On 7/20/2022 4:52 AM, ira.weiny@xxxxxxxxx wrote:
> From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
>
> Introduced in a PCIe r6.0, sec 6.30, DOE provides a config space based
> mailbox with standard protocol discovery. Each mailbox is accessed
> through a DOE Extended Capability.
>
> Each DOE mailbox must support the DOE discovery protocol in addition to
> any number of additional protocols.
>
> Define core PCIe functionality to manage a single PCIe DOE mailbox at a
> defined config space offset. Functionality includes iterating,
> creating, query of supported protocol, and task submission. Destruction
> of the mailboxes is device managed.
>
> Cc: "Li, Ming" <ming4.li@xxxxxxxxx>
> Cc: Bjorn Helgaas <helgaas@xxxxxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Acked-by: Bjorn Helgaas <helgaas@xxxxxxxxxx>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> Co-developed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
>
> ---
> +/**
> + * pci_doe_submit_task() - Submit a task to be processed by the state machine
> + *
> + * @doe_mb: DOE mailbox capability to submit to
> + * @task: task to be queued
> + *
> + * Submit a DOE task (request/response) to the DOE mailbox to be processed.
> + * Returns upon queueing the task object. If the queue is full this function
> + * will sleep until there is room in the queue.
> + *
> + * task->complete will be called when the state machine is done processing this
> + * task.
> + *
> + * Excess data will be discarded.
> + *
> + * RETURNS: 0 when task has been successfully queued, -ERRNO on error
> + */
> +int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task)
> +{
> + if (!pci_doe_supports_prot(doe_mb, task->prot.vid, task->prot.type))
> + return -EINVAL;
> +
> + /*
> + * DOE requests must be a whole number of DW and the response needs to
> + * be big enough for at least 1 DW
> + */
> + if (task->request_pl_sz % sizeof(u32) ||
> + task->response_pl_sz < sizeof(u32))
> + return -EINVAL;
> +
> + if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags))
> + return -EIO;
> +
> + task->doe_mb = doe_mb;
> + INIT_WORK(&task->work, doe_statemachine_work);
> + queue_work(doe_mb->work_queue, &task->work);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(pci_doe_submit_task);
I'm curious why there is not a sychronous function for DOE users. I think some protocols over DOE need a DOE sychrounous interface(e.g. SPDM, TDISP, IDE...). These protocols have to implement an sychronous function over pci_doe_submit_task() by themselves, maybe we can implement an generic sychronous function in PCI/DOE for these DOE users.
Thanks
Ming
> diff --git a/include/linux/pci-doe.h b/include/linux/pci-doe.h
> new file mode 100644
> index 000000000000..ed9b4df792b8
> --- /dev/null
> +++ b/include/linux/pci-doe.h
> @@ -0,0 +1,77 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Data Object Exchange
> + * PCIe r6.0, sec 6.30 DOE
> + *
> + * Copyright (C) 2021 Huawei
> + * Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> + *
> + * Copyright (C) 2022 Intel Corporation
> + * Ira Weiny <ira.weiny@xxxxxxxxx>
> + */
> +
> +#ifndef LINUX_PCI_DOE_H
> +#define LINUX_PCI_DOE_H
> +
> +struct pci_doe_protocol {
> + u16 vid;
> + u8 type;
> +};
> +
> +struct pci_doe_mb;
> +
> +/**
> + * struct pci_doe_task - represents a single query/response
> + *
> + * @prot: DOE Protocol
> + * @request_pl: The request payload
> + * @request_pl_sz: Size of the request payload (bytes)
> + * @response_pl: The response payload
> + * @response_pl_sz: Size of the response payload (bytes)
> + * @rv: Return value. Length of received response or error (bytes)
> + * @complete: Called when task is complete
> + * @private: Private data for the consumer
> + * @work: Used internally by the mailbox
> + * @doe_mb: Used internally by the mailbox
> + *
> + * The payload sizes and rv are specified in bytes with the following
> + * restrictions concerning the protocol.
> + *
> + * 1) The request_pl_sz must be a multiple of double words (4 bytes)
> + * 2) The response_pl_sz must be >= a single double word (4 bytes)
> + * 3) rv is returned as bytes but it will be a multiple of double words
> + *
> + * NOTE there is no need for the caller to initialize work or doe_mb.
> + */
> +struct pci_doe_task {
> + struct pci_doe_protocol prot;
> + u32 *request_pl;
> + size_t request_pl_sz;
> + u32 *response_pl;
> + size_t response_pl_sz;
> + int rv;
> + void (*complete)(struct pci_doe_task *task);
> + void *private;
> +
> + /* No need for the user to initialize these fields */
> + struct work_struct work;
> + struct pci_doe_mb *doe_mb;
> +};
> +
> +/**
> + * pci_doe_for_each_off - Iterate each DOE capability
> + * @pdev: struct pci_dev to iterate
> + * @off: u16 of config space offset of each mailbox capability found
> + */
> +#define pci_doe_for_each_off(pdev, off) \
> + for (off = pci_find_next_ext_capability(pdev, off, \
> + PCI_EXT_CAP_ID_DOE); \
> + off > 0; \
> + off = pci_find_next_ext_capability(pdev, off, \
> + PCI_EXT_CAP_ID_DOE))
> +
> +struct pci_doe_mb *pcim_doe_create_mb(struct pci_dev *pdev, u16 cap_offset);
> +bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type);
> +int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task);
> +
> +#endif
> diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> index 108f8523fa04..57b8e2ffb1dd 100644
> --- a/include/uapi/linux/pci_regs.h
> +++ b/include/uapi/linux/pci_regs.h
> @@ -737,7 +737,8 @@
> #define PCI_EXT_CAP_ID_DVSEC 0x23 /* Designated Vendor-Specific */
> #define PCI_EXT_CAP_ID_DLF 0x25 /* Data Link Feature */
> #define PCI_EXT_CAP_ID_PL_16GT 0x26 /* Physical Layer 16.0 GT/s */
> -#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_PL_16GT
> +#define PCI_EXT_CAP_ID_DOE 0x2E /* Data Object Exchange */
> +#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_DOE
>
> #define PCI_EXT_CAP_DSN_SIZEOF 12
> #define PCI_EXT_CAP_MCAST_ENDPOINT_SIZEOF 40
> @@ -1103,4 +1104,30 @@
> #define PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK 0x000000F0
> #define PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT 4
>
> +/* Data Object Exchange */
> +#define PCI_DOE_CAP 0x04 /* DOE Capabilities Register */
> +#define PCI_DOE_CAP_INT_SUP 0x00000001 /* Interrupt Support */
> +#define PCI_DOE_CAP_INT_MSG_NUM 0x00000ffe /* Interrupt Message Number */
> +#define PCI_DOE_CTRL 0x08 /* DOE Control Register */
> +#define PCI_DOE_CTRL_ABORT 0x00000001 /* DOE Abort */
> +#define PCI_DOE_CTRL_INT_EN 0x00000002 /* DOE Interrupt Enable */
> +#define PCI_DOE_CTRL_GO 0x80000000 /* DOE Go */
> +#define PCI_DOE_STATUS 0x0c /* DOE Status Register */
> +#define PCI_DOE_STATUS_BUSY 0x00000001 /* DOE Busy */
> +#define PCI_DOE_STATUS_INT_STATUS 0x00000002 /* DOE Interrupt Status */
> +#define PCI_DOE_STATUS_ERROR 0x00000004 /* DOE Error */
> +#define PCI_DOE_STATUS_DATA_OBJECT_READY 0x80000000 /* Data Object Ready */
> +#define PCI_DOE_WRITE 0x10 /* DOE Write Data Mailbox Register */
> +#define PCI_DOE_READ 0x14 /* DOE Read Data Mailbox Register */
> +
> +/* DOE Data Object - note not actually registers */
> +#define PCI_DOE_DATA_OBJECT_HEADER_1_VID 0x0000ffff
> +#define PCI_DOE_DATA_OBJECT_HEADER_1_TYPE 0x00ff0000
> +#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_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
> +
> #endif /* LINUX_PCI_REGS_H */
