5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jon Hunter jonathanh@nvidia.com
commit b6bcbce3359619d05bf387d4f5cc3af63668dbaa upstream.
After commit 13a4b7fb6260 ("pmdomain: core: Leave powered-on genpds on until late_initcall_sync") was applied, the Tegra210 Jetson TX1 board failed to boot. Looking into this issue, before this commit was applied, if any of the Tegra power-domains were in 'on' state when the kernel booted, they were being turned off by the genpd core before any driver had chance to request them. This was purely by luck and a consequence of the power-domains being turned off earlier during boot. After this commit was applied, any power-domains in the 'on' state are kept on for longer during boot and therefore, may never transitioned to the off state before they are requested/used. The hang on the Tegra210 Jetson TX1 is caused because devices in some power-domains are accessed without the power-domain being turned off and on, indicating that the power-domain is not in a completely on state.
From reviewing the Tegra PMC driver code, if a power-domain is in the
'on' state there is no guarantee that all the necessary clocks associated with the power-domain are on and even if they are they would not have been requested via the clock framework and so could be turned off later. Some power-domains also have a 'clamping' register that needs to be configured as well. In short, if a power-domain is already 'on' it is difficult to know if it has been configured correctly. Given that the power-domains happened to be switched off during boot previously, to ensure that they are in a good known state on boot, fix this by switching off any power-domains that are on initially when registering the power-domains with the genpd framework.
Note that commit 05cfb988a4d0 ("soc/tegra: pmc: Initialise resets associated with a power partition") updated the tegra_powergate_of_get_resets() function to pass the 'off' to ensure that the resets for the power-domain are in the correct state on boot. However, now that we may power off a domain on boot, if it is on, it is better to move this logic into the tegra_powergate_add() function so that there is a single place where we are handling the initial state of the power-domain.
Fixes: a38045121bf4 ("soc/tegra: pmc: Add generic PM domain support") Signed-off-by: Jon Hunter jonathanh@nvidia.com Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250731121832.213671-1-jonathanh@nvidia.com Signed-off-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/soc/tegra/pmc.c | 51 +++++++++++++++++++++++++++--------------------- 1 file changed, 29 insertions(+), 22 deletions(-)
--- a/drivers/soc/tegra/pmc.c +++ b/drivers/soc/tegra/pmc.c @@ -950,7 +950,7 @@ err: }
static int tegra_powergate_of_get_resets(struct tegra_powergate *pg, - struct device_node *np, bool off) + struct device_node *np) { struct device *dev = pg->pmc->dev; int err; @@ -965,22 +965,6 @@ static int tegra_powergate_of_get_resets err = reset_control_acquire(pg->reset); if (err < 0) { pr_err("failed to acquire resets: %d\n", err); - goto out; - } - - if (off) { - err = reset_control_assert(pg->reset); - } else { - err = reset_control_deassert(pg->reset); - if (err < 0) - goto out; - - reset_control_release(pg->reset); - } - -out: - if (err) { - reset_control_release(pg->reset); reset_control_put(pg->reset); }
@@ -1025,20 +1009,43 @@ static int tegra_powergate_add(struct te goto set_available; }
- err = tegra_powergate_of_get_resets(pg, np, off); + err = tegra_powergate_of_get_resets(pg, np); if (err < 0) { dev_err(dev, "failed to get resets for %pOFn: %d\n", np, err); goto remove_clks; }
- if (!IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS)) { - if (off) - WARN_ON(tegra_powergate_power_up(pg, true)); + /* + * If the power-domain is off, then ensure the resets are asserted. + * If the power-domain is on, then power down to ensure that when is + * it turned on the power-domain, clocks and resets are all in the + * expected state. + */ + if (off) { + err = reset_control_assert(pg->reset); + if (err) { + pr_err("failed to assert resets: %d\n", err); + goto remove_resets; + } + } else { + err = tegra_powergate_power_down(pg); + if (err) { + dev_err(dev, "failed to turn off PM domain %s: %d\n", + pg->genpd.name, err); + goto remove_resets; + } + }
+ /* + * If PM_GENERIC_DOMAINS is not enabled, power-on + * the domain and skip the genpd registration. + */ + if (!IS_ENABLED(CONFIG_PM_GENERIC_DOMAINS)) { + WARN_ON(tegra_powergate_power_up(pg, true)); goto remove_resets; }
- err = pm_genpd_init(&pg->genpd, NULL, off); + err = pm_genpd_init(&pg->genpd, NULL, true); if (err < 0) { dev_err(dev, "failed to initialise PM domain %pOFn: %d\n", np, err);