[PATCH v3 0/2] firmware: arm_scmi/imx: Support dump syslog

[PATCH v3 0/2] firmware: arm_scmi/imx: Support dump syslog

[Peng Fan]

This is the patch 5 and 6 from patchset [1] with switching to using raw
dump, per check with Sudeep and NXP i.MX SM firmware owner

System Manager firmware provides API to dump system log information.
So add the interface for Linux to retrieve the information.

In patch 1, I drop the two structures compared to patch 5 in [1]:
struct scmi_imx_misc_sys_sleep_rec
struct scmi_imx_misc_syslog
No other changes in this patch.

In patch 2, I switched to use debugfs to do raw dump the syslog, compared
with patch 6 in [1].

[1] https://lore.kernel.org/arm-scmi/PAXPR04MB845937237E3C1AF5A2ABA8FA880CA@PAXPR04MB8459.eurprd04.prod.outlook.com/T/#m6ed303ac9c584c6e2ab39f89359f3131b
dfcc9e5

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
Changes in v3:
- Rebased to next-20251028
- Drop unused variable to avoid build warning reported by kernel test robot
- Link to v2: https://lore.kernel.org/arm-scmi/20251011-sm-syslog-v2-1-v2-0-f43a3f6b32e4@nxp.com/

Changes in v2:
- Rebased to next-20251010
- Patch 2: Remove the IS_ERR check for debugfs_create_dir per Dan Carpenter
           Change 'return 0' to 'return devm_add_action_or_reset'
	   Drop the size check
	   Include 'linux/sizes.h' to avoid build break
- Link to v1: https://lore.kernel.org/r/20250910-sm-syslog-v1-0-5b36f8f21da6@nxp.com

---
Peng Fan (2):
      firmware: arm_scmi: imx: Support getting syslog of MISC protocol
      firmware: imx: sm-misc: Dump syslog info

 .../firmware/arm_scmi/vendors/imx/imx-sm-misc.c    | 83 ++++++++++++++++++++++
 drivers/firmware/imx/sm-misc.c                     | 37 +++++++++-
 include/linux/scmi_imx_protocol.h                  |  2 +
 3 files changed, 121 insertions(+), 1 deletion(-)
---
base-commit: f7d2388eeec24966fc4d5cf32d706f0514f29ac5
change-id: 20251029-sm-syslog-v3-0143f85b0ce6

Best regards,
-- 
Peng Fan <peng.fan@nxp.com>

[PATCH v3 1/2] firmware: arm_scmi: imx: Support getting syslog of MISC protocol

[Peng Fan]

MISC protocol supports getting system log regarding system sleep latency,
wakeup interrupt and etc. Add the API for user to retrieve the information
from SM.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 .../firmware/arm_scmi/vendors/imx/imx-sm-misc.c    | 83 ++++++++++++++++++++++
 include/linux/scmi_imx_protocol.h                  |  2 +
 2 files changed, 85 insertions(+)

diff --git a/drivers/firmware/arm_scmi/vendors/imx/imx-sm-misc.c b/drivers/firmware/arm_scmi/vendors/imx/imx-sm-misc.c
index 700a3f24f4efc153ca4a9ef1a9e50a7ece492a18..eae0b0562f6cf1931be612852ba2651f60820e6d 100644
--- a/drivers/firmware/arm_scmi/vendors/imx/imx-sm-misc.c
+++ b/drivers/firmware/arm_scmi/vendors/imx/imx-sm-misc.c
@@ -28,6 +28,7 @@ enum scmi_imx_misc_protocol_cmd {
 	SCMI_IMX_MISC_DISCOVER_BUILD_INFO = 0x6,
 	SCMI_IMX_MISC_CTRL_NOTIFY = 0x8,
 	SCMI_IMX_MISC_CFG_INFO_GET = 0xC,
+	SCMI_IMX_MISC_SYSLOG_GET = 0xD,
 	SCMI_IMX_MISC_BOARD_INFO = 0xE,
 };
 
@@ -89,6 +90,19 @@ struct scmi_imx_misc_cfg_info_out {
 	u8 cfgname[MISC_MAX_CFGNAME];
 };
 
+struct scmi_imx_misc_syslog_in {
+	__le32 flags;
+	__le32 index;
+};
+
+#define REMAINING(x)	le32_get_bits((x), GENMASK(31, 20))
+#define RETURNED(x)	le32_get_bits((x), GENMASK(11, 0))
+
+struct scmi_imx_misc_syslog_out {
+	__le32 numlogflags;
+	__le32 syslog[];
+};
+
 static int scmi_imx_misc_attributes_get(const struct scmi_protocol_handle *ph,
 					struct scmi_imx_misc_info *mi)
 {
@@ -371,10 +385,79 @@ static int scmi_imx_misc_cfg_info_get(const struct scmi_protocol_handle *ph)
 	return ret;
 }
 
+struct scmi_imx_misc_syslog_ipriv {
+	u32 *array;
+	u16 *size;
+};
+
+static void iter_misc_syslog_prepare_message(void *message, u32 desc_index,
+					     const void *priv)
+{
+	struct scmi_imx_misc_syslog_in *msg = message;
+
+	msg->flags = cpu_to_le32(0);
+	msg->index = cpu_to_le32(desc_index);
+}
+
+static int iter_misc_syslog_update_state(struct scmi_iterator_state *st,
+					 const void *response, void *priv)
+{
+	const struct scmi_imx_misc_syslog_out *r = response;
+	struct scmi_imx_misc_syslog_ipriv *p = priv;
+
+	st->num_returned = RETURNED(r->numlogflags);
+	st->num_remaining = REMAINING(r->numlogflags);
+	*p->size = st->num_returned + st->num_remaining;
+
+	return 0;
+}
+
+static int
+iter_misc_syslog_process_response(const struct scmi_protocol_handle *ph,
+				  const void *response,
+				  struct scmi_iterator_state *st, void *priv)
+{
+	const struct scmi_imx_misc_syslog_out *r = response;
+	struct scmi_imx_misc_syslog_ipriv *p = priv;
+
+	p->array[st->desc_index + st->loop_idx] =
+		le32_to_cpu(r->syslog[st->loop_idx]);
+
+	return 0;
+}
+
+static int scmi_imx_misc_syslog_get(const struct scmi_protocol_handle *ph, u16 *size,
+				    void *array)
+{
+	struct scmi_iterator_ops ops = {
+		.prepare_message = iter_misc_syslog_prepare_message,
+		.update_state = iter_misc_syslog_update_state,
+		.process_response = iter_misc_syslog_process_response,
+	};
+	struct scmi_imx_misc_syslog_ipriv ipriv = {
+		.array = array,
+		.size = size,
+	};
+	void *iter;
+
+	if (!array || !size || !*size)
+		return -EINVAL;
+
+	iter = ph->hops->iter_response_init(ph, &ops, *size, SCMI_IMX_MISC_SYSLOG_GET,
+					    sizeof(struct scmi_imx_misc_syslog_in),
+					    &ipriv);
+	if (IS_ERR(iter))
+		return PTR_ERR(iter);
+
+	/* If firmware return NOT SUPPORTED, propagate value to caller */
+	return ph->hops->iter_response_run(iter);
+}
+
 static const struct scmi_imx_misc_proto_ops scmi_imx_misc_proto_ops = {
 	.misc_ctrl_set = scmi_imx_misc_ctrl_set,
 	.misc_ctrl_get = scmi_imx_misc_ctrl_get,
 	.misc_ctrl_req_notify = scmi_imx_misc_ctrl_notify,
+	.misc_syslog = scmi_imx_misc_syslog_get,
 };
 
 static int scmi_imx_misc_protocol_init(const struct scmi_protocol_handle *ph)
diff --git a/include/linux/scmi_imx_protocol.h b/include/linux/scmi_imx_protocol.h
index 27bd372cbfb142b6acb0b1cf4b82f061529d0d45..2407d7693b6ba1303e07629e45e2a7eaaa906fd3 100644
--- a/include/linux/scmi_imx_protocol.h
+++ b/include/linux/scmi_imx_protocol.h
@@ -59,6 +59,8 @@ struct scmi_imx_misc_proto_ops {
 			     u32 *num, u32 *val);
 	int (*misc_ctrl_req_notify)(const struct scmi_protocol_handle *ph,
 				    u32 ctrl_id, u32 evt_id, u32 flags);
+	int (*misc_syslog)(const struct scmi_protocol_handle *ph, u16 *size,
+			   void *array);
 };
 
 /* See LMM_ATTRIBUTES in imx95.rst */

-- 
2.37.1

[PATCH v3 2/2] firmware: imx: sm-misc: Dump syslog info

[Peng Fan]

Add debugfs interface to read System Manager syslog info

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/imx/sm-misc.c | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/imx/sm-misc.c b/drivers/firmware/imx/sm-misc.c
index fc3ee12c2be878e0285183e3381c9514a63d5142..0a8ada329c9de3c1627da241bf142fa91a8085d7 100644
--- a/drivers/firmware/imx/sm-misc.c
+++ b/drivers/firmware/imx/sm-misc.c
@@ -3,12 +3,16 @@
  * Copyright 2024 NXP
  */
 
+#include <linux/debugfs.h>
+#include <linux/device/devres.h>
 #include <linux/firmware/imx/sm.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/scmi_protocol.h>
 #include <linux/scmi_imx_protocol.h>
+#include <linux/seq_file.h>
+#include <linux/sizes.h>
 
 static const struct scmi_imx_misc_proto_ops *imx_misc_ctrl_ops;
 static struct scmi_protocol_handle *ph;
@@ -44,10 +48,38 @@ static int scmi_imx_misc_ctrl_notifier(struct notifier_block *nb,
 	return 0;
 }
 
+static int syslog_show(struct seq_file *file, void *priv)
+{
+	/* 4KB is large enough for syslog */
+	void *syslog __free(kfree) = kmalloc(SZ_4K, GFP_KERNEL);
+	/* syslog API use num words, not num bytes */
+	u16 size = SZ_4K / 4;
+	int ret;
+
+	if (!ph)
+		return -ENODEV;
+
+	ret = imx_misc_ctrl_ops->misc_syslog(ph, &size, syslog);
+	if (ret)
+		return ret;
+
+	seq_hex_dump(file, " ", DUMP_PREFIX_NONE, 16, sizeof(u32), syslog, size * 4, false);
+	seq_putc(file, '\n');
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(syslog);
+
+static void scmi_imx_misc_put(void *p)
+{
+	debugfs_remove((struct dentry *)p);
+}
+
 static int scmi_imx_misc_ctrl_probe(struct scmi_device *sdev)
 {
 	const struct scmi_handle *handle = sdev->handle;
 	struct device_node *np = sdev->dev.of_node;
+	struct dentry *scmi_imx_dentry;
 	u32 src_id, flags;
 	int ret, i, num;
 
@@ -98,7 +130,10 @@ static int scmi_imx_misc_ctrl_probe(struct scmi_device *sdev)
 		}
 	}
 
-	return 0;
+	scmi_imx_dentry = debugfs_create_dir("scmi_imx", NULL);
+	debugfs_create_file("syslog", 0444, scmi_imx_dentry, &sdev->dev, &syslog_fops);
+
+	return devm_add_action_or_reset(&sdev->dev, scmi_imx_misc_put, scmi_imx_dentry);
 }
 
 static const struct scmi_device_id scmi_id_table[] = {

-- 
2.37.1