Re: [PATCH v10 3/3] net: ax88796c: ASIX AX88796C SPI Ethernet Adapter Driver

From: Jakub Kicinski
Date: Fri Jan 15 2021 - 20:28:24 EST

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In reply to: Łukasz Stelmach: "[PATCH v10 3/3] net: ax88796c: ASIX AX88796C SPI Ethernet Adapter Driver"
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On Wed, 13 Jan 2021 19:40:28 +0100 Łukasz Stelmach wrote:
> ASIX AX88796[1] is a versatile ethernet adapter chip, that can be
> connected to a CPU with a 8/16-bit bus or with an SPI. This driver
> supports SPI connection.
>
> The driver has been ported from the vendor kernel for ARTIK5[2]
> boards. Several changes were made to adapt it to the current kernel
> which include:
>
> + updated DT configuration,
> + clock configuration moved to DT,
> + new timer, ethtool and gpio APIs,
> + dev_* instead of pr_* and custom printk() wrappers,
> + removed awkward vendor power managemtn.
> + introduced ethtool tunable to control SPI compression
>
> [1] https://www.asix.com.tw/products.php?op=pItemdetail&PItemID=104;65;86&PLine=65
> [2] https://git.tizen.org/cgit/profile/common/platform/kernel/linux-3.10-artik/
>
> The other ax88796 driver is for NE2000 compatible AX88796L chip. These
> chips are not compatible. Hence, two separate drivers are required.
>
> Signed-off-by: Łukasz Stelmach <l.stelmach@xxxxxxxxxxx>
> Reviewed-by: Andrew Lunn <andrew@xxxxxxx>

> +static u32 ax88796c_get_priv_flags(struct net_device *ndev)
> +{
> + struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
> +
> + return ax_local->priv_flags;

stray indent

> +}

> +#define MAX(x,y) ((x) > (y) ? (x) : (y))

Please use the standard linux max / max_t macros.

> +static struct sk_buff *
> +ax88796c_tx_fixup(struct net_device *ndev, struct sk_buff_head *q)
> +{
> + struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
> + u8 spi_len = ax_local->ax_spi.comp ? 1 : 4;
> + struct sk_buff *skb;
> + struct tx_pkt_info *info;
> + struct skb_data *entry;
> + u16 pkt_len;
> + u8 padlen, seq_num;
> + u8 need_pages;
> + int headroom;
> + int tailroom;
> +
> + if (skb_queue_empty(q))
> + return NULL;
> +
> + skb = skb_peek(q);
> + pkt_len = skb->len;
> + need_pages = (pkt_len + TX_OVERHEAD + 127) >> 7;
> + if (ax88796c_check_free_pages(ax_local, need_pages) != 0)
> + return NULL;
> +
> + headroom = skb_headroom(skb);
> + tailroom = skb_tailroom(skb);
> + padlen = round_up(pkt_len, 4) - pkt_len;
> + seq_num = ++ax_local->seq_num & 0x1F;
> +
> + info = (struct tx_pkt_info *)skb->cb;
> + info->pkt_len = pkt_len;
> +
> + if (skb_cloned(skb) ||
> + (headroom < (TX_OVERHEAD + spi_len)) ||
> + (tailroom < (padlen + TX_EOP_SIZE))) {
> + size_t h = MAX((TX_OVERHEAD + spi_len) - headroom,0);
> + size_t t = MAX((padlen + TX_EOP_SIZE) - tailroom,0);
> +
> + if (pskb_expand_head(skb, h, t, GFP_KERNEL))
> + return NULL;
> + }
> +
> + info->seq_num = seq_num;
> + ax88796c_proc_tx_hdr(info, skb->ip_summed);
> +
> + /* SOP and SEG header */
> + memcpy(skb_push(skb, TX_OVERHEAD), &info->sop, TX_OVERHEAD);

why use skb->cb to store info? why not declare it on the stack?

> + /* Write SPI TXQ header */
> + memcpy(skb_push(skb, spi_len), ax88796c_tx_cmd_buf, spi_len);
> +
> + /* Make 32-bit alignment */
> + skb_put(skb, padlen);
> +
> + /* EOP header */
> + memcpy(skb_put(skb, TX_EOP_SIZE), &info->eop, TX_EOP_SIZE);
> +
> + skb_unlink(skb, q);
> +
> + entry = (struct skb_data *)skb->cb;
> + memset(entry, 0, sizeof(*entry));
> + entry->len = pkt_len;
> +
> + if (netif_msg_pktdata(ax_local)) {
> + char pfx[IFNAMSIZ + 7];
> +
> + snprintf(pfx, sizeof(pfx), "%s: ", ndev->name);
> +
> + netdev_info(ndev, "TX packet len %d, total len %d, seq %d\n",
> + pkt_len, skb->len, seq_num);
> +
> + netdev_info(ndev, " SPI Header:\n");
> + print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
> + skb->data, 4, 0);
> +
> + netdev_info(ndev, " TX SOP:\n");
> + print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
> + skb->data + 4, TX_OVERHEAD, 0);
> +
> + netdev_info(ndev, " TX packet:\n");
> + print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
> + skb->data + 4 + TX_OVERHEAD,
> + skb->len - TX_EOP_SIZE - 4 - TX_OVERHEAD, 0);
> +
> + netdev_info(ndev, " TX EOP:\n");
> + print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
> + skb->data + skb->len - 4, 4, 0);
> + }
> +
> + return skb;
> +}
> +
> +static int ax88796c_hard_xmit(struct ax88796c_device *ax_local)
> +{
> + struct sk_buff *tx_skb;
> + struct skb_data *entry;
> +
> + WARN_ON(!mutex_is_locked(&ax_local->spi_lock));
> +
> + tx_skb = ax88796c_tx_fixup(ax_local->ndev, &ax_local->tx_wait_q);
> +
> + if (!tx_skb)
> + return 0;

tx_dropped++ ?

> + entry = (struct skb_data *)tx_skb->cb;
> +
> + AX_WRITE(&ax_local->ax_spi,
> + (TSNR_TXB_START | TSNR_PKT_CNT(1)), P0_TSNR);
> +
> + axspi_write_txq(&ax_local->ax_spi, tx_skb->data, tx_skb->len);
> +
> + if (((AX_READ(&ax_local->ax_spi, P0_TSNR) & TXNR_TXB_IDLE) == 0) ||
> + ((ISR_TXERR & AX_READ(&ax_local->ax_spi, P0_ISR)) != 0)) {
> + /* Ack tx error int */
> + AX_WRITE(&ax_local->ax_spi, ISR_TXERR, P0_ISR);
> +
> + ax_local->stats.tx_dropped++;
> +
> + netif_err(ax_local, tx_err, ax_local->ndev,
> + "TX FIFO error, re-initialize the TX bridge\n");

rate limit

> + /* Reinitial tx bridge */
> + AX_WRITE(&ax_local->ax_spi, TXNR_TXB_REINIT |
> + AX_READ(&ax_local->ax_spi, P0_TSNR), P0_TSNR);
> + ax_local->seq_num = 0;
> + } else {
> + ax_local->stats.tx_packets++;
> + ax_local->stats.tx_bytes += entry->len;
> + }
> +
> + entry->state = tx_done;
> + dev_kfree_skb(tx_skb);

dev_consume_skb() is better in cases the xmission was correct.
kfree_skb() shows up in packet drop monitor.

> +
> + return 1;
> +}

> +static void
> +ax88796c_skb_return(struct ax88796c_device *ax_local, struct sk_buff *skb,
> + struct rx_header *rxhdr)
> +{
> + struct net_device *ndev = ax_local->ndev;
> + int status;
> +
> + do {
> + if (!(ndev->features & NETIF_F_RXCSUM))
> + break;
> +
> + /* checksum error bit is set */
> + if ((rxhdr->flags & RX_HDR3_L3_ERR) ||
> + (rxhdr->flags & RX_HDR3_L4_ERR))
> + break;
> +
> + /* Other types may be indicated by more than one bit. */
> + if ((rxhdr->flags & RX_HDR3_L4_TYPE_TCP) ||
> + (rxhdr->flags & RX_HDR3_L4_TYPE_UDP))
> + skb->ip_summed = CHECKSUM_UNNECESSARY;
> + } while (0);
> +
> + ax_local->stats.rx_packets++;
> + ax_local->stats.rx_bytes += skb->len;
> + skb->dev = ndev;
> +
> + skb->protocol = eth_type_trans(skb, ax_local->ndev);
> +
> + netif_info(ax_local, rx_status, ndev, "< rx, len %zu, type 0x%x\n",
> + skb->len + sizeof(struct ethhdr), skb->protocol);
> +
> + status = netif_rx_ni(skb);
> + if (status != NET_RX_SUCCESS)
> + netif_info(ax_local, rx_err, ndev,
> + "netif_rx status %d\n", status);

rate limit

> +}
> +
> +static void
> +ax88796c_rx_fixup(struct ax88796c_device *ax_local, struct sk_buff *rx_skb)
> +{
> + struct rx_header *rxhdr = (struct rx_header *)rx_skb->data;
> + struct net_device *ndev = ax_local->ndev;
> + u16 len;
> +
> + be16_to_cpus(&rxhdr->flags_len);
> + be16_to_cpus(&rxhdr->seq_lenbar);
> + be16_to_cpus(&rxhdr->flags);
> +
> + if (((rxhdr->flags_len) & RX_HDR1_PKT_LEN) !=
> + (~(rxhdr->seq_lenbar) & 0x7FF)) {

Lots of unnecessary parenthesis.

> + netif_err(ax_local, rx_err, ndev, "Header error\n");
> +
> + ax_local->stats.rx_frame_errors++;
> + kfree_skb(rx_skb);
> + return;
> + }
> +
> + if ((rxhdr->flags_len & RX_HDR1_MII_ERR) ||
> + (rxhdr->flags_len & RX_HDR1_CRC_ERR)) {
> + netif_err(ax_local, rx_err, ndev, "CRC or MII error\n");
> +
> + ax_local->stats.rx_crc_errors++;
> + kfree_skb(rx_skb);
> + return;
> + }
> +
> + len = rxhdr->flags_len & RX_HDR1_PKT_LEN;
> + if (netif_msg_pktdata(ax_local)) {
> + char pfx[IFNAMSIZ + 7];
> +
> + snprintf(pfx, sizeof(pfx), "%s: ", ndev->name);
> + netdev_info(ndev, "RX data, total len %d, packet len %d\n",
> + rx_skb->len, len);
> +
> + netdev_info(ndev, " Dump RX packet header:");
> + print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
> + rx_skb->data, sizeof(*rxhdr), 0);
> +
> + netdev_info(ndev, " Dump RX packet:");
> + print_hex_dump(KERN_INFO, pfx, DUMP_PREFIX_OFFSET, 16, 1,
> + rx_skb->data + sizeof(*rxhdr), len, 0);
> + }
> +
> + skb_pull(rx_skb, sizeof(*rxhdr));
> + pskb_trim(rx_skb, len);
> +
> + ax88796c_skb_return(ax_local, rx_skb, rxhdr);
> +}
> +
> +static int ax88796c_receive(struct net_device *ndev)
> +{
> + struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
> + struct skb_data *entry;
> + u16 w_count, pkt_len;
> + struct sk_buff *skb;
> + u8 pkt_cnt;
> +
> + WARN_ON(!mutex_is_locked(&ax_local->spi_lock));
> +
> + /* check rx packet and total word count */
> + AX_WRITE(&ax_local->ax_spi, AX_READ(&ax_local->ax_spi, P0_RTWCR)
> + | RTWCR_RX_LATCH, P0_RTWCR);
> +
> + pkt_cnt = AX_READ(&ax_local->ax_spi, P0_RXBCR2) & RXBCR2_PKT_MASK;
> + if (!pkt_cnt)
> + return 0;
> +
> + pkt_len = AX_READ(&ax_local->ax_spi, P0_RCPHR) & 0x7FF;
> +
> + w_count = ((pkt_len + 6 + 3) & 0xFFFC) >> 1;

w_count = round_up(pkt_len + 6, 4) >> 1;

> + skb = netdev_alloc_skb(ndev, (w_count * 2));

parenthesis unnecessary

> + if (!skb) {
> + AX_WRITE(&ax_local->ax_spi, RXBCR1_RXB_DISCARD, P0_RXBCR1);

Increment rx_dropped counter here?

> + return 0;
> + }
> + entry = (struct skb_data *)skb->cb;
> +
> + AX_WRITE(&ax_local->ax_spi, RXBCR1_RXB_START | w_count, P0_RXBCR1);
> +
> + axspi_read_rxq(&ax_local->ax_spi,
> + skb_put(skb, w_count * 2), skb->len);
> +
> + /* Check if rx bridge is idle */
> + if ((AX_READ(&ax_local->ax_spi, P0_RXBCR2) & RXBCR2_RXB_IDLE) == 0) {
> + netif_err(ax_local, rx_err, ndev,
> + "Rx Bridge is not idle\n");

rate limit?

> + AX_WRITE(&ax_local->ax_spi, RXBCR2_RXB_REINIT, P0_RXBCR2);
> +
> + entry->state = rx_err;
> + } else {
> + entry->state = rx_done;
> + }
> +
> + AX_WRITE(&ax_local->ax_spi, ISR_RXPKT, P0_ISR);
> +
> + ax88796c_rx_fixup(ax_local, skb);
> +
> + return 1;
> +}
> +
> +static int ax88796c_process_isr(struct ax88796c_device *ax_local)
> +{
> + struct net_device *ndev = ax_local->ndev;
> + u8 done = 0;

The logic associated with this variable is "is there more to do" rather
than "done", no?

> + u16 isr;
> +
> + WARN_ON(!mutex_is_locked(&ax_local->spi_lock));
> +
> + isr = AX_READ(&ax_local->ax_spi, P0_ISR);
> + AX_WRITE(&ax_local->ax_spi, isr, P0_ISR);
> +
> + netif_dbg(ax_local, intr, ndev, " ISR 0x%04x\n", isr);
> +
> + if (isr & ISR_TXERR) {
> + netif_dbg(ax_local, intr, ndev, " TXERR interrupt\n");
> + AX_WRITE(&ax_local->ax_spi, TXNR_TXB_REINIT, P0_TSNR);
> + ax_local->seq_num = 0x1f;
> + }
> +
> + if (isr & ISR_TXPAGES) {
> + netif_dbg(ax_local, intr, ndev, " TXPAGES interrupt\n");
> + set_bit(EVENT_TX, &ax_local->flags);
> + }
> +
> + if (isr & ISR_LINK) {
> + netif_dbg(ax_local, intr, ndev, " Link change interrupt\n");
> + phy_mac_interrupt(ax_local->ndev->phydev);
> + }
> +
> + if (isr & ISR_RXPKT) {
> + netif_dbg(ax_local, intr, ndev, " RX interrupt\n");
> + done = ax88796c_receive(ax_local->ndev);
> + }
> +
> + return done;
> +}

> +static void ax88796c_work(struct work_struct *work)
> +{
> + struct ax88796c_device *ax_local =
> + container_of(work, struct ax88796c_device, ax_work);
> +
> + mutex_lock(&ax_local->spi_lock);
> +
> + if (test_bit(EVENT_SET_MULTI, &ax_local->flags)) {
> + ax88796c_set_hw_multicast(ax_local->ndev);
> + clear_bit(EVENT_SET_MULTI, &ax_local->flags);
> + }
> +
> + if (test_bit(EVENT_INTR, &ax_local->flags)) {
> + AX_WRITE(&ax_local->ax_spi, IMR_MASKALL, P0_IMR);
> +
> + while (1) {
> + if (!ax88796c_process_isr(ax_local))
> + break;

while (ax88796c_process_isr(ax_local))
/* nothing */;
?

> + }
> +
> + clear_bit(EVENT_INTR, &ax_local->flags);
> +
> + AX_WRITE(&ax_local->ax_spi, IMR_DEFAULT, P0_IMR);
> +
> + enable_irq(ax_local->ndev->irq);
> + }
> +
> + if (test_bit(EVENT_TX, &ax_local->flags)) {
> + while (skb_queue_len(&ax_local->tx_wait_q)) {
> + if (!ax88796c_hard_xmit(ax_local))
> + break;
> + }
> +
> + clear_bit(EVENT_TX, &ax_local->flags);
> +
> + if (netif_queue_stopped(ax_local->ndev) &&
> + (skb_queue_len(&ax_local->tx_wait_q) < TX_QUEUE_LOW_WATER))
> + netif_wake_queue(ax_local->ndev);
> + }
> +
> + mutex_unlock(&ax_local->spi_lock);
> +}

> +static void ax88796c_set_csums(struct ax88796c_device *ax_local)
> +{
> + struct net_device *ndev = ax_local->ndev;
> +
> + WARN_ON(!mutex_is_locked(&ax_local->spi_lock));

lockdep_assert_held() in all those cases

> +static void ax88796c_free_skb_queue(struct sk_buff_head *q)
> +{
> + struct sk_buff *skb;
> +
> + while (q->qlen) {
> + skb = skb_dequeue(q);
> + kfree_skb(skb);
> + }

__skb_queue_purge()

> +}
> +
> +static int
> +ax88796c_close(struct net_device *ndev)
> +{
> + struct ax88796c_device *ax_local = to_ax88796c_device(ndev);
> +
> + netif_stop_queue(ndev);
> + phy_stop(ndev->phydev);
> +
> + mutex_lock(&ax_local->spi_lock);
> +
> + /* Disable MAC interrupts */
> + AX_WRITE(&ax_local->ax_spi, IMR_MASKALL, P0_IMR);
> + ax88796c_free_skb_queue(&ax_local->tx_wait_q);
> + ax88796c_soft_reset(ax_local);
> +
> + mutex_unlock(&ax_local->spi_lock);
> +
> + free_irq(ndev->irq, ndev);
> +
> + return 0;
> +}

> +struct ax88796c_device {
> + struct spi_device *spi;
> + struct net_device *ndev;
> + struct net_device_stats stats;

You need to use 64 bit stats, like struct rtnl_link_stats64.
On a 32bit system at 100Mbps ulong can wrap in minutes.

> + struct work_struct ax_work;

I don't see you ever canceling / flushing this work.
You should do that at least on driver remove if not close.

> + struct mutex spi_lock; /* device access */
> +
> + struct sk_buff_head tx_wait_q;
> +
> + struct axspi_data ax_spi;
> +
> + struct mii_bus *mdiobus;
> + struct phy_device *phydev;
> +
> + int msg_enable;
> +
> + u16 seq_num;
> +
> + u8 multi_filter[AX_MCAST_FILTER_SIZE];
> +
> + int link;
> + int speed;
> + int duplex;
> + int pause;
> + int asym_pause;
> + int flowctrl;
> + #define AX_FC_NONE 0
> + #define AX_FC_RX BIT(0)
> + #define AX_FC_TX BIT(1)
> + #define AX_FC_ANEG BIT(2)
> +
> + u32 priv_flags;
> + #define AX_CAP_COMP BIT(0)
> + #define AX_PRIV_FLAGS_MASK (AX_CAP_COMP)
> +
> + unsigned long flags;
> + #define EVENT_INTR BIT(0)
> + #define EVENT_TX BIT(1)
> + #define EVENT_SET_MULTI BIT(2)
> +
> +};

> +struct skb_data {
> + enum skb_state state;
> + struct net_device *ndev;
> + struct sk_buff *skb;

Don't think you ever use the skb or ndev from this structure.

> + size_t len;
> +};

Next message: Miguel Ojeda: "Re: [PATCH v2] kbuild: check the minimum compiler version in Kconfig"
Previous message: Dario Faggioli: "Re: [PATCH] kvm: tracing: Fix unmatched kvm_entry and kvm_exit events"
In reply to: Łukasz Stelmach: "[PATCH v10 3/3] net: ax88796c: ASIX AX88796C SPI Ethernet Adapter Driver"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]