fastrpc: move ADSP duplicate session management to the driver - #1027
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Vinayak Katoch (quic-vkatoch)
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Komal Bajaj (Komal-Bajaj),
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Rajendra (rrnayak)
August 27, 2026 10:53
…form_populate of_platform_populate() only guarantees that child devices are registered, not that their probes have completed before it returns. This creates a window where fastrpc_cb_init() may not have run for all context bank nodes, leaving the channel context partially initialised. Introduce fastrpc_cb_devices_create() to iterate over child DT nodes directly and call fastrpc_cb_init() synchronously for each qcom,fastrpc-compute-cb node. This ensures all context banks are fully initialised before fastrpc_rpmsg_probe() returns. Introduce fastrpc_cb_devices_destroy() as the symmetric counterpart. Before destroying the CB platform devices, invalidate all sessions under the channel lock so that any fastrpc_user still holding a reference to the channel context cannot acquire a new session backed by a destroyed device. Since fastrpc_cb_driver is no longer needed as an independent platform driver, remove it along with its match table and remove callback. Use module_rpmsg_driver() now that only a single driver registration remains. Link: https://lore.kernel.org/all/20260923-dup-sessions-v5-1-e953133a1827@oss.qualcomm.com/ Signed-off-by: Vinayak Katoch <vinayak.katoch@oss.qualcomm.com>
…driver For ADSP, only a limited number of FastRPC context banks (CBs) are available. Each CB supports a single session, which means only a few processes can run on ADSP simultaneously. If all sessions are consumed by fastrpc daemons, no session remains available when a user application starts, causing the application to fail. To work around this, qcom,nsessions = <5> was set in DT to duplicate sessions inline during fastrpc_cb_init(). This policy does not belong in DT and should be handled at the driver level instead. Remove the qcom,nsessions DT property read and the per-CB duplication logic from fastrpc_cb_init(). After all context banks have been initialised in fastrpc_rpmsg_probe(), append FASTRPC_DUP_SESSIONS (4) copies of the last session for the ADSP domain. Link: https://lore.kernel.org/all/20260923-dup-sessions-v5-2-e953133a1827@oss.qualcomm.com/ Signed-off-by: Vinayak Katoch <vinayak.katoch@oss.qualcomm.com>
The qcom,nsessions property was used to duplicate FastRPC sessions inline during context bank initialisation. Session duplication is now handled at the driver level, making this DT property redundant. Mark it deprecated. Link: https://lore.kernel.org/all/20260923-dup-sessions-v5-3-e953133a1827@oss.qualcomm.com/ Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com> Signed-off-by: Vinayak Katoch <vinayak.katoch@oss.qualcomm.com>
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Dev Completion validation failed CR: 4508505 The change task for this CR could not be moved to Dev Complete because of the error above. Please resolve the issue in Orbit and re-run the failed Orbit check. |
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Dev Completion validation failed CR: 4508505 The change task for this CR could not be moved to Dev Complete because of the error above. Please resolve the issue in Orbit and re-run the failed Orbit check. |
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This series refactors how ADSP duplicate sessions are created, removing a DT-driven policy and replacing it with synchronous, driver-level initialisation.
[1/3] misc: fastrpc: iterate CB nodes manually instead of of_platform_populate
of_platform_populate() doesn't guarantee child probes complete before returning, leaving the channel partially initialised. Replace it with fastrpc_cb_devices_create() which calls fastrpc_cb_init() synchronously per CB node. Add fastrpc_cb_devices_destroy() as the teardown counterpart. Remove fastrpc_cb_driver as an independent platform driver and switch to module_rpmsg_driver().
[2/3] misc: fastrpc: move ADSP duplicate session creation to the driver
ADSP has few CBs; when daemons consume all sessions, user apps fail. The workaround was qcom,nsessions = <5> in DT, duplicating sessions inside fastrpc_cb_init(). Remove that and instead append FASTRPC_DUP_SESSIONS (4) copies of the last session after all CBs are initialised in fastrpc_rpmsg_probe().
[3/3] dt-bindings: misc: qcom,fastrpc: deprecate qcom,nsessions
Session duplication is now driver-managed; mark qcom,nsessions deprecated in the binding.
Link: https://lore.kernel.org/all/20260923-dup-sessions-v5-0-e953133a1827@oss.qualcomm.com/
CRs-Fixed: 4508505