lkml.org 
[lkml]   [2019]   [May]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2] PCI: endpoint: Skip odd BAR when skipping 64bit BAR
From
Date
Hi Alan,

On 25/05/19 12:20 AM, Alan Mikhak wrote:
> Hi Kishon,
>
> Yes. This change is still applicable even when the platform specifies
> that it only supports 64-bit BARs by setting the bar_fixed_64bit
> member of epc_features.
>
> The issue being fixed is this: If the 'continue' statement is executed
> within the loop, the loop index 'bar' needs to advanced by two, not
> one, when the BAR is 64-bit. Otherwise the next loop iteration will be
> on an odd BAR which doesn't exist.

IIUC you are fixing the case where the BAR is "reserved" (specified in
epc_features) and is also a 64-bit BAR?

If 2 consecutive BARs are marked as reserved in reserved_bar of epc_features,
the result should be the same right?

Thanks
Kishon

>
> The PCI_BASE_ADDRESS_MEM_TYPE_64 flag in epf_bar->flag reflects the
> value set by the platform in the bar_fixed_64bit member of
> epc_features.
>
> This patch moves the checking of PCI_BASE_ADDRESS_MEM_TYPE_64 in
> epf_bar->flags to before the 'continue' statement to advance the 'bar'
> loop index accordingly. The comment you see about 'pci_epc_set_bar()'
> preceding the moved code is the original comment and was also moved
> along with the code.
>
> Regards,
> Alan Mikhak
>
> On Fri, May 24, 2019 at 1:51 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>>
>> Hi,
>>
>> On 24/05/19 5:25 AM, Alan Mikhak wrote:
>>> +Bjorn Helgaas, +Gustavo Pimentel, +Wen Yang, +Kangjie Lu
>>>
>>> On Thu, May 23, 2019 at 2:55 PM Alan Mikhak <alan.mikhak@sifive.com> wrote:
>>>>
>>>> Always skip odd bar when skipping 64bit BARs in pci_epf_test_set_bar()
>>>> and pci_epf_test_alloc_space().
>>>>
>>>> Otherwise, pci_epf_test_set_bar() will call pci_epc_set_bar() on odd loop
>>>> index when skipping reserved 64bit BAR. Moreover, pci_epf_test_alloc_space()
>>>> will call pci_epf_alloc_space() on bind for odd loop index when BAR is 64bit
>>>> but leaks on subsequent unbind by not calling pci_epf_free_space().
>>>>
>>>> Signed-off-by: Alan Mikhak <alan.mikhak@sifive.com>
>>>> Reviewed-by: Paul Walmsley <paul.walmsley@sifive.com>
>>>> ---
>>>> drivers/pci/endpoint/functions/pci-epf-test.c | 25 ++++++++++++-------------
>>>> 1 file changed, 12 insertions(+), 13 deletions(-)
>>>>
>>>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>>>> index 27806987e93b..96156a537922 100644
>>>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>>>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>>>> @@ -389,7 +389,7 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
>>>>
>>>> static int pci_epf_test_set_bar(struct pci_epf *epf)
>>>> {
>>>> - int bar;
>>>> + int bar, add;
>>>> int ret;
>>>> struct pci_epf_bar *epf_bar;
>>>> struct pci_epc *epc = epf->epc;
>>>> @@ -400,8 +400,14 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
>>>>
>>>> epc_features = epf_test->epc_features;
>>>>
>>>> - for (bar = BAR_0; bar <= BAR_5; bar++) {
>>>> + for (bar = BAR_0; bar <= BAR_5; bar += add) {
>>>> epf_bar = &epf->bar[bar];
>>>> + /*
>>>> + * pci_epc_set_bar() sets PCI_BASE_ADDRESS_MEM_TYPE_64
>>>> + * if the specific implementation required a 64-bit BAR,
>>>> + * even if we only requested a 32-bit BAR.
>>>> + */
>>
>> set_bar shouldn't set PCI_BASE_ADDRESS_MEM_TYPE_64. If a platform supports only
>> 64-bit BAR, that should be specified in epc_features bar_fixed_64bit member.
>>
>> Thanks
>> Kishon

\
 
 \ /
  Last update: 2019-05-31 06:38    [W:0.042 / U:7.792 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site