lkml.org 
[lkml]   [2018]   [Feb]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 2/3] misc: pci_endpoint_test: Handle 64-bit BARs properly
On Thu, Feb 08, 2018 at 01:33:45PM +0100, Niklas Cassel wrote:
> A 64-bit BAR uses the succeeding BAR for the upper bits,
> so we cannot simply call pci_ioremap_bar() on every single BAR.
>
> Ignore BARs that does not have a valid resource length.
>
> pci 0000:01:00.0: BAR 4: assigned [mem 0xc0300000-0xc031ffff 64bit]
> pci 0000:01:00.0: BAR 2: assigned [mem 0xc0320000-0xc03203ff 64bit]
> pci 0000:01:00.0: BAR 0: assigned [mem 0xc0320400-0xc03204ff 64bit]
> pci-endpoint-test 0000:01:00.0: can't ioremap BAR 1: [??? 0x00000000 flags 0x0]
> pci-endpoint-test 0000:01:00.0: failed to read BAR1
> pci-endpoint-test 0000:01:00.0: can't ioremap BAR 3: [??? 0x00000000 flags 0x0]
> pci-endpoint-test 0000:01:00.0: failed to read BAR3
> pci-endpoint-test 0000:01:00.0: can't ioremap BAR 5: [??? 0x00000000 flags 0x0]
> pci-endpoint-test 0000:01:00.0: failed to read BAR5
>
> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
> ---
> Lorenzo/Bjorn: pci_resource_len() seems to fix my problem,
> but is it the correct function to use here?
> If BAR[x] is a 64-bit BAR, I'm assuming that pci_resource_len() on BAR[x+1]
> will always return 0 (since BAR[x+1] cannot have any prefetchable/type bits
> when BAR[x] is 64-bit).
>
> drivers/misc/pci_endpoint_test.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c
> index 320276f42653..3af31bfdcfdd 100644
> --- a/drivers/misc/pci_endpoint_test.c
> +++ b/drivers/misc/pci_endpoint_test.c
> @@ -534,6 +534,8 @@ static int pci_endpoint_test_probe(struct pci_dev *pdev,
> }
>
> for (bar = BAR_0; bar <= BAR_5; bar++) {
> + if (pci_resource_len(pdev, bar) == 0)
> + continue;

Should not it be handled by checking the resource flags as you loop
through the bar counter and incrementing the bar counter (+1) if
IORESOURCE_MEM_64 is detected ?

I would like to get Bjorn's point of view on this since it is definitely
more comprehensive than mine.

Thanks,
Lorenzo

> base = pci_ioremap_bar(pdev, bar);
> if (!base) {
> dev_err(dev, "failed to read BAR%d\n", bar);
> --
> 2.14.2
>

\
 
 \ /
  Last update: 2018-02-26 18:27    [W:0.989 / U:0.060 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site