// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2015 Google, Inc
 * Written by Simon Glass <sjg@chromium.org>
 * Copyright (c) 2016, NVIDIA CORPORATION.
 * Copyright (c) 2018, Theobroma Systems Design und Consulting GmbH
 */

#define LOG_CATEGORY UCLASS_CLK

#include <common.h>
#include <clk.h>
#include <clk-uclass.h>
#include <dm.h>
#include <dt-structs.h>
#include <errno.h>
#include <log.h>
#include <malloc.h>
#include <asm/global_data.h>
#include <dm/device_compat.h>
#include <dm/device-internal.h>
#include <dm/devres.h>
#include <dm/read.h>
#include <linux/bug.h>
#include <linux/clk-provider.h>
#include <linux/err.h>

static inline const struct clk_ops *clk_dev_ops(struct udevice *dev)
{
        return (const struct clk_ops *)dev->driver->ops;
}

struct clk *dev_get_clk_ptr(struct udevice *dev)
{
        return (struct clk *)dev_get_uclass_priv(dev);
}

#if CONFIG_IS_ENABLED(OF_PLATDATA)
int clk_get_by_phandle(struct udevice *dev, const struct phandle_1_arg *cells,
                       struct clk *clk)
{
        int ret;

        ret = device_get_by_ofplat_idx(cells->idx, &clk->dev);
        if (ret)
                return ret;
        clk->id = cells->arg[0];

        return 0;
}
#endif

#if CONFIG_IS_ENABLED(OF_REAL)
static int clk_of_xlate_default(struct clk *clk,
                                struct ofnode_phandle_args *args)
{
        debug("%s(clk=%p)\n", __func__, clk);

        if (args->args_count > 1) {
                debug("Invaild args_count: %d\n", args->args_count);
                return -EINVAL;
        }

        if (args->args_count)
                clk->id = args->args[0];
        else
                clk->id = 0;

        clk->data = 0;

        return 0;
}

static int clk_get_by_index_tail(int ret, ofnode node,
                                 struct ofnode_phandle_args *args,
                                 const char *list_name, int index,
                                 struct clk *clk)
{
        struct udevice *dev_clk;
        const struct clk_ops *ops;

        assert(clk);
        clk->dev = NULL;
        if (ret)
                goto err;

        ret = uclass_get_device_by_ofnode(UCLASS_CLK, args->node, &dev_clk);
        if (ret) {
                debug("%s: uclass_get_device_by_of_offset failed: err=%d\n",
                      __func__, ret);
                return log_msg_ret("get", ret);
        }

        clk->dev = dev_clk;

        ops = clk_dev_ops(dev_clk);

        if (ops->of_xlate)
                ret = ops->of_xlate(clk, args);
        else
                ret = clk_of_xlate_default(clk, args);
        if (ret) {
                debug("of_xlate() failed: %d\n", ret);
                return log_msg_ret("xlate", ret);
        }

        return clk_request(dev_clk, clk);
err:
        debug("%s: Node '%s', property '%s', failed to request CLK index %d: %d\n",
              __func__, ofnode_get_name(node), list_name, index, ret);

        return log_msg_ret("prop", ret);
}

static int clk_get_by_indexed_prop(struct udevice *dev, const char *prop_name,
                                   int index, struct clk *clk)
{
        int ret;
        struct ofnode_phandle_args args;

        debug("%s(dev=%p, index=%d, clk=%p)\n", __func__, dev, index, clk);

        assert(clk);
        clk->dev = NULL;

        ret = dev_read_phandle_with_args(dev, prop_name, "#clock-cells", 0,
                                         index, &args);
        if (ret) {
                debug("%s: fdtdec_parse_phandle_with_args failed: err=%d\n",
                      __func__, ret);
                return log_ret(ret);
        }


        return clk_get_by_index_tail(ret, dev_ofnode(dev), &args, "clocks",
                                     index, clk);
}

int clk_get_by_index(struct udevice *dev, int index, struct clk *clk)
{
        struct ofnode_phandle_args args;
        int ret;

        ret = dev_read_phandle_with_args(dev, "clocks", "#clock-cells", 0,
                                         index, &args);

        return clk_get_by_index_tail(ret, dev_ofnode(dev), &args, "clocks",
                                     index, clk);
}

int clk_get_by_index_nodev(ofnode node, int index, struct clk *clk)
{
        struct ofnode_phandle_args args;
        int ret;

        ret = ofnode_parse_phandle_with_args(node, "clocks", "#clock-cells", 0,
                                             index, &args);

        return clk_get_by_index_tail(ret, node, &args, "clocks",
                                     index, clk);
}

int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk)
{
        int i, ret, err, count;

        bulk->count = 0;

        count = dev_count_phandle_with_args(dev, "clocks", "#clock-cells", 0);
        if (count < 1)
                return count;

        bulk->clks = devm_kcalloc(dev, count, sizeof(struct clk), GFP_KERNEL);
        if (!bulk->clks)
                return -ENOMEM;

        for (i = 0; i < count; i++) {
                ret = clk_get_by_index(dev, i, &bulk->clks[i]);
                if (ret < 0)
                        goto bulk_get_err;

                ++bulk->count;
        }

        return 0;

bulk_get_err:
        err = clk_release_all(bulk->clks, bulk->count);
        if (err)
                debug("%s: could release all clocks for %p\n",
                      __func__, dev);

        return ret;
}

static struct clk *clk_set_default_get_by_id(struct clk *clk)
{
        struct clk *c = clk;

        if (CONFIG_IS_ENABLED(CLK_CCF)) {
                int ret = clk_get_by_id(clk->id, &c);

                if (ret) {
                        debug("%s(): could not get parent clock pointer, id %lu\n",
                              __func__, clk->id);
                        ERR_PTR(ret);
                }
        }

        return c;
}

static int clk_set_default_parents(struct udevice *dev,
                                   enum clk_defaults_stage stage)
{
        struct clk clk, parent_clk, *c, *p;
        int index;
        int num_parents;
        int ret;

        num_parents = dev_count_phandle_with_args(dev, "assigned-clock-parents",
                                                  "#clock-cells", 0);
        if (num_parents < 0) {
                debug("%s: could not read assigned-clock-parents for %p\n",
                      __func__, dev);
                return 0;
        }

        for (index = 0; index < num_parents; index++) {
                ret = clk_get_by_indexed_prop(dev, "assigned-clock-parents",
                                              index, &parent_clk);
                /* If -ENOENT, this is a no-op entry */
                if (ret == -ENOENT)
                        continue;

                if (ret) {
                        debug("%s: could not get parent clock %d for %s\n",
                              __func__, index, dev_read_name(dev));
                        return ret;
                }

                p = clk_set_default_get_by_id(&parent_clk);
                if (IS_ERR(p))
                        return PTR_ERR(p);

                ret = clk_get_by_indexed_prop(dev, "assigned-clocks",
                                              index, &clk);
                /*
                 * If the clock provider is not ready yet, let it handle
                 * the re-programming later.
                 */
                if (ret == -EPROBE_DEFER) {
                        ret = 0;
                        continue;
                }

                if (ret) {
                        debug("%s: could not get assigned clock %d for %s\n",
                              __func__, index, dev_read_name(dev));
                        return ret;
                }

                /* This is clk provider device trying to reparent itself
                 * It cannot be done right now but need to wait after the
                 * device is probed
                 */
                if (stage == CLK_DEFAULTS_PRE && clk.dev == dev)
                        continue;

                if (stage != CLK_DEFAULTS_PRE && clk.dev != dev)
                        /* do not setup twice the parent clocks */
                        continue;

                c = clk_set_default_get_by_id(&clk);
                if (IS_ERR(c))
                        return PTR_ERR(c);

                ret = clk_set_parent(c, p);
                /*
                 * Not all drivers may support clock-reparenting (as of now).
                 * Ignore errors due to this.
                 */
                if (ret == -ENOSYS)
                        continue;

                if (ret < 0) {
                        debug("%s: failed to reparent clock %d for %s\n",
                              __func__, index, dev_read_name(dev));
                        return ret;
                }
        }

        return 0;
}

static int clk_set_default_rates(struct udevice *dev,
                                 enum clk_defaults_stage stage)
{
        struct clk clk, *c;
        int index;
        int num_rates;
        int size;
        int ret = 0;
        u32 *rates = NULL;

        size = dev_read_size(dev, "assigned-clock-rates");
        if (size < 0)
                return 0;

        num_rates = size / sizeof(u32);
        rates = calloc(num_rates, sizeof(u32));
        if (!rates)
                return -ENOMEM;

        ret = dev_read_u32_array(dev, "assigned-clock-rates", rates, num_rates);
        if (ret)
                goto fail;

        for (index = 0; index < num_rates; index++) {
                /* If 0 is passed, this is a no-op */
                if (!rates[index])
                        continue;

                ret = clk_get_by_indexed_prop(dev, "assigned-clocks",
                                              index, &clk);
                /*
                 * If the clock provider is not ready yet, let it handle
                 * the re-programming later.
                 */
                if (ret == -EPROBE_DEFER) {
                        ret = 0;
                        continue;
                }

                if (ret) {
                        dev_dbg(dev,
                                "could not get assigned clock %d (err = %d)\n",
                                index, ret);
                        continue;
                }

                /* This is clk provider device trying to program itself
                 * It cannot be done right now but need to wait after the
                 * device is probed
                 */
                if (stage == CLK_DEFAULTS_PRE && clk.dev == dev)
                        continue;

                if (stage != CLK_DEFAULTS_PRE && clk.dev != dev)
                        /* do not setup twice the parent clocks */
                        continue;

                c = clk_set_default_get_by_id(&clk);
                if (IS_ERR(c))
                        return PTR_ERR(c);

                ret = clk_set_rate(c, rates[index]);

                if (ret < 0) {
                        dev_warn(dev,
                                 "failed to set rate on clock index %d (%ld) (error = %d)\n",
                                 index, clk.id, ret);
                        break;
                }
        }

fail:
        free(rates);
        return ret;
}

int clk_set_defaults(struct udevice *dev, enum clk_defaults_stage stage)
{
        int ret;

        if (!dev_has_ofnode(dev))
                return 0;

        /*
         * To avoid setting defaults twice, don't set them before relocation.
         * However, still set them for SPL. And still set them if explicitly
         * asked.
         */
        if (!(IS_ENABLED(CONFIG_SPL_BUILD) || (gd->flags & GD_FLG_RELOC)))
                if (stage != CLK_DEFAULTS_POST_FORCE)
                        return 0;

        debug("%s(%s)\n", __func__, dev_read_name(dev));

        ret = clk_set_default_parents(dev, stage);
        if (ret)
                return ret;

        ret = clk_set_default_rates(dev, stage);
        if (ret < 0)
                return ret;

        return 0;
}

int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk)
{
        int index;

        debug("%s(dev=%p, name=%s, clk=%p)\n", __func__, dev, name, clk);
        clk->dev = NULL;

        index = dev_read_stringlist_search(dev, "clock-names", name);
        if (index < 0) {
                debug("fdt_stringlist_search() failed: %d\n", index);
                return index;
        }

        return clk_get_by_index(dev, index, clk);
}
#endif /* OF_REAL */

int clk_get_by_name_nodev(ofnode node, const char *name, struct clk *clk)
{
        int index;

        debug("%s(node=%p, name=%s, clk=%p)\n", __func__,
                ofnode_get_name(node), name, clk);
        clk->dev = NULL;

        index = ofnode_stringlist_search(node, "clock-names", name);
        if (index < 0) {
                debug("fdt_stringlist_search() failed: %d\n", index);
                return index;
        }

        return clk_get_by_index_nodev(node, index, clk);
}

int clk_get_optional_nodev(ofnode node, const char *name, struct clk *clk)
{
        int ret;

        ret = clk_get_by_name_nodev(node, name, clk);
        if (ret == -ENODATA)
                return 0;

        return ret;
}

int clk_release_all(struct clk *clk, int count)
{
        int i, ret;

        for (i = 0; i < count; i++) {
                debug("%s(clk[%d]=%p)\n", __func__, i, &clk[i]);

                /* check if clock has been previously requested */
                if (!clk[i].dev)
                        continue;

                ret = clk_disable(&clk[i]);
                if (ret && ret != -ENOSYS)
                        return ret;

                ret = clk_free(&clk[i]);
                if (ret && ret != -ENOSYS)
                        return ret;
        }

        return 0;
}

int clk_request(struct udevice *dev, struct clk *clk)
{
        const struct clk_ops *ops;

        debug("%s(dev=%p, clk=%p)\n", __func__, dev, clk);
        if (!clk)
                return 0;
        ops = clk_dev_ops(dev);

        clk->dev = dev;

        if (!ops->request)
                return 0;

        return ops->request(clk);
}

int clk_free(struct clk *clk)
{
        const struct clk_ops *ops;

        debug("%s(clk=%p)\n", __func__, clk);
        if (!clk_valid(clk))
                return 0;
        ops = clk_dev_ops(clk->dev);

        if (!ops->rfree)
                return 0;

        return ops->rfree(clk);
}

ulong clk_get_rate(struct clk *clk)
{
        const struct clk_ops *ops;
        int ret;

        debug("%s(clk=%p)\n", __func__, clk);
        if (!clk_valid(clk))
                return 0;
        ops = clk_dev_ops(clk->dev);

        if (!ops->get_rate)
                return -ENOSYS;

        ret = ops->get_rate(clk);
        if (ret)
                return log_ret(ret);

        return 0;
}

struct clk *clk_get_parent(struct clk *clk)
{
        struct udevice *pdev;
        struct clk *pclk;

        debug("%s(clk=%p)\n", __func__, clk);
        if (!clk_valid(clk))
                return NULL;

        pdev = dev_get_parent(clk->dev);
        if (!pdev)
                return ERR_PTR(-ENODEV);
        pclk = dev_get_clk_ptr(pdev);
        if (!pclk)
                return ERR_PTR(-ENODEV);

        return pclk;
}

long long clk_get_parent_rate(struct clk *clk)
{
        const struct clk_ops *ops;
        struct clk *pclk;

        debug("%s(clk=%p)\n", __func__, clk);
        if (!clk_valid(clk))
                return 0;

        pclk = clk_get_parent(clk);
        if (IS_ERR(pclk))
                return -ENODEV;

        ops = clk_dev_ops(pclk->dev);
        if (!ops->get_rate)
                return -ENOSYS;

        /* Read the 'rate' if not already set or if proper flag set*/
        if (!pclk->rate || pclk->flags & CLK_GET_RATE_NOCACHE)
                pclk->rate = clk_get_rate(pclk);

        return pclk->rate;
}

ulong clk_round_rate(struct clk *clk, ulong rate)
{
        const struct clk_ops *ops;

        debug("%s(clk=%p, rate=%lu)\n", __func__, clk, rate);
        if (!clk_valid(clk))
                return 0;

        ops = clk_dev_ops(clk->dev);
        if (!ops->round_rate)
                return -ENOSYS;

        return ops->round_rate(clk, rate);
}

static void clk_clean_rate_cache(struct clk *clk)
{
        struct udevice *child_dev;
        struct clk *clkp;

        if (!clk)
                return;

        clk->rate = 0;

        list_for_each_entry(child_dev, &clk->dev->child_head, sibling_node) {
                clkp = dev_get_clk_ptr(child_dev);
                clk_clean_rate_cache(clkp);
        }
}

ulong clk_set_rate(struct clk *clk, ulong rate)
{
        const struct clk_ops *ops;

        debug("%s(clk=%p, rate=%lu)\n", __func__, clk, rate);
        if (!clk_valid(clk))
                return 0;
        ops = clk_dev_ops(clk->dev);

        if (!ops->set_rate)
                return -ENOSYS;

        /* Clean up cached rates for us and all child clocks */
        clk_clean_rate_cache(clk);

        return ops->set_rate(clk, rate);
}

int clk_set_parent(struct clk *clk, struct clk *parent)
{
        const struct clk_ops *ops;
        int ret;

        debug("%s(clk=%p, parent=%p)\n", __func__, clk, parent);
        if (!clk_valid(clk))
                return 0;
        ops = clk_dev_ops(clk->dev);

        if (!ops->set_parent)
                return -ENOSYS;

        ret = ops->set_parent(clk, parent);
        if (ret)
                return ret;

        if (CONFIG_IS_ENABLED(CLK_CCF))
                ret = device_reparent(clk->dev, parent->dev);

        return ret;
}

int clk_enable(struct clk *clk)
{
        const struct clk_ops *ops;
        struct clk *clkp = NULL;
        int ret;

        debug("%s(clk=%p)\n", __func__, clk);
        if (!clk_valid(clk))
                return 0;
        ops = clk_dev_ops(clk->dev);

        if (CONFIG_IS_ENABLED(CLK_CCF)) {
                /* Take id 0 as a non-valid clk, such as dummy */
                if (clk->id && !clk_get_by_id(clk->id, &clkp)) {
                        if (clkp->enable_count) {
                                clkp->enable_count++;
                                return 0;
                        }
                        if (clkp->dev->parent &&
                            device_get_uclass_id(clkp->dev) == UCLASS_CLK) {
                                ret = clk_enable(dev_get_clk_ptr(clkp->dev->parent));
                                if (ret) {
                                        printf("Enable %s failed\n",
                                               clkp->dev->parent->name);
                                        return ret;
                                }
                        }
                }

                if (ops->enable) {
                        ret = ops->enable(clk);
                        if (ret) {
                                printf("Enable %s failed\n", clk->dev->name);
                                return ret;
                        }
                }
                if (clkp)
                        clkp->enable_count++;
        } else {
                if (!ops->enable)
                        return -ENOSYS;
                return ops->enable(clk);
        }

        return 0;
}

int clk_enable_bulk(struct clk_bulk *bulk)
{
        int i, ret;

        for (i = 0; i < bulk->count; i++) {
                ret = clk_enable(&bulk->clks[i]);
                if (ret < 0 && ret != -ENOSYS)
                        return ret;
        }

        return 0;
}

int clk_disable(struct clk *clk)
{
        const struct clk_ops *ops;
        struct clk *clkp = NULL;
        int ret;

        debug("%s(clk=%p)\n", __func__, clk);
        if (!clk_valid(clk))
                return 0;
        ops = clk_dev_ops(clk->dev);

        if (CONFIG_IS_ENABLED(CLK_CCF)) {
                if (clk->id && !clk_get_by_id(clk->id, &clkp)) {
                        if (clkp->flags & CLK_IS_CRITICAL)
                                return 0;

                        if (clkp->enable_count == 0) {
                                printf("clk %s already disabled\n",
                                       clkp->dev->name);
                                return 0;
                        }

                        if (--clkp->enable_count > 0)
                                return 0;
                }

                if (ops->disable) {
                        ret = ops->disable(clk);
                        if (ret)
                                return ret;
                }

                if (clkp && clkp->dev->parent &&
                    device_get_uclass_id(clkp->dev) == UCLASS_CLK) {
                        ret = clk_disable(dev_get_clk_ptr(clkp->dev->parent));
                        if (ret) {
                                printf("Disable %s failed\n",
                                       clkp->dev->parent->name);
                                return ret;
                        }
                }
        } else {
                if (!ops->disable)
                        return -ENOSYS;

                return ops->disable(clk);
        }

        return 0;
}

int clk_disable_bulk(struct clk_bulk *bulk)
{
        int i, ret;

        for (i = 0; i < bulk->count; i++) {
                ret = clk_disable(&bulk->clks[i]);
                if (ret < 0 && ret != -ENOSYS)
                        return ret;
        }

        return 0;
}

int clk_get_by_id(ulong id, struct clk **clkp)
{
        struct udevice *dev;
        struct uclass *uc;
        int ret;

        ret = uclass_get(UCLASS_CLK, &uc);
        if (ret)
                return ret;

        uclass_foreach_dev(dev, uc) {
                struct clk *clk = dev_get_clk_ptr(dev);

                if (clk && clk->id == id) {
                        *clkp = clk;
                        return 0;
                }
        }

        return -ENOENT;
}

bool clk_is_match(const struct clk *p, const struct clk *q)
{
        /* trivial case: identical struct clk's or both NULL */
        if (p == q)
                return true;

        /* trivial case #2: on the clk pointer is NULL */
        if (!p || !q)
                return false;

        /* same device, id and data */
        if (p->dev == q->dev && p->id == q->id && p->data == q->data)
                return true;

        return false;
}

static void devm_clk_release(struct udevice *dev, void *res)
{
        clk_free(res);
}

static int devm_clk_match(struct udevice *dev, void *res, void *data)
{
        return res == data;
}

struct clk *devm_clk_get(struct udevice *dev, const char *id)
{
        int rc;
        struct clk *clk;

        clk = devres_alloc(devm_clk_release, sizeof(struct clk), __GFP_ZERO);
        if (unlikely(!clk))
                return ERR_PTR(-ENOMEM);

        rc = clk_get_by_name(dev, id, clk);
        if (rc)
                return ERR_PTR(rc);

        devres_add(dev, clk);
        return clk;
}

struct clk *devm_clk_get_optional(struct udevice *dev, const char *id)
{
        struct clk *clk = devm_clk_get(dev, id);

        if (PTR_ERR(clk) == -ENODATA)
                return NULL;

        return clk;
}

void devm_clk_put(struct udevice *dev, struct clk *clk)
{
        int rc;

        if (!clk)
                return;

        rc = devres_release(dev, devm_clk_release, devm_clk_match, clk);
        WARN_ON(rc);
}

int clk_uclass_post_probe(struct udevice *dev)
{
        /*
         * when a clock provider is probed. Call clk_set_defaults()
         * also after the device is probed. This takes care of cases
         * where the DT is used to setup default parents and rates
         * using assigned-clocks
         */
        clk_set_defaults(dev, CLK_DEFAULTS_POST);

        return 0;
}

UCLASS_DRIVER(clk) = {
        .id             = UCLASS_CLK,
        .name           = "clk",
        .post_probe     = clk_uclass_post_probe,
};