Hi Mike,
On Tue, Feb 11, 2020 at 10:58:06AM +0000, Mike Leach wrote:
> From: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>
> Coresight device connections are a bit complicated and is not
> exposed currently to the user. One has to look at the platform
> descriptions (DT bindings or ACPI bindings) to make an understanding.
> Given the new naming scheme, it will be helpful to have this information
> to choose the appropriate devices for tracing. This patch exposes
> the device connections via links in the sysfs directories.
>
> e.g, for a connection devA[OutputPort_X] -> devB[InputPort_Y]
> is represented as two symlinks:
>
> /sys/bus/coresight/.../devA/out:X -> /sys/bus/coresight/.../devB
> /sys/bus/coresight/.../devB/in:Y -> /sys/bus/coresight/.../devA
>
> Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
>
> Revised to use the generic sysfs links functions & link structures.
> Provides a connections sysfs group to hold the links.
>
> Co-developed-by: Mike Leach <mike.leach@xxxxxxxxxx>
> Signed-off-by: Mike Leach <mike.leach@xxxxxxxxxx>
Because this patch is "From:" Suzuki, this should be:
Co-developed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Signed-off-by: Mike Leach <mike.leach@xxxxxxxxxx>
You can expand on Suzuki's contribution or the modifications you've done to it
in the changelog.
With the above:
Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> ---
> drivers/hwtracing/coresight/coresight-priv.h | 5 ++
> drivers/hwtra cing/coresight/coresight-sysfs.c | 80 +++++++++++++++++++
> drivers/hwtracing/coresight/coresight.c | 46 ++++++++---
> include/linux/coresight.h | 2 +
> 4 files changed, 121 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> index a4a658d46045..5a36f0f50899 100644
> --- a/drivers/hwtracing/coresight/coresight-priv.h
> +++ b/drivers/hwtracing/coresight/coresight-priv.h
> @@ -157,6 +157,11 @@ 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);
> +int coresight_make_links(struct coresight_device *orig,
> + struct coresight_connection *conn,
> + struct coresight_device *target);
> +void coresight_remove_links(struct coresight_device *orig,
> + struct coresight_connection *conn);
>
> #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
> index 17d565941e5e..0f18332b9f19 100644
> --- a/drivers/hwtracing/coresight/coresight-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
> @@ -122,3 +122,83 @@ void coresight_remove_sysfs_link(struct coresight_sysfs_link *info)
> info->orig->nr_links--;
> info->target->nr_links--;
> }
> +
> +/*
> + * coresight_make_links: Make a link for a connection from a @orig
> + * device to @target, represented by @conn.
> + *
> + * e.g, for devOrig[output_X] -> devTarget[input_Y] is represented
> + * as two symbolic links :
> + *
> + * /sys/.../devOrig/out:X -> /sys/.../devTarget/
> + * /sys/.../devTarget/in:Y -> /sys/.../devOrig/
> + *
> + * The link names are allocated for a device where it appears. i.e, the
> + * "out" link on the master and "in" link on the slave device.
> + * The link info is stored in the connection record for avoiding
> + * the reconstruction of names for removal.
> + */
> +int coresight_make_links(struct coresight_device *orig,
> + struct coresight_connection *conn,
> + struct coresight_device *target)
> +{
> + int ret = -ENOMEM;
> + char *outs = NULL, *ins = NULL;
> + struct coresight_sysfs_link *link = NULL;
> +
> + do {
> + outs = devm_kasprintf(&orig->dev, GFP_KERNEL,
> + "out:%d", conn->outport);
> + if (!outs)
> + break;
> + ins = devm_kasprintf(&target->dev, GFP_KERNEL,
> + "in:%d", conn->child_port);
> + if (!ins)
> + break;
> + link = devm_kzalloc(&orig->dev,
> + sizeof(struct coresight_sysfs_link),
> + GFP_KERNEL);
> + if (!link)
> + break;
> +
> + link->orig = orig;
> + link->target = target;
> + link->orig_name = outs;
> + link->target_name = ins;
> +
> + ret = coresight_add_sysfs_link(link);
> + if (ret)
> + break;
> +
> + conn->link = link;
> +
> + /*
> + * Install the device connection. This also indicates that
> + * the links are operational on both ends.
> + */
> + conn->child_dev = target;
> + return 0;
> + } while (0);
> +
> + return ret;
> +}
> +
> +/*
> + * coresight_remove_links: Remove the sysfs links for a given connection @conn,
> + * from @orig device to @target device. See coresight_make_links() for more
> + * details.
> + */
> +void coresight_remove_links(struct coresight_device *orig,
> + struct coresight_connection *conn)
> +{
> + if (!orig || !conn->link)
> + return;
> +
> + coresight_remove_sysfs_link(conn->link);
> +
> + devm_kfree(&conn->child_dev->dev, conn->link->target_name);
> + devm_kfree(&orig->dev, conn->link->orig_name);
> + devm_kfree(&orig->dev, conn->link);
> + conn->link = NULL;
> + conn->child_dev = NULL;
> +}
> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
> index 07f66a3968f1..4f10cfa9dc18 100644
> --- a/drivers/hwtracing/coresight/coresight.c
> +++ b/drivers/hwtracing/coresight/coresight.c
> @@ -1031,7 +1031,7 @@ static void coresight_device_release(struct device *dev)
>
> static int coresight_orphan_match(struct device *dev, void *data)
> {
> - int i;
> + int i, ret = 0;
> bool still_orphan = false;
> struct coresight_device *csdev, *i_csdev;
> struct coresight_connection *conn;
> @@ -1056,19 +1056,23 @@ static int coresight_orphan_match(struct device *dev, void *data)
> /* We have found at least one orphan connection */
> if (conn->child_dev == NULL) {
> /* Does it match this newly added device? */
> - if (conn->child_fwnode == csdev->dev.fwnode)
> - conn->child_dev = csdev;
> - else
> + if (conn->child_fwnode == csdev->dev.fwnode) {
> + ret = coresight_make_links(i_csdev,
> + conn, csdev);
> + if (ret)
> + return ret;
> + } else {
> /* This component still has an orphan */
> still_orphan = true;
> + }
> }
> }
>
> i_csdev->orphan = still_orphan;
>
> /*
> - * Returning '0' ensures that all known component on the
> - * bus will be checked.
> + * Returning '0' in case we didn't encounter any error,
> + * ensures that all known component on the bus will be checked.
> */
> return 0;
> }
> @@ -1082,15 +1086,21 @@ static int coresight_fixup_orphan_conns(struct coresight_device *csdev)
>
> static int coresight_fixup_device_conns(struct coresight_device *csdev)
> {
> - int i;
> + int i, ret = 0;
>
> for (i = 0; i < csdev->pdata->nr_outport; i++) {
> struct coresight_connection *conn = &csdev->pdata->conns[i];
>
> conn->child_dev =
> coresight_find_csdev_by_fwnode(conn->child_fwnode);
> - if (!conn->child_dev)
> + if (conn->child_dev) {
> + ret = coresight_make_links(csdev, conn,
> + conn->child_dev);
> + if (ret)
> + break;
> + } else {
> csdev->orphan = true;
> + }
> }
>
> return 0;
> @@ -1121,7 +1131,7 @@ static int coresight_remove_match(struct device *dev, void *data)
>
> if (csdev->dev.fwnode == conn->child_fwnode) {
> iterator->orphan = true;
> - conn->child_dev = NULL;
> + coresight_remove_links(iterator, conn);
> /*
> * Drop the reference to the handle for the remote
> * device acquired in parsing the connections from
> @@ -1215,13 +1225,23 @@ void coresight_release_platform_data(struct coresight_device *csdev,
> struct coresight_platform_data *pdata)
> {
> int i;
> + struct coresight_connection *conns = pdata->conns;
>
> for (i = 0; i < pdata->nr_outport; i++) {
> - if (pdata->conns[i].child_fwnode) {
> - fwnode_handle_put(pdata->conns[i].child_fwnode);
> + /* If we have made the links, remove them now */
> + if (csdev && conns[i].child_dev)
> + coresight_remove_links(csdev, &conns[i]);
> + /*
> + * Drop the refcount and clear the handle as this device
> + * is going away
> + */
> + if (conns[i].child_fwnode) {
> + fwnode_handle_put(conns[i].child_fwnode);
> pdata->conns[i].child_fwnode = NULL;
> }
> }
> + if (csdev)
> + coresight_remove_conns_sysfs_group(csdev);
> }
>
> struct coresight_device *coresight_register(struct coresight_desc *desc)
> @@ -1303,7 +1323,9 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
>
> mutex_lock(&coresight_mutex);
>
> - ret = coresight_fixup_device_conns(csdev);
> + ret = coresight_create_conns_sysfs_group(csdev);
> + if (!ret)
> + ret = coresight_fixup_device_conns(csdev);
> if (!ret)
> ret = coresight_fixup_orphan_conns(csdev);
> if (!ret)
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index a2ec25e02ca9..ccd17304d7bd 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -140,12 +140,14 @@ struct coresight_desc {
> * @chid_fwnode: remote component's fwnode handle.
> * @child_dev: a @coresight_device representation of the component
> connected to @outport.
> + * @link: Representation of the connection as a sysfs link.
> */
> struct coresight_connection {
> int outport;
> int child_port;
> struct fwnode_handle *child_fwnode;
> struct coresight_device *child_dev;
> + struct coresight_sysfs_link *link;
> };
>
> /**
> --
> 2.17.1
>
