Re: [PATCH net-next 2/3] net: dsa: vsc73xx: implement packet reception via control interface

From: Simon Horman
Date: Mon Oct 21 2024 - 06:48:11 EST


On Sun, Oct 20, 2024 at 10:54:51PM +0200, Pawel Dembicki wrote:
> Some types of packets can be forwarded only to and from the PI/SI
> interface. For more information, see Chapter 2.7.1 (CPU Forwarding) in
> the datasheet.
>
> This patch implements the routines required for link-local reception.
> This kind of traffic can't be transferred through the RGMII interface in
> vsc73xx.
>
> The packet receiver poller uses a kthread worker, which checks if a packet
> has arrived in the CPU buffer. If the header is valid, the packet is
> transferred to the correct DSA conduit interface.
>
> Signed-off-by: Pawel Dembicki <paweldembicki@xxxxxxxxx>

Hi Pawel,

This is not a full review, but I noticed a problem that I wanted to bring
to your attention. Please wait a day or so for others to provide a proper
review before posting a v2.

Thanks!

> ---
> drivers/net/dsa/vitesse-vsc73xx-core.c | 174 +++++++++++++++++++++++++
> drivers/net/dsa/vitesse-vsc73xx.h | 4 +
> 2 files changed, 178 insertions(+)
>
> diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c

...

> @@ -373,6 +415,7 @@
> #define VSC73XX_POLL_SLEEP_US 1000
> #define VSC73XX_MDIO_POLL_SLEEP_US 5
> #define VSC73XX_POLL_TIMEOUT_US 10000
> +#define VSC73XX_RCV_POLL_INTERVAL 100
>
> #define VSC73XX_IFH_MAGIC 0x52
> #define VSC73XX_IFH_SIZE 8
> @@ -834,6 +877,115 @@ static void vsc73xx_deferred_xmit(struct kthread_work *work)
> kfree(xmit_work);
> }
>
> +static void vsc73xx_polled_rcv(struct kthread_work *work)
> +{
> + struct vsc73xx *vsc = container_of(work, struct vsc73xx, dwork.work);
> + u16 ptr = VSC73XX_CAPT_FRAME_DATA;
> + struct dsa_switch *ds = vsc->ds;
> + int ret, buf_len, len, part;
> + struct vsc73xx_ifh ifh;
> + struct net_device *dev;
> + struct dsa_port *dp;
> + struct sk_buff *skb;
> + u32 val, *buf;
> + u16 count;
> +
> + ret = vsc73xx_read(vsc, VSC73XX_BLOCK_SYSTEM, 0, VSC73XX_CAPCTRL, &val);
> + if (ret)
> + goto queue;
> +
> + if (!(val & VSC73XX_CAPCTRL_QUEUE0_READY))
> + /* No frame to read */
> + goto queue;
> +
> + /* Initialise reading */
> + ret = vsc73xx_read(vsc, VSC73XX_BLOCK_CAPTURE, VSC73XX_BLOCK_CAPT_Q0,
> + VSC73XX_CAPT_CAPREADP, &val);
> + if (ret)
> + goto queue;
> +
> + /* Get internal frame header */
> + ret = vsc73xx_read(vsc, VSC73XX_BLOCK_CAPTURE,
> + VSC73XX_BLOCK_CAPT_FRAME0, ptr++, &ifh.datah);
> + if (ret)
> + goto queue;
> +
> + ret = vsc73xx_read(vsc, VSC73XX_BLOCK_CAPTURE,
> + VSC73XX_BLOCK_CAPT_FRAME0, ptr++, &ifh.datal);
> + if (ret)
> + goto queue;
> +
> + if (ifh.magic != VSC73XX_IFH_MAGIC) {
> + /* Something goes wrong with buffer. Reset capture block */
> + vsc73xx_write(vsc, VSC73XX_BLOCK_CAPTURE,
> + VSC73XX_BLOCK_CAPT_RST, VSC73XX_CAPT_CAPRST, 1);
> + goto queue;
> + }
> +
> + if (!dsa_is_user_port(ds, ifh.port))
> + goto release_frame;
> +
> + dp = dsa_to_port(ds, ifh.port);
> + dev = dp->user;
> + if (!dev)
> + goto release_frame;
> +
> + count = (ifh.frame_length + 7 + VSC73XX_IFH_SIZE - ETH_FCS_LEN) >> 2;
> +
> + skb = netdev_alloc_skb(dev, len);

len does not appear to be initialised here.

Flagged by W=1 builds.

> + if (unlikely(!skb)) {
> + netdev_err(dev, "Unable to allocate sk_buff\n");
> + goto release_frame;
> + }
> +
> + buf_len = ifh.frame_length - ETH_FCS_LEN;
> + buf = (u32 *)skb_put(skb, buf_len);
> + len = 0;
> + part = 0;
> +
> + while (ptr < count) {
> + ret = vsc73xx_read(vsc, VSC73XX_BLOCK_CAPTURE,
> + VSC73XX_BLOCK_CAPT_FRAME0 + part, ptr++,
> + buf + len);
> + if (ret)
> + goto free_skb;
> + len++;
> + if (ptr > VSC73XX_CAPT_FRAME_DATA_MAX &&
> + count != VSC73XX_CAPT_FRAME_DATA_MAX) {
> + ptr = VSC73XX_CAPT_FRAME_DATA;
> + part++;
> + count -= VSC73XX_CAPT_FRAME_DATA_MAX;
> + }
> + }
> +
> + /* Get FCS */
> + ret = vsc73xx_read(vsc, VSC73XX_BLOCK_CAPTURE,
> + VSC73XX_BLOCK_CAPT_FRAME0, ptr++, &val);
> + if (ret)
> + goto free_skb;
> +
> + /* Everything we see on an interface that is in the HW bridge
> + * has already been forwarded.
> + */
> + if (dp->bridge)
> + skb->offload_fwd_mark = 1;
> +
> + skb->protocol = eth_type_trans(skb, dev);
> +
> + netif_rx(skb);
> + goto release_frame;
> +
> +free_skb:
> + kfree_skb(skb);
> +release_frame:
> + /* Release the frame from internal buffer */
> + vsc73xx_write(vsc, VSC73XX_BLOCK_CAPTURE, VSC73XX_BLOCK_CAPT_Q0,
> + VSC73XX_CAPT_CAPREADP, 0);
> +queue:
> + kthread_queue_delayed_work(vsc->rcv_worker, &vsc->dwork,
> + msecs_to_jiffies(VSC73XX_RCV_POLL_INTERVAL));
> +}

...

--
pw-bot: changes-requested