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[68.147.8.254]) by smtp.gmail.com with ESMTPSA id w8sm3940680pfn.186.2020.02.26.13.23.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 26 Feb 2020 13:23:05 -0800 (PST) Date: Wed, 26 Feb 2020 14:23:04 -0700 From: Mathieu Poirier To: Mike Leach Cc: linux-arm-kernel , Coresight ML , "open list:DOCUMENTATION" , "Suzuki K. Poulose" Subject: Re: [PATCH v4 4/6] coresight: Expose device connections via sysfs Message-ID: <20200226212304.GC30754@xps15> References: <20200211105808.27884-1-mike.leach@linaro.org> <20200211105808.27884-5-mike.leach@linaro.org> <20200214223111.GA20024@xps15> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Wed, Feb 26, 2020 at 02:32:16PM +0000, Mike Leach wrote: > Hi Mathieu, > > On Fri, 14 Feb 2020 at 22:31, Mathieu Poirier > wrote: > > > > Hi Mike, > > > > On Tue, Feb 11, 2020 at 10:58:06AM +0000, Mike Leach wrote: > > > From: Suzuki K Poulose > > > > > > 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 > > > Signed-off-by: Suzuki K Poulose > > > > > > Revised to use the generic sysfs links functions & link structures. > > > Provides a connections sysfs group to hold the links. > > > > > > Co-developed-by: Mike Leach > > > Signed-off-by: Mike Leach > > > > Because this patch is "From:" Suzuki, this should be: > > > > Co-developed-by: Suzuki K Poulose > > Signed-off-by: Mike Leach > > > > if I do the above then checkpatch.pl:- > > WARNING: Co-developed-by: should not be used to attribute nominal > patch author 'Suzuki K Poulose ' > #25: > Co-developed-by: Suzuki K Poulose > WARNING: Co-developed-by and Signed-off-by: name/email do not match > #25: > Co-developed-by: Suzuki K Poulose > Signed-off-by: Mike Leach Got that - thanks > > Regards > > Mike > > > 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 > > > > > --- > > > 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 > > > > > > > -- > Mike Leach > Principal Engineer, ARM Ltd. > Manchester Design Centre. UK