// SPDX-License-Identifier: BSD-3-Clause
/*
 * Copyright (c) 2020, MIPI Alliance, Inc.
 *
 * Author: Nicolas Pitre <npitre@baylibre.com>
 */

#include <linux/bitfield.h>
#include <linux/bitmap.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/i3c/master.h>
#include <linux/io.h>

#include "hci.h"
#include "dat.h"

/*
 * Device Address Table Structure
 */

#define DAT_1_AUTOCMD_HDR_CODE          W1_MASK(58, 51)
#define DAT_1_AUTOCMD_MODE              W1_MASK(50, 48)
#define DAT_1_AUTOCMD_VALUE             W1_MASK(47, 40)
#define DAT_1_AUTOCMD_MASK              W1_MASK(39, 32)
/*      DAT_0_I2C_DEVICE                W0_BIT_(31) */
#define DAT_0_DEV_NACK_RETRY_CNT        W0_MASK(30, 29)
#define DAT_0_RING_ID                   W0_MASK(28, 26)
#define DAT_0_DYNADDR_PARITY            W0_BIT_(23)
#define DAT_0_DYNAMIC_ADDRESS           W0_MASK(22, 16)
#define DAT_0_TS                        W0_BIT_(15)
#define DAT_0_MR_REJECT                 W0_BIT_(14)
/*      DAT_0_SIR_REJECT                W0_BIT_(13) */
/*      DAT_0_IBI_PAYLOAD               W0_BIT_(12) */
#define DAT_0_STATIC_ADDRESS            W0_MASK(6, 0)

#define dat_w0_read(i)          hci->DAT[i].w0
#define dat_w1_read(i)          hci->DAT[i].w1
#define dat_w0_write(i, v)      hci_dat_w0_write(hci, i, v)
#define dat_w1_write(i, v)      hci_dat_w1_write(hci, i, v)

static inline void hci_dat_w0_write(struct i3c_hci *hci, int i, u32 v)
{
        hci->DAT[i].w0 = v;
        writel(v, hci->DAT_regs + i * 8);
}

static inline void hci_dat_w1_write(struct i3c_hci *hci, int i, u32 v)
{
        hci->DAT[i].w1 = v;
        writel(v, hci->DAT_regs + i * 8 + 4);
}

static int hci_dat_v1_init(struct i3c_hci *hci)
{
        struct device *dev = hci->master.dev.parent;
        unsigned int dat_idx;

        if (!hci->DAT_regs) {
                dev_err(&hci->master.dev,
                        "only DAT in register space is supported at the moment\n");
                return -EOPNOTSUPP;
        }
        if (hci->DAT_entry_size != 8) {
                dev_err(&hci->master.dev,
                        "only 8-bytes DAT entries are supported at the moment\n");
                return -EOPNOTSUPP;
        }

        if (!hci->DAT) {
                hci->DAT = devm_kcalloc(dev, hci->DAT_entries, hci->DAT_entry_size, GFP_KERNEL);
                if (!hci->DAT)
                        return -ENOMEM;
        }

        if (!hci->DAT_data) {
                /* use a bitmap for faster free slot search */
                hci->DAT_data = devm_bitmap_zalloc(dev, hci->DAT_entries, GFP_KERNEL);
                if (!hci->DAT_data)
                        return -ENOMEM;

                /* clear them */
                for (dat_idx = 0; dat_idx < hci->DAT_entries; dat_idx++) {
                        dat_w0_write(dat_idx, 0);
                        dat_w1_write(dat_idx, 0);
                }
        }

        return 0;
}

static int hci_dat_v1_alloc_entry(struct i3c_hci *hci)
{
        unsigned int dat_idx;
        int ret;

        if (!hci->DAT_data) {
                ret = hci_dat_v1_init(hci);
                if (ret)
                        return ret;
        }
        dat_idx = find_first_zero_bit(hci->DAT_data, hci->DAT_entries);
        if (dat_idx >= hci->DAT_entries)
                return -ENOENT;
        __set_bit(dat_idx, hci->DAT_data);

        /* default flags */
        dat_w0_write(dat_idx, DAT_0_SIR_REJECT | DAT_0_MR_REJECT);

        return dat_idx;
}

static void hci_dat_v1_free_entry(struct i3c_hci *hci, unsigned int dat_idx)
{
        dat_w0_write(dat_idx, 0);
        dat_w1_write(dat_idx, 0);
        if (hci->DAT_data)
                __clear_bit(dat_idx, hci->DAT_data);
}

static void hci_dat_v1_set_dynamic_addr(struct i3c_hci *hci,
                                        unsigned int dat_idx, u8 address)
{
        u32 dat_w0;

        dat_w0 = dat_w0_read(dat_idx);
        dat_w0 &= ~(DAT_0_DYNAMIC_ADDRESS | DAT_0_DYNADDR_PARITY);
        dat_w0 |= FIELD_PREP(DAT_0_DYNAMIC_ADDRESS, address) |
                  (parity8(address) ? 0 : DAT_0_DYNADDR_PARITY);
        dat_w0_write(dat_idx, dat_w0);
}

static void hci_dat_v1_set_static_addr(struct i3c_hci *hci,
                                       unsigned int dat_idx, u8 address)
{
        u32 dat_w0;

        dat_w0 = dat_w0_read(dat_idx);
        dat_w0 &= ~DAT_0_STATIC_ADDRESS;
        dat_w0 |= FIELD_PREP(DAT_0_STATIC_ADDRESS, address);
        dat_w0_write(dat_idx, dat_w0);
}

static void hci_dat_v1_set_flags(struct i3c_hci *hci, unsigned int dat_idx,
                                 u32 w0_flags, u32 w1_flags)
{
        u32 dat_w0, dat_w1;

        dat_w0 = dat_w0_read(dat_idx);
        dat_w1 = dat_w1_read(dat_idx);
        dat_w0 |= w0_flags;
        dat_w1 |= w1_flags;
        dat_w0_write(dat_idx, dat_w0);
        dat_w1_write(dat_idx, dat_w1);
}

static void hci_dat_v1_clear_flags(struct i3c_hci *hci, unsigned int dat_idx,
                                   u32 w0_flags, u32 w1_flags)
{
        u32 dat_w0, dat_w1;

        dat_w0 = dat_w0_read(dat_idx);
        dat_w1 = dat_w1_read(dat_idx);
        dat_w0 &= ~w0_flags;
        dat_w1 &= ~w1_flags;
        dat_w0_write(dat_idx, dat_w0);
        dat_w1_write(dat_idx, dat_w1);
}

static int hci_dat_v1_get_index(struct i3c_hci *hci, u8 dev_addr)
{
        unsigned int dat_idx;
        u32 dat_w0;

        for_each_set_bit(dat_idx, hci->DAT_data, hci->DAT_entries) {
                dat_w0 = dat_w0_read(dat_idx);
                if (FIELD_GET(DAT_0_DYNAMIC_ADDRESS, dat_w0) == dev_addr)
                        return dat_idx;
        }

        return -ENODEV;
}

static void hci_dat_v1_restore(struct i3c_hci *hci)
{
        for (int i = 0; i < hci->DAT_entries; i++) {
                writel(hci->DAT[i].w0, hci->DAT_regs + i * 8);
                writel(hci->DAT[i].w1, hci->DAT_regs + i * 8 + 4);
        }
}

const struct hci_dat_ops mipi_i3c_hci_dat_v1 = {
        .init                   = hci_dat_v1_init,
        .alloc_entry            = hci_dat_v1_alloc_entry,
        .free_entry             = hci_dat_v1_free_entry,
        .set_dynamic_addr       = hci_dat_v1_set_dynamic_addr,
        .set_static_addr        = hci_dat_v1_set_static_addr,
        .set_flags              = hci_dat_v1_set_flags,
        .clear_flags            = hci_dat_v1_clear_flags,
        .get_index              = hci_dat_v1_get_index,
        .restore                = hci_dat_v1_restore,
};