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Message-ID: <CAJ9a7ViGOFfyb2WjvVtmbOy6fxzXqBPeXBkrm54WD6sT5s3PPg@mail.gmail.com>
Date: Wed, 12 Apr 2023 15:35:18 +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 06/13] coresight: Dynamically add connections
On Tue, 4 Apr 2023 at 16:52, James Clark <james.clark@....com> wrote:
>
> Add a function for adding connections dynamically. This also removes
> the 1:1 mapping between port number and the index into the connections
> array. The only place this mapping was used was in the warning for
> duplicate output ports, which has been replaced by a search. Other
> uses of the port number already use the port member variable.
>
> Being able to dynamically add connections will allow other devices like
> CTI to re-use the connection mechanism despite not having explicit
> connections described in the DT.
>
> The connections array is now no longer sparse, so child_fwnode doesn't
> need to be checked as all connections have a target node. Because the
> array is no longer sparse, the high in and out port numbers are required
> for the refcount arrays. But these will also be removed in a later
> commit when the refcount is made a property of the connection.
>
> Signed-off-by: James Clark <james.clark@....com>
> ---
> drivers/hwtracing/coresight/coresight-core.c | 23 ++--
> .../hwtracing/coresight/coresight-platform.c | 124 +++++++++---------
> include/linux/coresight.h | 8 +-
> 3 files changed, 77 insertions(+), 78 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index f3dc320b374c..91274e7e6944 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -397,9 +397,9 @@ static void coresight_disable_link(struct coresight_device *csdev,
> link_subtype = csdev->subtype.link_subtype;
>
> if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
> - nr_conns = csdev->pdata->nr_inconns;
> + nr_conns = csdev->pdata->high_inport;
> } else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
> - nr_conns = csdev->pdata->nr_outconns;
> + nr_conns = csdev->pdata->high_outport;
> } else {
> nr_conns = 1;
> }
> @@ -1336,9 +1336,6 @@ static int coresight_orphan_match(struct device *dev, void *data)
> for (i = 0; i < i_csdev->pdata->nr_outconns; i++) {
> conn = &i_csdev->pdata->out_conns[i];
>
> - /* Skip the port if FW doesn't describe it */
> - if (!conn->dest_fwnode)
> - continue;
> /* We have found at least one orphan connection */
> if (conn->dest_dev == NULL) {
> /* Does it match this newly added device? */
> @@ -1377,8 +1374,6 @@ static int coresight_fixup_device_conns(struct coresight_device *csdev)
> for (i = 0; i < csdev->pdata->nr_outconns; i++) {
> struct coresight_connection *conn = &csdev->pdata->out_conns[i];
>
> - if (!conn->dest_fwnode)
> - continue;
> conn->dest_dev =
> coresight_find_csdev_by_fwnode(conn->dest_fwnode);
> if (conn->dest_dev && conn->dest_dev->has_conns_grp) {
> @@ -1413,7 +1408,7 @@ static int coresight_remove_match(struct device *dev, void *data)
> for (i = 0; i < iterator->pdata->nr_outconns; i++) {
> conn = &iterator->pdata->out_conns[i];
>
> - if (conn->dest_dev == NULL || conn->dest_fwnode == NULL)
> + if (conn->dest_dev == NULL)
> continue;
>
> if (csdev->dev.fwnode == conn->dest_fwnode) {
> @@ -1445,7 +1440,7 @@ static void coresight_remove_conns(struct coresight_device *csdev)
> * doesn't have at least one input port, there is no point
> * in searching all the devices.
> */
> - if (csdev->pdata->nr_inconns)
> + if (csdev->pdata->high_inport)
> bus_for_each_dev(&coresight_bustype, NULL,
> csdev, coresight_remove_match);
> }
> @@ -1552,10 +1547,8 @@ void coresight_release_platform_data(struct coresight_device *csdev,
> * Drop the refcount and clear the handle as this device
> * is going away
> */
> - if (conns[i].dest_fwnode) {
> - fwnode_handle_put(conns[i].dest_fwnode);
> - conns[i].dest_fwnode = NULL;
> - }
> + fwnode_handle_put(conns[i].dest_fwnode);
> + conns[i].dest_fwnode = NULL;
> }
> if (csdev)
> coresight_remove_conns_sysfs_group(csdev);
> @@ -1581,9 +1574,9 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
> link_subtype = desc->subtype.link_subtype;
>
> if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
> - nr_refcnts = desc->pdata->nr_inconns;
> + nr_refcnts = desc->pdata->high_inport;
> else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
> - nr_refcnts = desc->pdata->nr_outconns;
> + nr_refcnts = desc->pdata->high_outport;
> }
>
> refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
> diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
> index 566cc99a2c34..8c2029336161 100644
> --- a/drivers/hwtracing/coresight/coresight-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-platform.c
> @@ -19,22 +19,45 @@
> #include <asm/smp_plat.h>
>
> #include "coresight-priv.h"
> +
> /*
> - * coresight_alloc_conns: Allocate connections record for each output
> - * port from the device.
> + * Add an entry to the connection list and assign @conn's contents to it.
> + *
> + * If the output port is already assigned on this device, return -EINVAL
> */
> -static int coresight_alloc_conns(struct device *dev,
> - struct coresight_platform_data *pdata)
> +struct coresight_connection *
> +coresight_add_out_conn(struct device *dev,
> + struct coresight_platform_data *pdata,
> + const struct coresight_connection *new_conn)
> {
> - if (pdata->nr_outconns) {
> - pdata->out_conns = devm_kcalloc(dev, pdata->nr_outconns,
> - sizeof(*pdata->out_conns), GFP_KERNEL);
> - if (!pdata->out_conns)
> - return -ENOMEM;
> + int i;
> + struct coresight_connection *conn;
> +
> + /*
> + * Warn on any existing duplicate output port.
> + */
> + for (i = 0; i < pdata->nr_outconns; ++i) {
> + conn = &pdata->out_conns[i];
> + /* Output == -1 means ignore the port for example for helpers */
> + if (conn->src_port != -1 &&
> + conn->src_port == new_conn->src_port) {
> + dev_warn(dev, "Duplicate output port %d\n",
> + conn->src_port);
> + return ERR_PTR(-EINVAL);
> + }
> }
>
> - return 0;
> + pdata->nr_outconns++;
> + pdata->out_conns =
> + devm_krealloc_array(dev, pdata->out_conns, pdata->nr_outconns,
> + sizeof(*pdata->out_conns), GFP_KERNEL);
> + if (!pdata->out_conns)
> + return ERR_PTR(-ENOMEM);
> +
> + pdata->out_conns[pdata->nr_outconns - 1] = *new_conn;
> + return &pdata->out_conns[pdata->nr_outconns - 1];
> }
> +EXPORT_SYMBOL_GPL(coresight_add_out_conn);
>
> static struct device *
> coresight_find_device_by_fwnode(struct fwnode_handle *fwnode)
> @@ -224,7 +247,8 @@ static int of_coresight_parse_endpoint(struct device *dev,
> struct device_node *rep = NULL;
> struct device *rdev = NULL;
> struct fwnode_handle *rdev_fwnode;
> - struct coresight_connection *conn;
> + struct coresight_connection conn = {};
> + struct coresight_connection *new_conn;
>
> do {
> /* Parse the local port details */
> @@ -251,14 +275,7 @@ static int of_coresight_parse_endpoint(struct device *dev,
> break;
> }
>
> - conn = &pdata->out_conns[endpoint.port];
> - if (conn->dest_fwnode) {
> - dev_warn(dev, "Duplicate output port %d\n",
> - endpoint.port);
> - ret = -EINVAL;
> - break;
> - }
> - conn->src_port = endpoint.port;
> + conn.src_port = endpoint.port;
> /*
> * Hold the refcount to the target device. This could be
> * released via:
> @@ -267,8 +284,14 @@ static int of_coresight_parse_endpoint(struct device *dev,
> * 2) While removing the target device via
> * coresight_remove_match()
> */
> - conn->dest_fwnode = fwnode_handle_get(rdev_fwnode);
> - conn->dest_port = rendpoint.port;
> + conn.dest_fwnode = fwnode_handle_get(rdev_fwnode);
> + conn.dest_port = rendpoint.port;
> +
> + new_conn = coresight_add_out_conn(dev, pdata, &conn);
> + if (IS_ERR_VALUE(new_conn)) {
> + fwnode_handle_put(conn.dest_fwnode);
> + return PTR_ERR(new_conn);
> + }
> /* Connection record updated */
> } while (0);
>
> @@ -289,16 +312,12 @@ static int of_get_coresight_platform_data(struct device *dev,
> struct device_node *node = dev->of_node;
>
> /* Get the number of input and output port for this component */
> - of_coresight_get_ports(node, &pdata->nr_inconns, &pdata->nr_outconns);
> + of_coresight_get_ports(node, &pdata->high_inport, &pdata->high_outport);
>
> /* If there are no output connections, we are done */
> - if (!pdata->nr_outconns)
> + if (!pdata->high_outport)
> return 0;
>
> - ret = coresight_alloc_conns(dev, pdata);
> - if (ret)
> - return ret;
> -
> parent = of_coresight_get_output_ports_node(node);
> /*
> * If the DT uses obsoleted bindings, the ports are listed
> @@ -683,12 +702,14 @@ static int acpi_coresight_parse_link(struct acpi_device *adev,
> * connection information and populate the supplied coresight_platform_data
> * instance.
> */
> -static int acpi_coresight_parse_graph(struct acpi_device *adev,
> +static int acpi_coresight_parse_graph(struct device *dev,
> + struct acpi_device *adev,
> struct coresight_platform_data *pdata)
> {
> - int rc, i, nlinks;
> + int i, nlinks;
> const union acpi_object *graph;
> - struct coresight_connection *conns, *ptr;
> + struct coresight_connection conn, zero_conn = {};
> + struct coresight_connection *new_conn;
>
> pdata->nr_inconns = pdata->nr_outconns = 0;
> graph = acpi_get_coresight_graph(adev);
> @@ -699,30 +720,23 @@ static int acpi_coresight_parse_graph(struct acpi_device *adev,
> if (!nlinks)
> return 0;
>
> - /*
> - * To avoid scanning the table twice (once for finding the number of
> - * output links and then later for parsing the output links),
> - * cache the links information in one go and then later copy
> - * it to the pdata.
> - */
> - conns = devm_kcalloc(&adev->dev, nlinks, sizeof(*conns), GFP_KERNEL);
> - if (!conns)
> - return -ENOMEM;
> - ptr = conns;
> for (i = 0; i < nlinks; i++) {
> const union acpi_object *link = &graph->package.elements[3 + i];
> int dir;
>
> - dir = acpi_coresight_parse_link(adev, link, ptr);
> + conn = zero_conn;
> + dir = acpi_coresight_parse_link(adev, link, &conn);
> if (dir < 0)
> return dir;
>
> if (dir == ACPI_CORESIGHT_LINK_MASTER) {
> - if (ptr->src_port >= pdata->nr_outconns)
> - pdata->nr_outconns = ptr->src_port + 1;
> - ptr++;
> + if (conn.src_port >= pdata->high_outport)
> + pdata->high_outport = conn.src_port + 1;
> + new_conn = coresight_add_out_conn(dev, pdata, &conn);
> + if (IS_ERR(new_conn))
> + return PTR_ERR(new_conn);
> } else {
> - WARN_ON(pdata->nr_inconns == ptr->dest_port + 1);
> + WARN_ON(pdata->high_inport == conn.dest_port + 1);
> /*
> * We do not track input port connections for a device.
> * However we need the highest port number described,
> @@ -730,25 +744,11 @@ static int acpi_coresight_parse_graph(struct acpi_device *adev,
> * record for an output connection. Hence, do not move
> * the ptr for input connections
> */
> - if (ptr->dest_port >= pdata->nr_inconns)
> - pdata->nr_inconns = ptr->dest_port + 1;
> + if (conn.dest_port >= pdata->high_inport)
> + pdata->high_inport = conn.dest_port + 1;
> }
> }
>
> - rc = coresight_alloc_conns(&adev->dev, pdata);
> - if (rc)
> - return rc;
> -
> - /* Copy the connection information to the final location */
> - for (i = 0; conns + i < ptr; i++) {
> - int port = conns[i].src_port;
> -
> - /* Duplicate output port */
> - WARN_ON(pdata->out_conns[port].dest_fwnode);
> - pdata->out_conns[port] = conns[i];
> - }
> -
> - devm_kfree(&adev->dev, conns);
> return 0;
> }
>
> @@ -809,7 +809,7 @@ acpi_get_coresight_platform_data(struct device *dev,
> if (!adev)
> return -EINVAL;
>
> - return acpi_coresight_parse_graph(adev, pdata);
> + return acpi_coresight_parse_graph(dev, adev, pdata);
> }
>
> #else
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index b6f444804bf3..12fdbd03e2f7 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -104,9 +104,11 @@ union coresight_dev_subtype {
> *
> * @nr_inconns: Number of elements for the input connections.
> * @nr_outconns: Number of elements for the output connections.
> - * @out_conns: Sparse array of nr_outconns connections from this component.
> + * @out_conns: Array of nr_outconns connections from this component.
> */
> struct coresight_platform_data {
> + int high_inport;
> + int high_outport;
> int nr_inconns;
> int nr_outconns;
> struct coresight_connection *out_conns;
> @@ -609,5 +611,9 @@ static inline void coresight_write64(struct coresight_device *csdev, u64 val, u3
> extern int coresight_get_cpu(struct device *dev);
>
> struct coresight_platform_data *coresight_get_platform_data(struct device *dev);
> +struct coresight_connection *
> +coresight_add_out_conn(struct device *dev,
> + struct coresight_platform_data *pdata,
> + const struct coresight_connection *new_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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