/* SPDX-License-Identifier: MIT */

#include "adt.h"
#include "pcie.h"
#include "pmgr.h"
#include "tunables.h"
#include "utils.h"

/*
 * The ADT uses 17 register sets:
 *
 * 0:  90000000 00000006 10000000 00000000  ECAM
 * 1:  80000000 00000006 00040000 00000000  RC
 * 2:  80080000 00000006 00090000 00000000  PHY
 * 3:  800c0000 00000006 00020000 00000000  PHY IP
 * 4:  8c000000 00000006 00004000 00000000  AXI
 * 5:  3d2bc000 00000000 00001000 00000000  fuses
 * 6:  81000000 00000006 00008000 00000000  port 0 config
 * 7:  81010000 00000006 00001000 00000000  port 0 LTSSM debug
 * 8:  80084000 00000006 00004000 00000000  port 0 PHY
 * 9:  800c8000 00000006 00016610 00000000  port 0 PHY IP
   <macOS 12.0 RC and later add a per-port Intr2AXI reg here>
 * 10: 82000000 00000006 00008000 00000000  port 1 config
 * 11: 82010000 00000006 00001000 00000000  port 1 LTSSM debug
 * 12: 80088000 00000006 00004000 00000000  port 1 PHY
 * 13: 800d0000 00000006 00006000 00000000  port 1 PHY IP
   <...>
 * 14: 83000000 00000006 00008000 00000000  port 2 config
 * 15: 83010000 00000006 00001000 00000000  port 2 LTSSM debug
 * 16: 8008c000 00000006 00004000 00000000  port 2 PHY
 * 17: 800d8000 00000006 00006000 00000000  port 2 PHY IP
   <...>
 */

/* PHY registers */

#define APCIE_PHY_CTRL         0x000
#define APCIE_PHY_CTRL_CLK0REQ BIT(0)
#define APCIE_PHY_CTRL_CLK1REQ BIT(1)
#define APCIE_PHY_CTRL_CLK0ACK BIT(2)
#define APCIE_PHY_CTRL_CLK1ACK BIT(3)
#define APCIE_PHY_CTRL_RESET   BIT(7)

#define APCIE_PHYIF_CTRL     0x024
#define APCIE_PHYIF_CTRL_RUN BIT(0)

/* Port registers */

#define APCIE_PORT_LINKSTS      0x208
#define APCIE_PORT_LINKSTS_BUSY BIT(2)

#define APCIE_PORT_APPCLK    0x800
#define APCIE_PORT_APPCLK_EN BIT(0)

#define APCIE_PORT_STATUS     0x804
#define APCIE_PORT_STATUS_RUN BIT(0)

#define APCIE_PORT_RESET     0x814
#define APCIE_PORT_RESET_DIS BIT(0)

/* PCIe capability registers */
#define PCIE_CAP_BASE    0x70
#define PCIE_LNKCAP      0x0c
#define PCIE_LNKCAP_SLS  GENMASK(3, 0)
#define PCIE_LNKCAP2     0x2c
#define PCIE_LNKCAP2_SLS GENMASK(6, 1)
#define PCIE_LNKCTL2     0x30
#define PCIE_LNKCTL2_TLS GENMASK(3, 0)

/* DesignWare PCIe Core registers */

#define DWC_DBI_RO_WR    0x8bc
#define DWC_DBI_RO_WR_EN BIT(0)

#define DWC_DBI_LINK_WIDTH_SPEED_CONTROL 0x80c
#define DWC_DBI_SPEED_CHANGE             BIT(17)

struct fuse_bits {
    u16 src_reg;
    u16 tgt_reg;
    u8 src_bit;
    u8 tgt_bit;
    u8 width;
};

const struct fuse_bits pcie_fuse_bits_t8103[] = {
    {0x0084, 0x6238, 4, 0, 6},   {0x0084, 0x6220, 10, 14, 3}, {0x0084, 0x62a4, 13, 17, 2},
    {0x0418, 0x522c, 27, 9, 2},  {0x0418, 0x522c, 13, 12, 3}, {0x0418, 0x5220, 18, 14, 3},
    {0x0418, 0x52a4, 21, 17, 2}, {0x0418, 0x522c, 23, 16, 5}, {0x0418, 0x5278, 23, 20, 3},
    {0x0418, 0x5018, 31, 2, 1},  {0x041c, 0x1204, 0, 2, 5},   {},
};

const struct fuse_bits pcie_fuse_bits_t6000[] = {
    {0x004c, 0x1004, 3, 2, 5},   {0x0048, 0x522c, 26, 16, 5}, {0x0048, 0x522c, 29, 9, 2},
    {0x0048, 0x522c, 26, 12, 3}, {0x0048, 0x522c, 26, 16, 5}, {0x0048, 0x52a4, 24, 17, 2},
    {0x004c, 0x5018, 2, 3, 1},   {0x0048, 0x50a4, 14, 17, 2}, {0x0048, 0x62a4, 14, 17, 2},
    {0x0048, 0x6220, 8, 14, 3},  {0x0048, 0x6238, 2, 0, 6},   {},
};

/* clang-format off */
const struct fuse_bits pcie_fuse_bits_t8112[] = {
    {0x0490, 0x6238, 0, 0, 6},   {0x0490, 0x6220, 6, 14, 3},  {0x0490, 0x62a4, 12, 17, 2},
    {0x0490, 0x5018, 14, 2, 1},  {0x0490, 0x5220, 15, 14, 3}, {0x0490, 0x52a4, 18, 17, 2},
    {0x0490, 0x5278, 20, 20, 3}, {0x0490, 0x522c, 23, 12, 3}, {0x0490, 0x522c, 26, 9, 2},
    {0x0490, 0x522c, 28, 16, 4}, {0x0494, 0x522c, 0, 20, 1},  {0x0494, 0x1204, 5, 2, 5},
    {},
};
/* clang-format on */

static bool pcie_initialized = false;
static u64 rc_base;
static u64 phy_base;
static u64 phy_ip_base;
static u64 fuse_base;
static u32 port_count;
static u64 port_base[8];

#define SHARED_REG_COUNT 6

int pcie_init(void)
{
    const char *path = "/arm-io/apcie";
    int adt_path[8];
    int adt_offset;
    const struct fuse_bits *fuse_bits;

    if (pcie_initialized)
        return 0;

    adt_offset = adt_path_offset_trace(adt, path, adt_path);
    if (adt_offset < 0) {
        printf("pcie: Error getting node %s\n", path);
        return -1;
    }

    if (adt_is_compatible(adt, adt_offset, "apcie,t8103")) {
        fuse_bits = pcie_fuse_bits_t8103;
        printf("pcie: Initializing t8103 PCIe controller\n");
    } else if (adt_is_compatible(adt, adt_offset, "apcie,t6000")) {
        fuse_bits = pcie_fuse_bits_t6000;
        printf("pcie: Initializing t6000 PCIe controller\n");
    } else if (adt_is_compatible(adt, adt_offset, "apcie,t8112")) {
        fuse_bits = pcie_fuse_bits_t8112;
        printf("pcie: Initializing t8112 PCIe controller\n");
    } else {
        printf("pcie: Unsupported compatible\n");
        return -1;
    }

    if (ADT_GETPROP(adt, adt_offset, "#ports", &port_count) < 0) {
        printf("pcie: Error getting port count for %s\n", path);
        return -1;
    }

    u64 config_base;
    if (adt_get_reg(adt, adt_path, "reg", 0, &config_base, NULL)) {
        printf("pcie: Error getting reg with index %d for %s\n", 0, path);
        return -1;
    }

    if (adt_get_reg(adt, adt_path, "reg", 1, &rc_base, NULL)) {
        printf("pcie: Error getting reg with index %d for %s\n", 1, path);
        return -1;
    }

    if (adt_get_reg(adt, adt_path, "reg", 2, &phy_base, NULL)) {
        printf("pcie: Error getting reg with index %d for %s\n", 2, path);
        return -1;
    }

    if (adt_get_reg(adt, adt_path, "reg", 3, &phy_ip_base, NULL)) {
        printf("pcie: Error getting reg with index %d for %s\n", 3, path);
        return -1;
    }

    if (adt_get_reg(adt, adt_path, "reg", 5, &fuse_base, NULL)) {
        printf("pcie: Error getting reg with index %d for %s\n", 5, path);
        return -1;
    }

    u32 reg_len;
    if (!adt_getprop(adt, adt_offset, "reg", &reg_len)) {
        printf("pcie: Error getting reg length for %s\n", path);
        return -1;
    }

    int port_regs = (reg_len / 16) - SHARED_REG_COUNT;

    if (port_regs % port_count) {
        printf("pcie: %d port registers do not evenly divide into %d ports\n", port_regs,
               port_count);
        return -1;
    }

    int port_reg_cnt = port_regs / port_count;
    printf("pcie: ADT uses %d reg entries per port\n", port_reg_cnt);

    if (pmgr_adt_power_enable(path)) {
        printf("pcie: Error enabling power for %s\n", path);
        return -1;
    }

    if (tunables_apply_local(path, "apcie-axi2af-tunables", 4)) {
        printf("pcie: Error applying %s for %s\n", "apcie-axi2af-tunables", path);
        return -1;
    }

    /* ??? */
    write32(rc_base + 0x4, 0);

    if (tunables_apply_local(path, "apcie-common-tunables", 1)) {
        printf("pcie: Error applying %s for %s\n", "apcie-common-tunables", path);
        return -1;
    }

    /*
     * Initialize PHY.
     */

    if (tunables_apply_local(path, "apcie-phy-tunables", 2)) {
        printf("pcie: Error applying %s for %s\n", "apcie-phy-tunables", path);
        return -1;
    }

    set32(phy_base + APCIE_PHY_CTRL, APCIE_PHY_CTRL_CLK0REQ);
    if (poll32(phy_base + APCIE_PHY_CTRL, APCIE_PHY_CTRL_CLK0ACK, APCIE_PHY_CTRL_CLK0ACK, 50000)) {
        printf("pcie: Timeout enabling PHY CLK0\n");
        return -1;
    }

    set32(phy_base + APCIE_PHY_CTRL, APCIE_PHY_CTRL_CLK1REQ);
    if (poll32(phy_base + APCIE_PHY_CTRL, APCIE_PHY_CTRL_CLK1ACK, APCIE_PHY_CTRL_CLK1ACK, 50000)) {
        printf("pcie: Timeout enabling PHY CLK1\n");
        return -1;
    }

    clear32(phy_base + APCIE_PHY_CTRL, APCIE_PHY_CTRL_RESET);
    udelay(1);

    /* ??? */
    set32(rc_base + APCIE_PHYIF_CTRL, APCIE_PHYIF_CTRL_RUN);
    udelay(1);

    /* Apply "fuses". */
    for (int i = 0; fuse_bits[i].width; i++) {
        u32 fuse;
        fuse = (read32(fuse_base + fuse_bits[i].src_reg) >> fuse_bits[i].src_bit);
        fuse &= (1 << fuse_bits[i].width) - 1;
        mask32(phy_ip_base + fuse_bits[i].tgt_reg,
               ((1 << fuse_bits[i].width) - 1) << fuse_bits[i].tgt_bit,
               fuse << fuse_bits[i].tgt_bit);
    }

    if (tunables_apply_local(path, "apcie-phy-ip-pll-tunables", 3)) {
        printf("pcie: Error applying %s for %s\n", "apcie-phy-ip-pll-tunables", path);
        return -1;
    }
    if (tunables_apply_local(path, "apcie-phy-ip-auspma-tunables", 3)) {
        printf("pcie: Error applying %s for %s\n", "apcie-phy-ip-auspma-tunables", path);
        return -1;
    }

    for (u32 port = 0; port < port_count; port++) {
        char bridge[64];
        int bridge_offset;

        /*
         * Initialize RC port.
         */

        snprintf(bridge, sizeof(bridge), "/arm-io/apcie/pci-bridge%d", port);

        if ((bridge_offset = adt_path_offset(adt, bridge)) < 0)
            continue;

        printf("pcie: Initializing port %d\n", port);

        if (adt_get_reg(adt, adt_path, "reg", port * port_reg_cnt + SHARED_REG_COUNT,
                        &port_base[port], NULL)) {
            printf("pcie: Error getting reg with index %d for %s\n",
                   port * port_reg_cnt + SHARED_REG_COUNT, path);
            return -1;
        }

        if (tunables_apply_local_addr(bridge, "apcie-config-tunables", port_base[port])) {
            printf("pcie: Error applying %s for %s\n", "apcie-config-tunables", bridge);
            return -1;
        }

        set32(port_base[port] + APCIE_PORT_APPCLK, APCIE_PORT_APPCLK_EN);

        /* PERSTN */
        set32(port_base[port] + APCIE_PORT_RESET, APCIE_PORT_RESET_DIS);

        if (poll32(port_base[port] + APCIE_PORT_STATUS, APCIE_PORT_STATUS_RUN,
                   APCIE_PORT_STATUS_RUN, 250000)) {
            printf("pcie: Port failed to come up on %s\n", bridge);
            return -1;
        }

        if (poll32(port_base[port] + APCIE_PORT_LINKSTS, APCIE_PORT_LINKSTS_BUSY, 0, 250000)) {
            printf("pcie: Port failed to become idle on %s\n", bridge);
            return -1;
        }

        /* Make Designware PCIe Core registers writable. */
        set32(config_base + DWC_DBI_RO_WR, DWC_DBI_RO_WR_EN);

        if (tunables_apply_local_addr(bridge, "pcie-rc-tunables", config_base)) {
            printf("pcie: Error applying %s for %s\n", "pcie-rc-tunables", bridge);
            return -1;
        }
        if (tunables_apply_local_addr(bridge, "pcie-rc-gen3-shadow-tunables", config_base)) {
            printf("pcie: Error applying %s for %s\n", "pcie-rc-gen3-shadow-tunables", bridge);
            return -1;
        }
        if (tunables_apply_local_addr(bridge, "pcie-rc-gen4-shadow-tunables", config_base)) {
            printf("pcie: Error applying %s for %s\n", "pcie-rc-gen4-shadow-tunables", bridge);
            return -1;
        }

        u32 max_speed;
        if (ADT_GETPROP(adt, bridge_offset, "maximum-link-speed", &max_speed) >= 0) {
            /* Some devices override "maximum-link-speed" in the device child nodes.
             * The property used for the link speed seems to be ad-hoc made up.
             * The 10 GB ethernet adapter uses "target-link-speed" and the SD card
             * reader uses "expected-link-speed". Assume that PCIe link speed override
             * resides in the first (only?) child node.
             */
            if (max_speed == 1) {
                int np = adt_first_child_offset(adt, bridge_offset);
                if (np >= 0) {
                    int target_speed;
                    if (ADT_GETPROP(adt, np, "target-link-speed", &target_speed) >= 0 &&
                        target_speed > 0) {
                        max_speed = target_speed;
                    } else if (ADT_GETPROP(adt, np, "expected-link-speed", &target_speed) >= 0 &&
                               target_speed > 0) {
                        max_speed = target_speed;
                    }
                }
            }

            printf("pcie: Port %d max speed = %d\n", port, max_speed);

            if (max_speed == 0) {
                printf("pcie: Invalid max-speed\n");
                return -1;
            }

            mask32(config_base + PCIE_CAP_BASE + PCIE_LNKCAP, PCIE_LNKCAP_SLS,
                   FIELD_PREP(PCIE_LNKCAP_SLS, max_speed));

            mask32(config_base + PCIE_CAP_BASE + PCIE_LNKCAP2, PCIE_LNKCAP2_SLS,
                   FIELD_PREP(PCIE_LNKCAP2_SLS, (1 << max_speed) - 1));

            mask16(config_base + PCIE_CAP_BASE + PCIE_LNKCTL2, PCIE_LNKCTL2_TLS,
                   FIELD_PREP(PCIE_LNKCTL2_TLS, max_speed));
        }

        set32(config_base + DWC_DBI_LINK_WIDTH_SPEED_CONTROL, DWC_DBI_SPEED_CHANGE);

        /* Make Designware PCIe Core registers readonly. */
        clear32(config_base + DWC_DBI_RO_WR, DWC_DBI_RO_WR_EN);

        /* Move to the next PCIe device on this bus. */
        config_base += (1 << 15);
    }

    pcie_initialized = true;
    printf("pcie: Initialized.\n");

    return 0;
}

int pcie_shutdown(void)
{
    if (!pcie_initialized)
        return 0;

    for (u32 port = 0; port < port_count; port++) {
        clear32(port_base[port] + APCIE_PORT_RESET, APCIE_PORT_RESET_DIS);
        clear32(port_base[port] + APCIE_PORT_APPCLK, APCIE_PORT_APPCLK_EN);
    }

    clear32(phy_base + APCIE_PHY_CTRL, APCIE_PHY_CTRL_RESET);
    clear32(phy_base + APCIE_PHY_CTRL, APCIE_PHY_CTRL_CLK1REQ);
    clear32(phy_base + APCIE_PHY_CTRL, APCIE_PHY_CTRL_CLK0REQ);

    pcie_initialized = false;
    printf("pcie: Shutdown.\n");

    return 0;
}