Re: [PATCH v5 09/14] coresight: cti: Add connection information to sysfs

[Mike Leach <mike.leach@linaro.org>]

Hi suzuki,

On Mon, 2 Dec 2019 at 09:48, Suzuki Kuruppassery Poulose
<suzuki.poulose@arm.com> wrote:
>
> On 19/11/2019 23:19, Mike Leach wrote:
> > Dynamically adds sysfs attributes for all connections defined in the CTI.
> >
> > Each connection has a triggers<N> sub-directory with name, in_signals,
> > in_types, out_signals and out_types as read-only parameters in the
> > directory. in_ or out_ parameters may be omitted if there are no in or
> > out signals for the connection.
> >
> > Additionally each device has a nr_cons in the connections sub-directory.
> >
> > This allows clients to explore the connection and trigger signal details
> > without needing to refer to device tree or specification of the device.
> >
> > Standardised type information is provided for certain common functions -
> > e.g. snk_full for a trigger from a sink indicating full. Otherwise type
> > defaults to genio.
> >
> > Signed-off-by: Mike Leach <mike.leach@linaro.org>
> > ---
> >   .../hwtracing/coresight/coresight-cti-sysfs.c | 376 +++++++++++++++++-
> >   drivers/hwtracing/coresight/coresight-cti.c   |  13 +-
> >   drivers/hwtracing/coresight/coresight-cti.h   |  11 +-
> >   3 files changed, 396 insertions(+), 4 deletions(-)
> >
>
>
> The patch looks good overall, some minor comments below.
>
>
> > diff --git a/drivers/hwtracing/coresight/coresight-cti-sysfs.c b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > index f800402f73da..91986732506f 100644
> > --- a/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > +++ b/drivers/hwtracing/coresight/coresight-cti-sysfs.c
> > @@ -8,6 +8,67 @@
>
>
> > @@ -818,7 +890,306 @@ static struct attribute *coresight_cti_channel_attrs[] = {
> >       NULL,
> >   };
> >
> > -/* sysfs groups */
> > +/* Create the connections trigger groups and attrs dynamically */
> > +/*
> > + * Each connection has dynamic group triggers<N> + name, trigin/out sigs/types
> > + * attributes, + each device has static nr_trigger_cons giving the number
> > + * of groups. e.g. in sysfs:-
> > + * /cti_<name>/triggers0
> > + * /cti_<name>/triggers1
> > + * /cti_<name>/nr_trigger_cons
> > + * where nr_trigger_cons = 2
> > + */
> > +static ssize_t con_name_show(struct device *dev,
> > +                          struct device_attribute *attr,
> > +                          char *buf)
> > +{
> > +     struct dev_ext_attribute *ext_attr =
> > +             container_of(attr, struct dev_ext_attribute, attr);
> > +     struct cti_trig_con *con = (struct cti_trig_con *)ext_attr->var;
> > +
> > +     return scnprintf(buf, PAGE_SIZE, "%s\n", con->con_dev_name);
> > +}
> > +
> > +static ssize_t trigin_sig_show(struct device *dev,
> > +                            struct device_attribute *attr,
> > +                            char *buf)
> > +{
> > +     struct dev_ext_attribute *ext_attr =
> > +             container_of(attr, struct dev_ext_attribute, attr);
> > +     struct cti_trig_con *con = (struct cti_trig_con *)ext_attr->var;
> > +     struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > +     struct cti_config *cfg = &drvdata->config;
> > +     unsigned long mask = con->con_in->used_mask;
> > +
> > +     return bitmap_print_to_pagebuf(true, buf, &mask, cfg->nr_trig_max);
> > +}
> > +
> > +static ssize_t trigout_sig_show(struct device *dev,
> > +                             struct device_attribute *attr,
> > +                             char *buf)
> > +{
> > +     struct dev_ext_attribute *ext_attr =
> > +             container_of(attr, struct dev_ext_attribute, attr);
> > +     struct cti_trig_con *con = (struct cti_trig_con *)ext_attr->var;
> > +     struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
> > +     struct cti_config *cfg = &drvdata->config;
> > +     unsigned long mask = con->con_out->used_mask;
> > +
> > +     return bitmap_print_to_pagebuf(true, buf, &mask, cfg->nr_trig_max);
> > +}
> > +
> > +/* convert a sig type id to a name */
> > +static const char *
> > +cti_sig_type_name(struct cti_trig_con *con, int used_count, bool in)
> > +{
> > +     int idx = 0;
> > +     struct cti_trig_grp *grp = in ? con->con_in : con->con_out;
> > +
> > +     if (grp->sig_types) {
> > +             if (used_count < grp->nr_sigs)
> > +                     idx = grp->sig_types[used_count];
> > +     }
> > +     return sig_type_names[idx];
> > +}
> > +
> > +static ssize_t trigin_type_show(struct device *dev,
> > +                             struct device_attribute *attr,
> > +                             char *buf)
> > +{
> > +     struct dev_ext_attribute *ext_attr =
> > +             container_of(attr, struct dev_ext_attribute, attr);
> > +     struct cti_trig_con *con = (struct cti_trig_con *)ext_attr->var;
> > +     int sig_idx, used = 0, b_sz = PAGE_SIZE;
> > +     const char *name;
> > +
> > +     for (sig_idx = 0; sig_idx < con->con_in->nr_sigs; sig_idx++) {
> > +             name = cti_sig_type_name(con, sig_idx, true);
> > +             used += scnprintf(buf + used, b_sz - used, "%s ", name);
> > +     }
> > +     used += scnprintf(buf + used, b_sz - used, "\n");
> > +     return used;
> > +}
> > +
> > +static ssize_t trigout_type_show(struct device *dev,
> > +                              struct device_attribute *attr,
> > +                              char *buf)
> > +{
> > +     struct dev_ext_attribute *ext_attr =
> > +             container_of(attr, struct dev_ext_attribute, attr);
> > +     struct cti_trig_con *con = (struct cti_trig_con *)ext_attr->var;
> > +     int sig_idx, used = 0, b_sz = PAGE_SIZE;
> > +     const char *name;
> > +
> > +     for (sig_idx = 0; sig_idx < con->con_out->nr_sigs; sig_idx++) {
> > +             name = cti_sig_type_name(con, sig_idx, false);
> > +             used += scnprintf(buf + used, b_sz - used, "%s ", name);
> > +     }
> > +     used += scnprintf(buf + used, b_sz - used, "\n");
> > +     return used;
> > +}
> > +
> > +/*
> > + * Array of show function names declared above to allow selection
> > + * for the connection attributes
> > + */
> > +static p_show_fn show_fns[CTI_CON_ATTR_MAX] = {
> > +     con_name_show,
> > +     trigin_sig_show,
> > +     trigout_sig_show,
> > +     trigin_type_show,
> > +     trigout_type_show,
> > +};
> > +
> > +static int cti_create_con_sysfs_attr(struct cti_trig_con *con,
> > +                                  enum cti_conn_attr_type attr_type,
> > +                                  int attr_idx)
> > +{
> > +     struct dev_ext_attribute *dev_ext_attr = 0;
>
> super minor nit: You may use "eattr" instead.
>
>
> > +     char *name = 0;
> > +
> > +     dev_ext_attr = kzalloc(sizeof(struct dev_ext_attribute), GFP_KERNEL);
>
>
> Could we not use devm_* alloc helpers everywhere ?

Yes - will change.

>
> > +     if (dev_ext_attr) {
> > +             name = kstrdup(con_attr_names[attr_type], GFP_KERNEL);
> > +             if (name) {
> > +                     /* fill out the underlying attribute struct */
> > +                     dev_ext_attr->attr.attr.name = name;
> > +                     dev_ext_attr->attr.attr.mode = 0444;
> > +
> > +                     /* now the device_attribute struct */
> > +                     dev_ext_attr->attr.show = show_fns[attr_type];
> > +             } else {
> > +                     kfree(dev_ext_attr);
> > +                     return -ENOMEM;
> > +             }
> > +     } else {
> > +             return -ENOMEM;
> > +     }
> > +     dev_ext_attr->var = con;
> > +     con->con_attrs[attr_idx] = &dev_ext_attr->attr.attr;
> > +     return 0;
> > +}
> > +
> > +static struct attribute_group *
> > +cti_create_con_sysfs_group(struct cti_device *ctidev, int con_idx,
> > +                        struct cti_trig_con *con)
> > +{
> > +     struct attribute_group *group = NULL;
> > +
> > +     group = kzalloc(sizeof(struct attribute_group), GFP_KERNEL);
> > +     if (!group)
> > +             return NULL;
> > +
> > +     group->name = kasprintf(GFP_KERNEL, "triggers%d", con_idx);
> > +     if (!group->name) {
> > +             kfree(group);
> > +             return NULL;
> > +     }
> > +
> > +     ctidev->con_groups[con_idx + CORESIGHT_CTI_STATIC_GROUPS_MAX - 1]
> > +             = group;
>
> nit:
>         con_idx +=  CORESIGHT_CTI_STATIC_GROUPS_MAX - 1;
>         ctidev->con_groups[con_idx] = group;
>
OK.
>
> > +     con->attr_group = group;
> > +     return group;
> > +}
> > +
> > +/* create a triggers connection group and the attributes for that group */
> > +static int cti_create_con_attr_set(int con_idx, struct cti_device *ctidev,
> > +                                struct cti_trig_con *con)
> > +{
> > +     struct attribute_group *attr_group = NULL;
> > +     int attr_idx = 0;
> > +     int err = -ENOMEM;
> > +
> > +     attr_group = cti_create_con_sysfs_group(ctidev, con_idx, con);
> > +     if (!attr_group)
> > +             return -ENOMEM;
> > +
> > +     /* allocate NULL terminated array of attributes */
> > +     con->con_attrs = kcalloc(CTI_CON_ATTR_MAX + 1,
> > +                              sizeof(struct attribute *),
> > +                              GFP_KERNEL);
>
> Again why not devm_* allocations ? That takes the pain of freeing the
> memory away and helps prevent memory leaks.
>
> > +     if (!con->con_attrs)
> > +             return -ENOMEM;
> > +
> > +     err = cti_create_con_sysfs_attr(con, CTI_CON_ATTR_NAME, attr_idx++);
> > +     if (err)
> > +             return err;
> > +
> > +     if (con->con_in->nr_sigs > 0) {
> > +             err = cti_create_con_sysfs_attr(con, CTI_CON_ATTR_TRIGIN_SIG,
> > +                                             attr_idx++);
> > +             if (err)
> > +                     return err;
> > +
> > +             err = cti_create_con_sysfs_attr(con, CTI_CON_ATTR_TRIGIN_TYPES,
> > +                                             attr_idx++);
> > +             if (err)
> > +                     return err;
> > +     }
> > +
> > +     if (con->con_in->nr_sigs > 0) {
> > +             err = cti_create_con_sysfs_attr(con, CTI_CON_ATTR_TRIGOUT_SIG,
> > +                                             attr_idx++);
> > +             if (err)
> > +                     return err;
> > +
> > +             err = cti_create_con_sysfs_attr(con, CTI_CON_ATTR_TRIGOUT_TYPES,
> > +                                             attr_idx++);
> > +             if (err)
> > +                     return err;
> > +     }
> > +     attr_group->attrs = con->con_attrs;
> > +     return 0;
> > +}
> > +
> > +/* create the array of group pointers for the CTI sysfs groups */
> > +int cti_create_cons_groups(struct cti_device *ctidev)
> > +{
> > +     int i, nr_groups;
> > +
> > +     /* nr groups - dynamic + static + NULL terminator */
> > +     nr_groups = ctidev->nr_trig_con + CORESIGHT_CTI_STATIC_GROUPS_MAX;
> > +     ctidev->con_groups = kcalloc(nr_groups,
> > +                                  sizeof(struct attribute_group *),
> > +                                  GFP_KERNEL);
> > +     if (!ctidev->con_groups)
> > +             return -ENOMEM;
> > +
> > +     /* populate first locations with the static set of groups */
> > +     for (i = 0; i < (CORESIGHT_CTI_STATIC_GROUPS_MAX - 1); i++)
> > +             ctidev->con_groups[i] = coresight_cti_groups[i];
> > +
> > +     return 0;
> > +}
> > +
>
> To be frank, it doesn't make sense to have this split of populating
> the groups.
Moved to caller.

>
> > +int cti_create_cons_sysfs(struct cti_drvdata *drvdata)
> > +{
> > +     struct cti_device *ctidev = &drvdata->ctidev;
> > +     int err, con_idx = 0;
> > +     struct cti_trig_con *tc = NULL;
> > +
> > +     err = cti_create_cons_groups(ctidev);
> > +     if (err)
> > +             return err;
> > +
> > +     /* add dynamic set for each connection */
> > +     list_for_each_entry(tc, &ctidev->trig_cons, node) {
> > +             err = cti_create_con_attr_set(con_idx++, ctidev, tc);
> > +             if (err)
> > +                     goto cons_sysfs_err;
> > +     }
> > +     return 0;
> > +
> > +cons_sysfs_err:
> > +     cti_destroy_cons_sysfs(ctidev);
> > +     return err;
> > +}
> > +
> > +void cti_free_con_attr(struct attribute *con_attr)
> > +{
> > +     struct device_attribute *dattr =
> > +             container_of(con_attr, struct device_attribute, attr);
> > +     struct dev_ext_attribute *dev_ext_attr =
> > +             container_of(dattr, struct dev_ext_attribute, attr);
> > +     kfree(con_attr->name);
> > +     kfree(dev_ext_attr);
> > +}
> > +
> > +void cti_free_con_group(struct attribute_group *attr_group)
> > +{
> > +     if (attr_group) {
> > +             kfree(attr_group->name);
> > +             kfree(attr_group);
> > +     }
> > +}
> > +
> > +void cti_destroy_cons_attr_set(int con_idx, struct cti_device *ctidev,
> > +                            struct cti_trig_con *con)
> > +{
> > +     int i;
> > +
> > +     if (con->con_attrs) {
> > +             for (i = 0; i < CTI_CON_ATTR_MAX; i++) {
> > +                     if (con->con_attrs[i])
> > +                             cti_free_con_attr(con->con_attrs[i]);
> > +             }
> > +             kfree(con->con_attrs);
> > +     }
> > +     cti_free_con_group(con->attr_group);
> > +}
> > +
> > +void cti_destroy_cons_sysfs(struct cti_device *ctidev)
> > +{
> > +     struct cti_trig_con *tc;
>
> minor nit: Please keep the variable name consistent if possible, helps a
> lot with the code following. i.e, tc vs con above in
> cti_destroy_cons_attr_set().

OK
>
> > +     int con_idx = 0;
> > +
> > +     list_for_each_entry(tc, &ctidev->trig_cons, node) {
> > +             cti_destroy_cons_attr_set(con_idx++, ctidev, tc);
> > +     }
> > +     kfree(ctidev->con_groups);
> > +}
> > +
> > +/* attribute and group sysfs tables. */
> >   static const struct attribute_group coresight_cti_group = {
> >       .attrs = coresight_cti_attrs,
> >   };
> > @@ -838,7 +1209,8 @@ static const struct attribute_group coresight_cti_channels_group = {
> >       .name = "channels",
> >   };
> >
> > -const struct attribute_group *coresight_cti_groups[] = {
> > +const struct attribute_group *
> > +coresight_cti_groups[CORESIGHT_CTI_STATIC_GROUPS_MAX] = {
> >       &coresight_cti_group,
> >       &coresight_cti_mgmt_group,
> >       &coresight_cti_regs_group,
> > diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
> > index cf116463149a..c3d63cc53bdd 100644
> > --- a/drivers/hwtracing/coresight/coresight-cti.c
> > +++ b/drivers/hwtracing/coresight/coresight-cti.c
> > @@ -561,6 +561,9 @@ static void cti_device_release(struct device *dev)
> >
> >       mutex_lock(&ect_mutex);
> >
> > +     /* clear the dynamic sysfs associate with connections */
> > +     cti_destroy_cons_sysfs(&drvdata->ctidev);
> > +
> >       /* remove from the list */
> >       list_for_each_entry_safe(ect_item, ect_tmp, &ect_net, node) {
> >               if (ect_item == drvdata) {
> > @@ -636,12 +639,20 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
> >               goto err_out;
> >       }
> >
> > +     /* create dynamic attributes for connections */
> > +     ret = cti_create_cons_sysfs(drvdata);
> > +     if (ret) {
> > +             pr_err("%s: create dynamic sysfs entries failed\n",
> > +                    cti_desc.name);
>
> nit: It may be a good idea to include the actual device name (rather
> than just cti_xxx). so may be :
>
>   dev_err(dev, "%s:....", cti_desc.name) ?
>
>
> > +             goto err_out;
> > +     }
>
>
> Except for the devm_ alloc question, rest are fine.
>
> Suzuki

Thanks

Mike

-- 
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK