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

[Peng Fan <peng.fan@oss.nxp.com>]

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:
>> 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...
>
>> +	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
>
>> +	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 ?
>> +
>> +struct scmi_imx_misc_syslog {
>> +	struct scmi_imx_misc_sys_sleep_rec syssleeprecord;

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

>> +	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