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@linaro.org --- drivers/hwtracing/coresight/Makefile | 3 +- drivers/hwtracing/coresight/coresight-priv.h | 4 + drivers/hwtracing/coresight/coresight-sysfs.c | 123 ++++++++++++++++++ include/linux/coresight.h | 20 +++ 4 files changed, 149 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 1065fa3bce7d..41660203a603 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..667c5d07551a --- /dev/null +++ b/drivers/hwtracing/coresight/coresight-sysfs.c @@ -0,0 +1,123 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019, The Linux Foundation. All rights reserved. + */ + +#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; + 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 b5dc9baf0c58..816baee37bf6 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; };

/*

From: Suzuki K Poulose suzuki.poulose@arm.com

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

Provides default connections group if requested for any CoreSight device using the coresight_connections structure.

If a connections group is present on a device then links are collated there.

Co-developed-by: Mike Leach mike.leach@linaro.org Signed-off-by: Mike Leach mike.leach@linaro.org Cc: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com --- drivers/hwtracing/coresight/coresight-priv.h | 5 ++ drivers/hwtracing/coresight/coresight-sysfs.c | 80 +++++++++++++++++++ drivers/hwtracing/coresight/coresight.c | 43 +++++++--- include/linux/coresight.h | 2 + 4 files changed, 118 insertions(+), 12 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index 41660203a603..e9273cc318bd 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 667c5d07551a..bc1f71ef560e 100644 --- a/drivers/hwtracing/coresight/coresight-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-sysfs.c @@ -121,3 +121,83 @@ 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 0e8d1f2a9ff6..63b8ed106d4a 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -1016,7 +1016,7 @@ 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; @@ -1041,19 +1041,23 @@ 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; } @@ -1067,7 +1071,7 @@ 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]; @@ -1075,9 +1079,12 @@ static int coresight_fixup_device_conns(struct coresight_device *csdev)

dev = bus_find_device_by_fwnode(&coresight_bustype, conn->child_fwnode); if (dev) { - conn->child_dev = to_coresight_device(dev); + ret = coresight_make_links(csdev, conn, + to_coresight_device(dev)); /* and put reference from 'bus_find_device()' */ put_device(dev); + if (ret) + break; } else { csdev->orphan = true; conn->child_dev = NULL; @@ -1112,7 +1119,7 @@ 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 @@ -1206,13 +1213,23 @@ 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) @@ -1294,7 +1311,9 @@ 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 816baee37bf6..1d5e1de2014a 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; };

/**

Adds in sysfs links for connections where the connected device is another coresight device. This allows examination of the coresight topology.

Non-coresight connections remain just as a reference name.

Signed-off-by: Mike Leach mike.leach@linaro.org --- drivers/hwtracing/coresight/coresight-cti.c | 44 +++++++++++++++++++-- 1 file changed, 41 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c index c3d63cc53bdd..b6422ae7c233 100644 --- a/drivers/hwtracing/coresight/coresight-cti.c +++ b/drivers/hwtracing/coresight/coresight-cti.c @@ -440,6 +440,37 @@ int cti_channel_setop(struct device *dev, enum cti_chan_set_op op, return err; }

+static void cti_add_sysfs_link(struct cti_drvdata *drvdata, + struct cti_trig_con *tc) +{ + struct coresight_sysfs_link link_info; + + link_info.orig = drvdata->csdev; + link_info.orig_name = tc->con_dev_name; + link_info.target = tc->con_dev; + link_info.target_name = dev_name(&drvdata->csdev->dev); + coresight_add_sysfs_link(&link_info); +} + +static void cti_remove_all_sysfs_links(struct cti_drvdata *drvdata) +{ + struct cti_trig_con *tc; + struct cti_device *ctidev = &drvdata->ctidev; + struct coresight_sysfs_link link_info; + + /* origin device and target link name constant for this cti */ + link_info.orig = drvdata->csdev; + link_info.target_name = dev_name(&drvdata->csdev->dev); + + list_for_each_entry(tc, &ctidev->trig_cons, node) { + if (tc->con_dev) { + link_info.target = tc->con_dev; + link_info.orig_name = tc->con_dev_name; + coresight_remove_sysfs_link(&link_info); + } + } +} + /* * Look for a matching connection device name in the list of * connections. If found then swap in the csdev name and return @@ -447,7 +478,7 @@ int cti_channel_setop(struct device *dev, enum cti_chan_set_op op, */ static bool cti_match_con_name(struct cti_device *ctidev, const char *node_name, - const char *csdev_name) + const char *csdev_name, struct cti_trig_con **tc) { struct cti_trig_con *trig_con;

@@ -458,6 +489,7 @@ cti_match_con_name(struct cti_device *ctidev, const char *node_name, kfree(trig_con->con_dev_name); trig_con->con_dev_name = kstrdup(csdev_name, GFP_KERNEL); + *tc = trig_con; return true; } } @@ -474,6 +506,7 @@ void cti_add_assoc_to_csdev(struct coresight_device *csdev) struct cti_drvdata *ect_item; struct cti_device *ctidev; const char *node_name = NULL, *csdev_name; + struct cti_trig_con *tc = NULL;

/* protect the list */ mutex_lock(&ect_mutex); @@ -494,12 +527,14 @@ void cti_add_assoc_to_csdev(struct coresight_device *csdev) /* for each CTI in list... */ list_for_each_entry(ect_item, &ect_net, node) { ctidev = &ect_item->ctidev; - if (cti_match_con_name(ctidev, node_name, csdev_name)) { + if (cti_match_con_name(ctidev, node_name, csdev_name, &tc)) { /* * if we found a matching name then update the * association pointers. */ csdev->ect_dev = ect_item->csdev; + tc->con_dev = csdev; + cti_add_sysfs_link(ect_item, tc); goto cti_add_done; } } @@ -519,8 +554,10 @@ static void cti_update_conn_xrefs(struct cti_drvdata *drvdata) struct cti_device *ctidev = &drvdata->ctidev;

list_for_each_entry(tc, &ctidev->trig_cons, node) { - if (tc->con_dev) + if (tc->con_dev) { tc->con_dev->ect_dev = drvdata->csdev; + cti_add_sysfs_link(drvdata, tc); + } } }

@@ -562,6 +599,7 @@ static void cti_device_release(struct device *dev) mutex_lock(&ect_mutex);

/* clear the dynamic sysfs associate with connections */ + cti_remove_all_sysfs_links(drvdata); cti_destroy_cons_sysfs(&drvdata->ctidev);

/* remove from the list */