/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright 2020-2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 */

#ifndef _NE_PCI_DEV_H_
#define _NE_PCI_DEV_H_

#include <linux/atomic.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/pci_ids.h>
#include <linux/wait.h>

/**
 * DOC: Nitro Enclaves (NE) PCI device
 */

/**
 * PCI_DEVICE_ID_NE - Nitro Enclaves PCI device id.
 */
#define PCI_DEVICE_ID_NE	(0xe4c1)
/**
 * PCI_BAR_NE - Nitro Enclaves PCI device MMIO BAR.
 */
#define PCI_BAR_NE		(0x03)

/**
 * DOC: Device registers in the NE PCI device MMIO BAR
 */

/**
 * NE_ENABLE - (1 byte) Register to notify the device that the driver is using
 *	       it (Read/Write).
 */
#define NE_ENABLE		(0x0000)
#define NE_ENABLE_OFF		(0x00)
#define NE_ENABLE_ON		(0x01)

/**
 * NE_VERSION - (2 bytes) Register to select the device run-time version
 *		(Read/Write).
 */
#define NE_VERSION		(0x0002)
#define NE_VERSION_MAX		(0x0001)

/**
 * NE_COMMAND - (4 bytes) Register to notify the device what command was
 *		requested (Write-Only).
 */
#define NE_COMMAND		(0x0004)

/**
 * NE_EVTCNT - (4 bytes) Register to notify the driver that a reply or a device
 *	       event is available (Read-Only):
 *	       - Lower half  - command reply counter
 *	       - Higher half - out-of-band device event counter
 */
#define NE_EVTCNT		(0x000c)
#define NE_EVTCNT_REPLY_SHIFT	(0)
#define NE_EVTCNT_REPLY_MASK	(0x0000ffff)
#define NE_EVTCNT_REPLY(cnt)	(((cnt) & NE_EVTCNT_REPLY_MASK) >> \
				NE_EVTCNT_REPLY_SHIFT)
#define NE_EVTCNT_EVENT_SHIFT	(16)
#define NE_EVTCNT_EVENT_MASK	(0xffff0000)
#define NE_EVTCNT_EVENT(cnt)	(((cnt) & NE_EVTCNT_EVENT_MASK) >> \
				NE_EVTCNT_EVENT_SHIFT)

/**
 * NE_SEND_DATA - (240 bytes) Buffer for sending the command request payload
 *		  (Read/Write).
 */
#define NE_SEND_DATA		(0x0010)

/**
 * NE_RECV_DATA - (240 bytes) Buffer for receiving the command reply payload
 *		  (Read-Only).
 */
#define NE_RECV_DATA		(0x0100)

/**
 * DOC: Device MMIO buffer sizes
 */

/**
 * NE_SEND_DATA_SIZE - Size of the send buffer, in bytes.
 */
#define NE_SEND_DATA_SIZE	(240)

/**
 * NE_RECV_DATA_SIZE - Size of the receive buffer, in bytes.
 */
#define NE_RECV_DATA_SIZE	(240)

/**
 * DOC: MSI-X interrupt vectors
 */

/**
 * NE_VEC_REPLY - MSI-X vector used for command reply notification.
 */
#define NE_VEC_REPLY		(0)

/**
 * NE_VEC_EVENT - MSI-X vector used for out-of-band events e.g. enclave crash.
 */
#define NE_VEC_EVENT		(1)

/**
 * enum ne_pci_dev_cmd_type - Device command types.
 * @INVALID_CMD:		Invalid command.
 * @ENCLAVE_START:		Start an enclave, after setting its resources.
 * @ENCLAVE_GET_SLOT:		Get the slot uid of an enclave.
 * @ENCLAVE_STOP:		Terminate an enclave.
 * @SLOT_ALLOC :		Allocate a slot for an enclave.
 * @SLOT_FREE:			Free the slot allocated for an enclave
 * @SLOT_ADD_MEM:		Add a memory region to an enclave slot.
 * @SLOT_ADD_VCPU:		Add a vCPU to an enclave slot.
 * @SLOT_COUNT :		Get the number of allocated slots.
 * @NEXT_SLOT:			Get the next slot in the list of allocated slots.
 * @SLOT_INFO:			Get the info for a slot e.g. slot uid, vCPUs count.
 * @SLOT_ADD_BULK_VCPUS:	Add a number of vCPUs, not providing CPU ids.
 * @MAX_CMD:			A gatekeeper for max possible command type.
 */
enum ne_pci_dev_cmd_type {
	INVALID_CMD		= 0,
	ENCLAVE_START		= 1,
	ENCLAVE_GET_SLOT	= 2,
	ENCLAVE_STOP		= 3,
	SLOT_ALLOC		= 4,
	SLOT_FREE		= 5,
	SLOT_ADD_MEM		= 6,
	SLOT_ADD_VCPU		= 7,
	SLOT_COUNT		= 8,
	NEXT_SLOT		= 9,
	SLOT_INFO		= 10,
	SLOT_ADD_BULK_VCPUS	= 11,
	MAX_CMD,
};

/**
 * DOC: Device commands - payload structure for requests and replies.
 */

/**
 * struct enclave_start_req - ENCLAVE_START request.
 * @slot_uid:		Slot unique id mapped to the enclave to start.
 * @enclave_cid:	Context ID (CID) for the enclave vsock device.
 *			If 0, CID is autogenerated.
 * @flags:		Flags for the enclave to start with (e.g. debug mode).
 */
struct enclave_start_req {
	u64	slot_uid;
	u64	enclave_cid;
	u64	flags;
};

/**
 * struct enclave_get_slot_req - ENCLAVE_GET_SLOT request.
 * @enclave_cid:	Context ID (CID) for the enclave vsock device.
 */
struct enclave_get_slot_req {
	u64	enclave_cid;
};

/**
 * struct enclave_stop_req - ENCLAVE_STOP request.
 * @slot_uid:	Slot unique id mapped to the enclave to stop.
 */
struct enclave_stop_req {
	u64	slot_uid;
};

/**
 * struct slot_alloc_req - SLOT_ALLOC request.
 * @unused:	In order to avoid weird sizeof edge cases.
 */
struct slot_alloc_req {
	u8	unused;
};

/**
 * struct slot_free_req - SLOT_FREE request.
 * @slot_uid:	Slot unique id mapped to the slot to free.
 */
struct slot_free_req {
	u64	slot_uid;
};

/* TODO: Add flags field to the request to add memory region. */
/**
 * struct slot_add_mem_req - SLOT_ADD_MEM request.
 * @slot_uid:	Slot unique id mapped to the slot to add the memory region to.
 * @paddr:	Physical address of the memory region to add to the slot.
 * @size:	Memory size, in bytes, of the memory region to add to the slot.
 */
struct slot_add_mem_req {
	u64	slot_uid;
	u64	paddr;
	u64	size;
};

/**
 * struct slot_add_vcpu_req - SLOT_ADD_VCPU request.
 * @slot_uid:	Slot unique id mapped to the slot to add the vCPU to.
 * @vcpu_id:	vCPU ID of the CPU to add to the enclave.
 * @padding:	Padding for the overall data structure.
 */
struct slot_add_vcpu_req {
	u64	slot_uid;
	u32	vcpu_id;
	u8	padding[4];
};

/**
 * struct slot_count_req - SLOT_COUNT request.
 * @unused:	In order to avoid weird sizeof edge cases.
 */
struct slot_count_req {
	u8	unused;
};

/**
 * struct next_slot_req - NEXT_SLOT request.
 * @slot_uid:	Slot unique id of the next slot in the iteration.
 */
struct next_slot_req {
	u64	slot_uid;
};

/**
 * struct slot_info_req - SLOT_INFO request.
 * @slot_uid:	Slot unique id mapped to the slot to get information about.
 */
struct slot_info_req {
	u64	slot_uid;
};

/**
 * struct slot_add_bulk_vcpus_req - SLOT_ADD_BULK_VCPUS request.
 * @slot_uid:	Slot unique id mapped to the slot to add vCPUs to.
 * @nr_vcpus:	Number of vCPUs to add to the slot.
 */
struct slot_add_bulk_vcpus_req {
	u64	slot_uid;
	u64	nr_vcpus;
};

/**
 * struct ne_pci_dev_cmd_reply - NE PCI device command reply.
 * @rc :		Return code of the logic that processed the request.
 * @padding0:		Padding for the overall data structure.
 * @slot_uid:		Valid for all commands except SLOT_COUNT.
 * @enclave_cid:	Valid for ENCLAVE_START command.
 * @slot_count :	Valid for SLOT_COUNT command.
 * @mem_regions:	Valid for SLOT_ALLOC and SLOT_INFO commands.
 * @mem_size:		Valid for SLOT_INFO command.
 * @nr_vcpus:		Valid for SLOT_INFO command.
 * @flags:		Valid for SLOT_INFO command.
 * @state:		Valid for SLOT_INFO command.
 * @padding1:		Padding for the overall data structure.
 */
struct ne_pci_dev_cmd_reply {
	s32	rc;
	u8	padding0[4];
	u64	slot_uid;
	u64	enclave_cid;
	u64	slot_count;
	u64	mem_regions;
	u64	mem_size;
	u64	nr_vcpus;
	u64	flags;
	u16	state;
	u8	padding1[6];
};

/**
 * struct ne_pci_dev - Nitro Enclaves (NE) PCI device.
 * @cmd_reply_avail:		Variable set if a reply has been sent by the
 *				PCI device.
 * @cmd_reply_wait_q:		Wait queue for handling command reply from the
 *				PCI device.
 * @enclaves_list:		List of the enclaves managed by the PCI device.
 * @enclaves_list_mutex:	Mutex for accessing the list of enclaves.
 * @event_wq:			Work queue for handling out-of-band events
 *				triggered by the Nitro Hypervisor which require
 *				enclave state scanning and propagation to the
 *				enclave process.
 * @iomem_base :		MMIO region of the PCI device.
 * @notify_work:		Work item for every received out-of-band event.
 * @pci_dev_mutex:		Mutex for accessing the PCI device MMIO space.
 * @pdev:			PCI device data structure.
 */
struct ne_pci_dev {
	atomic_t		cmd_reply_avail;
	wait_queue_head_t	cmd_reply_wait_q;
	struct list_head	enclaves_list;
	struct mutex		enclaves_list_mutex;
	struct workqueue_struct	*event_wq;
	void __iomem		*iomem_base;
	struct work_struct	notify_work;
	struct mutex		pci_dev_mutex;
	struct pci_dev		*pdev;
};

/**
 * ne_do_request() - Submit command request to the PCI device based on the command
 *		     type and retrieve the associated reply.
 * @pdev:		PCI device to send the command to and receive the reply from.
 * @cmd_type:		Command type of the request sent to the PCI device.
 * @cmd_request:	Command request payload.
 * @cmd_request_size:	Size of the command request payload.
 * @cmd_reply:		Command reply payload.
 * @cmd_reply_size:	Size of the command reply payload.
 *
 * Context: Process context. This function uses the ne_pci_dev mutex to handle
 *	    one command at a time.
 * Return:
 * * 0 on success.
 * * Negative return value on failure.
 */
int ne_do_request(struct pci_dev *pdev, enum ne_pci_dev_cmd_type cmd_type,
		  void *cmd_request, size_t cmd_request_size,
		  struct ne_pci_dev_cmd_reply *cmd_reply,
		  size_t cmd_reply_size);

/* Nitro Enclaves (NE) PCI device driver */
extern struct pci_driver ne_pci_driver;

#endif /* _NE_PCI_DEV_H_ */