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Message-ID: <99668e71-8c5c-9781-4f6c-5feb3395d300@arm.com>
Date: Wed, 29 Mar 2023 12:59:04 +0100
From: James Clark <james.clark@....com>
To: Suzuki K Poulose <suzuki.poulose@....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 16/03/2023 20:23, Suzuki K Poulose wrote:
> 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.
Done in v3
>
> 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.
>
Should be simplified now with coresight_fixup_device_conns() dropped.
>> 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.
Now out_conns is contiguous so adding always allocates.
>
>> 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.
Done
>
>> +/*
>> + * 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;
>
No I can change it. I was going for consistency with
coresight_add_conn() which does need the device argument because it's
called both before and after the coresight_device is created. But yeah
it makes sense to simplify this one.
>> + 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
Done
>
>
>> };
>> /**
>> @@ -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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