root/drivers/net/wireless/quantenna/qtnfmac/pcie/topaz_pcie.c
// SPDX-License-Identifier: GPL-2.0+
/* Copyright (c) 2018 Quantenna Communications */

#include <linux/kernel.h>
#include <linux/firmware.h>
#include <linux/pci.h>
#include <linux/vmalloc.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/crc32.h>
#include <linux/completion.h>
#include <linux/spinlock.h>
#include <linux/circ_buf.h>

#include "pcie_priv.h"
#include "topaz_pcie_regs.h"
#include "topaz_pcie_ipc.h"
#include "qtn_hw_ids.h"
#include "core.h"
#include "bus.h"
#include "shm_ipc.h"
#include "debug.h"

#define TOPAZ_TX_BD_SIZE_DEFAULT        128
#define TOPAZ_RX_BD_SIZE_DEFAULT        256

struct qtnf_topaz_tx_bd {
        __le32 addr;
        __le32 info;
} __packed;

struct qtnf_topaz_rx_bd {
        __le32 addr;
        __le32 info;
} __packed;

struct qtnf_extra_bd_params {
        __le32 param1;
        __le32 param2;
        __le32 param3;
        __le32 param4;
} __packed;

#define QTNF_BD_PARAM_OFFSET(n) offsetof(struct qtnf_extra_bd_params, param##n)

struct vmac_pkt_info {
        __le32 addr;
        __le32 info;
};

struct qtnf_topaz_bda {
        __le16  bda_len;
        __le16  bda_version;
        __le32  bda_bootstate;
        __le32  bda_dma_mask;
        __le32  bda_dma_offset;
        __le32  bda_flags;
        __le32  bda_img;
        __le32  bda_img_size;
        __le32  bda_ep2h_irqstatus;
        __le32  bda_h2ep_irqstatus;
        __le32  bda_msi_addr;
        u8      reserved1[56];
        __le32  bda_flashsz;
        u8      bda_boardname[PCIE_BDA_NAMELEN];
        __le32  bda_pci_pre_status;
        __le32  bda_pci_endian;
        __le32  bda_pci_post_status;
        __le32  bda_h2ep_txd_budget;
        __le32  bda_ep2h_txd_budget;
        __le32  bda_rc_rx_bd_base;
        __le32  bda_rc_rx_bd_num;
        __le32  bda_rc_tx_bd_base;
        __le32  bda_rc_tx_bd_num;
        u8      bda_ep_link_state;
        u8      bda_rc_link_state;
        u8      bda_rc_msi_enabled;
        u8      reserved2;
        __le32  bda_ep_next_pkt;
        struct vmac_pkt_info request[QTN_PCIE_RC_TX_QUEUE_LEN];
        struct qtnf_shm_ipc_region bda_shm_reg1 __aligned(4096);
        struct qtnf_shm_ipc_region bda_shm_reg2 __aligned(4096);
} __packed;

struct qtnf_pcie_topaz_state {
        struct qtnf_pcie_bus_priv base;
        struct qtnf_topaz_bda __iomem *bda;

        dma_addr_t dma_msi_dummy;
        u32 dma_msi_imwr;

        struct qtnf_topaz_tx_bd *tx_bd_vbase;
        struct qtnf_topaz_rx_bd *rx_bd_vbase;

        __le32 __iomem *ep_next_rx_pkt;
        __le32 __iomem *txqueue_wake;
        __le32 __iomem *ep_pmstate;

        unsigned long rx_pkt_count;
};

static void qtnf_deassert_intx(struct qtnf_pcie_topaz_state *ts)
{
        void __iomem *reg = ts->base.sysctl_bar + TOPAZ_PCIE_CFG0_OFFSET;
        u32 cfg;

        cfg = readl(reg);
        cfg &= ~TOPAZ_ASSERT_INTX;
        qtnf_non_posted_write(cfg, reg);
}

static inline int qtnf_topaz_intx_asserted(struct qtnf_pcie_topaz_state *ts)
{
        void __iomem *reg = ts->base.sysctl_bar + TOPAZ_PCIE_CFG0_OFFSET;
        u32 cfg = readl(reg);

        return !!(cfg & TOPAZ_ASSERT_INTX);
}

static void qtnf_topaz_reset_ep(struct qtnf_pcie_topaz_state *ts)
{
        writel(TOPAZ_IPC_IRQ_WORD(TOPAZ_RC_RST_EP_IRQ),
               TOPAZ_LH_IPC4_INT(ts->base.sysctl_bar));
        msleep(QTN_EP_RESET_WAIT_MS);
        pci_restore_state(ts->base.pdev);
}

static void setup_rx_irqs(struct qtnf_pcie_topaz_state *ts)
{
        void __iomem *reg = PCIE_DMA_WR_DONE_IMWR_ADDR_LOW(ts->base.dmareg_bar);

        ts->dma_msi_imwr = readl(reg);
}

static void enable_rx_irqs(struct qtnf_pcie_topaz_state *ts)
{
        void __iomem *reg = PCIE_DMA_WR_DONE_IMWR_ADDR_LOW(ts->base.dmareg_bar);

        qtnf_non_posted_write(ts->dma_msi_imwr, reg);
}

static void disable_rx_irqs(struct qtnf_pcie_topaz_state *ts)
{
        void __iomem *reg = PCIE_DMA_WR_DONE_IMWR_ADDR_LOW(ts->base.dmareg_bar);

        qtnf_non_posted_write(QTN_HOST_LO32(ts->dma_msi_dummy), reg);
}

static void qtnf_topaz_ipc_gen_ep_int(void *arg)
{
        struct qtnf_pcie_topaz_state *ts = arg;

        writel(TOPAZ_IPC_IRQ_WORD(TOPAZ_RC_CTRL_IRQ),
               TOPAZ_CTL_M2L_INT(ts->base.sysctl_bar));
}

static int qtnf_is_state(__le32 __iomem *reg, u32 state)
{
        u32 s = readl(reg);

        return (s == state);
}

static void qtnf_set_state(__le32 __iomem *reg, u32 state)
{
        qtnf_non_posted_write(state, reg);
}

static int qtnf_poll_state(__le32 __iomem *reg, u32 state, u32 delay_in_ms)
{
        u32 timeout = 0;

        while ((qtnf_is_state(reg, state) == 0)) {
                usleep_range(1000, 1200);
                if (++timeout > delay_in_ms)
                        return -1;
        }

        return 0;
}

static int topaz_alloc_bd_table(struct qtnf_pcie_topaz_state *ts,
                                struct qtnf_topaz_bda __iomem *bda)
{
        struct qtnf_extra_bd_params __iomem *extra_params;
        struct qtnf_pcie_bus_priv *priv = &ts->base;
        dma_addr_t paddr;
        void *vaddr;
        int len;
        int i;

        /* bd table */

        len = priv->tx_bd_num * sizeof(struct qtnf_topaz_tx_bd) +
                priv->rx_bd_num * sizeof(struct qtnf_topaz_rx_bd) +
                        sizeof(struct qtnf_extra_bd_params);

        vaddr = dmam_alloc_coherent(&priv->pdev->dev, len, &paddr, GFP_KERNEL);
        if (!vaddr)
                return -ENOMEM;

        /* tx bd */

        ts->tx_bd_vbase = vaddr;
        qtnf_non_posted_write(paddr, &bda->bda_rc_tx_bd_base);

        for (i = 0; i < priv->tx_bd_num; i++)
                ts->tx_bd_vbase[i].info |= cpu_to_le32(QTN_BD_EMPTY);

        pr_debug("TX descriptor table: vaddr=0x%p paddr=%pad\n", vaddr, &paddr);

        priv->tx_bd_r_index = 0;
        priv->tx_bd_w_index = 0;

        /* rx bd */

        vaddr = ((struct qtnf_topaz_tx_bd *)vaddr) + priv->tx_bd_num;
        paddr += priv->tx_bd_num * sizeof(struct qtnf_topaz_tx_bd);

        ts->rx_bd_vbase = vaddr;
        qtnf_non_posted_write(paddr, &bda->bda_rc_rx_bd_base);

        pr_debug("RX descriptor table: vaddr=0x%p paddr=%pad\n", vaddr, &paddr);

        /* extra shared params */

        vaddr = ((struct qtnf_topaz_rx_bd *)vaddr) + priv->rx_bd_num;
        paddr += priv->rx_bd_num * sizeof(struct qtnf_topaz_rx_bd);

        extra_params = (struct qtnf_extra_bd_params __iomem *)vaddr;

        ts->ep_next_rx_pkt = &extra_params->param1;
        qtnf_non_posted_write(paddr + QTNF_BD_PARAM_OFFSET(1),
                              &bda->bda_ep_next_pkt);
        ts->txqueue_wake = &extra_params->param2;
        ts->ep_pmstate = &extra_params->param3;
        ts->dma_msi_dummy = paddr + QTNF_BD_PARAM_OFFSET(4);

        return 0;
}

static int
topaz_skb2rbd_attach(struct qtnf_pcie_topaz_state *ts, u16 index, u32 wrap)
{
        struct qtnf_topaz_rx_bd *rxbd = &ts->rx_bd_vbase[index];
        struct sk_buff *skb;
        dma_addr_t paddr;

        skb = netdev_alloc_skb_ip_align(NULL, SKB_BUF_SIZE);
        if (!skb) {
                ts->base.rx_skb[index] = NULL;
                return -ENOMEM;
        }

        ts->base.rx_skb[index] = skb;

        paddr = dma_map_single(&ts->base.pdev->dev, skb->data, SKB_BUF_SIZE,
                               DMA_FROM_DEVICE);
        if (dma_mapping_error(&ts->base.pdev->dev, paddr)) {
                pr_err("skb mapping error: %pad\n", &paddr);
                return -ENOMEM;
        }

        rxbd->addr = cpu_to_le32(QTN_HOST_LO32(paddr));
        rxbd->info = cpu_to_le32(QTN_BD_EMPTY | wrap);

        ts->base.rx_bd_w_index = index;

        return 0;
}

static int topaz_alloc_rx_buffers(struct qtnf_pcie_topaz_state *ts)
{
        u16 i;
        int ret = 0;

        memset(ts->rx_bd_vbase, 0x0,
               ts->base.rx_bd_num * sizeof(struct qtnf_topaz_rx_bd));

        for (i = 0; i < ts->base.rx_bd_num; i++) {
                ret = topaz_skb2rbd_attach(ts, i, 0);
                if (ret)
                        break;
        }

        ts->rx_bd_vbase[ts->base.rx_bd_num - 1].info |=
                                                cpu_to_le32(QTN_BD_WRAP);

        return ret;
}

/* all rx/tx activity should have ceased before calling this function */
static void qtnf_topaz_free_xfer_buffers(struct qtnf_pcie_topaz_state *ts)
{
        struct qtnf_pcie_bus_priv *priv = &ts->base;
        struct qtnf_topaz_rx_bd *rxbd;
        struct qtnf_topaz_tx_bd *txbd;
        struct sk_buff *skb;
        dma_addr_t paddr;
        int i;

        /* free rx buffers */
        for (i = 0; i < priv->rx_bd_num; i++) {
                if (priv->rx_skb && priv->rx_skb[i]) {
                        rxbd = &ts->rx_bd_vbase[i];
                        skb = priv->rx_skb[i];
                        paddr = QTN_HOST_ADDR(0x0, le32_to_cpu(rxbd->addr));
                        dma_unmap_single(&priv->pdev->dev, paddr,
                                         SKB_BUF_SIZE, DMA_FROM_DEVICE);
                        dev_kfree_skb_any(skb);
                        priv->rx_skb[i] = NULL;
                        rxbd->addr = 0;
                        rxbd->info = 0;
                }
        }

        /* free tx buffers */
        for (i = 0; i < priv->tx_bd_num; i++) {
                if (priv->tx_skb && priv->tx_skb[i]) {
                        txbd = &ts->tx_bd_vbase[i];
                        skb = priv->tx_skb[i];
                        paddr = QTN_HOST_ADDR(0x0, le32_to_cpu(txbd->addr));
                        dma_unmap_single(&priv->pdev->dev, paddr,
                                         SKB_BUF_SIZE, DMA_TO_DEVICE);
                        dev_kfree_skb_any(skb);
                        priv->tx_skb[i] = NULL;
                        txbd->addr = 0;
                        txbd->info = 0;
                }
        }
}

static int qtnf_pcie_topaz_init_xfer(struct qtnf_pcie_topaz_state *ts,
                                     unsigned int tx_bd_size,
                                     unsigned int rx_bd_size)
{
        struct qtnf_topaz_bda __iomem *bda = ts->bda;
        struct qtnf_pcie_bus_priv *priv = &ts->base;
        int ret;

        if (tx_bd_size == 0)
                tx_bd_size = TOPAZ_TX_BD_SIZE_DEFAULT;

        /* check TX BD queue max length according to struct qtnf_topaz_bda */
        if (tx_bd_size > QTN_PCIE_RC_TX_QUEUE_LEN) {
                pr_warn("TX BD queue cannot exceed %d\n",
                        QTN_PCIE_RC_TX_QUEUE_LEN);
                tx_bd_size = QTN_PCIE_RC_TX_QUEUE_LEN;
        }

        priv->tx_bd_num = tx_bd_size;
        qtnf_non_posted_write(priv->tx_bd_num, &bda->bda_rc_tx_bd_num);

        if (rx_bd_size == 0)
                rx_bd_size = TOPAZ_RX_BD_SIZE_DEFAULT;

        if (rx_bd_size > TOPAZ_RX_BD_SIZE_DEFAULT) {
                pr_warn("RX BD queue cannot exceed %d\n",
                        TOPAZ_RX_BD_SIZE_DEFAULT);
                rx_bd_size = TOPAZ_RX_BD_SIZE_DEFAULT;
        }

        priv->rx_bd_num = rx_bd_size;
        qtnf_non_posted_write(priv->rx_bd_num, &bda->bda_rc_rx_bd_num);

        priv->rx_bd_w_index = 0;
        priv->rx_bd_r_index = 0;

        ret = qtnf_pcie_alloc_skb_array(priv);
        if (ret) {
                pr_err("failed to allocate skb array\n");
                return ret;
        }

        ret = topaz_alloc_bd_table(ts, bda);
        if (ret) {
                pr_err("failed to allocate bd table\n");
                return ret;
        }

        ret = topaz_alloc_rx_buffers(ts);
        if (ret) {
                pr_err("failed to allocate rx buffers\n");
                return ret;
        }

        return ret;
}

static void qtnf_topaz_data_tx_reclaim(struct qtnf_pcie_topaz_state *ts)
{
        struct qtnf_pcie_bus_priv *priv = &ts->base;
        struct qtnf_topaz_tx_bd *txbd;
        struct sk_buff *skb;
        unsigned long flags;
        dma_addr_t paddr;
        u32 tx_done_index;
        int count = 0;
        int i;

        spin_lock_irqsave(&priv->tx_reclaim_lock, flags);

        tx_done_index = readl(ts->ep_next_rx_pkt);
        i = priv->tx_bd_r_index;

        if (CIRC_CNT(priv->tx_bd_w_index, tx_done_index, priv->tx_bd_num))
                writel(TOPAZ_IPC_IRQ_WORD(TOPAZ_RC_TX_DONE_IRQ),
                       TOPAZ_LH_IPC4_INT(priv->sysctl_bar));

        while (CIRC_CNT(tx_done_index, i, priv->tx_bd_num)) {
                skb = priv->tx_skb[i];

                if (likely(skb)) {
                        txbd = &ts->tx_bd_vbase[i];
                        paddr = QTN_HOST_ADDR(0x0, le32_to_cpu(txbd->addr));
                        dma_unmap_single(&priv->pdev->dev, paddr, skb->len,
                                         DMA_TO_DEVICE);

                        if (skb->dev) {
                                dev_sw_netstats_tx_add(skb->dev, 1, skb->len);
                                if (unlikely(priv->tx_stopped)) {
                                        qtnf_wake_all_queues(skb->dev);
                                        priv->tx_stopped = 0;
                                }
                        }

                        dev_kfree_skb_any(skb);
                }

                priv->tx_skb[i] = NULL;
                count++;

                if (++i >= priv->tx_bd_num)
                        i = 0;
        }

        priv->tx_reclaim_done += count;
        priv->tx_reclaim_req++;
        priv->tx_bd_r_index = i;

        spin_unlock_irqrestore(&priv->tx_reclaim_lock, flags);
}

static void qtnf_try_stop_xmit(struct qtnf_bus *bus, struct net_device *ndev)
{
        struct qtnf_pcie_topaz_state *ts = (void *)get_bus_priv(bus);

        if (ndev) {
                netif_tx_stop_all_queues(ndev);
                ts->base.tx_stopped = 1;
        }

        writel(0x0, ts->txqueue_wake);

        /* sync up tx queue status before generating interrupt */
        dma_wmb();

        /* send irq to card: tx stopped */
        writel(TOPAZ_IPC_IRQ_WORD(TOPAZ_RC_TX_STOP_IRQ),
               TOPAZ_LH_IPC4_INT(ts->base.sysctl_bar));

        /* schedule reclaim attempt */
        tasklet_hi_schedule(&ts->base.reclaim_tq);
}

static void qtnf_try_wake_xmit(struct qtnf_bus *bus, struct net_device *ndev)
{
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);
        int ready;

        ready = readl(ts->txqueue_wake);
        if (ready) {
                netif_wake_queue(ndev);
        } else {
                /* re-send irq to card: tx stopped */
                writel(TOPAZ_IPC_IRQ_WORD(TOPAZ_RC_TX_STOP_IRQ),
                       TOPAZ_LH_IPC4_INT(ts->base.sysctl_bar));
        }
}

static int qtnf_tx_queue_ready(struct qtnf_pcie_topaz_state *ts)
{
        struct qtnf_pcie_bus_priv *priv = &ts->base;

        if (!CIRC_SPACE(priv->tx_bd_w_index, priv->tx_bd_r_index,
                        priv->tx_bd_num)) {
                qtnf_topaz_data_tx_reclaim(ts);

                if (!CIRC_SPACE(priv->tx_bd_w_index, priv->tx_bd_r_index,
                                priv->tx_bd_num)) {
                        priv->tx_full_count++;
                        return 0;
                }
        }

        return 1;
}

static int qtnf_pcie_data_tx(struct qtnf_bus *bus, struct sk_buff *skb,
                             unsigned int macid, unsigned int vifid)
{
        struct qtnf_pcie_topaz_state *ts = (void *)get_bus_priv(bus);
        struct qtnf_pcie_bus_priv *priv = &ts->base;
        struct qtnf_topaz_bda __iomem *bda = ts->bda;
        struct qtnf_topaz_tx_bd *txbd;
        dma_addr_t skb_paddr;
        unsigned long flags;
        int ret = 0;
        int len;
        int i;

        spin_lock_irqsave(&priv->tx_lock, flags);

        if (!qtnf_tx_queue_ready(ts)) {
                qtnf_try_stop_xmit(bus, skb->dev);
                spin_unlock_irqrestore(&priv->tx_lock, flags);
                return NETDEV_TX_BUSY;
        }

        i = priv->tx_bd_w_index;
        priv->tx_skb[i] = skb;
        len = skb->len;

        skb_paddr = dma_map_single(&priv->pdev->dev, skb->data, skb->len,
                                   DMA_TO_DEVICE);
        if (dma_mapping_error(&priv->pdev->dev, skb_paddr)) {
                ret = -ENOMEM;
                goto tx_done;
        }

        txbd = &ts->tx_bd_vbase[i];
        txbd->addr = cpu_to_le32(QTN_HOST_LO32(skb_paddr));

        writel(QTN_HOST_LO32(skb_paddr), &bda->request[i].addr);
        writel(len | QTN_PCIE_TX_VALID_PKT, &bda->request[i].info);

        /* sync up descriptor updates before generating interrupt */
        dma_wmb();

        /* generate irq to card: tx done */
        writel(TOPAZ_IPC_IRQ_WORD(TOPAZ_RC_TX_DONE_IRQ),
               TOPAZ_LH_IPC4_INT(priv->sysctl_bar));

        if (++i >= priv->tx_bd_num)
                i = 0;

        priv->tx_bd_w_index = i;

tx_done:
        if (ret) {
                if (skb->dev)
                        skb->dev->stats.tx_dropped++;
                dev_kfree_skb_any(skb);
        }

        priv->tx_done_count++;
        spin_unlock_irqrestore(&priv->tx_lock, flags);

        qtnf_topaz_data_tx_reclaim(ts);

        return NETDEV_TX_OK;
}

static irqreturn_t qtnf_pcie_topaz_interrupt(int irq, void *data)
{
        struct qtnf_bus *bus = (struct qtnf_bus *)data;
        struct qtnf_pcie_topaz_state *ts = (void *)get_bus_priv(bus);
        struct qtnf_pcie_bus_priv *priv = &ts->base;

        if (!priv->msi_enabled && !qtnf_topaz_intx_asserted(ts))
                return IRQ_NONE;

        if (!priv->msi_enabled)
                qtnf_deassert_intx(ts);

        priv->pcie_irq_count++;

        qtnf_shm_ipc_irq_handler(&priv->shm_ipc_ep_in);
        qtnf_shm_ipc_irq_handler(&priv->shm_ipc_ep_out);

        if (napi_schedule_prep(&bus->mux_napi)) {
                disable_rx_irqs(ts);
                __napi_schedule(&bus->mux_napi);
        }

        tasklet_hi_schedule(&priv->reclaim_tq);

        return IRQ_HANDLED;
}

static int qtnf_rx_data_ready(struct qtnf_pcie_topaz_state *ts)
{
        u16 index = ts->base.rx_bd_r_index;
        struct qtnf_topaz_rx_bd *rxbd;
        u32 descw;

        rxbd = &ts->rx_bd_vbase[index];
        descw = le32_to_cpu(rxbd->info);

        if (descw & QTN_BD_EMPTY)
                return 0;

        return 1;
}

static int qtnf_topaz_rx_poll(struct napi_struct *napi, int budget)
{
        struct qtnf_bus *bus = container_of(napi, struct qtnf_bus, mux_napi);
        struct qtnf_pcie_topaz_state *ts = (void *)get_bus_priv(bus);
        struct qtnf_pcie_bus_priv *priv = &ts->base;
        struct net_device *ndev = NULL;
        struct sk_buff *skb = NULL;
        int processed = 0;
        struct qtnf_topaz_rx_bd *rxbd;
        dma_addr_t skb_paddr;
        int consume;
        u32 descw;
        u32 poffset;
        u32 psize;
        u16 r_idx;
        u16 w_idx;
        int ret;

        while (processed < budget) {
                if (!qtnf_rx_data_ready(ts))
                        goto rx_out;

                r_idx = priv->rx_bd_r_index;
                rxbd = &ts->rx_bd_vbase[r_idx];
                descw = le32_to_cpu(rxbd->info);

                skb = priv->rx_skb[r_idx];
                poffset = QTN_GET_OFFSET(descw);
                psize = QTN_GET_LEN(descw);
                consume = 1;

                if (descw & QTN_BD_EMPTY) {
                        pr_warn("skip invalid rxbd[%d]\n", r_idx);
                        consume = 0;
                }

                if (!skb) {
                        pr_warn("skip missing rx_skb[%d]\n", r_idx);
                        consume = 0;
                }

                if (skb && (skb_tailroom(skb) <  psize)) {
                        pr_err("skip packet with invalid length: %u > %u\n",
                               psize, skb_tailroom(skb));
                        consume = 0;
                }

                if (skb) {
                        skb_paddr = QTN_HOST_ADDR(0x0, le32_to_cpu(rxbd->addr));
                        dma_unmap_single(&priv->pdev->dev, skb_paddr,
                                         SKB_BUF_SIZE, DMA_FROM_DEVICE);
                }

                if (consume) {
                        skb_reserve(skb, poffset);
                        skb_put(skb, psize);
                        ndev = qtnf_classify_skb(bus, skb);
                        if (likely(ndev)) {
                                dev_sw_netstats_rx_add(ndev, skb->len);
                                skb->protocol = eth_type_trans(skb, ndev);
                                netif_receive_skb(skb);
                        } else {
                                pr_debug("drop untagged skb\n");
                                bus->mux_dev->stats.rx_dropped++;
                                dev_kfree_skb_any(skb);
                        }
                } else {
                        if (skb) {
                                bus->mux_dev->stats.rx_dropped++;
                                dev_kfree_skb_any(skb);
                        }
                }

                /* notify card about recv packets once per several packets */
                if (((++ts->rx_pkt_count) & RX_DONE_INTR_MSK) == 0)
                        writel(TOPAZ_IPC_IRQ_WORD(TOPAZ_RC_RX_DONE_IRQ),
                               TOPAZ_LH_IPC4_INT(priv->sysctl_bar));

                priv->rx_skb[r_idx] = NULL;
                if (++r_idx >= priv->rx_bd_num)
                        r_idx = 0;

                priv->rx_bd_r_index = r_idx;

                /* repalce processed buffer by a new one */
                w_idx = priv->rx_bd_w_index;
                while (CIRC_SPACE(priv->rx_bd_w_index, priv->rx_bd_r_index,
                                  priv->rx_bd_num) > 0) {
                        if (++w_idx >= priv->rx_bd_num)
                                w_idx = 0;

                        ret = topaz_skb2rbd_attach(ts, w_idx,
                                                   descw & QTN_BD_WRAP);
                        if (ret) {
                                pr_err("failed to allocate new rx_skb[%d]\n",
                                       w_idx);
                                break;
                        }
                }

                processed++;
        }

rx_out:
        if (processed < budget) {
                napi_complete(napi);
                enable_rx_irqs(ts);
        }

        return processed;
}

static void
qtnf_pcie_data_tx_timeout(struct qtnf_bus *bus, struct net_device *ndev)
{
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);

        qtnf_try_wake_xmit(bus, ndev);
        tasklet_hi_schedule(&ts->base.reclaim_tq);
}

static void qtnf_pcie_data_rx_start(struct qtnf_bus *bus)
{
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);

        napi_enable(&bus->mux_napi);
        enable_rx_irqs(ts);
}

static void qtnf_pcie_data_rx_stop(struct qtnf_bus *bus)
{
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);

        disable_rx_irqs(ts);
        napi_disable(&bus->mux_napi);
}

static struct qtnf_bus_ops qtnf_pcie_topaz_bus_ops = {
        /* control path methods */
        .control_tx     = qtnf_pcie_control_tx,

        /* data path methods */
        .data_tx                = qtnf_pcie_data_tx,
        .data_tx_timeout        = qtnf_pcie_data_tx_timeout,
        .data_rx_start          = qtnf_pcie_data_rx_start,
        .data_rx_stop           = qtnf_pcie_data_rx_stop,
};

static int qtnf_dbg_irq_stats(struct seq_file *s, void *data)
{
        struct qtnf_bus *bus = dev_get_drvdata(s->private);
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);

        seq_printf(s, "pcie_irq_count(%u)\n", ts->base.pcie_irq_count);

        return 0;
}

static int qtnf_dbg_pkt_stats(struct seq_file *s, void *data)
{
        struct qtnf_bus *bus = dev_get_drvdata(s->private);
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);
        struct qtnf_pcie_bus_priv *priv = &ts->base;
        u32 tx_done_index = readl(ts->ep_next_rx_pkt);

        seq_printf(s, "tx_full_count(%u)\n", priv->tx_full_count);
        seq_printf(s, "tx_done_count(%u)\n", priv->tx_done_count);
        seq_printf(s, "tx_reclaim_done(%u)\n", priv->tx_reclaim_done);
        seq_printf(s, "tx_reclaim_req(%u)\n", priv->tx_reclaim_req);

        seq_printf(s, "tx_bd_r_index(%u)\n", priv->tx_bd_r_index);
        seq_printf(s, "tx_done_index(%u)\n", tx_done_index);
        seq_printf(s, "tx_bd_w_index(%u)\n", priv->tx_bd_w_index);

        seq_printf(s, "tx host queue len(%u)\n",
                   CIRC_CNT(priv->tx_bd_w_index, priv->tx_bd_r_index,
                            priv->tx_bd_num));
        seq_printf(s, "tx reclaim queue len(%u)\n",
                   CIRC_CNT(tx_done_index, priv->tx_bd_r_index,
                            priv->tx_bd_num));
        seq_printf(s, "tx card queue len(%u)\n",
                   CIRC_CNT(priv->tx_bd_w_index, tx_done_index,
                            priv->tx_bd_num));

        seq_printf(s, "rx_bd_r_index(%u)\n", priv->rx_bd_r_index);
        seq_printf(s, "rx_bd_w_index(%u)\n", priv->rx_bd_w_index);
        seq_printf(s, "rx alloc queue len(%u)\n",
                   CIRC_SPACE(priv->rx_bd_w_index, priv->rx_bd_r_index,
                              priv->rx_bd_num));

        return 0;
}

static void qtnf_reset_dma_offset(struct qtnf_pcie_topaz_state *ts)
{
        struct qtnf_topaz_bda __iomem *bda = ts->bda;
        u32 offset = readl(&bda->bda_dma_offset);

        if ((offset & PCIE_DMA_OFFSET_ERROR_MASK) != PCIE_DMA_OFFSET_ERROR)
                return;

        writel(0x0, &bda->bda_dma_offset);
}

static int qtnf_pcie_endian_detect(struct qtnf_pcie_topaz_state *ts)
{
        struct qtnf_topaz_bda __iomem *bda = ts->bda;
        u32 timeout = 0;
        u32 endian;
        int ret = 0;

        writel(QTN_PCI_ENDIAN_DETECT_DATA, &bda->bda_pci_endian);

        /* flush endian modifications before status update */
        dma_wmb();

        writel(QTN_PCI_ENDIAN_VALID_STATUS, &bda->bda_pci_pre_status);

        while (readl(&bda->bda_pci_post_status) !=
               QTN_PCI_ENDIAN_VALID_STATUS) {
                usleep_range(1000, 1200);
                if (++timeout > QTN_FW_DL_TIMEOUT_MS) {
                        pr_err("card endianness detection timed out\n");
                        ret = -ETIMEDOUT;
                        goto endian_out;
                }
        }

        /* do not read before status is updated */
        dma_rmb();

        endian = readl(&bda->bda_pci_endian);
        WARN(endian != QTN_PCI_LITTLE_ENDIAN,
             "%s: unexpected card endianness", __func__);

endian_out:
        writel(0, &bda->bda_pci_pre_status);
        writel(0, &bda->bda_pci_post_status);
        writel(0, &bda->bda_pci_endian);

        return ret;
}

static int qtnf_pre_init_ep(struct qtnf_bus *bus)
{
        struct qtnf_pcie_topaz_state *ts = (void *)get_bus_priv(bus);
        struct qtnf_topaz_bda __iomem *bda = ts->bda;
        u32 flags;
        int ret;

        ret = qtnf_pcie_endian_detect(ts);
        if (ret < 0) {
                pr_err("failed to detect card endianness\n");
                return ret;
        }

        writeb(ts->base.msi_enabled, &ts->bda->bda_rc_msi_enabled);
        qtnf_reset_dma_offset(ts);

        /* notify card about driver type and boot mode */
        flags = readl(&bda->bda_flags) | QTN_BDA_HOST_QLINK_DRV;

        if (ts->base.flashboot)
                flags |= QTN_BDA_FLASH_BOOT;
        else
                flags &= ~QTN_BDA_FLASH_BOOT;

        writel(flags, &bda->bda_flags);

        qtnf_set_state(&ts->bda->bda_bootstate, QTN_BDA_FW_HOST_RDY);
        if (qtnf_poll_state(&ts->bda->bda_bootstate, QTN_BDA_FW_TARGET_RDY,
                            QTN_FW_DL_TIMEOUT_MS)) {
                pr_err("card is not ready to boot...\n");
                return -ETIMEDOUT;
        }

        return ret;
}

static int qtnf_post_init_ep(struct qtnf_pcie_topaz_state *ts)
{
        struct pci_dev *pdev = ts->base.pdev;

        setup_rx_irqs(ts);
        disable_rx_irqs(ts);

        if (qtnf_poll_state(&ts->bda->bda_bootstate, QTN_BDA_FW_QLINK_DONE,
                            QTN_FW_QLINK_TIMEOUT_MS))
                return -ETIMEDOUT;

        enable_irq(pdev->irq);
        return 0;
}

static int
qtnf_ep_fw_load(struct qtnf_pcie_topaz_state *ts, const u8 *fw, u32 fw_size)
{
        struct qtnf_topaz_bda __iomem *bda = ts->bda;
        struct pci_dev *pdev = ts->base.pdev;
        u32 remaining = fw_size;
        u8 *curr = (u8 *)fw;
        u32 blksize;
        u32 nblocks;
        u32 offset;
        u32 count;
        u32 size;
        dma_addr_t paddr;
        void *data;
        int ret = 0;

        pr_debug("FW upload started: fw_addr = 0x%p, size=%d\n", fw, fw_size);

        blksize = ts->base.fw_blksize;

        if (blksize < PAGE_SIZE)
                blksize = PAGE_SIZE;

        while (blksize >= PAGE_SIZE) {
                pr_debug("allocating %u bytes to upload FW\n", blksize);
                data = dma_alloc_coherent(&pdev->dev, blksize,
                                          &paddr, GFP_KERNEL);
                if (data)
                        break;
                blksize /= 2;
        }

        if (!data) {
                pr_err("failed to allocate DMA buffer for FW upload\n");
                ret = -ENOMEM;
                goto fw_load_out;
        }

        nblocks = NBLOCKS(fw_size, blksize);
        offset = readl(&bda->bda_dma_offset);

        qtnf_set_state(&ts->bda->bda_bootstate, QTN_BDA_FW_HOST_LOAD);
        if (qtnf_poll_state(&ts->bda->bda_bootstate, QTN_BDA_FW_EP_RDY,
                            QTN_FW_DL_TIMEOUT_MS)) {
                pr_err("card is not ready to download FW\n");
                ret = -ETIMEDOUT;
                goto fw_load_map;
        }

        for (count = 0 ; count < nblocks; count++) {
                size = (remaining > blksize) ? blksize : remaining;

                memcpy(data, curr, size);
                qtnf_non_posted_write(paddr + offset, &bda->bda_img);
                qtnf_non_posted_write(size, &bda->bda_img_size);

                pr_debug("chunk[%u] VA[0x%p] PA[%pad] sz[%u]\n",
                         count, (void *)curr, &paddr, size);

                qtnf_set_state(&ts->bda->bda_bootstate, QTN_BDA_FW_BLOCK_RDY);
                if (qtnf_poll_state(&ts->bda->bda_bootstate,
                                    QTN_BDA_FW_BLOCK_DONE,
                                    QTN_FW_DL_TIMEOUT_MS)) {
                        pr_err("confirmation for block #%d timed out\n", count);
                        ret = -ETIMEDOUT;
                        goto fw_load_map;
                }

                remaining = (remaining < size) ? remaining : (remaining - size);
                curr += size;
        }

        /* upload completion mark: zero-sized block */
        qtnf_non_posted_write(0, &bda->bda_img);
        qtnf_non_posted_write(0, &bda->bda_img_size);

        qtnf_set_state(&ts->bda->bda_bootstate, QTN_BDA_FW_BLOCK_RDY);
        if (qtnf_poll_state(&ts->bda->bda_bootstate, QTN_BDA_FW_BLOCK_DONE,
                            QTN_FW_DL_TIMEOUT_MS)) {
                pr_err("confirmation for the last block timed out\n");
                ret = -ETIMEDOUT;
                goto fw_load_map;
        }

        /* RC is done */
        qtnf_set_state(&ts->bda->bda_bootstate, QTN_BDA_FW_BLOCK_END);
        if (qtnf_poll_state(&ts->bda->bda_bootstate, QTN_BDA_FW_LOAD_DONE,
                            QTN_FW_DL_TIMEOUT_MS)) {
                pr_err("confirmation for FW upload completion timed out\n");
                ret = -ETIMEDOUT;
                goto fw_load_map;
        }

        pr_debug("FW upload completed: totally sent %d blocks\n", count);

fw_load_map:
        dma_free_coherent(&pdev->dev, blksize, data, paddr);

fw_load_out:
        return ret;
}

static int qtnf_topaz_fw_upload(struct qtnf_pcie_topaz_state *ts,
                                const char *fwname)
{
        const struct firmware *fw;
        struct pci_dev *pdev = ts->base.pdev;
        int ret;

        if (qtnf_poll_state(&ts->bda->bda_bootstate,
                            QTN_BDA_FW_LOAD_RDY,
                            QTN_FW_DL_TIMEOUT_MS)) {
                pr_err("%s: card is not ready\n", fwname);
                return -1;
        }

        pr_info("starting firmware upload: %s\n", fwname);

        ret = request_firmware(&fw, fwname, &pdev->dev);
        if (ret < 0) {
                pr_err("%s: request_firmware error %d\n", fwname, ret);
                return -1;
        }

        ret = qtnf_ep_fw_load(ts, fw->data, fw->size);
        release_firmware(fw);

        if (ret)
                pr_err("%s: FW upload error\n", fwname);

        return ret;
}

static void qtnf_topaz_fw_work_handler(struct work_struct *work)
{
        struct qtnf_bus *bus = container_of(work, struct qtnf_bus, fw_work);
        struct qtnf_pcie_topaz_state *ts = (void *)get_bus_priv(bus);
        int bootloader_needed = readl(&ts->bda->bda_flags) & QTN_BDA_XMIT_UBOOT;
        struct pci_dev *pdev = ts->base.pdev;
        int ret;

        qtnf_set_state(&ts->bda->bda_bootstate, QTN_BDA_FW_TARGET_BOOT);

        if (bootloader_needed) {
                ret = qtnf_topaz_fw_upload(ts, QTN_PCI_TOPAZ_BOOTLD_NAME);
                if (ret)
                        goto fw_load_exit;

                ret = qtnf_pre_init_ep(bus);
                if (ret)
                        goto fw_load_exit;

                qtnf_set_state(&ts->bda->bda_bootstate,
                               QTN_BDA_FW_TARGET_BOOT);
        }

        if (ts->base.flashboot) {
                pr_info("booting firmware from flash\n");

                ret = qtnf_poll_state(&ts->bda->bda_bootstate,
                                      QTN_BDA_FW_FLASH_BOOT,
                                      QTN_FW_DL_TIMEOUT_MS);
                if (ret)
                        goto fw_load_exit;
        } else {
                ret = qtnf_topaz_fw_upload(ts, QTN_PCI_TOPAZ_FW_NAME);
                if (ret)
                        goto fw_load_exit;

                qtnf_set_state(&ts->bda->bda_bootstate, QTN_BDA_FW_START);
                ret = qtnf_poll_state(&ts->bda->bda_bootstate,
                                      QTN_BDA_FW_CONFIG,
                                      QTN_FW_QLINK_TIMEOUT_MS);
                if (ret) {
                        pr_err("FW bringup timed out\n");
                        goto fw_load_exit;
                }

                qtnf_set_state(&ts->bda->bda_bootstate, QTN_BDA_FW_RUN);
                ret = qtnf_poll_state(&ts->bda->bda_bootstate,
                                      QTN_BDA_FW_RUNNING,
                                      QTN_FW_QLINK_TIMEOUT_MS);
                if (ret) {
                        pr_err("card bringup timed out\n");
                        goto fw_load_exit;
                }
        }

        ret = qtnf_post_init_ep(ts);
        if (ret) {
                pr_err("FW runtime failure\n");
                goto fw_load_exit;
        }

        pr_info("firmware is up and running\n");

        ret = qtnf_pcie_fw_boot_done(bus);
        if (ret)
                goto fw_load_exit;

        qtnf_debugfs_add_entry(bus, "pkt_stats", qtnf_dbg_pkt_stats);
        qtnf_debugfs_add_entry(bus, "irq_stats", qtnf_dbg_irq_stats);

fw_load_exit:
        put_device(&pdev->dev);
}

static void qtnf_reclaim_tasklet_fn(struct tasklet_struct *t)
{
        struct qtnf_pcie_topaz_state *ts = from_tasklet(ts, t, base.reclaim_tq);

        qtnf_topaz_data_tx_reclaim(ts);
}

static u64 qtnf_topaz_dma_mask_get(void)
{
        return DMA_BIT_MASK(32);
}

static int qtnf_pcie_topaz_probe(struct qtnf_bus *bus,
                                 unsigned int tx_bd_num, unsigned int rx_bd_num)
{
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);
        struct pci_dev *pdev = ts->base.pdev;
        struct qtnf_shm_ipc_int ipc_int;
        unsigned long irqflags;
        int ret;

        bus->bus_ops = &qtnf_pcie_topaz_bus_ops;
        INIT_WORK(&bus->fw_work, qtnf_topaz_fw_work_handler);
        ts->bda = ts->base.epmem_bar;

        /* assign host msi irq before card init */
        if (ts->base.msi_enabled)
                irqflags = IRQF_NOBALANCING | IRQF_NO_AUTOEN;
        else
                irqflags = IRQF_NOBALANCING | IRQF_SHARED | IRQF_NO_AUTOEN;

        ret = devm_request_irq(&pdev->dev, pdev->irq,
                               &qtnf_pcie_topaz_interrupt,
                               irqflags, "qtnf_topaz_irq", (void *)bus);
        if (ret) {
                pr_err("failed to request pcie irq %d\n", pdev->irq);
                return ret;
        }

        ret = qtnf_pre_init_ep(bus);
        if (ret) {
                pr_err("failed to init card\n");
                return ret;
        }

        ret = qtnf_pcie_topaz_init_xfer(ts, tx_bd_num, rx_bd_num);
        if (ret) {
                pr_err("PCIE xfer init failed\n");
                return ret;
        }

        tasklet_setup(&ts->base.reclaim_tq, qtnf_reclaim_tasklet_fn);
        netif_napi_add_weight(bus->mux_dev, &bus->mux_napi,
                              qtnf_topaz_rx_poll, 10);

        ipc_int.fn = qtnf_topaz_ipc_gen_ep_int;
        ipc_int.arg = ts;
        qtnf_pcie_init_shm_ipc(&ts->base, &ts->bda->bda_shm_reg1,
                               &ts->bda->bda_shm_reg2, &ipc_int);

        return 0;
}

static void qtnf_pcie_topaz_remove(struct qtnf_bus *bus)
{
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);

        qtnf_topaz_reset_ep(ts);
        qtnf_topaz_free_xfer_buffers(ts);
}

#ifdef CONFIG_PM_SLEEP
static int qtnf_pcie_topaz_suspend(struct qtnf_bus *bus)
{
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);
        struct pci_dev *pdev = ts->base.pdev;

        writel((u32 __force)PCI_D3hot, ts->ep_pmstate);
        dma_wmb();
        writel(TOPAZ_IPC_IRQ_WORD(TOPAZ_RC_PM_EP_IRQ),
               TOPAZ_LH_IPC4_INT(ts->base.sysctl_bar));

        pci_save_state(pdev);
        pci_enable_wake(pdev, PCI_D3hot, 1);
        pci_set_power_state(pdev, PCI_D3hot);

        return 0;
}

static int qtnf_pcie_topaz_resume(struct qtnf_bus *bus)
{
        struct qtnf_pcie_topaz_state *ts = get_bus_priv(bus);
        struct pci_dev *pdev = ts->base.pdev;

        pci_set_power_state(pdev, PCI_D0);
        pci_restore_state(pdev);
        pci_enable_wake(pdev, PCI_D0, 0);

        writel((u32 __force)PCI_D0, ts->ep_pmstate);
        dma_wmb();
        writel(TOPAZ_IPC_IRQ_WORD(TOPAZ_RC_PM_EP_IRQ),
               TOPAZ_LH_IPC4_INT(ts->base.sysctl_bar));

        return 0;
}
#endif

struct qtnf_bus *qtnf_pcie_topaz_alloc(struct pci_dev *pdev)
{
        struct qtnf_bus *bus;
        struct qtnf_pcie_topaz_state *ts;

        bus = devm_kzalloc(&pdev->dev, sizeof(*bus) + sizeof(*ts), GFP_KERNEL);
        if (!bus)
                return NULL;

        ts = get_bus_priv(bus);
        ts->base.probe_cb = qtnf_pcie_topaz_probe;
        ts->base.remove_cb = qtnf_pcie_topaz_remove;
        ts->base.dma_mask_get_cb = qtnf_topaz_dma_mask_get;
#ifdef CONFIG_PM_SLEEP
        ts->base.resume_cb = qtnf_pcie_topaz_resume;
        ts->base.suspend_cb = qtnf_pcie_topaz_suspend;
#endif

        return bus;
}