On Wed, Jan 26, 2022 at 07:50:39PM +0000, Lad Prabhakar wrote:
> Add flag to indicate if PCIe EP supports internal DMAC and also add a
> wrapper function which invokes dmac_transfer() callback which lands
> in the PCIe EP driver.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> ---
> drivers/pci/endpoint/pci-epf-core.c | 32 +++++++++++++++++++++++++++++
> include/linux/pci-epc.h | 8 ++++++++
> include/linux/pci-epf.h | 7 +++++++
> 3 files changed, 47 insertions(+)
>
> diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
> index 9ed556936f48..f70576d0d4b2 100644
> --- a/drivers/pci/endpoint/pci-epf-core.c
> +++ b/drivers/pci/endpoint/pci-epf-core.c
> @@ -239,6 +239,38 @@ void pci_epf_remove_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf)
> }
> EXPORT_SYMBOL_GPL(pci_epf_remove_vepf);
>
> +/**
> + * pci_epf_internal_dmac_xfr() - transfer data between EPC and remote PCIe RC
Transfer data between EP and host using internal DMA engine
> + * @epf: the EPF device that performs the data transfer operation
> + * @dma_dst: The destination address of the data transfer. It can be a physical
> + * address given by pci_epc_mem_alloc_addr or DMA mapping APIs.
> + * @dma_src: The source address of the data transfer. It can be a physical
> + * address given by pci_epc_mem_alloc_addr or DMA mapping APIs.
> + * @len: The size of the data transfer
> + *
> + * Invoke to transfer data between EPC and remote PCIe RC using internal dmac.
> + */
> +int pci_epf_internal_dmac_xfr(struct pci_epf *epf, dma_addr_t dma_dst,
> + dma_addr_t dma_src, size_t len,
> + enum pci_epf_xfr_direction dir)
How about "pci_epf_internal_dma_xfer"? I think DMAC is somewhat platform
specific so we could just use DMA. And "xfer" is being used more commonly for
"transfer".
> +{
> + struct pci_epc *epc = epf->epc;
> + int ret;
> +
> + if (IS_ERR_OR_NULL(epc) || IS_ERR_OR_NULL(epf))
> + return -EINVAL;
> +
> + if (!epc->ops->dmac_transfer)
> + return -EINVAL;
> +
> + mutex_lock(&epf->lock);
> + ret = epc->ops->dmac_transfer(epc, epf, dma_dst, dma_src, len, dir);
internal_dma_xfer? It doesn't look perfect but I can't think of any other way to
represent it as an internal dma callback.
> + mutex_unlock(&epf->lock);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(pci_epf_internal_dmac_xfr);
> +
> /**
> * pci_epf_free_space() - free the allocated PCI EPF register space
> * @epf: the EPF device from whom to free the memory
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index a48778e1a4ee..b55dacd09e1e 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -58,6 +58,7 @@ pci_epc_interface_string(enum pci_epc_interface_type type)
> * @map_msi_irq: ops to map physical address to MSI address and return MSI data
> * @start: ops to start the PCI link
> * @stop: ops to stop the PCI link
> + * @dmac_transfer: ops to transfer data using internal DMAC
> * @get_features: ops to get the features supported by the EPC
> * @owner: the module owner containing the ops
> */
> @@ -86,6 +87,9 @@ struct pci_epc_ops {
> u32 *msi_addr_offset);
> int (*start)(struct pci_epc *epc);
> void (*stop)(struct pci_epc *epc);
> + int (*dmac_transfer)(struct pci_epc *epc, struct pci_epf *epf,
> + dma_addr_t dma_dst, dma_addr_t dma_src,
> + size_t len, enum pci_epf_xfr_direction dir);
> const struct pci_epc_features* (*get_features)(struct pci_epc *epc,
> u8 func_no, u8 vfunc_no);
> struct module *owner;
> @@ -159,6 +163,8 @@ struct pci_epc {
> * for initialization
> * @msi_capable: indicate if the endpoint function has MSI capability
> * @msix_capable: indicate if the endpoint function has MSI-X capability
> + * @internal_dmac: indicate if the endpoint function has internal DMAC
> + * @internal_dmac_mask: indicates the DMA mask to be applied for the device
> * @reserved_bar: bitmap to indicate reserved BAR unavailable to function driver
> * @bar_fixed_64bit: bitmap to indicate fixed 64bit BARs
> * @bar_fixed_size: Array specifying the size supported by each BAR
> @@ -169,6 +175,8 @@ struct pci_epc_features {
> unsigned int core_init_notifier : 1;
> unsigned int msi_capable : 1;
> unsigned int msix_capable : 1;
> + unsigned int internal_dmac : 1;
> + u64 internal_dmac_mask;
internal_dma?
> u8 reserved_bar;
> u8 bar_fixed_64bit;
> u64 bar_fixed_size[PCI_STD_NUM_BARS];
> diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
> index 009a07147c61..78d661db085d 100644
> --- a/include/linux/pci-epf.h
> +++ b/include/linux/pci-epf.h
> @@ -32,6 +32,11 @@ enum pci_barno {
> BAR_5,
> };
>
> +enum pci_epf_xfr_direction {
> + PCIE_TO_INTERNAL,
> + INTERNAL_TO_PCIE,
I think we could just use "dma_data_direction" as we are anyway transferring
data between host and device.
Thanks,
Mani
> +};
> +
> /**
> * struct pci_epf_header - represents standard configuration header
> * @vendorid: identifies device manufacturer
> @@ -209,6 +214,8 @@ void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar,
> enum pci_epc_interface_type type);
> int pci_epf_bind(struct pci_epf *epf);
> void pci_epf_unbind(struct pci_epf *epf);
> +int pci_epf_internal_dmac_xfr(struct pci_epf *epf, dma_addr_t dma_dst, dma_addr_t dma_src,
> + size_t len, enum pci_epf_xfr_direction dir);
> struct config_group *pci_epf_type_add_cfs(struct pci_epf *epf,
> struct config_group *group);
> int pci_epf_add_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf);
> --
> 2.25.1
>
