Re: [PATCH v5 04/14] coresight: cti: Add sysfs trigger / channel programming API

On 19/11/2019 23:19, Mike Leach wrote:

Adds a user API to allow programming of CTI by trigger ID and channel number. This will take the channel and trigger ID supplied by the user and program the appropriate register values.

Signed-off-by: Mike Leach mike.leach@linaro.org

+static ssize_t chan_xtrigs_view_show(struct device *dev,

• 		     struct device_attribute *attr,
  

• 		     char *buf)
  

+{

• struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
• struct cti_config *cfg = &drvdata->config;
• int used = 0, reg_idx;
• int buf_sz = PAGE_SIZE;
• u32 chan_mask = BIT(cfg->xtrig_rchan_sel);
• used += scnprintf(buf, buf_sz, "[%d] IN: ", cfg->xtrig_rchan_sel);
• for (reg_idx = 0;

•     reg_idx < drvdata->config.nr_trig_max;
  

•     reg_idx++) {
  

• if (chan_mask & cfg->ctiinen[reg_idx]) {
  

• 	used += scnprintf(buf + used, buf_sz - used, "%d ",
  

• 			  reg_idx);
  

• }
  

• }

As a security measure, we must make sure that we have space left in the buffer. We could end up passing "negative" numbers for the size argument, in the worst case.

• used += scnprintf(buf + used, buf_sz - used, "OUT: ");
• for (reg_idx = 0;

•     reg_idx < drvdata->config.nr_trig_max;
  

•     reg_idx++) {
  

• if (chan_mask & cfg->ctiouten[reg_idx]) {
  

• 	used += scnprintf(buf + used, buf_sz - used, "%d ",
  

• 			  reg_idx);
  

• }
  

• }
• used += scnprintf(buf + used, buf_sz - used, "\n");
• return used;

+} +static DEVICE_ATTR_RW(chan_xtrigs_view);

The rest looks fine to me.

Suzuki