/*
 * Copyright (c) 2015-2016, Linaro Limited
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#ifndef __TEE_DRV_H
#define __TEE_DRV_H

#include <linux/types.h>
#include <linux/idr.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/tee.h>

/*
 * The file describes the API provided by the generic TEE driver to the
 * specific TEE driver.
 */

#define TEE_SHM_MAPPED          BIT(0)  /* Memory mapped by the kernel */
#define TEE_SHM_DMA_BUF         BIT(1)  /* Memory with dma-buf handle */
#define TEE_SHM_EXT_DMA_BUF     BIT(2)  /* Memory with dma-buf handle */
#define TEE_SHM_REGISTER        BIT(3)  /* Memory registered in secure world */
#define TEE_SHM_USER_MAPPED     BIT(4)  /* Memory mapped in user space */
#define TEE_SHM_POOL            BIT(5)  /* Memory allocated from pool */

struct device;
struct tee_device;
struct tee_shm;
struct tee_shm_pool;

/**
 * struct tee_context - driver specific context on file pointer data
 * @teedev:     pointer to this drivers struct tee_device
 * @list_shm:   List of shared memory object owned by this context
 * @data:       driver specific context data, managed by the driver
 * @refcount:   reference counter for this structure
 * @releasing:  flag that indicates if context is being released right now.
 *              It is needed to break circular dependency on context during
 *              shared memory release.
 */
struct tee_context {
        struct tee_device *teedev;
        struct list_head list_shm;
        void *data;
        struct kref refcount;
        bool releasing;
};

struct tee_param_memref {
        size_t shm_offs;
        size_t size;
        struct tee_shm *shm;
};

struct tee_param_value {
        u64 a;
        u64 b;
        u64 c;
};

struct tee_param {
        u64 attr;
        union {
                struct tee_param_memref memref;
                struct tee_param_value value;
        } u;
};

/**
 * struct tee_driver_ops - driver operations vtable
 * @get_version:        returns version of driver
 * @open:               called when the device file is opened
 * @release:            release this open file
 * @open_session:       open a new session
 * @close_session:      close a session
 * @invoke_func:        invoke a trusted function
 * @cancel_req:         request cancel of an ongoing invoke or open
 * @supp_revc:          called for supplicant to get a command
 * @supp_send:          called for supplicant to send a response
 * @shm_register:       register shared memory buffer in TEE
 * @shm_unregister:     unregister shared memory buffer in TEE
 */
struct tee_driver_ops {
        void (*get_version)(struct tee_device *teedev,
                            struct tee_ioctl_version_data *vers);
        int (*open)(struct tee_context *ctx);
        void (*release)(struct tee_context *ctx);
        int (*open_session)(struct tee_context *ctx,
                            struct tee_ioctl_open_session_arg *arg,
                            struct tee_param *param);
        int (*close_session)(struct tee_context *ctx, u32 session);
        int (*invoke_func)(struct tee_context *ctx,
                           struct tee_ioctl_invoke_arg *arg,
                           struct tee_param *param);
        int (*cancel_req)(struct tee_context *ctx, u32 cancel_id, u32 session);
        int (*supp_recv)(struct tee_context *ctx, u32 *func, u32 *num_params,
                         struct tee_param *param);
        int (*supp_send)(struct tee_context *ctx, u32 ret, u32 num_params,
                         struct tee_param *param);
        int (*shm_register)(struct tee_context *ctx, struct tee_shm *shm,
                            struct page **pages, size_t num_pages,
                            unsigned long start);
        int (*shm_unregister)(struct tee_context *ctx, struct tee_shm *shm);
};

/**
 * struct tee_desc - Describes the TEE driver to the subsystem
 * @name:       name of driver
 * @ops:        driver operations vtable
 * @owner:      module providing the driver
 * @flags:      Extra properties of driver, defined by TEE_DESC_* below
 */
#define TEE_DESC_PRIVILEGED     0x1
struct tee_desc {
        const char *name;
        const struct tee_driver_ops *ops;
        struct module *owner;
        u32 flags;
};

/**
 * tee_device_alloc() - Allocate a new struct tee_device instance
 * @teedesc:    Descriptor for this driver
 * @dev:        Parent device for this device
 * @pool:       Shared memory pool, NULL if not used
 * @driver_data: Private driver data for this device
 *
 * Allocates a new struct tee_device instance. The device is
 * removed by tee_device_unregister().
 *
 * @returns a pointer to a 'struct tee_device' or an ERR_PTR on failure
 */
struct tee_device *tee_device_alloc(const struct tee_desc *teedesc,
                                    struct device *dev,
                                    struct tee_shm_pool *pool,
                                    void *driver_data);

/**
 * tee_device_register() - Registers a TEE device
 * @teedev:     Device to register
 *
 * tee_device_unregister() need to be called to remove the @teedev if
 * this function fails.
 *
 * @returns < 0 on failure
 */
int tee_device_register(struct tee_device *teedev);

/**
 * tee_device_unregister() - Removes a TEE device
 * @teedev:     Device to unregister
 *
 * This function should be called to remove the @teedev even if
 * tee_device_register() hasn't been called yet. Does nothing if
 * @teedev is NULL.
 */
void tee_device_unregister(struct tee_device *teedev);

/**
 * struct tee_shm - shared memory object
 * @teedev:     device used to allocate the object
 * @ctx:        context using the object, if NULL the context is gone
 * @link        link element
 * @paddr:      physical address of the shared memory
 * @kaddr:      virtual address of the shared memory
 * @size:       size of shared memory
 * @offset:     offset of buffer in user space
 * @pages:      locked pages from userspace
 * @num_pages:  number of locked pages
 * @dmabuf:     dmabuf used to for exporting to user space
 * @flags:      defined by TEE_SHM_* in tee_drv.h
 * @id:         unique id of a shared memory object on this device
 *
 * This pool is only supposed to be accessed directly from the TEE
 * subsystem and from drivers that implements their own shm pool manager.
 */
struct tee_shm {
        struct tee_device *teedev;
        struct tee_context *ctx;
        struct list_head link;
        phys_addr_t paddr;
        void *kaddr;
        size_t size;
        unsigned int offset;
        struct page **pages;
        size_t num_pages;
        struct dma_buf *dmabuf;
        u32 flags;
        int id;
};

/**
 * struct tee_shm_pool_mgr - shared memory manager
 * @ops:                operations
 * @private_data:       private data for the shared memory manager
 */
struct tee_shm_pool_mgr {
        const struct tee_shm_pool_mgr_ops *ops;
        void *private_data;
};

/**
 * struct tee_shm_pool_mgr_ops - shared memory pool manager operations
 * @alloc:              called when allocating shared memory
 * @free:               called when freeing shared memory
 * @destroy_poolmgr:    called when destroying the pool manager
 */
struct tee_shm_pool_mgr_ops {
        int (*alloc)(struct tee_shm_pool_mgr *poolmgr, struct tee_shm *shm,
                     size_t size);
        void (*free)(struct tee_shm_pool_mgr *poolmgr, struct tee_shm *shm);
        void (*destroy_poolmgr)(struct tee_shm_pool_mgr *poolmgr);
};

/**
 * tee_shm_pool_alloc() - Create a shared memory pool from shm managers
 * @priv_mgr:   manager for driver private shared memory allocations
 * @dmabuf_mgr: manager for dma-buf shared memory allocations
 *
 * Allocation with the flag TEE_SHM_DMA_BUF set will use the range supplied
 * in @dmabuf, others will use the range provided by @priv.
 *
 * @returns pointer to a 'struct tee_shm_pool' or an ERR_PTR on failure.
 */
struct tee_shm_pool *tee_shm_pool_alloc(struct tee_shm_pool_mgr *priv_mgr,
                                        struct tee_shm_pool_mgr *dmabuf_mgr);

/*
 * tee_shm_pool_mgr_alloc_res_mem() - Create a shm manager for reserved
 * memory
 * @vaddr:      Virtual address of start of pool
 * @paddr:      Physical address of start of pool
 * @size:       Size in bytes of the pool
 *
 * @returns pointer to a 'struct tee_shm_pool_mgr' or an ERR_PTR on failure.
 */
struct tee_shm_pool_mgr *tee_shm_pool_mgr_alloc_res_mem(unsigned long vaddr,
                                                        phys_addr_t paddr,
                                                        size_t size,
                                                        int min_alloc_order);

/**
 * tee_shm_pool_mgr_destroy() - Free a shared memory manager
 */
static inline void tee_shm_pool_mgr_destroy(struct tee_shm_pool_mgr *poolm)
{
        poolm->ops->destroy_poolmgr(poolm);
}

/**
 * struct tee_shm_pool_mem_info - holds information needed to create a shared
 * memory pool
 * @vaddr:      Virtual address of start of pool
 * @paddr:      Physical address of start of pool
 * @size:       Size in bytes of the pool
 */
struct tee_shm_pool_mem_info {
        unsigned long vaddr;
        phys_addr_t paddr;
        size_t size;
};

/**
 * tee_shm_pool_alloc_res_mem() - Create a shared memory pool from reserved
 * memory range
 * @priv_info:   Information for driver private shared memory pool
 * @dmabuf_info: Information for dma-buf shared memory pool
 *
 * Start and end of pools will must be page aligned.
 *
 * Allocation with the flag TEE_SHM_DMA_BUF set will use the range supplied
 * in @dmabuf, others will use the range provided by @priv.
 *
 * @returns pointer to a 'struct tee_shm_pool' or an ERR_PTR on failure.
 */
struct tee_shm_pool *
tee_shm_pool_alloc_res_mem(struct tee_shm_pool_mem_info *priv_info,
                           struct tee_shm_pool_mem_info *dmabuf_info);

/**
 * tee_shm_pool_free() - Free a shared memory pool
 * @pool:       The shared memory pool to free
 *
 * The must be no remaining shared memory allocated from this pool when
 * this function is called.
 */
void tee_shm_pool_free(struct tee_shm_pool *pool);

/**
 * tee_get_drvdata() - Return driver_data pointer
 * @returns the driver_data pointer supplied to tee_register().
 */
void *tee_get_drvdata(struct tee_device *teedev);

/**
 * tee_shm_alloc() - Allocate shared memory
 * @ctx:        Context that allocates the shared memory
 * @size:       Requested size of shared memory
 * @flags:      Flags setting properties for the requested shared memory.
 *
 * Memory allocated as global shared memory is automatically freed when the
 * TEE file pointer is closed. The @flags field uses the bits defined by
 * TEE_SHM_* above. TEE_SHM_MAPPED must currently always be set. If
 * TEE_SHM_DMA_BUF global shared memory will be allocated and associated
 * with a dma-buf handle, else driver private memory.
 *
 * @returns a pointer to 'struct tee_shm'
 */
struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags);

/**
 * tee_shm_priv_alloc() - Allocate shared memory privately
 * @dev:        Device that allocates the shared memory
 * @size:       Requested size of shared memory
 *
 * Allocates shared memory buffer that is not associated with any client
 * context. Such buffers are owned by TEE driver and used for internal calls.
 *
 * @returns a pointer to 'struct tee_shm'
 */
struct tee_shm *tee_shm_priv_alloc(struct tee_device *teedev, size_t size);

/**
 * tee_shm_register() - Register shared memory buffer
 * @ctx:        Context that registers the shared memory
 * @addr:       Address is userspace of the shared buffer
 * @length:     Length of the shared buffer
 * @flags:      Flags setting properties for the requested shared memory.
 *
 * @returns a pointer to 'struct tee_shm'
 */
struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
                                 size_t length, u32 flags);

/**
 * tee_shm_is_registered() - Check if shared memory object in registered in TEE
 * @shm:        Shared memory handle
 * @returns true if object is registered in TEE
 */
static inline bool tee_shm_is_registered(struct tee_shm *shm)
{
        return shm && (shm->flags & TEE_SHM_REGISTER);
}

/**
 * tee_shm_free() - Free shared memory
 * @shm:        Handle to shared memory to free
 */
void tee_shm_free(struct tee_shm *shm);

/**
 * tee_shm_put() - Decrease reference count on a shared memory handle
 * @shm:        Shared memory handle
 */
void tee_shm_put(struct tee_shm *shm);

/**
 * tee_shm_va2pa() - Get physical address of a virtual address
 * @shm:        Shared memory handle
 * @va:         Virtual address to tranlsate
 * @pa:         Returned physical address
 * @returns 0 on success and < 0 on failure
 */
int tee_shm_va2pa(struct tee_shm *shm, void *va, phys_addr_t *pa);

/**
 * tee_shm_pa2va() - Get virtual address of a physical address
 * @shm:        Shared memory handle
 * @pa:         Physical address to tranlsate
 * @va:         Returned virtual address
 * @returns 0 on success and < 0 on failure
 */
int tee_shm_pa2va(struct tee_shm *shm, phys_addr_t pa, void **va);

/**
 * tee_shm_get_va() - Get virtual address of a shared memory plus an offset
 * @shm:        Shared memory handle
 * @offs:       Offset from start of this shared memory
 * @returns virtual address of the shared memory + offs if offs is within
 *      the bounds of this shared memory, else an ERR_PTR
 */
void *tee_shm_get_va(struct tee_shm *shm, size_t offs);

/**
 * tee_shm_get_pa() - Get physical address of a shared memory plus an offset
 * @shm:        Shared memory handle
 * @offs:       Offset from start of this shared memory
 * @pa:         Physical address to return
 * @returns 0 if offs is within the bounds of this shared memory, else an
 *      error code.
 */
int tee_shm_get_pa(struct tee_shm *shm, size_t offs, phys_addr_t *pa);

/**
 * tee_shm_get_size() - Get size of shared memory buffer
 * @shm:        Shared memory handle
 * @returns size of shared memory
 */
static inline size_t tee_shm_get_size(struct tee_shm *shm)
{
        return shm->size;
}

/**
 * tee_shm_get_pages() - Get list of pages that hold shared buffer
 * @shm:        Shared memory handle
 * @num_pages:  Number of pages will be stored there
 * @returns pointer to pages array
 */
static inline struct page **tee_shm_get_pages(struct tee_shm *shm,
                                              size_t *num_pages)
{
        *num_pages = shm->num_pages;
        return shm->pages;
}

/**
 * tee_shm_get_page_offset() - Get shared buffer offset from page start
 * @shm:        Shared memory handle
 * @returns page offset of shared buffer
 */
static inline size_t tee_shm_get_page_offset(struct tee_shm *shm)
{
        return shm->offset;
}

/**
 * tee_shm_get_id() - Get id of a shared memory object
 * @shm:        Shared memory handle
 * @returns id
 */
static inline int tee_shm_get_id(struct tee_shm *shm)
{
        return shm->id;
}

/**
 * tee_shm_get_from_id() - Find shared memory object and increase reference
 * count
 * @ctx:        Context owning the shared memory
 * @id:         Id of shared memory object
 * @returns a pointer to 'struct tee_shm' on success or an ERR_PTR on failure
 */
struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id);

static inline bool tee_param_is_memref(struct tee_param *param)
{
        switch (param->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
        case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
        case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
        case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
                return true;
        default:
                return false;
        }
}

#endif /*__TEE_DRV_H*/