| Message ID | 20250109-dt-type-warnings-v1-0-0150e32e716c@kernel.org |
|---|---|
| Headers | show |
| Series | device property: Warn on (of|fwnode|device)_property_read_bool() for non-boolean properties | expand |
On Thu, Jan 09, 2025 at 01:42:06PM -0600, Rob Herring (Arm) wrote: > The use of of_property_read_bool() for non-boolean properties is > deprecated. The primary use of it was to test property presence, but > that has been replaced in favor of of_property_present(). With those > uses now fixed, add a warning to discourage new ones. > > Signed-off-by: Rob Herring (Arm) <robh@kernel.org> > --- > drivers/of/property.c | 26 ++++++++++++++++++++++++++ > include/linux/of.h | 25 +++++++------------------ > 2 files changed, 33 insertions(+), 18 deletions(-) Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Best regards, Krzysztof
Hi Rob, On Thu, Jan 9, 2025 at 8:42 PM Rob Herring (Arm) <robh@kernel.org> wrote: > The use of of_property_read_bool() for non-boolean properties is > deprecated. The primary use of it was to test property presence, but > that has been replaced in favor of of_property_present(). With those > uses now fixed, add a warning to discourage new ones. > > Signed-off-by: Rob Herring (Arm) <robh@kernel.org> Thanks for your patch, which is now commit c141ecc3cecd7647 ("of: Warn when of_property_read_bool() is used on non-boolean properties") in dt-rh/for-next. I have bisected a failure in secondary CPU bring-up on R-Car H1 (quad Cortex-A9 MPCore) to this commit: Detected Renesas R-Car Gen1 r8a7779 ES1.0 smp: Bringing up secondary CPUs ... -CPU1: thread -1, cpu 1, socket 0, mpidr 80000001 -CPU1: Spectre v2: using BPIALL workaround -CPU2: thread -1, cpu 2, socket 0, mpidr 80000002 -CPU2: Spectre v2: using BPIALL workaround -CPU3: thread -1, cpu 3, socket 0, mpidr 80000003 -CPU3: Spectre v2: using BPIALL workaround -smp: Brought up 1 node, 4 CPUs -SMP: Total of 4 processors activated (2000.00 BogoMIPS). +CPU1: failed to come online +CPU2: failed to come online +CPU3: failed to come online +smp: Brought up 1 node, 1 CPU +SMP: Total of 1 processors activated (500.00 BogoMIPS). CPU: All CPU(s) started in SVC mode. Reverting this commit on top of my work tree fixes the issue, too. However, I do not see how this commit could impact CPU bring-up? I added debug code to of_property_read_bool(), to print all look-ups. I only saw a few before CPU bring-up, nothing relevant: NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16 +OF: of_property_read_bool(interrupt-controller): 1 rcu: srcu_init: Setting srcu_struct sizes based on contention. +OF: of_property_read_bool(interrupt-controller): 1 sched_clock: 64 bits at 250MHz, resolution 4ns, wraps every 4398046511102ns clocksource: arm_global_timer: mask: 0xffffffffffffffff max_cycles: 0x7350b89c29, max_idle_ns: 881590431910 ns Switching to timer-based delay loop, resolution 4ns +OF: of_property_read_bool(interrupt-controller): 1 +OF: of_property_read_bool(always-on): 0 Console: colour dummy device 80x30 printk: legacy console [tty0] enabled Perhaps something shifted in the code layout? The obvious suspects (shmobile_boot_* and shmobile_smp_* asm code, secondary_startup(), addresses in arch/arm/mach-shmobile/platsmp-scu.c) are still at the same addresses as before... Anyone with a clue? Thanks! > --- a/drivers/of/property.c > +++ b/drivers/of/property.c > @@ -31,6 +31,32 @@ > > #include "of_private.h" > > +/** > + * of_property_read_bool - Find a property > + * @np: device node from which the property value is to be read. > + * @propname: name of the property to be searched. > + * > + * Search for a boolean property in a device node. Usage on non-boolean > + * property types is deprecated. > + * > + * Return: true if the property exists false otherwise. > + */ > +bool of_property_read_bool(const struct device_node *np, const char *propname) > +{ > + struct property *prop = of_find_property(np, propname, NULL); > + > + /* > + * Boolean properties should not have a value. Testing for property > + * presence should either use of_property_present() or just read the > + * property value and check the returned error code. > + */ > + if (prop && prop->length) > + pr_warn("%pOF: Read of boolean property '%s' with a value.\n", np, propname); > + > + return prop ? true : false; > +} > +EXPORT_SYMBOL(of_property_read_bool); > + > /** > * of_graph_is_present() - check graph's presence > * @node: pointer to device_node containing graph port > diff --git a/include/linux/of.h b/include/linux/of.h > index 1cb4eb7fc2eded2246c697c3bcaf1b85d43108ab..0cdd58ff0a4190724309ba1eddbac51b188b6136 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -311,6 +311,7 @@ extern struct device_node *of_find_node_with_property( > extern struct property *of_find_property(const struct device_node *np, > const char *name, > int *lenp); > +extern bool of_property_read_bool(const struct device_node *np, const char *propname); > extern int of_property_count_elems_of_size(const struct device_node *np, > const char *propname, int elem_size); > extern int of_property_read_u32_index(const struct device_node *np, > @@ -615,6 +616,12 @@ static inline struct device_node *of_find_compatible_node( > return NULL; > } > > +static inline bool of_property_read_bool(const struct device_node *np, > + const char *propname) > +{ > + return false; > +} > + > static inline int of_property_count_elems_of_size(const struct device_node *np, > const char *propname, int elem_size) > { > @@ -1242,24 +1249,6 @@ static inline int of_property_read_string_index(const struct device_node *np, > return rc < 0 ? rc : 0; > } > > -/** > - * of_property_read_bool - Find a property > - * @np: device node from which the property value is to be read. > - * @propname: name of the property to be searched. > - * > - * Search for a boolean property in a device node. Usage on non-boolean > - * property types is deprecated. > - * > - * Return: true if the property exists false otherwise. > - */ > -static inline bool of_property_read_bool(const struct device_node *np, > - const char *propname) > -{ > - const struct property *prop = of_find_property(np, propname, NULL); > - > - return prop ? true : false; > -} > - > /** > * of_property_present - Test if a property is present in a node > * @np: device node to search for the property. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
On Tue, Jan 14, 2025 at 12:35 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote: > > Hi Rob, > > On Thu, Jan 9, 2025 at 8:42 PM Rob Herring (Arm) <robh@kernel.org> wrote: > > The use of of_property_read_bool() for non-boolean properties is > > deprecated. The primary use of it was to test property presence, but > > that has been replaced in favor of of_property_present(). With those > > uses now fixed, add a warning to discourage new ones. > > > > Signed-off-by: Rob Herring (Arm) <robh@kernel.org> > > Thanks for your patch, which is now commit c141ecc3cecd7647 ("of: > Warn when of_property_read_bool() is used on non-boolean properties") > in dt-rh/for-next. > > I have bisected a failure in secondary CPU bring-up on R-Car H1 (quad > Cortex-A9 MPCore) to this commit: > > Detected Renesas R-Car Gen1 r8a7779 ES1.0 > smp: Bringing up secondary CPUs ... > -CPU1: thread -1, cpu 1, socket 0, mpidr 80000001 > -CPU1: Spectre v2: using BPIALL workaround > -CPU2: thread -1, cpu 2, socket 0, mpidr 80000002 > -CPU2: Spectre v2: using BPIALL workaround > -CPU3: thread -1, cpu 3, socket 0, mpidr 80000003 > -CPU3: Spectre v2: using BPIALL workaround > -smp: Brought up 1 node, 4 CPUs > -SMP: Total of 4 processors activated (2000.00 BogoMIPS). > +CPU1: failed to come online > +CPU2: failed to come online > +CPU3: failed to come online > +smp: Brought up 1 node, 1 CPU > +SMP: Total of 1 processors activated (500.00 BogoMIPS). > CPU: All CPU(s) started in SVC mode. > > Reverting this commit on top of my work tree fixes the issue, too. > However, I do not see how this commit could impact CPU bring-up? Strange. Perhaps the of_property_read_bool was inlined into some special section before? Rob
This series makes using (of|fwnode|device)_property_read_bool() on non-boolean properties give a warning when used with DT. This has been deprecated behavior for a while now. Soon we will add yet another variant of this function with a Rust binding[1]. Why not put the warning in the fwnode code? The fwnode code doesn't know the property's type as that depends on the firmware. For DT, a boolean is a property with no value. Perhaps the ACPI backend should have a warning too? I looked briefly at it, but I don't have a clue how or if that can be detected. Doesn't look like there's a specific type for booleans. In any case, that would be an additional change on top of this series. [1] https://lore.kernel.org/all/20241025-rust-platform-dev-v1-2-0df8dcf7c20b@kernel.org/ Signed-off-by: Rob Herring (Arm) <robh@kernel.org> --- Rob Herring (Arm) (2): device property: Split property reading bool and presence test ops of: Warn when of_property_read_bool() is used on non-boolean properties drivers/acpi/property.c | 1 + drivers/base/property.c | 38 ++++++++++++++++++++++++++++++++++++++ drivers/base/swnode.c | 1 + drivers/of/property.c | 33 +++++++++++++++++++++++++++++++++ include/linux/fwnode.h | 3 +++ include/linux/of.h | 29 ++++++++++------------------- include/linux/property.h | 15 +++------------ 7 files changed, 89 insertions(+), 31 deletions(-) --- base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37 change-id: 20250109-dt-type-warnings-efe52d977bb2 Best regards,