Re: [PATCH v2 08/27] ocxl: Save the device serial number in ocxl_fn

Jonathan Cameron
2020-02-03T12:53:52Z

On Tue, 3 Dec 2019 14:46:36 +1100
Alastair D'Silva <alastair@au1.ibm.com> wrote:

> From: Alastair D'Silva <alastair@d-silva.org>
>
> This patch retrieves the serial number of the card and makes it available
> to consumers of the ocxl driver via the ocxl_fn struct.
>
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
> Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
> drivers/misc/ocxl/config.c | 46 ++++++++++++++++++++++++++++++++++++++
> include/misc/ocxl.h | 1 +
> 2 files changed, 47 insertions(+)
>
> diff --git a/drivers/misc/ocxl/config.c b/drivers/misc/ocxl/config.c
> index fb0c3b6f8312..a9203c309365 100644
> --- a/drivers/misc/ocxl/config.c
> +++ b/drivers/misc/ocxl/config.c
> @@ -71,6 +71,51 @@ static int find_dvsec_afu_ctrl(struct pci_dev *dev, u8 afu_idx)
> return 0;
> }
>
> +/**

Make sure anything you mark as kernel doc with /** is valid
kernel-doc.

> + * Find a related PCI device (function 0)
> + * @device: PCI device to match
> + *
> + * Returns a pointer to the related device, or null if not found
> + */
> +static struct pci_dev *get_function_0(struct pci_dev *dev)
> +{
> + unsigned int devfn = PCI_DEVFN(PCI_SLOT(dev->devfn), 0); // Look for function 0

Not sure the trailing comment adds much.

I'd personally not bother with this wrapper at all and just call
the pci functions directly where needed.

> +
> + return pci_get_domain_bus_and_slot(pci_domain_nr(dev->bus),
> + dev->bus->number, devfn);
> +}
> +
> +static void read_serial(struct pci_dev *dev, struct ocxl_fn_config *fn)
> +{
> + u32 low, high;
> + int pos;
> +
> + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DSN);
> + if (pos) {
> + pci_read_config_dword(dev, pos + 0x04, &low);
> + pci_read_config_dword(dev, pos + 0x08, &high);
> +
> + fn->serial = low | ((u64)high) << 32;
> +
> + return;
> + }
> +
> + if (PCI_FUNC(dev->devfn) != 0) {
> + struct pci_dev *related = get_function_0(dev);
> +
> + if (!related) {
> + fn->serial = 0;
> + return;
> + }
> +
> + read_serial(related, fn);
> + pci_dev_put(related);
> + return;
> + }
> +
> + fn->serial = 0;
> +}
> +
> static void read_pasid(struct pci_dev *dev, struct ocxl_fn_config *fn)
> {
> u16 val;
> @@ -208,6 +253,7 @@ int ocxl_config_read_function(struct pci_dev *dev, struct ocxl_fn_config *fn)
> int rc;
>
> read_pasid(dev, fn);
> + read_serial(dev, fn);
>
> rc = read_dvsec_tl(dev, fn);
> if (rc) {
> diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
> index 6f7c02f0d5e3..9843051c3c5b 100644
> --- a/include/misc/ocxl.h
> +++ b/include/misc/ocxl.h
> @@ -46,6 +46,7 @@ struct ocxl_fn_config {
> int dvsec_afu_info_pos; /* offset of the AFU information DVSEC */
> s8 max_pasid_log;
> s8 max_afu_index;
> + u64 serial;
> };
>
> enum ocxl_endian {