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Message-ID: <5f0a3b47-4dd5-8afb-796e-ddde70bbbdbc@arm.com> Date: Thu, 16 Mar 2023 20:23:28 +0000 From: Suzuki K Poulose <suzuki.poulose@....com> To: James Clark <james.clark@....com>, coresight@...ts.linaro.org Cc: Mathieu Poirier <mathieu.poirier@...aro.org>, Mike Leach <mike.leach@...aro.org>, Leo Yan <leo.yan@...aro.org>, Alexander Shishkin <alexander.shishkin@...ux.intel.com>, linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v2 6/9] coresight: Store in-connections as well as out-connections On 10/03/2023 16:06, James Clark wrote: > This will allow CATU to get its associated ETR in a generic way where > currently the enable path has some hard coded searches which avoid > the need to store input connections. > > Signed-off-by: James Clark <james.clark@....com> > --- > drivers/hwtracing/coresight/coresight-core.c | 56 +++++++++++++++-- > .../hwtracing/coresight/coresight-platform.c | 61 ++++++++++++++++--- > drivers/hwtracing/coresight/coresight-sysfs.c | 1 - > include/linux/coresight.h | 25 ++++++++ > 4 files changed, 130 insertions(+), 13 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c > index f457914e445e..a8ba7493c09a 100644 > --- a/drivers/hwtracing/coresight/coresight-core.c > +++ b/drivers/hwtracing/coresight/coresight-core.c > @@ -59,6 +59,7 @@ const u32 coresight_barrier_pkt[4] = {0x7fffffff, 0x7fffffff, 0x7fffffff, 0x7fff > EXPORT_SYMBOL_GPL(coresight_barrier_pkt); > > static const struct cti_assoc_op *cti_assoc_ops; > +static int coresight_fixup_inputs(struct coresight_device *csdev); > > ssize_t coresight_simple_show_pair(struct device *_dev, > struct device_attribute *attr, char *buf) > @@ -1369,6 +1370,35 @@ static int coresight_fixup_orphan_conns(struct coresight_device *csdev) > csdev, coresight_orphan_match); > } > > +/* > + * Device connections are discovered before one/both devices have been created, > + * so inputs must be added later. > + */ > +static int coresight_fixup_inputs(struct coresight_device *csdev) > +{ > + int i, ret = 0; > + struct coresight_connection *out_conn; > + struct coresight_connection in_conn; > + > + for (i = 0; i < csdev->pdata->nr_outconns; i++) { > + out_conn = &csdev->pdata->out_conns[i]; > + if (!out_conn->remote_dev || !out_conn->remote_dev->pdata) > + continue; > + > + /* Reverse local/remote relationships for inputs */ > + in_conn.remote_dev = csdev; > + in_conn.remote_port = out_conn->port; > + in_conn.port = out_conn->remote_port; > + in_conn.remote_fwnode = csdev->dev.fwnode; > + ret = coresight_add_in_conn(out_conn->remote_dev->dev.parent, > + out_conn->remote_dev->pdata, > + &in_conn); > + if (ret) > + return ret; > + } > + > + return 0; > +} > > static int coresight_fixup_device_conns(struct coresight_device *csdev) > { > @@ -1427,11 +1457,20 @@ static int coresight_remove_match(struct device *dev, void *data) Removing the connection should be much simpler now with the inports connection tracking. i.e., coresight_remove_conns() need not iterate over all the devices on the coresight bus. We had to do that to find all the devices connecting to the removed device. Instead with the in_conns we could readily get the csdev instance and remove the connection from those devices. Similarly for the out_conns can give you the remove device for removing the in_conns on that device. i.e, static void coresight_remove_conns(csdev) { struct coresight_device *remote; for (i = 0; i < csdev->pdata->nr_outconns; i++) { remote = csdev->data->out_conns[i].remote_dev; if (!remote) continue; for (j = 0; j < remote->pdata->nr_inconns; j++) { if (remote->pdata->in_conns[i].remote_dev == csdev) /* Clear in_conns[i] on remote */ } } Similarly for in_conns for (i = 0; i < csdev->pdata->nr_inconns; i++) { remote = csdev->data->in_conns[i].remote_dev; if (!remote) continue; for (j = 0; j < remote->pdata->nr_outconns; j++) { if (remote->pdata->out_conns[i].remote_dev == csdev) /* Clear out_conns[i] on remote */ } > */ > fwnode_handle_put(conn->remote_fwnode); > conn->remote_fwnode = NULL; > + conn->remote_dev = NULL; > + /* No need to continue */ > + break; > + } > + } > + for (i = 0; i < iterator->pdata->nr_inconns; i++) { > + conn = &iterator->pdata->in_conns[i]; > + if (csdev == conn->remote_dev) { > + conn->remote_fwnode = NULL; > + conn->remote_dev = NULL; > /* No need to continue */ > break; > } > } > - > /* > * Returning '0' ensures that all known component on the > * bus will be checked. > @@ -1552,21 +1591,28 @@ void coresight_release_platform_data(struct coresight_device *csdev, > > for (i = 0; i < pdata->nr_outconns; i++) { > /* If we have made the links, remove them now */ > - if (csdev && conns[i].remote_dev) > + if (csdev && conns[i].remote_dev) { > coresight_remove_links(csdev, &conns[i]); > + conns[i].remote_dev = NULL; > + } > + > /* > * Drop the refcount and clear the handle as this device > * is going away > */ > if (conns[i].remote_fwnode) { > fwnode_handle_put(conns[i].remote_fwnode); > - pdata->out_conns[i].remote_fwnode = NULL; > + conns[i].remote_fwnode = NULL; > } > } > + for (i = 0; i < pdata->nr_inconns; i++) { > + pdata->in_conns[i].remote_dev = NULL; > + pdata->in_conns[i].remote_fwnode = NULL; > + } > + > if (csdev) > coresight_remove_conns_sysfs_group(csdev); > } > - > struct coresight_device *coresight_register(struct coresight_desc *desc) > { > int ret; > @@ -1659,6 +1705,8 @@ struct coresight_device *coresight_register(struct coresight_desc *desc) > ret = coresight_create_conns_sysfs_group(csdev); > if (!ret) > ret = coresight_fixup_device_conns(csdev); > + if (!ret) > + ret = coresight_fixup_inputs(csdev); Don't we also need to fixup the "input" connections on this device ? It would be good move all of this connection stuff into a wrapper function. > if (!ret) > ret = coresight_fixup_orphan_conns(csdev); > > diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c > index 16553f7dde12..20e3351cbdc2 100644 > --- a/drivers/hwtracing/coresight/coresight-platform.c > +++ b/drivers/hwtracing/coresight/coresight-platform.c > @@ -20,8 +20,7 @@ > > #include "coresight-priv.h" > /* > - * coresight_alloc_conns: Allocate connections record for each output > - * port from the device. > + * coresight_alloc_conns: Allocate connections record for each input/output device. > */ > static int coresight_alloc_conns(struct device *dev, > struct coresight_platform_data *pdata) > @@ -33,7 +32,14 @@ static int coresight_alloc_conns(struct device *dev, > if (!pdata->out_conns) > return -ENOMEM; > } > - > + if (pdata->nr_inconns) { > + pdata->in_conns = devm_krealloc_array(dev, pdata->in_conns, > + pdata->nr_inconns, > + sizeof(*pdata->in_conns), > + GFP_KERNEL | __GFP_ZERO); > + if (!pdata->in_conns) > + return -ENOMEM; > + } devm_krealloc_array() skips any allocation if the requested new_size <= origin_size. So this should be fine for the out_conns, to not realloc the space again unnecessarily. > return 0; > } > > @@ -79,6 +85,45 @@ int coresight_add_conn(struct device *dev, > } > EXPORT_SYMBOL_GPL(coresight_add_conn); Should this be named as add_out_conn in the previous patch just to make it explicit and easier to read. > > +/* > + * Add a connection in the first free slot, or realloc > + * if there is no space. > + * > + * Do nothing if the connection already exists because inputs are > + * fixed up multiple times. > + */ > +int coresight_add_in_conn(struct device *dev, > + struct coresight_platform_data *pdata, minor nit: Is there any reason why this can't simply be: int coresight_add_in_conn(struct coresight_device *csdev, struct coresight_connection *conn) { struct device *dev = csdev->dev.parent; struct coresight_platform_data *pdata = csdev->pdata; > + struct coresight_connection *conn) Suzuki > +{ > + int ret; > + struct coresight_connection *free_conn = NULL; > + int i; > + > + /* Search for a free slot or exit if a duplicate is found */ > + if (pdata->in_conns) { > + for (i = 0; i < pdata->nr_inconns; ++i) { > + if (!free_conn && !pdata->in_conns[i].remote_fwnode) > + free_conn = &pdata->in_conns[i]; > + if (pdata->in_conns[i].remote_fwnode == > + conn->remote_fwnode) > + return 0; > + } > + } > + > + if (!free_conn) { > + pdata->nr_inconns++; > + ret = coresight_alloc_conns(dev, pdata); > + if (ret) > + return ret; > + free_conn = &pdata->in_conns[pdata->nr_inconns - 1]; > + } > + > + *free_conn = *conn; > + return 0; > +} > +EXPORT_SYMBOL_GPL(coresight_add_in_conn); > + > static struct device * > coresight_find_device_by_fwnode(struct fwnode_handle *fwnode) > { > @@ -249,7 +294,7 @@ static int of_coresight_get_cpu(struct device *dev) > > /* > * of_coresight_parse_endpoint : Parse the given output endpoint @ep > - * and fill the connection information in @conn > + * and fill the connection information in @in_conn and @out_conn > * > * Parses the local port, remote device name and the remote port. > * > @@ -333,14 +378,14 @@ static int of_get_coresight_platform_data(struct device *dev, > /* Get the number of input and output port for this component */ > of_coresight_get_ports(node, &pdata->nr_inconns, &pdata->nr_outconns); > > - /* If there are no output connections, we are done */ > - if (!pdata->nr_outconns) > - return 0; > - > ret = coresight_alloc_conns(dev, pdata); > if (ret) > return ret; > > + /* If there are no output connections, we are done */ > + if (!pdata->nr_outconns) > + return 0; > + > parent = of_coresight_get_output_ports_node(node); > /* > * If the DT uses obsoleted bindings, the ports are listed > diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c > index 3da9868d9237..2abf9639ac0f 100644 > --- a/drivers/hwtracing/coresight/coresight-sysfs.c > +++ b/drivers/hwtracing/coresight/coresight-sysfs.c > @@ -202,5 +202,4 @@ void coresight_remove_links(struct coresight_device *orig, > devm_kfree(&orig->dev, conn->link->orig_name); > devm_kfree(&orig->dev, conn->link); > conn->link = NULL; > - conn->remote_dev = NULL; > } > diff --git a/include/linux/coresight.h b/include/linux/coresight.h > index 47fa58d6981d..fd268b24c761 100644 > --- a/include/linux/coresight.h > +++ b/include/linux/coresight.h > @@ -110,6 +110,7 @@ struct coresight_platform_data { > int nr_inconns; > int nr_outconns; > struct coresight_connection *out_conns; > + struct coresight_connection *in_conns; Please document the field above the structure. Suzuki > }; > > /** > @@ -177,6 +178,27 @@ struct coresight_desc { > * @remote_fwnode once the remote's coresight_device has > * been created. > * @link: Representation of the connection as a sysfs link. > + * > + * The full connection structure looks like this, where in_conns store references to > + * the parent device in the same remote_dev member as output connections. > + * > + * +-----------------------------+ +-----------------------------+ > + * |coresight_device | |coresight_connection | > + * |-----------------------------| |-----------------------------| > + * ---->| | | | > + * | | | | remote_dev*|------ > + * | |pdata->out_conns[nr_outconns]|----------->| | | > + * | | | | | | > + * | +-----------------------------+ +-----------------------------+ | > + * | | > + * | +-----------------------------+ +-----------------------------+ | > + * | |coresight_connection | |coresight_device | | > + * | |-----------------------------| |------------------------------ | > + * | | | | |<----- > + * -----|remote_dev* | | | > + * | |<-----------|pdata->in_conns[nr_inconns] | > + * | | | | > + * +-----------------------------+ +-----------------------------+ > */ > struct coresight_connection { > int port; > @@ -619,5 +641,8 @@ struct coresight_platform_data *coresight_get_platform_data(struct device *dev); > int coresight_add_conn(struct device *dev, > struct coresight_platform_data *pdata, > const struct coresight_connection *conn); > +int coresight_add_in_conn(struct device *dev, > + struct coresight_platform_data *pdata, > + struct coresight_connection *conn); > > #endif /* _LINUX_COREISGHT_H */
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