// SPDX-License-Identifier: GPL-2.0-only
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/io.h>
#include <linux/mcb.h>

#include "mcb-internal.h"

#define for_each_chameleon_cell(dtype, p)       \
        for ((dtype) = get_next_dtype((p));     \
             (dtype) != CHAMELEON_DTYPE_END;    \
             (dtype) = get_next_dtype((p)))

static inline uint32_t get_next_dtype(void __iomem *p)
{
        uint32_t dtype;

        dtype = readl(p);
        return dtype >> 28;
}

static int chameleon_parse_bdd(struct mcb_bus *bus,
                        struct chameleon_bar *cb,
                        void __iomem *base)
{
        return 0;
}

static int chameleon_parse_gdd(struct mcb_bus *bus,
                        struct chameleon_bar *cb,
                        void __iomem *base, int bar_count)
{
        struct chameleon_gdd __iomem *gdd =
                (struct chameleon_gdd __iomem *) base;
        struct mcb_device *mdev;
        u32 dev_mapbase;
        u32 offset;
        u32 size;
        int ret;
        __le32 reg1;
        __le32 reg2;

        mdev = mcb_alloc_dev(bus);
        if (!mdev)
                return -ENOMEM;

        reg1 = readl(&gdd->reg1);
        reg2 = readl(&gdd->reg2);
        offset = readl(&gdd->offset);
        size = readl(&gdd->size);

        mdev->id = GDD_DEV(reg1);
        mdev->rev = GDD_REV(reg1);
        mdev->var = GDD_VAR(reg1);
        mdev->bar = GDD_BAR(reg2);
        mdev->group = GDD_GRP(reg2);
        mdev->inst = GDD_INS(reg2);

        /*
         * If the BAR is missing, dev_mapbase is zero, or if the
         * device is IO mapped we just print a warning and go on with the
         * next device, instead of completely stop the gdd parser
         */
        if (mdev->bar > bar_count - 1) {
                pr_info("No BAR for 16z%03d\n", mdev->id);
                ret = 0;
                goto err;
        }

        dev_mapbase = cb[mdev->bar].addr;
        if (!dev_mapbase) {
                pr_info("BAR not assigned for 16z%03d\n", mdev->id);
                ret = 0;
                goto err;
        }

        if (dev_mapbase & 0x01) {
                pr_info("IO mapped Device (16z%03d) not yet supported\n",
                        mdev->id);
                ret = 0;
                goto err;
        }

        pr_debug("Found a 16z%03d\n", mdev->id);

        mdev->irq.start = GDD_IRQ(reg1);
        mdev->irq.end = GDD_IRQ(reg1);
        mdev->irq.flags = IORESOURCE_IRQ;

        mdev->mem.start = dev_mapbase + offset;

        mdev->mem.end = mdev->mem.start + size - 1;
        mdev->mem.flags = IORESOURCE_MEM;

        ret = mcb_device_register(bus, mdev);
        if (ret < 0)
                return ret;

        return 0;

err:
        mcb_free_dev(mdev);

        return ret;
}

static void chameleon_parse_bar(void __iomem *base,
                                struct chameleon_bar *cb, int bar_count)
{
        char __iomem *p = base;
        int i;

        /* skip reg1 */
        p += sizeof(__le32);

        for (i = 0; i < bar_count; i++) {
                cb[i].addr = readl(p);
                cb[i].size = readl(p + 4);

                p += sizeof(struct chameleon_bar);
        }
}

static int chameleon_get_bar(void __iomem **base, phys_addr_t mapbase,
                             struct chameleon_bar **cb)
{
        struct chameleon_bar *c;
        int bar_count;
        __le32 reg;
        u32 dtype;

        /*
         * For those devices which are not connected
         * to the PCI Bus (e.g. LPC) there is a bar
         * descriptor located directly after the
         * chameleon header. This header is comparable
         * to a PCI header.
         */
        dtype = get_next_dtype(*base);
        if (dtype == CHAMELEON_DTYPE_BAR) {
                reg = readl(*base);

                bar_count = BAR_CNT(reg);
                if (bar_count <= 0 || bar_count > CHAMELEON_BAR_MAX)
                        return -ENODEV;

                c = kzalloc_objs(struct chameleon_bar, bar_count);
                if (!c)
                        return -ENOMEM;

                chameleon_parse_bar(*base, c, bar_count);
                *base += BAR_DESC_SIZE(bar_count);
        } else {
                c = kzalloc_obj(struct chameleon_bar);
                if (!c)
                        return -ENOMEM;

                bar_count = 1;
                c->addr = mapbase;
        }

        *cb = c;

        return bar_count;
}

int chameleon_parse_cells(struct mcb_bus *bus, phys_addr_t mapbase,
                        void __iomem *base)
{
        struct chameleon_fpga_header *header;
        struct chameleon_bar *cb;
        void __iomem *p = base;
        int num_cells = 0;
        uint32_t dtype;
        int bar_count;
        int ret;
        u32 hsize;
        u32 table_size;

        hsize = sizeof(struct chameleon_fpga_header);

        header = kzalloc(hsize, GFP_KERNEL);
        if (!header)
                return -ENOMEM;

        /* Extract header information */
        memcpy_fromio(header, p, hsize);
        /* We only support chameleon v2 at the moment */
        header->magic = le16_to_cpu(header->magic);
        if (header->magic != CHAMELEONV2_MAGIC) {
                pr_err("Unsupported chameleon version 0x%x\n",
                                header->magic);
                ret = -ENODEV;
                goto free_header;
        }
        p += hsize;

        bus->revision = header->revision;
        bus->model = header->model;
        bus->minor = header->minor;
        snprintf(bus->name, CHAMELEON_FILENAME_LEN + 1, "%s",
                 header->filename);

        bar_count = chameleon_get_bar(&p, mapbase, &cb);
        if (bar_count < 0) {
                ret = bar_count;
                goto free_header;
        }

        for_each_chameleon_cell(dtype, p) {
                switch (dtype) {
                case CHAMELEON_DTYPE_GENERAL:
                        ret = chameleon_parse_gdd(bus, cb, p, bar_count);
                        if (ret < 0)
                                goto free_bar;
                        p += sizeof(struct chameleon_gdd);
                        break;
                case CHAMELEON_DTYPE_BRIDGE:
                        chameleon_parse_bdd(bus, cb, p);
                        p += sizeof(struct chameleon_bdd);
                        break;
                case CHAMELEON_DTYPE_END:
                        break;
                default:
                        pr_err("Invalid chameleon descriptor type 0x%x\n",
                                dtype);
                        ret = -EINVAL;
                        goto free_bar;
                }
                num_cells++;
        }

        if (num_cells == 0) {
                ret = -EINVAL;
                goto free_bar;
        }

        table_size = p - base;
        pr_debug("%d cell(s) found. Chameleon table size: 0x%04x bytes\n", num_cells, table_size);
        kfree(cb);
        kfree(header);
        return table_size;

free_bar:
        kfree(cb);
free_header:
        kfree(header);

        return ret;
}
EXPORT_SYMBOL_NS_GPL(chameleon_parse_cells, "MCB");