1/* Broadcom NetXtreme-C/E network driver.
2 *
3 * Copyright (c) 2016-2017 Broadcom Limited
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation.
8 */
9#include <linux/kernel.h>
10#include <linux/errno.h>
11#include <linux/pci.h>
12#include <linux/netdevice.h>
13#include <linux/etherdevice.h>
14#include <linux/if_vlan.h>
15#include <linux/bpf.h>
16#include <linux/bpf_trace.h>
17#include <linux/filter.h>
18#include <net/page_pool.h>
19#include "bnxt_hsi.h"
20#include "bnxt.h"
21#include "bnxt_xdp.h"
22
23struct bnxt_sw_tx_bd *bnxt_xmit_bd(struct bnxt *bp,
24				   struct bnxt_tx_ring_info *txr,
25				   dma_addr_t mapping, u32 len)
26{
27	struct bnxt_sw_tx_bd *tx_buf;
28	struct tx_bd *txbd;
29	u32 flags;
30	u16 prod;
31
32	prod = txr->tx_prod;
33	tx_buf = &txr->tx_buf_ring[prod];
34
35	txbd = &txr->tx_desc_ring[TX_RING(prod)][TX_IDX(prod)];
36	flags = (len << TX_BD_LEN_SHIFT) | (1 << TX_BD_FLAGS_BD_CNT_SHIFT) |
37		TX_BD_FLAGS_PACKET_END | bnxt_lhint_arr[len >> 9];
38	txbd->tx_bd_len_flags_type = cpu_to_le32(flags);
39	txbd->tx_bd_opaque = prod;
40	txbd->tx_bd_haddr = cpu_to_le64(mapping);
41
42	prod = NEXT_TX(prod);
43	txr->tx_prod = prod;
44	return tx_buf;
45}
46
47static void __bnxt_xmit_xdp(struct bnxt *bp, struct bnxt_tx_ring_info *txr,
48			    dma_addr_t mapping, u32 len, u16 rx_prod)
49{
50	struct bnxt_sw_tx_bd *tx_buf;
51
52	tx_buf = bnxt_xmit_bd(bp, txr, mapping, len);
53	tx_buf->rx_prod = rx_prod;
54	tx_buf->action = XDP_TX;
55}
56
57static void __bnxt_xmit_xdp_redirect(struct bnxt *bp,
58				     struct bnxt_tx_ring_info *txr,
59				     dma_addr_t mapping, u32 len,
60				     struct xdp_frame *xdpf)
61{
62	struct bnxt_sw_tx_bd *tx_buf;
63
64	tx_buf = bnxt_xmit_bd(bp, txr, mapping, len);
65	tx_buf->action = XDP_REDIRECT;
66	tx_buf->xdpf = xdpf;
67	dma_unmap_addr_set(tx_buf, mapping, mapping);
68	dma_unmap_len_set(tx_buf, len, 0);
69}
70
71void bnxt_tx_int_xdp(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts)
72{
73	struct bnxt_tx_ring_info *txr = bnapi->tx_ring;
74	struct bnxt_rx_ring_info *rxr = bnapi->rx_ring;
75	bool rx_doorbell_needed = false;
76	struct bnxt_sw_tx_bd *tx_buf;
77	u16 tx_cons = txr->tx_cons;
78	u16 last_tx_cons = tx_cons;
79	int i;
80
81	for (i = 0; i < nr_pkts; i++) {
82		tx_buf = &txr->tx_buf_ring[tx_cons];
83
84		if (tx_buf->action == XDP_REDIRECT) {
85			struct pci_dev *pdev = bp->pdev;
86
87			dma_unmap_single(&pdev->dev,
88					 dma_unmap_addr(tx_buf, mapping),
89					 dma_unmap_len(tx_buf, len),
90					 PCI_DMA_TODEVICE);
91			xdp_return_frame(tx_buf->xdpf);
92			tx_buf->action = 0;
93			tx_buf->xdpf = NULL;
94		} else if (tx_buf->action == XDP_TX) {
95			rx_doorbell_needed = true;
96			last_tx_cons = tx_cons;
97		}
98		tx_cons = NEXT_TX(tx_cons);
99	}
100	txr->tx_cons = tx_cons;
101	if (rx_doorbell_needed) {
102		tx_buf = &txr->tx_buf_ring[last_tx_cons];
103		bnxt_db_write(bp, &rxr->rx_db, tx_buf->rx_prod);
104	}
105}
106
107/* returns the following:
108 * true    - packet consumed by XDP and new buffer is allocated.
109 * false   - packet should be passed to the stack.
110 */
111bool bnxt_rx_xdp(struct bnxt *bp, struct bnxt_rx_ring_info *rxr, u16 cons,
112		 struct page *page, u8 **data_ptr, unsigned int *len, u8 *event)
113{
114	struct bpf_prog *xdp_prog = READ_ONCE(rxr->xdp_prog);
115	struct bnxt_tx_ring_info *txr;
116	struct bnxt_sw_rx_bd *rx_buf;
117	struct pci_dev *pdev;
118	struct xdp_buff xdp;
119	dma_addr_t mapping;
120	void *orig_data;
121	u32 tx_avail;
122	u32 offset;
123	u32 act;
124
125	if (!xdp_prog)
126		return false;
127
128	pdev = bp->pdev;
129	rx_buf = &rxr->rx_buf_ring[cons];
130	offset = bp->rx_offset;
131
132	mapping = rx_buf->mapping - bp->rx_dma_offset;
133	dma_sync_single_for_cpu(&pdev->dev, mapping + offset, *len, bp->rx_dir);
134
135	txr = rxr->bnapi->tx_ring;
136	xdp.data_hard_start = *data_ptr - offset;
137	xdp.data = *data_ptr;
138	xdp_set_data_meta_invalid(&xdp);
139	xdp.data_end = *data_ptr + *len;
140	xdp.rxq = &rxr->xdp_rxq;
141	xdp.frame_sz = PAGE_SIZE; /* BNXT_RX_PAGE_MODE(bp) when XDP enabled */
142	orig_data = xdp.data;
143
144	rcu_read_lock();
145	act = bpf_prog_run_xdp(xdp_prog, &xdp);
146	rcu_read_unlock();
147
148	tx_avail = bnxt_tx_avail(bp, txr);
149	/* If the tx ring is not full, we must not update the rx producer yet
150	 * because we may still be transmitting on some BDs.
151	 */
152	if (tx_avail != bp->tx_ring_size)
153		*event &= ~BNXT_RX_EVENT;
154
155	*len = xdp.data_end - xdp.data;
156	if (orig_data != xdp.data) {
157		offset = xdp.data - xdp.data_hard_start;
158		*data_ptr = xdp.data_hard_start + offset;
159	}
160	switch (act) {
161	case XDP_PASS:
162		return false;
163
164	case XDP_TX:
165		if (tx_avail < 1) {
166			trace_xdp_exception(bp->dev, xdp_prog, act);
167			bnxt_reuse_rx_data(rxr, cons, page);
168			return true;
169		}
170
171		*event = BNXT_TX_EVENT;
172		dma_sync_single_for_device(&pdev->dev, mapping + offset, *len,
173					   bp->rx_dir);
174		__bnxt_xmit_xdp(bp, txr, mapping + offset, *len,
175				NEXT_RX(rxr->rx_prod));
176		bnxt_reuse_rx_data(rxr, cons, page);
177		return true;
178	case XDP_REDIRECT:
179		/* if we are calling this here then we know that the
180		 * redirect is coming from a frame received by the
181		 * bnxt_en driver.
182		 */
183		dma_unmap_page_attrs(&pdev->dev, mapping,
184				     PAGE_SIZE, bp->rx_dir,
185				     DMA_ATTR_WEAK_ORDERING);
186
187		/* if we are unable to allocate a new buffer, abort and reuse */
188		if (bnxt_alloc_rx_data(bp, rxr, rxr->rx_prod, GFP_ATOMIC)) {
189			trace_xdp_exception(bp->dev, xdp_prog, act);
190			bnxt_reuse_rx_data(rxr, cons, page);
191			return true;
192		}
193
194		if (xdp_do_redirect(bp->dev, &xdp, xdp_prog)) {
195			trace_xdp_exception(bp->dev, xdp_prog, act);
196			page_pool_recycle_direct(rxr->page_pool, page);
197			return true;
198		}
199
200		*event |= BNXT_REDIRECT_EVENT;
201		break;
202	default:
203		bpf_warn_invalid_xdp_action(act);
204		fallthrough;
205	case XDP_ABORTED:
206		trace_xdp_exception(bp->dev, xdp_prog, act);
207		fallthrough;
208	case XDP_DROP:
209		bnxt_reuse_rx_data(rxr, cons, page);
210		break;
211	}
212	return true;
213}
214
215int bnxt_xdp_xmit(struct net_device *dev, int num_frames,
216		  struct xdp_frame **frames, u32 flags)
217{
218	struct bnxt *bp = netdev_priv(dev);
219	struct bpf_prog *xdp_prog = READ_ONCE(bp->xdp_prog);
220	struct pci_dev *pdev = bp->pdev;
221	struct bnxt_tx_ring_info *txr;
222	dma_addr_t mapping;
223	int drops = 0;
224	int ring;
225	int i;
226
227	if (!test_bit(BNXT_STATE_OPEN, &bp->state) ||
228	    !bp->tx_nr_rings_xdp ||
229	    !xdp_prog)
230		return -EINVAL;
231
232	ring = smp_processor_id() % bp->tx_nr_rings_xdp;
233	txr = &bp->tx_ring[ring];
234
235	for (i = 0; i < num_frames; i++) {
236		struct xdp_frame *xdp = frames[i];
237
238		if (!txr || !bnxt_tx_avail(bp, txr) ||
239		    !(bp->bnapi[ring]->flags & BNXT_NAPI_FLAG_XDP)) {
240			xdp_return_frame_rx_napi(xdp);
241			drops++;
242			continue;
243		}
244
245		mapping = dma_map_single(&pdev->dev, xdp->data, xdp->len,
246					 DMA_TO_DEVICE);
247
248		if (dma_mapping_error(&pdev->dev, mapping)) {
249			xdp_return_frame_rx_napi(xdp);
250			drops++;
251			continue;
252		}
253		__bnxt_xmit_xdp_redirect(bp, txr, mapping, xdp->len, xdp);
254	}
255
256	if (flags & XDP_XMIT_FLUSH) {
257		/* Sync BD data before updating doorbell */
258		wmb();
259		bnxt_db_write(bp, &txr->tx_db, txr->tx_prod);
260	}
261
262	return num_frames - drops;
263}
264
265/* Under rtnl_lock */
266static int bnxt_xdp_set(struct bnxt *bp, struct bpf_prog *prog)
267{
268	struct net_device *dev = bp->dev;
269	int tx_xdp = 0, rc, tc;
270	struct bpf_prog *old;
271
272	if (prog && bp->dev->mtu > BNXT_MAX_PAGE_MODE_MTU) {
273		netdev_warn(dev, "MTU %d larger than largest XDP supported MTU %d.\n",
274			    bp->dev->mtu, BNXT_MAX_PAGE_MODE_MTU);
275		return -EOPNOTSUPP;
276	}
277	if (!(bp->flags & BNXT_FLAG_SHARED_RINGS)) {
278		netdev_warn(dev, "ethtool rx/tx channels must be combined to support XDP.\n");
279		return -EOPNOTSUPP;
280	}
281	if (prog)
282		tx_xdp = bp->rx_nr_rings;
283
284	tc = netdev_get_num_tc(dev);
285	if (!tc)
286		tc = 1;
287	rc = bnxt_check_rings(bp, bp->tx_nr_rings_per_tc, bp->rx_nr_rings,
288			      true, tc, tx_xdp);
289	if (rc) {
290		netdev_warn(dev, "Unable to reserve enough TX rings to support XDP.\n");
291		return rc;
292	}
293	if (netif_running(dev))
294		bnxt_close_nic(bp, true, false);
295
296	old = xchg(&bp->xdp_prog, prog);
297	if (old)
298		bpf_prog_put(old);
299
300	if (prog) {
301		bnxt_set_rx_skb_mode(bp, true);
302	} else {
303		int rx, tx;
304
305		bnxt_set_rx_skb_mode(bp, false);
306		bnxt_get_max_rings(bp, &rx, &tx, true);
307		if (rx > 1) {
308			bp->flags &= ~BNXT_FLAG_NO_AGG_RINGS;
309			bp->dev->hw_features |= NETIF_F_LRO;
310		}
311	}
312	bp->tx_nr_rings_xdp = tx_xdp;
313	bp->tx_nr_rings = bp->tx_nr_rings_per_tc * tc + tx_xdp;
314	bp->cp_nr_rings = max_t(int, bp->tx_nr_rings, bp->rx_nr_rings);
315	bnxt_set_tpa_flags(bp);
316	bnxt_set_ring_params(bp);
317
318	if (netif_running(dev))
319		return bnxt_open_nic(bp, true, false);
320
321	return 0;
322}
323
324int bnxt_xdp(struct net_device *dev, struct netdev_bpf *xdp)
325{
326	struct bnxt *bp = netdev_priv(dev);
327	int rc;
328
329	switch (xdp->command) {
330	case XDP_SETUP_PROG:
331		rc = bnxt_xdp_set(bp, xdp->prog);
332		break;
333	default:
334		rc = -EINVAL;
335		break;
336	}
337	return rc;
338}
339