root/drivers/net/ethernet/apm/xgene-v2/main.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Applied Micro X-Gene SoC Ethernet v2 Driver
 *
 * Copyright (c) 2017, Applied Micro Circuits Corporation
 * Author(s): Iyappan Subramanian <isubramanian@apm.com>
 *            Keyur Chudgar <kchudgar@apm.com>
 */

#include "main.h"

static int xge_get_resources(struct xge_pdata *pdata)
{
        struct platform_device *pdev;
        struct net_device *ndev;
        int phy_mode, ret = 0;
        struct resource *res;
        struct device *dev;

        pdev = pdata->pdev;
        dev = &pdev->dev;
        ndev = pdata->ndev;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(dev, "Resource enet_csr not defined\n");
                return -ENODEV;
        }

        pdata->resources.base_addr = devm_ioremap(dev, res->start,
                                                  resource_size(res));
        if (!pdata->resources.base_addr) {
                dev_err(dev, "Unable to retrieve ENET Port CSR region\n");
                return -ENOMEM;
        }

        if (device_get_ethdev_address(dev, ndev))
                eth_hw_addr_random(ndev);

        memcpy(ndev->perm_addr, ndev->dev_addr, ndev->addr_len);

        phy_mode = device_get_phy_mode(dev);
        if (phy_mode < 0) {
                dev_err(dev, "Unable to get phy-connection-type\n");
                return phy_mode;
        }
        pdata->resources.phy_mode = phy_mode;

        if (pdata->resources.phy_mode != PHY_INTERFACE_MODE_RGMII) {
                dev_err(dev, "Incorrect phy-connection-type specified\n");
                return -ENODEV;
        }

        ret = platform_get_irq(pdev, 0);
        if (ret < 0)
                return ret;
        pdata->resources.irq = ret;

        return 0;
}

static int xge_refill_buffers(struct net_device *ndev, u32 nbuf)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct xge_desc_ring *ring = pdata->rx_ring;
        const u8 slots = XGENE_ENET_NUM_DESC - 1;
        struct device *dev = &pdata->pdev->dev;
        struct xge_raw_desc *raw_desc;
        u64 addr_lo, addr_hi;
        u8 tail = ring->tail;
        struct sk_buff *skb;
        dma_addr_t dma_addr;
        u16 len;
        int i;

        for (i = 0; i < nbuf; i++) {
                raw_desc = &ring->raw_desc[tail];

                len = XGENE_ENET_STD_MTU;
                skb = netdev_alloc_skb(ndev, len);
                if (unlikely(!skb))
                        return -ENOMEM;

                dma_addr = dma_map_single(dev, skb->data, len, DMA_FROM_DEVICE);
                if (dma_mapping_error(dev, dma_addr)) {
                        netdev_err(ndev, "DMA mapping error\n");
                        dev_kfree_skb_any(skb);
                        return -EINVAL;
                }

                ring->pkt_info[tail].skb = skb;
                ring->pkt_info[tail].dma_addr = dma_addr;

                addr_hi = GET_BITS(NEXT_DESC_ADDRH, le64_to_cpu(raw_desc->m1));
                addr_lo = GET_BITS(NEXT_DESC_ADDRL, le64_to_cpu(raw_desc->m1));
                raw_desc->m1 = cpu_to_le64(SET_BITS(NEXT_DESC_ADDRL, addr_lo) |
                                           SET_BITS(NEXT_DESC_ADDRH, addr_hi) |
                                           SET_BITS(PKT_ADDRH,
                                                    upper_32_bits(dma_addr)));

                dma_wmb();
                raw_desc->m0 = cpu_to_le64(SET_BITS(PKT_ADDRL, dma_addr) |
                                           SET_BITS(E, 1));
                tail = (tail + 1) & slots;
        }

        ring->tail = tail;

        return 0;
}

static int xge_init_hw(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        int ret;

        ret = xge_port_reset(ndev);
        if (ret)
                return ret;

        xge_port_init(ndev);
        pdata->nbufs = NUM_BUFS;

        return 0;
}

static irqreturn_t xge_irq(const int irq, void *data)
{
        struct xge_pdata *pdata = data;

        if (napi_schedule_prep(&pdata->napi)) {
                xge_intr_disable(pdata);
                __napi_schedule(&pdata->napi);
        }

        return IRQ_HANDLED;
}

static int xge_request_irq(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        int ret;

        snprintf(pdata->irq_name, IRQ_ID_SIZE, "%s", ndev->name);

        ret = request_irq(pdata->resources.irq, xge_irq, 0, pdata->irq_name,
                          pdata);
        if (ret)
                netdev_err(ndev, "Failed to request irq %s\n", pdata->irq_name);

        return ret;
}

static void xge_free_irq(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);

        free_irq(pdata->resources.irq, pdata);
}

static bool is_tx_slot_available(struct xge_raw_desc *raw_desc)
{
        if (GET_BITS(E, le64_to_cpu(raw_desc->m0)) &&
            (GET_BITS(PKT_SIZE, le64_to_cpu(raw_desc->m0)) == SLOT_EMPTY))
                return true;

        return false;
}

static netdev_tx_t xge_start_xmit(struct sk_buff *skb, struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct device *dev = &pdata->pdev->dev;
        struct xge_desc_ring *tx_ring;
        struct xge_raw_desc *raw_desc;
        static dma_addr_t dma_addr;
        u64 addr_lo, addr_hi;
        void *pkt_buf;
        u8 tail;
        u16 len;

        tx_ring = pdata->tx_ring;
        tail = tx_ring->tail;
        len = skb_headlen(skb);
        raw_desc = &tx_ring->raw_desc[tail];

        if (!is_tx_slot_available(raw_desc)) {
                netif_stop_queue(ndev);
                return NETDEV_TX_BUSY;
        }

        /* Packet buffers should be 64B aligned */
        pkt_buf = dma_alloc_coherent(dev, XGENE_ENET_STD_MTU, &dma_addr,
                                     GFP_ATOMIC);
        if (unlikely(!pkt_buf)) {
                dev_kfree_skb_any(skb);
                return NETDEV_TX_OK;
        }
        memcpy(pkt_buf, skb->data, len);

        addr_hi = GET_BITS(NEXT_DESC_ADDRH, le64_to_cpu(raw_desc->m1));
        addr_lo = GET_BITS(NEXT_DESC_ADDRL, le64_to_cpu(raw_desc->m1));
        raw_desc->m1 = cpu_to_le64(SET_BITS(NEXT_DESC_ADDRL, addr_lo) |
                                   SET_BITS(NEXT_DESC_ADDRH, addr_hi) |
                                   SET_BITS(PKT_ADDRH,
                                            upper_32_bits(dma_addr)));

        tx_ring->pkt_info[tail].skb = skb;
        tx_ring->pkt_info[tail].dma_addr = dma_addr;
        tx_ring->pkt_info[tail].pkt_buf = pkt_buf;

        dma_wmb();

        raw_desc->m0 = cpu_to_le64(SET_BITS(PKT_ADDRL, dma_addr) |
                                   SET_BITS(PKT_SIZE, len) |
                                   SET_BITS(E, 0));
        skb_tx_timestamp(skb);
        xge_wr_csr(pdata, DMATXCTRL, 1);

        tx_ring->tail = (tail + 1) & (XGENE_ENET_NUM_DESC - 1);

        return NETDEV_TX_OK;
}

static bool is_tx_hw_done(struct xge_raw_desc *raw_desc)
{
        if (GET_BITS(E, le64_to_cpu(raw_desc->m0)) &&
            !GET_BITS(PKT_SIZE, le64_to_cpu(raw_desc->m0)))
                return true;

        return false;
}

static void xge_txc_poll(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct device *dev = &pdata->pdev->dev;
        struct xge_desc_ring *tx_ring;
        struct xge_raw_desc *raw_desc;
        dma_addr_t dma_addr;
        struct sk_buff *skb;
        void *pkt_buf;
        u32 data;
        u8 head;

        tx_ring = pdata->tx_ring;
        head = tx_ring->head;

        data = xge_rd_csr(pdata, DMATXSTATUS);
        if (!GET_BITS(TXPKTCOUNT, data))
                return;

        while (1) {
                raw_desc = &tx_ring->raw_desc[head];

                if (!is_tx_hw_done(raw_desc))
                        break;

                dma_rmb();

                skb = tx_ring->pkt_info[head].skb;
                dma_addr = tx_ring->pkt_info[head].dma_addr;
                pkt_buf = tx_ring->pkt_info[head].pkt_buf;
                pdata->stats.tx_packets++;
                pdata->stats.tx_bytes += skb->len;
                dma_free_coherent(dev, XGENE_ENET_STD_MTU, pkt_buf, dma_addr);
                dev_kfree_skb_any(skb);

                /* clear pktstart address and pktsize */
                raw_desc->m0 = cpu_to_le64(SET_BITS(E, 1) |
                                           SET_BITS(PKT_SIZE, SLOT_EMPTY));
                xge_wr_csr(pdata, DMATXSTATUS, 1);

                head = (head + 1) & (XGENE_ENET_NUM_DESC - 1);
        }

        if (netif_queue_stopped(ndev))
                netif_wake_queue(ndev);

        tx_ring->head = head;
}

static int xge_rx_poll(struct net_device *ndev, unsigned int budget)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct device *dev = &pdata->pdev->dev;
        struct xge_desc_ring *rx_ring;
        struct xge_raw_desc *raw_desc;
        struct sk_buff *skb;
        dma_addr_t dma_addr;
        int processed = 0;
        u8 head, rx_error;
        int i, ret;
        u32 data;
        u16 len;

        rx_ring = pdata->rx_ring;
        head = rx_ring->head;

        data = xge_rd_csr(pdata, DMARXSTATUS);
        if (!GET_BITS(RXPKTCOUNT, data))
                return 0;

        for (i = 0; i < budget; i++) {
                raw_desc = &rx_ring->raw_desc[head];

                if (GET_BITS(E, le64_to_cpu(raw_desc->m0)))
                        break;

                dma_rmb();

                skb = rx_ring->pkt_info[head].skb;
                rx_ring->pkt_info[head].skb = NULL;
                dma_addr = rx_ring->pkt_info[head].dma_addr;
                len = GET_BITS(PKT_SIZE, le64_to_cpu(raw_desc->m0));
                dma_unmap_single(dev, dma_addr, XGENE_ENET_STD_MTU,
                                 DMA_FROM_DEVICE);

                rx_error = GET_BITS(D, le64_to_cpu(raw_desc->m2));
                if (unlikely(rx_error)) {
                        pdata->stats.rx_errors++;
                        dev_kfree_skb_any(skb);
                        goto out;
                }

                skb_put(skb, len);
                skb->protocol = eth_type_trans(skb, ndev);

                pdata->stats.rx_packets++;
                pdata->stats.rx_bytes += len;
                napi_gro_receive(&pdata->napi, skb);
out:
                ret = xge_refill_buffers(ndev, 1);
                xge_wr_csr(pdata, DMARXSTATUS, 1);
                xge_wr_csr(pdata, DMARXCTRL, 1);

                if (ret)
                        break;

                head = (head + 1) & (XGENE_ENET_NUM_DESC - 1);
                processed++;
        }

        rx_ring->head = head;

        return processed;
}

static void xge_delete_desc_ring(struct net_device *ndev,
                                 struct xge_desc_ring *ring)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct device *dev = &pdata->pdev->dev;
        u16 size;

        if (!ring)
                return;

        size = XGENE_ENET_DESC_SIZE * XGENE_ENET_NUM_DESC;
        if (ring->desc_addr)
                dma_free_coherent(dev, size, ring->desc_addr, ring->dma_addr);

        kfree(ring->pkt_info);
        kfree(ring);
}

static void xge_free_buffers(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct xge_desc_ring *ring = pdata->rx_ring;
        struct device *dev = &pdata->pdev->dev;
        struct sk_buff *skb;
        dma_addr_t dma_addr;
        int i;

        for (i = 0; i < XGENE_ENET_NUM_DESC; i++) {
                skb = ring->pkt_info[i].skb;
                dma_addr = ring->pkt_info[i].dma_addr;

                if (!skb)
                        continue;

                dma_unmap_single(dev, dma_addr, XGENE_ENET_STD_MTU,
                                 DMA_FROM_DEVICE);
                dev_kfree_skb_any(skb);
        }
}

static void xge_delete_desc_rings(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);

        xge_txc_poll(ndev);
        xge_delete_desc_ring(ndev, pdata->tx_ring);

        xge_rx_poll(ndev, 64);
        xge_free_buffers(ndev);
        xge_delete_desc_ring(ndev, pdata->rx_ring);
}

static struct xge_desc_ring *xge_create_desc_ring(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct device *dev = &pdata->pdev->dev;
        struct xge_desc_ring *ring;
        u16 size;

        ring = kzalloc_obj(*ring);
        if (!ring)
                return NULL;

        ring->ndev = ndev;

        size = XGENE_ENET_DESC_SIZE * XGENE_ENET_NUM_DESC;
        ring->desc_addr = dma_alloc_coherent(dev, size, &ring->dma_addr,
                                             GFP_KERNEL);
        if (!ring->desc_addr)
                goto err;

        ring->pkt_info = kzalloc_objs(*ring->pkt_info, XGENE_ENET_NUM_DESC);
        if (!ring->pkt_info)
                goto err;

        xge_setup_desc(ring);

        return ring;

err:
        xge_delete_desc_ring(ndev, ring);

        return NULL;
}

static int xge_create_desc_rings(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct xge_desc_ring *ring;
        int ret;

        /* create tx ring */
        ring = xge_create_desc_ring(ndev);
        if (!ring)
                goto err;

        pdata->tx_ring = ring;
        xge_update_tx_desc_addr(pdata);

        /* create rx ring */
        ring = xge_create_desc_ring(ndev);
        if (!ring)
                goto err;

        pdata->rx_ring = ring;
        xge_update_rx_desc_addr(pdata);

        ret = xge_refill_buffers(ndev, XGENE_ENET_NUM_DESC);
        if (ret)
                goto err;

        return 0;
err:
        xge_delete_desc_rings(ndev);

        return -ENOMEM;
}

static int xge_open(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        int ret;

        ret = xge_create_desc_rings(ndev);
        if (ret)
                return ret;

        napi_enable(&pdata->napi);
        ret = xge_request_irq(ndev);
        if (ret)
                return ret;

        xge_intr_enable(pdata);
        xge_wr_csr(pdata, DMARXCTRL, 1);

        phy_start(ndev->phydev);
        xge_mac_enable(pdata);
        netif_start_queue(ndev);

        return 0;
}

static int xge_close(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);

        netif_stop_queue(ndev);
        xge_mac_disable(pdata);
        phy_stop(ndev->phydev);

        xge_intr_disable(pdata);
        xge_free_irq(ndev);
        napi_disable(&pdata->napi);
        xge_delete_desc_rings(ndev);

        return 0;
}

static int xge_napi(struct napi_struct *napi, const int budget)
{
        struct net_device *ndev = napi->dev;
        struct xge_pdata *pdata;
        int processed;

        pdata = netdev_priv(ndev);

        xge_txc_poll(ndev);
        processed = xge_rx_poll(ndev, budget);

        if (processed < budget) {
                napi_complete_done(napi, processed);
                xge_intr_enable(pdata);
        }

        return processed;
}

static int xge_set_mac_addr(struct net_device *ndev, void *addr)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        int ret;

        ret = eth_mac_addr(ndev, addr);
        if (ret)
                return ret;

        xge_mac_set_station_addr(pdata);

        return 0;
}

static bool is_tx_pending(struct xge_raw_desc *raw_desc)
{
        if (!GET_BITS(E, le64_to_cpu(raw_desc->m0)))
                return true;

        return false;
}

static void xge_free_pending_skb(struct net_device *ndev)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct device *dev = &pdata->pdev->dev;
        struct xge_desc_ring *tx_ring;
        struct xge_raw_desc *raw_desc;
        dma_addr_t dma_addr;
        struct sk_buff *skb;
        void *pkt_buf;
        int i;

        tx_ring = pdata->tx_ring;

        for (i = 0; i < XGENE_ENET_NUM_DESC; i++) {
                raw_desc = &tx_ring->raw_desc[i];

                if (!is_tx_pending(raw_desc))
                        continue;

                skb = tx_ring->pkt_info[i].skb;
                dma_addr = tx_ring->pkt_info[i].dma_addr;
                pkt_buf = tx_ring->pkt_info[i].pkt_buf;
                dma_free_coherent(dev, XGENE_ENET_STD_MTU, pkt_buf, dma_addr);
                dev_kfree_skb_any(skb);
        }
}

static void xge_timeout(struct net_device *ndev, unsigned int txqueue)
{
        struct xge_pdata *pdata = netdev_priv(ndev);

        rtnl_lock();

        if (!netif_running(ndev))
                goto out;

        netif_stop_queue(ndev);
        xge_intr_disable(pdata);
        napi_disable(&pdata->napi);

        xge_wr_csr(pdata, DMATXCTRL, 0);
        xge_txc_poll(ndev);
        xge_free_pending_skb(ndev);
        xge_wr_csr(pdata, DMATXSTATUS, ~0U);

        xge_setup_desc(pdata->tx_ring);
        xge_update_tx_desc_addr(pdata);
        xge_mac_init(pdata);

        napi_enable(&pdata->napi);
        xge_intr_enable(pdata);
        xge_mac_enable(pdata);
        netif_start_queue(ndev);

out:
        rtnl_unlock();
}

static void xge_get_stats64(struct net_device *ndev,
                            struct rtnl_link_stats64 *storage)
{
        struct xge_pdata *pdata = netdev_priv(ndev);
        struct xge_stats *stats = &pdata->stats;

        storage->tx_packets += stats->tx_packets;
        storage->tx_bytes += stats->tx_bytes;

        storage->rx_packets += stats->rx_packets;
        storage->rx_bytes += stats->rx_bytes;
        storage->rx_errors += stats->rx_errors;
}

static const struct net_device_ops xgene_ndev_ops = {
        .ndo_open = xge_open,
        .ndo_stop = xge_close,
        .ndo_start_xmit = xge_start_xmit,
        .ndo_set_mac_address = xge_set_mac_addr,
        .ndo_tx_timeout = xge_timeout,
        .ndo_get_stats64 = xge_get_stats64,
};

static int xge_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct net_device *ndev;
        struct xge_pdata *pdata;
        int ret;

        ndev = alloc_etherdev(sizeof(*pdata));
        if (!ndev)
                return -ENOMEM;

        pdata = netdev_priv(ndev);

        pdata->pdev = pdev;
        pdata->ndev = ndev;
        SET_NETDEV_DEV(ndev, dev);
        platform_set_drvdata(pdev, pdata);
        ndev->netdev_ops = &xgene_ndev_ops;

        ndev->features |= NETIF_F_GSO |
                          NETIF_F_GRO;

        ret = xge_get_resources(pdata);
        if (ret)
                goto err;

        ndev->hw_features = ndev->features;
        xge_set_ethtool_ops(ndev);

        ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(64));
        if (ret) {
                netdev_err(ndev, "No usable DMA configuration\n");
                goto err;
        }

        ret = xge_init_hw(ndev);
        if (ret)
                goto err;

        ret = xge_mdio_config(ndev);
        if (ret)
                goto err;

        netif_napi_add(ndev, &pdata->napi, xge_napi);

        ret = register_netdev(ndev);
        if (ret) {
                netdev_err(ndev, "Failed to register netdev\n");
                goto err_mdio_remove;
        }

        return 0;

err_mdio_remove:
        xge_mdio_remove(ndev);
err:
        free_netdev(ndev);

        return ret;
}

static void xge_remove(struct platform_device *pdev)
{
        struct xge_pdata *pdata;
        struct net_device *ndev;

        pdata = platform_get_drvdata(pdev);
        ndev = pdata->ndev;

        rtnl_lock();
        if (netif_running(ndev))
                dev_close(ndev);
        rtnl_unlock();

        xge_mdio_remove(ndev);
        unregister_netdev(ndev);
        free_netdev(ndev);
}

static void xge_shutdown(struct platform_device *pdev)
{
        struct xge_pdata *pdata;

        pdata = platform_get_drvdata(pdev);
        if (!pdata)
                return;

        if (!pdata->ndev)
                return;

        xge_remove(pdev);
}

static const struct acpi_device_id xge_acpi_match[] = {
        { "APMC0D80" },
        { }
};
MODULE_DEVICE_TABLE(acpi, xge_acpi_match);

static struct platform_driver xge_driver = {
        .driver = {
                   .name = "xgene-enet-v2",
                   .acpi_match_table = xge_acpi_match,
        },
        .probe = xge_probe,
        .remove = xge_remove,
        .shutdown = xge_shutdown,
};
module_platform_driver(xge_driver);

MODULE_DESCRIPTION("APM X-Gene SoC Ethernet v2 driver");
MODULE_AUTHOR("Iyappan Subramanian <isubramanian@apm.com>");
MODULE_LICENSE("GPL");