On 6/25/2025 12:50 AM, Govind Singh wrote:
> This patch adds two module parameters to the ath12k PCI driver.
>
> - ath12k_msi_mode: Allows selecting the MSI allocation mode.
> * 0 = multi-vector MSI (default)
> * 1 = single-vector MSI
>
> - ath12k_32bit_msi: Forces the use of 32-bit MSI addressing
> by setting pdev->no_64bit_msi = 1 before IRQ vector allocation.
>
> These options are useful for working around hardware or platform
> limitations(ex: i.MX 8M Plus) where 64-bit MSI or multi-vector MSI
> allocations fails or cause stability issues.
>
> The original MSI allocation logic remains unchanged unless the
> parameters are explicitly set via modprobe or kernel boot options.
>
> Tested-on: QCN9274 hw2.0 WLAN.WBE.1.4.1-00103-QCAHKSWPL_SILICONZ-1 with
> i.MX 8M Plus SOC
> Signed-off-by: Govind Singh <govind.sk85@xxxxxxxxx>
Like I commented in the Bugzilla, this is not a ath12k issue. Fix/workarounds need to go
to the PCIe controller driver, not its users.
> ---
> drivers/net/wireless/ath/ath12k/pci.c | 25 +++++++++++++++++++++----
> drivers/net/wireless/ath/ath12k/pci.h | 5 +++++
> 2 files changed, 26 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath12k/pci.c b/drivers/net/wireless/ath/ath12k/pci.c
> index 1f3cfd9b89fd..4f58cb1e03f6 100644
> --- a/drivers/net/wireless/ath/ath12k/pci.c
> +++ b/drivers/net/wireless/ath/ath12k/pci.c
> @@ -45,6 +45,14 @@
> #define DOMAIN_NUMBER_MASK GENMASK(7, 4)
> #define BUS_NUMBER_MASK GENMASK(3, 0)
>
> +int ath12k_msi_mode;
> +module_param(ath12k_msi_mode, int, 0644);
> +MODULE_PARM_DESC(ath12k_msi_mode, "MSI mode: 0 = multi-vector (default), 1 = single-vector");
> +
> +bool ath12k_32bit_msi;
> +module_param(ath12k_32bit_msi, bool, 0644);
> +MODULE_PARM_DESC(ath12k_32bit_msi, "Force 32-bit MSI addressing");
> +
> static const struct pci_device_id ath12k_pci_id_table[] = {
> { PCI_VDEVICE(QCOM, QCN9274_DEVICE_ID) },
> { PCI_VDEVICE(QCOM, WCN7850_DEVICE_ID) },
> @@ -773,10 +781,19 @@ static int ath12k_pci_msi_alloc(struct ath12k_pci *ab_pci)
> int num_vectors;
> int ret;
>
> - num_vectors = pci_alloc_irq_vectors(ab_pci->pdev,
> - msi_config->total_vectors,
> - msi_config->total_vectors,
> - PCI_IRQ_MSI);
> + /* Set 32-bit MSI flag early if requested */
> + if (ath12k_32bit_msi)
> + ab_pci->pdev->no_64bit_msi = 1;
> +
> + /* Force single MSI mode if requested */
> + if (ath12k_msi_mode == ATH12K_MSI_VEC_SINGLE) {
> + num_vectors = -EINVAL; /* Force fallback path */
> + } else {
> + num_vectors = pci_alloc_irq_vectors(ab_pci->pdev,
> + msi_config->total_vectors,
> + msi_config->total_vectors,
> + PCI_IRQ_MSI);
> + }
>
> if (num_vectors == msi_config->total_vectors) {
> set_bit(ATH12K_PCI_FLAG_MULTI_MSI_VECTORS, &ab_pci->flags);
> diff --git a/drivers/net/wireless/ath/ath12k/pci.h b/drivers/net/wireless/ath/ath12k/pci.h
> index d1ec8aad7f6c..4fa8bb619cd9 100644
> --- a/drivers/net/wireless/ath/ath12k/pci.h
> +++ b/drivers/net/wireless/ath/ath12k/pci.h
> @@ -92,6 +92,11 @@ enum ath12k_pci_flags {
> ATH12K_PCI_FLAG_MULTI_MSI_VECTORS,
> };
>
> +enum ath12k_msi_mode {
> + ATH12K_MSI_VEC_AUTO = 0,
> + ATH12K_MSI_VEC_SINGLE = 1,
> +};
> +
> struct ath12k_pci_ops {
> int (*wakeup)(struct ath12k_base *ab);
> void (*release)(struct ath12k_base *ab);
