[PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge

[PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge

[Sinan Kaya]

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 | 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;
+	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, &region);
+	if (res.start)
+		base = res.start;
+
 	for (i = 0; i <= PCI_STD_RESOURCE_END; i++) {
 		struct resource *res = &dev->resource[i];
 
-- 
2.7.4

Re: [PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge

[Peter Jones]

On Thu, May 17, 2018 at 09:22:23AM -0400, 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>

Looks reasonable to me - Ard, do you want to take this up through the
EFI tree?

Signed-off-by: Peter Jones <pjones@redhat.com>

> ---
>  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;
> +	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, &region);
> +	if (res.start)
> +		base = res.start;
> +
>  	for (i = 0; i <= PCI_STD_RESOURCE_END; i++) {
>  		struct resource *res = &dev->resource[i];
>  
> -- 
> 2.7.4
> 

-- 
  Peter

Re: [PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge

[Ard Biesheuvel]

On 17 May 2018 at 16:55, Peter Jones <pjones@redhat.com> wrote:
> On Thu, May 17, 2018 at 09:22:23AM -0400, 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>
>
> Looks reasonable to me - Ard, do you want to take this up through the
> EFI tree?
>

Sure

> Signed-off-by: Peter Jones <pjones@redhat.com>
>

I'll take that as a reviewed-by, thanks.

>> ---
>>  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;
>> +     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, &region);
>> +     if (res.start)
>> +             base = res.start;
>> +
>>       for (i = 0; i <= PCI_STD_RESOURCE_END; i++) {
>>               struct resource *res = &dev->resource[i];
>>
>> --
>> 2.7.4
>>
>
> --
>   Peter

Re: [PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge

[Robin Murphy]

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, 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 | 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, &region);
> +	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.

Re: [PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge

[Sinan Kaya]

On 5/18/2018 6:42 AM, Robin Murphy wrote:
> 
> 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().

Posted V2 a minute ago. I did the simplification on a prior patch in order not to
mix the issues.

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge

[Bjorn Helgaas]

On Fri, May 18, 2018 at 10:20:29AM -0400, Sinan Kaya wrote:
> On 5/18/2018 6:42 AM, Robin Murphy wrote:
> > 
> > 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().
> 
> Posted V2 a minute ago. I did the simplification on a prior patch in order not to
> mix the issues.

I don't see the V2 on linux-pci, but it sounds like Ard would merge this
anyway.  So I'll drop this and you can let me know if there's anything you
need from me.

Re: [PATCH] efi/fb: Convert PCI bus address to resource if translated by the bridge

[Sinan Kaya]

Hi Bjorn,

On 6/19/2018 5:59 PM, Bjorn Helgaas wrote:
> On Fri, May 18, 2018 at 10:20:29AM -0400, Sinan Kaya wrote:
>> On 5/18/2018 6:42 AM, Robin Murphy wrote:
>>>
>>> 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().
>>
>> Posted V2 a minute ago. I did the simplification on a prior patch in order not to
>> mix the issues.
> 
> I don't see the V2 on linux-pci, but it sounds like Ard would merge this
> anyway.  So I'll drop this and you can let me know if there's anything you
> need from me.
> 

It is planned to go through fbdev tree for 4.19. 

https://patchwork.kernel.org/patch/10410895/

Feel free to review/ACK.

Sinan

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.