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Message-ID: <20190527182924.GC4246@khorivan>
Date: Mon, 27 May 2019 21:29:25 +0300
From: Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>
To: grygorii <grygorii.strashko@...com>
Cc: hawk@...nel.org, davem@...emloft.net, ast@...nel.org,
linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org,
xdp-newbies@...r.kernel.org, ilias.apalodimas@...aro.org,
netdev@...r.kernel.org, daniel@...earbox.net,
jakub.kicinski@...ronome.com, john.fastabend@...il.com
Subject: Re: [PATCH net-next 3/3] net: ethernet: ti: cpsw: add XDP support
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@...aro.org>
>>---
>> 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
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