| Message ID | 1467191877-26017-2-git-send-email-jonathanh@nvidia.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Jun 29, 2016 at 10:17:47AM +0100, Jon Hunter wrote: > When registering the Tegra power partitions with the generic PM domain > framework, the current state of the each partition is checked and used > as the default state for the partition. However, the state of each reset > associated with the partition is not initialised and so it is possible > that the state of the resets are not in the expected state. For example, > if a partition is on, then the resets should be de-asserted and if the > partition is off, the resets should be asserted. > > There have been cases where the bootloader has powered on a partition > and only de-asserted some of the resets to some of the devices in the > partition. This can cause accesses to these devices to hang the system > when the kernel boots and attempts to probe these devices. > > Ideally, the driver for the device should ensure the reset has been > de-asserted when probing, but the resets cannot be shared between the > PMC driver (that needs to de-assert/assert the reset when turning the > partition on or off) and another driver because we cannot ensure the > reset is in the correct state. > > To ensure the resets are in the correct state, when using the generic > PM domain framework, put each reset associated with the partition in > the correct state (based upon the partition's current state) when > obtaining the resets for a partition. > > Signed-off-by: Jon Hunter <jonathanh@nvidia.com> > --- > drivers/soc/tegra/pmc.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) Applied to for-4.8/soc, thanks. Thierry
diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c index d13516981629..8a421a0b1ece 100644 --- a/drivers/soc/tegra/pmc.c +++ b/drivers/soc/tegra/pmc.c @@ -738,7 +738,7 @@ err: } static int tegra_powergate_of_get_resets(struct tegra_powergate *pg, - struct device_node *np) + struct device_node *np, bool off) { struct reset_control *rst; unsigned int i, count; @@ -758,6 +758,16 @@ static int tegra_powergate_of_get_resets(struct tegra_powergate *pg, err = PTR_ERR(pg->resets[i]); goto error; } + + if (off) + err = reset_control_assert(pg->resets[i]); + else + err = reset_control_deassert(pg->resets[i]); + + if (err) { + reset_control_put(pg->resets[i]); + goto error; + } } pg->num_resets = count; @@ -798,14 +808,14 @@ static void tegra_powergate_add(struct tegra_pmc *pmc, struct device_node *np) pg->genpd.power_on = tegra_genpd_power_on; pg->pmc = pmc; + off = !tegra_powergate_is_powered(pg->id); + if (tegra_powergate_of_get_clks(pg, np)) goto set_available; - if (tegra_powergate_of_get_resets(pg, np)) + if (tegra_powergate_of_get_resets(pg, np, off)) goto remove_clks; - off = !tegra_powergate_is_powered(pg->id); - pm_genpd_init(&pg->genpd, NULL, off); if (of_genpd_add_provider_simple(np, &pg->genpd))
When registering the Tegra power partitions with the generic PM domain framework, the current state of the each partition is checked and used as the default state for the partition. However, the state of each reset associated with the partition is not initialised and so it is possible that the state of the resets are not in the expected state. For example, if a partition is on, then the resets should be de-asserted and if the partition is off, the resets should be asserted. There have been cases where the bootloader has powered on a partition and only de-asserted some of the resets to some of the devices in the partition. This can cause accesses to these devices to hang the system when the kernel boots and attempts to probe these devices. Ideally, the driver for the device should ensure the reset has been de-asserted when probing, but the resets cannot be shared between the PMC driver (that needs to de-assert/assert the reset when turning the partition on or off) and another driver because we cannot ensure the reset is in the correct state. To ensure the resets are in the correct state, when using the generic PM domain framework, put each reset associated with the partition in the correct state (based upon the partition's current state) when obtaining the resets for a partition. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> --- drivers/soc/tegra/pmc.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)