Re: [PATCH kernel 2/4] pci/doe: Support discovery version

Bjorn Helgaas
2024-02-08T22:00:29Z

On Thu, Feb 01, 2024 at 05:02:26PM +1100, Alexey Kardashevskiy wrote:
> PCIe spec v6.1 defines a "DOE Discovery Version" field in the DOE Discovery
> Request Data Object Contents (3rd DW) as:

Please include spec section number, e.g., "PCIe r6.1, sec xx.xx".

(Also note PCI-SIG uses "revision" as the major, "version" as the
minor, so this would be "PCIe r6.1", not "PCIe v6.1".)

> 15:8 DOE Discovery Version – must be 02h if the Capability Version in
> the Data Object Exchange Extended Capability is 02h or greater.
>
> Add support for the version on devices with the DOE v2 capability.
>
> Signed-off-by: Alexey Kardashevskiy <aik@amd.com>
> ---
> include/uapi/linux/pci_regs.h | 1 +
> drivers/pci/doe.c | 11 ++++++++---
> 2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index a39193213ff2..b9c681f14181 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -1144,6 +1144,7 @@
> #define PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH 0x0003ffff
>
> #define PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX 0x000000ff
> +#define PCI_DOE_DATA_OBJECT_DISC_REQ_3_DISCOVER_VER 0x0000ff00
> #define PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID 0x0000ffff
> #define PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL 0x00ff0000
> #define PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX 0xff000000
> diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
> index 61f0531d2b1d..f57def002175 100644
> --- a/drivers/pci/doe.c
> +++ b/drivers/pci/doe.c
> @@ -381,11 +381,13 @@ static void pci_doe_task_complete(struct pci_doe_task *task)
> complete(task->private);
> }
>
> -static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid,
> +static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 capver, u8 *index, u16 *vid,
> u8 *protocol)
> {
> + u32 disver = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_DISCOVER_VER,
> + (capver >= 2) ? 2 : 0);
> u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX,
> - *index);
> + *index) | disver;
> __le32 request_pl_le = cpu_to_le32(request_pl);
> __le32 response_pl_le;
> u32 response_pl;
> @@ -419,13 +421,16 @@ static int pci_doe_cache_protocols(struct pci_doe_mb *doe_mb)
> {
> u8 index = 0;
> u8 xa_idx = 0;
> + u32 hdr = 0;
> +
> + pci_read_config_dword(doe_mb->pdev, doe_mb->cap_offset, &hdr);
>
> do {
> int rc;
> u16 vid;
> u8 prot;
>
> - rc = pci_doe_discovery(doe_mb, &index, &vid, &prot);
> + rc = pci_doe_discovery(doe_mb, PCI_EXT_CAP_VER(hdr), &index, &vid, &prot);
> if (rc)
> return rc;
>
> --
> 2.41.0
>