Re: [PATCH v2] of: WARN on deprecated #address-cells/#size-cells handling
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2024-11-08 15:28:27
Also in:
linux-devicetree, linux-samsung-soc, lkml
Hi Rob, On 08.11.2024 14:25, Rob Herring wrote:
On Fri, Nov 8, 2024 at 5:04 AM Marek Szyprowski [off-list ref] wrote:quoted
On 06.11.2024 18:10, Rob Herring (Arm) wrote:quoted
While OpenFirmware originally allowed walking parent nodes and default root values for #address-cells and #size-cells, FDT has long required explicit values. It's been a warning in dtc for the root node since the beginning (2005) and for any parent node since 2007. Of course, not all FDT uses dtc, but that should be the majority by far. The various extracted OF devicetrees I have dating back to the 1990s (various PowerMac, OLPC, PASemi Nemo) all have explicit root node properties. The warning is disabled for Sparc as there are known systems relying on default root node values. Signed-off-by: Rob Herring (Arm) <robh@kernel.org> --- v2: - Add a define for excluded platforms to help clarify the intent is to have an exclude list and make adding platforms easier. - Also warn when walking parent nodes. --- drivers/of/base.c | 28 ++++++++++++++++++++++------ drivers/of/fdt.c | 4 ++-- 2 files changed, 24 insertions(+), 8 deletions(-)This patch landed in today's linux-next as commit 4b28a0dec185 ("of: WARN on deprecated #address-cells/#size-cells handling"). In my tests I found that it introduces warnings on almost all of my test systems. I took a look at the first one I got in my logs (Samsung Exynos Rinato board: arch/arm/boot/dts/samsung/exynos3250-rinato.dts):Thanks for the report. Let me know if any others have a different backtrace. Also, since it's a WARN_ONCE, fixing one case could expose others.
quoted
...
I'm going to fold in the following fix which should fix the warning:
This fixes all the warnings I've observed. Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
quoted hunk ↗ jump to hunk
diff --git a/drivers/of/address.c b/drivers/of/address.c index 824bb449e007..f21f4699df7a 100644 --- a/drivers/of/address.c +++ b/drivers/of/address.c@@ -333,7 +333,8 @@ static unsigned int of_bus_isa_get_flags(const __be32 *addr) static int of_bus_default_flags_match(struct device_node *np) { - return of_bus_n_addr_cells(np) == 3; + /* Check for presence first since of_bus_n_addr_cells() willwalk parents */ + return of_property_present(np, "#address-cells") && (of_bus_n_addr_cells(np) == 3); } /*@@ -701,16 +702,16 @@ const __be32 *__of_get_address(structdevice_node *dev, int index, int bar_no, if (strcmp(bus->name, "pci") && (bar_no >= 0)) return NULL; - bus->count_cells(dev, &na, &ns); - if (!OF_CHECK_ADDR_COUNT(na)) - return NULL; - /* Get "reg" or "assigned-addresses" property */ prop = of_get_property(dev, bus->addresses, &psize); if (prop == NULL) return NULL; psize /= 4; + bus->count_cells(dev, &na, &ns); + if (!OF_CHECK_ADDR_COUNT(na)) + return NULL; + onesize = na + ns; for (i = 0; psize >= onesize; psize -= onesize, prop += onesize, i++) { u32 val = be32_to_cpu(prop[0]);
Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland