// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <ddk/debug.h>
#include <ddk/device.h>
#include <ddk/driver.h>
#include <ddk/binding.h>

#include <byteswap.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/param.h>

#include <fbl/alloc_checker.h>
#include <lib/sync/completion.h>
#include <lib/zx/vmo.h>
#include <zircon/device/block.h>
#include <zircon/types.h>

#include "sata.h"

#define SATA_FLAG_DMA   (1 << 0)
#define SATA_FLAG_LBA48 (1 << 1)

struct sata_device_t {
    zx_device_t* zxdev = nullptr;
    AhciController* controller = nullptr;

    block_info_t info{};

    uint32_t port = 0;
    uint32_t flags = 0;
    uint32_t max_cmd = 0; // inclusive
};

// Strings are byte-flipped in pairs.
void string_fix(uint16_t* buf, size_t size) {
    for (size_t i = 0; i < (size / 2); i++) {
        buf[i] = bswap_16(buf[i]);
    }
}

static void sata_device_identify_complete(void* cookie, zx_status_t status, block_op_t* op) {
    sata_txn_t* txn = containerof(op, sata_txn_t, bop);
    txn->status = status;
    sync_completion_signal(static_cast<sync_completion_t*>(cookie));
}

#define QEMU_MODEL_ID    "QEMU HARDDISK"
#define QEMU_SG_MAX      1024             // Linux kernel limit

static bool model_id_is_qemu(char* model_id) {
    return !memcmp(model_id, QEMU_MODEL_ID, sizeof(QEMU_MODEL_ID)-1);
}

static zx_status_t sata_device_identify(sata_device_t* dev, AhciController* controller,
                                        const char* name) {
    // Set default devinfo
    sata_devinfo_t di;
    di.block_size = 512;
    di.max_cmd = 1;
    ahci_set_devinfo(controller, dev->port, &di);

    // send IDENTIFY DEVICE
    zx::vmo vmo;
    zx_status_t status = zx::vmo::create(512, 0, &vmo);
    if (status != ZX_OK) {
        zxlogf(TRACE, "sata: error %d allocating vmo\n", status);
        return status;
    }

    sync_completion_t completion;
    sata_txn_t txn = {};
    txn.bop.rw.vmo = vmo.get();
    txn.bop.rw.length = 1;
    txn.bop.rw.offset_dev = 0;
    txn.bop.rw.offset_vmo = 0;
    txn.cmd = SATA_CMD_IDENTIFY_DEVICE;
    txn.device = 0;
    txn.completion_cb = sata_device_identify_complete;
    txn.cookie = &completion;

    ahci_queue(controller, dev->port, &txn);
    sync_completion_wait(&completion, ZX_TIME_INFINITE);

    if (txn.status != ZX_OK) {
        zxlogf(ERROR, "%s: error %d in device identify\n", name, txn.status);
        return txn.status;
    }

    // parse results
    int flags = 0;
    sata_devinfo_response_t devinfo;
    status = vmo.read(&devinfo, 0, sizeof(devinfo));
    if (status != ZX_OK) {
        zxlogf(ERROR, "sata: error %d in vmo_read\n", status);
        return ZX_ERR_INTERNAL;
    }
    vmo.reset();

    // Strings are 16-bit byte-flipped. Fix in place.
    // Strings are NOT null-terminated.
    string_fix(devinfo.serial.word, sizeof(devinfo.serial.word));
    string_fix(devinfo.firmware_rev.word, sizeof(devinfo.firmware_rev.word));
    string_fix(devinfo.model_id.word, sizeof(devinfo.model_id.word));

    zxlogf(INFO, "%s: dev info\n", name);
    zxlogf(INFO, "  serial=%.*s\n", SATA_DEVINFO_SERIAL_LEN, devinfo.serial.string);
    zxlogf(INFO, "  firmware rev=%.*s\n", SATA_DEVINFO_FW_REV_LEN, devinfo.firmware_rev.string);
    zxlogf(INFO, "  model id=%.*s\n", SATA_DEVINFO_MODEL_ID_LEN, devinfo.model_id.string);

    bool is_qemu = model_id_is_qemu(devinfo.model_id.string);

    uint16_t major = devinfo.major_version;
    zxlogf(INFO, "  major=0x%x ", major);
    switch (32 - __builtin_clz(major) - 1) {
    case 11:
        zxlogf(INFO, "ACS4");
        break;
    case 10:
        zxlogf(INFO, "ACS3");
        break;
    case 9:
        zxlogf(INFO, "ACS2");
        break;
    case 8:
        zxlogf(INFO, "ATA8-ACS");
        break;
    case 7:
    case 6:
    case 5:
        zxlogf(INFO, "ATA/ATAPI");
        break;
    default:
        zxlogf(INFO, "Obsolete");
        break;
    }

    uint16_t cap = devinfo.capabilities_1;
    if (cap & (1 << 8)) {
        zxlogf(INFO, " DMA");
        flags |= SATA_FLAG_DMA;
    } else {
        zxlogf(INFO, " PIO");
    }
    dev->max_cmd = devinfo.queue_depth;
    zxlogf(INFO, " %u commands\n", dev->max_cmd + 1);

    uint32_t block_size = 512; // default
    uint64_t block_count = 0;
    if (cap & (1 << 9)) {
        if ((devinfo.sector_size & 0xd000) == 0x5000) {
            block_size = 2 * devinfo.logical_sector_size;
        }
        if (devinfo.command_set1_1 & (1 << 10)) {
            flags |= SATA_FLAG_LBA48;
            block_count = devinfo.lba_capacity2;
            zxlogf(INFO, "  LBA48");
        } else {
            block_count = devinfo.lba_capacity;
            zxlogf(INFO, "  LBA");
        }
        zxlogf(INFO, " %" PRIu64 " sectors,  sector size=%u\n", block_count, block_size);
    } else {
        zxlogf(INFO, "  CHS unsupported!\n");
    }
    dev->flags = flags;

    memset(&dev->info, 0, sizeof(dev->info));
    dev->info.block_size = block_size;
    dev->info.block_count = block_count;

    uint32_t max_sg_size = SATA_MAX_BLOCK_COUNT * block_size; // SATA cmd limit
    if (is_qemu) {
        max_sg_size = MIN(max_sg_size, QEMU_SG_MAX * block_size);
    }
    dev->info.max_transfer_size = MIN(AHCI_MAX_BYTES, max_sg_size);

    // set devinfo on controller
    di.block_size = block_size,
    di.max_cmd = dev->max_cmd,

    ahci_set_devinfo(controller, dev->port, &di);

    return ZX_OK;
}

// implement device protocol:

static zx_off_t sata_getsize(void* ctx) {
    sata_device_t* device = static_cast<sata_device_t*>(ctx);
    return device->info.block_count * device->info.block_size;
}

static void sata_release(void* ctx) {
    sata_device_t* device = static_cast<sata_device_t*>(ctx);
    delete device;
}

static zx_protocol_device_t sata_device_proto = []() {
    zx_protocol_device_t device;
    device.version = DEVICE_OPS_VERSION;
    device.get_size = sata_getsize;
    device.release = sata_release;
    return device;
}();

static void sata_query(void* ctx, block_info_t* info_out, size_t* block_op_size_out) {
    sata_device_t* dev = static_cast<sata_device_t*>(ctx);
    memcpy(info_out, &dev->info, sizeof(*info_out));
    *block_op_size_out = sizeof(sata_txn_t);
}

static void sata_queue(void* ctx, block_op_t* bop, block_impl_queue_callback completion_cb,
                       void* cookie) {
    sata_device_t* dev = static_cast<sata_device_t*>(ctx);
    sata_txn_t* txn = containerof(bop, sata_txn_t, bop);
    txn->completion_cb = completion_cb;
    txn->cookie = cookie;

    switch (BLOCK_OP(bop->command)) {
    case BLOCK_OP_READ:
    case BLOCK_OP_WRITE:
        // complete empty transactions immediately
        if (bop->rw.length == 0) {
            block_complete(txn, ZX_ERR_INVALID_ARGS);
            return;
        }
        // transaction must fit within device
        if ((bop->rw.offset_dev >= dev->info.block_count) ||
            ((dev->info.block_count - bop->rw.offset_dev) < bop->rw.length)) {
            block_complete(txn, ZX_ERR_OUT_OF_RANGE);
            return;
        }

        txn->cmd = (BLOCK_OP(bop->command) == BLOCK_OP_READ) ?
                   SATA_CMD_READ_DMA_EXT : SATA_CMD_WRITE_DMA_EXT;
        txn->device = 0x40;
        zxlogf(TRACE, "sata: queue op 0x%x txn %p\n", bop->command, txn);
        break;
    case BLOCK_OP_FLUSH:
        zxlogf(TRACE, "sata: queue FLUSH txn %p\n", txn);
        break;
    default:
        block_complete(txn, ZX_ERR_NOT_SUPPORTED);
        return;
    }

    ahci_queue(dev->controller, dev->port, txn);
}

static block_impl_protocol_ops_t sata_block_proto = {
    .query = sata_query,
    .queue = sata_queue,
};

zx_status_t sata_bind(AhciController* controller, zx_device_t* parent, uint32_t port) {
    // initialize the device
    fbl::AllocChecker ac;
    std::unique_ptr<sata_device_t> device(new (&ac) sata_device_t);
    if (!ac.check()) {
        zxlogf(ERROR, "sata: out of memory\n");
        return ZX_ERR_NO_MEMORY;
    }
    device->controller = controller;
    device->port = port;

    char name[8];
    snprintf(name, sizeof(name), "sata%u", port);

    // send device identify
    zx_status_t status = sata_device_identify(device.get(), controller, name);
    if (status < 0) {
        return status;
    }

    // add the device
    device_add_args_t args = {};
    args.version = DEVICE_ADD_ARGS_VERSION;
    args.name = name;
    args.ctx = device.get();
    args.ops = &sata_device_proto;
    args.proto_id = ZX_PROTOCOL_BLOCK_IMPL;
    args.proto_ops = &sata_block_proto;

    status = device_add(parent, &args, &device->zxdev);
    if (status < 0) {
        return status;
    }
    device.release(); // Device has been retained by device_add().
    return ZX_OK;
}