firmware: arm_scmi: Add per-channel raw injection support

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>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20230118121426.492864-18-cristian.marussi@arm.comSigned-off-by: Sudeep Holla <sudeep.holla@arm.com>

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

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 {

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);

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;

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);