Re: [PATCH v7 4/5] Coresight: Add Coresight TMC Control Unit driver

[Jie Gan <quic_jiegan@quicinc.com>]

On 12/15/2024 6:21 AM, Konrad Dybcio wrote:
> On 10.12.2024 4:15 AM, Jie Gan wrote:
>> The Coresight TMC Control Unit hosts miscellaneous configuration registers
>> which control various features related to TMC ETR sink.
>>
>> Based on the trace ID, which is programmed in the related CTCU ATID
>> register of a specific ETR, trace data with that trace ID gets into
>> the ETR buffer, while other trace data gets dropped.
>>
>> Enabling source device sets one bit of the ATID register based on
>> source device's trace ID.
>> Disabling source device resets the bit according to the source
>> device's trace ID.
>>
>> Signed-off-by: Jie Gan <quic_jiegan@quicinc.com>
>> ---
> 
> [...]
> 
>> +static int __ctcu_set_etr_traceid(struct coresight_device *csdev,
>> +				  u8 traceid,
>> +				  int port_num,
>> +				  bool enable)
>> +{
>> +	uint32_t atid_offset;
>> +	struct ctcu_drvdata *drvdata;
>> +	unsigned long flags;
>> +	uint32_t reg_offset;
>> +	int bit;
>> +	uint32_t val;
>> +
>> +	if (!IS_VALID_CS_TRACE_ID(traceid) || port_num < 0)
>> +		return -EINVAL;
>> +
>> +	drvdata = dev_get_drvdata(csdev->dev.parent);
>> +	if (IS_ERR_OR_NULL(drvdata))
>> +		return -EINVAL;
>> +
>> +	atid_offset = drvdata->atid_offset[port_num];
>> +	if (atid_offset == 0)
>> +		return -EINVAL;
>> +
>> +	spin_lock_irqsave(&drvdata->spin_lock, flags);
> 
> guard(raw_spinlock_irqsave)(&drvdata->spin_lock);
> 
> and drop the unlocks
> 
Sure, will fix in next version.

>> +	CS_UNLOCK(drvdata->base);
>> +
>> +	reg_offset = CTCU_ATID_REG_OFFSET(traceid, atid_offset);
>> +	bit = CTCU_ATID_REG_BIT(traceid);
>> +	if (reg_offset - atid_offset >= CTCU_ATID_REG_SIZE ||
>> +	    bit >= CORESIGHT_TRACE_IDS_MAX) {
>> +		CS_LOCK(drvdata);
>> +		spin_unlock_irqrestore(&drvdata->spin_lock, flags);
>> +		return -EINVAL;
>> +	}
>> +
>> +	val = ctcu_readl(drvdata, reg_offset);
>> +	if (enable)
>> +		val = val | BIT(bit);
>> +	else
>> +		val = val & ~BIT(bit);
>> +	ctcu_writel(drvdata, val, reg_offset);
>> +
>> +	CS_LOCK(drvdata->base);
>> +	spin_unlock_irqrestore(&drvdata->spin_lock, flags);
>> +
>> +	return 0;
>> +}
>> +
>> +static int ctcu_get_active_port(struct coresight_device *sink, struct coresight_device *helper)
>> +{
>> +	int port, i;
>> +
>> +	for (i = 0; i < sink->pdata->nr_outconns; ++i) {
>> +		if (sink->pdata->out_conns[i]->dest_dev) {
>> +			port = sink->pdata->out_conns[i]->dest_port;
>> +			return port;
> 
> Return sink->....
Sure, will fix in next version.

> 
>> +		}
>> +	}
>> +
>> +	return -EINVAL;
>> +}
>> +
>> +/*
>> + * ctcu_set_etr_traceid: Retrieve the ATID offset and trace ID.
>> + *
>> + * Returns 0 indicates success. None-zero result means failure.
>> + */
>> +static int ctcu_set_etr_traceid(struct coresight_device *csdev,
>> +				struct cs_sink_data *sink_data,
>> +				bool enable)
>> +{
>> +	int port_num;
>> +
>> +	if (!IS_VALID_CS_TRACE_ID(sink_data->traceid) ||
>> +	    (csdev == NULL) ||
> 
> I'm not sure this can be null by the time it reaches this function
Will check.

> 
>> +	    (sink_data->sink == NULL)) {
>> +		dev_dbg(&csdev->dev, "Invalid parameters\n");
> 
> dev_err?
It's better with dev_err, will fix.

> 
>> +		return -EINVAL;
>> +	}
>> +
>> +	port_num = ctcu_get_active_port(sink_data->sink, csdev);
>> +	if (port_num < 0)
>> +		return -EINVAL;
>> +
>> +	dev_dbg(&csdev->dev, "traceid is %d\n", sink_data->traceid);
>> +
>> +	return __ctcu_set_etr_traceid(csdev, sink_data->traceid, port_num, enable);
>> +}
>> +
>> +static int ctcu_enable(struct coresight_device *csdev, enum cs_mode mode,
>> +		       void *data)
>> +{
>> +	int ret = 0;
> 
> Unnecessary initialization (you instantly overwrite it), also below
> 
>> +	struct cs_sink_data *sink_data = (struct cs_sink_data *)data;
>> +
>> +	ret = ctcu_set_etr_traceid(csdev, sink_data, true);
>> +	if (ret)
>> +		dev_dbg(&csdev->dev, "enable data filter failed\n");
> 
> Since the this function returns an int, maybe return ctcu_set_etr_traceid()
> and let the upper layer throw an error (also for some other functions in this
> file)
> 
Sure, will check.

>> +
>> +	return 0;
>> +}
>> +
>> +static int ctcu_disable(struct coresight_device *csdev, void *data)
>> +{> +	int ret = 0;
>> +	struct cs_sink_data *sink_data = (struct cs_sink_data *)data;
>> +
>> +	ret = ctcu_set_etr_traceid(csdev, sink_data, false);
>> +	if (ret)
>> +		dev_dbg(&csdev->dev, "disable data filter failed\n");
>> +
>> +	return 0;
>> +}
> 
> [...]
> 
>>   enum coresight_dev_subtype_helper {
>>   	CORESIGHT_DEV_SUBTYPE_HELPER_CATU,
>> -	CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI
>> +	CORESIGHT_DEV_SUBTYPE_HELPER_ECT_CTI,
>> +	CORESIGHT_DEV_SUBTYPE_HELPER_CTCU
> 
> Please add a comma here too, so that future additions will be
> less noisy
Sure, will add a comma after CORESIGHT_DEV_SUBTYPE_HELPER_CTCU.


Thanks,
Jie