/*
 * OPAL IMC interface detection driver
 * Supported on POWERNV platform
 *
 * Copyright    (C) 2017 Madhavan Srinivasan, IBM Corporation.
 *              (C) 2017 Anju T Sudhakar, IBM Corporation.
 *              (C) 2017 Hemant K Shaw, IBM Corporation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or later version.
 */
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/crash_dump.h>
#include <asm/opal.h>
#include <asm/io.h>
#include <asm/imc-pmu.h>
#include <asm/cputhreads.h>
#include <asm/debugfs.h>

static struct dentry *imc_debugfs_parent;

/* Helpers to export imc command and mode via debugfs */
static int imc_mem_get(void *data, u64 *val)
{
        *val = cpu_to_be64(*(u64 *)data);
        return 0;
}

static int imc_mem_set(void *data, u64 val)
{
        *(u64 *)data = cpu_to_be64(val);
        return 0;
}
DEFINE_DEBUGFS_ATTRIBUTE(fops_imc_x64, imc_mem_get, imc_mem_set, "0x%016llx\n");

static struct dentry *imc_debugfs_create_x64(const char *name, umode_t mode,
                                             struct dentry *parent, u64  *value)
{
        return debugfs_create_file_unsafe(name, mode, parent,
                                          value, &fops_imc_x64);
}

/*
 * export_imc_mode_and_cmd: Create a debugfs interface
 *                     for imc_cmd and imc_mode
 *                     for each node in the system.
 *  imc_mode and imc_cmd can be changed by echo into
 *  this interface.
 */
static void export_imc_mode_and_cmd(struct device_node *node,
                                    struct imc_pmu *pmu_ptr)
{
        static u64 loc, *imc_mode_addr, *imc_cmd_addr;
        int chip = 0, nid;
        char mode[16], cmd[16];
        u32 cb_offset;

        imc_debugfs_parent = debugfs_create_dir("imc", powerpc_debugfs_root);

        /*
         * Return here, either because 'imc' directory already exists,
         * Or failed to create a new one.
         */
        if (!imc_debugfs_parent)
                return;

        if (of_property_read_u32(node, "cb_offset", &cb_offset))
                cb_offset = IMC_CNTL_BLK_OFFSET;

        for_each_node(nid) {
                loc = (u64)(pmu_ptr->mem_info[chip].vbase) + cb_offset;
                imc_mode_addr = (u64 *)(loc + IMC_CNTL_BLK_MODE_OFFSET);
                sprintf(mode, "imc_mode_%d", nid);
                if (!imc_debugfs_create_x64(mode, 0600, imc_debugfs_parent,
                                            imc_mode_addr))
                        goto err;

                imc_cmd_addr = (u64 *)(loc + IMC_CNTL_BLK_CMD_OFFSET);
                sprintf(cmd, "imc_cmd_%d", nid);
                if (!imc_debugfs_create_x64(cmd, 0600, imc_debugfs_parent,
                                            imc_cmd_addr))
                        goto err;
                chip++;
        }
        return;

err:
        debugfs_remove_recursive(imc_debugfs_parent);
}

/*
 * imc_get_mem_addr_nest: Function to get nest counter memory region
 * for each chip
 */
static int imc_get_mem_addr_nest(struct device_node *node,
                                 struct imc_pmu *pmu_ptr,
                                 u32 offset)
{
        int nr_chips = 0, i;
        u64 *base_addr_arr, baddr;
        u32 *chipid_arr;

        nr_chips = of_property_count_u32_elems(node, "chip-id");
        if (nr_chips <= 0)
                return -ENODEV;

        base_addr_arr = kcalloc(nr_chips, sizeof(*base_addr_arr), GFP_KERNEL);
        if (!base_addr_arr)
                return -ENOMEM;

        chipid_arr = kcalloc(nr_chips, sizeof(*chipid_arr), GFP_KERNEL);
        if (!chipid_arr) {
                kfree(base_addr_arr);
                return -ENOMEM;
        }

        if (of_property_read_u32_array(node, "chip-id", chipid_arr, nr_chips))
                goto error;

        if (of_property_read_u64_array(node, "base-addr", base_addr_arr,
                                                                nr_chips))
                goto error;

        pmu_ptr->mem_info = kcalloc(nr_chips, sizeof(*pmu_ptr->mem_info),
                                    GFP_KERNEL);
        if (!pmu_ptr->mem_info)
                goto error;

        for (i = 0; i < nr_chips; i++) {
                pmu_ptr->mem_info[i].id = chipid_arr[i];
                baddr = base_addr_arr[i] + offset;
                pmu_ptr->mem_info[i].vbase = phys_to_virt(baddr);
        }

        pmu_ptr->imc_counter_mmaped = true;
        export_imc_mode_and_cmd(node, pmu_ptr);
        kfree(base_addr_arr);
        kfree(chipid_arr);
        return 0;

error:
        kfree(base_addr_arr);
        kfree(chipid_arr);
        return -1;
}

/*
 * imc_pmu_create : Takes the parent device which is the pmu unit, pmu_index
 *                  and domain as the inputs.
 * Allocates memory for the struct imc_pmu, sets up its domain, size and offsets
 */
static int imc_pmu_create(struct device_node *parent, int pmu_index, int domain)
{
        int ret = 0;
        struct imc_pmu *pmu_ptr;
        u32 offset;

        /* memory for pmu */
        pmu_ptr = kzalloc(sizeof(*pmu_ptr), GFP_KERNEL);
        if (!pmu_ptr)
                return -ENOMEM;

        /* Set the domain */
        pmu_ptr->domain = domain;

        ret = of_property_read_u32(parent, "size", &pmu_ptr->counter_mem_size);
        if (ret) {
                ret = -EINVAL;
                goto free_pmu;
        }

        if (!of_property_read_u32(parent, "offset", &offset)) {
                if (imc_get_mem_addr_nest(parent, pmu_ptr, offset)) {
                        ret = -EINVAL;
                        goto free_pmu;
                }
        }

        /* Function to register IMC pmu */
        ret = init_imc_pmu(parent, pmu_ptr, pmu_index);
        if (ret) {
                pr_err("IMC PMU %s Register failed\n", pmu_ptr->pmu.name);
                kfree(pmu_ptr->pmu.name);
                if (pmu_ptr->domain == IMC_DOMAIN_NEST)
                        kfree(pmu_ptr->mem_info);
                kfree(pmu_ptr);
                return ret;
        }

        return 0;

free_pmu:
        kfree(pmu_ptr);
        return ret;
}

static void disable_nest_pmu_counters(void)
{
        int nid, cpu;
        const struct cpumask *l_cpumask;

        get_online_cpus();
        for_each_node_with_cpus(nid) {
                l_cpumask = cpumask_of_node(nid);
                cpu = cpumask_first_and(l_cpumask, cpu_online_mask);
                if (cpu >= nr_cpu_ids)
                        continue;
                opal_imc_counters_stop(OPAL_IMC_COUNTERS_NEST,
                                       get_hard_smp_processor_id(cpu));
        }
        put_online_cpus();
}

static void disable_core_pmu_counters(void)
{
        cpumask_t cores_map;
        int cpu, rc;

        get_online_cpus();
        /* Disable the IMC Core functions */
        cores_map = cpu_online_cores_map();
        for_each_cpu(cpu, &cores_map) {
                rc = opal_imc_counters_stop(OPAL_IMC_COUNTERS_CORE,
                                            get_hard_smp_processor_id(cpu));
                if (rc)
                        pr_err("%s: Failed to stop Core (cpu = %d)\n",
                                __FUNCTION__, cpu);
        }
        put_online_cpus();
}

int get_max_nest_dev(void)
{
        struct device_node *node;
        u32 pmu_units = 0, type;

        for_each_compatible_node(node, NULL, IMC_DTB_UNIT_COMPAT) {
                if (of_property_read_u32(node, "type", &type))
                        continue;

                if (type == IMC_TYPE_CHIP)
                        pmu_units++;
        }

        return pmu_units;
}

static int opal_imc_counters_probe(struct platform_device *pdev)
{
        struct device_node *imc_dev = pdev->dev.of_node;
        int pmu_count = 0, domain;
        bool core_imc_reg = false, thread_imc_reg = false;
        u32 type;

        /*
         * Check whether this is kdump kernel. If yes, force the engines to
         * stop and return.
         */
        if (is_kdump_kernel()) {
                disable_nest_pmu_counters();
                disable_core_pmu_counters();
                return -ENODEV;
        }

        for_each_compatible_node(imc_dev, NULL, IMC_DTB_UNIT_COMPAT) {
                if (of_property_read_u32(imc_dev, "type", &type)) {
                        pr_warn("IMC Device without type property\n");
                        continue;
                }

                switch (type) {
                case IMC_TYPE_CHIP:
                        domain = IMC_DOMAIN_NEST;
                        break;
                case IMC_TYPE_CORE:
                        domain =IMC_DOMAIN_CORE;
                        break;
                case IMC_TYPE_THREAD:
                        domain = IMC_DOMAIN_THREAD;
                        break;
                default:
                        pr_warn("IMC Unknown Device type \n");
                        domain = -1;
                        break;
                }

                if (!imc_pmu_create(imc_dev, pmu_count, domain)) {
                        if (domain == IMC_DOMAIN_NEST)
                                pmu_count++;
                        if (domain == IMC_DOMAIN_CORE)
                                core_imc_reg = true;
                        if (domain == IMC_DOMAIN_THREAD)
                                thread_imc_reg = true;
                }
        }

        /* If none of the nest units are registered, remove debugfs interface */
        if (pmu_count == 0)
                debugfs_remove_recursive(imc_debugfs_parent);

        /* If core imc is not registered, unregister thread-imc */
        if (!core_imc_reg && thread_imc_reg)
                unregister_thread_imc();

        return 0;
}

static void opal_imc_counters_shutdown(struct platform_device *pdev)
{
        /*
         * Function only stops the engines which is bare minimum.
         * TODO: Need to handle proper memory cleanup and pmu
         * unregister.
         */
        disable_nest_pmu_counters();
        disable_core_pmu_counters();
}

static const struct of_device_id opal_imc_match[] = {
        { .compatible = IMC_DTB_COMPAT },
        {},
};

static struct platform_driver opal_imc_driver = {
        .driver = {
                .name = "opal-imc-counters",
                .of_match_table = opal_imc_match,
        },
        .probe = opal_imc_counters_probe,
        .shutdown = opal_imc_counters_shutdown,
};

builtin_platform_driver(opal_imc_driver);