xref: /linux/drivers/net/ethernet/intel/iavf/iavf_txrx.h (revision 69bfec7548f4c1595bac0e3ddfc0458a5af31f4c)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright(c) 2013 - 2018 Intel Corporation. */
3 
4 #ifndef _IAVF_TXRX_H_
5 #define _IAVF_TXRX_H_
6 
7 /* Interrupt Throttling and Rate Limiting Goodies */
8 #define IAVF_DEFAULT_IRQ_WORK      256
9 
10 /* The datasheet for the X710 and XL710 indicate that the maximum value for
11  * the ITR is 8160usec which is then called out as 0xFF0 with a 2usec
12  * resolution. 8160 is 0x1FE0 when written out in hex. So instead of storing
13  * the register value which is divided by 2 lets use the actual values and
14  * avoid an excessive amount of translation.
15  */
16 #define IAVF_ITR_DYNAMIC	0x8000	/* use top bit as a flag */
17 #define IAVF_ITR_MASK		0x1FFE	/* mask for ITR register value */
18 #define IAVF_MIN_ITR		     2	/* reg uses 2 usec resolution */
19 #define IAVF_ITR_100K		    10	/* all values below must be even */
20 #define IAVF_ITR_50K		    20
21 #define IAVF_ITR_20K		    50
22 #define IAVF_ITR_18K		    60
23 #define IAVF_ITR_8K		   122
24 #define IAVF_MAX_ITR		  8160	/* maximum value as per datasheet */
25 #define ITR_TO_REG(setting) ((setting) & ~IAVF_ITR_DYNAMIC)
26 #define ITR_REG_ALIGN(setting) __ALIGN_MASK(setting, ~IAVF_ITR_MASK)
27 #define ITR_IS_DYNAMIC(setting) (!!((setting) & IAVF_ITR_DYNAMIC))
28 
29 #define IAVF_ITR_RX_DEF		(IAVF_ITR_20K | IAVF_ITR_DYNAMIC)
30 #define IAVF_ITR_TX_DEF		(IAVF_ITR_20K | IAVF_ITR_DYNAMIC)
31 
32 /* 0x40 is the enable bit for interrupt rate limiting, and must be set if
33  * the value of the rate limit is non-zero
34  */
35 #define INTRL_ENA                  BIT(6)
36 #define IAVF_MAX_INTRL             0x3B    /* reg uses 4 usec resolution */
37 #define INTRL_REG_TO_USEC(intrl) ((intrl & ~INTRL_ENA) << 2)
38 #define INTRL_USEC_TO_REG(set) ((set) ? ((set) >> 2) | INTRL_ENA : 0)
39 #define IAVF_INTRL_8K              125     /* 8000 ints/sec */
40 #define IAVF_INTRL_62K             16      /* 62500 ints/sec */
41 #define IAVF_INTRL_83K             12      /* 83333 ints/sec */
42 
43 #define IAVF_QUEUE_END_OF_LIST 0x7FF
44 
45 /* this enum matches hardware bits and is meant to be used by DYN_CTLN
46  * registers and QINT registers or more generally anywhere in the manual
47  * mentioning ITR_INDX, ITR_NONE cannot be used as an index 'n' into any
48  * register but instead is a special value meaning "don't update" ITR0/1/2.
49  */
50 enum iavf_dyn_idx_t {
51 	IAVF_IDX_ITR0 = 0,
52 	IAVF_IDX_ITR1 = 1,
53 	IAVF_IDX_ITR2 = 2,
54 	IAVF_ITR_NONE = 3	/* ITR_NONE must not be used as an index */
55 };
56 
57 /* these are indexes into ITRN registers */
58 #define IAVF_RX_ITR    IAVF_IDX_ITR0
59 #define IAVF_TX_ITR    IAVF_IDX_ITR1
60 #define IAVF_PE_ITR    IAVF_IDX_ITR2
61 
62 /* Supported RSS offloads */
63 #define IAVF_DEFAULT_RSS_HENA ( \
64 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_UDP) | \
65 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_SCTP) | \
66 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_TCP) | \
67 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_OTHER) | \
68 	BIT_ULL(IAVF_FILTER_PCTYPE_FRAG_IPV4) | \
69 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_UDP) | \
70 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_TCP) | \
71 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_SCTP) | \
72 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_OTHER) | \
73 	BIT_ULL(IAVF_FILTER_PCTYPE_FRAG_IPV6) | \
74 	BIT_ULL(IAVF_FILTER_PCTYPE_L2_PAYLOAD))
75 
76 #define IAVF_DEFAULT_RSS_HENA_EXPANDED (IAVF_DEFAULT_RSS_HENA | \
77 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV4_TCP_SYN_NO_ACK) | \
78 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_UNICAST_IPV4_UDP) | \
79 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_MULTICAST_IPV4_UDP) | \
80 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_IPV6_TCP_SYN_NO_ACK) | \
81 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_UNICAST_IPV6_UDP) | \
82 	BIT_ULL(IAVF_FILTER_PCTYPE_NONF_MULTICAST_IPV6_UDP))
83 
84 /* Supported Rx Buffer Sizes (a multiple of 128) */
85 #define IAVF_RXBUFFER_256   256
86 #define IAVF_RXBUFFER_1536  1536  /* 128B aligned standard Ethernet frame */
87 #define IAVF_RXBUFFER_2048  2048
88 #define IAVF_RXBUFFER_3072  3072  /* Used for large frames w/ padding */
89 #define IAVF_MAX_RXBUFFER   9728  /* largest size for single descriptor */
90 
91 /* NOTE: netdev_alloc_skb reserves up to 64 bytes, NET_IP_ALIGN means we
92  * reserve 2 more, and skb_shared_info adds an additional 384 bytes more,
93  * this adds up to 512 bytes of extra data meaning the smallest allocation
94  * we could have is 1K.
95  * i.e. RXBUFFER_256 --> 960 byte skb (size-1024 slab)
96  * i.e. RXBUFFER_512 --> 1216 byte skb (size-2048 slab)
97  */
98 #define IAVF_RX_HDR_SIZE IAVF_RXBUFFER_256
99 #define IAVF_PACKET_HDR_PAD (ETH_HLEN + ETH_FCS_LEN + (VLAN_HLEN * 2))
100 #define iavf_rx_desc iavf_32byte_rx_desc
101 
102 #define IAVF_RX_DMA_ATTR \
103 	(DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING)
104 
105 /* Attempt to maximize the headroom available for incoming frames.  We
106  * use a 2K buffer for receives and need 1536/1534 to store the data for
107  * the frame.  This leaves us with 512 bytes of room.  From that we need
108  * to deduct the space needed for the shared info and the padding needed
109  * to IP align the frame.
110  *
111  * Note: For cache line sizes 256 or larger this value is going to end
112  *	 up negative.  In these cases we should fall back to the legacy
113  *	 receive path.
114  */
115 #if (PAGE_SIZE < 8192)
116 #define IAVF_2K_TOO_SMALL_WITH_PADDING \
117 ((NET_SKB_PAD + IAVF_RXBUFFER_1536) > SKB_WITH_OVERHEAD(IAVF_RXBUFFER_2048))
118 
119 static inline int iavf_compute_pad(int rx_buf_len)
120 {
121 	int page_size, pad_size;
122 
123 	page_size = ALIGN(rx_buf_len, PAGE_SIZE / 2);
124 	pad_size = SKB_WITH_OVERHEAD(page_size) - rx_buf_len;
125 
126 	return pad_size;
127 }
128 
129 static inline int iavf_skb_pad(void)
130 {
131 	int rx_buf_len;
132 
133 	/* If a 2K buffer cannot handle a standard Ethernet frame then
134 	 * optimize padding for a 3K buffer instead of a 1.5K buffer.
135 	 *
136 	 * For a 3K buffer we need to add enough padding to allow for
137 	 * tailroom due to NET_IP_ALIGN possibly shifting us out of
138 	 * cache-line alignment.
139 	 */
140 	if (IAVF_2K_TOO_SMALL_WITH_PADDING)
141 		rx_buf_len = IAVF_RXBUFFER_3072 + SKB_DATA_ALIGN(NET_IP_ALIGN);
142 	else
143 		rx_buf_len = IAVF_RXBUFFER_1536;
144 
145 	/* if needed make room for NET_IP_ALIGN */
146 	rx_buf_len -= NET_IP_ALIGN;
147 
148 	return iavf_compute_pad(rx_buf_len);
149 }
150 
151 #define IAVF_SKB_PAD iavf_skb_pad()
152 #else
153 #define IAVF_2K_TOO_SMALL_WITH_PADDING false
154 #define IAVF_SKB_PAD (NET_SKB_PAD + NET_IP_ALIGN)
155 #endif
156 
157 /**
158  * iavf_test_staterr - tests bits in Rx descriptor status and error fields
159  * @rx_desc: pointer to receive descriptor (in le64 format)
160  * @stat_err_bits: value to mask
161  *
162  * This function does some fast chicanery in order to return the
163  * value of the mask which is really only used for boolean tests.
164  * The status_error_len doesn't need to be shifted because it begins
165  * at offset zero.
166  */
167 static inline bool iavf_test_staterr(union iavf_rx_desc *rx_desc,
168 				     const u64 stat_err_bits)
169 {
170 	return !!(rx_desc->wb.qword1.status_error_len &
171 		  cpu_to_le64(stat_err_bits));
172 }
173 
174 /* How many Rx Buffers do we bundle into one write to the hardware ? */
175 #define IAVF_RX_INCREMENT(r, i) \
176 	do {					\
177 		(i)++;				\
178 		if ((i) == (r)->count)		\
179 			i = 0;			\
180 		r->next_to_clean = i;		\
181 	} while (0)
182 
183 #define IAVF_RX_NEXT_DESC(r, i, n)		\
184 	do {					\
185 		(i)++;				\
186 		if ((i) == (r)->count)		\
187 			i = 0;			\
188 		(n) = IAVF_RX_DESC((r), (i));	\
189 	} while (0)
190 
191 #define IAVF_RX_NEXT_DESC_PREFETCH(r, i, n)		\
192 	do {						\
193 		IAVF_RX_NEXT_DESC((r), (i), (n));	\
194 		prefetch((n));				\
195 	} while (0)
196 
197 #define IAVF_MAX_BUFFER_TXD	8
198 #define IAVF_MIN_TX_LEN		17
199 
200 /* The size limit for a transmit buffer in a descriptor is (16K - 1).
201  * In order to align with the read requests we will align the value to
202  * the nearest 4K which represents our maximum read request size.
203  */
204 #define IAVF_MAX_READ_REQ_SIZE		4096
205 #define IAVF_MAX_DATA_PER_TXD		(16 * 1024 - 1)
206 #define IAVF_MAX_DATA_PER_TXD_ALIGNED \
207 	(IAVF_MAX_DATA_PER_TXD & ~(IAVF_MAX_READ_REQ_SIZE - 1))
208 
209 /**
210  * iavf_txd_use_count  - estimate the number of descriptors needed for Tx
211  * @size: transmit request size in bytes
212  *
213  * Due to hardware alignment restrictions (4K alignment), we need to
214  * assume that we can have no more than 12K of data per descriptor, even
215  * though each descriptor can take up to 16K - 1 bytes of aligned memory.
216  * Thus, we need to divide by 12K. But division is slow! Instead,
217  * we decompose the operation into shifts and one relatively cheap
218  * multiply operation.
219  *
220  * To divide by 12K, we first divide by 4K, then divide by 3:
221  *     To divide by 4K, shift right by 12 bits
222  *     To divide by 3, multiply by 85, then divide by 256
223  *     (Divide by 256 is done by shifting right by 8 bits)
224  * Finally, we add one to round up. Because 256 isn't an exact multiple of
225  * 3, we'll underestimate near each multiple of 12K. This is actually more
226  * accurate as we have 4K - 1 of wiggle room that we can fit into the last
227  * segment.  For our purposes this is accurate out to 1M which is orders of
228  * magnitude greater than our largest possible GSO size.
229  *
230  * This would then be implemented as:
231  *     return (((size >> 12) * 85) >> 8) + 1;
232  *
233  * Since multiplication and division are commutative, we can reorder
234  * operations into:
235  *     return ((size * 85) >> 20) + 1;
236  */
237 static inline unsigned int iavf_txd_use_count(unsigned int size)
238 {
239 	return ((size * 85) >> 20) + 1;
240 }
241 
242 /* Tx Descriptors needed, worst case */
243 #define DESC_NEEDED (MAX_SKB_FRAGS + 6)
244 #define IAVF_MIN_DESC_PENDING	4
245 
246 #define IAVF_TX_FLAGS_HW_VLAN			BIT(1)
247 #define IAVF_TX_FLAGS_SW_VLAN			BIT(2)
248 #define IAVF_TX_FLAGS_TSO			BIT(3)
249 #define IAVF_TX_FLAGS_IPV4			BIT(4)
250 #define IAVF_TX_FLAGS_IPV6			BIT(5)
251 #define IAVF_TX_FLAGS_FCCRC			BIT(6)
252 #define IAVF_TX_FLAGS_FSO			BIT(7)
253 #define IAVF_TX_FLAGS_FD_SB			BIT(9)
254 #define IAVF_TX_FLAGS_VXLAN_TUNNEL		BIT(10)
255 #define IAVF_TX_FLAGS_HW_OUTER_SINGLE_VLAN	BIT(11)
256 #define IAVF_TX_FLAGS_VLAN_MASK			0xffff0000
257 #define IAVF_TX_FLAGS_VLAN_PRIO_MASK		0xe0000000
258 #define IAVF_TX_FLAGS_VLAN_PRIO_SHIFT		29
259 #define IAVF_TX_FLAGS_VLAN_SHIFT		16
260 
261 struct iavf_tx_buffer {
262 	struct iavf_tx_desc *next_to_watch;
263 	union {
264 		struct sk_buff *skb;
265 		void *raw_buf;
266 	};
267 	unsigned int bytecount;
268 	unsigned short gso_segs;
269 
270 	DEFINE_DMA_UNMAP_ADDR(dma);
271 	DEFINE_DMA_UNMAP_LEN(len);
272 	u32 tx_flags;
273 };
274 
275 struct iavf_rx_buffer {
276 	dma_addr_t dma;
277 	struct page *page;
278 #if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
279 	__u32 page_offset;
280 #else
281 	__u16 page_offset;
282 #endif
283 	__u16 pagecnt_bias;
284 };
285 
286 struct iavf_queue_stats {
287 	u64 packets;
288 	u64 bytes;
289 };
290 
291 struct iavf_tx_queue_stats {
292 	u64 restart_queue;
293 	u64 tx_busy;
294 	u64 tx_done_old;
295 	u64 tx_linearize;
296 	u64 tx_force_wb;
297 	int prev_pkt_ctr;
298 	u64 tx_lost_interrupt;
299 };
300 
301 struct iavf_rx_queue_stats {
302 	u64 non_eop_descs;
303 	u64 alloc_page_failed;
304 	u64 alloc_buff_failed;
305 	u64 page_reuse_count;
306 	u64 realloc_count;
307 };
308 
309 enum iavf_ring_state_t {
310 	__IAVF_TX_FDIR_INIT_DONE,
311 	__IAVF_TX_XPS_INIT_DONE,
312 	__IAVF_RING_STATE_NBITS /* must be last */
313 };
314 
315 /* some useful defines for virtchannel interface, which
316  * is the only remaining user of header split
317  */
318 #define IAVF_RX_DTYPE_NO_SPLIT      0
319 #define IAVF_RX_DTYPE_HEADER_SPLIT  1
320 #define IAVF_RX_DTYPE_SPLIT_ALWAYS  2
321 #define IAVF_RX_SPLIT_L2      0x1
322 #define IAVF_RX_SPLIT_IP      0x2
323 #define IAVF_RX_SPLIT_TCP_UDP 0x4
324 #define IAVF_RX_SPLIT_SCTP    0x8
325 
326 /* struct that defines a descriptor ring, associated with a VSI */
327 struct iavf_ring {
328 	struct iavf_ring *next;		/* pointer to next ring in q_vector */
329 	void *desc;			/* Descriptor ring memory */
330 	struct device *dev;		/* Used for DMA mapping */
331 	struct net_device *netdev;	/* netdev ring maps to */
332 	union {
333 		struct iavf_tx_buffer *tx_bi;
334 		struct iavf_rx_buffer *rx_bi;
335 	};
336 	DECLARE_BITMAP(state, __IAVF_RING_STATE_NBITS);
337 	u16 queue_index;		/* Queue number of ring */
338 	u8 dcb_tc;			/* Traffic class of ring */
339 	u8 __iomem *tail;
340 
341 	/* high bit set means dynamic, use accessors routines to read/write.
342 	 * hardware only supports 2us resolution for the ITR registers.
343 	 * these values always store the USER setting, and must be converted
344 	 * before programming to a register.
345 	 */
346 	u16 itr_setting;
347 
348 	u16 count;			/* Number of descriptors */
349 	u16 reg_idx;			/* HW register index of the ring */
350 	u16 rx_buf_len;
351 
352 	/* used in interrupt processing */
353 	u16 next_to_use;
354 	u16 next_to_clean;
355 
356 	u8 atr_sample_rate;
357 	u8 atr_count;
358 
359 	bool ring_active;		/* is ring online or not */
360 	bool arm_wb;		/* do something to arm write back */
361 	u8 packet_stride;
362 
363 	u16 flags;
364 #define IAVF_TXR_FLAGS_WB_ON_ITR		BIT(0)
365 #define IAVF_RXR_FLAGS_BUILD_SKB_ENABLED	BIT(1)
366 #define IAVF_TXRX_FLAGS_VLAN_TAG_LOC_L2TAG1	BIT(3)
367 #define IAVF_TXR_FLAGS_VLAN_TAG_LOC_L2TAG2	BIT(4)
368 #define IAVF_RXR_FLAGS_VLAN_TAG_LOC_L2TAG2_2	BIT(5)
369 
370 	/* stats structs */
371 	struct iavf_queue_stats	stats;
372 	struct u64_stats_sync syncp;
373 	union {
374 		struct iavf_tx_queue_stats tx_stats;
375 		struct iavf_rx_queue_stats rx_stats;
376 	};
377 
378 	unsigned int size;		/* length of descriptor ring in bytes */
379 	dma_addr_t dma;			/* physical address of ring */
380 
381 	struct iavf_vsi *vsi;		/* Backreference to associated VSI */
382 	struct iavf_q_vector *q_vector;	/* Backreference to associated vector */
383 
384 	struct rcu_head rcu;		/* to avoid race on free */
385 	u16 next_to_alloc;
386 	struct sk_buff *skb;		/* When iavf_clean_rx_ring_irq() must
387 					 * return before it sees the EOP for
388 					 * the current packet, we save that skb
389 					 * here and resume receiving this
390 					 * packet the next time
391 					 * iavf_clean_rx_ring_irq() is called
392 					 * for this ring.
393 					 */
394 } ____cacheline_internodealigned_in_smp;
395 
396 static inline bool ring_uses_build_skb(struct iavf_ring *ring)
397 {
398 	return !!(ring->flags & IAVF_RXR_FLAGS_BUILD_SKB_ENABLED);
399 }
400 
401 static inline void set_ring_build_skb_enabled(struct iavf_ring *ring)
402 {
403 	ring->flags |= IAVF_RXR_FLAGS_BUILD_SKB_ENABLED;
404 }
405 
406 static inline void clear_ring_build_skb_enabled(struct iavf_ring *ring)
407 {
408 	ring->flags &= ~IAVF_RXR_FLAGS_BUILD_SKB_ENABLED;
409 }
410 
411 #define IAVF_ITR_ADAPTIVE_MIN_INC	0x0002
412 #define IAVF_ITR_ADAPTIVE_MIN_USECS	0x0002
413 #define IAVF_ITR_ADAPTIVE_MAX_USECS	0x007e
414 #define IAVF_ITR_ADAPTIVE_LATENCY	0x8000
415 #define IAVF_ITR_ADAPTIVE_BULK		0x0000
416 #define ITR_IS_BULK(x) (!((x) & IAVF_ITR_ADAPTIVE_LATENCY))
417 
418 struct iavf_ring_container {
419 	struct iavf_ring *ring;		/* pointer to linked list of ring(s) */
420 	unsigned long next_update;	/* jiffies value of next update */
421 	unsigned int total_bytes;	/* total bytes processed this int */
422 	unsigned int total_packets;	/* total packets processed this int */
423 	u16 count;
424 	u16 target_itr;			/* target ITR setting for ring(s) */
425 	u16 current_itr;		/* current ITR setting for ring(s) */
426 };
427 
428 /* iterator for handling rings in ring container */
429 #define iavf_for_each_ring(pos, head) \
430 	for (pos = (head).ring; pos != NULL; pos = pos->next)
431 
432 static inline unsigned int iavf_rx_pg_order(struct iavf_ring *ring)
433 {
434 #if (PAGE_SIZE < 8192)
435 	if (ring->rx_buf_len > (PAGE_SIZE / 2))
436 		return 1;
437 #endif
438 	return 0;
439 }
440 
441 #define iavf_rx_pg_size(_ring) (PAGE_SIZE << iavf_rx_pg_order(_ring))
442 
443 bool iavf_alloc_rx_buffers(struct iavf_ring *rxr, u16 cleaned_count);
444 netdev_tx_t iavf_xmit_frame(struct sk_buff *skb, struct net_device *netdev);
445 void iavf_clean_tx_ring(struct iavf_ring *tx_ring);
446 void iavf_clean_rx_ring(struct iavf_ring *rx_ring);
447 int iavf_setup_tx_descriptors(struct iavf_ring *tx_ring);
448 int iavf_setup_rx_descriptors(struct iavf_ring *rx_ring);
449 void iavf_free_tx_resources(struct iavf_ring *tx_ring);
450 void iavf_free_rx_resources(struct iavf_ring *rx_ring);
451 int iavf_napi_poll(struct napi_struct *napi, int budget);
452 void iavf_force_wb(struct iavf_vsi *vsi, struct iavf_q_vector *q_vector);
453 u32 iavf_get_tx_pending(struct iavf_ring *ring, bool in_sw);
454 void iavf_detect_recover_hung(struct iavf_vsi *vsi);
455 int __iavf_maybe_stop_tx(struct iavf_ring *tx_ring, int size);
456 bool __iavf_chk_linearize(struct sk_buff *skb);
457 
458 /**
459  * iavf_xmit_descriptor_count - calculate number of Tx descriptors needed
460  * @skb:     send buffer
461  *
462  * Returns number of data descriptors needed for this skb. Returns 0 to indicate
463  * there is not enough descriptors available in this ring since we need at least
464  * one descriptor.
465  **/
466 static inline int iavf_xmit_descriptor_count(struct sk_buff *skb)
467 {
468 	const skb_frag_t *frag = &skb_shinfo(skb)->frags[0];
469 	unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
470 	int count = 0, size = skb_headlen(skb);
471 
472 	for (;;) {
473 		count += iavf_txd_use_count(size);
474 
475 		if (!nr_frags--)
476 			break;
477 
478 		size = skb_frag_size(frag++);
479 	}
480 
481 	return count;
482 }
483 
484 /**
485  * iavf_maybe_stop_tx - 1st level check for Tx stop conditions
486  * @tx_ring: the ring to be checked
487  * @size:    the size buffer we want to assure is available
488  *
489  * Returns 0 if stop is not needed
490  **/
491 static inline int iavf_maybe_stop_tx(struct iavf_ring *tx_ring, int size)
492 {
493 	if (likely(IAVF_DESC_UNUSED(tx_ring) >= size))
494 		return 0;
495 	return __iavf_maybe_stop_tx(tx_ring, size);
496 }
497 
498 /**
499  * iavf_chk_linearize - Check if there are more than 8 fragments per packet
500  * @skb:      send buffer
501  * @count:    number of buffers used
502  *
503  * Note: Our HW can't scatter-gather more than 8 fragments to build
504  * a packet on the wire and so we need to figure out the cases where we
505  * need to linearize the skb.
506  **/
507 static inline bool iavf_chk_linearize(struct sk_buff *skb, int count)
508 {
509 	/* Both TSO and single send will work if count is less than 8 */
510 	if (likely(count < IAVF_MAX_BUFFER_TXD))
511 		return false;
512 
513 	if (skb_is_gso(skb))
514 		return __iavf_chk_linearize(skb);
515 
516 	/* we can support up to 8 data buffers for a single send */
517 	return count != IAVF_MAX_BUFFER_TXD;
518 }
519 /**
520  * txring_txq - helper to convert from a ring to a queue
521  * @ring: Tx ring to find the netdev equivalent of
522  **/
523 static inline struct netdev_queue *txring_txq(const struct iavf_ring *ring)
524 {
525 	return netdev_get_tx_queue(ring->netdev, ring->queue_index);
526 }
527 #endif /* _IAVF_TXRX_H_ */
528