Hello Damien,
On Thu, Nov 21, 2024 at 11:54:48AM +0900, Damien Le Moal wrote:
> On 11/21/24 00:57, Niklas Cassel wrote:
> > If running pci_endpoint_test.c (host side) against a version of
> > pci-epf-test.c (EP side), we will not see any capabilities being set.
> >
> > For now, only add the CAP_HAS_ALIGN_ADDR capability.
> >
> > If the CAP_HAS_ALIGN_ADDR is set, that means that the EP side supports
> > reading/writing to an address without any alignment requirements.
> >
> > Thus, if CAP_HAS_ALIGN_ADDR is set, make sure that we do not add any
> > specific padding to the buffers that we allocate (which was only made
> > in order to get the buffers to satisfy certain alignment requirements).
> >
> > Signed-off-by: Niklas Cassel <cassel@xxxxxxxxxx>
> > ---
> > drivers/misc/pci_endpoint_test.c | 21 +++++++++++++++++++++
> > 1 file changed, 21 insertions(+)
> >
> > diff --git a/drivers/misc/pci_endpoint_test.c b/drivers/misc/pci_endpoint_test.c
> > index 3aaaf47fa4ee..ab2b322410fb 100644
> > --- a/drivers/misc/pci_endpoint_test.c
> > +++ b/drivers/misc/pci_endpoint_test.c
> > @@ -69,6 +69,9 @@
> > #define PCI_ENDPOINT_TEST_FLAGS 0x2c
> > #define FLAG_USE_DMA BIT(0)
> >
> > +#define PCI_ENDPOINT_TEST_CAPS 0x30
> > +#define CAP_HAS_ALIGN_ADDR BIT(0)
> > +
> > #define PCI_DEVICE_ID_TI_AM654 0xb00c
> > #define PCI_DEVICE_ID_TI_J7200 0xb00f
> > #define PCI_DEVICE_ID_TI_AM64 0xb010
> > @@ -805,6 +808,22 @@ static const struct file_operations pci_endpoint_test_fops = {
> > .unlocked_ioctl = pci_endpoint_test_ioctl,
> > };
> >
> > +static void pci_endpoint_test_get_capabilities(struct pci_endpoint_test *test)
> > +{
> > + struct pci_dev *pdev = test->pdev;
> > + struct device *dev = &pdev->dev;
> > + u32 caps;
> > + bool has_align_addr;
> > +
> > + caps = pci_endpoint_test_readl(test, PCI_ENDPOINT_TEST_CAPS);
> > +
> > + has_align_addr = caps & CAP_HAS_ALIGN_ADDR;
> > + dev_dbg(dev, "CAP_HAS_ALIGN_ADDR: %d\n", has_align_addr);
> > +
> > + if (has_align_addr)
>
> Shouldn't this be "if (!has_align_addr)" ?
Nope. Check patch 1/2 in this series.
+ if (epc->ops->align_addr)
+ caps |= CAP_HAS_ALIGN_ADDR;
i.e. if the EP implements the addr_align callback, then we know for sure
that the EP read/write anywhere.
However, if even you as the author of the .addr_align callback get confused
by this, then perhaps we should rename things.
How about:
ep_has_align_addr_cb = caps & CAP_HAS_ALIGN_ADDR_CB;
if (ep_has_align_addr_cb)
test->alignment = 0;
or
ep_can_do_unaligned_access = caps & CAP_HAS_UNALIGNED_ACCESS;
if (ep_can_do_unaligned_access)
test->alignment = 0;
Do you have any better suggestion?
Kind regards,
Niklas
