Re: [PATCH] common: spl: spl_dfu.c: Fix warning associated with PCI subclass_code

[Mattijs Korpershoek <mkorpershoek@kernel.org>]

Hi Anshul,

On Fri, Mar 06, 2026 at 10:34, Anshul Dalal <anshuld@ti.com> wrote:

> On Thu Mar 5, 2026 at 4:08 PM IST, Siddharth Vadapalli wrote:
>> The subclass_code member of the pci_ep_header structure is a 1-byte
>> field. The macro PCI_CLASS_MEMORY_RAM is a concetation of baseclass_code
>> and subclass_code as follows:
>> 	PCI_BASE_CLASS_MEMORY: 0x05
>> 	Subclass Code for RAM: 0x00
>> 	PCI_CLASS_MEMORY_RAM:  0x0500
>> Hence, instead of extracting it via an implicity type conversion from int
>> to u8 which throws a warning, explicitly mask the bits to extract the
>> subclass_code.
>>
>> Fixes: cde77583cf0b ("spl: Add support for Device Firmware Upgrade (DFU) over PCIe")
>> Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
>
> I was able to reproduce the issue on am62x_evm_a53_defconfig with the
> following diff:
>
> 	diff --git a/arch/arm/mach-k3/include/mach/am62_spl.h b/arch/arm/mach-k3/include/mach/am62_spl.h
> 	index 2c9139d2cc0..07ae5e99e49 100644
> 	--- a/arch/arm/mach-k3/include/mach/am62_spl.h
> 	+++ b/arch/arm/mach-k3/include/mach/am62_spl.h
> 	@@ -12,6 +12,7 @@
> 	 #define BOOT_DEVICE_OSPI		0x01
> 	 #define BOOT_DEVICE_QSPI		0x02
> 	 #define BOOT_DEVICE_SPI			0x03
> 	+#define BOOT_DEVICE_PCIE			0x03
> 	 #define BOOT_DEVICE_CPGMAC		0x04
> 	 #define BOOT_DEVICE_ETHERNET_RGMII	0x04
> 	 #define BOOT_DEVICE_ETHERNET_RMII	0x05
> 	diff --git a/configs/am62x_evm_a53_defconfig b/configs/am62x_evm_a53_defconfig
> 	index 281fa3fea15..a828ad164f1 100644
> 	--- a/configs/am62x_evm_a53_defconfig
> 	+++ b/configs/am62x_evm_a53_defconfig
> 	@@ -1,4 +1,9 @@
> 	 CONFIG_ARM=y
> 	+CONFIG_SPL_PCI_DFU=y
> 	+CONFIG_SPL_PCI_ENDPOINT=y
> 	+CONFIG_SPL_PCI_DFU_SPL_LOAD_FIT_ADDRESS=0x0
> 	+CONFIG_SPL_PCI_DFU_VENDOR_ID=0x0
> 	+CONFIG_SPL_PCI_DFU_DEVICE_ID=0x0
> 	 CONFIG_ARCH_K3=y
> 	 CONFIG_SYS_MALLOC_F_LEN=0x8000
> 	 CONFIG_TI_COMMON_CMD_OPTIONS=y
>
> The patch looks good to me and fixes the build warning :)

Thanks for the diff. This was very helpful to me.
I could reproduce using the default toolchains that are provided by
buildman [1] which is ~/.buildman-toolchains/gcc-14.2.0-nolibc

[1] https://docs.u-boot.org/en/latest/build/buildman.html

Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
Tested-by: Mattijs Korpershoek <mkorpershoek@kernel.org> # am62x_evm_a53

Will apply for master.

>
> Tested-by: Anshul Dalal <anshuld@ti.com>
>
>> ---
>>
>> Hello,
>>
>> This patch is based on commit
>> f473a453b0c kbuild: Drop phandle from diff between base DT and U-Boot augmented DT if DEVICE_TREE_DEBUG=1of the master branch of U-Boot.
>>
>> Regards,
>> Siddharth.
>>
>>  common/spl/spl_dfu.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/common/spl/spl_dfu.c b/common/spl/spl_dfu.c
>> index b09f82790c9..7d21bb4d16a 100644
>> --- a/common/spl/spl_dfu.c
>> +++ b/common/spl/spl_dfu.c
>> @@ -64,7 +64,7 @@ static int dfu_over_pcie(void)
>>  	hdr.deviceid = CONFIG_SPL_PCI_DFU_DEVICE_ID;
>>  	hdr.vendorid = CONFIG_SPL_PCI_DFU_VENDOR_ID;
>>  	hdr.baseclass_code = PCI_BASE_CLASS_MEMORY;
>> -	hdr.subclass_code = PCI_CLASS_MEMORY_RAM;
>> +	hdr.subclass_code = PCI_CLASS_MEMORY_RAM & 0xff;
>>  
>>  	ret = pci_ep_write_header(dev, fn, &hdr);
>>  	if (ret) {