Re: [PATCH net-next 3/3] net: ethernet: ti: cpsw: add XDP support
From: Ivan Khoronzhuk
Date: Mon May 27 2019 - 14:32:48 EST
On Fri, May 24, 2019 at 08:49:38PM +0300, grygorii wrote:
Hi Ivan,
On 23/05/2019 21:20, Ivan Khoronzhuk wrote:
Add XDP support based on rx page_pool allocator, one frame per page.
Page pool allocator is used with assumption that only one rx_handler
is running simultaneously. DMA map/unmap is reused from page pool
despite there is no need to map whole page.
Due to specific of cpsw, the same TX/RX handler can be used by 2
network devices, so special fields in buffer are added to identify
an interface the frame is destined to. Thus XDP works for both
interfaces, that allows to test xdp redirect between two interfaces
easily.
XDP prog is common for all channels till appropriate changes are added
in XDP infrastructure.
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
---
drivers/net/ethernet/ti/Kconfig | 1 +
drivers/net/ethernet/ti/cpsw.c | 555 ++++++++++++++++++++++---
drivers/net/ethernet/ti/cpsw_ethtool.c | 53 +++
drivers/net/ethernet/ti/cpsw_priv.h | 7 +
4 files changed, 554 insertions(+), 62 deletions(-)
diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig
index bd05a977ee7e..3cb8c5214835 100644
--- a/drivers/net/ethernet/ti/Kconfig
+++ b/drivers/net/ethernet/ti/Kconfig
@@ -50,6 +50,7 @@ config TI_CPSW
depends on ARCH_DAVINCI || ARCH_OMAP2PLUS || COMPILE_TEST
select TI_DAVINCI_MDIO
select MFD_SYSCON
+ select PAGE_POOL
select REGMAP
---help---
This driver supports TI's CPSW Ethernet Switch.
diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index 87a600aeee4a..274e6b64ea9e 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -31,6 +31,10 @@
#include <linux/if_vlan.h>
#include <linux/kmemleak.h>
#include <linux/sys_soc.h>
+#include <net/page_pool.h>
+#include <linux/bpf.h>
+#include <linux/bpf_trace.h>
+#include <linux/filter.h>
#include <linux/pinctrl/consumer.h>
#include <net/pkt_cls.h>
@@ -60,6 +64,10 @@ static int descs_pool_size = CPSW_CPDMA_DESCS_POOL_SIZE_DEFAULT;
module_param(descs_pool_size, int, 0444);
MODULE_PARM_DESC(descs_pool_size, "Number of CPDMA CPPI descriptors in pool");
+/* The buf includes headroom compatible with both skb and xdpf */
+#define CPSW_HEADROOM_NA (max(XDP_PACKET_HEADROOM, NET_SKB_PAD) + NET_IP_ALIGN)
+#define CPSW_HEADROOM ALIGN(CPSW_HEADROOM_NA, sizeof(long))
+
#define for_each_slave(priv, func, arg...) \
do { \
struct cpsw_slave *slave; \
@@ -74,6 +82,8 @@ MODULE_PARM_DESC(descs_pool_size, "Number of CPDMA CPPI descriptors in pool");
(func)(slave++, ##arg); \
} while (0)
+#define CPSW_XMETA_OFFSET ALIGN(sizeof(struct xdp_frame), sizeof(long))
+
static int cpsw_ndo_vlan_rx_add_vid(struct net_device *ndev,
__be16 proto, u16 vid);
@@ -337,24 +347,58 @@ void cpsw_intr_disable(struct cpsw_common *cpsw)
return;
}
[..]
+static int cpsw_xdp_tx_frame_mapped(struct cpsw_priv *priv,
+ struct xdp_frame *xdpf, struct page *page)
+{
+ struct cpsw_common *cpsw = priv->cpsw;
+ struct cpsw_meta_xdp *xmeta;
+ struct netdev_queue *txq;
+ struct cpdma_chan *txch;
+ dma_addr_t dma;
+ int ret;
+
+ xmeta = (void *)xdpf + CPSW_XMETA_OFFSET;
+ xmeta->ch = 0;
+
+ txch = cpsw->txv[0].ch;
+ dma = (xdpf->data - (void *)xdpf) + page->dma_addr;
+ ret = cpdma_chan_submit_mapped(txch, cpsw_xdpf_to_handle(xdpf), dma,
+ xdpf->len,
+ priv->emac_port + cpsw->data.dual_emac);
+ if (ret) {
+ xdp_return_frame_rx_napi(xdpf);
+ goto stop;
+ }
+
+ /* no tx desc - stop sending us tx frames */
+ if (unlikely(!cpdma_check_free_tx_desc(txch)))
+ goto stop;
+
+ return ret;
+stop:
+ txq = netdev_get_tx_queue(priv->ndev, 0);
+ netif_tx_stop_queue(txq);
+
+ /* Barrier, so that stop_queue visible to other cpus */
+ smp_mb__after_atomic();
+
+ if (cpdma_check_free_tx_desc(txch))
+ netif_tx_wake_queue(txq);
+
+ return ret;
+}
+
+static int cpsw_xdp_tx_frame(struct cpsw_priv *priv, struct xdp_frame *xdpf)
+{
+ struct cpsw_common *cpsw = priv->cpsw;
+ struct cpsw_meta_xdp *xmeta;
+ struct netdev_queue *txq;
+ struct cpdma_chan *txch;
+ int ret;
+
+ xmeta = (void *)xdpf + CPSW_XMETA_OFFSET;
+ if (sizeof(*xmeta) > xdpf->headroom)
+ return -EINVAL;
+
+ xmeta->ndev = priv->ndev;
+ xmeta->ch = 0;
+
+ txch = cpsw->txv[0].ch;
+ ret = cpdma_chan_submit(txch, cpsw_xdpf_to_handle(xdpf), xdpf->data,
+ xdpf->len,
+ priv->emac_port + cpsw->data.dual_emac);
+ if (ret) {
+ xdp_return_frame_rx_napi(xdpf);
+ goto stop;
+ }
+
+ /* no tx desc - stop sending us tx frames */
+ if (unlikely(!cpdma_check_free_tx_desc(txch)))
+ goto stop;
+
+ return ret;
+stop:
+ txq = netdev_get_tx_queue(priv->ndev, 0);
+ netif_tx_stop_queue(txq);
+
+ /* Barrier, so that stop_queue visible to other cpus */
+ smp_mb__after_atomic();
+
+ if (cpdma_check_free_tx_desc(txch))
+ netif_tx_wake_queue(txq);
+
+ return ret;
+}
Above 2 functions are mostly identical - could you do smth. with it?
... I know it should be, but i hadn't found better way for combining them ....
+
+static int cpsw_run_xdp(struct cpsw_priv *priv, struct cpsw_vector *rxv,
+ struct xdp_buff *xdp, struct page *page)
+{
+ struct net_device *ndev = priv->ndev;
+ struct xdp_frame *xdpf;
+ struct bpf_prog *prog;
+ int ret = 1;
+ u32 act;
+
+ rcu_read_lock();
+
+ prog = READ_ONCE(priv->xdp_prog);
+ if (!prog) {
+ ret = 0;
+ goto out;
+ }
+
+ act = bpf_prog_run_xdp(prog, xdp);
+ switch (act) {
+ case XDP_PASS:
+ ret = 0;
+ break;
+ case XDP_TX:
+ xdpf = convert_to_xdp_frame(xdp);
+ if (unlikely(!xdpf))
+ xdp_return_buff(xdp);
+ else
+ cpsw_xdp_tx_frame_mapped(priv, xdpf, page);
+ break;
+ case XDP_REDIRECT:
+ if (xdp_do_redirect(ndev, xdp, prog))
+ xdp_return_buff(xdp);
+ else
+ ret = 2;
could we avoid using consts as return values?
may be some informative defines/enum?
Ok, for all "const" cases.
--
Regards,
Ivan Khoronzhuk