[RESEND PATCH v2] PCI: dwc: Round up num_ctrls if num_vectors is less than MAX_MSI_IRQS_PER_CTRL

[Han Jingoo]

On Mon, Nov 21, 2022 Shawn Lin <shawn.lin at rock-chips.com> wrote:
>
> Some SoCs may only support 1 RC with a few MSIs support that the total number of MSIs is
> less than MAX_MSI_IRQS_PER_CTRL. In this case, num_ctrls will be zero which fails setting
> up MSI support. Fix it by rounding up num_ctrls to at least one.
>
> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>

Acked-by: Jingoo Han <jingoohan1 at gmail.com>

Best regards,
Jingoo Han

> ---
>
> Changes in v2:
> - set num_ctrls to 1 if it's less than one
>
>  drivers/pci/controller/dwc/pcie-designware-host.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index 39f3b37..cfce1e0 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -62,6 +62,8 @@ irqreturn_t dw_handle_msi_irq(struct dw_pcie_rp *pp)
>         struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>
>         num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
> +       if (num_ctrls < 1)
> +               num_ctrls = 1;
>
>         for (i = 0; i < num_ctrls; i++) {
>                 status = dw_pcie_readl_dbi(pci, PCIE_MSI_INTR0_STATUS +
> @@ -343,6 +345,8 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp)
>         if (!pp->num_vectors)
>                 pp->num_vectors = MSI_DEF_NUM_VECTORS;
>         num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
> +       if (num_ctrls < 1)
> +               num_ctrls = 1;
>
>         if (!pp->msi_irq[0]) {
>                 pp->msi_irq[0] = platform_get_irq_byname_optional(pdev, "msi");
> @@ -707,6 +711,8 @@ int dw_pcie_setup_rc(struct dw_pcie_rp *pp)
>
>         if (pp->has_msi_ctrl) {
>                 num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
> +               if (num_ctrls < 1)
> +                       num_ctrls = 1;
>
>                 /* Initialize IRQ Status array */
>                 for (ctrl = 0; ctrl < num_ctrls; ctrl++) {
> --
> 2.7.4
>