Messages in this thread Patch in this message | | | From | Vladimir Oltean <> | Subject | [PATCH 2/2] mfd: syscon: request a regmap with raw spinlocks for some devices | Date | Wed, 25 Aug 2021 23:50:41 +0300 |
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This patch solves a ls-extirq irqchip driver bug in a perhaps non-intuitive (at least non-localized) way.
The issue is that ls-extirq uses regmap, and due to the fact that it is being called by the IRQ core under raw spinlock context, it needs to use raw spinlocks itself. So it needs to request raw spinlocks from the regmap config.
All is fine so far, except the ls-extirq driver does not manage its own regmap, instead it uses syscon_node_to_regmap() to get it from the parent syscon (this driver).
Because the syscon regmap is initialized before any of the consumer drivers (ls-extirq) probe, we need to know beforehand whether to request raw spinlocks or not.
The solution seems to be to check some compatible string. The ls-extirq driver probes on quite a few NXP Layerscape SoCs, all with different compatible strings. This is potentially fragile and subject to bit rot (since the fix is not localized to the ls-extirq driver, adding new compatible strings there but not here seems plausible). Anyway, it is probably the best we can do without major rework.
Suggested-by: Mark Brown <broonie@kernel.org> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> --- drivers/mfd/syscon.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index 765c0210cb52..70da4e87b072 100644 --- a/drivers/mfd/syscon.c +++ b/drivers/mfd/syscon.c @@ -83,6 +83,22 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_clk) if (ret) reg_io_width = 4; + /* + * We might be providing a regmap to e.g. an irqchip driver, and in + * that case, normal spinlocks won't do: the IRQ core holds raw + * spinlocks, so it needs to be raw spinlocks all the way down. + * Detect those drivers here (currently "ls-extirq") and request raw + * spinlocks in the regmap config for them. + */ + if (of_device_is_compatible(np, "fsl,lx2160a-isc") || + of_device_is_compatible(np, "fsl,ls2080a-isc") || + of_device_is_compatible(np, "fsl,ls2080a-isc") || + of_device_is_compatible(np, "fsl,ls1088a-isc") || + of_device_is_compatible(np, "fsl,ls1043a-scfg") || + of_device_is_compatible(np, "fsl,ls1046a-scfg") || + of_device_is_compatible(np, "fsl,ls1021a-scfg")) + syscon_config.use_raw_spinlock = true; + ret = of_hwspin_lock_get_id(np, 0); if (ret > 0 || (IS_ENABLED(CONFIG_HWSPINLOCK) && ret == 0)) { syscon_config.use_hwlock = true; -- 2.25.1
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