/*
   * Remote Processor Framework
   *
   * Copyright(c) 2011 Texas Instruments, Inc.
   * Copyright(c) 2011 Google, Inc.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * * Redistributions of source code must retain the above copyright
   *   notice, this list of conditions and the following disclaimer.
   * * Redistributions in binary form must reproduce the above copyright
   *   notice, this list of conditions and the following disclaimer in
   *   the documentation and/or other materials provided with the
   *   distribution.
   * * Neither the name Texas Instruments nor the names of its
   *   contributors may be used to endorse or promote products derived
   *   from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef REMOTEPROC_H
  #define REMOTEPROC_H
  
  #include <linux/types.h>
  #include <linux/klist.h>
  #include <linux/mutex.h>
  #include <linux/virtio.h>
  #include <linux/completion.h>
  #include <linux/idr.h>
  
  /**
   * struct resource_table - firmware resource table header
   * @ver: version number
   * @num: number of resource entries
   * @reserved: reserved (must be zero)
   * @offset: array of offsets pointing at the various resource entries
   *
   * A resource table is essentially a list of system resources required
   * by the remote processor. It may also include configuration entries.
   * If needed, the remote processor firmware should contain this table
   * as a dedicated ".resource_table" ELF section.
   *
   * Some resources entries are mere announcements, where the host is informed
   * of specific remoteproc configuration. Other entries require the host to
   * do something (e.g. allocate a system resource). Sometimes a negotiation
   * is expected, where the firmware requests a resource, and once allocated,
   * the host should provide back its details (e.g. address of an allocated
   * memory region).
   *
   * The header of the resource table, as expressed by this structure,
   * contains a version number (should we need to change this format in the
   * future), the number of available resource entries, and their offsets
   * in the table.
   *
   * Immediately following this header are the resource entries themselves,
   * each of which begins with a resource entry header (as described below).
   */
  struct resource_table {
  	u32 ver;
  	u32 num;
  	u32 reserved[2];
  	u32 offset[0];
  } __packed;
  
  /**
   * struct fw_rsc_hdr - firmware resource entry header
   * @type: resource type
   * @data: resource data
   *
   * Every resource entry begins with a 'struct fw_rsc_hdr' header providing
   * its @type. The content of the entry itself will immediately follow
   * this header, and it should be parsed according to the resource type.
   */
  struct fw_rsc_hdr {
  	u32 type;
  	u8 data[0];
  } __packed;
  
  /**
   * enum fw_resource_type - types of resource entries
   *
   * @RSC_CARVEOUT:   request for allocation of a physically contiguous
   *		    memory region.
   * @RSC_DEVMEM:     request to iommu_map a memory-based peripheral.
   * @RSC_TRACE:	    announces the availability of a trace buffer into which
   *		    the remote processor will be writing logs.
   * @RSC_VDEV:       declare support for a virtio device, and serve as its
   *		    virtio header.
   * @RSC_LAST:       just keep this one at the end
   *
   * For more details regarding a specific resource type, please see its
   * dedicated structure below.
   *
   * Please note that these values are used as indices to the rproc_handle_rsc
   * lookup table, so please keep them sane. Moreover, @RSC_LAST is used to
   * check the validity of an index before the lookup table is accessed, so
   * please update it as needed.
   */
  enum fw_resource_type {
  	RSC_CARVEOUT	= 0,
  	RSC_DEVMEM	= 1,
  	RSC_TRACE	= 2,
  	RSC_VDEV	= 3,
  	RSC_LAST	= 4,
  };
  
  #define FW_RSC_ADDR_ANY (0xFFFFFFFFFFFFFFFF)
  
  /**
   * struct fw_rsc_carveout - physically contiguous memory request
   * @da: device address
   * @pa: physical address
   * @len: length (in bytes)
   * @flags: iommu protection flags
   * @reserved: reserved (must be zero)
   * @name: human-readable name of the requested memory region
   *
   * This resource entry requests the host to allocate a physically contiguous
   * memory region.
   *
   * These request entries should precede other firmware resource entries,
   * as other entries might request placing other data objects inside
   * these memory regions (e.g. data/code segments, trace resource entries, ...).
   *
   * Allocating memory this way helps utilizing the reserved physical memory
   * (e.g. CMA) more efficiently, and also minimizes the number of TLB entries
   * needed to map it (in case @rproc is using an IOMMU). Reducing the TLB
   * pressure is important; it may have a substantial impact on performance.
   *
   * If the firmware is compiled with static addresses, then @da should specify
   * the expected device address of this memory region. If @da is set to
   * FW_RSC_ADDR_ANY, then the host will dynamically allocate it, and then
   * overwrite @da with the dynamically allocated address.
   *
   * We will always use @da to negotiate the device addresses, even if it
   * isn't using an iommu. In that case, though, it will obviously contain
   * physical addresses.
   *
   * Some remote processors needs to know the allocated physical address
   * even if they do use an iommu. This is needed, e.g., if they control
   * hardware accelerators which access the physical memory directly (this
   * is the case with OMAP4 for instance). In that case, the host will
   * overwrite @pa with the dynamically allocated physical address.
   * Generally we don't want to expose physical addresses if we don't have to
   * (remote processors are generally _not_ trusted), so we might want to
   * change this to happen _only_ when explicitly required by the hardware.
   *
   * @flags is used to provide IOMMU protection flags, and @name should
   * (optionally) contain a human readable name of this carveout region
   * (mainly for debugging purposes).
   */
  struct fw_rsc_carveout {
  	u32 da;
  	u32 pa;
  	u32 len;
  	u32 flags;
  	u32 reserved;
  	u8 name[32];
  } __packed;
  
  /**
   * struct fw_rsc_devmem - iommu mapping request
   * @da: device address
   * @pa: physical address
   * @len: length (in bytes)
   * @flags: iommu protection flags
   * @reserved: reserved (must be zero)
   * @name: human-readable name of the requested region to be mapped
   *
   * This resource entry requests the host to iommu map a physically contiguous
   * memory region. This is needed in case the remote processor requires
   * access to certain memory-based peripherals; _never_ use it to access
   * regular memory.
   *
   * This is obviously only needed if the remote processor is accessing memory
   * via an iommu.
   *
   * @da should specify the required device address, @pa should specify
   * the physical address we want to map, @len should specify the size of
   * the mapping and @flags is the IOMMU protection flags. As always, @name may
   * (optionally) contain a human readable name of this mapping (mainly for
   * debugging purposes).
   *
   * Note: at this point we just "trust" those devmem entries to contain valid
   * physical addresses, but this isn't safe and will be changed: eventually we
   * want remoteproc implementations to provide us ranges of physical addresses
   * the firmware is allowed to request, and not allow firmwares to request
   * access to physical addresses that are outside those ranges.
   */
  struct fw_rsc_devmem {
  	u32 da;
  	u32 pa;
  	u32 len;
  	u32 flags;
  	u32 reserved;
  	u8 name[32];
  } __packed;
  
  /**
   * struct fw_rsc_trace - trace buffer declaration
   * @da: device address
   * @len: length (in bytes)
   * @reserved: reserved (must be zero)
   * @name: human-readable name of the trace buffer
   *
   * This resource entry provides the host information about a trace buffer
   * into which the remote processor will write log messages.
   *
   * @da specifies the device address of the buffer, @len specifies
   * its size, and @name may contain a human readable name of the trace buffer.
   *
   * After booting the remote processor, the trace buffers are exposed to the
   * user via debugfs entries (called trace0, trace1, etc..).
   */
  struct fw_rsc_trace {
  	u32 da;
  	u32 len;
  	u32 reserved;
  	u8 name[32];
  } __packed;
  
  /**
   * struct fw_rsc_vdev_vring - vring descriptor entry
   * @da: device address
   * @align: the alignment between the consumer and producer parts of the vring
   * @num: num of buffers supported by this vring (must be power of two)
   * @notifyid is a unique rproc-wide notify index for this vring. This notify
   * index is used when kicking a remote processor, to let it know that this
   * vring is triggered.
   * @reserved: reserved (must be zero)
   *
   * This descriptor is not a resource entry by itself; it is part of the
   * vdev resource type (see below).
   *
   * Note that @da should either contain the device address where
   * the remote processor is expecting the vring, or indicate that
   * dynamically allocation of the vring's device address is supported.
   */
  struct fw_rsc_vdev_vring {
  	u32 da;
  	u32 align;
  	u32 num;
  	u32 notifyid;
  	u32 reserved;
  } __packed;
  
  /**
   * struct fw_rsc_vdev - virtio device header
   * @id: virtio device id (as in virtio_ids.h)
   * @notifyid is a unique rproc-wide notify index for this vdev. This notify
   * index is used when kicking a remote processor, to let it know that the
   * status/features of this vdev have changes.
   * @dfeatures specifies the virtio device features supported by the firmware
   * @gfeatures is a place holder used by the host to write back the
   * negotiated features that are supported by both sides.
   * @config_len is the size of the virtio config space of this vdev. The config
   * space lies in the resource table immediate after this vdev header.
   * @status is a place holder where the host will indicate its virtio progress.
   * @num_of_vrings indicates how many vrings are described in this vdev header
   * @reserved: reserved (must be zero)
   * @vring is an array of @num_of_vrings entries of 'struct fw_rsc_vdev_vring'.
   *
   * This resource is a virtio device header: it provides information about
   * the vdev, and is then used by the host and its peer remote processors
   * to negotiate and share certain virtio properties.
   *
   * By providing this resource entry, the firmware essentially asks remoteproc
   * to statically allocate a vdev upon registration of the rproc (dynamic vdev
   * allocation is not yet supported).
   *
   * Note: unlike virtualization systems, the term 'host' here means
   * the Linux side which is running remoteproc to control the remote
   * processors. We use the name 'gfeatures' to comply with virtio's terms,
   * though there isn't really any virtualized guest OS here: it's the host
   * which is responsible for negotiating the final features.
   * Yeah, it's a bit confusing.
   *
   * Note: immediately following this structure is the virtio config space for
   * this vdev (which is specific to the vdev; for more info, read the virtio
   * spec). the size of the config space is specified by @config_len.
   */
  struct fw_rsc_vdev {
  	u32 id;
  	u32 notifyid;
  	u32 dfeatures;
  	u32 gfeatures;
  	u32 config_len;
  	u8 status;
  	u8 num_of_vrings;
  	u8 reserved[2];
  	struct fw_rsc_vdev_vring vring[0];
  } __packed;
  
  /**
   * struct rproc_mem_entry - memory entry descriptor
   * @va:	virtual address
   * @dma: dma address
   * @len: length, in bytes
   * @da: device address
   * @priv: associated data
   * @node: list node
   */
  struct rproc_mem_entry {
  	void *va;
  	dma_addr_t dma;
  	int len;
  	u32 da;
  	void *priv;
  	struct list_head node;
  };
  
  struct rproc;
  
  /**
   * struct rproc_ops - platform-specific device handlers
   * @start:	power on the device and boot it
   * @stop:	power off the device
   * @kick:	kick a virtqueue (virtqueue id given as a parameter)
   */
  struct rproc_ops {
  	int (*start)(struct rproc *rproc);
  	int (*stop)(struct rproc *rproc);
  	void (*kick)(struct rproc *rproc, int vqid);
  };
  
  /**
   * enum rproc_state - remote processor states
   * @RPROC_OFFLINE:	device is powered off
   * @RPROC_SUSPENDED:	device is suspended; needs to be woken up to receive
   *			a message.
   * @RPROC_RUNNING:	device is up and running
   * @RPROC_CRASHED:	device has crashed; need to start recovery
   * @RPROC_LAST:		just keep this one at the end
   *
   * Please note that the values of these states are used as indices
   * to rproc_state_string, a state-to-name lookup table,
   * so please keep the two synchronized. @RPROC_LAST is used to check
   * the validity of an index before the lookup table is accessed, so
   * please update it as needed too.
   */
  enum rproc_state {
  	RPROC_OFFLINE	= 0,
  	RPROC_SUSPENDED	= 1,
  	RPROC_RUNNING	= 2,
  	RPROC_CRASHED	= 3,
  	RPROC_LAST	= 4,
  };
  
  /**
   * enum rproc_crash_type - remote processor crash types
   * @RPROC_MMUFAULT:	iommu fault
   *
   * Each element of the enum is used as an array index. So that, the value of
   * the elements should be always something sane.
   *
   * Feel free to add more types when needed.
   */
  enum rproc_crash_type {
  	RPROC_MMUFAULT,
  };
  
  /**
   * struct rproc - represents a physical remote processor device
   * @node: klist node of this rproc object
   * @domain: iommu domain
   * @name: human readable name of the rproc
   * @firmware: name of firmware file to be loaded
   * @priv: private data which belongs to the platform-specific rproc module
   * @ops: platform-specific start/stop rproc handlers
   * @dev: virtual device for refcounting and common remoteproc behavior
   * @fw_ops: firmware-specific handlers
   * @power: refcount of users who need this rproc powered up
   * @state: state of the device
   * @lock: lock which protects concurrent manipulations of the rproc
   * @dbg_dir: debugfs directory of this rproc device
   * @traces: list of trace buffers
   * @num_traces: number of trace buffers
   * @carveouts: list of physically contiguous memory allocations
   * @mappings: list of iommu mappings we initiated, needed on shutdown
   * @firmware_loading_complete: marks e/o asynchronous firmware loading
   * @bootaddr: address of first instruction to boot rproc with (optional)
   * @rvdevs: list of remote virtio devices
   * @notifyids: idr for dynamically assigning rproc-wide unique notify ids
   * @index: index of this rproc device
   * @crash_handler: workqueue for handling a crash
   * @crash_cnt: crash counter
   * @crash_comp: completion used to sync crash handler and the rproc reload
   * @recovery_disabled: flag that state if recovery was disabled
   * @max_notifyid: largest allocated notify id.
   * @table_ptr: pointer to the resource table in effect
   * @cached_table: copy of the resource table
   * @table_csum: checksum of the resource table
   */
  struct rproc {
  	struct klist_node node;
  	struct iommu_domain *domain;
  	const char *name;
  	const char *firmware;
  	void *priv;
  	const struct rproc_ops *ops;
  	struct device dev;
  	const struct rproc_fw_ops *fw_ops;
  	atomic_t power;
  	unsigned int state;
  	struct mutex lock;
  	struct dentry *dbg_dir;
  	struct list_head traces;
  	int num_traces;
  	struct list_head carveouts;
  	struct list_head mappings;
  	struct completion firmware_loading_complete;
  	u32 bootaddr;
  	struct list_head rvdevs;
  	struct idr notifyids;
  	int index;
  	struct work_struct crash_handler;
  	unsigned crash_cnt;
  	struct completion crash_comp;
  	bool recovery_disabled;
  	int max_notifyid;
  	struct resource_table *table_ptr;
  	struct resource_table *cached_table;
  	u32 table_csum;
  };
  
  /* we currently support only two vrings per rvdev */
  
  #define RVDEV_NUM_VRINGS 2
  
  /**
   * struct rproc_vring - remoteproc vring state
   * @va:	virtual address
   * @dma: dma address
   * @len: length, in bytes
   * @da: device address
   * @align: vring alignment
   * @notifyid: rproc-specific unique vring index
   * @rvdev: remote vdev
   * @vq: the virtqueue of this vring
   */
  struct rproc_vring {
  	void *va;
  	dma_addr_t dma;
  	int len;
  	u32 da;
  	u32 align;
  	int notifyid;
  	struct rproc_vdev *rvdev;
  	struct virtqueue *vq;
  };
  
  /**
   * struct rproc_vdev - remoteproc state for a supported virtio device
   * @node: list node
   * @rproc: the rproc handle
   * @vdev: the virio device
   * @vring: the vrings for this vdev
   * @rsc_offset: offset of the vdev's resource entry
   */
  struct rproc_vdev {
  	struct list_head node;
  	struct rproc *rproc;
  	struct virtio_device vdev;
  	struct rproc_vring vring[RVDEV_NUM_VRINGS];
  	u32 rsc_offset;
  };
  
  struct rproc *rproc_alloc(struct device *dev, const char *name,
  				const struct rproc_ops *ops,
  				const char *firmware, int len);
  void rproc_put(struct rproc *rproc);
  int rproc_add(struct rproc *rproc);
  int rproc_del(struct rproc *rproc);
  
  int rproc_boot(struct rproc *rproc);
  void rproc_shutdown(struct rproc *rproc);
  void rproc_report_crash(struct rproc *rproc, enum rproc_crash_type type);
  
  static inline struct rproc_vdev *vdev_to_rvdev(struct virtio_device *vdev)
  {
  	return container_of(vdev, struct rproc_vdev, vdev);
  }
  
  static inline struct rproc *vdev_to_rproc(struct virtio_device *vdev)
  {
  	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
  
  	return rvdev->rproc;
  }
  
  #endif /* REMOTEPROC_H */