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Message-ID: <CAJ9a7VggC3Xc8=1n=rohVc1Z30sCwWbeT0wzvW0qStZhM0bK=w@mail.gmail.com>
Date: Wed, 12 Apr 2023 16:17:31 +0100
From: Mike Leach <mike.leach@...aro.org>
To: James Clark <james.clark@....com>
Cc: coresight@...ts.linaro.org, quic_jinlmao@...cinc.com,
suzuki.poulose@....com,
Mathieu Poirier <mathieu.poirier@...aro.org>,
Leo Yan <leo.yan@...aro.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 09/13] coresight: Store in-connections as well as out-connections
On Tue, 4 Apr 2023 at 16:52, James Clark <james.clark@....com> 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.
>
> This also means that the full search for connected devices on removal
> can be replaced with a loop through only the input and output devices.
>
> Signed-off-by: James Clark <james.clark@....com>
> ---
> drivers/hwtracing/coresight/coresight-core.c | 81 +++++++++----------
> .../hwtracing/coresight/coresight-platform.c | 31 ++++++-
> drivers/hwtracing/coresight/coresight-sysfs.c | 7 --
> include/linux/coresight.h | 26 ++++++
> 4 files changed, 95 insertions(+), 50 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index 8d377a59e0be..a0a0ea2c626b 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -1349,6 +1349,17 @@ static int coresight_orphan_match(struct device *dev, void *data)
> ret = coresight_make_links(src_csdev, conn, dst_csdev);
> if (ret)
> return ret;
> +
> + /*
> + * Install the device connection. This also indicates that
> + * the links are operational on both ends.
> + */
> + conn->dest_dev = dst_csdev;
> + conn->src_dev = src_csdev;
> +
> + ret = coresight_add_in_conn(conn);
> + if (ret)
> + return ret;
> } else {
> /* This component still has an orphan */
> still_orphan = true;
> @@ -1370,58 +1381,43 @@ static int coresight_fixup_orphan_conns(struct coresight_device *csdev)
> csdev, coresight_orphan_match);
> }
>
> -static int coresight_remove_match(struct device *dev, void *data)
> +/* coresight_remove_conns - Remove other device's references to this device */
> +static void coresight_remove_conns(struct coresight_device *csdev)
> {
> - int i;
> - struct coresight_device *csdev, *iterator;
> + int i, j;
> struct coresight_connection *conn;
>
> - csdev = data;
> - iterator = to_coresight_device(dev);
> -
> - /* No need to check oneself */
> - if (csdev == iterator)
> - return 0;
> -
> /*
> - * Circle throuch all the connection of that component. If we find
> - * a connection whose name matches @csdev, remove it.
> + * Remove the input connection references from the destination device
> + * for each output connection.
> */
> - for (i = 0; i < iterator->pdata->nr_outconns; i++) {
> - conn = iterator->pdata->out_conns[i];
> -
> - /* Child_dev being set signifies that the links were made */
> - if (csdev->dev.fwnode == conn->dest_fwnode && conn->dest_dev) {
> - iterator->orphan = true;
> - coresight_remove_links(iterator, conn);
> - conn->dest_dev = NULL;
> - /* No need to continue */
> - break;
> - }
> + for (i = 0; i < csdev->pdata->nr_outconns; i++) {
> + conn = csdev->pdata->out_conns[i];
> + if (!conn->dest_dev)
> + continue;
> +
> + for (j = 0; j < conn->dest_dev->pdata->nr_inconns; ++j)
> + if (conn->dest_dev->pdata->in_conns[j] == conn) {
> + conn->dest_dev->pdata->in_conns[j] = NULL;
> + break;
> + }
> }
>
> /*
> - * Returning '0' ensures that all known component on the
> - * bus will be checked.
> + * For all input connections, remove references to this device.
> + * Connection objects are shared so modifying this device's input
> + * connections affects the other device's output connection.
> */
> - return 0;
> -}
> + for (i = 0; i < csdev->pdata->nr_inconns; ++i) {
> + conn = csdev->pdata->in_conns[i];
> + /* Input conns array is sparse */
> + if (!conn)
> + continue;
>
> -/*
> - * coresight_remove_conns - Remove references to this given devices
> - * from the connections of other devices.
> - */
> -static void coresight_remove_conns(struct coresight_device *csdev)
> -{
> - /*
> - * Another device will point to this device only if there is
> - * an output port connected to this one. i.e, if the device
> - * doesn't have at least one input port, there is no point
> - * in searching all the devices.
> - */
> - if (csdev->pdata->high_inport)
> - bus_for_each_dev(&coresight_bustype, NULL,
> - csdev, coresight_remove_match);
> + conn->src_dev->orphan = true;
> + coresight_remove_links(conn->src_dev, conn);
> + conn->dest_dev = NULL;
> + }
> }
>
> /**
> @@ -1532,6 +1528,7 @@ void coresight_release_platform_data(struct coresight_device *csdev,
> devm_kfree(dev, conns[i]);
> }
> devm_kfree(dev, pdata->out_conns);
> + devm_kfree(dev, pdata->in_conns);
> devm_kfree(dev, pdata);
> if (csdev)
> coresight_remove_conns_sysfs_group(csdev);
> diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
> index 9c05f787278b..257ad48925a1 100644
> --- a/drivers/hwtracing/coresight/coresight-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-platform.c
> @@ -70,6 +70,35 @@ coresight_add_out_conn(struct device *dev,
> }
> EXPORT_SYMBOL_GPL(coresight_add_out_conn);
>
> +/*
> + * Add an input connection reference to @out_conn in the target's in_conns array
> + *
> + * @out_conn: Existing output connection to store as an input on the
> + * connection's remote device.
> + */
> +int coresight_add_in_conn(struct coresight_connection *out_conn)
> +{
> + int i;
> + struct device *dev = out_conn->dest_dev->dev.parent;
> + struct coresight_platform_data *pdata = out_conn->dest_dev->pdata;
> +
> + for (i = 0; i < pdata->nr_inconns; ++i)
> + if (!pdata->in_conns[i]) {
> + pdata->in_conns[i] = out_conn;
> + return 0;
> + }
> +
> + pdata->nr_inconns++;
> + pdata->in_conns =
> + devm_krealloc_array(dev, pdata->in_conns, pdata->nr_inconns,
> + sizeof(*pdata->in_conns), GFP_KERNEL);
> + if (!pdata->in_conns)
> + return -ENOMEM;
> + pdata->in_conns[pdata->nr_inconns - 1] = out_conn;
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(coresight_add_in_conn);
> +
> static struct device *
> coresight_find_device_by_fwnode(struct fwnode_handle *fwnode)
> {
> @@ -240,7 +269,7 @@ 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 @pdata->out_conns
> *
> * Parses the local port, remote device name and the remote port.
> *
> diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
> index a4a8e8e642e8..464ba5e1343b 100644
> --- a/drivers/hwtracing/coresight/coresight-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-sysfs.c
> @@ -173,12 +173,6 @@ int coresight_make_links(struct coresight_device *orig,
> break;
>
> conn->link = link;
> -
> - /*
> - * Install the device connection. This also indicates that
> - * the links are operational on both ends.
> - */
> - conn->dest_dev = target;
> return 0;
> } while (0);
>
> @@ -202,5 +196,4 @@ 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->dest_dev = NULL;
> }
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index abf36a37fdb0..e9c52c5ca7f3 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -106,6 +106,9 @@ union coresight_dev_subtype {
> * @nr_outconns: Number of elements for the output connections.
> * @out_conns: Array of nr_outconns pointers to connections from this
> * component.
> + * @in_conns: Sparse array of pointers to input connections. Sparse
> + * because the source device owns the connection so when it's
> + * unloaded the connection leaves an empty slot.
> */
> struct coresight_platform_data {
> int high_inport;
> @@ -113,6 +116,7 @@ struct coresight_platform_data {
> int nr_inconns;
> int nr_outconns;
> struct coresight_connection **out_conns;
> + struct coresight_connection **in_conns;
> };
>
> /**
> @@ -173,6 +177,26 @@ struct coresight_desc {
> * @dest_dev: a @coresight_device representation of the component
> connected to @src_port. NULL until the device is created
> * @link: Representation of the connection as a sysfs link.
> + *
> + * The full connection structure looks like this, where in_conns store
> + * references to same connection as the source device's out_conns.
> + *
> + * +-----------------------------+ +-----------------------------+
> + * |coresight_device | |coresight_connection |
> + * |-----------------------------| |-----------------------------|
> + * | | | |
> + * | | | dest_dev*|<--
> + * |pdata->out_conns[nr_outconns]|<->|src_dev* | |
> + * | | | | |
> + * +-----------------------------+ +-----------------------------+ |
> + * |
> + * +-----------------------------+ |
> + * |coresight_device | |
> + * |------------------------------ |
> + * | | |
> + * | pdata->in_conns[nr_inconns]|<--
> + * | |
> + * +-----------------------------+
> */
> struct coresight_connection {
> int src_port;
> @@ -180,6 +204,7 @@ struct coresight_connection {
> struct fwnode_handle *dest_fwnode;
> struct coresight_device *dest_dev;
> struct coresight_sysfs_link *link;
> + struct coresight_device *src_dev;
> };
>
> /**
> @@ -616,5 +641,6 @@ struct coresight_connection *
> coresight_add_out_conn(struct device *dev,
> struct coresight_platform_data *pdata,
> const struct coresight_connection *new_conn);
> +int coresight_add_in_conn(struct coresight_connection *conn);
>
> #endif /* _LINUX_COREISGHT_H */
> --
> 2.34.1
>
Reviewed-by: Mike Leach <mike.leach@...aro.org>
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
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