Re: [PATCH 5/7] firmware: arm_scmi: imx: Support getting syslog of MISC protocol

Hi Cristian,

On Fri, Jun 27, 2025 at 02:44:00PM +0100, Cristian Marussi wrote:

On Fri, Jun 27, 2025 at 02:03:48PM +0800, Peng Fan wrote:

quoted

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    | 78 ++++++++++++++++++++++
 include/linux/scmi_imx_protocol.h                  | 19 ++++++
 2 files changed, 97 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 d5b24bc4d4ca6c19f4cddfaea6e9d9b32a4c92f7..1a6d75357b76ce6bb7d06461999b368c27f1fa43 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_BUILDINFO = 0x6,
 	SCMI_IMX_MISC_SI_INFO = 0xB,
 	SCMI_IMX_MISC_CFG_INFO = 0xC,
+	SCMI_IMX_MISC_SYSLOG = 0xD,
 	SCMI_IMX_MISC_CTRL_NOTIFY = 0x8,
 };
 

@@ -87,6 +88,19 @@ struct scmi_imx_misc_si_info_out {
 	u8 siname[MISC_MAX_SINAME];
 };
 
+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)
 {

@@ -368,6 +382,69 @@ static int scmi_imx_misc_silicon_info(const struct scmi_protocol_handle *ph,
 	return ret;
 }
 
+struct scmi_imx_misc_syslog_ipriv {
+	u32 *array;
+};
+
+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;
+
+	st->num_returned = RETURNED(r->numlogflags);
+	st->num_remaining = REMAINING(r->numlogflags);
+
+	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(const struct scmi_protocol_handle *ph, u16 size,
+				void *array)
+{

...so this size...

quoted

+	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,
+	};
+	void *iter;
+
+	if (!array || !size)
+		return -EINVAL;
+

...which cannot be zero and is passed down to the iterator as max_resources
is meant to repreent also the length of tthe array passed here as an
argument and filled-in by the iterators ?

...and so basically array bounds-checking is enforced by the iterators
core code, because no matter what, it is always enforced that

(returned + remaining <= max_resources (size)

Right. I think set size to 0 does not make sense, so add a '(!size)' check

...I am fine with this, I am just trying to understand and see if I can
find a mishap :D

quoted

+	iter = ph->hops->iter_response_init(ph, &ops, size, SCMI_IMX_MISC_SYSLOG,
+					    sizeof(struct scmi_imx_misc_syslog_in),
+					    &ipriv);
+	if (IS_ERR(iter))
+		return PTR_ERR(iter);
+
+	return ph->hops->iter_response_run(iter);
+}
+
 static const struct scmi_imx_misc_proto_ops scmi_imx_misc_proto_ops = {
 	.misc_cfg_info = scmi_imx_misc_cfg_info,
 	.misc_ctrl_set = scmi_imx_misc_ctrl_set,

@@ -375,6 +452,7 @@ static const struct scmi_imx_misc_proto_ops scmi_imx_misc_proto_ops = {
 	.misc_ctrl_req_notify = scmi_imx_misc_ctrl_notify,
 	.misc_discover_build_info = scmi_imx_discover_build_info,
 	.misc_silicon_info = scmi_imx_misc_silicon_info,
+	.misc_syslog = scmi_imx_misc_syslog,
 };
 
 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 0e639dfb5d16e281e2ccf006a63694b316c431f4..ff34d974046aa982fa9f5d46fc673412e01a532d 100644
--- a/include/linux/scmi_imx_protocol.h
+++ b/include/linux/scmi_imx_protocol.h

@@ -71,6 +71,23 @@ struct scmi_imx_misc_system_info {
 	u8 siname[MISC_MAX_SINAME];
 };
 
+struct scmi_imx_misc_sys_sleep_rec {
+	u32 sleepentryusec;
+	u32 sleepexitusec;
+	u32 sleepcnt;
+	u32 wakesource;
+	u32 mixpwrstat;
+	u32 mempwrstat;
+	u32 pllpwrstat;
+	u32 syssleepmode;
+	u32 syssleepflags;
+};

So where is this used ? later in the series ?

quoted

+
+struct scmi_imx_misc_syslog {
+	struct scmi_imx_misc_sys_sleep_rec syssleeprecord;

Included here, but used in last patch in the patchset.

quoted

+	uint32_t deverrlog;
+};
+
 struct scmi_imx_misc_proto_ops {
 	int (*misc_cfg_info)(const struct scmi_protocol_handle *ph,
 			     struct scmi_imx_misc_system_info *info);

@@ -84,6 +101,8 @@ struct scmi_imx_misc_proto_ops {
 					struct scmi_imx_misc_system_info *info);
 	int (*misc_silicon_info)(const struct scmi_protocol_handle *ph,
 				 struct scmi_imx_misc_system_info *info);
+	int (*misc_syslog)(const struct scmi_protocol_handle *ph, u16 size,
+			  void *array);
 };

Thanks,
Peng

Thanks,
Cristian