/*
 * Copyright 2014 Cisco Systems, Inc.  All rights reserved.
 *
 * This program is free software; you may redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/if_ether.h>
#include <linux/slab.h>
#include "vnic_resource.h"
#include "vnic_devcmd.h"
#include "vnic_dev.h"
#include "vnic_stats.h"
#include "vnic_wq.h"

#define VNIC_DVCMD_TMO  10000   /* Devcmd Timeout value */
#define VNIC_NOTIFY_INTR_MASK 0x0000ffff00000000ULL

struct devcmd2_controller {
        struct vnic_wq_ctrl __iomem *wq_ctrl;
        struct vnic_dev_ring results_ring;
        struct vnic_wq wq;
        struct vnic_devcmd2 *cmd_ring;
        struct devcmd2_result *result;
        u16 next_result;
        u16 result_size;
        int color;
};

struct vnic_res {
        void __iomem *vaddr;
        unsigned int count;
};

struct vnic_dev {
        void *priv;
        struct pci_dev *pdev;
        struct vnic_res res[RES_TYPE_MAX];
        enum vnic_dev_intr_mode intr_mode;
        struct vnic_devcmd __iomem *devcmd;
        struct vnic_devcmd_notify *notify;
        struct vnic_devcmd_notify notify_copy;
        dma_addr_t notify_pa;
        u32 *linkstatus;
        dma_addr_t linkstatus_pa;
        struct vnic_stats *stats;
        dma_addr_t stats_pa;
        struct vnic_devcmd_fw_info *fw_info;
        dma_addr_t fw_info_pa;
        u64 args[VNIC_DEVCMD_NARGS];
        struct devcmd2_controller *devcmd2;

        int (*devcmd_rtn)(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd,
                          int wait);
};

#define VNIC_MAX_RES_HDR_SIZE \
        (sizeof(struct vnic_resource_header) + \
        sizeof(struct vnic_resource) * RES_TYPE_MAX)
#define VNIC_RES_STRIDE 128

void *svnic_dev_priv(struct vnic_dev *vdev)
{
        return vdev->priv;
}

static int vnic_dev_discover_res(struct vnic_dev *vdev,
        struct vnic_dev_bar *bar, unsigned int num_bars)
{
        struct vnic_resource_header __iomem *rh;
        struct vnic_resource __iomem *r;
        u8 type;

        if (num_bars == 0)
                return -EINVAL;

        if (bar->len < VNIC_MAX_RES_HDR_SIZE) {
                pr_err("vNIC BAR0 res hdr length error\n");

                return -EINVAL;
        }

        rh = bar->vaddr;
        if (!rh) {
                pr_err("vNIC BAR0 res hdr not mem-mapped\n");

                return -EINVAL;
        }

        if (ioread32(&rh->magic) != VNIC_RES_MAGIC ||
            ioread32(&rh->version) != VNIC_RES_VERSION) {
                pr_err("vNIC BAR0 res magic/version error exp (%lx/%lx) curr (%x/%x)\n",
                        VNIC_RES_MAGIC, VNIC_RES_VERSION,
                        ioread32(&rh->magic), ioread32(&rh->version));

                return -EINVAL;
        }

        r = (struct vnic_resource __iomem *)(rh + 1);

        while ((type = ioread8(&r->type)) != RES_TYPE_EOL) {

                u8 bar_num = ioread8(&r->bar);
                u32 bar_offset = ioread32(&r->bar_offset);
                u32 count = ioread32(&r->count);
                u32 len;

                r++;

                if (bar_num >= num_bars)
                        continue;

                if (!bar[bar_num].len || !bar[bar_num].vaddr)
                        continue;

                switch (type) {
                case RES_TYPE_WQ:
                case RES_TYPE_RQ:
                case RES_TYPE_CQ:
                case RES_TYPE_INTR_CTRL:
                        /* each count is stride bytes long */
                        len = count * VNIC_RES_STRIDE;
                        if (len + bar_offset > bar->len) {
                                pr_err("vNIC BAR0 resource %d out-of-bounds, offset 0x%x + size 0x%x > bar len 0x%lx\n",
                                        type, bar_offset,
                                        len,
                                        bar->len);

                                return -EINVAL;
                        }
                        break;

                case RES_TYPE_INTR_PBA_LEGACY:
                case RES_TYPE_DEVCMD:
                case RES_TYPE_DEVCMD2:
                        len = count;
                        break;

                default:
                        continue;
                }

                vdev->res[type].count = count;
                vdev->res[type].vaddr = (char __iomem *)bar->vaddr + bar_offset;
        }

        return 0;
}

unsigned int svnic_dev_get_res_count(struct vnic_dev *vdev,
        enum vnic_res_type type)
{
        return vdev->res[type].count;
}

void __iomem *svnic_dev_get_res(struct vnic_dev *vdev, enum vnic_res_type type,
        unsigned int index)
{
        if (!vdev->res[type].vaddr)
                return NULL;

        switch (type) {
        case RES_TYPE_WQ:
        case RES_TYPE_RQ:
        case RES_TYPE_CQ:
        case RES_TYPE_INTR_CTRL:
                return (char __iomem *)vdev->res[type].vaddr +
                                        index * VNIC_RES_STRIDE;

        default:
                return (char __iomem *)vdev->res[type].vaddr;
        }
}

unsigned int svnic_dev_desc_ring_size(struct vnic_dev_ring *ring,
                                      unsigned int desc_count,
                                      unsigned int desc_size)
{
        /* The base address of the desc rings must be 512 byte aligned.
         * Descriptor count is aligned to groups of 32 descriptors.  A
         * count of 0 means the maximum 4096 descriptors.  Descriptor
         * size is aligned to 16 bytes.
         */

        unsigned int count_align = 32;
        unsigned int desc_align = 16;

        ring->base_align = 512;

        if (desc_count == 0)
                desc_count = 4096;

        ring->desc_count = ALIGN(desc_count, count_align);

        ring->desc_size = ALIGN(desc_size, desc_align);

        ring->size = ring->desc_count * ring->desc_size;
        ring->size_unaligned = ring->size + ring->base_align;

        return ring->size_unaligned;
}

void svnic_dev_clear_desc_ring(struct vnic_dev_ring *ring)
{
        memset(ring->descs, 0, ring->size);
}

int svnic_dev_alloc_desc_ring(struct vnic_dev *vdev, struct vnic_dev_ring *ring,
        unsigned int desc_count, unsigned int desc_size)
{
        svnic_dev_desc_ring_size(ring, desc_count, desc_size);

        ring->descs_unaligned = dma_alloc_coherent(&vdev->pdev->dev,
                        ring->size_unaligned, &ring->base_addr_unaligned,
                        GFP_KERNEL);
        if (!ring->descs_unaligned) {
                pr_err("Failed to allocate ring (size=%d), aborting\n",
                        (int)ring->size);

                return -ENOMEM;
        }

        ring->base_addr = ALIGN(ring->base_addr_unaligned,
                ring->base_align);
        ring->descs = (u8 *)ring->descs_unaligned +
                (ring->base_addr - ring->base_addr_unaligned);

        svnic_dev_clear_desc_ring(ring);

        ring->desc_avail = ring->desc_count - 1;

        return 0;
}

void svnic_dev_free_desc_ring(struct vnic_dev *vdev, struct vnic_dev_ring *ring)
{
        if (ring->descs) {
                dma_free_coherent(&vdev->pdev->dev,
                        ring->size_unaligned,
                        ring->descs_unaligned,
                        ring->base_addr_unaligned);
                ring->descs = NULL;
        }
}

static int _svnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd,
        int wait)
{
        struct devcmd2_controller *dc2c = vdev->devcmd2;
        struct devcmd2_result *result = NULL;
        unsigned int i;
        int delay;
        int err;
        u32 posted;
        u32 fetch_idx;
        u32 new_posted;
        u8 color;

        fetch_idx = ioread32(&dc2c->wq_ctrl->fetch_index);
        if (fetch_idx == 0xFFFFFFFF) { /* check for hardware gone  */
                /* Hardware surprise removal: return error */
                return -ENODEV;
        }

        posted = ioread32(&dc2c->wq_ctrl->posted_index);

        if (posted == 0xFFFFFFFF) { /* check for hardware gone  */
                /* Hardware surprise removal: return error */
                return -ENODEV;
        }

        new_posted = (posted + 1) % DEVCMD2_RING_SIZE;
        if (new_posted == fetch_idx) {
                pr_err("%s: wq is full while issuing devcmd2 command %d, fetch index: %u, posted index: %u\n",
                        pci_name(vdev->pdev), _CMD_N(cmd), fetch_idx, posted);

                return -EBUSY;
        }

        dc2c->cmd_ring[posted].cmd = cmd;
        dc2c->cmd_ring[posted].flags = 0;

        if ((_CMD_FLAGS(cmd) & _CMD_FLAGS_NOWAIT))
                dc2c->cmd_ring[posted].flags |= DEVCMD2_FNORESULT;

        if (_CMD_DIR(cmd) & _CMD_DIR_WRITE) {
                for (i = 0; i < VNIC_DEVCMD_NARGS; i++)
                        dc2c->cmd_ring[posted].args[i] = vdev->args[i];
        }
        /* Adding write memory barrier prevents compiler and/or CPU
         * reordering, thus avoiding descriptor posting before
         * descriptor is initialized. Otherwise, hardware can read
         * stale descriptor fields.
         */
        wmb();
        iowrite32(new_posted, &dc2c->wq_ctrl->posted_index);

        if (dc2c->cmd_ring[posted].flags & DEVCMD2_FNORESULT)
                return 0;

        result = dc2c->result + dc2c->next_result;
        color = dc2c->color;

        /*
         * Increment next_result, after posting the devcmd, irrespective of
         * devcmd result, and it should be done only once.
         */
        dc2c->next_result++;
        if (dc2c->next_result == dc2c->result_size) {
                dc2c->next_result = 0;
                dc2c->color = dc2c->color ? 0 : 1;
        }

        for (delay = 0; delay < wait; delay++) {
                udelay(100);
                if (result->color == color) {
                        if (result->error) {
                                err = (int) result->error;
                                if (err != ERR_ECMDUNKNOWN ||
                                    cmd != CMD_CAPABILITY)
                                        pr_err("Error %d devcmd %d\n",
                                                err, _CMD_N(cmd));

                                return err;
                        }
                        if (_CMD_DIR(cmd) & _CMD_DIR_READ) {
                                for (i = 0; i < VNIC_DEVCMD_NARGS; i++)
                                        vdev->args[i] = result->results[i];
                        }

                        return 0;
                }
        }

        pr_err("Timed out devcmd %d\n", _CMD_N(cmd));

        return -ETIMEDOUT;
}

static int svnic_dev_init_devcmd2(struct vnic_dev *vdev)
{
        struct devcmd2_controller *dc2c = NULL;
        unsigned int fetch_idx;
        int ret;
        void __iomem *p;

        if (vdev->devcmd2)
                return 0;

        p = svnic_dev_get_res(vdev, RES_TYPE_DEVCMD2, 0);
        if (!p)
                return -ENODEV;

        dc2c = kzalloc(sizeof(*dc2c), GFP_ATOMIC);
        if (!dc2c)
                return -ENOMEM;

        vdev->devcmd2 = dc2c;

        dc2c->color = 1;
        dc2c->result_size = DEVCMD2_RING_SIZE;

        ret  = vnic_wq_devcmd2_alloc(vdev,
                                     &dc2c->wq,
                                     DEVCMD2_RING_SIZE,
                                     DEVCMD2_DESC_SIZE);
        if (ret)
                goto err_free_devcmd2;

        fetch_idx = ioread32(&dc2c->wq.ctrl->fetch_index);
        if (fetch_idx == 0xFFFFFFFF) { /* check for hardware gone  */
                /* Hardware surprise removal: reset fetch_index */
                fetch_idx = 0;
        }

        /*
         * Don't change fetch_index ever and
         * set posted_index same as fetch_index
         * when setting up the WQ for devcmd2.
         */
        vnic_wq_init_start(&dc2c->wq, 0, fetch_idx, fetch_idx, 0, 0);
        svnic_wq_enable(&dc2c->wq);
        ret = svnic_dev_alloc_desc_ring(vdev,
                                        &dc2c->results_ring,
                                        DEVCMD2_RING_SIZE,
                                        DEVCMD2_DESC_SIZE);
        if (ret)
                goto err_free_wq;

        dc2c->result = (struct devcmd2_result *) dc2c->results_ring.descs;
        dc2c->cmd_ring = (struct vnic_devcmd2 *) dc2c->wq.ring.descs;
        dc2c->wq_ctrl = dc2c->wq.ctrl;
        vdev->args[0] = (u64) dc2c->results_ring.base_addr | VNIC_PADDR_TARGET;
        vdev->args[1] = DEVCMD2_RING_SIZE;

        ret = _svnic_dev_cmd2(vdev, CMD_INITIALIZE_DEVCMD2, VNIC_DVCMD_TMO);
        if (ret < 0)
                goto err_free_desc_ring;

        vdev->devcmd_rtn = &_svnic_dev_cmd2;
        pr_info("DEVCMD2 Initialized.\n");

        return ret;

err_free_desc_ring:
        svnic_dev_free_desc_ring(vdev, &dc2c->results_ring);

err_free_wq:
        svnic_wq_disable(&dc2c->wq);
        svnic_wq_free(&dc2c->wq);

err_free_devcmd2:
        kfree(dc2c);
        vdev->devcmd2 = NULL;

        return ret;
} /* end of svnic_dev_init_devcmd2 */

static void vnic_dev_deinit_devcmd2(struct vnic_dev *vdev)
{
        struct devcmd2_controller *dc2c = vdev->devcmd2;

        vdev->devcmd2 = NULL;
        vdev->devcmd_rtn = NULL;

        svnic_dev_free_desc_ring(vdev, &dc2c->results_ring);
        svnic_wq_disable(&dc2c->wq);
        svnic_wq_free(&dc2c->wq);
        kfree(dc2c);
}

int svnic_dev_cmd(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd,
        u64 *a0, u64 *a1, int wait)
{
        int err;

        memset(vdev->args, 0, sizeof(vdev->args));
        vdev->args[0] = *a0;
        vdev->args[1] = *a1;

        err = (*vdev->devcmd_rtn)(vdev, cmd, wait);

        *a0 = vdev->args[0];
        *a1 = vdev->args[1];

        return  err;
}

int svnic_dev_fw_info(struct vnic_dev *vdev,
        struct vnic_devcmd_fw_info **fw_info)
{
        u64 a0, a1 = 0;
        int wait = VNIC_DVCMD_TMO;
        int err = 0;

        if (!vdev->fw_info) {
                vdev->fw_info = dma_alloc_coherent(&vdev->pdev->dev,
                        sizeof(struct vnic_devcmd_fw_info),
                        &vdev->fw_info_pa, GFP_KERNEL);
                if (!vdev->fw_info)
                        return -ENOMEM;

                a0 = vdev->fw_info_pa;

                /* only get fw_info once and cache it */
                err = svnic_dev_cmd(vdev, CMD_MCPU_FW_INFO, &a0, &a1, wait);
        }

        *fw_info = vdev->fw_info;

        return err;
}

int svnic_dev_spec(struct vnic_dev *vdev, unsigned int offset,
        unsigned int size, void *value)
{
        u64 a0, a1;
        int wait = VNIC_DVCMD_TMO;
        int err;

        a0 = offset;
        a1 = size;

        err = svnic_dev_cmd(vdev, CMD_DEV_SPEC, &a0, &a1, wait);

        switch (size) {
        case 1:
                *(u8 *)value = (u8)a0;
                break;
        case 2:
                *(u16 *)value = (u16)a0;
                break;
        case 4:
                *(u32 *)value = (u32)a0;
                break;
        case 8:
                *(u64 *)value = a0;
                break;
        default:
                BUG();
                break;
        }

        return err;
}

int svnic_dev_stats_clear(struct vnic_dev *vdev)
{
        u64 a0 = 0, a1 = 0;
        int wait = VNIC_DVCMD_TMO;

        return svnic_dev_cmd(vdev, CMD_STATS_CLEAR, &a0, &a1, wait);
}

int svnic_dev_stats_dump(struct vnic_dev *vdev, struct vnic_stats **stats)
{
        u64 a0, a1;
        int wait = VNIC_DVCMD_TMO;

        if (!vdev->stats) {
                vdev->stats = dma_alloc_coherent(&vdev->pdev->dev,
                        sizeof(struct vnic_stats), &vdev->stats_pa, GFP_KERNEL);
                if (!vdev->stats)
                        return -ENOMEM;
        }

        *stats = vdev->stats;
        a0 = vdev->stats_pa;
        a1 = sizeof(struct vnic_stats);

        return svnic_dev_cmd(vdev, CMD_STATS_DUMP, &a0, &a1, wait);
}

int svnic_dev_close(struct vnic_dev *vdev)
{
        u64 a0 = 0, a1 = 0;
        int wait = VNIC_DVCMD_TMO;

        return svnic_dev_cmd(vdev, CMD_CLOSE, &a0, &a1, wait);
}

int svnic_dev_enable_wait(struct vnic_dev *vdev)
{
        u64 a0 = 0, a1 = 0;
        int wait = VNIC_DVCMD_TMO;
        int err = 0;

        err = svnic_dev_cmd(vdev, CMD_ENABLE_WAIT, &a0, &a1, wait);
        if (err == ERR_ECMDUNKNOWN)
                return svnic_dev_cmd(vdev, CMD_ENABLE, &a0, &a1, wait);

        return err;
}

int svnic_dev_disable(struct vnic_dev *vdev)
{
        u64 a0 = 0, a1 = 0;
        int wait = VNIC_DVCMD_TMO;

        return svnic_dev_cmd(vdev, CMD_DISABLE, &a0, &a1, wait);
}

int svnic_dev_open(struct vnic_dev *vdev, int arg)
{
        u64 a0 = (u32)arg, a1 = 0;
        int wait = VNIC_DVCMD_TMO;

        return svnic_dev_cmd(vdev, CMD_OPEN, &a0, &a1, wait);
}

int svnic_dev_open_done(struct vnic_dev *vdev, int *done)
{
        u64 a0 = 0, a1 = 0;
        int wait = VNIC_DVCMD_TMO;
        int err;

        *done = 0;

        err = svnic_dev_cmd(vdev, CMD_OPEN_STATUS, &a0, &a1, wait);
        if (err)
                return err;

        *done = (a0 == 0);

        return 0;
}

int svnic_dev_notify_set(struct vnic_dev *vdev, u16 intr)
{
        u64 a0, a1;
        int wait = VNIC_DVCMD_TMO;

        if (!vdev->notify) {
                vdev->notify = dma_alloc_coherent(&vdev->pdev->dev,
                        sizeof(struct vnic_devcmd_notify),
                        &vdev->notify_pa, GFP_KERNEL);
                if (!vdev->notify)
                        return -ENOMEM;
        }

        a0 = vdev->notify_pa;
        a1 = ((u64)intr << 32) & VNIC_NOTIFY_INTR_MASK;
        a1 += sizeof(struct vnic_devcmd_notify);

        return svnic_dev_cmd(vdev, CMD_NOTIFY, &a0, &a1, wait);
}

void svnic_dev_notify_unset(struct vnic_dev *vdev)
{
        u64 a0, a1;
        int wait = VNIC_DVCMD_TMO;

        a0 = 0;  /* paddr = 0 to unset notify buffer */
        a1 = VNIC_NOTIFY_INTR_MASK; /* intr num = -1 to unreg for intr */
        a1 += sizeof(struct vnic_devcmd_notify);

        svnic_dev_cmd(vdev, CMD_NOTIFY, &a0, &a1, wait);
}

static int vnic_dev_notify_ready(struct vnic_dev *vdev)
{
        u32 *words;
        unsigned int nwords = sizeof(struct vnic_devcmd_notify) / 4;
        unsigned int i;
        u32 csum;

        if (!vdev->notify)
                return 0;

        do {
                csum = 0;
                memcpy(&vdev->notify_copy, vdev->notify,
                        sizeof(struct vnic_devcmd_notify));
                words = (u32 *)&vdev->notify_copy;
                for (i = 1; i < nwords; i++)
                        csum += words[i];
        } while (csum != words[0]);

        return 1;
}

int svnic_dev_init(struct vnic_dev *vdev, int arg)
{
        u64 a0 = (u32)arg, a1 = 0;
        int wait = VNIC_DVCMD_TMO;

        return svnic_dev_cmd(vdev, CMD_INIT, &a0, &a1, wait);
}

int svnic_dev_link_status(struct vnic_dev *vdev)
{
        if (vdev->linkstatus)
                return *vdev->linkstatus;

        if (!vnic_dev_notify_ready(vdev))
                return 0;

        return vdev->notify_copy.link_state;
}

u32 svnic_dev_link_down_cnt(struct vnic_dev *vdev)
{
        if (!vnic_dev_notify_ready(vdev))
                return 0;

        return vdev->notify_copy.link_down_cnt;
}

void svnic_dev_set_intr_mode(struct vnic_dev *vdev,
        enum vnic_dev_intr_mode intr_mode)
{
        vdev->intr_mode = intr_mode;
}

enum vnic_dev_intr_mode svnic_dev_get_intr_mode(struct vnic_dev *vdev)
{
        return vdev->intr_mode;
}

void svnic_dev_unregister(struct vnic_dev *vdev)
{
        if (vdev) {
                if (vdev->notify)
                        dma_free_coherent(&vdev->pdev->dev,
                                sizeof(struct vnic_devcmd_notify),
                                vdev->notify,
                                vdev->notify_pa);
                if (vdev->linkstatus)
                        dma_free_coherent(&vdev->pdev->dev,
                                sizeof(u32),
                                vdev->linkstatus,
                                vdev->linkstatus_pa);
                if (vdev->stats)
                        dma_free_coherent(&vdev->pdev->dev,
                                sizeof(struct vnic_stats),
                                vdev->stats, vdev->stats_pa);
                if (vdev->fw_info)
                        dma_free_coherent(&vdev->pdev->dev,
                                sizeof(struct vnic_devcmd_fw_info),
                                vdev->fw_info, vdev->fw_info_pa);
                if (vdev->devcmd2)
                        vnic_dev_deinit_devcmd2(vdev);
                kfree(vdev);
        }
}

struct vnic_dev *svnic_dev_alloc_discover(struct vnic_dev *vdev,
                                          void *priv,
                                          struct pci_dev *pdev,
                                          struct vnic_dev_bar *bar,
                                          unsigned int num_bars)
{
        if (!vdev) {
                vdev = kzalloc(sizeof(struct vnic_dev), GFP_ATOMIC);
                if (!vdev)
                        return NULL;
        }

        vdev->priv = priv;
        vdev->pdev = pdev;

        if (vnic_dev_discover_res(vdev, bar, num_bars))
                goto err_out;

        return vdev;

err_out:
        svnic_dev_unregister(vdev);

        return NULL;
} /* end of svnic_dev_alloc_discover */

/*
 * fallback option is left to keep the interface common for other vnics.
 */
int svnic_dev_cmd_init(struct vnic_dev *vdev, int fallback)
{
        int err = -ENODEV;
        void __iomem *p;

        p = svnic_dev_get_res(vdev, RES_TYPE_DEVCMD2, 0);
        if (p)
                err = svnic_dev_init_devcmd2(vdev);
        else
                pr_err("DEVCMD2 resource not found.\n");

        return err;
} /* end of svnic_dev_cmd_init */