The connections between CoreSight sources, links and sinks is not obvious without documentation or access to the device tree / ACPI definitions for the platform.
This patchset provides sysfs links to enable the user to follow the trace patch from source to sink.
Components in the trace path are updated to have a connections sysfs group, which collates all the links for that component.
The CTI components which exist aside from the main trace patch, also have an added connections directory showing connections to other CoreSight devices.
This patchset applies on top of the recent CTI v10 patchset [1].
Adaptation of an original patchset [2] from Suzuki, reusing 2 patches unchanged with update to 3rd adapt to the new common code for trace path and CTI component links & add a default connections group.
Tested on Juno r1, DB410c; kernel 5.6-rc3
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2020-February/714140.h... [2] https://lists.linaro.org/pipermail/coresight/2019-May/002803.html
Changes since v4: 1) Rebased for v10 CTI set[1]. 2) Code for adding in the CTI->[other CoreSight] links revised to ensure consistent create / release process. Warn on highly unlikely event that link cannot be made & remove any programmatic association between the components.
Changes since v3: 1) Rebased onto 5.6-rc1 kernel with CTI set[1].
Changes since v2: 1) Fixed issues with signature ordering noted by Suzuki. 2) Alterations to main CTI set[1] to overcome issue noted by Matthieu.
Changes since v1: 1) Code from original v4 CTI set moved here so that all connections related code in this set. 2) Connections directory mandatory for all CoreSight components and generated as part of the registration process. Mike Leach (3): coresight: Add generic sysfs link creation functions coresight: cti: Add in sysfs links to other coresight devices coresight: docs: Add information about the topology representations
Suzuki K Poulose (3): coresight: Pass coresight_device for coresight_release_platform_data coresight: add return value for fixup connections coresight: Expose device connections via sysfs
.../trace/coresight/coresight-ect.rst | 5 +- Documentation/trace/coresight/coresight.rst | 85 ++++++++ drivers/hwtracing/coresight/Makefile | 3 +- drivers/hwtracing/coresight/coresight-cti.c | 52 ++++- .../hwtracing/coresight/coresight-platform.c | 2 +- drivers/hwtracing/coresight/coresight-priv.h | 12 +- drivers/hwtracing/coresight/coresight-sysfs.c | 204 ++++++++++++++++++ drivers/hwtracing/coresight/coresight.c | 75 ++++--- include/linux/coresight.h | 22 ++ 9 files changed, 428 insertions(+), 32 deletions(-) create mode 100644 drivers/hwtracing/coresight/coresight-sysfs.c
From: Suzuki K Poulose suzuki.poulose@arm.com
As we prepare to expose the links between the devices in sysfs, pass the coresight_device instance to the coresight_release_platform_data in order to free up the connections when the device is removed.
No functional changes as such in this patch.
Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: Mike Leach mike.leach@linaro.org --- drivers/hwtracing/coresight/coresight-platform.c | 2 +- drivers/hwtracing/coresight/coresight-priv.h | 3 ++- drivers/hwtracing/coresight/coresight.c | 7 ++++--- 3 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c index 43418a2126ff..4b78e1ac5285 100644 --- a/drivers/hwtracing/coresight/coresight-platform.c +++ b/drivers/hwtracing/coresight/coresight-platform.c @@ -822,7 +822,7 @@ coresight_get_platform_data(struct device *dev) error: if (!IS_ERR_OR_NULL(pdata)) /* Cleanup the connection information */ - coresight_release_platform_data(pdata); + coresight_release_platform_data(NULL, pdata); return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(coresight_get_platform_data); diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h index 890f9a5c97c6..1cad642f27aa 100644 --- a/drivers/hwtracing/coresight/coresight-priv.h +++ b/drivers/hwtracing/coresight/coresight-priv.h @@ -211,7 +211,8 @@ static inline void *coresight_get_uci_data(const struct amba_id *id) return 0; }
-void coresight_release_platform_data(struct coresight_platform_data *pdata); +void coresight_release_platform_data(struct coresight_device *csdev, + struct coresight_platform_data *pdata); struct coresight_device * coresight_find_csdev_by_fwnode(struct fwnode_handle *r_fwnode); void coresight_set_assoc_ectdev_mutex(struct coresight_device *csdev, diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index c71553c09f8e..10e756410d3c 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -1213,7 +1213,8 @@ postcore_initcall(coresight_init); * coresight_release_platform_data: Release references to the devices connected * to the output port of this device. */ -void coresight_release_platform_data(struct coresight_platform_data *pdata) +void coresight_release_platform_data(struct coresight_device *csdev, + struct coresight_platform_data *pdata) { int i;
@@ -1316,7 +1317,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) kfree(csdev); err_out: /* Cleanup the connection information */ - coresight_release_platform_data(desc->pdata); + coresight_release_platform_data(NULL, desc->pdata); return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(coresight_register); @@ -1326,7 +1327,7 @@ void coresight_unregister(struct coresight_device *csdev) etm_perf_del_symlink_sink(csdev); /* Remove references of that device in the topology */ coresight_remove_conns(csdev); - coresight_release_platform_data(csdev->pdata); + coresight_release_platform_data(csdev, csdev->pdata); device_unregister(&csdev->dev); } EXPORT_SYMBOL_GPL(coresight_unregister);
From: Suzuki K Poulose suzuki.poulose@arm.com
Handle failures in fixing up connections for a newly registered device. This will be useful to handle cases where we fail to expose the links via sysfs for the connections.
Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: Mike Leach mike.leach@linaro.org --- drivers/hwtracing/coresight/coresight.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 10e756410d3c..07f66a3968f1 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -1073,18 +1073,14 @@ static int coresight_orphan_match(struct device *dev, void *data) return 0; }
-static void coresight_fixup_orphan_conns(struct coresight_device *csdev) +static int coresight_fixup_orphan_conns(struct coresight_device *csdev) { - /* - * No need to check for a return value as orphan connection(s) - * are hooked-up with each newly added component. - */ - bus_for_each_dev(&coresight_bustype, NULL, + return bus_for_each_dev(&coresight_bustype, NULL, csdev, coresight_orphan_match); }
-static void coresight_fixup_device_conns(struct coresight_device *csdev) +static int coresight_fixup_device_conns(struct coresight_device *csdev) { int i;
@@ -1096,6 +1092,8 @@ static void coresight_fixup_device_conns(struct coresight_device *csdev) if (!conn->child_dev) csdev->orphan = true; } + + return 0; }
static int coresight_remove_match(struct device *dev, void *data) @@ -1305,11 +1303,17 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
mutex_lock(&coresight_mutex);
- coresight_fixup_device_conns(csdev); - coresight_fixup_orphan_conns(csdev); - cti_add_assoc_to_csdev(csdev); + ret = coresight_fixup_device_conns(csdev); + if (!ret) + ret = coresight_fixup_orphan_conns(csdev); + if (!ret) + cti_add_assoc_to_csdev(csdev);
mutex_unlock(&coresight_mutex); + if (ret) { + coresight_unregister(csdev); + return ERR_PTR(ret); + }
return csdev;
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 Reviewed-by: Suzuki K Poulose suzuki.poulose@arm.com Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org --- 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@linaro.org + */ + +#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 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; };
/*
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
Cc: Mathieu Poirier mathieu.poirier@linaro.org Signed-off-by: Suzuki K Poulose suzuki.poulose@arm.com
Revised to use the generic sysfs links functions & link structures. Provides a connections sysfs group in each device to hold the links.
Co-developed-by: Mike Leach mike.leach@linaro.org Signed-off-by: Mike Leach mike.leach@linaro.org Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org --- drivers/hwtracing/coresight/coresight-priv.h | 5 ++ drivers/hwtracing/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; };
/**
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 | 52 +++++++++++++++++++-- 1 file changed, 48 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c index aa6e0249bd70..9e262f5a85e3 100644 --- a/drivers/hwtracing/coresight/coresight-cti.c +++ b/drivers/hwtracing/coresight/coresight-cti.c @@ -442,6 +442,34 @@ int cti_channel_setop(struct device *dev, enum cti_chan_set_op op, return err; }
+static bool cti_add_sysfs_link(struct cti_drvdata *drvdata, + struct cti_trig_con *tc) +{ + struct coresight_sysfs_link link_info; + int link_err = 0; + + 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); + + link_err = coresight_add_sysfs_link(&link_info); + if (link_err) + dev_warn(&drvdata->csdev->dev, + "Failed to set CTI sysfs link %s<=>%s\n", + link_info.orig_name, link_info.target_name); + return !link_err; +} + +static void cti_remove_sysfs_link(struct cti_trig_con *tc) +{ + struct coresight_sysfs_link link_info; + + link_info.orig_name = tc->con_dev_name; + link_info.target = tc->con_dev; + 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, set trig con association pointer @@ -452,6 +480,8 @@ cti_match_fixup_csdev(struct cti_device *ctidev, const char *node_name, struct coresight_device *csdev) { struct cti_trig_con *tc; + struct cti_drvdata *drvdata = container_of(ctidev, struct cti_drvdata, + ctidev);
list_for_each_entry(tc, &ctidev->trig_cons, node) { if (tc->con_dev_name) { @@ -459,7 +489,12 @@ cti_match_fixup_csdev(struct cti_device *ctidev, const char *node_name, /* match: so swap in csdev name & dev */ tc->con_dev_name = dev_name(&csdev->dev); tc->con_dev = csdev; - return true; + /* try to set sysfs link */ + if (cti_add_sysfs_link(drvdata, tc)) + return true; + /* link failed - remove CTI reference */ + tc->con_dev = NULL; + break; } } } @@ -522,6 +557,7 @@ void cti_remove_assoc_from_csdev(struct coresight_device *csdev) ctidev = &ctidrv->ctidev; list_for_each_entry(tc, &ctidev->trig_cons, node) { if (tc->con_dev == csdev->ect_dev) { + cti_remove_sysfs_link(tc); tc->con_dev = NULL; break; } @@ -543,10 +579,16 @@ 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) - /* set tc->con_dev->ect_dev */ - coresight_set_assoc_ectdev_mutex(tc->con_dev, + if (tc->con_dev) { + /* if we can set the sysfs link */ + if (cti_add_sysfs_link(drvdata, tc)) + /* set the CTI/csdev association */ + coresight_set_assoc_ectdev_mutex(tc->con_dev, drvdata->csdev); + else + /* otherwise remove reference from CTI */ + tc->con_dev = NULL; + } } }
@@ -559,6 +601,8 @@ static void cti_remove_conn_xrefs(struct cti_drvdata *drvdata) if (tc->con_dev) { coresight_set_assoc_ectdev_mutex(tc->con_dev, NULL); + cti_remove_sysfs_link(tc); + tc->con_dev = NULL; } } }
Update the CoreSight documents to describe the new connections directory and the links between CoreSight devices in this directory.
Signed-off-by: Mike Leach mike.leach@linaro.org Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org --- .../trace/coresight/coresight-ect.rst | 5 +- Documentation/trace/coresight/coresight.rst | 85 +++++++++++++++++++ 2 files changed, 89 insertions(+), 1 deletion(-)
diff --git a/Documentation/trace/coresight/coresight-ect.rst b/Documentation/trace/coresight/coresight-ect.rst index 067cee91c857..3539af895832 100644 --- a/Documentation/trace/coresight/coresight-ect.rst +++ b/Documentation/trace/coresight/coresight-ect.rst @@ -71,7 +71,7 @@ capable of generating or using trigger signals.::
$ ls /sys/bus/coresight/devices/etm0/cti_cpu0
channels ctmid enable nr_trigger_cons mgmt power regs subsystem - triggers0 triggers1 uevent + connections triggers0 triggers1 uevent
*Key file items are:-* * ``enable``: enables/disables the CTI. @@ -84,6 +84,9 @@ capable of generating or using trigger signals.:: * ``channels``: Contains the channel API - CTI main programming interface. * ``regs``: Gives access to the raw programmable CTI regs. * ``mgmt``: the standard CoreSight management registers. + * ``connections``: Links to connected *CoreSight* devices. The number of + links can be 0 to ``nr_trigger_cons``. Actual number given by ``nr_links`` + in this directory.
triggers<N> directories diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst index 108600ee1e12..0b73acb44efa 100644 --- a/Documentation/trace/coresight/coresight.rst +++ b/Documentation/trace/coresight/coresight.rst @@ -241,6 +241,91 @@ to the newer scheme, to give a confirmation that what you see on your system is not unexpected. One must use the "names" as they appear on the system under specified locations.
+Topology Representation +----------------------- + +Each CoreSight component has a ``connections`` directory which will contain +links to other CoreSight components. This allows the user to explore the trace +topology and for larger systems, determine the most appropriate sink for a +given source. The connection information can also be used to establish +which CTI devices are connected to a given component. This directory contains a +``nr_links`` attribute detailing the number of links in the directory. + +For an ETM source, in this case ``etm0`` on a Juno platform, a typical +arrangement will be:: + + linaro-developer:~# ls - l /sys/bus/coresight/devices/etm0/connections + <file details> cti_cpu0 -> ../../../23020000.cti/cti_cpu0 + <file details> nr_links + <file details> out:0 -> ../../../230c0000.funnel/funnel2 + +Following the out port to ``funnel2``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/funnel2/connections + <file details> in:0 -> ../../../23040000.etm/etm0 + <file details> in:1 -> ../../../23140000.etm/etm3 + <file details> in:2 -> ../../../23240000.etm/etm4 + <file details> in:3 -> ../../../23340000.etm/etm5 + <file details> nr_links + <file details> out:0 -> ../../../20040000.funnel/funnel0 + +And again to ``funnel0``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/funnel0/connections + <file details> in:0 -> ../../../220c0000.funnel/funnel1 + <file details> in:1 -> ../../../230c0000.funnel/funnel2 + <file details> nr_links + <file details> out:0 -> ../../../20010000.etf/tmc_etf0 + +Finding the first sink ``tmc_etf0``. This can be used to collect data +as a sink, or as a link to propagate further along the chain:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/tmc_etf0/connections + <file details> cti_sys0 -> ../../../20020000.cti/cti_sys0 + <file details> in:0 -> ../../../20040000.funnel/funnel0 + <file details> nr_links + <file details> out:0 -> ../../../20150000.funnel/funnel4 + +via ``funnel4``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/funnel4/connections + <file details> in:0 -> ../../../20010000.etf/tmc_etf0 + <file details> in:1 -> ../../../20140000.etf/tmc_etf1 + <file details> nr_links + <file details> out:0 -> ../../../20120000.replicator/replicator0 + +and a ``replicator0``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/replicator0/connections + <file details> in:0 -> ../../../20150000.funnel/funnel4 + <file details> nr_links + <file details> out:0 -> ../../../20030000.tpiu/tpiu0 + <file details> out:1 -> ../../../20070000.etr/tmc_etr0 + +Arriving at the final sink in the chain, ``tmc_etr0``:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/tmc_etr0/connections + <file details> cti_sys0 -> ../../../20020000.cti/cti_sys0 + <file details> in:0 -> ../../../20120000.replicator/replicator0 + <file details> nr_links + +As described below, when using sysfs it is sufficient to enable a sink and +a source for successful trace. The framework will correctly enable all +intermediate links as required. + +Note: ``cti_sys0`` appears in two of the connections lists above. +CTIs can connect to multiple devices and are arranged in a star topology +via the CTM. See (:doc:`coresight-ect`) [#fourth]_ for further details. +Looking at this device we see 4 connections:: + + linaro-developer:~# ls -l /sys/bus/coresight/devices/cti_sys0/connections + <file details> nr_links + <file details> stm0 -> ../../../20100000.stm/stm0 + <file details> tmc_etf0 -> ../../../20010000.etf/tmc_etf0 + <file details> tmc_etr0 -> ../../../20070000.etr/tmc_etr0 + <file details> tpiu0 -> ../../../20030000.tpiu/tpiu0 + + How to use the tracer modules -----------------------------
On Thu, 27 Feb 2020 at 08:14, Mike Leach mike.leach@linaro.org wrote:
The connections between CoreSight sources, links and sinks is not obvious without documentation or access to the device tree / ACPI definitions for the platform.
This patchset provides sysfs links to enable the user to follow the trace patch from source to sink.
Components in the trace path are updated to have a connections sysfs group, which collates all the links for that component.
The CTI components which exist aside from the main trace patch, also have an added connections directory showing connections to other CoreSight devices.
This patchset applies on top of the recent CTI v10 patchset [1].
Adaptation of an original patchset [2] from Suzuki, reusing 2 patches unchanged with update to 3rd adapt to the new common code for trace path and CTI component links & add a default connections group.
Tested on Juno r1, DB410c; kernel 5.6-rc3
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2020-February/714140.h... [2] https://lists.linaro.org/pipermail/coresight/2019-May/002803.html
Changes since v4:
- Rebased for v10 CTI set[1].
- Code for adding in the CTI->[other CoreSight] links revised to ensure
consistent create / release process. Warn on highly unlikely event that link cannot be made & remove any programmatic association between the components.
Changes since v3:
- Rebased onto 5.6-rc1 kernel with CTI set[1].
Changes since v2:
- Fixed issues with signature ordering noted by Suzuki.
- Alterations to main CTI set[1] to overcome issue noted by Matthieu.
Changes since v1:
- Code from original v4 CTI set moved here so that all connections related
code in this set. 2) Connections directory mandatory for all CoreSight components and generated as part of the registration process. Mike Leach (3): coresight: Add generic sysfs link creation functions coresight: cti: Add in sysfs links to other coresight devices coresight: docs: Add information about the topology representations
Suzuki K Poulose (3): coresight: Pass coresight_device for coresight_release_platform_data coresight: add return value for fixup connections coresight: Expose device connections via sysfs
.../trace/coresight/coresight-ect.rst | 5 +- Documentation/trace/coresight/coresight.rst | 85 ++++++++ drivers/hwtracing/coresight/Makefile | 3 +- drivers/hwtracing/coresight/coresight-cti.c | 52 ++++- .../hwtracing/coresight/coresight-platform.c | 2 +- drivers/hwtracing/coresight/coresight-priv.h | 12 +- drivers/hwtracing/coresight/coresight-sysfs.c | 204 ++++++++++++++++++ drivers/hwtracing/coresight/coresight.c | 75 ++++--- include/linux/coresight.h | 22 ++ 9 files changed, 428 insertions(+), 32 deletions(-) create mode 100644 drivers/hwtracing/coresight/coresight-sysfs.c
I have applied this set.
Thanks, Mathieu
-- 2.17.1
-
Mathieu Poirier -
Mike Leach