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SubjectRe: [RFC PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge
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On 16/05/18 19:23, Sinan Kaya wrote:
> A host bridge is allowed to remap BAR addresses using _TRA attribute in
> _CRS windows.
>
> pci_bus 0000:00: root bus resource [mem 0x80100100000-0x8011fffffff window] (bus address [0x00100000-0x1fffffff])
> pci 0000:02:00.0: reg 0x10: [mem 0x8011e000000-0x8011effffff]
>
> When a VGA device is behind such a host bridge and the resource is
> translated efifb driver is trying to do ioremap against bus address
> rather than the resource address and is failing to probe.
>
> efifb driver is having difficulty locating the base address from BAR
> address when
>
> efifb: probing for efifb
> efifb: cannot reserve video memory at 0x1e000000
> efifb: framebuffer at 0x1e000000, using 1920k, total 1875k
> efifb: mode is 800x600x32, linelength=3200, pages=1
> efifb: scrolling: redraw
> efifb: Truecolor: size=8:8:8:8, shift=24:16:8:0
>
> Use the host bridge offset information to convert bus address to
> resource address in the fixup.
>
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
> drivers/video/fbdev/efifb.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
> index 46a4484..feef02b 100644
> --- a/drivers/video/fbdev/efifb.c
> +++ b/drivers/video/fbdev/efifb.c
> @@ -428,6 +428,8 @@ static void efifb_fixup_resources(struct pci_dev *dev)
> {
> u64 base = screen_info.lfb_base;
> u64 size = screen_info.lfb_size;
> + struct pci_host_bridge *bridge;
> + struct resource_entry *window;
> int i;
>
> if (efifb_pci_dev || screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
> @@ -439,6 +441,27 @@ static void efifb_fixup_resources(struct pci_dev *dev)
> if (!base)
> return;
>
> + bridge = pci_find_host_bridge(dev->bus);
> + if (!bridge)
> + return;
> +
> + resource_list_for_each_entry(window, &bridge->windows) {
> + phys_addr_t win_start;
> + phys_addr_t win_end;
> + size_t win_size;
> +
> + if (resource_type(window->res) != IORESOURCE_MEM)
> + continue;
> +
> + win_start = window->res->start - window->offset;
> + win_end = window->res->end - window->offset;
> + win_size = window->res->end - window->res->start + 1;
> + if (win_start <= base && win_end >= base + win_size - 1) {
> + base += window->offset;
> + break;
> + }
> + }
> +

Is this not pretty much just pcibios_bus_to_resource()?

Robin.

> for (i = 0; i <= PCI_STD_RESOURCE_END; i++) {
> struct resource *res = &dev->resource[i];
>
>

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