// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright 2018 NXP
 *   Dong Aisheng <aisheng.dong@nxp.com>
 */

#include <dt-bindings/firmware/imx/rsrc.h>
#include <linux/arm-smccc.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>

#include "clk-scu.h"

#define IMX_SIP_CPUFREQ                 0xC2000001
#define IMX_SIP_SET_CPUFREQ             0x00

static struct imx_sc_ipc *ccm_ipc_handle;
static struct device_node *pd_np;
static struct platform_driver imx_clk_scu_driver;

struct imx_scu_clk_node {
        const char *name;
        u32 rsrc;
        u8 clk_type;
        const char * const *parents;
        int num_parents;

        struct clk_hw *hw;
        struct list_head node;
};

struct list_head imx_scu_clks[IMX_SC_R_LAST];

/*
 * struct clk_scu - Description of one SCU clock
 * @hw: the common clk_hw
 * @rsrc_id: resource ID of this SCU clock
 * @clk_type: type of this clock resource
 */
struct clk_scu {
        struct clk_hw hw;
        u16 rsrc_id;
        u8 clk_type;

        /* for state save&restore */
        bool is_enabled;
        u32 rate;
};

/*
 * struct imx_sc_msg_req_set_clock_rate - clock set rate protocol
 * @hdr: SCU protocol header
 * @rate: rate to set
 * @resource: clock resource to set rate
 * @clk: clk type of this resource
 *
 * This structure describes the SCU protocol of clock rate set
 */
struct imx_sc_msg_req_set_clock_rate {
        struct imx_sc_rpc_msg hdr;
        __le32 rate;
        __le16 resource;
        u8 clk;
} __packed __aligned(4);

struct req_get_clock_rate {
        __le16 resource;
        u8 clk;
} __packed __aligned(4);

struct resp_get_clock_rate {
        __le32 rate;
};

/*
 * struct imx_sc_msg_get_clock_rate - clock get rate protocol
 * @hdr: SCU protocol header
 * @req: get rate request protocol
 * @resp: get rate response protocol
 *
 * This structure describes the SCU protocol of clock rate get
 */
struct imx_sc_msg_get_clock_rate {
        struct imx_sc_rpc_msg hdr;
        union {
                struct req_get_clock_rate req;
                struct resp_get_clock_rate resp;
        } data;
};

/*
 * struct imx_sc_msg_get_clock_parent - clock get parent protocol
 * @hdr: SCU protocol header
 * @req: get parent request protocol
 * @resp: get parent response protocol
 *
 * This structure describes the SCU protocol of clock get parent
 */
struct imx_sc_msg_get_clock_parent {
        struct imx_sc_rpc_msg hdr;
        union {
                struct req_get_clock_parent {
                        __le16 resource;
                        u8 clk;
                } __packed __aligned(4) req;
                struct resp_get_clock_parent {
                        u8 parent;
                } resp;
        } data;
};

/*
 * struct imx_sc_msg_set_clock_parent - clock set parent protocol
 * @hdr: SCU protocol header
 * @req: set parent request protocol
 *
 * This structure describes the SCU protocol of clock set parent
 */
struct imx_sc_msg_set_clock_parent {
        struct imx_sc_rpc_msg hdr;
        __le16 resource;
        u8 clk;
        u8 parent;
} __packed;

/*
 * struct imx_sc_msg_req_clock_enable - clock gate protocol
 * @hdr: SCU protocol header
 * @resource: clock resource to gate
 * @clk: clk type of this resource
 * @enable: whether gate off the clock
 * @autog: HW auto gate enable
 *
 * This structure describes the SCU protocol of clock gate
 */
struct imx_sc_msg_req_clock_enable {
        struct imx_sc_rpc_msg hdr;
        __le16 resource;
        u8 clk;
        u8 enable;
        u8 autog;
} __packed __aligned(4);

static inline struct clk_scu *to_clk_scu(struct clk_hw *hw)
{
        return container_of(hw, struct clk_scu, hw);
}

int imx_clk_scu_init(struct device_node *np)
{
        u32 clk_cells;
        int ret, i;

        ret = imx_scu_get_handle(&ccm_ipc_handle);
        if (ret)
                return ret;

        of_property_read_u32(np, "#clock-cells", &clk_cells);

        if (clk_cells == 2) {
                for (i = 0; i < IMX_SC_R_LAST; i++)
                        INIT_LIST_HEAD(&imx_scu_clks[i]);

                /* pd_np will be used to attach power domains later */
                pd_np = of_find_compatible_node(NULL, NULL, "fsl,scu-pd");
                if (!pd_np)
                        return -EINVAL;
        }

        return platform_driver_register(&imx_clk_scu_driver);
}

/*
 * clk_scu_recalc_rate - Get clock rate for a SCU clock
 * @hw: clock to get rate for
 * @parent_rate: parent rate provided by common clock framework, not used
 *
 * Gets the current clock rate of a SCU clock. Returns the current
 * clock rate, or zero in failure.
 */
static unsigned long clk_scu_recalc_rate(struct clk_hw *hw,
                                         unsigned long parent_rate)
{
        struct clk_scu *clk = to_clk_scu(hw);
        struct imx_sc_msg_get_clock_rate msg;
        struct imx_sc_rpc_msg *hdr = &msg.hdr;
        int ret;

        hdr->ver = IMX_SC_RPC_VERSION;
        hdr->svc = IMX_SC_RPC_SVC_PM;
        hdr->func = IMX_SC_PM_FUNC_GET_CLOCK_RATE;
        hdr->size = 2;

        msg.data.req.resource = cpu_to_le16(clk->rsrc_id);
        msg.data.req.clk = clk->clk_type;

        ret = imx_scu_call_rpc(ccm_ipc_handle, &msg, true);
        if (ret) {
                pr_err("%s: failed to get clock rate %d\n",
                       clk_hw_get_name(hw), ret);
                return 0;
        }

        return le32_to_cpu(msg.data.resp.rate);
}

/*
 * clk_scu_round_rate - Round clock rate for a SCU clock
 * @hw: clock to round rate for
 * @rate: rate to round
 * @parent_rate: parent rate provided by common clock framework, not used
 *
 * Returns the current clock rate, or zero in failure.
 */
static long clk_scu_round_rate(struct clk_hw *hw, unsigned long rate,
                               unsigned long *parent_rate)
{
        /*
         * Assume we support all the requested rate and let the SCU firmware
         * to handle the left work
         */
        return rate;
}

static int clk_scu_atf_set_cpu_rate(struct clk_hw *hw, unsigned long rate,
                                    unsigned long parent_rate)
{
        struct clk_scu *clk = to_clk_scu(hw);
        struct arm_smccc_res res;
        unsigned long cluster_id;

        if (clk->rsrc_id == IMX_SC_R_A35)
                cluster_id = 0;
        else
                return -EINVAL;

        /* CPU frequency scaling can ONLY be done by ARM-Trusted-Firmware */
        arm_smccc_smc(IMX_SIP_CPUFREQ, IMX_SIP_SET_CPUFREQ,
                      cluster_id, rate, 0, 0, 0, 0, &res);

        return 0;
}

/*
 * clk_scu_set_rate - Set rate for a SCU clock
 * @hw: clock to change rate for
 * @rate: target rate for the clock
 * @parent_rate: rate of the clock parent, not used for SCU clocks
 *
 * Sets a clock frequency for a SCU clock. Returns the SCU
 * protocol status.
 */
static int clk_scu_set_rate(struct clk_hw *hw, unsigned long rate,
                            unsigned long parent_rate)
{
        struct clk_scu *clk = to_clk_scu(hw);
        struct imx_sc_msg_req_set_clock_rate msg;
        struct imx_sc_rpc_msg *hdr = &msg.hdr;

        hdr->ver = IMX_SC_RPC_VERSION;
        hdr->svc = IMX_SC_RPC_SVC_PM;
        hdr->func = IMX_SC_PM_FUNC_SET_CLOCK_RATE;
        hdr->size = 3;

        msg.rate = cpu_to_le32(rate);
        msg.resource = cpu_to_le16(clk->rsrc_id);
        msg.clk = clk->clk_type;

        return imx_scu_call_rpc(ccm_ipc_handle, &msg, true);
}

static u8 clk_scu_get_parent(struct clk_hw *hw)
{
        struct clk_scu *clk = to_clk_scu(hw);
        struct imx_sc_msg_get_clock_parent msg;
        struct imx_sc_rpc_msg *hdr = &msg.hdr;
        int ret;

        hdr->ver = IMX_SC_RPC_VERSION;
        hdr->svc = IMX_SC_RPC_SVC_PM;
        hdr->func = IMX_SC_PM_FUNC_GET_CLOCK_PARENT;
        hdr->size = 2;

        msg.data.req.resource = cpu_to_le16(clk->rsrc_id);
        msg.data.req.clk = clk->clk_type;

        ret = imx_scu_call_rpc(ccm_ipc_handle, &msg, true);
        if (ret) {
                pr_err("%s: failed to get clock parent %d\n",
                       clk_hw_get_name(hw), ret);
                return 0;
        }

        return msg.data.resp.parent;
}

static int clk_scu_set_parent(struct clk_hw *hw, u8 index)
{
        struct clk_scu *clk = to_clk_scu(hw);
        struct imx_sc_msg_set_clock_parent msg;
        struct imx_sc_rpc_msg *hdr = &msg.hdr;

        hdr->ver = IMX_SC_RPC_VERSION;
        hdr->svc = IMX_SC_RPC_SVC_PM;
        hdr->func = IMX_SC_PM_FUNC_SET_CLOCK_PARENT;
        hdr->size = 2;

        msg.resource = cpu_to_le16(clk->rsrc_id);
        msg.clk = clk->clk_type;
        msg.parent = index;

        return imx_scu_call_rpc(ccm_ipc_handle, &msg, true);
}

static int sc_pm_clock_enable(struct imx_sc_ipc *ipc, u16 resource,
                              u8 clk, bool enable, bool autog)
{
        struct imx_sc_msg_req_clock_enable msg;
        struct imx_sc_rpc_msg *hdr = &msg.hdr;

        hdr->ver = IMX_SC_RPC_VERSION;
        hdr->svc = IMX_SC_RPC_SVC_PM;
        hdr->func = IMX_SC_PM_FUNC_CLOCK_ENABLE;
        hdr->size = 3;

        msg.resource = cpu_to_le16(resource);
        msg.clk = clk;
        msg.enable = enable;
        msg.autog = autog;

        return imx_scu_call_rpc(ccm_ipc_handle, &msg, true);
}

/*
 * clk_scu_prepare - Enable a SCU clock
 * @hw: clock to enable
 *
 * Enable the clock at the DSC slice level
 */
static int clk_scu_prepare(struct clk_hw *hw)
{
        struct clk_scu *clk = to_clk_scu(hw);

        return sc_pm_clock_enable(ccm_ipc_handle, clk->rsrc_id,
                                  clk->clk_type, true, false);
}

/*
 * clk_scu_unprepare - Disable a SCU clock
 * @hw: clock to enable
 *
 * Disable the clock at the DSC slice level
 */
static void clk_scu_unprepare(struct clk_hw *hw)
{
        struct clk_scu *clk = to_clk_scu(hw);
        int ret;

        ret = sc_pm_clock_enable(ccm_ipc_handle, clk->rsrc_id,
                                 clk->clk_type, false, false);
        if (ret)
                pr_warn("%s: clk unprepare failed %d\n", clk_hw_get_name(hw),
                        ret);
}

static const struct clk_ops clk_scu_ops = {
        .recalc_rate = clk_scu_recalc_rate,
        .round_rate = clk_scu_round_rate,
        .set_rate = clk_scu_set_rate,
        .get_parent = clk_scu_get_parent,
        .set_parent = clk_scu_set_parent,
        .prepare = clk_scu_prepare,
        .unprepare = clk_scu_unprepare,
};

static const struct clk_ops clk_scu_cpu_ops = {
        .recalc_rate = clk_scu_recalc_rate,
        .round_rate = clk_scu_round_rate,
        .set_rate = clk_scu_atf_set_cpu_rate,
        .prepare = clk_scu_prepare,
        .unprepare = clk_scu_unprepare,
};

struct clk_hw *__imx_clk_scu(struct device *dev, const char *name,
                             const char * const *parents, int num_parents,
                             u32 rsrc_id, u8 clk_type)
{
        struct clk_init_data init;
        struct clk_scu *clk;
        struct clk_hw *hw;
        int ret;

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

        clk->rsrc_id = rsrc_id;
        clk->clk_type = clk_type;

        init.name = name;
        init.ops = &clk_scu_ops;
        if (rsrc_id == IMX_SC_R_A35)
                init.ops = &clk_scu_cpu_ops;
        else
                init.ops = &clk_scu_ops;
        init.parent_names = parents;
        init.num_parents = num_parents;

        /*
         * Note on MX8, the clocks are tightly coupled with power domain
         * that once the power domain is off, the clock status may be
         * lost. So we make it NOCACHE to let user to retrieve the real
         * clock status from HW instead of using the possible invalid
         * cached rate.
         */
        init.flags = CLK_GET_RATE_NOCACHE;
        clk->hw.init = &init;

        hw = &clk->hw;
        ret = clk_hw_register(dev, hw);
        if (ret) {
                kfree(clk);
                hw = ERR_PTR(ret);
        }

        if (dev)
                dev_set_drvdata(dev, clk);

        return hw;
}

struct clk_hw *imx_scu_of_clk_src_get(struct of_phandle_args *clkspec,
                                      void *data)
{
        unsigned int rsrc = clkspec->args[0];
        unsigned int idx = clkspec->args[1];
        struct list_head *scu_clks = data;
        struct imx_scu_clk_node *clk;

        list_for_each_entry(clk, &scu_clks[rsrc], node) {
                if (clk->clk_type == idx)
                        return clk->hw;
        }

        return ERR_PTR(-ENODEV);
}

static int imx_clk_scu_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct imx_scu_clk_node *clk = dev_get_platdata(dev);
        struct clk_hw *hw;
        int ret;

        pm_runtime_set_suspended(dev);
        pm_runtime_set_autosuspend_delay(dev, 50);
        pm_runtime_use_autosuspend(&pdev->dev);
        pm_runtime_enable(dev);

        ret = pm_runtime_get_sync(dev);
        if (ret) {
                pm_runtime_disable(dev);
                return ret;
        }

        hw = __imx_clk_scu(dev, clk->name, clk->parents, clk->num_parents,
                           clk->rsrc, clk->clk_type);
        if (IS_ERR(hw)) {
                pm_runtime_disable(dev);
                return PTR_ERR(hw);
        }

        clk->hw = hw;
        list_add_tail(&clk->node, &imx_scu_clks[clk->rsrc]);

        pm_runtime_mark_last_busy(&pdev->dev);
        pm_runtime_put_autosuspend(&pdev->dev);

        dev_dbg(dev, "register SCU clock rsrc:%d type:%d\n", clk->rsrc,
                clk->clk_type);

        return 0;
}

static int __maybe_unused imx_clk_scu_suspend(struct device *dev)
{
        struct clk_scu *clk = dev_get_drvdata(dev);

        clk->rate = clk_hw_get_rate(&clk->hw);
        clk->is_enabled = clk_hw_is_enabled(&clk->hw);

        if (clk->rate)
                dev_dbg(dev, "save rate %d\n", clk->rate);

        if (clk->is_enabled)
                dev_dbg(dev, "save enabled state\n");

        return 0;
}

static int __maybe_unused imx_clk_scu_resume(struct device *dev)
{
        struct clk_scu *clk = dev_get_drvdata(dev);
        int ret = 0;

        if (clk->rate) {
                ret = clk_scu_set_rate(&clk->hw, clk->rate, 0);
                dev_dbg(dev, "restore rate %d %s\n", clk->rate,
                        !ret ? "success" : "failed");
        }

        if (clk->is_enabled) {
                ret = clk_scu_prepare(&clk->hw);
                dev_dbg(dev, "restore enabled state %s\n",
                        !ret ? "success" : "failed");
        }

        return ret;
}

static const struct dev_pm_ops imx_clk_scu_pm_ops = {
        SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_clk_scu_suspend,
                                      imx_clk_scu_resume)
};

static struct platform_driver imx_clk_scu_driver = {
        .driver = {
                .name = "imx-scu-clk",
                .suppress_bind_attrs = true,
                .pm = &imx_clk_scu_pm_ops,
        },
        .probe = imx_clk_scu_probe,
};

static int imx_clk_scu_attach_pd(struct device *dev, u32 rsrc_id)
{
        struct of_phandle_args genpdspec = {
                .np = pd_np,
                .args_count = 1,
                .args[0] = rsrc_id,
        };

        if (rsrc_id == IMX_SC_R_A35 || rsrc_id == IMX_SC_R_A53 ||
            rsrc_id == IMX_SC_R_A72)
                return 0;

        return of_genpd_add_device(&genpdspec, dev);
}

struct clk_hw *imx_clk_scu_alloc_dev(const char *name,
                                     const char * const *parents,
                                     int num_parents, u32 rsrc_id, u8 clk_type)
{
        struct imx_scu_clk_node clk = {
                .name = name,
                .rsrc = rsrc_id,
                .clk_type = clk_type,
                .parents = parents,
                .num_parents = num_parents,
        };
        struct platform_device *pdev;
        int ret;

        pdev = platform_device_alloc(name, PLATFORM_DEVID_NONE);
        if (!pdev) {
                pr_err("%s: failed to allocate scu clk dev rsrc %d type %d\n",
                       name, rsrc_id, clk_type);
                return ERR_PTR(-ENOMEM);
        }

        ret = platform_device_add_data(pdev, &clk, sizeof(clk));
        if (ret) {
                platform_device_put(pdev);
                return ERR_PTR(ret);
        }

        pdev->driver_override = "imx-scu-clk";

        ret = imx_clk_scu_attach_pd(&pdev->dev, rsrc_id);
        if (ret)
                pr_warn("%s: failed to attached the power domain %d\n",
                        name, ret);

        platform_device_add(pdev);

        /* For API backwards compatiblilty, simply return NULL for success */
        return NULL;
}

void imx_clk_scu_unregister(void)
{
        struct imx_scu_clk_node *clk;
        int i;

        for (i = 0; i < IMX_SC_R_LAST; i++) {
                list_for_each_entry(clk, &imx_scu_clks[i], node) {
                        clk_hw_unregister(clk->hw);
                        kfree(clk);
                }
        }
}