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

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

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

> +	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->....

> +		}
> +	}
> +
> +	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

> +	    (sink_data->sink == NULL)) {
> +		dev_dbg(&csdev->dev, "Invalid parameters\n");

dev_err?

> +		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)

> +
> +	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