb->max_len;
+
+		dev_warn_once(dev,
+			      "RAW[%d] - Buffers exhausted. Re-using oldest.\n",
+			      idx);
+	}
+	spin_unlock_irqrestore(&q->msg_q_lock, flags);
+
+	ret = scmi_xfer_raw_collect(rb->msg.buf, &rb->msg.len, xfer);
+	if (ret) {
+		dev_warn(dev, "RAW - Cannot collect xfer into buffer !\n");
+		scmi_raw_buffer_put(q, rb);
+		return;
+	}
+
+	scmi_raw_buffer_enqueue(q, rb);
+}
+
+static void scmi_xfer_raw_fill(struct scmi_raw_mode_info *raw,
+			       struct scmi_chan_info *cinfo,
+			       struct scmi_xfer *xfer, u32 msg_hdr)
+{
+	/* Unpack received HDR as it is */
+	unpack_scmi_header(msg_hdr, &xfer->hdr);
+	xfer->hdr.seq = MSG_XTRACT_TOKEN(msg_hdr);
+
+	memset(xfer->rx.buf, 0x00, xfer->rx.len);
+
+	raw->desc->ops->fetch_response(cinfo, xfer);
+}
+
+/**
+ * scmi_raw_error_report  - Helper to report back timed-out or generally
+ * unexpected replies.
+ *
+ * @r: An opaque reference to the raw instance configuration
+ * @cinfo: A reference to the channel to use to retrieve the broken xfer
+ * @msg_hdr: The SCMI message header of the message to fetch and report
+ * @priv: Any private data related to the xfer.
+ *
+ * If Raw mode is enabled, this is called from the SCMI core on the RX path in
+ * case of errors to save and enqueue the bad message payload carried by the
+ * message that has just been received.
+ *
+ * Note that we have to manually fetch any available payload into a temporary
+ * xfer to be able to save and enqueue the message, since the regular RX error
+ * path which had called this would have not fetched the message payload having
+ * classified it as an error.
+ */
+void scmi_raw_error_report(void *r, struct scmi_chan_info *cinfo,
+			   u32 msg_hdr, void *priv)
+{
+	struct scmi_xfer xfer;
+	struct scmi_raw_mode_info *raw = r;
+
+	if (!raw)
+		return;
+
+	xfer.rx.len = raw->desc->max_msg_size;
+	xfer.rx.buf = kzalloc(xfer.rx.len, GFP_ATOMIC);
+	if (!xfer.rx.buf) {
+		dev_info(raw->handle->dev,
+			 "Cannot report Raw error for HDR:0x%X - ENOMEM\n",
+			 msg_hdr);
+		return;
+	}
+
+	/* Any transport-provided priv must be passed back down to transport */
+	if (priv)
+		/* Ensure priv is visible */
+		smp_store_mb(xfer.priv, priv);
+
+	scmi_xfer_raw_fill(raw, cinfo, &xfer, msg_hdr);
+	scmi_raw_message_report(raw, &xfer, SCMI_RAW_ERRS_QUEUE);
+
+	kfree(xfer.rx.buf);
+}
diff --git a/drivers/firmware/arm_scmi/raw_mode.h b/drivers/firmware/arm_scmi/raw_mode.h
new file mode 100644
index 000000000000..1e3d1660b0e4
--- /dev/null
+++ b/drivers/firmware/arm_scmi/raw_mode.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * System Control and Management Interface (SCMI) Message Protocol
+ * Raw mode support header.
+ *
+ * Copyright (C) 2022 ARM Ltd.
+ */
+#ifndef _SCMI_RAW_MODE_H
+#define _SCMI_RAW_MODE_H
+
+#include "common.h"
+
+enum {
+	SCMI_RAW_REPLY_QUEUE,
+	SCMI_RAW_NOTIF_QUEUE,
+	SCMI_RAW_ERRS_QUEUE,
+	SCMI_RAW_MAX_QUEUE
+};
+
+void *scmi_raw_mode_init(const struct scmi_handle *handle,
+			 struct dentry *top_dentry, int instance_id,
+			 const struct scmi_desc *desc, int tx_max_msg);
+void scmi_raw_mode_cleanup(void *raw);
+
+void scmi_raw_message_report(void *raw, struct scmi_xfer *xfer,
+			     unsigned int idx);
+void scmi_raw_error_report(void *raw, struct scmi_chan_info *cinfo,
+			   u32 msg_hdr, void *priv);
+
+#endif /* _SCMI_RAW_MODE_H */
-- 
2.34.1

[PATCH v8 13/17] firmware: arm_scmi: Add debugfs ABI documentation for Raw mode

[Cristian Marussi]

Add description of the debugfs SCMI Raw ABI.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v5 --> v6
- split debugfs Raw ABI doc into its own docfile and changed
  the top rootfs structure
v4 --> v5
- updated ABI description for multiple SCMI instances support
---
 Documentation/ABI/testing/debugfs-scmi-raw | 66 ++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 Documentation/ABI/testing/debugfs-scmi-raw

diff --git a/Documentation/ABI/testing/debugfs-scmi-raw b/Documentation/ABI/testing/debugfs-scmi-raw
new file mode 100644
index 000000000000..45817d465b1f
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-scmi-raw
@@ -0,0 +1,66 @@
+What:		/sys/kernel/debug/scmi/<n>/raw/message
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw synchronous message injection/snooping facility; write
+		a complete SCMI synchronous command message (header included)
+		in little-endian binary format to have it sent to the configured
+		backend SCMI server for instance <n>.
+		Any subsequently received response can be read from this same
+		entry if it arrived within the configured timeout.
+		Each write to the entry causes one command request to be built
+		and sent while the replies are read back one message at time
+		(receiving an EOF at each message boundary).
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/message_async
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw asynchronous message injection/snooping facility; write
+		a complete SCMI asynchronous command message (header included)
+		in little-endian binary format to have it sent to the configured
+		backend SCMI server for instance <n>.
+		Any subsequently received response can be read from this same
+		entry if it arrived within the configured timeout.
+		Any additional delayed response received afterwards can be read
+		from this same entry too if it arrived within the configured
+		timeout.
+		Each write to the entry causes one command request to be built
+		and sent while the replies are read back one message at time
+		(receiving an EOF at each message boundary).
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/errors
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw message errors facility; any kind of timed-out or
+		generally unexpectedly received SCMI message, for instance <n>,
+		can be read from this entry.
+		Each read gives back one message at time (receiving an EOF at
+		each message boundary).
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/notification
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw notification snooping facility; any notification
+		emitted by the backend SCMI server, for instance <n>, can be
+		read from this entry.
+		Each read gives back one message at time (receiving an EOF at
+		each message boundary).
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/reset
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw stack reset facility; writing a value to this entry
+		causes the internal queues of any kind of received message,
+		still pending to be read out for instance <n>, to be immediately
+		flushed.
+		Can be used to reset and clean the SCMI Raw stack between to
+		different test-run.
+Users:		Debugging, any userspace test suite
-- 
2.34.1

[PATCH v8 14/17] firmware: arm_scmi: Reject SCMI drivers while in Raw mode

[Cristian Marussi]

Reject SCMI driver registration when SCMI Raw mode support is configured,
so as to avoid interferences between the SCMI Raw mode transactions and the
normal SCMI stack operations.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 drivers/firmware/arm_scmi/bus.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index 6228f1581fe3..8601d75f5b9b 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -59,6 +59,12 @@ static int scmi_protocol_device_request(const struct scmi_device_id *id_table)
 	pr_debug("Requesting SCMI device (%s) for protocol %x\n",
 		 id_table->name, id_table->protocol_id);
 
+	if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
+		pr_warn("SCMI Raw mode active. Rejecting '%s'/0x%02X\n",
+			id_table->name, id_table->protocol_id);
+		return -EINVAL;
+	}
+
 	/*
 	 * Search for the matching protocol rdev list and then search
 	 * of any existent equally named device...fails if any duplicate found.
-- 
2.34.1

[PATCH v8 15/17] firmware: arm_scmi: Call Raw mode hooks from the core stack

[Cristian Marussi]

Add a few call sites where, if SCMI Raw mode access had been enabled in
Kconfig, the needed SCMI Raw initialization and hooks are called.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v7 --> v8
- refactor RAw mode initialization
v5 --> v6
- fix error path for RAW mode in scmi_probe
- use new debugfs Raw rootdir
v4 --> v5
- rework to use multiple SCMI instances
v3 --> v4
- add call hooks to support polled transports
v1 --> v2
- fixes need to use multiple cinfo if available
---
 drivers/firmware/arm_scmi/driver.c | 63 ++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 2b96d9c3489d..ad4e53f0c342 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -37,6 +37,8 @@
 #include "common.h"
 #include "notify.h"
 
+#include "raw_mode.h"
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/scmi.h>
 
@@ -150,6 +152,7 @@ struct scmi_debug_info {
  *		bus
  * @devreq_mtx: A mutex to serialize device creation for this SCMI instance
  * @dbg: A pointer to debugfs related data (if any)
+ * @raw: An opaque reference handle used by SCMI Raw mode.
  */
 struct scmi_info {
 	int id;
@@ -175,6 +178,7 @@ struct scmi_info {
 	/* Serialize device creation process for this instance */
 	struct mutex devreq_mtx;
 	struct scmi_debug_info *dbg;
+	void *raw;
 };
 
 #define handle_to_scmi_info(h)	container_of(h, struct scmi_info, handle)
@@ -890,6 +894,11 @@ static void scmi_handle_notification(struct scmi_chan_info *cinfo,
 			   xfer->hdr.protocol_id, xfer->hdr.seq,
 			   MSG_TYPE_NOTIFICATION);
 
+	if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
+		xfer->hdr.seq = MSG_XTRACT_TOKEN(msg_hdr);
+		scmi_raw_message_report(info->raw, xfer, SCMI_RAW_NOTIF_QUEUE);
+	}
+
 	__scmi_xfer_put(minfo, xfer);
 
 	scmi_clear_channel(info, cinfo);
@@ -903,6 +912,9 @@ static void scmi_handle_response(struct scmi_chan_info *cinfo,
 
 	xfer = scmi_xfer_command_acquire(cinfo, msg_hdr);
 	if (IS_ERR(xfer)) {
+		if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT))
+			scmi_raw_error_report(info->raw, cinfo, msg_hdr, priv);
+
 		if (MSG_XTRACT_TYPE(msg_hdr) == MSG_TYPE_DELAYED_RESP)
 			scmi_clear_channel(info, cinfo);
 		return;
@@ -936,6 +948,16 @@ static void scmi_handle_response(struct scmi_chan_info *cinfo,
 		complete(&xfer->done);
 	}
 
+	if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
+		/*
+		 * When in polling mode avoid to queue the Raw xfer on the IRQ
+		 * RX path since it will be already queued at the end of the TX
+		 * poll loop.
+		 */
+		if (!xfer->hdr.poll_completion)
+			scmi_raw_message_report(info->raw, xfer, SCMI_RAW_REPLY_QUEUE);
+	}
+
 	scmi_xfer_command_release(info, xfer);
 }
 
@@ -1050,6 +1072,14 @@ static int scmi_wait_for_reply(struct device *dev, const struct scmi_desc *desc,
 					    "RESP" : "resp",
 					    xfer->hdr.seq, xfer->hdr.status,
 					    xfer->rx.buf, xfer->rx.len);
+
+			if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
+				struct scmi_info *info =
+					handle_to_scmi_info(cinfo->handle);
+
+				scmi_raw_message_report(info->raw, xfer,
+							SCMI_RAW_REPLY_QUEUE);
+			}
 		}
 	} else {
 		/* And we wait for the response. */
@@ -2576,6 +2606,26 @@ static struct scmi_debug_info *scmi_debugfs_common_setup(struct scmi_info *info)
 	return dbg;
 }
 
+static int scmi_debugfs_raw_mode_setup(struct scmi_info *info)
+{
+	int ret = 0;
+
+	if (!info->dbg)
+		return -EINVAL;
+
+	info->raw = scmi_raw_mode_init(&info->handle, info->dbg->top_dentry,
+				       info->id, info->desc,
+				       info->tx_minfo.max_msg);
+
+	if (IS_ERR(info->raw)) {
+		dev_err(info->dev, "Failed to initialize SCMI RAW Mode !\n");
+		ret = PTR_ERR(info->raw);
+		info->raw = NULL;
+	}
+
+	return ret;
+}
+
 static int scmi_probe(struct platform_device *pdev)
 {
 	int ret;
@@ -2654,6 +2704,14 @@ static int scmi_probe(struct platform_device *pdev)
 		info->dbg = scmi_debugfs_common_setup(info);
 		if (!info->dbg)
 			dev_warn(dev, "Failed to setup SCMI debugfs.\n");
+
+		if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
+			ret = scmi_debugfs_raw_mode_setup(info);
+			if (ret)
+				goto clear_dev_req_notifier;
+
+			return 0;
+		}
 	}
 
 	if (scmi_notification_init(handle))
@@ -2713,6 +2771,8 @@ static int scmi_probe(struct platform_device *pdev)
 	return 0;
 
 notification_exit:
+	if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT))
+		scmi_raw_mode_cleanup(info->raw);
 	scmi_notification_exit(&info->handle);
 clear_dev_req_notifier:
 	blocking_notifier_chain_unregister(&scmi_requested_devices_nh,
@@ -2732,6 +2792,9 @@ static int scmi_remove(struct platform_device *pdev)
 	struct scmi_info *info = platform_get_drvdata(pdev);
 	struct device_node *child;
 
+	if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT))
+		scmi_raw_mode_cleanup(info->raw);
+
 	mutex_lock(&scmi_list_mutex);
 	if (info->users)
 		dev_warn(&pdev->dev,
-- 
2.34.1

[PATCH v8 16/17] firmware: arm_scmi: Add Raw mode coexistence support

[Cristian Marussi]

When Raw support is enabled and configured in coexistence mode the normal
SCMI drivers are allowed to register with the SCMI core and operate as
usual alongside the Raw operations.

SCMI Normal and Raw messages will be kept segregated from each other, but
only at the transaction level: any further possible interference at the
protocol layer will have instead to be handled by the user to attain
reliable results while using Raw transactions.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v7 --> v8
- refactor to fit new scmi_debugfs_raw_mode_setup helper
v5 --> v6
- fix error path for RAW Coex on scmi_probe
---
 drivers/firmware/arm_scmi/Kconfig    | 10 ++++++++++
 drivers/firmware/arm_scmi/bus.c      |  3 ++-
 drivers/firmware/arm_scmi/driver.c   | 16 ++++++++++++----
 drivers/firmware/arm_scmi/raw_mode.c |  5 ++++-
 4 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/drivers/firmware/arm_scmi/Kconfig b/drivers/firmware/arm_scmi/Kconfig
index 3b4f9e92b1e3..ea0f5083ac47 100644
--- a/drivers/firmware/arm_scmi/Kconfig
+++ b/drivers/firmware/arm_scmi/Kconfig
@@ -45,6 +45,16 @@ config ARM_SCMI_RAW_MODE_SUPPORT
 	  order to avoid unexpected interactions with the SCMI Raw message
 	  flow. If unsure say N.
 
+config ARM_SCMI_RAW_MODE_SUPPORT_COEX
+	bool "Allow SCMI Raw mode coexistence with normal SCMI stack"
+	depends on ARM_SCMI_RAW_MODE_SUPPORT
+	help
+	  Allow SCMI Raw transmission mode to coexist with normal SCMI stack.
+
+	  This will allow regular SCMI drivers to register with the core and
+	  operate normally, thing which could make an SCMI test suite using the
+	  SCMI Raw mode support unreliable. If unsure, say N.
+
 config ARM_SCMI_HAVE_TRANSPORT
 	bool
 	help
diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index 8601d75f5b9b..68cc4b4290c1 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -59,7 +59,8 @@ static int scmi_protocol_device_request(const struct scmi_device_id *id_table)
 	pr_debug("Requesting SCMI device (%s) for protocol %x\n",
 		 id_table->name, id_table->protocol_id);
 
-	if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
+	if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT) &&
+	    !IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT_COEX)) {
 		pr_warn("SCMI Raw mode active. Rejecting '%s'/0x%02X\n",
 			id_table->name, id_table->protocol_id);
 		return -EINVAL;
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index ad4e53f0c342..282d7737cb8f 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -2616,7 +2616,6 @@ static int scmi_debugfs_raw_mode_setup(struct scmi_info *info)
 	info->raw = scmi_raw_mode_init(&info->handle, info->dbg->top_dentry,
 				       info->id, info->desc,
 				       info->tx_minfo.max_msg);
-
 	if (IS_ERR(info->raw)) {
 		dev_err(info->dev, "Failed to initialize SCMI RAW Mode !\n");
 		ret = PTR_ERR(info->raw);
@@ -2706,11 +2705,20 @@ static int scmi_probe(struct platform_device *pdev)
 			dev_warn(dev, "Failed to setup SCMI debugfs.\n");
 
 		if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
+			bool coex =
+			      IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT_COEX);
+
 			ret = scmi_debugfs_raw_mode_setup(info);
-			if (ret)
-				goto clear_dev_req_notifier;
+			if (!coex) {
+				if (ret)
+					goto clear_dev_req_notifier;
+
+				/* Bail out anyway when coex enabled */
+				return ret;
+			}
 
-			return 0;
+			/* Coex enabled, carry on in any case. */
+			dev_info(dev, "SCMI RAW Mode COEX enabled !\n");
 		}
 	}
 
diff --git a/drivers/firmware/arm_scmi/raw_mode.c b/drivers/firmware/arm_scmi/raw_mode.c
index a33ef0eaffe5..037ef9c14fae 100644
--- a/drivers/firmware/arm_scmi/raw_mode.c
+++ b/drivers/firmware/arm_scmi/raw_mode.c
@@ -26,7 +26,10 @@
  * In order to avoid possible interferences between the SCMI Raw transactions
  * originated from a test-suite and the normal operations of the SCMI drivers,
  * when Raw mode is enabled, by default, all the regular SCMI drivers are
- * inhibited.
+ * inhibited, unless CONFIG_ARM_SCMI_RAW_MODE_SUPPORT_COEX is enabled: in this
+ * latter case the regular SCMI stack drivers will be loaded as usual and it is
+ * up to the user of this interface to take care of manually inhibiting the
+ * regular SCMI drivers in order to avoid interferences during the test runs.
  *
  * The exposed API is as follows.
  *
-- 
2.34.1

[PATCH v8 17/17] firmware: arm_scmi: Add per-channel Raw injection support

[Cristian Marussi]

On a system configured with multiple transport channels, expose a few
additional debugfs per-channel entries to allow a user to explicitly select
which transport channel to use for the SCMI message injection.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
v7 --> v8
- use Xarray instead of per-channel IDR
- refactor to fit new scmi_debugfs_raw_mode_setup helper
- Fixed error path while handling channels queues
Reported-by: Dan Carpenter <error27@gmail.com>

v6 -> v7
- remove info channels/num_chans fields since uneeded, gather
  such data dynamically
---
 Documentation/ABI/testing/debugfs-scmi-raw |  43 ++++++
 drivers/firmware/arm_scmi/common.h         |   2 +
 drivers/firmware/arm_scmi/driver.c         |  38 +++++-
 drivers/firmware/arm_scmi/protocols.h      |   3 +
 drivers/firmware/arm_scmi/raw_mode.c       | 152 ++++++++++++++++++---
 drivers/firmware/arm_scmi/raw_mode.h       |   3 +-
 6 files changed, 217 insertions(+), 24 deletions(-)

diff --git a/Documentation/ABI/testing/debugfs-scmi-raw b/Documentation/ABI/testing/debugfs-scmi-raw
index 45817d465b1f..5468ec08c084 100644
--- a/Documentation/ABI/testing/debugfs-scmi-raw
+++ b/Documentation/ABI/testing/debugfs-scmi-raw
@@ -64,3 +64,46 @@ Description:	SCMI Raw stack reset facility; writing a value to this entry
 		Can be used to reset and clean the SCMI Raw stack between to
 		different test-run.
 Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/channels/<m>/message
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw synchronous message injection/snooping facility; write
+		a complete SCMI synchronous command message (header included)
+		in little-endian binary format to have it sent to the configured
+		backend SCMI server for instance <n> through the <m> transport
+		channel.
+		Any subsequently received response can be read from this same
+		entry if it arrived on channel <m> within the configured
+		timeout.
+		Each write to the entry causes one command request to be built
+		and sent while the replies are read back one message at time
+		(receiving an EOF at each message boundary).
+		Note that these per-channel entries rooted at <..>/channels
+		exist only if the transport is configured to have more than
+		one channel.
+Users:		Debugging, any userspace test suite
+
+What:		/sys/kernel/debug/scmi/<n>/raw/channels/<m>/message_async
+Date:		March 2023
+KernelVersion:	6.3
+Contact:	cristian.marussi@arm.com
+Description:	SCMI Raw asynchronous message injection/snooping facility; write
+		a complete SCMI asynchronous command message (header included)
+		in little-endian binary format to have it sent to the configured
+		backend SCMI server for instance <n> through the <m> transport
+		channel.
+		Any subsequently received response can be read from this same
+		entry if it arrived on channel <m> within the configured
+		timeout.
+		Any additional delayed response received afterwards can be read
+		from this same entry too if it arrived within the configured
+		timeout.
+		Each write to the entry causes one command request to be built
+		and sent while the replies are read back one message at time
+		(receiving an EOF at each message boundary).
+		Note that these per-channel entries rooted at <..>/channels
+		exist only if the transport is configured to have more than
+		one channel.
+Users:		Debugging, any userspace test suite
diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index bf3883f169e3..c46dc5215af7 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -27,6 +27,8 @@
 #include "protocols.h"
 #include "notify.h"
 
+#define SCMI_MAX_CHANNELS		256
+
 #define SCMI_MAX_RESPONSE_TIMEOUT	(2 * MSEC_PER_SEC)
 
 enum scmi_error_codes {
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 282d7737cb8f..d21c7eafd641 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -660,6 +660,7 @@ void scmi_xfer_raw_put(const struct scmi_handle *handle, struct scmi_xfer *xfer)
 	struct scmi_info *info = handle_to_scmi_info(handle);
 
 	xfer->flags &= ~SCMI_XFER_FLAG_IS_RAW;
+	xfer->flags &= ~SCMI_XFER_FLAG_CHAN_SET;
 	return __scmi_xfer_put(&info->tx_minfo, xfer);
 }
 
@@ -896,7 +897,8 @@ static void scmi_handle_notification(struct scmi_chan_info *cinfo,
 
 	if (IS_ENABLED(CONFIG_ARM_SCMI_RAW_MODE_SUPPORT)) {
 		xfer->hdr.seq = MSG_XTRACT_TOKEN(msg_hdr);
-		scmi_raw_message_report(info->raw, xfer, SCMI_RAW_NOTIF_QUEUE);
+		scmi_raw_message_report(info->raw, xfer, SCMI_RAW_NOTIF_QUEUE,
+					cinfo->id);
 	}
 
 	__scmi_xfer_put(minfo, xfer);
@@ -955,7 +957,9 @@ static void scmi_handle_response(struct scmi_chan_info *cinfo,
 		 * poll loop.
 		 */
 		if (!xfer->hdr.poll_completion)
-			scmi_raw_message_report(info->raw, xfer, SCMI_RAW_REPLY_QUEUE);
+			scmi_raw_message_report(info->raw, xfer,
+						SCMI_RAW_REPLY_QUEUE,
+						cinfo->id);
 	}
 
 	scmi_xfer_command_release(info, xfer);
@@ -1078,7 +1082,8 @@ static int scmi_wait_for_reply(struct device *dev, const struct scmi_desc *desc,
 					handle_to_scmi_info(cinfo->handle);
 
 				scmi_raw_message_report(info->raw, xfer,
-							SCMI_RAW_REPLY_QUEUE);
+							SCMI_RAW_REPLY_QUEUE,
+							cinfo->id);
 			}
 		}
 	} else {
@@ -2608,14 +2613,35 @@ static struct scmi_debug_info *scmi_debugfs_common_setup(struct scmi_info *info)
 
 static int scmi_debugfs_raw_mode_setup(struct scmi_info *info)
 {
-	int ret = 0;
+	int id, num_chans = 0, ret = 0;
+	struct scmi_chan_info *cinfo;
+	u8 channels[SCMI_MAX_CHANNELS] = {};
+	DECLARE_BITMAP(protos, SCMI_MAX_CHANNELS) = {};
 
 	if (!info->dbg)
 		return -EINVAL;
 
+	/* Enumerate all channels to collect their ids */
+	idr_for_each_entry(&info->tx_idr, cinfo, id) {
+		/*
+		 * Cannot happen, but be defensive.
+		 * Zero as num_chans is ok, warn and carry on.
+		 */
+		if (num_chans >= SCMI_MAX_CHANNELS || !cinfo) {
+			dev_warn(info->dev,
+				 "SCMI RAW - Error enumerating channels\n");
+			break;
+		}
+
+		if (!test_bit(cinfo->id, protos)) {
+			channels[num_chans++] = cinfo->id;
+			set_bit(cinfo->id, protos);
+		}
+	}
+
 	info->raw = scmi_raw_mode_init(&info->handle, info->dbg->top_dentry,
-				       info->id, info->desc,
-				       info->tx_minfo.max_msg);
+				       info->id, channels, num_chans,
+				       info->desc, info->tx_minfo.max_msg);
 	if (IS_ERR(info->raw)) {
 		dev_err(info->dev, "Failed to initialize SCMI RAW Mode !\n");
 		ret = PTR_ERR(info->raw);
diff --git a/drivers/firmware/arm_scmi/protocols.h b/drivers/firmware/arm_scmi/protocols.h
index b5941beb8b03..78e1a01eb656 100644
--- a/drivers/firmware/arm_scmi/protocols.h
+++ b/drivers/firmware/arm_scmi/protocols.h
@@ -138,6 +138,9 @@ struct scmi_xfer {
 	int state;
 #define SCMI_XFER_FLAG_IS_RAW	BIT(0)
 #define SCMI_XFER_IS_RAW(x)	((x)->flags & SCMI_XFER_FLAG_IS_RAW)
+#define SCMI_XFER_FLAG_CHAN_SET	BIT(1)
+#define SCMI_XFER_IS_CHAN_SET(x)	\
+	((x)->flags & SCMI_XFER_FLAG_CHAN_SET)
 	int flags;
 	/* A lock to protect state and busy fields */
 	spinlock_t lock;
diff --git a/drivers/firmware/arm_scmi/raw_mode.c b/drivers/firmware/arm_scmi/raw_mode.c
index 037ef9c14fae..d40df099fd51 100644
--- a/drivers/firmware/arm_scmi/raw_mode.c
+++ b/drivers/firmware/arm_scmi/raw_mode.c
@@ -37,10 +37,17 @@
  * which in turn is rooted under the corresponding underlying  SCMI instance.
  *
  * /sys/kernel/debug/scmi/
- * |-- 0
+ * `-- 0
  *     |-- atomic_threshold_us
  *     |-- instance_name
  *     |-- raw
+ *     |   |-- channels
+ *     |   |   |-- 0x10
+ *     |   |   |   |-- message
+ *     |   |   |   `-- message_async
+ *     |   |   `-- 0x13
+ *     |   |       |-- message
+ *     |   |       `-- message_async
  *     |   |-- errors
  *     |   |-- message
  *     |   |-- message_async
@@ -65,6 +72,15 @@
  *	     to be read; this is useful at test-suite start/stop to get
  *	     rid of any unread messages from the previous run.
  *
+ * with the per-channel entries rooted at /channels being present only on a
+ * system where multiple transport channels have been configured.
+ *
+ * Such per-channel entries can be used to explicitly choose a specific channel
+ * for SCMI bare message injection, in contrast with the general entries above
+ * where, instead, the selection of the proper channel to use is automatically
+ * performed based the protocol embedded in the injected message and on how the
+ * transport is configured on the system.
+ *
  * Note that other common general entries are available under transport/ to let
  * the user applications properly make up their expectations in terms of
  * timeouts and message characteristics.
@@ -95,7 +111,6 @@
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/export.h>
-#include <linux/idr.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/fs.h>
@@ -104,6 +119,7 @@
 #include <linux/poll.h>
 #include <linux/of.h>
 #include <linux/slab.h>
+#include <linux/xarray.h>
 
 #include "common.h"
 
@@ -140,6 +156,7 @@ struct scmi_raw_queue {
  * @desc: Pointer to the transport descriptor to use
  * @tx_max_msg: Maximum number of concurrent TX in-flight messages
  * @q: An array of Raw queue descriptors
+ * @chans_q: An XArray mapping optional additional per-channel queues
  * @free_waiters: Head of freelist for unused waiters
  * @free_mtx: A mutex to protect the waiters freelist
  * @active_waiters: Head of list for currently active and used waiters
@@ -159,6 +176,7 @@ struct scmi_raw_mode_info {
 	const struct scmi_desc *desc;
 	int tx_max_msg;
 	struct scmi_raw_queue *q[SCMI_RAW_MAX_QUEUE];
+	struct xarray chans_q;
 	struct list_head free_waiters;
 	/* Protect free_waiters list */
 	struct mutex free_mtx;
@@ -208,6 +226,8 @@ struct scmi_raw_buffer {
  * struct scmi_dbg_raw_data  - Structure holding data needed by the debugfs
  * layer
  *
+ * @chan_id: The preferred channel to use: if zero the channel is automatically
+ *	     selected based on protocol.
  * @raw: A reference to the Raw instance.
  * @tx: A message buffer used to collect TX message on write.
  * @tx_size: The effective size of the TX message.
@@ -216,6 +236,7 @@ struct scmi_raw_buffer {
  * @rx_size: The effective size of the RX message.
  */
 struct scmi_dbg_raw_data {
+	u8 chan_id;
 	struct scmi_raw_mode_info *raw;
 	struct scmi_msg tx;
 	size_t tx_size;
@@ -224,6 +245,16 @@ struct scmi_dbg_raw_data {
 	size_t rx_size;
 };
 
+static struct scmi_raw_queue *
+scmi_raw_queue_select(struct scmi_raw_mode_info *raw, unsigned int idx,
+		      unsigned int chan_id)
+{
+	if (!chan_id)
+		return raw->q[idx];
+
+	return xa_load(&raw->chans_q, chan_id);
+}
+
 static struct scmi_raw_buffer *scmi_raw_buffer_get(struct scmi_raw_queue *q)
 {
 	unsigned long flags;
@@ -563,6 +594,8 @@ static int scmi_xfer_raw_get_init(struct scmi_raw_mode_info *raw, void *buf,
  *
  * @raw: A reference to the Raw instance.
  * @xfer: The xfer to send
+ * @chan_id: The channel ID to use, if zero the channels is automatically
+ *	     selected based on the protocol used.
  * @async: A flag stating if an asynchronous command is required.
  *
  * This function send a previously built raw xfer using an appropriate channel
@@ -576,14 +609,20 @@ static int scmi_xfer_raw_get_init(struct scmi_raw_mode_info *raw, void *buf,
  * Return: 0 on Success
  */
 static int scmi_do_xfer_raw_start(struct scmi_raw_mode_info *raw,
-				  struct scmi_xfer *xfer, bool async)
+				  struct scmi_xfer *xfer, u8 chan_id,
+				  bool async)
 {
 	int ret;
 	struct scmi_chan_info *cinfo;
 	struct scmi_xfer_raw_waiter *rw;
 	struct device *dev = raw->handle->dev;
 
-	cinfo = scmi_xfer_raw_channel_get(raw->handle, xfer->hdr.protocol_id);
+	if (!chan_id)
+		chan_id = xfer->hdr.protocol_id;
+	else
+		xfer->flags |= SCMI_XFER_FLAG_CHAN_SET;
+
+	cinfo = scmi_xfer_raw_channel_get(raw->handle, chan_id);
 	if (IS_ERR(cinfo))
 		return PTR_ERR(cinfo);
 
@@ -630,12 +669,13 @@ static int scmi_do_xfer_raw_start(struct scmi_raw_mode_info *raw,
  * @buf: A buffer containing the whole SCMI message to send (including the
  *	 header) in little-endian binary format.
  * @len: Length of the message in @buf.
+ * @chan_id: The channel ID to use.
  * @async: A flag stating if an asynchronous command is required.
  *
  * Return: 0 on Success
  */
 static int scmi_raw_message_send(struct scmi_raw_mode_info *raw,
-				 void *buf, size_t len, bool async)
+				 void *buf, size_t len, u8 chan_id, bool async)
 {
 	int ret;
 	struct scmi_xfer *xfer;
@@ -644,7 +684,7 @@ static int scmi_raw_message_send(struct scmi_raw_mode_info *raw,
 	if (ret)
 		return ret;
 
-	ret = scmi_do_xfer_raw_start(raw, xfer, async);
+	ret = scmi_do_xfer_raw_start(raw, xfer, chan_id, async);
 	if (ret)
 		scmi_xfer_raw_put(raw->handle, xfer);
 
@@ -687,18 +727,23 @@ scmi_raw_message_dequeue(struct scmi_raw_queue *q, bool o_nonblock)
  * @len: Length of @buf.
  * @size: The effective size of the message copied into @buf
  * @idx: The index of the queue to pick the next queued message from.
+ * @chan_id: The channel ID to use.
  * @o_nonblock: A flag to request a non-blocking message dequeue.
  *
  * Return: 0 on Success
  */
 static int scmi_raw_message_receive(struct scmi_raw_mode_info *raw,
 				    void *buf, size_t len, size_t *size,
-				    unsigned int idx,
+				    unsigned int idx, unsigned int chan_id,
 				    bool o_nonblock)
 {
 	int ret = 0;
 	struct scmi_raw_buffer *rb;
-	struct scmi_raw_queue *q = raw->q[idx];
+	struct scmi_raw_queue *q;
+
+	q = scmi_raw_queue_select(raw, idx, chan_id);
+	if (!q)
+		return -ENODEV;
 
 	rb = scmi_raw_message_dequeue(q, o_nonblock);
 	if (IS_ERR(rb)) {
@@ -732,7 +777,7 @@ static ssize_t scmi_dbg_raw_mode_common_read(struct file *filp,
 		int ret;
 
 		ret = scmi_raw_message_receive(rd->raw, rd->rx.buf, rd->rx.len,
-					       &rd->rx_size, idx,
+					       &rd->rx_size, idx, rd->chan_id,
 					       filp->f_flags & O_NONBLOCK);
 		if (ret) {
 			rd->rx_size = 0;
@@ -782,7 +827,8 @@ static ssize_t scmi_dbg_raw_mode_common_write(struct file *filp,
 			return cnt;
 	}
 
-	ret = scmi_raw_message_send(rd->raw, rd->tx.buf, rd->tx_size, async);
+	ret = scmi_raw_message_send(rd->raw, rd->tx.buf, rd->tx_size,
+				    rd->chan_id, async);
 
 	/* Reset ppos for next message ... */
 	rd->tx_size = 0;
@@ -797,9 +843,13 @@ static __poll_t scmi_test_dbg_raw_common_poll(struct file *filp,
 {
 	unsigned long flags;
 	struct scmi_dbg_raw_data *rd = filp->private_data;
-	struct scmi_raw_queue *q = rd->raw->q[idx];
+	struct scmi_raw_queue *q;
 	__poll_t mask = 0;
 
+	q = scmi_raw_queue_select(rd->raw, idx, rd->chan_id);
+	if (!q)
+		return mask;
+
 	poll_wait(filp, &q->wq, wait);
 
 	spin_lock_irqsave(&q->msg_q_lock, flags);
@@ -833,8 +883,10 @@ static __poll_t scmi_dbg_raw_mode_message_poll(struct file *filp,
 
 static int scmi_dbg_raw_mode_open(struct inode *inode, struct file *filp)
 {
+	u8 id;
 	struct scmi_raw_mode_info *raw;
 	struct scmi_dbg_raw_data *rd;
+	const char *id_str = filp->f_path.dentry->d_parent->d_name.name;
 
 	if (!inode->i_private)
 		return -ENODEV;
@@ -859,6 +911,10 @@ static int scmi_dbg_raw_mode_open(struct inode *inode, struct file *filp)
 		return -ENOMEM;
 	}
 
+	/* Grab channel ID from debugfs entry naming if any */
+	if (!kstrtou8(id_str, 16, &id))
+		rd->chan_id = id;
+
 	rd->raw = raw;
 	filp->private_data = rd;
 
@@ -1028,7 +1084,8 @@ static int scmi_xfer_raw_worker_init(struct scmi_raw_mode_info *raw)
 	return 0;
 }
 
-static int scmi_raw_mode_setup(struct scmi_raw_mode_info *raw)
+static int scmi_raw_mode_setup(struct scmi_raw_mode_info *raw,
+			       u8 *channels, int num_chans)
 {
 	int ret, idx;
 	void *gid;
@@ -1046,15 +1103,43 @@ static int scmi_raw_mode_setup(struct scmi_raw_mode_info *raw)
 		}
 	}
 
+	xa_init(&raw->chans_q);
+	if (num_chans > 1) {
+		int i;
+
+		for (i = 0; i < num_chans; i++) {
+			void *xret;
+			struct scmi_raw_queue *q;
+
+			q = scmi_raw_queue_init(raw);
+			if (IS_ERR(q)) {
+				ret = PTR_ERR(q);
+				goto err_xa;
+			}
+
+			xret = xa_store(&raw->chans_q, channels[i], q,
+					GFP_KERNEL);
+			if (xa_err(xret)) {
+				dev_err(dev,
+					"Fail to allocate Raw queue 0x%02X\n",
+					channels[i]);
+				ret = xa_err(xret);
+				goto err_xa;
+			}
+		}
+	}
+
 	ret = scmi_xfer_raw_worker_init(raw);
 	if (ret)
-		goto err;
+		goto err_xa;
 
 	devres_close_group(dev, gid);
 	raw->gid = gid;
 
 	return 0;
 
+err_xa:
+	xa_destroy(&raw->chans_q);
 err:
 	devres_release_group(dev, gid);
 	return ret;
@@ -1067,6 +1152,8 @@ static int scmi_raw_mode_setup(struct scmi_raw_mode_info *raw)
  * @top_dentry: A reference to the top Raw debugfs dentry
  * @instance_id: The ID of the underlying SCMI platform instance represented by
  *		 this Raw instance
+ * @channels: The list of the existing channels
+ * @num_chans: The number of entries in @channels
  * @desc: Reference to the transport operations
  * @tx_max_msg: Max number of in-flight messages allowed by the transport
  *
@@ -1076,6 +1163,7 @@ static int scmi_raw_mode_setup(struct scmi_raw_mode_info *raw)
  */
 void *scmi_raw_mode_init(const struct scmi_handle *handle,
 			 struct dentry *top_dentry, int instance_id,
+			 u8 *channels, int num_chans,
 			 const struct scmi_desc *desc, int tx_max_msg)
 {
 	int ret;
@@ -1095,7 +1183,7 @@ void *scmi_raw_mode_init(const struct scmi_handle *handle,
 	raw->tx_max_msg = tx_max_msg;
 	raw->id = instance_id;
 
-	ret = scmi_raw_mode_setup(raw);
+	ret = scmi_raw_mode_setup(raw, channels, num_chans);
 	if (ret) {
 		devm_kfree(dev, raw);
 		return ERR_PTR(ret);
@@ -1118,6 +1206,32 @@ void *scmi_raw_mode_init(const struct scmi_handle *handle,
 	debugfs_create_file("errors", 0400, raw->dentry, raw,
 			    &scmi_dbg_raw_mode_errors_fops);
 
+	/*
+	 * Expose per-channel entries if multiple channels available.
+	 * Just ignore errors while setting up these interfaces since we
+	 * have anyway already a working core Raw support.
+	 */
+	if (num_chans > 1) {
+		int i;
+		struct dentry *top_chans;
+
+		top_chans = debugfs_create_dir("channels", raw->dentry);
+
+		for (i = 0; i < num_chans; i++) {
+			char cdir[8];
+			struct dentry *chd;
+
+			snprintf(cdir, 8, "0x%02X", channels[i]);
+			chd = debugfs_create_dir(cdir, top_chans);
+
+			debugfs_create_file("message", 0600, chd, raw,
+					    &scmi_dbg_raw_mode_message_fops);
+
+			debugfs_create_file("message_async", 0600, chd, raw,
+					    &scmi_dbg_raw_mode_message_async_fops);
+		}
+	}
+
 	dev_info(dev, "SCMI RAW Mode initialized for instance %d\n", raw->id);
 
 	return raw;
@@ -1139,6 +1253,7 @@ void scmi_raw_mode_cleanup(void *r)
 
 	cancel_work_sync(&raw->waiters_work);
 	destroy_workqueue(raw->wait_wq);
+	xa_destroy(&raw->chans_q);
 }
 
 static int scmi_xfer_raw_collect(void *msg, size_t *msg_len,
@@ -1178,6 +1293,7 @@ static int scmi_xfer_raw_collect(void *msg, size_t *msg_len,
  * @r: An opaque reference to the raw instance configuration
  * @xfer: The xfer containing the message to be reported
  * @idx: The index of the queue.
+ * @chan_id: The channel ID to use.
  *
  * If Raw mode is enabled, this is called from the SCMI core on the regular RX
  * path to save and enqueue the response/notification payload carried by this
@@ -1187,7 +1303,8 @@ static int scmi_xfer_raw_collect(void *msg, size_t *msg_len,
  * user can read back the raw message payload at its own pace (if ever) without
  * holding an xfer for too long.
  */
-void scmi_raw_message_report(void *r, struct scmi_xfer *xfer, unsigned int idx)
+void scmi_raw_message_report(void *r, struct scmi_xfer *xfer,
+			     unsigned int idx, unsigned int chan_id)
 {
 	int ret;
 	unsigned long flags;
@@ -1200,7 +1317,8 @@ void scmi_raw_message_report(void *r, struct scmi_xfer *xfer, unsigned int idx)
 		return;
 
 	dev = raw->handle->dev;
-	q = raw->q[idx];
+	q = scmi_raw_queue_select(raw, idx,
+				  SCMI_XFER_IS_CHAN_SET(xfer) ? chan_id : 0);
 
 	/*
 	 * Grab the msg_q_lock upfront to avoid a possible race between
@@ -1319,7 +1437,7 @@ void scmi_raw_error_report(void *r, struct scmi_chan_info *cinfo,
 		smp_store_mb(xfer.priv, priv);
 
 	scmi_xfer_raw_fill(raw, cinfo, &xfer, msg_hdr);
-	scmi_raw_message_report(raw, &xfer, SCMI_RAW_ERRS_QUEUE);
+	scmi_raw_message_report(raw, &xfer, SCMI_RAW_ERRS_QUEUE, 0);
 
 	kfree(xfer.rx.buf);
 }
diff --git a/drivers/firmware/arm_scmi/raw_mode.h b/drivers/firmware/arm_scmi/raw_mode.h
index 1e3d1660b0e4..8af756a83fd1 100644
--- a/drivers/firmware/arm_scmi/raw_mode.h
+++ b/drivers/firmware/arm_scmi/raw_mode.h
@@ -19,11 +19,12 @@ enum {
 
 void *scmi_raw_mode_init(const struct scmi_handle *handle,
 			 struct dentry *top_dentry, int instance_id,
+			 u8 *channels, int num_chans,
 			 const struct scmi_desc *desc, int tx_max_msg);
 void scmi_raw_mode_cleanup(void *raw);
 
 void scmi_raw_message_report(void *raw, struct scmi_xfer *xfer,
-			     unsigned int idx);
+			     unsigned int idx, unsigned int chan_id);
 void scmi_raw_error_report(void *raw, struct scmi_chan_info *cinfo,
 			   u32 msg_hdr, void *priv);
 
-- 
2.34.1

Re: [PATCH v8 09/17] debugfs: Export debugfs_create_str symbol

[Greg Kroah-Hartman]

On Wed, Jan 18, 2023 at 12:14:18PM +0000, Cristian Marussi wrote:
> Needed by SCMI Raw mode support when compiled as a loadable module.
> 
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
> Used by the following patch in this series:
> 
> "firmware: arm_scmi: Populate a common SCMI debugsfs root"
> 
> SCMI stack can be configured as module so export is needed.
> ---
>  fs/debugfs/file.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
> index b54f470e0d03..1f971c880dde 100644
> --- a/fs/debugfs/file.c
> +++ b/fs/debugfs/file.c
> @@ -899,6 +899,7 @@ ssize_t debugfs_read_file_str(struct file *file, char __user *user_buf,
>  
>  	return ret;
>  }
> +EXPORT_SYMBOL_GPL(debugfs_create_str);
>  
>  static ssize_t debugfs_write_file_str(struct file *file, const char __user *user_buf,
>  				      size_t count, loff_t *ppos)
> -- 
> 2.34.1
> 

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Re: [PATCH v8 00/17] Introduce a unified API for SCMI Server testing

[Sudeep Holla]

On Wed, 18 Jan 2023 12:14:09 +0000, Cristian Marussi wrote:
> This series aims to introduce a new SCMI unified userspace interface meant
> to ease testing an SCMI Server implementation for compliance, fuzzing etc.,
> from the perspective of the OSPM agent (non-secure world only ...)
> 
> It is proposed as a testing/development facility, it is NOT meant to be a
> feature to use in production, but only enabled in Kconfig for test
> deployments.
> 
> [...]

Applied to sudeep.holla/linux (for-next/scmi), thanks!

[01/17] firmware: arm_scmi: Refactor xfer in-flight registration routines
        https://git.kernel.org/sudeep.holla/c/9374324e8d78
[02/17] firmware: arm_scmi: Refactor polling helpers
        https://git.kernel.org/sudeep.holla/c/d5552a45c828
[03/17] firmware: arm_scmi: Refactor scmi_wait_for_message_response
        https://git.kernel.org/sudeep.holla/c/ac49e46c453a
[04/17] firmware: arm_scmi: Add flags field to xfer
        https://git.kernel.org/sudeep.holla/c/0eb24e5a0ead
[05/17] firmware: arm_scmi: Add xfer Raw helpers
        https://git.kernel.org/sudeep.holla/c/aaa9d521b01a
[06/17] firmware: arm_scmi: Move errors defs and code to common.h
        https://git.kernel.org/sudeep.holla/c/5e15c2197fc7
[07/17] firmware: arm_scmi: Add internal platform/channel IDs
        https://git.kernel.org/sudeep.holla/c/5b6034808c96
[08/17] include: trace: Add platform and channel instance references
        https://git.kernel.org/sudeep.holla/c/bd752cc79916
[09/17] debugfs: Export debugfs_create_str symbol
        https://git.kernel.org/sudeep.holla/c/cade53b60a04
[10/17] firmware: arm_scmi: Populate a common SCMI debugsfs root
        https://git.kernel.org/sudeep.holla/c/f5bc54a5041b
[11/17] firmware: arm_scmi: Add debugfs ABI documentation for common entries
        https://git.kernel.org/sudeep.holla/c/b5dc013d98b4
[12/17] firmware: arm_scmi: Add core Raw transmission support
        https://git.kernel.org/sudeep.holla/c/e789a8ab15b0
[13/17] firmware: arm_scmi: Add debugfs ABI documentation for Raw mode
        https://git.kernel.org/sudeep.holla/c/25376d813405
[14/17] firmware: arm_scmi: Reject SCMI drivers while in Raw mode
        https://git.kernel.org/sudeep.holla/c/9e834da670ce
[15/17] firmware: arm_scmi: Call Raw mode hooks from the core stack
        https://git.kernel.org/sudeep.holla/c/a6fb9dc05c8c
[16/17] firmware: arm_scmi: Add Raw mode coexistence support
        https://git.kernel.org/sudeep.holla/c/145f03626257
[17/17] firmware: arm_scmi: Add per-channel Raw injection support
        https://git.kernel.org/sudeep.holla/c/eeb087fa365a

--
Regards,
Sudeep

Re: [PATCH v8 00/17] Introduce a unified API for SCMI Server testing

[Florian Fainelli]

Hi Christian,

On 1/18/23 04:14, Cristian Marussi wrote:
> Hi all,
> 
> This series aims to introduce a new SCMI unified userspace interface meant
> to ease testing an SCMI Server implementation for compliance, fuzzing etc.,
> from the perspective of the OSPM agent (non-secure world only ...)
> 
> It is proposed as a testing/development facility, it is NOT meant to be a
> feature to use in production, but only enabled in Kconfig for test
> deployments.
> 
> Currently an SCMI Compliance Suite like the one at [1] can only work by
> injecting SCMI messages at the SCMI transport layer using the mailbox test
> driver (CONFIG_MAILBOX_TEST) via its few debugfs entries and looking at
> the related replies from the SCMI backend Server.

Took a while but finally:

Tested-by: Florian Fainelli <f.fainelli@gmail.com>

Any idea when the raw_mode_support or the acs_raw_mode_support will hit 
your master branch in the scmi-tests repository?
-- 
Florian

Re: [PATCH v8 00/17] Introduce a unified API for SCMI Server testing

[Vincent Guittot]

On Wed, 18 Jan 2023 at 13:15, Cristian Marussi <cristian.marussi@arm.com> wrote:
>
> Hi all,
>
> This series aims to introduce a new SCMI unified userspace interface meant
> to ease testing an SCMI Server implementation for compliance, fuzzing etc.,
> from the perspective of the OSPM agent (non-secure world only ...)
>
> It is proposed as a testing/development facility, it is NOT meant to be a
> feature to use in production, but only enabled in Kconfig for test
> deployments.
>
> Currently an SCMI Compliance Suite like the one at [1] can only work by
> injecting SCMI messages at the SCMI transport layer using the mailbox test
> driver (CONFIG_MAILBOX_TEST) via its few debugfs entries and looking at
> the related replies from the SCMI backend Server.
>
> This approach has a few drawbacks:
>
> - the SCMI Server under test MUST be reachable through a mailbox based
>   SCMI transport: any other SCMI Server placement is not possible (like in
>   a VM reachable via SCMI Virtio). In order to cover other placements in
>   the current scenario we should write some sort of test driver for each
>   and every existent SCMI transport and for any future additional transport
>   ...this clearly does not scale.
>
> - even in the mailbox case the userspace Compliance suite cannot simply
>   send and receive bare SCMI messages BUT it has to properly lay them out
>   into the shared memory exposed by the mailbox test driver as expected by
>   the transport definitions. In other words such a userspace test
>   application has to, not only use a proper transport driver for the system
>   at hand, but it also has to have a comprehensive knowledge of the
>   internals of the underlying transport in order to operate.
>
> - last but not least, the system under test has to be specifically
>   configured and built, in terms of Kconfig and DT, to perform such kind of
>   testing, it cannot be used for anything else, which is unfortunate for
>   CI/CD deployments.
>
> This series introduces a new SCMI Raw mode support feature that, when
> configured and enabled exposes a new interface in debugfs through which:
>
> - a userspace application can inject bare SCMI binary messages into the
>   SCMI core stack; such messages will be routed by the SCMI regular kernel
>   stack to the backend Server using the currently configured transport
>   transparently: in other words you can test the SCMI server, no matter
>   where it is placed, as long as it is reachable from the currently
>   configured SCMI stack.
>   Same goes the other way around on the reading path: any SCMI server reply
>   can be read as a bare SCMI binary message from the same debugfs path.
>
> - as a direct consequence of this way of injecting bare messages in the
>   middle of the SCMI stack (instead of beneath it at the transport layer)
>   the user application has to handle only bare SCMI messages without having
>   to worry about the specific underlying transport internals that will be
>   taken care of by the SCMI core stack itself using its own machinery,
>   without duplicating such logic.
>
> - a system under test, once configured with SCMI Raw support enabled in
>   Kconfig, can be booted without any particular DT change.
>
> Latest V6 additions:
>
>  - improved scmi traces for msg dumps to include used channels
>  - added a new common SCMI debugfs root fs
>  - reworked SCMI Raw debugfs layout
>  - added support of a new additional per-channel API that allows a user to
>    select a specific egress channel for the message injection (when more
>    than one channel is available)
>
> A quick and trivial example from the shell...reading from a sensor by
> injecting a properly crafted packet in raw mode (letting the stack select
> the channel):
>
>         # INJECT THE SENSOR_READING MESSAGE FOR SENSOR ID=1 (binary little endian)
>         root@deb-buster-arm64:~# echo -e -n \\x06\\x54\\x00\\x00\\x01\\x00\\x00\\x00\\x00\\x00\\x00\\x00 > /sys/kernel/debug/scmi/0/raw/message
>
>         # READING BACK THE REPLY...
>         root@deb-buster-arm64:~# cat /sys/kernel/debug/scmi/0/raw/message | od --endian=little -t x4
>         0000000 00005406 00000000 00000335 00000000
>         0000020
>
> while doing that, since Raw mode makes (partial) use of the regular SCMI
> stack, you can observe the messages going through the SCMI stack with the
> usual traces:
>
>               bash-329     [000] ..... 14183.446808: scmi_msg_dump: id=0 ch=10 pt=15 t=cmnd msg_id=06 seq=0000 s=0 pyld=0100000000000000
>    irq/35-mhu_db_l-81      [000] ..... 14183.447809: scmi_msg_dump: id=0 ch=10 pt=15 t=resp msg_id=06 seq=0000 s=0 pyld=3503000000000000
>
> ..trying to read in async when the backend server does NOT supports asyncs:
>
>         # AN ASYNC SENSOR READING REQUEST...
>         root@deb-buster-arm64:~# echo -e -n \\x06\\x54\\x00\\x00\\x01\\x00\\x00\\x00\\x01\\x00\\x00\\x00 > /sys/kernel/debug/scmi/0/raw/message_async
>
>               bash-329     [000] ..... 16415.938739: scmi_msg_dump: id=0 ch=10 pt=15 t=cmnd msg_id=06 seq=0000 s=0 pyld=0100000001000000
>    irq/35-mhu_db_l-81      [000] ..... 16415.944129: scmi_msg_dump: id=0 ch=10 pt=15 t=resp msg_id=06 seq=0000 s=-1 pyld=
>
>         # RETURNS A STATUS -1 FROM THE SERVER NOT SUPPORTING IT
>         root@deb-buster-arm64:~# cat /sys/kernel/debug/scmi/0/raw/message | od --endian=little -t x4
>         0000000 00005406 ffffffff
>         0000010
>
> Note that the above example was on a JUNO, BUT exactly the same steps can
> be used to reach an SCMI Server living on a VM reachable via virtio as
> long as the system under test if properly configured to work with a
> virtio transport.
>
> In a nutshell the exposed API is as follows:
>
> /sys/kernel/debug/scmi/
> `-- 0
>     |-- atomic_threshold_us
>     |-- instance_name
>     |-- raw
>     |   |-- channels
>     |   |   |-- 0x10
>     |   |   |   |-- message
>     |   |   |   `-- message_async
>     |   |   `-- 0x13
>     |   |       |-- message
>     |   |       `-- message_async
>     |   |-- errors
>     |   |-- message
>     |   |-- message_async
>     |   |-- notification
>     |   `-- reset
>     `-- transport
>         |-- is_atomic
>         |-- max_msg_size
>         |-- max_rx_timeout_ms
>         |-- rx_max_msg
>         |-- tx_max_msg
>         `-- type
>
> ... where at the top level:
>
>  - <N>: a progressive sequence number identifying this SCMI instance, in
>    case there are multiple SCMI instance defined
>
>  - instance_name: can be used (by CI) to identify the SCMI instance <N>
>    that you are using through this Raw accessors: it corresponds to the SCMI
>    DT top node full name of the underlying SCMI instance
>
>
> ... rooted under /transport:
>
>  - a bunch of configuration info useful to setup the user application
>    expectations in terms of timeouts and message characteristics.
>
>
> ... rooted at /raw (the real SCMI Raw interface :D):
>
>  - message*: used to send sync/async commands and read back immediate and
>    delayed responses (if any)
>  - errors: used to report timeout and unexpected replies
>  - reset: used to reset the SCMI Raw stack, flushing all queues from
>    received messages still pending to be read out (useful to be sure to
>    cleanup between test suite runs...)
>  - notification: used to read any notification being spit by the system
>    (if previously enabled by the user app)
>
>
> ... rooted at /raw/channels/<M>/:

I haven't seen a description of the <M>. I figured out that this is
the protocol id to which the channel was associated in DT while
testing it but it could be good to describe this somewhere.
Apart from this minor thing, I have tested it with an scmi server
embedded in OPTEE and run the scmi compliance tests. Everything works
fine using the default mode or using one specific channel.

FWIW
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>

Thanks

>
>  - message*: used to send sync/async commands and read back immediate and
>    delayed responses (if any), using a SPECIFIC transport channel <M>
>    (instead of letting the system choose for you based on transport config
>     and the rotocol embedded in the injected message)
>    NOTE THAT these entries are optional, created only if there is more than
>    transport channel defined on the system.
>
> Each write corresponds to one command request and the replies or delayed
> response are read back one message at time (receiving an EOF at each
> message boundary).
>
> The user application running the test is in charge of handling timeouts
> and properly choosing SCMI sequence numbers for the outgoing requests: note
> that the same fixed number can be re-used (...though discouraged...) as
> long as the suite does NOT expect to send multiple in-flight commands
> concurrently.
>
> Since the SCMI core regular stack is partially used to deliver and collect
> the messages, late replies after timeouts and any other sort of unexpected
> message sent by the SCMI server platform back can be identified by the SCMI
> core as usual and it will be reported under /errors for later analysis.
> (a userspace test-app will have anyway properly detected the timeout on
>  /message* ...)
>
> All of the above has been roughly tested against a standard JUNO SCP SCMI
> Server (mailbox trans) and an emulated SCMI Server living in a VM (virtio
> trans) using a custom experimental version of the scmi-tests Compliance
> suite patched to support Raw mode and posted at [2]. (still in development
> ...merge requests are in progress...for now it is just a mean for me to
> test the testing API ... O_o)
>
> This V8 series is based on v6.2-rc1 PLUS another series which reworked a
> bit the SCMI core stack init/probe [3]; to ease testing a V8 properly
> based can be picked up from [4].
>
> Having said that (in such a concise and brief way :P) ...
>
> ...any feedback/comments are welcome !
>
> Thanks,
> Cristian
>
> ---
> v7 --> v8
> - fixed a few bad handling on error path
> - ignoring debugfs_ retvals as supposed to
> - using XArray for per-channel queus instead of IDRs
> - refactored debugfs setup calls
>
> v6 --> v7
> - fixed one sparse error
> - removed redundant info.num_chans/channels fields: enumerate them dyamically
>   once needed.
>
> v5 --> v6
> - exported symbol debugfs_create_str
> - rebased on top of v6.2-rc1 plus series at [3]
> - redesigned SCMI debugfs layout with a bunch of common entries
>   enabled by implicit CONFIG_ARM_SCMI_NEED_DEBUGFS
> - refactored SCMI Raw internal queues handling
> - added SCMI Raw per-channel injection support
> - added channels info on SCMI msg_dump traces
> - fix debugfs multiple writers cases
> - added DEBUG_FS dependency to Raw mode
> - select CONFIG_ARM_SCMI_NEED_DEBUGFS when Raw mode is compiled
>
> v4 --> v5
> - rebased on sudeep/for-next/scmi
> - added multiple SCMI instances support
> - added optional Raw full-cohexistence mode
> - use custom tags to distinguish Raw msg_dump traces
> - add circular handling of raw buffers queues for errors and notifications
>
> V3 --> v4
> - rebased on v6.1-rc1
> - addedd missing support for 'polled' transports and transport lacking a
>   completion_irq (like smc/optee)
> - removed a few inlines
> - refactored SCMI Raw RX patch to make use more extensively of the regular
>   non-Raw RX path
> - fix handling of O_NONBLOCK raw_mode read requests
>
> v2 --> v3
> - fixed some sparse warning on LE and __poll_t
> - reworked and simplified deferred worker in charge of xfer delayed waiting
> - allow for injection of DT-unknown protocols messages when in Raw mode
>   (needed for any kind of fuzzing...)
>
> v1 --> v2
> - added comments and debugfs docs
> - added dedicated transport devices for channels initialization
> - better channels handling in Raw mode
> - removed runtime enable, moved to static compile time exclusion
>   of SCMI regular stack
>
> [1]: https://gitlab.arm.com/tests/scmi-tests
> [2]: https://gitlab.arm.com/tests/scmi-tests/-/commits/raw_mode_support_devel/
> [3]: https://lore.kernel.org/all/20221222185049.737625-1-cristian.marussi@arm.com/
> [4]: https://gitlab.arm.com/linux-arm/linux-cm/-/commits/scmi_raw_mode_V8/
>
>
> Cristian Marussi (17):
>   firmware: arm_scmi: Refactor xfer in-flight registration routines
>   firmware: arm_scmi: Refactor polling helpers
>   firmware: arm_scmi: Refactor scmi_wait_for_message_response
>   firmware: arm_scmi: Add flags field to xfer
>   firmware: arm_scmi: Add xfer Raw helpers
>   firmware: arm_scmi: Move errors defs and code to common.h
>   firmware: arm_scmi: Add internal platform/channel IDs
>   include: trace: Add platform and channel instance references
>   debugfs: Export debugfs_create_str symbol
>   firmware: arm_scmi: Populate a common SCMI debugsfs root
>   firmware: arm_scmi: Add debugfs ABI documentation for common entries
>   firmware: arm_scmi: Add core Raw transmission support
>   firmware: arm_scmi: Add debugfs ABI documentation for Raw mode
>   firmware: arm_scmi: Reject SCMI drivers while in Raw mode
>   firmware: arm_scmi: Call Raw mode hooks from the core stack
>   firmware: arm_scmi: Add Raw mode coexistence support
>   firmware: arm_scmi: Add per-channel Raw injection support
>
>  Documentation/ABI/testing/debugfs-scmi     |   70 +
>  Documentation/ABI/testing/debugfs-scmi-raw |  109 ++
>  drivers/firmware/arm_scmi/Kconfig          |   32 +
>  drivers/firmware/arm_scmi/Makefile         |    1 +
>  drivers/firmware/arm_scmi/bus.c            |    7 +
>  drivers/firmware/arm_scmi/common.h         |   75 +
>  drivers/firmware/arm_scmi/driver.c         |  638 +++++++--
>  drivers/firmware/arm_scmi/protocols.h      |    7 +
>  drivers/firmware/arm_scmi/raw_mode.c       | 1443 ++++++++++++++++++++
>  drivers/firmware/arm_scmi/raw_mode.h       |   31 +
>  fs/debugfs/file.c                          |    1 +
>  include/trace/events/scmi.h                |   18 +-
>  12 files changed, 2292 insertions(+), 140 deletions(-)
>  create mode 100644 Documentation/ABI/testing/debugfs-scmi
>  create mode 100644 Documentation/ABI/testing/debugfs-scmi-raw
>  create mode 100644 drivers/firmware/arm_scmi/raw_mode.c
>  create mode 100644 drivers/firmware/arm_scmi/raw_mode.h
>
> --
> 2.34.1
>

Re: [PATCH v8 00/17] Introduce a unified API for SCMI Server testing

[Cristian Marussi]

On Thu, Jan 19, 2023 at 01:47:04PM -0800, Florian Fainelli wrote:
> Hi Christian,
> 
Hi Florian,

> On 1/18/23 04:14, Cristian Marussi wrote:
> > Hi all,
> > 
> > This series aims to introduce a new SCMI unified userspace interface meant
> > to ease testing an SCMI Server implementation for compliance, fuzzing etc.,
> > from the perspective of the OSPM agent (non-secure world only ...)
> > 
> > It is proposed as a testing/development facility, it is NOT meant to be a
> > feature to use in production, but only enabled in Kconfig for test
> > deployments.
> > 
> > Currently an SCMI Compliance Suite like the one at [1] can only work by
> > injecting SCMI messages at the SCMI transport layer using the mailbox test
> > driver (CONFIG_MAILBOX_TEST) via its few debugfs entries and looking at
> > the related replies from the SCMI backend Server.
> 
> Took a while but finally:
> 
> Tested-by: Florian Fainelli <f.fainelli@gmail.com>
> 

Thanks for giving it a go.

> Any idea when the raw_mode_support or the acs_raw_mode_support will hit your
> master branch in the scmi-tests repository?

I was holding off waiting for this series to be merged to be sure the
debugfs ABI was not changing anymore, so now, soon-ish, I'll move to request
merge the Raw support in the ACS too; the only further delay regarding this,
that I can think of, could be that I know QA is also adding v3.1 tests to the
ACS and they are too going for the MR in these days, so this could delay a bit
further the Raw support merge.

Thanks,
Cristian

Re: [PATCH v8 00/17] Introduce a unified API for SCMI Server testing

[Cristian Marussi]

On Fri, Jan 20, 2023 at 09:11:24AM +0100, Vincent Guittot wrote:
> On Wed, 18 Jan 2023 at 13:15, Cristian Marussi <cristian.marussi@arm.com> wrote:
> >
> > Hi all,
> >
> > This series aims to introduce a new SCMI unified userspace interface meant
> > to ease testing an SCMI Server implementation for compliance, fuzzing etc.,
> > from the perspective of the OSPM agent (non-secure world only ...)
> >
> > It is proposed as a testing/development facility, it is NOT meant to be a
> > feature to use in production, but only enabled in Kconfig for test
> > deployments.
> >
> > Currently an SCMI Compliance Suite like the one at [1] can only work by
> > injecting SCMI messages at the SCMI transport layer using the mailbox test
> > driver (CONFIG_MAILBOX_TEST) via its few debugfs entries and looking at
> > the related replies from the SCMI backend Server.
> >
> > This approach has a few drawbacks:
> >
> > - the SCMI Server under test MUST be reachable through a mailbox based
> >   SCMI transport: any other SCMI Server placement is not possible (like in
> >   a VM reachable via SCMI Virtio). In order to cover other placements in
> >   the current scenario we should write some sort of test driver for each
> >   and every existent SCMI transport and for any future additional transport
> >   ...this clearly does not scale.
> >
> > - even in the mailbox case the userspace Compliance suite cannot simply
> >   send and receive bare SCMI messages BUT it has to properly lay them out
> >   into the shared memory exposed by the mailbox test driver as expected by
> >   the transport definitions. In other words such a userspace test
> >   application has to, not only use a proper transport driver for the system
> >   at hand, but it also has to have a comprehensive knowledge of the
> >   internals of the underlying transport in order to operate.
> >
> > - last but not least, the system under test has to be specifically
> >   configured and built, in terms of Kconfig and DT, to perform such kind of
> >   testing, it cannot be used for anything else, which is unfortunate for
> >   CI/CD deployments.
> >
> > This series introduces a new SCMI Raw mode support feature that, when
> > configured and enabled exposes a new interface in debugfs through which:
> >
> > - a userspace application can inject bare SCMI binary messages into the
> >   SCMI core stack; such messages will be routed by the SCMI regular kernel
> >   stack to the backend Server using the currently configured transport
> >   transparently: in other words you can test the SCMI server, no matter
> >   where it is placed, as long as it is reachable from the currently
> >   configured SCMI stack.
> >   Same goes the other way around on the reading path: any SCMI server reply
> >   can be read as a bare SCMI binary message from the same debugfs path.
> >
> > - as a direct consequence of this way of injecting bare messages in the
> >   middle of the SCMI stack (instead of beneath it at the transport layer)
> >   the user application has to handle only bare SCMI messages without having
> >   to worry about the specific underlying transport internals that will be
> >   taken care of by the SCMI core stack itself using its own machinery,
> >   without duplicating such logic.
> >
> > - a system under test, once configured with SCMI Raw support enabled in
> >   Kconfig, can be booted without any particular DT change.
> >
> > Latest V6 additions:
> >
> >  - improved scmi traces for msg dumps to include used channels
> >  - added a new common SCMI debugfs root fs
> >  - reworked SCMI Raw debugfs layout
> >  - added support of a new additional per-channel API that allows a user to
> >    select a specific egress channel for the message injection (when more
> >    than one channel is available)
> >
> > A quick and trivial example from the shell...reading from a sensor by
> > injecting a properly crafted packet in raw mode (letting the stack select
> > the channel):
> >
> >         # INJECT THE SENSOR_READING MESSAGE FOR SENSOR ID=1 (binary little endian)
> >         root@deb-buster-arm64:~# echo -e -n \\x06\\x54\\x00\\x00\\x01\\x00\\x00\\x00\\x00\\x00\\x00\\x00 > /sys/kernel/debug/scmi/0/raw/message
> >
> >         # READING BACK THE REPLY...
> >         root@deb-buster-arm64:~# cat /sys/kernel/debug/scmi/0/raw/message | od --endian=little -t x4
> >         0000000 00005406 00000000 00000335 00000000
> >         0000020
> >
> > while doing that, since Raw mode makes (partial) use of the regular SCMI
> > stack, you can observe the messages going through the SCMI stack with the
> > usual traces:
> >
> >               bash-329     [000] ..... 14183.446808: scmi_msg_dump: id=0 ch=10 pt=15 t=cmnd msg_id=06 seq=0000 s=0 pyld=0100000000000000
> >    irq/35-mhu_db_l-81      [000] ..... 14183.447809: scmi_msg_dump: id=0 ch=10 pt=15 t=resp msg_id=06 seq=0000 s=0 pyld=3503000000000000
> >
> > ..trying to read in async when the backend server does NOT supports asyncs:
> >
> >         # AN ASYNC SENSOR READING REQUEST...
> >         root@deb-buster-arm64:~# echo -e -n \\x06\\x54\\x00\\x00\\x01\\x00\\x00\\x00\\x01\\x00\\x00\\x00 > /sys/kernel/debug/scmi/0/raw/message_async
> >
> >               bash-329     [000] ..... 16415.938739: scmi_msg_dump: id=0 ch=10 pt=15 t=cmnd msg_id=06 seq=0000 s=0 pyld=0100000001000000
> >    irq/35-mhu_db_l-81      [000] ..... 16415.944129: scmi_msg_dump: id=0 ch=10 pt=15 t=resp msg_id=06 seq=0000 s=-1 pyld=
> >
> >         # RETURNS A STATUS -1 FROM THE SERVER NOT SUPPORTING IT
> >         root@deb-buster-arm64:~# cat /sys/kernel/debug/scmi/0/raw/message | od --endian=little -t x4
> >         0000000 00005406 ffffffff
> >         0000010
> >
> > Note that the above example was on a JUNO, BUT exactly the same steps can
> > be used to reach an SCMI Server living on a VM reachable via virtio as
> > long as the system under test if properly configured to work with a
> > virtio transport.
> >
> > In a nutshell the exposed API is as follows:
> >
> > /sys/kernel/debug/scmi/
> > `-- 0
> >     |-- atomic_threshold_us
> >     |-- instance_name
> >     |-- raw
> >     |   |-- channels
> >     |   |   |-- 0x10
> >     |   |   |   |-- message
> >     |   |   |   `-- message_async
> >     |   |   `-- 0x13
> >     |   |       |-- message
> >     |   |       `-- message_async
> >     |   |-- errors
> >     |   |-- message
> >     |   |-- message_async
> >     |   |-- notification
> >     |   `-- reset
> >     `-- transport
> >         |-- is_atomic
> >         |-- max_msg_size
> >         |-- max_rx_timeout_ms
> >         |-- rx_max_msg
> >         |-- tx_max_msg
> >         `-- type
> >
> > ... where at the top level:
> >
> >  - <N>: a progressive sequence number identifying this SCMI instance, in
> >    case there are multiple SCMI instance defined
> >
> >  - instance_name: can be used (by CI) to identify the SCMI instance <N>
> >    that you are using through this Raw accessors: it corresponds to the SCMI
> >    DT top node full name of the underlying SCMI instance
> >
> >
> > ... rooted under /transport:
> >
> >  - a bunch of configuration info useful to setup the user application
> >    expectations in terms of timeouts and message characteristics.
> >
> >
> > ... rooted at /raw (the real SCMI Raw interface :D):
> >
> >  - message*: used to send sync/async commands and read back immediate and
> >    delayed responses (if any)
> >  - errors: used to report timeout and unexpected replies
> >  - reset: used to reset the SCMI Raw stack, flushing all queues from
> >    received messages still pending to be read out (useful to be sure to
> >    cleanup between test suite runs...)
> >  - notification: used to read any notification being spit by the system
> >    (if previously enabled by the user app)
> >
> >
> > ... rooted at /raw/channels/<M>/:
> 

Hi Vincent,

thanks for trying this out.

> I haven't seen a description of the <M>. I figured out that this is
> the protocol id to which the channel was associated in DT while
> testing it but it could be good to describe this somewhere.

Ah, damn yes, I had made a note to myself to add an explicit description
of how the channel number IDs are chosen, then I forgot :P

I'll add a follow-on patch once is queued.

> Apart from this minor thing, I have tested it with an scmi server
> embedded in OPTEE and run the scmi compliance tests. Everything works
> fine using the default mode or using one specific channel.
> 
> FWIW
> Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
> 

Thanks,
Cristian

Re: [PATCH v8 00/17] Introduce a unified API for SCMI Server testing

[Sudeep Holla]

On Fri, Jan 20, 2023 at 09:56:32AM +0000, Cristian Marussi wrote:
> On Fri, Jan 20, 2023 at 09:11:24AM +0100, Vincent Guittot wrote:
> 
> Hi Vincent,
> 
> thanks for trying this out.
> 
> > I haven't seen a description of the <M>. I figured out that this is
> > the protocol id to which the channel was associated in DT while
> > testing it but it could be good to describe this somewhere.
> 
> Ah, damn yes, I had made a note to myself to add an explicit description
> of how the channel number IDs are chosen, then I forgot :P
> 
> I'll add a follow-on patch once is queued.
>

Please post it ASAP so that I can include it before I tag, just trying
to avoid missing it now and sending it as fix later :).

> > Apart from this minor thing, I have tested it with an scmi server
> > embedded in OPTEE and run the scmi compliance tests. Everything works
> > fine using the default mode or using one specific channel.
> > 
> > FWIW
> > Tested-by: Vincent Guittot <vincent.guittot@linaro.org>

Thanks Vincent and Florian. I just pulled and merged this last night, will
update to include your Tested-by tags.

--
Regards,
Sudeep

Re: [PATCH v8 00/17] Introduce a unified API for SCMI Server testing

[Sudeep Holla]

On Wed, 18 Jan 2023 12:14:09 +0000, Cristian Marussi wrote:
> This series aims to introduce a new SCMI unified userspace interface meant
> to ease testing an SCMI Server implementation for compliance, fuzzing etc.,
> from the perspective of the OSPM agent (non-secure world only ...)
> 
> It is proposed as a testing/development facility, it is NOT meant to be a
> feature to use in production, but only enabled in Kconfig for test
> deployments.
> 
> [...]

Re-applied to sudeep.holla/linux (for-next/scmi) with Tested-by tags now, thanks!

[01/17] firmware: arm_scmi: Refactor xfer in-flight registration routines
        https://git.kernel.org/sudeep.holla/c/b0e924a955cb
[02/17] firmware: arm_scmi: Refactor polling helpers
        https://git.kernel.org/sudeep.holla/c/f21c2b0ba8f3
[03/17] firmware: arm_scmi: Refactor scmi_wait_for_message_response
        https://git.kernel.org/sudeep.holla/c/07cdfc44f1a4
[04/17] firmware: arm_scmi: Add flags field to xfer
        https://git.kernel.org/sudeep.holla/c/37057bf2b509
[05/17] firmware: arm_scmi: Add xfer Raw helpers
        https://git.kernel.org/sudeep.holla/c/3095a3e25d8f
[06/17] firmware: arm_scmi: Move errors defs and code to common.h
        https://git.kernel.org/sudeep.holla/c/936a2b91c2e8
[07/17] firmware: arm_scmi: Add internal platform/channel IDs
        https://git.kernel.org/sudeep.holla/c/75c86dc72dc8
[08/17] include: trace: Add platform and channel instance references
        https://git.kernel.org/sudeep.holla/c/8b2bd71119dd
[09/17] debugfs: Export debugfs_create_str symbol
        https://git.kernel.org/sudeep.holla/c/d60b59b96795
[10/17] firmware: arm_scmi: Populate a common SCMI debugsfs root
        https://git.kernel.org/sudeep.holla/c/c3d4aed763ce
[11/17] firmware: arm_scmi: Add debugfs ABI documentation for common entries
        https://git.kernel.org/sudeep.holla/c/0f62ed0092ec
[12/17] firmware: arm_scmi: Add core Raw transmission support
        https://git.kernel.org/sudeep.holla/c/3c3d818a9317
[13/17] firmware: arm_scmi: Add debugfs ABI documentation for Raw mode
        https://git.kernel.org/sudeep.holla/c/74225707b334
[14/17] firmware: arm_scmi: Reject SCMI drivers while in Raw mode
        https://git.kernel.org/sudeep.holla/c/ba80acb0dfca
[15/17] firmware: arm_scmi: Call Raw mode hooks from the core stack
        https://git.kernel.org/sudeep.holla/c/7063887b5386
[16/17] firmware: arm_scmi: Add Raw mode coexistence support
        https://git.kernel.org/sudeep.holla/c/9c54633e4e3d
[17/17] firmware: arm_scmi: Add per-channel Raw injection support
        https://git.kernel.org/sudeep.holla/c/7860701d1e6e

--
Regards,
Sudeep