| Message ID | 20220307034040.1111107-1-bjorn.andersson@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v4,1/7] device property: Helper to match multiple connections | expand |
On Sun, Mar 06, 2022 at 07:40:34PM -0800, Bjorn Andersson wrote: > In some cases multiple connections with the same connection id > needs to be resolved from a fwnode graph. > > One such example is when separate hardware is used for performing muxing > and/or orientation switching of the SuperSpeed and SBU lines in a USB > Type-C connector. In this case the connector needs to belong to a graph > with multiple matching remote endpoints, and the Type-C controller needs > to be able to resolve them both. > > Add a new API that allows this kind of lookup. Thanks for the update! First of all, I have noticed that subject misses the verb, something like Add or Introduce. ... > +/** > + * fwnode_connection_find_matches - Find connections from a device node > + * @fwnode: Device node with the connection > + * @con_id: Identifier for the connection > + * @data: Data for the match function > + * @match: Function to check and convert the connection description > + * @matches: Array of pointers to fill with matches (Optional) array... > + * @matches_len: Length of @matches > + * > + * Find up to @matches_len connections with unique identifier @con_id between > + * @fwnode and other device nodes. @match will be used to convert the > + * connection description to data the caller is expecting to be returned > + * through the @matches array. > + * If @matches is NULL @matches_len is ignored and the total number of resolved > + * matches is returned. I would require matches_len to be 0, see below. > + * Return: Number of matches resolved, or negative errno. > + */ > +int fwnode_connection_find_matches(struct fwnode_handle *fwnode, > + const char *con_id, void *data, > + devcon_match_fn_t match, > + void **matches, unsigned int matches_len) > +{ > + unsigned int count_graph; > + unsigned int count_ref; > + > + if (!fwnode || !match) > + return -EINVAL; > + > + count_graph = fwnode_graph_devcon_matches(fwnode, con_id, data, match, > + matches, matches_len); > + if (matches) { > + matches += count_graph; > + matches_len -= count_graph; > + } So, the valid case is matches != NULL and matches_len == 0. For example, when we have run something previously on the buffer and it becomes full. In this case we have carefully handle this case. if (matches) { matches += count_graph; if (matches_len) matches_len -= count_graph; } Seems it can be also if (matches) matches += count_graph; if (matches_len) matches_len -= count_graph; That said, do we have a test cases for this? > + count_ref = fwnode_devcon_matches(fwnode, con_id, data, match, > + matches, matches_len); > + > + return count_graph + count_ref; > +}
On Mon 07 Mar 02:05 PST 2022, Andy Shevchenko wrote: > On Sun, Mar 06, 2022 at 07:40:34PM -0800, Bjorn Andersson wrote: > > In some cases multiple connections with the same connection id > > needs to be resolved from a fwnode graph. > > > > One such example is when separate hardware is used for performing muxing > > and/or orientation switching of the SuperSpeed and SBU lines in a USB > > Type-C connector. In this case the connector needs to belong to a graph > > with multiple matching remote endpoints, and the Type-C controller needs > > to be able to resolve them both. > > > > Add a new API that allows this kind of lookup. > > Thanks for the update! > > First of all, I have noticed that subject misses the verb, something like Add > or Introduce. > Will update accordingly. > ... > > > +/** > > + * fwnode_connection_find_matches - Find connections from a device node > > + * @fwnode: Device node with the connection > > + * @con_id: Identifier for the connection > > + * @data: Data for the match function > > + * @match: Function to check and convert the connection description > > + * @matches: Array of pointers to fill with matches > > (Optional) array... > Ditto. > > + * @matches_len: Length of @matches > > + * > > + * Find up to @matches_len connections with unique identifier @con_id between > > + * @fwnode and other device nodes. @match will be used to convert the > > + * connection description to data the caller is expecting to be returned > > + * through the @matches array. > > > + * If @matches is NULL @matches_len is ignored and the total number of resolved > > + * matches is returned. > > I would require matches_len to be 0, see below. > > > + * Return: Number of matches resolved, or negative errno. > > + */ > > +int fwnode_connection_find_matches(struct fwnode_handle *fwnode, > > + const char *con_id, void *data, > > + devcon_match_fn_t match, > > + void **matches, unsigned int matches_len) > > +{ > > + unsigned int count_graph; > > + unsigned int count_ref; > > + > > + if (!fwnode || !match) > > + return -EINVAL; > > + > > + count_graph = fwnode_graph_devcon_matches(fwnode, con_id, data, match, > > + matches, matches_len); > > > + if (matches) { > > + matches += count_graph; > > + matches_len -= count_graph; > > + } > > So, the valid case is matches != NULL and matches_len == 0. For example, when > we have run something previously on the buffer and it becomes full. > > In this case we have carefully handle this case. > > if (matches) { > matches += count_graph; > if (matches_len) > matches_len -= count_graph; When matches is non-NULL, both the sub-functions are limited by matches_len and as such count_graph <= matches_len. As such matches_len >= 0. In the event that the originally passed matches_len was 0, then count_graph will be 0 and matches_len will remain 0. I therefor don't see that this additional check changes things. > } > > Seems it can be also > > if (matches) > matches += count_graph; > > if (matches_len) > matches_len -= count_graph; We covered the case of matches && (matches_len || !matches_len) above. For the case of !matches && matches_len, this added conditional would cause matches_len to be extra ignored by keeping it at 0, but per kernel-doc and implementation we ignore all other values already. Note that this is in contrast from vsnprintf() where the code will continue to produce results, only store the first "matches_len" entires and return the final count. Unfortunately we can't follow such semantics here, instead it is clearly documented in the kernel-doc that @matches_len is ignored when @matches is NULL. So unless I'm missing something I don't see what you gain over keeping the check on only matches. > > That said, do we have a test cases for this? > I looked briefly at adding some kunit tests for this, but was discourage by the prospect of building up the graphs to run the tests against. Regards, Bjorn > > + count_ref = fwnode_devcon_matches(fwnode, con_id, data, match, > > + matches, matches_len); > > + > > + return count_graph + count_ref; > > +} > > -- > With Best Regards, > Andy Shevchenko > >
diff --git a/drivers/base/property.c b/drivers/base/property.c index c0e94cce9c29..7fccb0587855 100644 --- a/drivers/base/property.c +++ b/drivers/base/property.c @@ -1218,6 +1218,40 @@ fwnode_graph_devcon_match(struct fwnode_handle *fwnode, const char *con_id, return NULL; } +static unsigned int fwnode_graph_devcon_matches(struct fwnode_handle *fwnode, + const char *con_id, void *data, + devcon_match_fn_t match, + void **matches, + unsigned int matches_len) +{ + struct fwnode_handle *node; + struct fwnode_handle *ep; + unsigned int count = 0; + void *ret; + + fwnode_graph_for_each_endpoint(fwnode, ep) { + if (matches && count >= matches_len) { + fwnode_handle_put(ep); + break; + } + + node = fwnode_graph_get_remote_port_parent(ep); + if (!fwnode_device_is_available(node)) { + fwnode_handle_put(node); + continue; + } + + ret = match(node, con_id, data); + fwnode_handle_put(node); + if (ret) { + if (matches) + matches[count] = ret; + count++; + } + } + return count; +} + static void * fwnode_devcon_match(struct fwnode_handle *fwnode, const char *con_id, void *data, devcon_match_fn_t match) @@ -1240,6 +1274,37 @@ fwnode_devcon_match(struct fwnode_handle *fwnode, const char *con_id, return NULL; } +static unsigned int fwnode_devcon_matches(struct fwnode_handle *fwnode, + const char *con_id, void *data, + devcon_match_fn_t match, + void **matches, + unsigned int matches_len) +{ + struct fwnode_handle *node; + unsigned int count = 0; + unsigned int i; + void *ret; + + for (i = 0; ; i++) { + if (matches && count >= matches_len) + break; + + node = fwnode_find_reference(fwnode, con_id, i); + if (IS_ERR(node)) + break; + + ret = match(node, NULL, data); + fwnode_handle_put(node); + if (ret) { + if (matches) + matches[count] = ret; + count++; + } + } + + return count; +} + /** * fwnode_connection_find_match - Find connection from a device node * @fwnode: Device node with the connection @@ -1267,3 +1332,47 @@ void *fwnode_connection_find_match(struct fwnode_handle *fwnode, return fwnode_devcon_match(fwnode, con_id, data, match); } EXPORT_SYMBOL_GPL(fwnode_connection_find_match); + +/** + * fwnode_connection_find_matches - Find connections from a device node + * @fwnode: Device node with the connection + * @con_id: Identifier for the connection + * @data: Data for the match function + * @match: Function to check and convert the connection description + * @matches: Array of pointers to fill with matches + * @matches_len: Length of @matches + * + * Find up to @matches_len connections with unique identifier @con_id between + * @fwnode and other device nodes. @match will be used to convert the + * connection description to data the caller is expecting to be returned + * through the @matches array. + * If @matches is NULL @matches_len is ignored and the total number of resolved + * matches is returned. + * + * Return: Number of matches resolved, or negative errno. + */ +int fwnode_connection_find_matches(struct fwnode_handle *fwnode, + const char *con_id, void *data, + devcon_match_fn_t match, + void **matches, unsigned int matches_len) +{ + unsigned int count_graph; + unsigned int count_ref; + + if (!fwnode || !match) + return -EINVAL; + + count_graph = fwnode_graph_devcon_matches(fwnode, con_id, data, match, + matches, matches_len); + + if (matches) { + matches += count_graph; + matches_len -= count_graph; + } + + count_ref = fwnode_devcon_matches(fwnode, con_id, data, match, + matches, matches_len); + + return count_graph + count_ref; +} +EXPORT_SYMBOL_GPL(fwnode_connection_find_matches); diff --git a/include/linux/property.h b/include/linux/property.h index 4cd4b326941f..de7ff336d2c8 100644 --- a/include/linux/property.h +++ b/include/linux/property.h @@ -447,6 +447,11 @@ static inline void *device_connection_find_match(struct device *dev, return fwnode_connection_find_match(dev_fwnode(dev), con_id, data, match); } +int fwnode_connection_find_matches(struct fwnode_handle *fwnode, + const char *con_id, void *data, + devcon_match_fn_t match, + void **matches, unsigned int matches_len); + /* -------------------------------------------------------------------------- */ /* Software fwnode support - when HW description is incomplete or missing */
In some cases multiple connections with the same connection id needs to be resolved from a fwnode graph. One such example is when separate hardware is used for performing muxing and/or orientation switching of the SuperSpeed and SBU lines in a USB Type-C connector. In this case the connector needs to belong to a graph with multiple matching remote endpoints, and the Type-C controller needs to be able to resolve them both. Add a new API that allows this kind of lookup. Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> --- Changes since v3: - fwnode_connection_find_matches() should not adjust matches before calling fwnode_devcon_matches() - Replaced return from within the loops with break - Changed "count >= matches_len && matches" to "matches && count >= matches_len", to denote the significance of "matches" Changes since v2: - Allow the caller of the new api to pass a matches of NULL, to count possible matches. I previously argued that this will cause memory leaks, but Andy pointed out that this depends on the caller and the match function. - Fixed spelling mistakes in commit message and kernel-doc. - Use two "count" variables to make the math clearer. Changes since v1: - Iterator in fwnode_devcon_matches() is now unsigned. - fwnode_handle_put() node for unavailable nodes. - Extended commit message on the subject of supporting dynamically sized "matches" array. drivers/base/property.c | 109 +++++++++++++++++++++++++++++++++++++++ include/linux/property.h | 5 ++ 2 files changed, 114 insertions(+)