From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Date: Fri, 18 May 2018 10:42:33 +0000 Subject: Re: [PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge Message-Id: <36cf3f12-bfe8-1c38-4d2c-b785fc64a3f6@arm.com> List-Id: References: <1526563343-28721-1-git-send-email-okaya@codeaurora.org> In-Reply-To: <1526563343-28721-1-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Sinan Kaya , linux-pci@vger.kernel.org, timur@codeaurora.org, ard.biesheuvel@linaro.org Cc: "open list:EFIFB FRAMEBUFFER DRIVER" , Bartlomiej Zolnierkiewicz , linux-arm-msm@vger.kernel.org, open list , "open list:FRAMEBUFFER LAYER" , Peter Jones , linux-arm-kernel@lists.infradead.org On 17/05/18 14:22, 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, linelength200, pages=1 > efifb: scrolling: redraw > efifb: Truecolor: size=8:8:8:8, shift$:16:8:0 > > Use the host bridge offset information to convert bus address to > resource address in the fixup. > > Signed-off-by: Sinan Kaya > --- > drivers/video/fbdev/efifb.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c > index 46a4484..ea68d5c 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; FWIW, now that I've actually gone and looked, it appears you could simplify the whole function quite a bit by getting rid of these and just using the new local resource directly, especially since the only actual use of size is an open-coded resource_contains(). > + struct pci_bus_region region; > + struct resource res; > int i; > > if (efifb_pci_dev || screen_info.orig_video_isVGA != VIDEO_TYPE_EFI) > @@ -439,6 +441,14 @@ static void efifb_fixup_resources(struct pci_dev *dev) > if (!base) > return; > > + region.start = base; > + region.end = base + size - 1; > + res.start = 0; > + res.flags = IORESOURCE_MEM; > + pcibios_bus_to_resource(dev->bus, &res, ®ion); > + if (res.start) > + base = res.start; > + > for (i = 0; i <= PCI_STD_RESOURCE_END; i++) { > struct resource *res = &dev->resource[i]; The inadvertent name shadowing here is a bit yuck, though, and I think sparse will whinge about it, so it's probably worth renaming one or the other. Robin.