Re: [PATCH 2/2] misc: pci_endpoint_test: Add support for capabilities

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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)" ?

> +		test->alignment = 0;
> +}
> +
>  static int pci_endpoint_test_probe(struct pci_dev *pdev,
>  				   const struct pci_device_id *ent)
>  {
> @@ -906,6 +925,8 @@ static int pci_endpoint_test_probe(struct pci_dev *pdev,
>  		goto err_kfree_test_name;
>  	}
>  
> +	pci_endpoint_test_get_capabilities(test);
> +
>  	misc_device = &test->miscdev;
>  	misc_device->minor = MISC_DYNAMIC_MINOR;
>  	misc_device->name = kstrdup(name, GFP_KERNEL);


-- 
Damien Le Moal
Western Digital Research




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