Re: [PATCH 00/11] wifi: ath12k: Fix endianness handling in QMI

[Jeff Johnson <jeff.johnson@oss.qualcomm.com>]

On 7/16/2025 12:50 AM, Alexander Wilhelm wrote:
> Fix endianness handling in QMI firmware transfer on big-endian
> platforms. Without this fix, the firmware download fails due to
> misinterpreted data structures exchanged between the host and the
> wireless module.
> 
> The issue occurs during early bring-up on big endian systems, where QMI
> messages are not correctly parsed by the driver, leading to failed
> initialization sequences. Ensure all relevant fields are properly
> converted between CPU and little-endian format in request and response
> messages, as expected by the firmware. Attached logs showing the failure
> before the fix:
> 
>     ath12k_pci 0001:01:00.0: BAR 0: assigned [mem 0xc00000000-0xc001fffff 64bit]
>     ath12k_pci 0001:01:00.0: boot pci_mem 0xcd4148e9
>     ath12k_pci 0001:01:00.0: pci probe 17cb:1109 17cb:1109
>     ath12k_pci 0001:01:00.0: pci tcsr_soc_hw_version major 2 minor 0
>     ath12k_pci 0001:01:00.0: request MSI one vector
>     ath12k_pci 0001:01:00.0: MSI vectors: 1
>     ath12k_pci 0001:01:00.0: msi base data is 0
>     ath12k_pci 0001:01:00.0: Hardware name: qcn9274 hw2.0
>     ath12k_pci 0001:01:00.0: boot firmware request ath12k/QCN9274/hw2.0/firmware-2.bin size 15134776
>     ath12k_pci 0001:01:00.0: found fw timestamp 1722934582
>     ath12k_pci 0001:01:00.0: found m3 image ie (421880 B)
>     ath12k_pci 0001:01:00.0: found fw image ie (7229440 B)
>     ath12k_pci 0001:01:00.0: found dualmac fw image ie (7483392 B)
>     ath12k_pci 0001:01:00.0: found firmware features ie (1 B)
>     ath12k_pci 0001:01:00.0: features
>     ath12k_pci 0001:01:00.0: using fw api 2
>     ath12k_pci 0001:01:00.0: dualmac fw selected for board id: 1005
>     ath12k_pci 0001:01:00.0: Assign MSI to user: MHI, num_vectors: 3, user_base_data: 0, base_vector: 0
>     ath12k_pci 0001:01:00.0: Number of assigned MSI for MHI is 3, base vector is 0
>     ath12k_pci 0001:01:00.0: Assign MSI to user: CE, num_vectors: 1, user_base_data: 0, base_vector: 0
>     ath12k_pci 0001:01:00.0: Assign MSI to user: DP, num_vectors: 1, user_base_data: 0, base_vector: 0
>     ath12k_pci 0001:01:00.0: irq:18 group:0
>     ath12k_pci 0001:01:00.0: irq:18 group:1
>     ath12k_pci 0001:01:00.0: irq:18 group:2
>     ath12k_pci 0001:01:00.0: irq:18 group:3
>     ath12k_pci 0001:01:00.0: irq:18 group:4
>     ath12k_pci 0001:01:00.0: irq:18 group:5
>     ath12k_pci 0001:01:00.0: irq:18 group:6
>     ath12k_pci 0001:01:00.0: irq:18 group:7
>     ath12k_pci 0001:01:00.0: pci after request_irq msi_ep_base_data 0
>     ath12k_pci 0001:01:00.0: cookie:0x0
>     ath12k_pci 0001:01:00.0: WLAON_WARM_SW_ENTRY 0x2
>     ath12k_pci 0001:01:00.0: WLAON_WARM_SW_ENTRY 0x2
>     ath12k_pci 0001:01:00.0: soc reset cause:0
>     ath12k_pci 0001:01:00.0: MHISTATUS 0xff04
>     ath12k_pci 0001:01:00.0: pci link_ctl 0x0000 L0s 0 L1 0
>     ath12k_pci 0001:01:00.0: pci reg 0x3164 instance 0x11 read val 0x11
>     ath12k_pci 0001:01:00.0: setting mhi state: INIT(0)
>     ath12k_pci 0001:01:00.0: setting mhi state: POWER_ON(2)
>     ath12k_pci 0001:01:00.0: mhi notify status reason UNKNOWN
>     ath12k_pci 0001:01:00.0: mhi notify status reason MHI_CB_EE_MISSION_MODE
>     ath12k_pci 0001:01:00.0: qmi wifi fw qmi service connected
>     ath12k_pci 0001:01:00.0: phy capability resp valid 1 num_phy 2 valid 1 board_id 84934656 valid 1 single_chip_mlo_support 0
>     ath12k_pci 0001:01:00.0: intra device MLO is disabled hence skip QMI MLO cap
> 
> Alexander Wilhelm (11):
>   wifi: ath12k: fix endianness handling in QMI host capability request
>   wifi: ath12k: fix endianness handling in QMI phy capability response
>   wifi: ath12k: fix endianness handling in QMI firmware indication
>   wifi: ath12k: fix endianness handling in QMI firmware memory indication
>   wifi: ath12k: fix endianness handling in QMI respond firmware memory
>   wifi: ath12k: fix endianness handling in QMI firmware capabilities
>   wifi: ath12k: fix endianness handling in QMI bdf download
>   wifi: ath12k: fix endianness handling in QMI firmware m3 info
>   wifi: ath12k: fix endianness handling in QMI firmware wlan mode
>   wifi: ath12k: fix endianness handling in QMI wlan configuration
>   wifi: ath12k: fix endianness handling in QMI response
> 
>  drivers/net/wireless/ath/ath12k/qmi.c | 149 ++++++++++++++------------
>  drivers/net/wireless/ath/ath12k/qmi.h | 106 +++++++++---------
>  include/linux/soc/qcom/qmi.h          |   4 +-
>  3 files changed, 136 insertions(+), 123 deletions(-)
> 

Frankly I'm shocked that the low-level QMI encode/decode is not doing the
endian conversion. Since the Qualcomm internal tool that generates the data
structures has always generated structs with cpu endianess (i.e. u8, u16, u32,
etc) I just assumed that endian conversion was handled at a low level.

So should this issue be pushed down to the QMI encode/decode rather than foist
it upon every client's read & write?

/jeff