Patch "pmdomain: mediatek: fix race conditions with genpd" has been added to the 6.1-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    pmdomain: mediatek: fix race conditions with genpd

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     pmdomain-mediatek-fix-race-conditions-with-genpd.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 9764a2012aae4964ff1f8eb7cdc5da7edff5da0a
Author: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
Date:   Mon Dec 25 15:36:15 2023 +0200

    pmdomain: mediatek: fix race conditions with genpd
    
    [ Upstream commit c41336f4d69057cbf88fed47951379b384540df5 ]
    
    If the power domains are registered first with genpd and *after that*
    the driver attempts to power them on in the probe sequence, then it is
    possible that a race condition occurs if genpd tries to power them on
    in the same time.
    The same is valid for powering them off before unregistering them
    from genpd.
    Attempt to fix race conditions by first removing the domains from genpd
    and *after that* powering down domains.
    Also first power up the domains and *after that* register them
    to genpd.
    
    Fixes: 59b644b01cf4 ("soc: mediatek: Add MediaTek SCPSYS power domains")
    Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
    Cc: stable@xxxxxxxxxxxxxxx
    Link: https://lore.kernel.org/r/20231225133615.78993-1-eugen.hristev@xxxxxxxxxxxxx
    Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/soc/mediatek/mtk-pm-domains.c b/drivers/soc/mediatek/mtk-pm-domains.c
index 474b272f9b02d..832adb570b501 100644
--- a/drivers/soc/mediatek/mtk-pm-domains.c
+++ b/drivers/soc/mediatek/mtk-pm-domains.c
@@ -499,6 +499,11 @@ static int scpsys_add_subdomain(struct scpsys *scpsys, struct device_node *paren
 			goto err_put_node;
 		}
 
+		/* recursive call to add all subdomains */
+		ret = scpsys_add_subdomain(scpsys, child);
+		if (ret)
+			goto err_put_node;
+
 		ret = pm_genpd_add_subdomain(parent_pd, child_pd);
 		if (ret) {
 			dev_err(scpsys->dev, "failed to add %s subdomain to parent %s\n",
@@ -508,11 +513,6 @@ static int scpsys_add_subdomain(struct scpsys *scpsys, struct device_node *paren
 			dev_dbg(scpsys->dev, "%s add subdomain: %s\n", parent_pd->name,
 				child_pd->name);
 		}
-
-		/* recursive call to add all subdomains */
-		ret = scpsys_add_subdomain(scpsys, child);
-		if (ret)
-			goto err_put_node;
 	}
 
 	return 0;
@@ -526,9 +526,6 @@ static void scpsys_remove_one_domain(struct scpsys_domain *pd)
 {
 	int ret;
 
-	if (scpsys_domain_is_on(pd))
-		scpsys_power_off(&pd->genpd);
-
 	/*
 	 * We're in the error cleanup already, so we only complain,
 	 * but won't emit another error on top of the original one.
@@ -538,6 +535,8 @@ static void scpsys_remove_one_domain(struct scpsys_domain *pd)
 		dev_err(pd->scpsys->dev,
 			"failed to remove domain '%s' : %d - state may be inconsistent\n",
 			pd->genpd.name, ret);
+	if (scpsys_domain_is_on(pd))
+		scpsys_power_off(&pd->genpd);
 
 	clk_bulk_put(pd->num_clks, pd->clks);
 	clk_bulk_put(pd->num_subsys_clks, pd->subsys_clks);