// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)

#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/log2.h>
#include <linux/mm.h>
#include <linux/netdevice.h>
#include <linux/pci.h>
#include <linux/slab.h>

#include "fun_dev.h"
#include "fun_queue.h"

/* Allocate memory for a queue. This includes the memory for the HW descriptor
 * ring, an optional 64b HW write-back area, and an optional SW state ring.
 * Returns the virtual and DMA addresses of the HW ring, the VA of the SW ring,
 * and the VA of the write-back area.
 */
void *fun_alloc_ring_mem(struct device *dma_dev, size_t depth,
                         size_t hw_desc_sz, size_t sw_desc_sz, bool wb,
                         int numa_node, dma_addr_t *dma_addr, void **sw_va,
                         volatile __be64 **wb_va)
{
        int dev_node = dev_to_node(dma_dev);
        size_t dma_sz;
        void *va;

        if (numa_node == NUMA_NO_NODE)
                numa_node = dev_node;

        /* Place optional write-back area at end of descriptor ring. */
        dma_sz = hw_desc_sz * depth;
        if (wb)
                dma_sz += sizeof(u64);

        set_dev_node(dma_dev, numa_node);
        va = dma_alloc_coherent(dma_dev, dma_sz, dma_addr, GFP_KERNEL);
        set_dev_node(dma_dev, dev_node);
        if (!va)
                return NULL;

        if (sw_desc_sz) {
                *sw_va = kvzalloc_node(sw_desc_sz * depth, GFP_KERNEL,
                                       numa_node);
                if (!*sw_va) {
                        dma_free_coherent(dma_dev, dma_sz, va, *dma_addr);
                        return NULL;
                }
        }

        if (wb)
                *wb_va = va + dma_sz - sizeof(u64);
        return va;
}
EXPORT_SYMBOL_GPL(fun_alloc_ring_mem);

void fun_free_ring_mem(struct device *dma_dev, size_t depth, size_t hw_desc_sz,
                       bool wb, void *hw_va, dma_addr_t dma_addr, void *sw_va)
{
        if (hw_va) {
                size_t sz = depth * hw_desc_sz;

                if (wb)
                        sz += sizeof(u64);
                dma_free_coherent(dma_dev, sz, hw_va, dma_addr);
        }
        kvfree(sw_va);
}
EXPORT_SYMBOL_GPL(fun_free_ring_mem);

/* Prepare and issue an admin command to create an SQ on the device with the
 * provided parameters. If the queue ID is auto-allocated by the device it is
 * returned in *sqidp.
 */
int fun_sq_create(struct fun_dev *fdev, u16 flags, u32 sqid, u32 cqid,
                  u8 sqe_size_log2, u32 sq_depth, dma_addr_t dma_addr,
                  u8 coal_nentries, u8 coal_usec, u32 irq_num,
                  u32 scan_start_id, u32 scan_end_id,
                  u32 rq_buf_size_log2, u32 *sqidp, u32 __iomem **dbp)
{
        union {
                struct fun_admin_epsq_req req;
                struct fun_admin_generic_create_rsp rsp;
        } cmd;
        dma_addr_t wb_addr;
        u32 hw_qid;
        int rc;

        if (sq_depth > fdev->q_depth)
                return -EINVAL;
        if (flags & FUN_ADMIN_EPSQ_CREATE_FLAG_RQ)
                sqe_size_log2 = ilog2(sizeof(struct fun_eprq_rqbuf));

        wb_addr = dma_addr + (sq_depth << sqe_size_log2);

        cmd.req.common = FUN_ADMIN_REQ_COMMON_INIT2(FUN_ADMIN_OP_EPSQ,
                                                    sizeof(cmd.req));
        cmd.req.u.create =
                FUN_ADMIN_EPSQ_CREATE_REQ_INIT(FUN_ADMIN_SUBOP_CREATE, flags,
                                               sqid, cqid, sqe_size_log2,
                                               sq_depth - 1, dma_addr, 0,
                                               coal_nentries, coal_usec,
                                               irq_num, scan_start_id,
                                               scan_end_id, 0,
                                               rq_buf_size_log2,
                                               ilog2(sizeof(u64)), wb_addr);

        rc = fun_submit_admin_sync_cmd(fdev, &cmd.req.common,
                                       &cmd.rsp, sizeof(cmd.rsp), 0);
        if (rc)
                return rc;

        hw_qid = be32_to_cpu(cmd.rsp.id);
        *dbp = fun_sq_db_addr(fdev, hw_qid);
        if (flags & FUN_ADMIN_RES_CREATE_FLAG_ALLOCATOR)
                *sqidp = hw_qid;
        return rc;
}
EXPORT_SYMBOL_GPL(fun_sq_create);

/* Prepare and issue an admin command to create a CQ on the device with the
 * provided parameters. If the queue ID is auto-allocated by the device it is
 * returned in *cqidp.
 */
int fun_cq_create(struct fun_dev *fdev, u16 flags, u32 cqid, u32 rqid,
                  u8 cqe_size_log2, u32 cq_depth, dma_addr_t dma_addr,
                  u16 headroom, u16 tailroom, u8 coal_nentries, u8 coal_usec,
                  u32 irq_num, u32 scan_start_id, u32 scan_end_id, u32 *cqidp,
                  u32 __iomem **dbp)
{
        union {
                struct fun_admin_epcq_req req;
                struct fun_admin_generic_create_rsp rsp;
        } cmd;
        u32 hw_qid;
        int rc;

        if (cq_depth > fdev->q_depth)
                return -EINVAL;

        cmd.req.common = FUN_ADMIN_REQ_COMMON_INIT2(FUN_ADMIN_OP_EPCQ,
                                                    sizeof(cmd.req));
        cmd.req.u.create =
                FUN_ADMIN_EPCQ_CREATE_REQ_INIT(FUN_ADMIN_SUBOP_CREATE, flags,
                                               cqid, rqid, cqe_size_log2,
                                               cq_depth - 1, dma_addr, tailroom,
                                               headroom / 2, 0, coal_nentries,
                                               coal_usec, irq_num,
                                               scan_start_id, scan_end_id, 0);

        rc = fun_submit_admin_sync_cmd(fdev, &cmd.req.common,
                                       &cmd.rsp, sizeof(cmd.rsp), 0);
        if (rc)
                return rc;

        hw_qid = be32_to_cpu(cmd.rsp.id);
        *dbp = fun_cq_db_addr(fdev, hw_qid);
        if (flags & FUN_ADMIN_RES_CREATE_FLAG_ALLOCATOR)
                *cqidp = hw_qid;
        return rc;
}
EXPORT_SYMBOL_GPL(fun_cq_create);

static bool fun_sq_is_head_wb(const struct fun_queue *funq)
{
        return funq->sq_flags & FUN_ADMIN_EPSQ_CREATE_FLAG_HEAD_WB_ADDRESS;
}

static void fun_clean_rq(struct fun_queue *funq)
{
        struct fun_dev *fdev = funq->fdev;
        struct fun_rq_info *rqinfo;
        unsigned int i;

        for (i = 0; i < funq->rq_depth; i++) {
                rqinfo = &funq->rq_info[i];
                if (rqinfo->page) {
                        dma_unmap_page(fdev->dev, rqinfo->dma, PAGE_SIZE,
                                       DMA_FROM_DEVICE);
                        put_page(rqinfo->page);
                        rqinfo->page = NULL;
                }
        }
}

static int fun_fill_rq(struct fun_queue *funq)
{
        struct device *dev = funq->fdev->dev;
        int i, node = dev_to_node(dev);
        struct fun_rq_info *rqinfo;

        for (i = 0; i < funq->rq_depth; i++) {
                rqinfo = &funq->rq_info[i];
                rqinfo->page = alloc_pages_node(node, GFP_KERNEL, 0);
                if (unlikely(!rqinfo->page))
                        return -ENOMEM;

                rqinfo->dma = dma_map_page(dev, rqinfo->page, 0,
                                           PAGE_SIZE, DMA_FROM_DEVICE);
                if (unlikely(dma_mapping_error(dev, rqinfo->dma))) {
                        put_page(rqinfo->page);
                        rqinfo->page = NULL;
                        return -ENOMEM;
                }

                funq->rqes[i] = FUN_EPRQ_RQBUF_INIT(rqinfo->dma);
        }

        funq->rq_tail = funq->rq_depth - 1;
        return 0;
}

static void fun_rq_update_pos(struct fun_queue *funq, int buf_offset)
{
        if (buf_offset <= funq->rq_buf_offset) {
                struct fun_rq_info *rqinfo = &funq->rq_info[funq->rq_buf_idx];
                struct device *dev = funq->fdev->dev;

                dma_sync_single_for_device(dev, rqinfo->dma, PAGE_SIZE,
                                           DMA_FROM_DEVICE);
                funq->num_rqe_to_fill++;
                if (++funq->rq_buf_idx == funq->rq_depth)
                        funq->rq_buf_idx = 0;
        }
        funq->rq_buf_offset = buf_offset;
}

/* Given a command response with data scattered across >= 1 RQ buffers return
 * a pointer to a contiguous buffer containing all the data. If the data is in
 * one RQ buffer the start address within that buffer is returned, otherwise a
 * new buffer is allocated and the data is gathered into it.
 */
static void *fun_data_from_rq(struct fun_queue *funq,
                              const struct fun_rsp_common *rsp, bool *need_free)
{
        u32 bufoff, total_len, remaining, fragsize, dataoff;
        struct device *dma_dev = funq->fdev->dev;
        const struct fun_dataop_rqbuf *databuf;
        const struct fun_dataop_hdr *dataop;
        const struct fun_rq_info *rqinfo;
        void *data;

        dataop = (void *)rsp + rsp->suboff8 * 8;
        total_len = be32_to_cpu(dataop->total_len);

        if (likely(dataop->nsgl == 1)) {
                databuf = (struct fun_dataop_rqbuf *)dataop->imm;
                bufoff = be32_to_cpu(databuf->bufoff);
                fun_rq_update_pos(funq, bufoff);
                rqinfo = &funq->rq_info[funq->rq_buf_idx];
                dma_sync_single_for_cpu(dma_dev, rqinfo->dma + bufoff,
                                        total_len, DMA_FROM_DEVICE);
                *need_free = false;
                return page_address(rqinfo->page) + bufoff;
        }

        /* For scattered completions gather the fragments into one buffer. */

        data = kmalloc(total_len, GFP_ATOMIC);
        /* NULL is OK here. In case of failure we still need to consume the data
         * for proper buffer accounting but indicate an error in the response.
         */
        if (likely(data))
                *need_free = true;

        dataoff = 0;
        for (remaining = total_len; remaining; remaining -= fragsize) {
                fun_rq_update_pos(funq, 0);
                fragsize = min_t(unsigned int, PAGE_SIZE, remaining);
                if (data) {
                        rqinfo = &funq->rq_info[funq->rq_buf_idx];
                        dma_sync_single_for_cpu(dma_dev, rqinfo->dma, fragsize,
                                                DMA_FROM_DEVICE);
                        memcpy(data + dataoff, page_address(rqinfo->page),
                               fragsize);
                        dataoff += fragsize;
                }
        }
        return data;
}

unsigned int __fun_process_cq(struct fun_queue *funq, unsigned int max)
{
        const struct fun_cqe_info *info;
        struct fun_rsp_common *rsp;
        unsigned int new_cqes;
        u16 sf_p, flags;
        bool need_free;
        void *cqe;

        if (!max)
                max = funq->cq_depth - 1;

        for (new_cqes = 0; new_cqes < max; new_cqes++) {
                cqe = funq->cqes + (funq->cq_head << funq->cqe_size_log2);
                info = funq_cqe_info(funq, cqe);
                sf_p = be16_to_cpu(info->sf_p);

                if ((sf_p & 1) != funq->cq_phase)
                        break;

                /* ensure the phase tag is read before other CQE fields */
                dma_rmb();

                if (++funq->cq_head == funq->cq_depth) {
                        funq->cq_head = 0;
                        funq->cq_phase = !funq->cq_phase;
                }

                rsp = cqe;
                flags = be16_to_cpu(rsp->flags);

                need_free = false;
                if (unlikely(flags & FUN_REQ_COMMON_FLAG_CQE_IN_RQBUF)) {
                        rsp = fun_data_from_rq(funq, rsp, &need_free);
                        if (!rsp) {
                                rsp = cqe;
                                rsp->len8 = 1;
                                if (rsp->ret == 0)
                                        rsp->ret = ENOMEM;
                        }
                }

                if (funq->cq_cb)
                        funq->cq_cb(funq, funq->cb_data, rsp, info);
                if (need_free)
                        kfree(rsp);
        }

        dev_dbg(funq->fdev->dev, "CQ %u, new CQEs %u/%u, head %u, phase %u\n",
                funq->cqid, new_cqes, max, funq->cq_head, funq->cq_phase);
        return new_cqes;
}

unsigned int fun_process_cq(struct fun_queue *funq, unsigned int max)
{
        unsigned int processed;
        u32 db;

        processed = __fun_process_cq(funq, max);

        if (funq->num_rqe_to_fill) {
                funq->rq_tail = (funq->rq_tail + funq->num_rqe_to_fill) %
                                funq->rq_depth;
                funq->num_rqe_to_fill = 0;
                writel(funq->rq_tail, funq->rq_db);
        }

        db = funq->cq_head | FUN_DB_IRQ_ARM_F;
        writel(db, funq->cq_db);
        return processed;
}

static int fun_alloc_sqes(struct fun_queue *funq)
{
        funq->sq_cmds = fun_alloc_ring_mem(funq->fdev->dev, funq->sq_depth,
                                           1 << funq->sqe_size_log2, 0,
                                           fun_sq_is_head_wb(funq),
                                           NUMA_NO_NODE, &funq->sq_dma_addr,
                                           NULL, &funq->sq_head);
        return funq->sq_cmds ? 0 : -ENOMEM;
}

static int fun_alloc_cqes(struct fun_queue *funq)
{
        funq->cqes = fun_alloc_ring_mem(funq->fdev->dev, funq->cq_depth,
                                        1 << funq->cqe_size_log2, 0, false,
                                        NUMA_NO_NODE, &funq->cq_dma_addr, NULL,
                                        NULL);
        return funq->cqes ? 0 : -ENOMEM;
}

static int fun_alloc_rqes(struct fun_queue *funq)
{
        funq->rqes = fun_alloc_ring_mem(funq->fdev->dev, funq->rq_depth,
                                        sizeof(*funq->rqes),
                                        sizeof(*funq->rq_info), false,
                                        NUMA_NO_NODE, &funq->rq_dma_addr,
                                        (void **)&funq->rq_info, NULL);
        return funq->rqes ? 0 : -ENOMEM;
}

/* Free a queue's structures. */
void fun_free_queue(struct fun_queue *funq)
{
        struct device *dev = funq->fdev->dev;

        fun_free_ring_mem(dev, funq->cq_depth, 1 << funq->cqe_size_log2, false,
                          funq->cqes, funq->cq_dma_addr, NULL);
        fun_free_ring_mem(dev, funq->sq_depth, 1 << funq->sqe_size_log2,
                          fun_sq_is_head_wb(funq), funq->sq_cmds,
                          funq->sq_dma_addr, NULL);

        if (funq->rqes) {
                fun_clean_rq(funq);
                fun_free_ring_mem(dev, funq->rq_depth, sizeof(*funq->rqes),
                                  false, funq->rqes, funq->rq_dma_addr,
                                  funq->rq_info);
        }

        kfree(funq);
}

/* Allocate and initialize a funq's structures. */
struct fun_queue *fun_alloc_queue(struct fun_dev *fdev, int qid,
                                  const struct fun_queue_alloc_req *req)
{
        struct fun_queue *funq = kzalloc_obj(*funq);

        if (!funq)
                return NULL;

        funq->fdev = fdev;
        spin_lock_init(&funq->sq_lock);

        funq->qid = qid;

        /* Initial CQ/SQ/RQ ids */
        if (req->rq_depth) {
                funq->cqid = 2 * qid;
                if (funq->qid) {
                        /* I/O Q: use rqid = cqid, sqid = +1 */
                        funq->rqid = funq->cqid;
                        funq->sqid = funq->rqid + 1;
                } else {
                        /* Admin Q: sqid is always 0, use ID 1 for RQ */
                        funq->sqid = 0;
                        funq->rqid = 1;
                }
        } else {
                funq->cqid = qid;
                funq->sqid = qid;
        }

        funq->cq_flags = req->cq_flags;
        funq->sq_flags = req->sq_flags;

        funq->cqe_size_log2 = req->cqe_size_log2;
        funq->sqe_size_log2 = req->sqe_size_log2;

        funq->cq_depth = req->cq_depth;
        funq->sq_depth = req->sq_depth;

        funq->cq_intcoal_nentries = req->cq_intcoal_nentries;
        funq->cq_intcoal_usec = req->cq_intcoal_usec;

        funq->sq_intcoal_nentries = req->sq_intcoal_nentries;
        funq->sq_intcoal_usec = req->sq_intcoal_usec;

        if (fun_alloc_cqes(funq))
                goto free_funq;

        funq->cq_phase = 1;

        if (fun_alloc_sqes(funq))
                goto free_funq;

        if (req->rq_depth) {
                funq->rq_flags = req->rq_flags | FUN_ADMIN_EPSQ_CREATE_FLAG_RQ;
                funq->rq_depth = req->rq_depth;
                funq->rq_buf_offset = -1;

                if (fun_alloc_rqes(funq) || fun_fill_rq(funq))
                        goto free_funq;
        }

        funq->cq_vector = -1;
        funq->cqe_info_offset = (1 << funq->cqe_size_log2) - sizeof(struct fun_cqe_info);

        /* SQ/CQ 0 are implicitly created, assign their doorbells now.
         * Other queues are assigned doorbells at their explicit creation.
         */
        if (funq->sqid == 0)
                funq->sq_db = fun_sq_db_addr(fdev, 0);
        if (funq->cqid == 0)
                funq->cq_db = fun_cq_db_addr(fdev, 0);

        return funq;

free_funq:
        fun_free_queue(funq);
        return NULL;
}

/* Create a funq's RQ on the device. */
int fun_create_rq(struct fun_queue *funq)
{
        struct fun_dev *fdev = funq->fdev;
        int rc;

        rc = fun_sq_create(fdev, funq->rq_flags, funq->rqid, funq->cqid, 0,
                           funq->rq_depth, funq->rq_dma_addr, 0, 0,
                           funq->cq_vector, 0, 0, PAGE_SHIFT, &funq->rqid,
                           &funq->rq_db);
        if (!rc)
                dev_dbg(fdev->dev, "created RQ %u\n", funq->rqid);

        return rc;
}

static unsigned int funq_irq(struct fun_queue *funq)
{
        return pci_irq_vector(to_pci_dev(funq->fdev->dev), funq->cq_vector);
}

int fun_request_irq(struct fun_queue *funq, const char *devname,
                    irq_handler_t handler, void *data)
{
        int rc;

        if (funq->cq_vector < 0)
                return -EINVAL;

        funq->irq_handler = handler;
        funq->irq_data = data;

        snprintf(funq->irqname, sizeof(funq->irqname),
                 funq->qid ? "%s-q[%d]" : "%s-adminq", devname, funq->qid);

        rc = request_irq(funq_irq(funq), handler, 0, funq->irqname, data);
        if (rc)
                funq->irq_handler = NULL;

        return rc;
}

void fun_free_irq(struct fun_queue *funq)
{
        if (funq->irq_handler) {
                unsigned int vector = funq_irq(funq);

                free_irq(vector, funq->irq_data);
                funq->irq_handler = NULL;
                funq->irq_data = NULL;
        }
}