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linux/Documentation/driver-api/interconnect.rst

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interconnect: Add generic on-chip interconnect API This patch introduces a new API to get requirements and configure the interconnect buses across the entire chipset to fit with the current demand. The API is using a consumer/provider-based model, where the providers are the interconnect buses and the consumers could be various drivers. The consumers request interconnect resources (path) between endpoints and set the desired constraints on this data flow path. The providers receive requests from consumers and aggregate these requests for all master-slave pairs on that path. Then the providers configure each node along the path to support a bandwidth that satisfies all bandwidth requests that cross through that node. The topology could be complicated and multi-tiered and is SoC specific. Reviewed-by: Evan Green <evgreen@chromium.org> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-16 18:10:56 +02:00
docs: driver-api: make interconnect title quieter This makes it consistent with the other headings in the Linux driver implementer's API guide. Signed-off-by: Louis Taylor <louis@kragniz.eu> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-11-01 19:33:14 +00:00
interconnect: Add generic on-chip interconnect API This patch introduces a new API to get requirements and configure the interconnect buses across the entire chipset to fit with the current demand. The API is using a consumer/provider-based model, where the providers are the interconnect buses and the consumers could be various drivers. The consumers request interconnect resources (path) between endpoints and set the desired constraints on this data flow path. The providers receive requests from consumers and aggregate these requests for all master-slave pairs on that path. Then the providers configure each node along the path to support a bandwidth that satisfies all bandwidth requests that cross through that node. The topology could be complicated and multi-tiered and is SoC specific. Reviewed-by: Evan Green <evgreen@chromium.org> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-16 18:10:56 +02:00
docs: interconnect: Add provider APIs to documentation The "Interconnect providers" section currently only includes data structures from include/linux/interconnect-provider.h. Include drivers/interconnect/core.c to extract provider-specific API documentation. The :functions: directive is used to prevent mixing with consumer APIs. Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Message-ID: <20260312175341.2944154-2-visitorckw@gmail.com>
2026-03-12 17:53:40 +00:00
interconnect: Add generic on-chip interconnect API This patch introduces a new API to get requirements and configure the interconnect buses across the entire chipset to fit with the current demand. The API is using a consumer/provider-based model, where the providers are the interconnect buses and the consumers could be various drivers. The consumers request interconnect resources (path) between endpoints and set the desired constraints on this data flow path. The providers receive requests from consumers and aggregate these requests for all master-slave pairs on that path. Then the providers configure each node along the path to support a bandwidth that satisfies all bandwidth requests that cross through that node. The topology could be complicated and multi-tiered and is SoC specific. Reviewed-by: Evan Green <evgreen@chromium.org> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-16 18:10:56 +02:00
docs: interconnect: Document consumer APIs and drop outdated text The documentation currently states that consumer interfaces are not documented, which is no longer true. Remove the outdated claim and include the existing kernel-doc from drivers/interconnect/core.c (filtered for consumer APIs) and drivers/interconnect/bulk.c. Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Message-ID: <20260312175341.2944154-3-visitorckw@gmail.com>
2026-03-12 17:53:41 +00:00
interconnect: Add interconnect_graph file to debugfs The interconnect graphs can be difficult to understand and the current "interconnect_summary" file doesn't even display links in any way. Add a new "interconnect_graph" file to debugfs in the graphviz "dot" format which describes interconnect providers, nodes and links. The file is human-readable and can be visualized by piping through graphviz. Example: ssh $TARGET cat /sys/kernel/debug/interconnect/interconnect_graph \ | dot -Tsvg > interconnect_graph.svg Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
2019-11-19 00:34:01 +02:00
interconnect: Add debugfs test client It's often useful during test, debug, and development to issue path votes from shell. Add a debugfs client for this purpose. Example usage: cd /sys/kernel/debug/interconnect/test-client/ # Configure node endpoints for the path from CPU to DDR on # qcom/sm8550. echo chm_apps > src_node echo ebi > dst_node # Get path between src_node and dst_node. This is only # necessary after updating the node endpoints. echo 1 > get # Set desired BW to 1GBps avg and 2GBps peak. echo 1000000 > avg_bw echo 2000000 > peak_bw # Vote for avg_bw and peak_bw on the latest path from "get". # Voting for multiple paths is possible by repeating this # process for different nodes endpoints. echo 1 > commit Allowing userspace to directly enable and set bus rates can be dangerous So, following in the footsteps of the regmap [0] and clk [1] frameworks, keep these userspace controls compile-time disabled without Kconfig options to enable them. Enabling this will require code changes to define INTERCONNECT_ALLOW_WRITE_DEBUGFS. [0] commit 09c6ecd39410 ("regmap: Add support for writing to regmap registers via debugfs") [1] commit 37215da5553e ("clk: Add support for setting clk_rate via debugfs") Signed-off-by: Mike Tipton <quic_mdtipton@quicinc.com> Link: https://lore.kernel.org/r/20230807142914.12480-4-quic_mdtipton@quicinc.com Signed-off-by: Georgi Djakov <djakov@kernel.org>
2023-08-07 07:29:14 -07:00