// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2022 Schneider-Electric
 * Author: Miquel Raynal <miquel.raynal@bootlin.com
 * Based on TI crossbar driver written by Peter Ujfalusi <peter.ujfalusi@ti.com>
 */
#include <linux/bitops.h>
#include <linux/of.h>
#include <linux/of_dma.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/soc/renesas/r9a06g032-sysctrl.h>
#include <linux/types.h>

#define RNZ1_DMAMUX_NCELLS 6
#define RZN1_DMAMUX_MAX_LINES 64
#define RZN1_DMAMUX_LINES_PER_CTLR 16

struct rzn1_dmamux_data {
        struct dma_router dmarouter;
        DECLARE_BITMAP(used_chans, 2 * RZN1_DMAMUX_LINES_PER_CTLR);
};

struct rzn1_dmamux_map {
        unsigned int req_idx;
};

static void rzn1_dmamux_free(struct device *dev, void *route_data)
{
        struct rzn1_dmamux_data *dmamux = dev_get_drvdata(dev);
        struct rzn1_dmamux_map *map = route_data;

        dev_dbg(dev, "Unmapping DMAMUX request %u\n", map->req_idx);

        clear_bit(map->req_idx, dmamux->used_chans);

        kfree(map);
}

static void *rzn1_dmamux_route_allocate(struct of_phandle_args *dma_spec,
                                        struct of_dma *ofdma)
{
        struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
        struct rzn1_dmamux_data *dmamux = platform_get_drvdata(pdev);
        struct rzn1_dmamux_map *map;
        unsigned int dmac_idx, chan, val;
        u32 mask;
        int ret;

        if (dma_spec->args_count != RNZ1_DMAMUX_NCELLS) {
                ret = -EINVAL;
                goto put_device;
        }

        map = kzalloc_obj(*map);
        if (!map) {
                ret = -ENOMEM;
                goto put_device;
        }

        chan = dma_spec->args[0];
        map->req_idx = dma_spec->args[4];
        val = dma_spec->args[5];
        dma_spec->args_count -= 2;

        if (chan >= RZN1_DMAMUX_LINES_PER_CTLR) {
                dev_err(&pdev->dev, "Invalid DMA request line: %u\n", chan);
                ret = -EINVAL;
                goto free_map;
        }

        if (map->req_idx >= RZN1_DMAMUX_MAX_LINES ||
            (map->req_idx % RZN1_DMAMUX_LINES_PER_CTLR) != chan) {
                dev_err(&pdev->dev, "Invalid MUX request line: %u\n", map->req_idx);
                ret = -EINVAL;
                goto free_map;
        }

        dmac_idx = map->req_idx >= RZN1_DMAMUX_LINES_PER_CTLR ? 1 : 0;
        dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", dmac_idx);
        if (!dma_spec->np) {
                dev_err(&pdev->dev, "Can't get DMA master\n");
                ret = -EINVAL;
                goto free_map;
        }

        dev_dbg(&pdev->dev, "Mapping DMAMUX request %u to DMAC%u request %u\n",
                map->req_idx, dmac_idx, chan);

        if (test_and_set_bit(map->req_idx, dmamux->used_chans)) {
                ret = -EBUSY;
                goto put_dma_spec_np;
        }

        mask = BIT(map->req_idx);
        ret = r9a06g032_sysctrl_set_dmamux(mask, val ? mask : 0);
        if (ret)
                goto clear_bitmap;

        put_device(&pdev->dev);
        return map;

clear_bitmap:
        clear_bit(map->req_idx, dmamux->used_chans);
put_dma_spec_np:
        of_node_put(dma_spec->np);
free_map:
        kfree(map);
put_device:
        put_device(&pdev->dev);

        return ERR_PTR(ret);
}

#ifdef CONFIG_OF
static const struct of_device_id rzn1_dmac_match[] = {
        { .compatible = "renesas,rzn1-dma" },
        {}
};
#endif

static int rzn1_dmamux_probe(struct platform_device *pdev)
{
        struct device_node *mux_node = pdev->dev.of_node;
        const struct of_device_id *match;
        struct device_node *dmac_node;
        struct rzn1_dmamux_data *dmamux;

        dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
        if (!dmamux)
                return -ENOMEM;

        dmac_node = of_parse_phandle(mux_node, "dma-masters", 0);
        if (!dmac_node)
                return dev_err_probe(&pdev->dev, -ENODEV, "Can't get DMA master node\n");

        match = of_match_node(rzn1_dmac_match, dmac_node);
        of_node_put(dmac_node);
        if (!match)
                return dev_err_probe(&pdev->dev, -EINVAL, "DMA master is not supported\n");

        dmamux->dmarouter.dev = &pdev->dev;
        dmamux->dmarouter.route_free = rzn1_dmamux_free;

        platform_set_drvdata(pdev, dmamux);

        return of_dma_router_register(mux_node, rzn1_dmamux_route_allocate,
                                      &dmamux->dmarouter);
}

static const struct of_device_id rzn1_dmamux_match[] = {
        { .compatible = "renesas,rzn1-dmamux" },
        {}
};
MODULE_DEVICE_TABLE(of, rzn1_dmamux_match);

static struct platform_driver rzn1_dmamux_driver = {
        .driver = {
                .name = "renesas,rzn1-dmamux",
                .of_match_table = rzn1_dmamux_match,
        },
        .probe  = rzn1_dmamux_probe,
};
module_platform_driver(rzn1_dmamux_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com");
MODULE_DESCRIPTION("Renesas RZ/N1 DMAMUX driver");