// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2017-2018, Intel Corporation
 */

#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/genalloc.h>
#include <linux/io.h>
#include <linux/kfifo.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/firmware/intel/stratix10-smc.h>
#include <linux/firmware/intel/stratix10-svc-client.h>
#include <linux/types.h>

/**
 * SVC_NUM_DATA_IN_FIFO - number of struct stratix10_svc_data in the FIFO
 *
 * SVC_NUM_CHANNEL - number of channel supported by service layer driver
 *
 * FPGA_CONFIG_DATA_CLAIM_TIMEOUT_MS - claim back the submitted buffer(s)
 * from the secure world for FPGA manager to reuse, or to free the buffer(s)
 * when all bit-stream data had be send.
 *
 * FPGA_CONFIG_STATUS_TIMEOUT_SEC - poll the FPGA configuration status,
 * service layer will return error to FPGA manager when timeout occurs,
 * timeout is set to 30 seconds (30 * 1000) at Intel Stratix10 SoC.
 */
#define SVC_NUM_DATA_IN_FIFO                    32
#define SVC_NUM_CHANNEL                         2
#define FPGA_CONFIG_DATA_CLAIM_TIMEOUT_MS       200
#define FPGA_CONFIG_STATUS_TIMEOUT_SEC          30

/* stratix10 service layer clients */
#define STRATIX10_RSU                           "stratix10-rsu"

typedef void (svc_invoke_fn)(unsigned long, unsigned long, unsigned long,
                             unsigned long, unsigned long, unsigned long,
                             unsigned long, unsigned long,
                             struct arm_smccc_res *);
struct stratix10_svc_chan;

/**
 * struct stratix10_svc - svc private data
 * @stratix10_svc_rsu: pointer to stratix10 RSU device
 */
struct stratix10_svc {
        struct platform_device *stratix10_svc_rsu;
};

/**
 * struct stratix10_svc_sh_memory - service shared memory structure
 * @sync_complete: state for a completion
 * @addr: physical address of shared memory block
 * @size: size of shared memory block
 * @invoke_fn: function to issue secure monitor or hypervisor call
 *
 * This struct is used to save physical address and size of shared memory
 * block. The shared memory blocked is allocated by secure monitor software
 * at secure world.
 *
 * Service layer driver uses the physical address and size to create a memory
 * pool, then allocates data buffer from that memory pool for service client.
 */
struct stratix10_svc_sh_memory {
        struct completion sync_complete;
        unsigned long addr;
        unsigned long size;
        svc_invoke_fn *invoke_fn;
};

/**
 * struct stratix10_svc_data_mem - service memory structure
 * @vaddr: virtual address
 * @paddr: physical address
 * @size: size of memory
 * @node: link list head node
 *
 * This struct is used in a list that keeps track of buffers which have
 * been allocated or freed from the memory pool. Service layer driver also
 * uses this struct to transfer physical address to virtual address.
 */
struct stratix10_svc_data_mem {
        void *vaddr;
        phys_addr_t paddr;
        size_t size;
        struct list_head node;
};

/**
 * struct stratix10_svc_data - service data structure
 * @chan: service channel
 * @paddr: playload physical address
 * @size: playload size
 * @command: service command requested by client
 * @flag: configuration type (full or partial)
 * @arg: args to be passed via registers and not physically mapped buffers
 *
 * This struct is used in service FIFO for inter-process communication.
 */
struct stratix10_svc_data {
        struct stratix10_svc_chan *chan;
        phys_addr_t paddr;
        size_t size;
        u32 command;
        u32 flag;
        u64 arg[3];
};

/**
 * struct stratix10_svc_controller - service controller
 * @dev: device
 * @chans: array of service channels
 * @num_chans: number of channels in 'chans' array
 * @num_active_client: number of active service client
 * @node: list management
 * @genpool: memory pool pointing to the memory region
 * @task: pointer to the thread task which handles SMC or HVC call
 * @svc_fifo: a queue for storing service message data
 * @complete_status: state for completion
 * @svc_fifo_lock: protect access to service message data queue
 * @invoke_fn: function to issue secure monitor call or hypervisor call
 *
 * This struct is used to create communication channels for service clients, to
 * handle secure monitor or hypervisor call.
 */
struct stratix10_svc_controller {
        struct device *dev;
        struct stratix10_svc_chan *chans;
        int num_chans;
        int num_active_client;
        struct list_head node;
        struct gen_pool *genpool;
        struct task_struct *task;
        struct kfifo svc_fifo;
        struct completion complete_status;
        spinlock_t svc_fifo_lock;
        svc_invoke_fn *invoke_fn;
};

/**
 * struct stratix10_svc_chan - service communication channel
 * @ctrl: pointer to service controller which is the provider of this channel
 * @scl: pointer to service client which owns the channel
 * @name: service client name associated with the channel
 * @lock: protect access to the channel
 *
 * This struct is used by service client to communicate with service layer, each
 * service client has its own channel created by service controller.
 */
struct stratix10_svc_chan {
        struct stratix10_svc_controller *ctrl;
        struct stratix10_svc_client *scl;
        char *name;
        spinlock_t lock;
};

static LIST_HEAD(svc_ctrl);
static LIST_HEAD(svc_data_mem);

/**
 * svc_pa_to_va() - translate physical address to virtual address
 * @addr: to be translated physical address
 *
 * Return: valid virtual address or NULL if the provided physical
 * address doesn't exist.
 */
static void *svc_pa_to_va(unsigned long addr)
{
        struct stratix10_svc_data_mem *pmem;

        pr_debug("claim back P-addr=0x%016x\n", (unsigned int)addr);
        list_for_each_entry(pmem, &svc_data_mem, node)
                if (pmem->paddr == addr)
                        return pmem->vaddr;

        /* physical address is not found */
        return NULL;
}

/**
 * svc_thread_cmd_data_claim() - claim back buffer from the secure world
 * @ctrl: pointer to service layer controller
 * @p_data: pointer to service data structure
 * @cb_data: pointer to callback data structure to service client
 *
 * Claim back the submitted buffers from the secure world and pass buffer
 * back to service client (FPGA manager, etc) for reuse.
 */
static void svc_thread_cmd_data_claim(struct stratix10_svc_controller *ctrl,
                                      struct stratix10_svc_data *p_data,
                                      struct stratix10_svc_cb_data *cb_data)
{
        struct arm_smccc_res res;
        unsigned long timeout;

        reinit_completion(&ctrl->complete_status);
        timeout = msecs_to_jiffies(FPGA_CONFIG_DATA_CLAIM_TIMEOUT_MS);

        pr_debug("%s: claim back the submitted buffer\n", __func__);
        do {
                ctrl->invoke_fn(INTEL_SIP_SMC_FPGA_CONFIG_COMPLETED_WRITE,
                                0, 0, 0, 0, 0, 0, 0, &res);

                if (res.a0 == INTEL_SIP_SMC_STATUS_OK) {
                        if (!res.a1) {
                                complete(&ctrl->complete_status);
                                break;
                        }
                        cb_data->status = BIT(SVC_STATUS_BUFFER_DONE);
                        cb_data->kaddr1 = svc_pa_to_va(res.a1);
                        cb_data->kaddr2 = (res.a2) ?
                                          svc_pa_to_va(res.a2) : NULL;
                        cb_data->kaddr3 = (res.a3) ?
                                          svc_pa_to_va(res.a3) : NULL;
                        p_data->chan->scl->receive_cb(p_data->chan->scl,
                                                      cb_data);
                } else {
                        pr_debug("%s: secure world busy, polling again\n",
                                 __func__);
                }
        } while (res.a0 == INTEL_SIP_SMC_STATUS_OK ||
                 res.a0 == INTEL_SIP_SMC_STATUS_BUSY ||
                 wait_for_completion_timeout(&ctrl->complete_status, timeout));
}

/**
 * svc_thread_cmd_config_status() - check configuration status
 * @ctrl: pointer to service layer controller
 * @p_data: pointer to service data structure
 * @cb_data: pointer to callback data structure to service client
 *
 * Check whether the secure firmware at secure world has finished the FPGA
 * configuration, and then inform FPGA manager the configuration status.
 */
static void svc_thread_cmd_config_status(struct stratix10_svc_controller *ctrl,
                                         struct stratix10_svc_data *p_data,
                                         struct stratix10_svc_cb_data *cb_data)
{
        struct arm_smccc_res res;
        int count_in_sec;

        cb_data->kaddr1 = NULL;
        cb_data->kaddr2 = NULL;
        cb_data->kaddr3 = NULL;
        cb_data->status = BIT(SVC_STATUS_ERROR);

        pr_debug("%s: polling config status\n", __func__);

        count_in_sec = FPGA_CONFIG_STATUS_TIMEOUT_SEC;
        while (count_in_sec) {
                ctrl->invoke_fn(INTEL_SIP_SMC_FPGA_CONFIG_ISDONE,
                                0, 0, 0, 0, 0, 0, 0, &res);
                if ((res.a0 == INTEL_SIP_SMC_STATUS_OK) ||
                    (res.a0 == INTEL_SIP_SMC_STATUS_ERROR))
                        break;

                /*
                 * configuration is still in progress, wait one second then
                 * poll again
                 */
                msleep(1000);
                count_in_sec--;
        }

        if (res.a0 == INTEL_SIP_SMC_STATUS_OK && count_in_sec)
                cb_data->status = BIT(SVC_STATUS_COMPLETED);

        p_data->chan->scl->receive_cb(p_data->chan->scl, cb_data);
}

/**
 * svc_thread_recv_status_ok() - handle the successful status
 * @p_data: pointer to service data structure
 * @cb_data: pointer to callback data structure to service client
 * @res: result from SMC or HVC call
 *
 * Send back the correspond status to the service clients.
 */
static void svc_thread_recv_status_ok(struct stratix10_svc_data *p_data,
                                      struct stratix10_svc_cb_data *cb_data,
                                      struct arm_smccc_res res)
{
        cb_data->kaddr1 = NULL;
        cb_data->kaddr2 = NULL;
        cb_data->kaddr3 = NULL;

        switch (p_data->command) {
        case COMMAND_RECONFIG:
        case COMMAND_RSU_UPDATE:
        case COMMAND_RSU_NOTIFY:
                cb_data->status = BIT(SVC_STATUS_OK);
                break;
        case COMMAND_RECONFIG_DATA_SUBMIT:
                cb_data->status = BIT(SVC_STATUS_BUFFER_SUBMITTED);
                break;
        case COMMAND_RECONFIG_STATUS:
                cb_data->status = BIT(SVC_STATUS_COMPLETED);
                break;
        case COMMAND_RSU_RETRY:
                cb_data->status = BIT(SVC_STATUS_OK);
                cb_data->kaddr1 = &res.a1;
                break;
        default:
                pr_warn("it shouldn't happen\n");
                break;
        }

        pr_debug("%s: call receive_cb\n", __func__);
        p_data->chan->scl->receive_cb(p_data->chan->scl, cb_data);
}

/**
 * svc_normal_to_secure_thread() - the function to run in the kthread
 * @data: data pointer for kthread function
 *
 * Service layer driver creates stratix10_svc_smc_hvc_call kthread on CPU
 * node 0, its function stratix10_svc_secure_call_thread is used to handle
 * SMC or HVC calls between kernel driver and secure monitor software.
 *
 * Return: 0 for success or -ENOMEM on error.
 */
static int svc_normal_to_secure_thread(void *data)
{
        struct stratix10_svc_controller
                        *ctrl = (struct stratix10_svc_controller *)data;
        struct stratix10_svc_data *pdata;
        struct stratix10_svc_cb_data *cbdata;
        struct arm_smccc_res res;
        unsigned long a0, a1, a2;
        int ret_fifo = 0;

        pdata =  kmalloc(sizeof(*pdata), GFP_KERNEL);
        if (!pdata)
                return -ENOMEM;

        cbdata = kmalloc(sizeof(*cbdata), GFP_KERNEL);
        if (!cbdata) {
                kfree(pdata);
                return -ENOMEM;
        }

        /* default set, to remove build warning */
        a0 = INTEL_SIP_SMC_FPGA_CONFIG_LOOPBACK;
        a1 = 0;
        a2 = 0;

        pr_debug("smc_hvc_shm_thread is running\n");

        while (!kthread_should_stop()) {
                ret_fifo = kfifo_out_spinlocked(&ctrl->svc_fifo,
                                                pdata, sizeof(*pdata),
                                                &ctrl->svc_fifo_lock);

                if (!ret_fifo)
                        continue;

                pr_debug("get from FIFO pa=0x%016x, command=%u, size=%u\n",
                         (unsigned int)pdata->paddr, pdata->command,
                         (unsigned int)pdata->size);

                switch (pdata->command) {
                case COMMAND_RECONFIG_DATA_CLAIM:
                        svc_thread_cmd_data_claim(ctrl, pdata, cbdata);
                        continue;
                case COMMAND_RECONFIG:
                        a0 = INTEL_SIP_SMC_FPGA_CONFIG_START;
                        pr_debug("conf_type=%u\n", (unsigned int)pdata->flag);
                        a1 = pdata->flag;
                        a2 = 0;
                        break;
                case COMMAND_RECONFIG_DATA_SUBMIT:
                        a0 = INTEL_SIP_SMC_FPGA_CONFIG_WRITE;
                        a1 = (unsigned long)pdata->paddr;
                        a2 = (unsigned long)pdata->size;
                        break;
                case COMMAND_RECONFIG_STATUS:
                        a0 = INTEL_SIP_SMC_FPGA_CONFIG_ISDONE;
                        a1 = 0;
                        a2 = 0;
                        break;
                case COMMAND_RSU_STATUS:
                        a0 = INTEL_SIP_SMC_RSU_STATUS;
                        a1 = 0;
                        a2 = 0;
                        break;
                case COMMAND_RSU_UPDATE:
                        a0 = INTEL_SIP_SMC_RSU_UPDATE;
                        a1 = pdata->arg[0];
                        a2 = 0;
                        break;
                case COMMAND_RSU_NOTIFY:
                        a0 = INTEL_SIP_SMC_RSU_NOTIFY;
                        a1 = pdata->arg[0];
                        a2 = 0;
                        break;
                case COMMAND_RSU_RETRY:
                        a0 = INTEL_SIP_SMC_RSU_RETRY_COUNTER;
                        a1 = 0;
                        a2 = 0;
                        break;
                default:
                        pr_warn("it shouldn't happen\n");
                        break;
                }
                pr_debug("%s: before SMC call -- a0=0x%016x a1=0x%016x",
                         __func__, (unsigned int)a0, (unsigned int)a1);
                pr_debug(" a2=0x%016x\n", (unsigned int)a2);

                ctrl->invoke_fn(a0, a1, a2, 0, 0, 0, 0, 0, &res);

                pr_debug("%s: after SMC call -- res.a0=0x%016x",
                         __func__, (unsigned int)res.a0);
                pr_debug(" res.a1=0x%016x, res.a2=0x%016x",
                         (unsigned int)res.a1, (unsigned int)res.a2);
                pr_debug(" res.a3=0x%016x\n", (unsigned int)res.a3);

                if (pdata->command == COMMAND_RSU_STATUS) {
                        if (res.a0 == INTEL_SIP_SMC_RSU_ERROR)
                                cbdata->status = BIT(SVC_STATUS_ERROR);
                        else
                                cbdata->status = BIT(SVC_STATUS_OK);

                        cbdata->kaddr1 = &res;
                        cbdata->kaddr2 = NULL;
                        cbdata->kaddr3 = NULL;
                        pdata->chan->scl->receive_cb(pdata->chan->scl, cbdata);
                        continue;
                }

                switch (res.a0) {
                case INTEL_SIP_SMC_STATUS_OK:
                        svc_thread_recv_status_ok(pdata, cbdata, res);
                        break;
                case INTEL_SIP_SMC_STATUS_BUSY:
                        switch (pdata->command) {
                        case COMMAND_RECONFIG_DATA_SUBMIT:
                                svc_thread_cmd_data_claim(ctrl,
                                                          pdata, cbdata);
                                break;
                        case COMMAND_RECONFIG_STATUS:
                                svc_thread_cmd_config_status(ctrl,
                                                             pdata, cbdata);
                                break;
                        default:
                                pr_warn("it shouldn't happen\n");
                                break;
                        }
                        break;
                case INTEL_SIP_SMC_STATUS_REJECTED:
                        pr_debug("%s: STATUS_REJECTED\n", __func__);
                        break;
                case INTEL_SIP_SMC_STATUS_ERROR:
                case INTEL_SIP_SMC_RSU_ERROR:
                        pr_err("%s: STATUS_ERROR\n", __func__);
                        cbdata->status = BIT(SVC_STATUS_ERROR);
                        cbdata->kaddr1 = NULL;
                        cbdata->kaddr2 = NULL;
                        cbdata->kaddr3 = NULL;
                        pdata->chan->scl->receive_cb(pdata->chan->scl, cbdata);
                        break;
                default:
                        pr_warn("Secure firmware doesn't support...\n");

                        /*
                         * be compatible with older version firmware which
                         * doesn't support RSU notify or retry
                         */
                        if ((pdata->command == COMMAND_RSU_RETRY) ||
                                (pdata->command == COMMAND_RSU_NOTIFY)) {
                                cbdata->status =
                                        BIT(SVC_STATUS_NO_SUPPORT);
                                cbdata->kaddr1 = NULL;
                                cbdata->kaddr2 = NULL;
                                cbdata->kaddr3 = NULL;
                                pdata->chan->scl->receive_cb(
                                        pdata->chan->scl, cbdata);
                        }
                        break;

                }
        }

        kfree(cbdata);
        kfree(pdata);

        return 0;
}

/**
 * svc_normal_to_secure_shm_thread() - the function to run in the kthread
 * @data: data pointer for kthread function
 *
 * Service layer driver creates stratix10_svc_smc_hvc_shm kthread on CPU
 * node 0, its function stratix10_svc_secure_shm_thread is used to query the
 * physical address of memory block reserved by secure monitor software at
 * secure world.
 *
 * svc_normal_to_secure_shm_thread() calls do_exit() directly since it is a
 * standlone thread for which no one will call kthread_stop() or return when
 * 'kthread_should_stop()' is true.
 */
static int svc_normal_to_secure_shm_thread(void *data)
{
        struct stratix10_svc_sh_memory
                        *sh_mem = (struct stratix10_svc_sh_memory *)data;
        struct arm_smccc_res res;

        /* SMC or HVC call to get shared memory info from secure world */
        sh_mem->invoke_fn(INTEL_SIP_SMC_FPGA_CONFIG_GET_MEM,
                          0, 0, 0, 0, 0, 0, 0, &res);
        if (res.a0 == INTEL_SIP_SMC_STATUS_OK) {
                sh_mem->addr = res.a1;
                sh_mem->size = res.a2;
        } else {
                pr_err("%s: after SMC call -- res.a0=0x%016x",  __func__,
                       (unsigned int)res.a0);
                sh_mem->addr = 0;
                sh_mem->size = 0;
        }

        complete(&sh_mem->sync_complete);
        do_exit(0);
}

/**
 * svc_get_sh_memory() - get memory block reserved by secure monitor SW
 * @pdev: pointer to service layer device
 * @sh_memory: pointer to service shared memory structure
 *
 * Return: zero for successfully getting the physical address of memory block
 * reserved by secure monitor software, or negative value on error.
 */
static int svc_get_sh_memory(struct platform_device *pdev,
                                    struct stratix10_svc_sh_memory *sh_memory)
{
        struct device *dev = &pdev->dev;
        struct task_struct *sh_memory_task;
        unsigned int cpu = 0;

        init_completion(&sh_memory->sync_complete);

        /* smc or hvc call happens on cpu 0 bound kthread */
        sh_memory_task = kthread_create_on_node(svc_normal_to_secure_shm_thread,
                                               (void *)sh_memory,
                                                cpu_to_node(cpu),
                                                "svc_smc_hvc_shm_thread");
        if (IS_ERR(sh_memory_task)) {
                dev_err(dev, "fail to create stratix10_svc_smc_shm_thread\n");
                return -EINVAL;
        }

        wake_up_process(sh_memory_task);

        if (!wait_for_completion_timeout(&sh_memory->sync_complete, 10 * HZ)) {
                dev_err(dev,
                        "timeout to get sh-memory paras from secure world\n");
                return -ETIMEDOUT;
        }

        if (!sh_memory->addr || !sh_memory->size) {
                dev_err(dev,
                        "failed to get shared memory info from secure world\n");
                return -ENOMEM;
        }

        dev_dbg(dev, "SM software provides paddr: 0x%016x, size: 0x%08x\n",
                (unsigned int)sh_memory->addr,
                (unsigned int)sh_memory->size);

        return 0;
}

/**
 * svc_create_memory_pool() - create a memory pool from reserved memory block
 * @pdev: pointer to service layer device
 * @sh_memory: pointer to service shared memory structure
 *
 * Return: pool allocated from reserved memory block or ERR_PTR() on error.
 */
static struct gen_pool *
svc_create_memory_pool(struct platform_device *pdev,
                       struct stratix10_svc_sh_memory *sh_memory)
{
        struct device *dev = &pdev->dev;
        struct gen_pool *genpool;
        unsigned long vaddr;
        phys_addr_t paddr;
        size_t size;
        phys_addr_t begin;
        phys_addr_t end;
        void *va;
        size_t page_mask = PAGE_SIZE - 1;
        int min_alloc_order = 3;
        int ret;

        begin = roundup(sh_memory->addr, PAGE_SIZE);
        end = rounddown(sh_memory->addr + sh_memory->size, PAGE_SIZE);
        paddr = begin;
        size = end - begin;
        va = memremap(paddr, size, MEMREMAP_WC);
        if (!va) {
                dev_err(dev, "fail to remap shared memory\n");
                return ERR_PTR(-EINVAL);
        }
        vaddr = (unsigned long)va;
        dev_dbg(dev,
                "reserved memory vaddr: %p, paddr: 0x%16x size: 0x%8x\n",
                va, (unsigned int)paddr, (unsigned int)size);
        if ((vaddr & page_mask) || (paddr & page_mask) ||
            (size & page_mask)) {
                dev_err(dev, "page is not aligned\n");
                return ERR_PTR(-EINVAL);
        }
        genpool = gen_pool_create(min_alloc_order, -1);
        if (!genpool) {
                dev_err(dev, "fail to create genpool\n");
                return ERR_PTR(-ENOMEM);
        }
        gen_pool_set_algo(genpool, gen_pool_best_fit, NULL);
        ret = gen_pool_add_virt(genpool, vaddr, paddr, size, -1);
        if (ret) {
                dev_err(dev, "fail to add memory chunk to the pool\n");
                gen_pool_destroy(genpool);
                return ERR_PTR(ret);
        }

        return genpool;
}

/**
 * svc_smccc_smc() - secure monitor call between normal and secure world
 * @a0: argument passed in registers 0
 * @a1: argument passed in registers 1
 * @a2: argument passed in registers 2
 * @a3: argument passed in registers 3
 * @a4: argument passed in registers 4
 * @a5: argument passed in registers 5
 * @a6: argument passed in registers 6
 * @a7: argument passed in registers 7
 * @res: result values from register 0 to 3
 */
static void svc_smccc_smc(unsigned long a0, unsigned long a1,
                          unsigned long a2, unsigned long a3,
                          unsigned long a4, unsigned long a5,
                          unsigned long a6, unsigned long a7,
                          struct arm_smccc_res *res)
{
        arm_smccc_smc(a0, a1, a2, a3, a4, a5, a6, a7, res);
}

/**
 * svc_smccc_hvc() - hypervisor call between normal and secure world
 * @a0: argument passed in registers 0
 * @a1: argument passed in registers 1
 * @a2: argument passed in registers 2
 * @a3: argument passed in registers 3
 * @a4: argument passed in registers 4
 * @a5: argument passed in registers 5
 * @a6: argument passed in registers 6
 * @a7: argument passed in registers 7
 * @res: result values from register 0 to 3
 */
static void svc_smccc_hvc(unsigned long a0, unsigned long a1,
                          unsigned long a2, unsigned long a3,
                          unsigned long a4, unsigned long a5,
                          unsigned long a6, unsigned long a7,
                          struct arm_smccc_res *res)
{
        arm_smccc_hvc(a0, a1, a2, a3, a4, a5, a6, a7, res);
}

/**
 * get_invoke_func() - invoke SMC or HVC call
 * @dev: pointer to device
 *
 * Return: function pointer to svc_smccc_smc or svc_smccc_hvc.
 */
static svc_invoke_fn *get_invoke_func(struct device *dev)
{
        const char *method;

        if (of_property_read_string(dev->of_node, "method", &method)) {
                dev_warn(dev, "missing \"method\" property\n");
                return ERR_PTR(-ENXIO);
        }

        if (!strcmp(method, "smc"))
                return svc_smccc_smc;
        if (!strcmp(method, "hvc"))
                return svc_smccc_hvc;

        dev_warn(dev, "invalid \"method\" property: %s\n", method);

        return ERR_PTR(-EINVAL);
}

/**
 * stratix10_svc_request_channel_byname() - request a service channel
 * @client: pointer to service client
 * @name: service client name
 *
 * This function is used by service client to request a service channel.
 *
 * Return: a pointer to channel assigned to the client on success,
 * or ERR_PTR() on error.
 */
struct stratix10_svc_chan *stratix10_svc_request_channel_byname(
        struct stratix10_svc_client *client, const char *name)
{
        struct device *dev = client->dev;
        struct stratix10_svc_controller *controller;
        struct stratix10_svc_chan *chan = NULL;
        unsigned long flag;
        int i;

        /* if probe was called after client's, or error on probe */
        if (list_empty(&svc_ctrl))
                return ERR_PTR(-EPROBE_DEFER);

        controller = list_first_entry(&svc_ctrl,
                                      struct stratix10_svc_controller, node);
        for (i = 0; i < SVC_NUM_CHANNEL; i++) {
                if (!strcmp(controller->chans[i].name, name)) {
                        chan = &controller->chans[i];
                        break;
                }
        }

        /* if there was no channel match */
        if (i == SVC_NUM_CHANNEL) {
                dev_err(dev, "%s: channel not allocated\n", __func__);
                return ERR_PTR(-EINVAL);
        }

        if (chan->scl || !try_module_get(controller->dev->driver->owner)) {
                dev_dbg(dev, "%s: svc not free\n", __func__);
                return ERR_PTR(-EBUSY);
        }

        spin_lock_irqsave(&chan->lock, flag);
        chan->scl = client;
        chan->ctrl->num_active_client++;
        spin_unlock_irqrestore(&chan->lock, flag);

        return chan;
}
EXPORT_SYMBOL_GPL(stratix10_svc_request_channel_byname);

/**
 * stratix10_svc_free_channel() - free service channel
 * @chan: service channel to be freed
 *
 * This function is used by service client to free a service channel.
 */
void stratix10_svc_free_channel(struct stratix10_svc_chan *chan)
{
        unsigned long flag;

        spin_lock_irqsave(&chan->lock, flag);
        chan->scl = NULL;
        chan->ctrl->num_active_client--;
        module_put(chan->ctrl->dev->driver->owner);
        spin_unlock_irqrestore(&chan->lock, flag);
}
EXPORT_SYMBOL_GPL(stratix10_svc_free_channel);

/**
 * stratix10_svc_send() - send a message data to the remote
 * @chan: service channel assigned to the client
 * @msg: message data to be sent, in the format of
 * "struct stratix10_svc_client_msg"
 *
 * This function is used by service client to add a message to the service
 * layer driver's queue for being sent to the secure world.
 *
 * Return: 0 for success, -ENOMEM or -ENOBUFS on error.
 */
int stratix10_svc_send(struct stratix10_svc_chan *chan, void *msg)
{
        struct stratix10_svc_client_msg
                *p_msg = (struct stratix10_svc_client_msg *)msg;
        struct stratix10_svc_data_mem *p_mem;
        struct stratix10_svc_data *p_data;
        int ret = 0;
        unsigned int cpu = 0;

        p_data = kzalloc(sizeof(*p_data), GFP_KERNEL);
        if (!p_data)
                return -ENOMEM;

        /* first client will create kernel thread */
        if (!chan->ctrl->task) {
                chan->ctrl->task =
                        kthread_create_on_node(svc_normal_to_secure_thread,
                                              (void *)chan->ctrl,
                                              cpu_to_node(cpu),
                                              "svc_smc_hvc_thread");
                        if (IS_ERR(chan->ctrl->task)) {
                                dev_err(chan->ctrl->dev,
                                        "failed to create svc_smc_hvc_thread\n");
                                kfree(p_data);
                                return -EINVAL;
                        }
                kthread_bind(chan->ctrl->task, cpu);
                wake_up_process(chan->ctrl->task);
        }

        pr_debug("%s: sent P-va=%p, P-com=%x, P-size=%u\n", __func__,
                 p_msg->payload, p_msg->command,
                 (unsigned int)p_msg->payload_length);

        if (list_empty(&svc_data_mem)) {
                if (p_msg->command == COMMAND_RECONFIG) {
                        struct stratix10_svc_command_config_type *ct =
                                (struct stratix10_svc_command_config_type *)
                                p_msg->payload;
                        p_data->flag = ct->flags;
                }
        } else {
                list_for_each_entry(p_mem, &svc_data_mem, node)
                        if (p_mem->vaddr == p_msg->payload) {
                                p_data->paddr = p_mem->paddr;
                                break;
                        }
        }

        p_data->command = p_msg->command;
        p_data->arg[0] = p_msg->arg[0];
        p_data->arg[1] = p_msg->arg[1];
        p_data->arg[2] = p_msg->arg[2];
        p_data->size = p_msg->payload_length;
        p_data->chan = chan;
        pr_debug("%s: put to FIFO pa=0x%016x, cmd=%x, size=%u\n", __func__,
               (unsigned int)p_data->paddr, p_data->command,
               (unsigned int)p_data->size);
        ret = kfifo_in_spinlocked(&chan->ctrl->svc_fifo, p_data,
                                  sizeof(*p_data),
                                  &chan->ctrl->svc_fifo_lock);

        kfree(p_data);

        if (!ret)
                return -ENOBUFS;

        return 0;
}
EXPORT_SYMBOL_GPL(stratix10_svc_send);

/**
 * stratix10_svc_done() - complete service request transactions
 * @chan: service channel assigned to the client
 *
 * This function should be called when client has finished its request
 * or there is an error in the request process. It allows the service layer
 * to stop the running thread to have maximize savings in kernel resources.
 */
void stratix10_svc_done(struct stratix10_svc_chan *chan)
{
        /* stop thread when thread is running AND only one active client */
        if (chan->ctrl->task && chan->ctrl->num_active_client <= 1) {
                pr_debug("svc_smc_hvc_shm_thread is stopped\n");
                kthread_stop(chan->ctrl->task);
                chan->ctrl->task = NULL;
        }
}
EXPORT_SYMBOL_GPL(stratix10_svc_done);

/**
 * stratix10_svc_allocate_memory() - allocate memory
 * @chan: service channel assigned to the client
 * @size: memory size requested by a specific service client
 *
 * Service layer allocates the requested number of bytes buffer from the
 * memory pool, service client uses this function to get allocated buffers.
 *
 * Return: address of allocated memory on success, or ERR_PTR() on error.
 */
void *stratix10_svc_allocate_memory(struct stratix10_svc_chan *chan,
                                    size_t size)
{
        struct stratix10_svc_data_mem *pmem;
        unsigned long va;
        phys_addr_t pa;
        struct gen_pool *genpool = chan->ctrl->genpool;
        size_t s = roundup(size, 1 << genpool->min_alloc_order);

        pmem = devm_kzalloc(chan->ctrl->dev, sizeof(*pmem), GFP_KERNEL);
        if (!pmem)
                return ERR_PTR(-ENOMEM);

        va = gen_pool_alloc(genpool, s);
        if (!va)
                return ERR_PTR(-ENOMEM);

        memset((void *)va, 0, s);
        pa = gen_pool_virt_to_phys(genpool, va);

        pmem->vaddr = (void *)va;
        pmem->paddr = pa;
        pmem->size = s;
        list_add_tail(&pmem->node, &svc_data_mem);
        pr_debug("%s: va=%p, pa=0x%016x\n", __func__,
                 pmem->vaddr, (unsigned int)pmem->paddr);

        return (void *)va;
}
EXPORT_SYMBOL_GPL(stratix10_svc_allocate_memory);

/**
 * stratix10_svc_free_memory() - free allocated memory
 * @chan: service channel assigned to the client
 * @kaddr: memory to be freed
 *
 * This function is used by service client to free allocated buffers.
 */
void stratix10_svc_free_memory(struct stratix10_svc_chan *chan, void *kaddr)
{
        struct stratix10_svc_data_mem *pmem;
        size_t size = 0;

        list_for_each_entry(pmem, &svc_data_mem, node)
                if (pmem->vaddr == kaddr) {
                        size = pmem->size;
                        break;
                }

        gen_pool_free(chan->ctrl->genpool, (unsigned long)kaddr, size);
        pmem->vaddr = NULL;
        list_del(&pmem->node);
}
EXPORT_SYMBOL_GPL(stratix10_svc_free_memory);

static const struct of_device_id stratix10_svc_drv_match[] = {
        {.compatible = "intel,stratix10-svc"},
        {},
};

static int stratix10_svc_drv_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct stratix10_svc_controller *controller;
        struct stratix10_svc_chan *chans;
        struct gen_pool *genpool;
        struct stratix10_svc_sh_memory *sh_memory;
        struct stratix10_svc *svc;

        svc_invoke_fn *invoke_fn;
        size_t fifo_size;
        int ret;

        /* get SMC or HVC function */
        invoke_fn = get_invoke_func(dev);
        if (IS_ERR(invoke_fn))
                return -EINVAL;

        sh_memory = devm_kzalloc(dev, sizeof(*sh_memory), GFP_KERNEL);
        if (!sh_memory)
                return -ENOMEM;

        sh_memory->invoke_fn = invoke_fn;
        ret = svc_get_sh_memory(pdev, sh_memory);
        if (ret)
                return ret;

        genpool = svc_create_memory_pool(pdev, sh_memory);
        if (!genpool)
                return -ENOMEM;

        /* allocate service controller and supporting channel */
        controller = devm_kzalloc(dev, sizeof(*controller), GFP_KERNEL);
        if (!controller)
                return -ENOMEM;

        chans = devm_kmalloc_array(dev, SVC_NUM_CHANNEL,
                                   sizeof(*chans), GFP_KERNEL | __GFP_ZERO);
        if (!chans)
                return -ENOMEM;

        controller->dev = dev;
        controller->num_chans = SVC_NUM_CHANNEL;
        controller->num_active_client = 0;
        controller->chans = chans;
        controller->genpool = genpool;
        controller->task = NULL;
        controller->invoke_fn = invoke_fn;
        init_completion(&controller->complete_status);

        fifo_size = sizeof(struct stratix10_svc_data) * SVC_NUM_DATA_IN_FIFO;
        ret = kfifo_alloc(&controller->svc_fifo, fifo_size, GFP_KERNEL);
        if (ret) {
                dev_err(dev, "failed to allocate FIFO\n");
                return ret;

        }
        spin_lock_init(&controller->svc_fifo_lock);

        chans[0].scl = NULL;
        chans[0].ctrl = controller;
        chans[0].name = SVC_CLIENT_FPGA;
        spin_lock_init(&chans[0].lock);

        chans[1].scl = NULL;
        chans[1].ctrl = controller;
        chans[1].name = SVC_CLIENT_RSU;
        spin_lock_init(&chans[1].lock);

        list_add_tail(&controller->node, &svc_ctrl);
        platform_set_drvdata(pdev, controller);

        /* add svc client device(s) */
        svc = devm_kzalloc(dev, sizeof(*svc), GFP_KERNEL);
        if (!svc)
                return -ENOMEM;

        svc->stratix10_svc_rsu = platform_device_alloc(STRATIX10_RSU, 0);
        if (!svc->stratix10_svc_rsu) {
                dev_err(dev, "failed to allocate %s device\n", STRATIX10_RSU);
                return -ENOMEM;
        }

        ret = platform_device_add(svc->stratix10_svc_rsu);
        if (ret) {
                platform_device_put(svc->stratix10_svc_rsu);
                return ret;
        }
        dev_set_drvdata(dev, svc);

        pr_info("Intel Service Layer Driver Initialized\n");

        return ret;
}

static int stratix10_svc_drv_remove(struct platform_device *pdev)
{
        struct stratix10_svc *svc = dev_get_drvdata(&pdev->dev);
        struct stratix10_svc_controller *ctrl = platform_get_drvdata(pdev);

        platform_device_unregister(svc->stratix10_svc_rsu);

        kfifo_free(&ctrl->svc_fifo);
        if (ctrl->task) {
                kthread_stop(ctrl->task);
                ctrl->task = NULL;
        }
        if (ctrl->genpool)
                gen_pool_destroy(ctrl->genpool);
        list_del(&ctrl->node);

        return 0;
}

static struct platform_driver stratix10_svc_driver = {
        .probe = stratix10_svc_drv_probe,
        .remove = stratix10_svc_drv_remove,
        .driver = {
                .name = "stratix10-svc",
                .of_match_table = stratix10_svc_drv_match,
        },
};

static int __init stratix10_svc_init(void)
{
        struct device_node *fw_np;
        struct device_node *np;
        int ret;

        fw_np = of_find_node_by_name(NULL, "firmware");
        if (!fw_np)
                return -ENODEV;

        np = of_find_matching_node(fw_np, stratix10_svc_drv_match);
        if (!np)
                return -ENODEV;

        of_node_put(np);
        ret = of_platform_populate(fw_np, stratix10_svc_drv_match, NULL, NULL);
        if (ret)
                return ret;

        return platform_driver_register(&stratix10_svc_driver);
}

static void __exit stratix10_svc_exit(void)
{
        return platform_driver_unregister(&stratix10_svc_driver);
}

subsys_initcall(stratix10_svc_init);
module_exit(stratix10_svc_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Intel Stratix10 Service Layer Driver");
MODULE_AUTHOR("Richard Gong <richard.gong@intel.com>");
MODULE_ALIAS("platform:stratix10-svc");