On Mon, Feb 11, 2019 at 01:50:31PM -0800, sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
>
> Return the PRG Response PASID Required bit in the Page Request
> Status Register.
>
> As per PCIe spec r4.0, sec 10.5.2.3, if this bit is Set then the device
> expects a PASID TLP Prefix on PRG Response Messages when the
> corresponding Page Requests had a PASID TLP Prefix. If Clear, the device
> does not expect PASID TLP Prefixes on any PRG Response Message, and the
> device behavior is undefined if this bit is Clear and the device
> receives a PRG Response Message with a PASID TLP Prefix. Also the device
> behavior is undefined in the this bit is Set and the device receives a
> PRG Response Message with no PASID TLP Prefix when the corresponding
> Page Requests had a PASID TLP Prefix.
s/Set then the device/Set, the device/
s/undefined if this bit is Clear and the device/undefined if the device/
s/is undefined in the this/is undefined if this/
> This function will be used by drivers like IOMMU, if it is required to
> check the status of the PRG Response PASID Required bit before enabling
> the PASID support of the device.
>
> Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Cc: Keith Busch <keith.busch@xxxxxxxxx>
> Suggested-by: Ashok Raj <ashok.raj@xxxxxxxxx>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
With typos (also below) addressed,
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> ---
> drivers/pci/ats.c | 31 +++++++++++++++++++++++++++++++
> include/linux/pci-ats.h | 5 +++++
> include/uapi/linux/pci_regs.h | 1 +
> 3 files changed, 37 insertions(+)
>
> diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
> index 5b78f3b1b918..f843cd846dff 100644
> --- a/drivers/pci/ats.c
> +++ b/drivers/pci/ats.c
> @@ -368,6 +368,37 @@ int pci_pasid_features(struct pci_dev *pdev)
> }
> EXPORT_SYMBOL_GPL(pci_pasid_features);
>
> +/**
> + * pci_prg_resp_pasid_required - Return PRG Response PASID Required bit
> + * status.
> + * @pdev: PCI device structure
> + *
> + * Returns 1 if PASID is required in PRG Response message, 0 otherwise.
> + *
> + * Even though the PRG response PASID status is read from PRI status
> + * register, since this API will mainly be used by PASID users, this
> + * function is defined within #ifdef CONFIG_PCI_PASID instead of
> + * CONFIG_PCI_PRI.
> + *
Remove blank comment line.
> + */
> +int pci_prg_resp_pasid_required(struct pci_dev *pdev)
> +{
> + u16 status;
> + int pos;
> +
> + pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI);
> + if (!pos)
> + return 0;
> +
> + pci_read_config_word(pdev, pos + PCI_PRI_STATUS, &status);
> +
> + if (status & PCI_PRI_STATUS_PASID)
> + return 1;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_prg_resp_pasid_required);
> +
> #define PASID_NUMBER_SHIFT 8
> #define PASID_NUMBER_MASK (0x1f << PASID_NUMBER_SHIFT)
> /**
> diff --git a/include/linux/pci-ats.h b/include/linux/pci-ats.h
> index 7c4b8e27268c..facfd6a18fe1 100644
> --- a/include/linux/pci-ats.h
> +++ b/include/linux/pci-ats.h
> @@ -40,6 +40,7 @@ void pci_disable_pasid(struct pci_dev *pdev);
> void pci_restore_pasid_state(struct pci_dev *pdev);
> int pci_pasid_features(struct pci_dev *pdev);
> int pci_max_pasids(struct pci_dev *pdev);
> +int pci_prg_resp_pasid_required(struct pci_dev *pdev);
>
> #else /* CONFIG_PCI_PASID */
>
> @@ -66,6 +67,10 @@ static inline int pci_max_pasids(struct pci_dev *pdev)
> return -EINVAL;
> }
>
> +static int pci_prg_resp_pasid_required(struct pci_dev *pdev)
> +{
> + return 0;
> +}
> #endif /* CONFIG_PCI_PASID */
>
>
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index e1e9888c85e6..898be572b010 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -880,6 +880,7 @@
> #define PCI_PRI_STATUS_RF 0x001 /* Response Failure */
> #define PCI_PRI_STATUS_UPRGI 0x002 /* Unexpected PRG index */
> #define PCI_PRI_STATUS_STOPPED 0x100 /* PRI Stopped */
> +#define PCI_PRI_STATUS_PASID 0x8000 /* PRG Response PASID Required */
> #define PCI_PRI_MAX_REQ 0x08 /* PRI max reqs supported */
> #define PCI_PRI_ALLOC_REQ 0x0c /* PRI max reqs allowed */
> #define PCI_EXT_CAP_PRI_SIZEOF 16
> --
> 2.20.1
>
