Re: [PATCH 7/7] firmware: imx: sm-misc: Dump syslog and system info

Peng Fan
2025-06-30T02:24:22Z

On Fri, Jun 27, 2025 at 03:11:03PM +0100, Cristian Marussi wrote:
>On Fri, Jun 27, 2025 at 02:03:50PM +0800, Peng Fan wrote:
>> Add sysfs interface to read System Manager syslog and system info
>>
>> Signed-off-by: Peng Fan <peng.fan@nxp.com>
>> ---
>> drivers/firmware/imx/sm-misc.c | 97 ++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 97 insertions(+)
>>
>> diff --git a/drivers/firmware/imx/sm-misc.c b/drivers/firmware/imx/sm-misc.c
>> index fc3ee12c2be878e0285183e3381c9514a63d5142..55485a3c4a5c615102a377f41025a6911d746770 100644
>> --- a/drivers/firmware/imx/sm-misc.c
>> +++ b/drivers/firmware/imx/sm-misc.c
>> @@ -44,6 +44,100 @@ static int scmi_imx_misc_ctrl_notifier(struct notifier_block *nb,
>> return 0;
>> }
>>
>> +static ssize_t syslog_show(struct device *device, struct device_attribute *attr,
>> + char *buf)
>> +{
>> + struct scmi_imx_misc_sys_sleep_rec *rec;
>> + struct scmi_imx_misc_syslog *syslog;
>> + int ret;
>> + size_t len = 0;
>> +
>> + if (!ph)
>> + return 0;
>> +
>> + syslog = kmalloc(sizeof(*syslog), GFP_KERNEL);
>> + if (!syslog)
>> + return -ENOMEM;
>> +
>> + ret = imx_misc_ctrl_ops->misc_syslog(ph, sizeof(*syslog), syslog);
>
>...ah...so you basically cast to void a structure of u32 words and then
>expect that the firmware perfectly aligned with how the struct is
>defined here....size checks assures no out-of-bounds BUT the meaning of
>he blob itself is entirely up to FW and kernel being aligned, since no
>type checking is done of any kind and fields are NOT reference by
>name...so may I ask why ?

I thought to use "u32 *syslog", but this needs a cast in
misc_syslog(x,y,(u32 *)syslog), or I could directly change
the misc_syslog function prototype to use 'struct scmi_imx_misc_syslog *'.
No specific reason, just think 'void *' could avoid a cast.

..also because the scmi_imx_misc_syslog seems
>pretty tiny to need iterators to parse back the reply...do you have so
>tiny transpotr message size ?

The transport memory size is 0x80 bytes, it could cover the current
syslog, but I am not sure whether in future, the firmware could
extend to add more information.

In our firmware there is one more field that I not include in this patchset,
because it is default not built in in firmware:
typedef struct
{
/*! System sleep record */
dev_sm_sys_sleep_rec_t sysSleepRecord;

/*! Device error log */
uint32_t devErrLog;

#ifdef DEV_SM_MSG_PROF_CNT
/*! Message profiling record */
dev_sm_sys_msg_rec_t sysMsgRecord;
#endif
} dev_sm_syslog_t;

typedef struct
{
uint32_t scmiChannel; /*!< Caller SCMI channel */
uint32_t chanType; /*!< SCMI channel type */
uint32_t protocolId; /*!< SCMI protocol ID */
uint32_t msgId; /*!< SCMI message ID */
uint32_t msgLatUsec; /*!< Message latency */
} dev_sm_sys_msg_prof_t;

/*!
* Message profile record
*/
typedef struct
{
/*! MSG profile log */
dev_sm_sys_msg_prof_t msgProf[DEV_SM_MSG_PROF_CNT];
} dev_sm_sys_msg_rec_t;

With profiling, we need iterator to get all the information.

In our default FW build, DEV_SM_MSG_PROF_CNT is not defined, but
I could keep iterator in case DEV_SM_MSG_PROF_CNT enabled in future.

>
>..anyway I would suggest at least to add some sort of version-field to
>the struct so that at least you can detect if the FW spits out something
>that is not what your driver expect or is ready to handle...especially
>if you plan to extend or modify the layout of the structs in the future.

Would you please share more insights on what version is needed here?
You mean add a field for syslog protocol as below?
struct scmi_imx_misc_syslog {
uint32_t version; //Set as protocol version and display it in sysfs show ops?
struct scmi_imx_misc_sys_sleep_rec syssleeprecord;
uint32_t deverrlog;
};

>
>
>> + if (ret) {
>> + kfree(syslog);
>> + return ret;
>> + }
>> +
>> + rec = &syslog->syssleeprecord;
>> +
>> + len += sysfs_emit_at(buf, len, "Wake Vector = %u\n", rec->wakesource);
>> + len += sysfs_emit_at(buf, len, "Sys sleep mode = %u\n", rec->syssleepmode);
>> + len += sysfs_emit_at(buf, len, "Sys sleep flags = 0x%08x\n", rec->syssleepflags);
>> + len += sysfs_emit_at(buf, len, "MIX power status = 0x%08x\n", rec->mixpwrstat);
>> + len += sysfs_emit_at(buf, len, "MEM power status = 0x%08x\n", rec->mempwrstat);
>> + len += sysfs_emit_at(buf, len, "PLL power status = 0x%08x\n", rec->pllpwrstat);
>> + len += sysfs_emit_at(buf, len, "Sleep latency = %u\n", rec->sleepentryusec);
>> + len += sysfs_emit_at(buf, len, "Wake latency = %u\n", rec->sleepexitusec);
>> + len += sysfs_emit_at(buf, len, "Sleep count = %u\n", rec->sleepcnt);
>> +
>
>... how wonder how much is still frowned upon to serve such big multiline
>structured information payloads from sysfs ... (asking for a friend :P)

Just take what our firmware console displays.

And in case the firmware does not have a dedicated uart on some
boards, using syslog to show similar info would be prefered,
so ...

>
>
>> + kfree(syslog);
>> +
>> + return len;
>> +}
>> +
>> +static DEVICE_ATTR_RO(syslog);
>> +
>> +static ssize_t system_info_show(struct device *device, struct device_attribute *attr,
>> + char *buf)
>> +{
>> + struct scmi_imx_misc_system_info *info;
>> + int len = 0;
>> + int ret;
>> +
>> + if (!ph)
>> + return 0;
>> +
>> + info = kmalloc(sizeof(*info), GFP_KERNEL);
>> + if (!info)
>> + return -ENOMEM;
>> +
>> + ret = imx_misc_ctrl_ops->misc_discover_build_info(ph, info);
>> + if (ret)
>> + goto err;
>> +
>> + ret = imx_misc_ctrl_ops->misc_cfg_info(ph, info);
>> + if (ret)
>> + goto err;
>> +
>> + ret = imx_misc_ctrl_ops->misc_silicon_info(ph, info);
>> + if (ret)
>> + goto err;
>> +
>> + ret = imx_misc_ctrl_ops->misc_board_info(ph, info);
>> + if (ret)
>> + goto err;
>> +
>> + len += sysfs_emit_at(buf, len, "SM Version = Build %u, Commit 08%x\n",
>> + info->buildnum, info->buildcommit);
>> + len += sysfs_emit_at(buf, len, "SM Config = %s, mSel=%u\n",
>> + info->cfgname, info->msel);
>> + len += sysfs_emit_at(buf, len, "Silicon = %s\n", info->siname);
>> + len += sysfs_emit_at(buf, len, "Board = %s, attr=0x%08x\n",
>> + info->brdname, info->brd_attributes);
>
>...so some of this stuff Build/Silicon/BoaRD info has pretty much
>'forever' lifetime...are you sure you want to query them out of the FW
>each time you issue a sysfs show ?
>
>Cannot you simply dump this stuff once for all at probve time and
>instead query misc_cfg_info() upon each show to refresh only the data
>that will change ?
>
>(this also corroborates my idea that you should somehow partition this
>data into distinct structs by their lifetime...

In next version, I will change to use probe to query the information and
use sysfs to give userspace an interface to get the queried information.

Thanks,
Peng

>
>Thanks,
>Cristian