Re: [PATCH 04/10] Coresight: Enable BC and GPR for TPDM driver

From: Mathieu Poirier
Date: Thu Nov 04 2021 - 13:02:33 EST


[...]

> > > +
> > > +static ssize_t reset_store(struct device *dev,
> > > + struct device_attribute *attr,
> > > + const char *buf,
> > > + size_t size)
> > > +{
> > > + int ret = 0;
> > > + unsigned long val;
> > > + struct mcmb_dataset *mcmb_temp = NULL;
> > > + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > > +
> > > + ret = kstrtoul(buf, 10, &val);
> >
> > The coresight subsystem normally uses the hexadecimal base.
> >
>
> We will address you comments.
>
> > > + if (ret)
> > > + return ret;
> >
> > Shouldn't this be "if (!ret)" ?
> >
>
> When ret is not 0, it need to return.

I would expect something like this:

$ echo 1 > /sys/path/to/tpdm/device/reset

and not

$ echo 0 > /sys/path/to/tpdm/device/reset

The latter is what the code does.

Thanks,
Mathieu

>
> > > +
> > > + mutex_lock(&drvdata->lock);
> > > + /* Reset all datasets to ZERO */
> > > + if (drvdata->gpr != NULL)
> > > + memset(drvdata->gpr, 0, sizeof(struct gpr_dataset));
> > > +
> > > + if (drvdata->bc != NULL)
> > > + memset(drvdata->bc, 0, sizeof(struct bc_dataset));
> > > +
> > > + if (drvdata->tc != NULL)
> > > + memset(drvdata->tc, 0, sizeof(struct tc_dataset));
> > > +
> > > + if (drvdata->dsb != NULL)
> > > + memset(drvdata->dsb, 0, sizeof(struct dsb_dataset));
> > > +
> > > + if (drvdata->cmb != NULL) {
> > > + if (drvdata->cmb->mcmb != NULL) {
> > > + mcmb_temp = drvdata->cmb->mcmb;
> > > + memset(drvdata->cmb->mcmb, 0,
> > > + sizeof(struct mcmb_dataset));
> > > + }
> > > +
> > > + memset(drvdata->cmb, 0, sizeof(struct cmb_dataset));
> > > + drvdata->cmb->mcmb = mcmb_temp;
> > > + }
> > > + /* Init the default data */
> > > + tpdm_init_default_data(drvdata);
> > > +
> > > + mutex_unlock(&drvdata->lock);
> > > +
> > > + /* Disable tpdm if enabled */
> > > + if (drvdata->enable)
> > > + coresight_disable(drvdata->csdev);
> >
> > Why is this done out of the lock?
> >
>
> When call coresight_disable, tpdm_disable will be called. There is lock in tpdm_disable.
> If add it into the lock, there will be dead lock.
>
> > > +
> > > + return size;
> > > +}
> > > +static DEVICE_ATTR_WO(reset);
> > > +
> > > +static ssize_t integration_test_store(struct device *dev,
> > > + struct device_attribute *attr,
> > > + const char *buf,
> > > + size_t size)
> > > +{
> > > + int i, ret = 0;
> > > + unsigned long val;
> > > + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > > +
> > > + ret = kstrtoul(buf, 10, &val);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + if (val != 1 && val != 2)
> > > + return -EINVAL;
> > > +
> > > + if (!drvdata->enable)
> > > + return -EINVAL;
> > > +
> > > + if (val == 1)
> > > + val = ATBCNTRL_VAL_64;
> > > + else
> > > + val = ATBCNTRL_VAL_32;
> > > + TPDM_UNLOCK(drvdata);
> > > + tpdm_writel(drvdata, 0x1, TPDM_ITCNTRL);
> > > +
> > > + for (i = 1; i < 5; i++)
> > > + tpdm_writel(drvdata, val, TPDM_ITATBCNTRL);
> > > +
> > > + tpdm_writel(drvdata, 0, TPDM_ITCNTRL);
> > > + TPDM_LOCK(drvdata);
> > > + return size;
> > > +}
> > > +static DEVICE_ATTR_WO(integration_test);
> >
> > Integration test interface should be conditional to a compile time option. Have
> > a look at what was done for CTIs.
> >
>
> We will check and update.
>
> > > +
> > > +static ssize_t gp_regs_show(struct device *dev,
> > > + struct device_attribute *attr,
> > > + char *buf)
> > > +{
> > > + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > > + ssize_t size = 0;
> > > + int i = 0;
> > > +
> > > + if (!test_bit(TPDM_DS_GPR, drvdata->datasets))
> > > + return -EPERM;
> >
> > return -EINVAL;
> >
> > > +
> > > + mutex_lock(&drvdata->lock);
> > > + for (i = 0; i < TPDM_GPR_REGS_MAX; i++) {
> > > + if (!test_bit(i, drvdata->gpr->gpr_dirty))
> > > + continue;
> > > + size += scnprintf(buf + size, PAGE_SIZE - size,
> > > + "Index: 0x%x Value: 0x%x\n", i,
> > > + drvdata->gpr->gp_regs[i]);
> >
> > This should not be - the sysfs interface requires outputs of a single line.
> >
>
> We will check and update.
>
> > > + }
> > > + mutex_unlock(&drvdata->lock);
> > > + return size;
> > > +}
> > > +
> > > +static ssize_t gp_regs_store(struct device *dev,
> > > + struct device_attribute *attr,
> > > + const char *buf,
> > > + size_t size)
> > > +{
> > > + struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > > + unsigned long index, val;
> > > +
> > > + if (sscanf(buf, "%lx %lx", &index, &val) != 2)
> > > + return -EINVAL;
> > > + if (!test_bit(TPDM_DS_GPR, drvdata->datasets) ||
> > > + index >= TPDM_GPR_REGS_MAX)
> > > + return -EPERM;
> > > +
> > > + mutex_lock(&drvdata->lock);
> > > + drvdata->gpr->gp_regs[index] = val;
> > > + __set_bit(index, drvdata->gpr->gpr_dirty);
> > > + mutex_unlock(&drvdata->lock);
> > > + return size;
> > > +}
> > > +static DEVICE_ATTR_RW(gp_regs);
> > > +
> > > +static struct attribute *tpdm_attrs[] = {
> > > + &dev_attr_available_datasets.attr,
> > > + &dev_attr_enable_datasets.attr,
> > > + &dev_attr_reset.attr,
> > > + &dev_attr_integration_test.attr,
> > > + &dev_attr_gp_regs.attr,
> > > + NULL,
> > > +};
> >
> > All new sysfs interface need to be documented. See here:
> >
> > Documentation/ABI/testing/sysfs-bus-coresight-devices-xyz
> >
> > More comments to come...
> >
>
> We will add the comments.
>
> > Thanks,
> > Mathieu
> >
> > > +
> > > +static struct attribute_group tpdm_attr_grp = {
> > > + .attrs = tpdm_attrs,
> > > +};
> > > +static const struct attribute_group *tpdm_attr_grps[] = {
> > > + &tpdm_attr_grp,
> > > + NULL,
> > > +};
> > > +
> > > static int tpdm_datasets_alloc(struct tpdm_drvdata *drvdata)
> > > {
> > > if (test_bit(TPDM_DS_GPR, drvdata->datasets)) {
> > > @@ -513,6 +846,7 @@ static int tpdm_probe(struct amba_device *adev, const struct amba_id *id)
> > > desc.ops = &tpdm_cs_ops;
> > > desc.pdata = adev->dev.platform_data;
> > > desc.dev = &adev->dev;
> > > + desc.groups = tpdm_attr_grps;
> > > drvdata->csdev = coresight_register(&desc);
> > > if (IS_ERR(drvdata->csdev))
> > > return PTR_ERR(drvdata->csdev);
> > > --
> > > 2.17.1
> > >