1 /*******************************************************************************
2  *
3  * Intel Ethernet Controller XL710 Family Linux Driver
4  * Copyright(c) 2013 - 2016 Intel Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  * You should have received a copy of the GNU General Public License along
16  * with this program.  If not, see <http://www.gnu.org/licenses/>.
17  *
18  * The full GNU General Public License is included in this distribution in
19  * the file called "COPYING".
20  *
21  * Contact Information:
22  * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
23  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
24  *
25  ******************************************************************************/
26 
27 #ifndef _I40E_TXRX_H_
28 #define _I40E_TXRX_H_
29 
30 /* Interrupt Throttling and Rate Limiting Goodies */
31 
32 #define I40E_MAX_ITR               0x0FF0  /* reg uses 2 usec resolution */
33 #define I40E_MIN_ITR               0x0001  /* reg uses 2 usec resolution */
34 #define I40E_ITR_100K              0x0005
35 #define I40E_ITR_50K               0x000A
36 #define I40E_ITR_20K               0x0019
37 #define I40E_ITR_18K               0x001B
38 #define I40E_ITR_8K                0x003E
39 #define I40E_ITR_4K                0x007A
40 #define I40E_MAX_INTRL             0x3B    /* reg uses 4 usec resolution */
41 #define I40E_ITR_RX_DEF            I40E_ITR_20K
42 #define I40E_ITR_TX_DEF            I40E_ITR_20K
43 #define I40E_ITR_DYNAMIC           0x8000  /* use top bit as a flag */
44 #define I40E_MIN_INT_RATE          250     /* ~= 1000000 / (I40E_MAX_ITR * 2) */
45 #define I40E_MAX_INT_RATE          500000  /* == 1000000 / (I40E_MIN_ITR * 2) */
46 #define I40E_DEFAULT_IRQ_WORK      256
47 #define ITR_TO_REG(setting) ((setting & ~I40E_ITR_DYNAMIC) >> 1)
48 #define ITR_IS_DYNAMIC(setting) (!!(setting & I40E_ITR_DYNAMIC))
49 #define ITR_REG_TO_USEC(itr_reg) (itr_reg << 1)
50 /* 0x40 is the enable bit for interrupt rate limiting, and must be set if
51  * the value of the rate limit is non-zero
52  */
53 #define INTRL_ENA                  BIT(6)
54 #define INTRL_REG_TO_USEC(intrl) ((intrl & ~INTRL_ENA) << 2)
55 #define INTRL_USEC_TO_REG(set) ((set) ? ((set) >> 2) | INTRL_ENA : 0)
56 #define I40E_INTRL_8K              125     /* 8000 ints/sec */
57 #define I40E_INTRL_62K             16      /* 62500 ints/sec */
58 #define I40E_INTRL_83K             12      /* 83333 ints/sec */
59 
60 #define I40E_QUEUE_END_OF_LIST 0x7FF
61 
62 /* this enum matches hardware bits and is meant to be used by DYN_CTLN
63  * registers and QINT registers or more generally anywhere in the manual
64  * mentioning ITR_INDX, ITR_NONE cannot be used as an index 'n' into any
65  * register but instead is a special value meaning "don't update" ITR0/1/2.
66  */
67 enum i40e_dyn_idx_t {
68 	I40E_IDX_ITR0 = 0,
69 	I40E_IDX_ITR1 = 1,
70 	I40E_IDX_ITR2 = 2,
71 	I40E_ITR_NONE = 3	/* ITR_NONE must not be used as an index */
72 };
73 
74 /* these are indexes into ITRN registers */
75 #define I40E_RX_ITR    I40E_IDX_ITR0
76 #define I40E_TX_ITR    I40E_IDX_ITR1
77 #define I40E_PE_ITR    I40E_IDX_ITR2
78 
79 /* Supported RSS offloads */
80 #define I40E_DEFAULT_RSS_HENA ( \
81 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_UDP) | \
82 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_SCTP) | \
83 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_TCP) | \
84 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_OTHER) | \
85 	BIT_ULL(I40E_FILTER_PCTYPE_FRAG_IPV4) | \
86 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_UDP) | \
87 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_TCP) | \
88 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_SCTP) | \
89 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_OTHER) | \
90 	BIT_ULL(I40E_FILTER_PCTYPE_FRAG_IPV6) | \
91 	BIT_ULL(I40E_FILTER_PCTYPE_L2_PAYLOAD))
92 
93 #define I40E_DEFAULT_RSS_HENA_EXPANDED (I40E_DEFAULT_RSS_HENA | \
94 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV4_TCP_SYN_NO_ACK) | \
95 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_UNICAST_IPV4_UDP) | \
96 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_MULTICAST_IPV4_UDP) | \
97 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_IPV6_TCP_SYN_NO_ACK) | \
98 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_UNICAST_IPV6_UDP) | \
99 	BIT_ULL(I40E_FILTER_PCTYPE_NONF_MULTICAST_IPV6_UDP))
100 
101 #define i40e_pf_get_default_rss_hena(pf) \
102 	(((pf)->flags & I40E_FLAG_MULTIPLE_TCP_UDP_RSS_PCTYPE) ? \
103 	  I40E_DEFAULT_RSS_HENA_EXPANDED : I40E_DEFAULT_RSS_HENA)
104 
105 /* Supported Rx Buffer Sizes (a multiple of 128) */
106 #define I40E_RXBUFFER_256   256
107 #define I40E_RXBUFFER_2048  2048
108 #define I40E_RXBUFFER_3072  3072   /* For FCoE MTU of 2158 */
109 #define I40E_RXBUFFER_4096  4096
110 #define I40E_RXBUFFER_8192  8192
111 #define I40E_MAX_RXBUFFER   9728  /* largest size for single descriptor */
112 
113 /* NOTE: netdev_alloc_skb reserves up to 64 bytes, NET_IP_ALIGN means we
114  * reserve 2 more, and skb_shared_info adds an additional 384 bytes more,
115  * this adds up to 512 bytes of extra data meaning the smallest allocation
116  * we could have is 1K.
117  * i.e. RXBUFFER_256 --> 960 byte skb (size-1024 slab)
118  * i.e. RXBUFFER_512 --> 1216 byte skb (size-2048 slab)
119  */
120 #define I40E_RX_HDR_SIZE I40E_RXBUFFER_256
121 #define i40e_rx_desc i40e_32byte_rx_desc
122 
123 /**
124  * i40e_test_staterr - tests bits in Rx descriptor status and error fields
125  * @rx_desc: pointer to receive descriptor (in le64 format)
126  * @stat_err_bits: value to mask
127  *
128  * This function does some fast chicanery in order to return the
129  * value of the mask which is really only used for boolean tests.
130  * The status_error_len doesn't need to be shifted because it begins
131  * at offset zero.
132  */
133 static inline bool i40e_test_staterr(union i40e_rx_desc *rx_desc,
134 				     const u64 stat_err_bits)
135 {
136 	return !!(rx_desc->wb.qword1.status_error_len &
137 		  cpu_to_le64(stat_err_bits));
138 }
139 
140 /* How many Rx Buffers do we bundle into one write to the hardware ? */
141 #define I40E_RX_BUFFER_WRITE	16	/* Must be power of 2 */
142 #define I40E_RX_INCREMENT(r, i) \
143 	do {					\
144 		(i)++;				\
145 		if ((i) == (r)->count)		\
146 			i = 0;			\
147 		r->next_to_clean = i;		\
148 	} while (0)
149 
150 #define I40E_RX_NEXT_DESC(r, i, n)		\
151 	do {					\
152 		(i)++;				\
153 		if ((i) == (r)->count)		\
154 			i = 0;			\
155 		(n) = I40E_RX_DESC((r), (i));	\
156 	} while (0)
157 
158 #define I40E_RX_NEXT_DESC_PREFETCH(r, i, n)		\
159 	do {						\
160 		I40E_RX_NEXT_DESC((r), (i), (n));	\
161 		prefetch((n));				\
162 	} while (0)
163 
164 #define I40E_MAX_BUFFER_TXD	8
165 #define I40E_MIN_TX_LEN		17
166 
167 /* The size limit for a transmit buffer in a descriptor is (16K - 1).
168  * In order to align with the read requests we will align the value to
169  * the nearest 4K which represents our maximum read request size.
170  */
171 #define I40E_MAX_READ_REQ_SIZE		4096
172 #define I40E_MAX_DATA_PER_TXD		(16 * 1024 - 1)
173 #define I40E_MAX_DATA_PER_TXD_ALIGNED \
174 	(I40E_MAX_DATA_PER_TXD & ~(I40E_MAX_READ_REQ_SIZE - 1))
175 
176 /**
177  * i40e_txd_use_count  - estimate the number of descriptors needed for Tx
178  * @size: transmit request size in bytes
179  *
180  * Due to hardware alignment restrictions (4K alignment), we need to
181  * assume that we can have no more than 12K of data per descriptor, even
182  * though each descriptor can take up to 16K - 1 bytes of aligned memory.
183  * Thus, we need to divide by 12K. But division is slow! Instead,
184  * we decompose the operation into shifts and one relatively cheap
185  * multiply operation.
186  *
187  * To divide by 12K, we first divide by 4K, then divide by 3:
188  *     To divide by 4K, shift right by 12 bits
189  *     To divide by 3, multiply by 85, then divide by 256
190  *     (Divide by 256 is done by shifting right by 8 bits)
191  * Finally, we add one to round up. Because 256 isn't an exact multiple of
192  * 3, we'll underestimate near each multiple of 12K. This is actually more
193  * accurate as we have 4K - 1 of wiggle room that we can fit into the last
194  * segment.  For our purposes this is accurate out to 1M which is orders of
195  * magnitude greater than our largest possible GSO size.
196  *
197  * This would then be implemented as:
198  *     return (((size >> 12) * 85) >> 8) + 1;
199  *
200  * Since multiplication and division are commutative, we can reorder
201  * operations into:
202  *     return ((size * 85) >> 20) + 1;
203  */
204 static inline unsigned int i40e_txd_use_count(unsigned int size)
205 {
206 	return ((size * 85) >> 20) + 1;
207 }
208 
209 /* Tx Descriptors needed, worst case */
210 #define DESC_NEEDED (MAX_SKB_FRAGS + 4)
211 #define I40E_MIN_DESC_PENDING	4
212 
213 #define I40E_TX_FLAGS_HW_VLAN		BIT(1)
214 #define I40E_TX_FLAGS_SW_VLAN		BIT(2)
215 #define I40E_TX_FLAGS_TSO		BIT(3)
216 #define I40E_TX_FLAGS_IPV4		BIT(4)
217 #define I40E_TX_FLAGS_IPV6		BIT(5)
218 #define I40E_TX_FLAGS_FCCRC		BIT(6)
219 #define I40E_TX_FLAGS_FSO		BIT(7)
220 #define I40E_TX_FLAGS_TSYN		BIT(8)
221 #define I40E_TX_FLAGS_FD_SB		BIT(9)
222 #define I40E_TX_FLAGS_UDP_TUNNEL	BIT(10)
223 #define I40E_TX_FLAGS_VLAN_MASK		0xffff0000
224 #define I40E_TX_FLAGS_VLAN_PRIO_MASK	0xe0000000
225 #define I40E_TX_FLAGS_VLAN_PRIO_SHIFT	29
226 #define I40E_TX_FLAGS_VLAN_SHIFT	16
227 
228 struct i40e_tx_buffer {
229 	struct i40e_tx_desc *next_to_watch;
230 	union {
231 		struct sk_buff *skb;
232 		void *raw_buf;
233 	};
234 	unsigned int bytecount;
235 	unsigned short gso_segs;
236 
237 	DEFINE_DMA_UNMAP_ADDR(dma);
238 	DEFINE_DMA_UNMAP_LEN(len);
239 	u32 tx_flags;
240 };
241 
242 struct i40e_rx_buffer {
243 	struct sk_buff *skb;
244 	dma_addr_t dma;
245 	struct page *page;
246 	unsigned int page_offset;
247 };
248 
249 struct i40e_queue_stats {
250 	u64 packets;
251 	u64 bytes;
252 };
253 
254 struct i40e_tx_queue_stats {
255 	u64 restart_queue;
256 	u64 tx_busy;
257 	u64 tx_done_old;
258 	u64 tx_linearize;
259 	u64 tx_force_wb;
260 	u64 tx_lost_interrupt;
261 };
262 
263 struct i40e_rx_queue_stats {
264 	u64 non_eop_descs;
265 	u64 alloc_page_failed;
266 	u64 alloc_buff_failed;
267 	u64 page_reuse_count;
268 	u64 realloc_count;
269 };
270 
271 enum i40e_ring_state_t {
272 	__I40E_TX_FDIR_INIT_DONE,
273 	__I40E_TX_XPS_INIT_DONE,
274 };
275 
276 /* some useful defines for virtchannel interface, which
277  * is the only remaining user of header split
278  */
279 #define I40E_RX_DTYPE_NO_SPLIT      0
280 #define I40E_RX_DTYPE_HEADER_SPLIT  1
281 #define I40E_RX_DTYPE_SPLIT_ALWAYS  2
282 #define I40E_RX_SPLIT_L2      0x1
283 #define I40E_RX_SPLIT_IP      0x2
284 #define I40E_RX_SPLIT_TCP_UDP 0x4
285 #define I40E_RX_SPLIT_SCTP    0x8
286 
287 /* struct that defines a descriptor ring, associated with a VSI */
288 struct i40e_ring {
289 	struct i40e_ring *next;		/* pointer to next ring in q_vector */
290 	void *desc;			/* Descriptor ring memory */
291 	struct device *dev;		/* Used for DMA mapping */
292 	struct net_device *netdev;	/* netdev ring maps to */
293 	union {
294 		struct i40e_tx_buffer *tx_bi;
295 		struct i40e_rx_buffer *rx_bi;
296 	};
297 	unsigned long state;
298 	u16 queue_index;		/* Queue number of ring */
299 	u8 dcb_tc;			/* Traffic class of ring */
300 	u8 __iomem *tail;
301 
302 	/* high bit set means dynamic, use accessor routines to read/write.
303 	 * hardware only supports 2us resolution for the ITR registers.
304 	 * these values always store the USER setting, and must be converted
305 	 * before programming to a register.
306 	 */
307 	u16 rx_itr_setting;
308 	u16 tx_itr_setting;
309 
310 	u16 count;			/* Number of descriptors */
311 	u16 reg_idx;			/* HW register index of the ring */
312 	u16 rx_buf_len;
313 
314 	/* used in interrupt processing */
315 	u16 next_to_use;
316 	u16 next_to_clean;
317 
318 	u8 atr_sample_rate;
319 	u8 atr_count;
320 
321 	bool ring_active;		/* is ring online or not */
322 	bool arm_wb;		/* do something to arm write back */
323 	u8 packet_stride;
324 
325 	u16 flags;
326 #define I40E_TXR_FLAGS_WB_ON_ITR	BIT(0)
327 
328 	/* stats structs */
329 	struct i40e_queue_stats	stats;
330 	struct u64_stats_sync syncp;
331 	union {
332 		struct i40e_tx_queue_stats tx_stats;
333 		struct i40e_rx_queue_stats rx_stats;
334 	};
335 
336 	unsigned int size;		/* length of descriptor ring in bytes */
337 	dma_addr_t dma;			/* physical address of ring */
338 
339 	struct i40e_vsi *vsi;		/* Backreference to associated VSI */
340 	struct i40e_q_vector *q_vector;	/* Backreference to associated vector */
341 
342 	struct rcu_head rcu;		/* to avoid race on free */
343 	u16 next_to_alloc;
344 } ____cacheline_internodealigned_in_smp;
345 
346 enum i40e_latency_range {
347 	I40E_LOWEST_LATENCY = 0,
348 	I40E_LOW_LATENCY = 1,
349 	I40E_BULK_LATENCY = 2,
350 	I40E_ULTRA_LATENCY = 3,
351 };
352 
353 struct i40e_ring_container {
354 	/* array of pointers to rings */
355 	struct i40e_ring *ring;
356 	unsigned int total_bytes;	/* total bytes processed this int */
357 	unsigned int total_packets;	/* total packets processed this int */
358 	u16 count;
359 	enum i40e_latency_range latency_range;
360 	u16 itr;
361 };
362 
363 /* iterator for handling rings in ring container */
364 #define i40e_for_each_ring(pos, head) \
365 	for (pos = (head).ring; pos != NULL; pos = pos->next)
366 
367 bool i40e_alloc_rx_buffers(struct i40e_ring *rxr, u16 cleaned_count);
368 netdev_tx_t i40e_lan_xmit_frame(struct sk_buff *skb, struct net_device *netdev);
369 void i40e_clean_tx_ring(struct i40e_ring *tx_ring);
370 void i40e_clean_rx_ring(struct i40e_ring *rx_ring);
371 int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring);
372 int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring);
373 void i40e_free_tx_resources(struct i40e_ring *tx_ring);
374 void i40e_free_rx_resources(struct i40e_ring *rx_ring);
375 int i40e_napi_poll(struct napi_struct *napi, int budget);
376 #ifdef I40E_FCOE
377 void i40e_tx_map(struct i40e_ring *tx_ring, struct sk_buff *skb,
378 		 struct i40e_tx_buffer *first, u32 tx_flags,
379 		 const u8 hdr_len, u32 td_cmd, u32 td_offset);
380 int i40e_tx_prepare_vlan_flags(struct sk_buff *skb,
381 			       struct i40e_ring *tx_ring, u32 *flags);
382 #endif
383 void i40e_force_wb(struct i40e_vsi *vsi, struct i40e_q_vector *q_vector);
384 u32 i40e_get_tx_pending(struct i40e_ring *ring, bool in_sw);
385 int __i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size);
386 bool __i40e_chk_linearize(struct sk_buff *skb);
387 
388 /**
389  * i40e_get_head - Retrieve head from head writeback
390  * @tx_ring:  tx ring to fetch head of
391  *
392  * Returns value of Tx ring head based on value stored
393  * in head write-back location
394  **/
395 static inline u32 i40e_get_head(struct i40e_ring *tx_ring)
396 {
397 	void *head = (struct i40e_tx_desc *)tx_ring->desc + tx_ring->count;
398 
399 	return le32_to_cpu(*(volatile __le32 *)head);
400 }
401 
402 /**
403  * i40e_xmit_descriptor_count - calculate number of Tx descriptors needed
404  * @skb:     send buffer
405  * @tx_ring: ring to send buffer on
406  *
407  * Returns number of data descriptors needed for this skb. Returns 0 to indicate
408  * there is not enough descriptors available in this ring since we need at least
409  * one descriptor.
410  **/
411 static inline int i40e_xmit_descriptor_count(struct sk_buff *skb)
412 {
413 	const struct skb_frag_struct *frag = &skb_shinfo(skb)->frags[0];
414 	unsigned int nr_frags = skb_shinfo(skb)->nr_frags;
415 	int count = 0, size = skb_headlen(skb);
416 
417 	for (;;) {
418 		count += i40e_txd_use_count(size);
419 
420 		if (!nr_frags--)
421 			break;
422 
423 		size = skb_frag_size(frag++);
424 	}
425 
426 	return count;
427 }
428 
429 /**
430  * i40e_maybe_stop_tx - 1st level check for Tx stop conditions
431  * @tx_ring: the ring to be checked
432  * @size:    the size buffer we want to assure is available
433  *
434  * Returns 0 if stop is not needed
435  **/
436 static inline int i40e_maybe_stop_tx(struct i40e_ring *tx_ring, int size)
437 {
438 	if (likely(I40E_DESC_UNUSED(tx_ring) >= size))
439 		return 0;
440 	return __i40e_maybe_stop_tx(tx_ring, size);
441 }
442 
443 /**
444  * i40e_chk_linearize - Check if there are more than 8 fragments per packet
445  * @skb:      send buffer
446  * @count:    number of buffers used
447  *
448  * Note: Our HW can't scatter-gather more than 8 fragments to build
449  * a packet on the wire and so we need to figure out the cases where we
450  * need to linearize the skb.
451  **/
452 static inline bool i40e_chk_linearize(struct sk_buff *skb, int count)
453 {
454 	/* Both TSO and single send will work if count is less than 8 */
455 	if (likely(count < I40E_MAX_BUFFER_TXD))
456 		return false;
457 
458 	if (skb_is_gso(skb))
459 		return __i40e_chk_linearize(skb);
460 
461 	/* we can support up to 8 data buffers for a single send */
462 	return count != I40E_MAX_BUFFER_TXD;
463 }
464 
465 /**
466  * i40e_rx_is_fcoe - returns true if the Rx packet type is FCoE
467  * @ptype: the packet type field from Rx descriptor write-back
468  **/
469 static inline bool i40e_rx_is_fcoe(u16 ptype)
470 {
471 	return (ptype >= I40E_RX_PTYPE_L2_FCOE_PAY3) &&
472 	       (ptype <= I40E_RX_PTYPE_L2_FCOE_VFT_FCOTHER);
473 }
474 
475 /**
476  * txring_txq - Find the netdev Tx ring based on the i40e Tx ring
477  * @ring: Tx ring to find the netdev equivalent of
478  **/
479 static inline struct netdev_queue *txring_txq(const struct i40e_ring *ring)
480 {
481 	return netdev_get_tx_queue(ring->netdev, ring->queue_index);
482 }
483 #endif /* _I40E_TXRX_H_ */
484