From ba021fb575084f5bb69e58a0774862e5007b5d58 Mon Sep 17 00:00:00 2001 From: Tzung-Bi Shih Date: Fri, 6 Feb 2026 03:30:33 +0000 Subject: remoteproc: mediatek: Unprepare SCP clock during system suspend [ Upstream commit 35c3f72a2d55dbf52f28f4ecae51c76be1acf545 ] Prior to commit d935187cfb27 ("remoteproc: mediatek: Break lock dependency to prepare_lock"), `scp->clk` was prepared and enabled only when it needs to communicate with the SCP. The commit d935187cfb27 moved the prepare operation to remoteproc's prepare(), keeping the clock prepared as long as the SCP is running. The power consumption due to the prolonged clock preparation can be negligible when the system is running, as SCP is designed to be a very power efficient processor. However, the clock remains prepared even when the system enters system suspend. This prevents the underlying clock controller (and potentially the parent PLLs) from shutting down, which increases power consumption and may block the system from entering deep sleep states. Add suspend and resume callbacks. Unprepare the clock in suspend() if it was active and re-prepare it in resume() to ensure the clock is properly disabled during system suspend, while maintaining the "always prepared" semantics while the system is active. The driver doesn't implement .attach() callback, hence it only checks for RPROC_RUNNING. Fixes: d935187cfb27 ("remoteproc: mediatek: Break lock dependency to prepare_lock") Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Tzung-Bi Shih Link: https://lore.kernel.org/r/20260206033034.3031781-1-tzungbi@kernel.org Signed-off-by: Mathieu Poirier Signed-off-by: Sasha Levin --- drivers/remoteproc/mtk_scp.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) (limited to 'drivers/remoteproc/mtk_scp.c') diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c index 2aeb0ded165c..eb8908ea3bab 100644 --- a/drivers/remoteproc/mtk_scp.c +++ b/drivers/remoteproc/mtk_scp.c @@ -1544,12 +1544,51 @@ static const struct of_device_id mtk_scp_of_match[] = { }; MODULE_DEVICE_TABLE(of, mtk_scp_of_match); +static int __maybe_unused scp_suspend(struct device *dev) +{ + struct mtk_scp *scp = dev_get_drvdata(dev); + struct rproc *rproc = scp->rproc; + + /* + * Only unprepare if the SCP is running and holding the clock. + * + * Note: `scp_ops` doesn't implement .attach() callback, hence + * `rproc->state` can never be RPROC_ATTACHED. Otherwise, it + * should also be checked here. + */ + if (rproc->state == RPROC_RUNNING) + clk_unprepare(scp->clk); + return 0; +} + +static int __maybe_unused scp_resume(struct device *dev) +{ + struct mtk_scp *scp = dev_get_drvdata(dev); + struct rproc *rproc = scp->rproc; + + /* + * Only prepare if the SCP was running and holding the clock. + * + * Note: `scp_ops` doesn't implement .attach() callback, hence + * `rproc->state` can never be RPROC_ATTACHED. Otherwise, it + * should also be checked here. + */ + if (rproc->state == RPROC_RUNNING) + return clk_prepare(scp->clk); + return 0; +} + +static const struct dev_pm_ops scp_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(scp_suspend, scp_resume) +}; + static struct platform_driver mtk_scp_driver = { .probe = scp_probe, .remove = scp_remove, .driver = { .name = "mtk-scp", .of_match_table = mtk_scp_of_match, + .pm = &scp_pm_ops, }, }; -- cgit v1.2.3