On Tue, Feb 11, 2020 at 10:58:05AM +0000, Mike Leach wrote:
> To allow the connections between coresight components to be represented
> in sysfs, generic methods for creating sysfs links between two coresight
> devices are added.
>
> Signed-off-by: Mike Leach <mike.leach@xxxxxxxxxx>
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> ---
> drivers/hwtracing/coresight/Makefile | 3 +-
> drivers/hwtracing/coresight/coresight-priv.h | 4 +
> drivers/hwtracing/coresight/coresight-sysfs.c | 124 ++++++++++++++++++
> include/linux/coresight.h | 20 +++
> 4 files changed, 150 insertions(+), 1 deletion(-)
> create mode 100644 drivers/hwtracing/coresight/coresight-sysfs.c
>
> diff --git a/drivers/hwtracing/coresight/Makefile b/drivers/hwtracing/coresight/Makefile
> index 0e3e72f0f510..19497d1d92bf 100644
> --- a/drivers/hwtracing/coresight/Makefile
> +++ b/drivers/hwtracing/coresight/Makefile
> @@ -2,7 +2,8 @@
> #
> # Makefile for CoreSight drivers.
> #
> -obj-$(CONFIG_CORESIGHT) += coresight.o coresight-etm-perf.o coresight-platform.o
> +obj-$(CONFIG_CORESIGHT) += coresight.o coresight-etm-perf.o \
> + coresight-platform.o coresight-sysfs.o
> obj-$(CONFIG_CORESIGHT_LINK_AND_SINK_TMC) += coresight-tmc.o \
> coresight-tmc-etf.o \
> coresight-tmc-etr.o
> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> index 1cad642f27aa..a4a658d46045 100644
> --- a/drivers/hwtracing/coresight/coresight-priv.h
> +++ b/drivers/hwtracing/coresight/coresight-priv.h
> @@ -153,6 +153,10 @@ struct coresight_device *coresight_get_sink_by_id(u32 id);
> struct list_head *coresight_build_path(struct coresight_device *csdev,
> struct coresight_device *sink);
> void coresight_release_path(struct list_head *path);
> +int coresight_add_sysfs_link(struct coresight_sysfs_link *info);
> +void coresight_remove_sysfs_link(struct coresight_sysfs_link *info);
> +int coresight_create_conns_sysfs_group(struct coresight_device *csdev);
> +void coresight_remove_conns_sysfs_group(struct coresight_device *csdev);
>
> #ifdef CONFIG_CORESIGHT_SOURCE_ETM3X
> extern int etm_readl_cp14(u32 off, unsigned int *val);
> diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
> new file mode 100644
> index 000000000000..17d565941e5e
> --- /dev/null
> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
> @@ -0,0 +1,124 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2019, Linaro Limited, All rights reserved.
> + * Author: Mike Leach <mike.leach@xxxxxxxxxx>
> + */
> +
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +
> +#include "coresight-priv.h"
> +
> +/*
> + * Connections group - links attribute.
> + * Count of created links between coresight components in the group.
> + */
> +static ssize_t nr_links_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct coresight_device *csdev = to_coresight_device(dev);
> +
> + return scnprintf(buf, PAGE_SIZE, "%d\n", csdev->nr_links);
> +}
> +static DEVICE_ATTR_RO(nr_links);
> +
> +static struct attribute *coresight_conns_attrs[] = {
> + &dev_attr_nr_links.attr,
> + NULL,
> +};
> +
> +static struct attribute_group coresight_conns_group = {
> + .attrs = coresight_conns_attrs,
> + .name = "connections",
> +};
> +
> +/*
> + * Create connections group for CoreSight devices.
> + * This group will then be used to collate the sysfs links between
> + * devices.
> + */
> +int coresight_create_conns_sysfs_group(struct coresight_device *csdev)
> +{
> + int ret = 0;
> +
> + if (!csdev)
> + return -EINVAL;
> +
> + ret = sysfs_create_group(&csdev->dev.kobj, &coresight_conns_group);
> + if (ret)
> + return ret;
> +
> + csdev->has_conns_grp = true;
The only place coresight_create_conns_sysfs_group() is used is in
coresight_register() where an error is returned to driver probe() functions if
an error occurs. Have you found places where csdev->has_conns_grp is needed?
If not please remove.
> + return ret;
> +}
> +
> +void coresight_remove_conns_sysfs_group(struct coresight_device *csdev)
> +{
> + if (!csdev)
> + return;
> +
> + if (csdev->has_conns_grp) {
> + sysfs_remove_group(&csdev->dev.kobj, &coresight_conns_group);
> + csdev->has_conns_grp = false;
> + }
> +}
> +
> +int coresight_add_sysfs_link(struct coresight_sysfs_link *info)
> +{
> + int ret = 0;
> +
> + if (!info)
> + return -EINVAL;
> + if (!info->orig || !info->target ||
> + !info->orig_name || !info->target_name)
> + return -EINVAL;
> + if (!info->orig->has_conns_grp || !info->target->has_conns_grp)
> + return -EINVAL;
> +
> + /* first link orig->target */
> + ret = sysfs_add_link_to_group(&info->orig->dev.kobj,
> + coresight_conns_group.name,
> + &info->target->dev.kobj,
> + info->orig_name);
> + if (ret)
> + return ret;
> +
> + /* second link target->orig */
> + ret = sysfs_add_link_to_group(&info->target->dev.kobj,
> + coresight_conns_group.name,
> + &info->orig->dev.kobj,
> + info->target_name);
> +
> + /* error in second link - remove first - otherwise inc counts */
> + if (ret) {
> + sysfs_remove_link_from_group(&info->orig->dev.kobj,
> + coresight_conns_group.name,
> + info->orig_name);
> + } else {
> + info->orig->nr_links++;
> + info->target->nr_links++;
> + }
> +
> + return ret;
> +}
> +
> +void coresight_remove_sysfs_link(struct coresight_sysfs_link *info)
> +{
> + if (!info)
> + return;
> + if (!info->orig || !info->target ||
> + !info->orig_name || !info->target_name)
> + return;
> +
> + sysfs_remove_link_from_group(&info->orig->dev.kobj,
> + coresight_conns_group.name,
> + info->orig_name);
> +
> + sysfs_remove_link_from_group(&info->target->dev.kobj,
> + coresight_conns_group.name,
> + info->target_name);
> +
> + info->orig->nr_links--;
> + info->target->nr_links--;
> +}
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index 193cc9dbf448..a2ec25e02ca9 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -148,6 +148,20 @@ struct coresight_connection {
> struct coresight_device *child_dev;
> };
>
> +/**
> + * struct coresight_sysfs_link - representation of a connection in sysfs.
> + * @orig: Originating (master) coresight device for the link.
> + * @orig_name: Name to use for the link orig->target.
> + * @target: Target (slave) coresight device for the link.
> + * @target_name: Name to use for the link target->orig.
> + */
> +struct coresight_sysfs_link {
> + struct coresight_device *orig;
> + const char *orig_name;
> + struct coresight_device *target;
> + const char *target_name;
> +};
> +
> /**
> * struct coresight_device - representation of a device as used by the framework
> * @pdata: Platform data with device connections associated to this device.
> @@ -165,6 +179,9 @@ struct coresight_connection {
> * @ea: Device attribute for sink representation under PMU directory.
> * @ect_dev: Associated cross trigger device. Not part of the trace data
> * path or connections.
> + * @nr_links: number of sysfs links created to other components from this
> + * device. These will appear in the "connections" group.
> + * @has_conns_grp: Have added a "connections" group for sysfs links.
> */
> struct coresight_device {
> struct coresight_platform_data *pdata;
> @@ -180,6 +197,9 @@ struct coresight_device {
> struct dev_ext_attribute *ea;
> /* cross trigger handling */
> struct coresight_device *ect_dev;
> + /* sysfs links between components */
> + int nr_links;
> + bool has_conns_grp;
> };
With the above:
Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
>
> /*
> --
> 2.17.1
>
