// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2017 NXP Semiconductors
 * Copyright (C) 2017 Bin Meng <bmeng.cn@gmail.com>
 */

#include <common.h>
#include <blk.h>
#include <cpu_func.h>
#include <dm.h>
#include <errno.h>
#include <log.h>
#include <malloc.h>
#include <memalign.h>
#include <pci.h>
#include <time.h>
#include <dm/device-internal.h>
#include <linux/compat.h>
#include "nvme.h"

#define NVME_Q_DEPTH            2
#define NVME_AQ_DEPTH           2
#define NVME_SQ_SIZE(depth)     (depth * sizeof(struct nvme_command))
#define NVME_CQ_SIZE(depth)     (depth * sizeof(struct nvme_completion))
#define ADMIN_TIMEOUT           60
#define IO_TIMEOUT              30
#define MAX_PRP_POOL            512

enum nvme_queue_id {
        NVME_ADMIN_Q,
        NVME_IO_Q,
        NVME_Q_NUM,
};

/*
 * An NVM Express queue. Each device has at least two (one for admin
 * commands and one for I/O commands).
 */
struct nvme_queue {
        struct nvme_dev *dev;
        struct nvme_command *sq_cmds;
        struct nvme_completion *cqes;
        wait_queue_head_t sq_full;
        u32 __iomem *q_db;
        u16 q_depth;
        s16 cq_vector;
        u16 sq_head;
        u16 sq_tail;
        u16 cq_head;
        u16 qid;
        u8 cq_phase;
        u8 cqe_seen;
        unsigned long cmdid_data[];
};

static int nvme_wait_ready(struct nvme_dev *dev, bool enabled)
{
        u32 bit = enabled ? NVME_CSTS_RDY : 0;
        int timeout;
        ulong start;

        /* Timeout field in the CAP register is in 500 millisecond units */
        timeout = NVME_CAP_TIMEOUT(dev->cap) * 500;

        start = get_timer(0);
        while (get_timer(start) < timeout) {
                if ((readl(&dev->bar->csts) & NVME_CSTS_RDY) == bit)
                        return 0;
        }

        return -ETIME;
}

static int nvme_setup_prps(struct nvme_dev *dev, u64 *prp2,
                           int total_len, u64 dma_addr)
{
        u32 page_size = dev->page_size;
        int offset = dma_addr & (page_size - 1);
        u64 *prp_pool;
        int length = total_len;
        int i, nprps;
        u32 prps_per_page = (page_size >> 3) - 1;
        u32 num_pages;

        length -= (page_size - offset);

        if (length <= 0) {
                *prp2 = 0;
                return 0;
        }

        if (length)
                dma_addr += (page_size - offset);

        if (length <= page_size) {
                *prp2 = dma_addr;
                return 0;
        }

        nprps = DIV_ROUND_UP(length, page_size);
        num_pages = DIV_ROUND_UP(nprps, prps_per_page);

        if (nprps > dev->prp_entry_num) {
                free(dev->prp_pool);
                /*
                 * Always increase in increments of pages.  It doesn't waste
                 * much memory and reduces the number of allocations.
                 */
                dev->prp_pool = memalign(page_size, num_pages * page_size);
                if (!dev->prp_pool) {
                        printf("Error: malloc prp_pool fail\n");
                        return -ENOMEM;
                }
                dev->prp_entry_num = prps_per_page * num_pages;
        }

        prp_pool = dev->prp_pool;
        i = 0;
        while (nprps) {
                if (i == ((page_size >> 3) - 1)) {
                        *(prp_pool + i) = cpu_to_le64((ulong)prp_pool +
                                        page_size);
                        i = 0;
                        prp_pool += page_size;
                }
                *(prp_pool + i++) = cpu_to_le64(dma_addr);
                dma_addr += page_size;
                nprps--;
        }
        *prp2 = (ulong)dev->prp_pool;

        flush_dcache_range((ulong)dev->prp_pool, (ulong)dev->prp_pool +
                           dev->prp_entry_num * sizeof(u64));

        return 0;
}

static __le16 nvme_get_cmd_id(void)
{
        static unsigned short cmdid;

        return cpu_to_le16((cmdid < USHRT_MAX) ? cmdid++ : 0);
}

static u16 nvme_read_completion_status(struct nvme_queue *nvmeq, u16 index)
{
        u64 start = (ulong)&nvmeq->cqes[index];
        u64 stop = start + sizeof(struct nvme_completion);

        invalidate_dcache_range(start, stop);

        return le16_to_cpu(readw(&(nvmeq->cqes[index].status)));
}

/**
 * nvme_submit_cmd() - copy a command into a queue and ring the doorbell
 *
 * @nvmeq:      The queue to use
 * @cmd:        The command to send
 */
static void nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd)
{
        u16 tail = nvmeq->sq_tail;

        memcpy(&nvmeq->sq_cmds[tail], cmd, sizeof(*cmd));
        flush_dcache_range((ulong)&nvmeq->sq_cmds[tail],
                           (ulong)&nvmeq->sq_cmds[tail] + sizeof(*cmd));

        if (++tail == nvmeq->q_depth)
                tail = 0;
        writel(tail, nvmeq->q_db);
        nvmeq->sq_tail = tail;
}

static int nvme_submit_sync_cmd(struct nvme_queue *nvmeq,
                                struct nvme_command *cmd,
                                u32 *result, unsigned timeout)
{
        u16 head = nvmeq->cq_head;
        u16 phase = nvmeq->cq_phase;
        u16 status;
        ulong start_time;
        ulong timeout_us = timeout * 100000;

        cmd->common.command_id = nvme_get_cmd_id();
        nvme_submit_cmd(nvmeq, cmd);

        start_time = timer_get_us();

        for (;;) {
                status = nvme_read_completion_status(nvmeq, head);
                if ((status & 0x01) == phase)
                        break;
                if (timeout_us > 0 && (timer_get_us() - start_time)
                    >= timeout_us)
                        return -ETIMEDOUT;
        }

        status >>= 1;
        if (status) {
                printf("ERROR: status = %x, phase = %d, head = %d\n",
                       status, phase, head);
                status = 0;
                if (++head == nvmeq->q_depth) {
                        head = 0;
                        phase = !phase;
                }
                writel(head, nvmeq->q_db + nvmeq->dev->db_stride);
                nvmeq->cq_head = head;
                nvmeq->cq_phase = phase;

                return -EIO;
        }

        if (result)
                *result = le32_to_cpu(readl(&(nvmeq->cqes[head].result)));

        if (++head == nvmeq->q_depth) {
                head = 0;
                phase = !phase;
        }
        writel(head, nvmeq->q_db + nvmeq->dev->db_stride);
        nvmeq->cq_head = head;
        nvmeq->cq_phase = phase;

        return status;
}

static int nvme_submit_admin_cmd(struct nvme_dev *dev, struct nvme_command *cmd,
                                 u32 *result)
{
        return nvme_submit_sync_cmd(dev->queues[NVME_ADMIN_Q], cmd,
                                    result, ADMIN_TIMEOUT);
}

static struct nvme_queue *nvme_alloc_queue(struct nvme_dev *dev,
                                           int qid, int depth)
{
        struct nvme_queue *nvmeq = malloc(sizeof(*nvmeq));
        if (!nvmeq)
                return NULL;
        memset(nvmeq, 0, sizeof(*nvmeq));

        nvmeq->cqes = (void *)memalign(4096, NVME_CQ_SIZE(depth));
        if (!nvmeq->cqes)
                goto free_nvmeq;
        memset((void *)nvmeq->cqes, 0, NVME_CQ_SIZE(depth));

        nvmeq->sq_cmds = (void *)memalign(4096, NVME_SQ_SIZE(depth));
        if (!nvmeq->sq_cmds)
                goto free_queue;
        memset((void *)nvmeq->sq_cmds, 0, NVME_SQ_SIZE(depth));

        nvmeq->dev = dev;

        nvmeq->cq_head = 0;
        nvmeq->cq_phase = 1;
        nvmeq->q_db = &dev->dbs[qid * 2 * dev->db_stride];
        nvmeq->q_depth = depth;
        nvmeq->qid = qid;
        dev->queue_count++;
        dev->queues[qid] = nvmeq;

        return nvmeq;

 free_queue:
        free((void *)nvmeq->cqes);
 free_nvmeq:
        free(nvmeq);

        return NULL;
}

static int nvme_delete_queue(struct nvme_dev *dev, u8 opcode, u16 id)
{
        struct nvme_command c;

        memset(&c, 0, sizeof(c));
        c.delete_queue.opcode = opcode;
        c.delete_queue.qid = cpu_to_le16(id);

        return nvme_submit_admin_cmd(dev, &c, NULL);
}

static int nvme_delete_sq(struct nvme_dev *dev, u16 sqid)
{
        return nvme_delete_queue(dev, nvme_admin_delete_sq, sqid);
}

static int nvme_delete_cq(struct nvme_dev *dev, u16 cqid)
{
        return nvme_delete_queue(dev, nvme_admin_delete_cq, cqid);
}

static int nvme_enable_ctrl(struct nvme_dev *dev)
{
        dev->ctrl_config &= ~NVME_CC_SHN_MASK;
        dev->ctrl_config |= NVME_CC_ENABLE;
        writel(cpu_to_le32(dev->ctrl_config), &dev->bar->cc);

        return nvme_wait_ready(dev, true);
}

static int nvme_disable_ctrl(struct nvme_dev *dev)
{
        dev->ctrl_config &= ~NVME_CC_SHN_MASK;
        dev->ctrl_config &= ~NVME_CC_ENABLE;
        writel(cpu_to_le32(dev->ctrl_config), &dev->bar->cc);

        return nvme_wait_ready(dev, false);
}

static void nvme_free_queue(struct nvme_queue *nvmeq)
{
        free((void *)nvmeq->cqes);
        free(nvmeq->sq_cmds);
        free(nvmeq);
}

static void nvme_free_queues(struct nvme_dev *dev, int lowest)
{
        int i;

        for (i = dev->queue_count - 1; i >= lowest; i--) {
                struct nvme_queue *nvmeq = dev->queues[i];
                dev->queue_count--;
                dev->queues[i] = NULL;
                nvme_free_queue(nvmeq);
        }
}

static void nvme_init_queue(struct nvme_queue *nvmeq, u16 qid)
{
        struct nvme_dev *dev = nvmeq->dev;

        nvmeq->sq_tail = 0;
        nvmeq->cq_head = 0;
        nvmeq->cq_phase = 1;
        nvmeq->q_db = &dev->dbs[qid * 2 * dev->db_stride];
        memset((void *)nvmeq->cqes, 0, NVME_CQ_SIZE(nvmeq->q_depth));
        flush_dcache_range((ulong)nvmeq->cqes,
                           (ulong)nvmeq->cqes + NVME_CQ_SIZE(nvmeq->q_depth));
        dev->online_queues++;
}

static int nvme_configure_admin_queue(struct nvme_dev *dev)
{
        int result;
        u32 aqa;
        u64 cap = dev->cap;
        struct nvme_queue *nvmeq;
        /* most architectures use 4KB as the page size */
        unsigned page_shift = 12;
        unsigned dev_page_min = NVME_CAP_MPSMIN(cap) + 12;
        unsigned dev_page_max = NVME_CAP_MPSMAX(cap) + 12;

        if (page_shift < dev_page_min) {
                debug("Device minimum page size (%u) too large for host (%u)\n",
                      1 << dev_page_min, 1 << page_shift);
                return -ENODEV;
        }

        if (page_shift > dev_page_max) {
                debug("Device maximum page size (%u) smaller than host (%u)\n",
                      1 << dev_page_max, 1 << page_shift);
                page_shift = dev_page_max;
        }

        result = nvme_disable_ctrl(dev);
        if (result < 0)
                return result;

        nvmeq = dev->queues[NVME_ADMIN_Q];
        if (!nvmeq) {
                nvmeq = nvme_alloc_queue(dev, 0, NVME_AQ_DEPTH);
                if (!nvmeq)
                        return -ENOMEM;
        }

        aqa = nvmeq->q_depth - 1;
        aqa |= aqa << 16;
        aqa |= aqa << 16;

        dev->page_size = 1 << page_shift;

        dev->ctrl_config = NVME_CC_CSS_NVM;
        dev->ctrl_config |= (page_shift - 12) << NVME_CC_MPS_SHIFT;
        dev->ctrl_config |= NVME_CC_ARB_RR | NVME_CC_SHN_NONE;
        dev->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;

        writel(aqa, &dev->bar->aqa);
        nvme_writeq((ulong)nvmeq->sq_cmds, &dev->bar->asq);
        nvme_writeq((ulong)nvmeq->cqes, &dev->bar->acq);

        result = nvme_enable_ctrl(dev);
        if (result)
                goto free_nvmeq;

        nvmeq->cq_vector = 0;

        nvme_init_queue(dev->queues[NVME_ADMIN_Q], 0);

        return result;

 free_nvmeq:
        nvme_free_queues(dev, 0);

        return result;
}

static int nvme_alloc_cq(struct nvme_dev *dev, u16 qid,
                            struct nvme_queue *nvmeq)
{
        struct nvme_command c;
        int flags = NVME_QUEUE_PHYS_CONTIG | NVME_CQ_IRQ_ENABLED;

        memset(&c, 0, sizeof(c));
        c.create_cq.opcode = nvme_admin_create_cq;
        c.create_cq.prp1 = cpu_to_le64((ulong)nvmeq->cqes);
        c.create_cq.cqid = cpu_to_le16(qid);
        c.create_cq.qsize = cpu_to_le16(nvmeq->q_depth - 1);
        c.create_cq.cq_flags = cpu_to_le16(flags);
        c.create_cq.irq_vector = cpu_to_le16(nvmeq->cq_vector);

        return nvme_submit_admin_cmd(dev, &c, NULL);
}

static int nvme_alloc_sq(struct nvme_dev *dev, u16 qid,
                            struct nvme_queue *nvmeq)
{
        struct nvme_command c;
        int flags = NVME_QUEUE_PHYS_CONTIG | NVME_SQ_PRIO_MEDIUM;

        memset(&c, 0, sizeof(c));
        c.create_sq.opcode = nvme_admin_create_sq;
        c.create_sq.prp1 = cpu_to_le64((ulong)nvmeq->sq_cmds);
        c.create_sq.sqid = cpu_to_le16(qid);
        c.create_sq.qsize = cpu_to_le16(nvmeq->q_depth - 1);
        c.create_sq.sq_flags = cpu_to_le16(flags);
        c.create_sq.cqid = cpu_to_le16(qid);

        return nvme_submit_admin_cmd(dev, &c, NULL);
}

int nvme_identify(struct nvme_dev *dev, unsigned nsid,
                  unsigned cns, dma_addr_t dma_addr)
{
        struct nvme_command c;
        u32 page_size = dev->page_size;
        int offset = dma_addr & (page_size - 1);
        int length = sizeof(struct nvme_id_ctrl);
        int ret;

        memset(&c, 0, sizeof(c));
        c.identify.opcode = nvme_admin_identify;
        c.identify.nsid = cpu_to_le32(nsid);
        c.identify.prp1 = cpu_to_le64(dma_addr);

        length -= (page_size - offset);
        if (length <= 0) {
                c.identify.prp2 = 0;
        } else {
                dma_addr += (page_size - offset);
                c.identify.prp2 = cpu_to_le64(dma_addr);
        }

        c.identify.cns = cpu_to_le32(cns);

        invalidate_dcache_range(dma_addr,
                                dma_addr + sizeof(struct nvme_id_ctrl));

        ret = nvme_submit_admin_cmd(dev, &c, NULL);
        if (!ret)
                invalidate_dcache_range(dma_addr,
                                        dma_addr + sizeof(struct nvme_id_ctrl));

        return ret;
}

int nvme_get_features(struct nvme_dev *dev, unsigned fid, unsigned nsid,
                      dma_addr_t dma_addr, u32 *result)
{
        struct nvme_command c;

        memset(&c, 0, sizeof(c));
        c.features.opcode = nvme_admin_get_features;
        c.features.nsid = cpu_to_le32(nsid);
        c.features.prp1 = cpu_to_le64(dma_addr);
        c.features.fid = cpu_to_le32(fid);

        /*
         * TODO: add cache invalidate operation when the size of
         * the DMA buffer is known
         */

        return nvme_submit_admin_cmd(dev, &c, result);
}

int nvme_set_features(struct nvme_dev *dev, unsigned fid, unsigned dword11,
                      dma_addr_t dma_addr, u32 *result)
{
        struct nvme_command c;

        memset(&c, 0, sizeof(c));
        c.features.opcode = nvme_admin_set_features;
        c.features.prp1 = cpu_to_le64(dma_addr);
        c.features.fid = cpu_to_le32(fid);
        c.features.dword11 = cpu_to_le32(dword11);

        /*
         * TODO: add cache flush operation when the size of
         * the DMA buffer is known
         */

        return nvme_submit_admin_cmd(dev, &c, result);
}

static int nvme_create_queue(struct nvme_queue *nvmeq, int qid)
{
        struct nvme_dev *dev = nvmeq->dev;
        int result;

        nvmeq->cq_vector = qid - 1;
        result = nvme_alloc_cq(dev, qid, nvmeq);
        if (result < 0)
                goto release_cq;

        result = nvme_alloc_sq(dev, qid, nvmeq);
        if (result < 0)
                goto release_sq;

        nvme_init_queue(nvmeq, qid);

        return result;

 release_sq:
        nvme_delete_sq(dev, qid);
 release_cq:
        nvme_delete_cq(dev, qid);

        return result;
}

static int nvme_set_queue_count(struct nvme_dev *dev, int count)
{
        int status;
        u32 result;
        u32 q_count = (count - 1) | ((count - 1) << 16);

        status = nvme_set_features(dev, NVME_FEAT_NUM_QUEUES,
                        q_count, 0, &result);

        if (status < 0)
                return status;
        if (status > 1)
                return 0;

        return min(result & 0xffff, result >> 16) + 1;
}

static void nvme_create_io_queues(struct nvme_dev *dev)
{
        unsigned int i;

        for (i = dev->queue_count; i <= dev->max_qid; i++)
                if (!nvme_alloc_queue(dev, i, dev->q_depth))
                        break;

        for (i = dev->online_queues; i <= dev->queue_count - 1; i++)
                if (nvme_create_queue(dev->queues[i], i))
                        break;
}

static int nvme_setup_io_queues(struct nvme_dev *dev)
{
        int nr_io_queues;
        int result;

        nr_io_queues = 1;
        result = nvme_set_queue_count(dev, nr_io_queues);
        if (result <= 0)
                return result;

        dev->max_qid = nr_io_queues;

        /* Free previously allocated queues */
        nvme_free_queues(dev, nr_io_queues + 1);
        nvme_create_io_queues(dev);

        return 0;
}

static int nvme_get_info_from_identify(struct nvme_dev *dev)
{
        struct nvme_id_ctrl *ctrl;
        int ret;
        int shift = NVME_CAP_MPSMIN(dev->cap) + 12;

        ctrl = memalign(dev->page_size, sizeof(struct nvme_id_ctrl));
        if (!ctrl)
                return -ENOMEM;

        ret = nvme_identify(dev, 0, 1, (dma_addr_t)(long)ctrl);
        if (ret) {
                free(ctrl);
                return -EIO;
        }

        dev->nn = le32_to_cpu(ctrl->nn);
        dev->vwc = ctrl->vwc;
        memcpy(dev->serial, ctrl->sn, sizeof(ctrl->sn));
        memcpy(dev->model, ctrl->mn, sizeof(ctrl->mn));
        memcpy(dev->firmware_rev, ctrl->fr, sizeof(ctrl->fr));
        if (ctrl->mdts)
                dev->max_transfer_shift = (ctrl->mdts + shift);
        else {
                /*
                 * Maximum Data Transfer Size (MDTS) field indicates the maximum
                 * data transfer size between the host and the controller. The
                 * host should not submit a command that exceeds this transfer
                 * size. The value is in units of the minimum memory page size
                 * and is reported as a power of two (2^n).
                 *
                 * The spec also says: a value of 0h indicates no restrictions
                 * on transfer size. But in nvme_blk_read/write() below we have
                 * the following algorithm for maximum number of logic blocks
                 * per transfer:
                 *
                 * u16 lbas = 1 << (dev->max_transfer_shift - ns->lba_shift);
                 *
                 * In order for lbas not to overflow, the maximum number is 15
                 * which means dev->max_transfer_shift = 15 + 9 (ns->lba_shift).
                 * Let's use 20 which provides 1MB size.
                 */
                dev->max_transfer_shift = 20;
        }

        free(ctrl);
        return 0;
}

int nvme_get_namespace_id(struct udevice *udev, u32 *ns_id, u8 *eui64)
{
        struct nvme_ns *ns = dev_get_priv(udev);

        if (ns_id)
                *ns_id = ns->ns_id;
        if (eui64)
                memcpy(eui64, ns->eui64, sizeof(ns->eui64));

        return 0;
}

int nvme_scan_namespace(void)
{
        struct uclass *uc;
        struct udevice *dev;
        int ret;

        ret = uclass_get(UCLASS_NVME, &uc);
        if (ret)
                return ret;

        uclass_foreach_dev(dev, uc) {
                ret = device_probe(dev);
                if (ret)
                        return ret;
        }

        return 0;
}

static int nvme_blk_probe(struct udevice *udev)
{
        struct nvme_dev *ndev = dev_get_priv(udev->parent);
        struct blk_desc *desc = dev_get_uclass_platdata(udev);
        struct nvme_ns *ns = dev_get_priv(udev);
        u8 flbas;
        struct pci_child_platdata *pplat;
        struct nvme_id_ns *id;

        id = memalign(ndev->page_size, sizeof(struct nvme_id_ns));
        if (!id)
                return -ENOMEM;

        memset(ns, 0, sizeof(*ns));
        ns->dev = ndev;
        /* extract the namespace id from the block device name */
        ns->ns_id = trailing_strtol(udev->name) + 1;
        if (nvme_identify(ndev, ns->ns_id, 0, (dma_addr_t)(long)id)) {
                free(id);
                return -EIO;
        }

        memcpy(&ns->eui64, &id->eui64, sizeof(id->eui64));
        flbas = id->flbas & NVME_NS_FLBAS_LBA_MASK;
        ns->flbas = flbas;
        ns->lba_shift = id->lbaf[flbas].ds;
        ns->mode_select_num_blocks = le64_to_cpu(id->nsze);
        ns->mode_select_block_len = 1 << ns->lba_shift;
        list_add(&ns->list, &ndev->namespaces);

        desc->lba = ns->mode_select_num_blocks;
        desc->log2blksz = ns->lba_shift;
        desc->blksz = 1 << ns->lba_shift;
        desc->bdev = udev;
        pplat = dev_get_parent_platdata(udev->parent);
        sprintf(desc->vendor, "0x%.4x", pplat->vendor);
        memcpy(desc->product, ndev->serial, sizeof(ndev->serial));
        memcpy(desc->revision, ndev->firmware_rev, sizeof(ndev->firmware_rev));

        free(id);
        return 0;
}

static ulong nvme_blk_rw(struct udevice *udev, lbaint_t blknr,
                         lbaint_t blkcnt, void *buffer, bool read)
{
        struct nvme_ns *ns = dev_get_priv(udev);
        struct nvme_dev *dev = ns->dev;
        struct nvme_command c;
        struct blk_desc *desc = dev_get_uclass_platdata(udev);
        int status;
        u64 prp2;
        u64 total_len = blkcnt << desc->log2blksz;
        u64 temp_len = total_len;

        u64 slba = blknr;
        u16 lbas = 1 << (dev->max_transfer_shift - ns->lba_shift);
        u64 total_lbas = blkcnt;

        flush_dcache_range((unsigned long)buffer,
                           (unsigned long)buffer + total_len);

        c.rw.opcode = read ? nvme_cmd_read : nvme_cmd_write;
        c.rw.flags = 0;
        c.rw.nsid = cpu_to_le32(ns->ns_id);
        c.rw.control = 0;
        c.rw.dsmgmt = 0;
        c.rw.reftag = 0;
        c.rw.apptag = 0;
        c.rw.appmask = 0;
        c.rw.metadata = 0;

        while (total_lbas) {
                if (total_lbas < lbas) {
                        lbas = (u16)total_lbas;
                        total_lbas = 0;
                } else {
                        total_lbas -= lbas;
                }

                if (nvme_setup_prps(dev, &prp2,
                                    lbas << ns->lba_shift, (ulong)buffer))
                        return -EIO;
                c.rw.slba = cpu_to_le64(slba);
                slba += lbas;
                c.rw.length = cpu_to_le16(lbas - 1);
                c.rw.prp1 = cpu_to_le64((ulong)buffer);
                c.rw.prp2 = cpu_to_le64(prp2);
                status = nvme_submit_sync_cmd(dev->queues[NVME_IO_Q],
                                &c, NULL, IO_TIMEOUT);
                if (status)
                        break;
                temp_len -= (u32)lbas << ns->lba_shift;
                buffer += lbas << ns->lba_shift;
        }

        if (read)
                invalidate_dcache_range((unsigned long)buffer,
                                        (unsigned long)buffer + total_len);

        return (total_len - temp_len) >> desc->log2blksz;
}

static ulong nvme_blk_read(struct udevice *udev, lbaint_t blknr,
                           lbaint_t blkcnt, void *buffer)
{
        return nvme_blk_rw(udev, blknr, blkcnt, buffer, true);
}

static ulong nvme_blk_write(struct udevice *udev, lbaint_t blknr,
                            lbaint_t blkcnt, const void *buffer)
{
        return nvme_blk_rw(udev, blknr, blkcnt, (void *)buffer, false);
}

static const struct blk_ops nvme_blk_ops = {
        .read   = nvme_blk_read,
        .write  = nvme_blk_write,
};

U_BOOT_DRIVER(nvme_blk) = {
        .name   = "nvme-blk",
        .id     = UCLASS_BLK,
        .probe  = nvme_blk_probe,
        .ops    = &nvme_blk_ops,
        .priv_auto_alloc_size = sizeof(struct nvme_ns),
};

static int nvme_bind(struct udevice *udev)
{
        static int ndev_num;
        char name[20];

        sprintf(name, "nvme#%d", ndev_num++);

        return device_set_name(udev, name);
}

static int nvme_probe(struct udevice *udev)
{
        int ret;
        struct nvme_dev *ndev = dev_get_priv(udev);

        ndev->instance = trailing_strtol(udev->name);

        INIT_LIST_HEAD(&ndev->namespaces);
        ndev->bar = dm_pci_map_bar(udev, PCI_BASE_ADDRESS_0,
                        PCI_REGION_MEM);
        if (readl(&ndev->bar->csts) == -1) {
                ret = -ENODEV;
                printf("Error: %s: Out of memory!\n", udev->name);
                goto free_nvme;
        }

        ndev->queues = malloc(NVME_Q_NUM * sizeof(struct nvme_queue *));
        if (!ndev->queues) {
                ret = -ENOMEM;
                printf("Error: %s: Out of memory!\n", udev->name);
                goto free_nvme;
        }
        memset(ndev->queues, 0, NVME_Q_NUM * sizeof(struct nvme_queue *));

        ndev->cap = nvme_readq(&ndev->bar->cap);
        ndev->q_depth = min_t(int, NVME_CAP_MQES(ndev->cap) + 1, NVME_Q_DEPTH);
        ndev->db_stride = 1 << NVME_CAP_STRIDE(ndev->cap);
        ndev->dbs = ((void __iomem *)ndev->bar) + 4096;

        ret = nvme_configure_admin_queue(ndev);
        if (ret)
                goto free_queue;

        /* Allocate after the page size is known */
        ndev->prp_pool = memalign(ndev->page_size, MAX_PRP_POOL);
        if (!ndev->prp_pool) {
                ret = -ENOMEM;
                printf("Error: %s: Out of memory!\n", udev->name);
                goto free_nvme;
        }
        ndev->prp_entry_num = MAX_PRP_POOL >> 3;

        ret = nvme_setup_io_queues(ndev);
        if (ret)
                goto free_queue;

        nvme_get_info_from_identify(ndev);

        return 0;

free_queue:
        free((void *)ndev->queues);
free_nvme:
        return ret;
}

U_BOOT_DRIVER(nvme) = {
        .name   = "nvme",
        .id     = UCLASS_NVME,
        .bind   = nvme_bind,
        .probe  = nvme_probe,
        .priv_auto_alloc_size = sizeof(struct nvme_dev),
};

struct pci_device_id nvme_supported[] = {
        { PCI_DEVICE_CLASS(PCI_CLASS_STORAGE_EXPRESS, ~0) },
        {}
};

U_BOOT_PCI_DEVICE(nvme, nvme_supported);