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

Anshul Dalal
2026-03-06T05:05:09Z

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 :)

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) {