diff mbox series

[RFC,net-next,12/28] net: ethernet: ti: cpsw-proxy-client: add NAPI RX polling function

Message ID 20240518124234.2671651-13-s-vadapalli@ti.com (mailing list archive)
State RFC
Delegated to: Netdev Maintainers
Headers show
Series Add CPSW Proxy Client driver | expand

Checks

Context Check Description
netdev/series_format fail Series longer than 15 patches
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 24 this patch: 24
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: linux-omap@vger.kernel.org
netdev/build_clang success Errors and warnings before: 8 this patch: 8
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 23 this patch: 23
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 220 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Siddharth Vadapalli May 18, 2024, 12:42 p.m. UTC
Add the "vport_rx_poll()" function to be registered as the NAPI RX
polling function via "netif_napi_add()".

Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
---
 drivers/net/ethernet/ti/cpsw-proxy-client.c | 189 ++++++++++++++++++++
 1 file changed, 189 insertions(+)

Comments

Markus Elfring May 19, 2024, 1:18 p.m. UTC | #1
> +++ b/drivers/net/ethernet/ti/cpsw-proxy-client.c> @@ -988,6 +994,189 @@ static int vport_tx_poll(struct napi_struct *napi_tx, int budget)> +static int vport_rx_packets(struct virtual_port *vport, u32 rx_chan_idx)
> +{> +	if (unlikely(!netif_running(skb->dev))) {
> +		dev_kfree_skb_any(skb);
> +		return -ENODEV;
> +	}

I suggest to move such exception handling to the end of this function implementation
so that it can be better reused also by another if branch.
https://wiki.sei.cmu.edu/confluence/display/c/MEM12-C.+Consider+using+a+goto+chain+when+leaving+a+function+on+error+when+using+and+releasing+resources

How do you think about to increase the application of scope-based resource management
also for such a software component?
https://elixir.bootlin.com/linux/v6.9.1/source/include/linux/cleanup.h

Regards,
Markus
Matthew Wilcox May 19, 2024, 2 p.m. UTC | #2
FYI, Markus can be safely ignored.  His opinions are well-established as
being irrelevant.

On Sun, May 19, 2024 at 03:18:52PM +0200, Markus Elfring wrote:
> …
> > +++ b/drivers/net/ethernet/ti/cpsw-proxy-client.c
> …
> > @@ -988,6 +994,189 @@ static int vport_tx_poll(struct napi_struct *napi_tx, int budget)
> …
> > +static int vport_rx_packets(struct virtual_port *vport, u32 rx_chan_idx)
> > +{
> …
> > +	if (unlikely(!netif_running(skb->dev))) {
> > +		dev_kfree_skb_any(skb);
> > +		return -ENODEV;
> > +	}
> 
> I suggest to move such exception handling to the end of this function implementation
> so that it can be better reused also by another if branch.
> https://wiki.sei.cmu.edu/confluence/display/c/MEM12-C.+Consider+using+a+goto+chain+when+leaving+a+function+on+error+when+using+and+releasing+resources
> 
> How do you think about to increase the application of scope-based resource management
> also for such a software component?
> https://elixir.bootlin.com/linux/v6.9.1/source/include/linux/cleanup.h
> 
> Regards,
> Markus
>
Markus Elfring May 19, 2024, 2:30 p.m. UTC | #3
> FYI, Markus can be safely ignored.  His opinions are well-established as
> being irrelevant.

I hope that views can become more constructive somehow.


…
>> https://wiki.sei.cmu.edu/confluence/display/c/MEM12-C.+Consider+using+a+goto+chain+when+leaving+a+function+on+error+when+using+and+releasing+resources>> https://elixir.bootlin.com/linux/v6.9.1/source/include/linux/cleanup.h

Do linked information sources provide more helpful clarification opportunities
also for undesirable communication difficulties?

Regards,
Markus
Andrew Lunn May 19, 2024, 3:37 p.m. UTC | #4
On Sun, May 19, 2024 at 03:00:42PM +0100, Matthew Wilcox wrote:
> 
> FYI, Markus can be safely ignored.  His opinions are well-established as
> being irrelevant.

I personally would suggest ignoring the nit-gritty details for the
moment, and concentrate on the big picture architecture. I suspect the
basic architecture is wrong, and the code is going to change in big
ways. So it is pointless reviewing the code at the moment, other than
to understand the architecture.

	Andrew
diff mbox series

Patch

diff --git a/drivers/net/ethernet/ti/cpsw-proxy-client.c b/drivers/net/ethernet/ti/cpsw-proxy-client.c
index cf99d8b6c1ec..6926f65a4613 100644
--- a/drivers/net/ethernet/ti/cpsw-proxy-client.c
+++ b/drivers/net/ethernet/ti/cpsw-proxy-client.c
@@ -6,7 +6,9 @@ 
  */
 
 #include <linux/etherdevice.h>
+#include <linux/if_vlan.h>
 #include <linux/kernel.h>
+#include <linux/kmemleak.h>
 #include <linux/module.h>
 #include <linux/rpmsg.h>
 #include <linux/dma/k3-udma-glue.h>
@@ -23,6 +25,8 @@ 
 #define MAX_RX_DESC	500
 #define MAX_RX_FLOWS	1
 
+#define MAX_PACKET_SIZE	(VLAN_ETH_FRAME_LEN + ETH_FCS_LEN)
+
 #define CHAN_NAME_LEN	128
 
 enum virtual_port_type {
@@ -51,6 +55,7 @@  struct rx_dma_chan {
 	struct device			*dev;
 	struct k3_cppi_desc_pool	*desc_pool;
 	struct k3_udma_glue_rx_channel	*rx_chan;
+	struct napi_struct		napi_rx;
 	u32				rel_chan_idx;
 	u32				flow_base;
 	u32				flow_offset;
@@ -90,6 +95,7 @@  struct vport_netdev_priv {
 
 struct virtual_port {
 	struct cpsw_proxy_priv		*proxy_priv;
+	struct net_device		*ndev;
 	struct rx_dma_chan		*rx_chans;
 	struct tx_dma_chan		*tx_chans;
 	struct completion		tdown_complete;
@@ -988,6 +994,189 @@  static int vport_tx_poll(struct napi_struct *napi_tx, int budget)
 	return 0;
 }
 
+/* RX psdata[2] word format - checksum information */
+#define RX_PSD_CSUM_ERR		BIT(16)
+#define RX_PSD_IS_FRAGMENT	BIT(17)
+#define RX_PSD_IPV6_VALID	BIT(19)
+#define RX_PSD_IPV4_VALID	BIT(20)
+
+static void vport_rx_csum(struct sk_buff *skb, u32 csum_info)
+{
+	/* HW can verify IPv4/IPv6 TCP/UDP packets checksum
+	 * csum information provides in psdata[2] word:
+	 * RX_PSD_CSUM_ERR bit - indicates csum error
+	 * RX_PSD_IPV6_VALID and CPSW_RX_PSD_IPV4_VALID
+	 * bits - indicates IPv4/IPv6 packet
+	 * RX_PSD_IS_FRAGMENT bit - indicates fragmented packet
+	 * RX_PSD_CSUM_ADD has value 0xFFFF for non fragmented packets
+	 * or csum value for fragmented packets if !RX_PSD_CSUM_ERR
+	 */
+	skb_checksum_none_assert(skb);
+
+	if (unlikely(!(skb->dev->features & NETIF_F_RXCSUM)))
+		return;
+
+	if ((csum_info & (RX_PSD_IPV6_VALID |
+			  RX_PSD_IPV4_VALID)) &&
+			  !(csum_info & RX_PSD_CSUM_ERR)) {
+		/* csum for fragmented packets is unsupported */
+		if (!(csum_info & RX_PSD_IS_FRAGMENT))
+			skb->ip_summed = CHECKSUM_UNNECESSARY;
+	}
+}
+
+static int vport_rx_push(struct virtual_port *vport, struct sk_buff *skb,
+			 u32 rx_chan_idx)
+{
+	struct rx_dma_chan *rx_chn = &vport->rx_chans[rx_chan_idx];
+	struct cpsw_proxy_priv *proxy_priv = vport->proxy_priv;
+	struct device *dev = proxy_priv->dev;
+	struct cppi5_host_desc_t *desc_rx;
+	u32 pkt_len = skb_tailroom(skb);
+	dma_addr_t desc_dma;
+	dma_addr_t buf_dma;
+	void *swdata;
+
+	desc_rx = k3_cppi_desc_pool_alloc(rx_chn->desc_pool);
+	if (!desc_rx) {
+		dev_err(dev, "Failed to allocate RXFDQ descriptor\n");
+		return -ENOMEM;
+	}
+	desc_dma = k3_cppi_desc_pool_virt2dma(rx_chn->desc_pool, desc_rx);
+
+	buf_dma = dma_map_single(dev, skb->data, pkt_len, DMA_FROM_DEVICE);
+	if (unlikely(dma_mapping_error(dev, buf_dma))) {
+		k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx);
+		dev_err(dev, "Failed to map rx skb buffer\n");
+		return -EINVAL;
+	}
+
+	cppi5_hdesc_init(desc_rx, CPPI5_INFO0_HDESC_EPIB_PRESENT,
+			 PS_DATA_SIZE);
+	cppi5_hdesc_attach_buf(desc_rx, 0, 0, buf_dma, skb_tailroom(skb));
+	swdata = cppi5_hdesc_get_swdata(desc_rx);
+	*((void **)swdata) = skb;
+
+	return k3_udma_glue_push_rx_chn(rx_chn->rx_chan, 0, desc_rx, desc_dma);
+}
+
+static int vport_rx_packets(struct virtual_port *vport, u32 rx_chan_idx)
+{
+	struct rx_dma_chan *rx_chn = &vport->rx_chans[rx_chan_idx];
+	struct cpsw_proxy_priv *proxy_priv = vport->proxy_priv;
+	u32 buf_dma_len, pkt_len, port_id = 0, csum_info;
+	struct device *dev = proxy_priv->dev;
+	struct vport_netdev_priv *ndev_priv;
+	struct cppi5_host_desc_t *desc_rx;
+	struct vport_netdev_stats *stats;
+	struct sk_buff *skb, *new_skb;
+	dma_addr_t desc_dma, buf_dma;
+	struct net_device *ndev;
+	u32 flow_idx = 0;
+	void **swdata;
+	int ret = 0;
+	u32 *psdata;
+
+	ret = k3_udma_glue_pop_rx_chn(rx_chn->rx_chan, flow_idx, &desc_dma);
+	if (ret) {
+		if (ret != -ENODATA)
+			dev_err(dev, "RX: pop chn fail %d\n", ret);
+		return ret;
+	}
+
+	if (desc_dma & 0x1) {
+		dev_dbg(dev, "%s RX tdown flow: %u\n", __func__, flow_idx);
+		return 0;
+	}
+
+	desc_rx = k3_cppi_desc_pool_dma2virt(rx_chn->desc_pool, desc_dma);
+	dev_dbg(dev, "%s flow_idx: %u desc %pad\n",
+		__func__, flow_idx, &desc_dma);
+
+	swdata = cppi5_hdesc_get_swdata(desc_rx);
+	skb = *swdata;
+	cppi5_hdesc_get_obuf(desc_rx, &buf_dma, &buf_dma_len);
+	pkt_len = cppi5_hdesc_get_pktlen(desc_rx);
+	cppi5_desc_get_tags_ids(&desc_rx->hdr, &port_id, NULL);
+	/* read port for dbg */
+	dev_dbg(dev, "%s rx port_id:%d\n", __func__, port_id);
+	ndev = vport->ndev;
+	skb->dev = ndev;
+
+	psdata = cppi5_hdesc_get_psdata(desc_rx);
+	csum_info = psdata[2];
+	dev_dbg(dev, "%s rx csum_info:%#x\n", __func__, csum_info);
+
+	dma_unmap_single(dev, buf_dma, buf_dma_len, DMA_FROM_DEVICE);
+
+	k3_cppi_desc_pool_free(rx_chn->desc_pool, desc_rx);
+
+	if (unlikely(!netif_running(skb->dev))) {
+		dev_kfree_skb_any(skb);
+		return -ENODEV;
+	}
+
+	new_skb = netdev_alloc_skb_ip_align(ndev, MAX_PACKET_SIZE);
+	if (new_skb) {
+		skb_put(skb, pkt_len);
+		skb->protocol = eth_type_trans(skb, ndev);
+		vport_rx_csum(skb, csum_info);
+		napi_gro_receive(&rx_chn->napi_rx, skb);
+
+		ndev_priv = netdev_priv(ndev);
+		stats = this_cpu_ptr(ndev_priv->stats);
+
+		u64_stats_update_begin(&stats->syncp);
+		stats->rx_packets++;
+		stats->rx_bytes += pkt_len;
+		u64_stats_update_end(&stats->syncp);
+		kmemleak_not_leak(new_skb);
+	} else {
+		ndev->stats.rx_dropped++;
+		new_skb = skb;
+	}
+
+	if (netif_dormant(ndev)) {
+		dev_kfree_skb_any(new_skb);
+		ndev->stats.rx_dropped++;
+		return -ENODEV;
+	}
+
+	ret = vport_rx_push(vport, new_skb, rx_chn->rel_chan_idx);
+	if (WARN_ON(ret < 0)) {
+		dev_kfree_skb_any(new_skb);
+		ndev->stats.rx_errors++;
+		ndev->stats.rx_dropped++;
+	}
+
+	return ret;
+}
+
+static int vport_rx_poll(struct napi_struct *napi_rx, int budget)
+{
+	struct rx_dma_chan *rx_chn = container_of(napi_rx, struct rx_dma_chan,
+							 napi_rx);
+	struct virtual_port *vport = rx_chn->vport;
+	int num_rx = 0;
+	int cur_budget;
+	int ret;
+
+	/* process every flow */
+	cur_budget = budget;
+
+	while (cur_budget--) {
+		ret = vport_rx_packets(vport, rx_chn->rel_chan_idx);
+		if (ret)
+			break;
+		num_rx++;
+	}
+
+	if (num_rx < budget && napi_complete_done(napi_rx, num_rx))
+		enable_irq(rx_chn->irq);
+
+	return num_rx;
+}
+
 static int cpsw_proxy_client_probe(struct rpmsg_device *rpdev)
 {
 	struct cpsw_proxy_priv *proxy_priv;