On Tue, 01 Feb 2022 14:06:32 -0800
Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> From: Ben Widawsky <ben.widawsky@xxxxxxxxx>
>
> The PCIe device DVSEC, defined in the CXL 2.0 spec, 8.1.3 is required to
> be implemented by CXL 2.0 endpoint devices. In preparation for consuming
> this information in a new cxl_mem driver, retrieve the CXL DVSEC
> position and warn about the implications of not finding it. Allow for
> mailbox operation even if the CXL DVSEC is missing.
>
> Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> ---
> Changes since v3:
> - Move the s/device_dvsec/cxl_dvsec/ rename one patch sooner (Jonathan)
> - Warn, don't fail, when CXL DVSEC not found
>
> drivers/cxl/cxlmem.h | 2 ++
> drivers/cxl/pci.c | 6 ++++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 90d67fff5bed..5cf5329e13a9 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -98,6 +98,7 @@ struct cxl_mbox_cmd {
> *
> * @dev: The device associated with this CXL state
> * @regs: Parsed register blocks
> + * @cxl_dvsec: Offset to the PCIe device DVSEC
> * @payload_size: Size of space for payload
> * (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
> * @lsa_size: Size of Label Storage Area
> @@ -126,6 +127,7 @@ struct cxl_dev_state {
> struct device *dev;
>
> struct cxl_regs regs;
> + int cxl_dvsec;
>
> size_t payload_size;
> size_t lsa_size;
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index bf14c365ea33..c94002166084 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -408,6 +408,12 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> if (IS_ERR(cxlds))
> return PTR_ERR(cxlds);
>
> + cxlds->cxl_dvsec = pci_find_dvsec_capability(
> + pdev, PCI_DVSEC_VENDOR_ID_CXL, CXL_DVSEC_PCIE_DEVICE);
> + if (!cxlds->cxl_dvsec)
> + dev_warn(&pdev->dev,
> + "Device DVSEC not present, skip CXL.mem init\n");
> +
> rc = cxl_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
> if (rc)
> return rc;
>
