On Fri, Oct 16, 2020 at 02:04:31PM +0200, marek.vasut@xxxxxxxxx wrote:
> From: Marek Vasut <marek.vasut+renesas@xxxxxxxxx>
>
> This fixes MSI operation on legacy PCI cards, which cannot issue 64bit MSIs.
> The R-Car controller only has one MSI trigger address instead of two, one
> for 64bit and one for 32bit MSI, set the address to 32bit PCIe space so that
> legacy PCI cards can also trigger MSIs.
>
> Fixes: 290c1fb35860 ("PCI: rcar: Add MSI support for PCIe")
> Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxx>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx>
> Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
> ---
> drivers/pci/controller/pcie-rcar-host.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c
> index 1194d5f3341b..ac5c7d7573a6 100644
> --- a/drivers/pci/controller/pcie-rcar-host.c
> +++ b/drivers/pci/controller/pcie-rcar-host.c
> @@ -753,7 +753,7 @@ static int rcar_pcie_enable_msi(struct rcar_pcie_host *host)
> }
>
> /* setup MSI data target */
> - msi->pages = __get_free_pages(GFP_KERNEL, 0);
> + msi->pages = __get_free_pages(GFP_KERNEL | GFP_DMA32, 0);
This does not do what you want on !CONFIG_ZONE_DMA32 (ie arm LPAE).
Can't you just pick up a non-DMA-able address < 4GB (ie outside the host
controller inbound window range) and use it as doorbell address instead ?
Thanks,
Lorenzo
> rcar_pcie_hw_enable_msi(host);
>
> return 0;
> --
> 2.28.0
>
