xref: /linux/drivers/net/ethernet/intel/igc/igc_tsn.c (revision 1c07425e902cd3137961c3d45b4271bf8a9b8eb9)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c)  2019 Intel Corporation */
3 
4 #include "igc.h"
5 #include "igc_tsn.h"
6 
7 static bool is_any_launchtime(struct igc_adapter *adapter)
8 {
9 	int i;
10 
11 	for (i = 0; i < adapter->num_tx_queues; i++) {
12 		struct igc_ring *ring = adapter->tx_ring[i];
13 
14 		if (ring->launchtime_enable)
15 			return true;
16 	}
17 
18 	return false;
19 }
20 
21 static bool is_cbs_enabled(struct igc_adapter *adapter)
22 {
23 	int i;
24 
25 	for (i = 0; i < adapter->num_tx_queues; i++) {
26 		struct igc_ring *ring = adapter->tx_ring[i];
27 
28 		if (ring->cbs_enable)
29 			return true;
30 	}
31 
32 	return false;
33 }
34 
35 static unsigned int igc_tsn_new_flags(struct igc_adapter *adapter)
36 {
37 	unsigned int new_flags = adapter->flags & ~IGC_FLAG_TSN_ANY_ENABLED;
38 
39 	if (adapter->qbv_enable)
40 		new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
41 
42 	if (is_any_launchtime(adapter))
43 		new_flags |= IGC_FLAG_TSN_QBV_ENABLED;
44 
45 	if (is_cbs_enabled(adapter))
46 		new_flags |= IGC_FLAG_TSN_QAV_ENABLED;
47 
48 	return new_flags;
49 }
50 
51 void igc_tsn_adjust_txtime_offset(struct igc_adapter *adapter)
52 {
53 	struct igc_hw *hw = &adapter->hw;
54 	u16 txoffset;
55 
56 	if (!is_any_launchtime(adapter))
57 		return;
58 
59 	switch (adapter->link_speed) {
60 	case SPEED_10:
61 		txoffset = IGC_TXOFFSET_SPEED_10;
62 		break;
63 	case SPEED_100:
64 		txoffset = IGC_TXOFFSET_SPEED_100;
65 		break;
66 	case SPEED_1000:
67 		txoffset = IGC_TXOFFSET_SPEED_1000;
68 		break;
69 	case SPEED_2500:
70 		txoffset = IGC_TXOFFSET_SPEED_2500;
71 		break;
72 	default:
73 		txoffset = 0;
74 		break;
75 	}
76 
77 	wr32(IGC_GTXOFFSET, txoffset);
78 }
79 
80 /* Returns the TSN specific registers to their default values after
81  * the adapter is reset.
82  */
83 static int igc_tsn_disable_offload(struct igc_adapter *adapter)
84 {
85 	struct igc_hw *hw = &adapter->hw;
86 	u32 tqavctrl;
87 	int i;
88 
89 	wr32(IGC_GTXOFFSET, 0);
90 	wr32(IGC_TXPBS, I225_TXPBSIZE_DEFAULT);
91 	wr32(IGC_DTXMXPKTSZ, IGC_DTXMXPKTSZ_DEFAULT);
92 
93 	tqavctrl = rd32(IGC_TQAVCTRL);
94 	tqavctrl &= ~(IGC_TQAVCTRL_TRANSMIT_MODE_TSN |
95 		      IGC_TQAVCTRL_ENHANCED_QAV);
96 	wr32(IGC_TQAVCTRL, tqavctrl);
97 
98 	for (i = 0; i < adapter->num_tx_queues; i++) {
99 		wr32(IGC_TXQCTL(i), 0);
100 		wr32(IGC_STQT(i), 0);
101 		wr32(IGC_ENDQT(i), NSEC_PER_SEC);
102 	}
103 
104 	wr32(IGC_QBVCYCLET_S, 0);
105 	wr32(IGC_QBVCYCLET, NSEC_PER_SEC);
106 
107 	adapter->flags &= ~IGC_FLAG_TSN_QBV_ENABLED;
108 
109 	return 0;
110 }
111 
112 static int igc_tsn_enable_offload(struct igc_adapter *adapter)
113 {
114 	struct igc_hw *hw = &adapter->hw;
115 	u32 tqavctrl, baset_l, baset_h;
116 	u32 sec, nsec, cycle;
117 	ktime_t base_time, systim;
118 	int i;
119 
120 	cycle = adapter->cycle_time;
121 	base_time = adapter->base_time;
122 
123 	wr32(IGC_TSAUXC, 0);
124 	wr32(IGC_DTXMXPKTSZ, IGC_DTXMXPKTSZ_TSN);
125 	wr32(IGC_TXPBS, IGC_TXPBSIZE_TSN);
126 
127 	tqavctrl = rd32(IGC_TQAVCTRL);
128 	tqavctrl |= IGC_TQAVCTRL_TRANSMIT_MODE_TSN | IGC_TQAVCTRL_ENHANCED_QAV;
129 	wr32(IGC_TQAVCTRL, tqavctrl);
130 
131 	wr32(IGC_QBVCYCLET_S, cycle);
132 	wr32(IGC_QBVCYCLET, cycle);
133 
134 	for (i = 0; i < adapter->num_tx_queues; i++) {
135 		struct igc_ring *ring = adapter->tx_ring[i];
136 		u32 txqctl = 0;
137 		u16 cbs_value;
138 		u32 tqavcc;
139 
140 		wr32(IGC_STQT(i), ring->start_time);
141 		wr32(IGC_ENDQT(i), ring->end_time);
142 
143 		txqctl |= IGC_TXQCTL_STRICT_CYCLE |
144 			IGC_TXQCTL_STRICT_END;
145 
146 		if (ring->launchtime_enable)
147 			txqctl |= IGC_TXQCTL_QUEUE_MODE_LAUNCHT;
148 
149 		/* Skip configuring CBS for Q2 and Q3 */
150 		if (i > 1)
151 			goto skip_cbs;
152 
153 		if (ring->cbs_enable) {
154 			if (i == 0)
155 				txqctl |= IGC_TXQCTL_QAV_SEL_CBS0;
156 			else
157 				txqctl |= IGC_TXQCTL_QAV_SEL_CBS1;
158 
159 			/* According to i225 datasheet section 7.5.2.7, we
160 			 * should set the 'idleSlope' field from TQAVCC
161 			 * register following the equation:
162 			 *
163 			 * value = link-speed   0x7736 * BW * 0.2
164 			 *         ---------- *  -----------------         (E1)
165 			 *          100Mbps            2.5
166 			 *
167 			 * Note that 'link-speed' is in Mbps.
168 			 *
169 			 * 'BW' is the percentage bandwidth out of full
170 			 * link speed which can be found with the
171 			 * following equation. Note that idleSlope here
172 			 * is the parameter from this function
173 			 * which is in kbps.
174 			 *
175 			 *     BW =     idleSlope
176 			 *          -----------------                      (E2)
177 			 *          link-speed * 1000
178 			 *
179 			 * That said, we can come up with a generic
180 			 * equation to calculate the value we should set
181 			 * it TQAVCC register by replacing 'BW' in E1 by E2.
182 			 * The resulting equation is:
183 			 *
184 			 * value = link-speed * 0x7736 * idleSlope * 0.2
185 			 *         -------------------------------------   (E3)
186 			 *             100 * 2.5 * link-speed * 1000
187 			 *
188 			 * 'link-speed' is present in both sides of the
189 			 * fraction so it is canceled out. The final
190 			 * equation is the following:
191 			 *
192 			 *     value = idleSlope * 61036
193 			 *             -----------------                   (E4)
194 			 *                  2500000
195 			 *
196 			 * NOTE: For i225, given the above, we can see
197 			 *       that idleslope is represented in
198 			 *       40.959433 kbps units by the value at
199 			 *       the TQAVCC register (2.5Gbps / 61036),
200 			 *       which reduces the granularity for
201 			 *       idleslope increments.
202 			 *
203 			 * In i225 controller, the sendSlope and loCredit
204 			 * parameters from CBS are not configurable
205 			 * by software so we don't do any
206 			 * 'controller configuration' in respect to
207 			 * these parameters.
208 			 */
209 			cbs_value = DIV_ROUND_UP_ULL(ring->idleslope
210 						     * 61036ULL, 2500000);
211 
212 			tqavcc = rd32(IGC_TQAVCC(i));
213 			tqavcc &= ~IGC_TQAVCC_IDLESLOPE_MASK;
214 			tqavcc |= cbs_value | IGC_TQAVCC_KEEP_CREDITS;
215 			wr32(IGC_TQAVCC(i), tqavcc);
216 
217 			wr32(IGC_TQAVHC(i),
218 			     0x80000000 + ring->hicredit * 0x7735);
219 		} else {
220 			/* Disable any CBS for the queue */
221 			txqctl &= ~(IGC_TXQCTL_QAV_SEL_MASK);
222 
223 			/* Set idleSlope to zero. */
224 			tqavcc = rd32(IGC_TQAVCC(i));
225 			tqavcc &= ~(IGC_TQAVCC_IDLESLOPE_MASK |
226 				    IGC_TQAVCC_KEEP_CREDITS);
227 			wr32(IGC_TQAVCC(i), tqavcc);
228 
229 			/* Set hiCredit to zero. */
230 			wr32(IGC_TQAVHC(i), 0);
231 		}
232 skip_cbs:
233 		wr32(IGC_TXQCTL(i), txqctl);
234 	}
235 
236 	nsec = rd32(IGC_SYSTIML);
237 	sec = rd32(IGC_SYSTIMH);
238 
239 	systim = ktime_set(sec, nsec);
240 
241 	if (ktime_compare(systim, base_time) > 0) {
242 		s64 n;
243 
244 		n = div64_s64(ktime_sub_ns(systim, base_time), cycle);
245 		base_time = ktime_add_ns(base_time, (n + 1) * cycle);
246 	}
247 
248 	baset_h = div_s64_rem(base_time, NSEC_PER_SEC, &baset_l);
249 
250 	wr32(IGC_BASET_H, baset_h);
251 	wr32(IGC_BASET_L, baset_l);
252 
253 	return 0;
254 }
255 
256 int igc_tsn_reset(struct igc_adapter *adapter)
257 {
258 	unsigned int new_flags;
259 	int err = 0;
260 
261 	new_flags = igc_tsn_new_flags(adapter);
262 
263 	if (!(new_flags & IGC_FLAG_TSN_ANY_ENABLED))
264 		return igc_tsn_disable_offload(adapter);
265 
266 	err = igc_tsn_enable_offload(adapter);
267 	if (err < 0)
268 		return err;
269 
270 	adapter->flags = new_flags;
271 
272 	return err;
273 }
274 
275 int igc_tsn_offload_apply(struct igc_adapter *adapter)
276 {
277 	int err;
278 
279 	if (netif_running(adapter->netdev)) {
280 		schedule_work(&adapter->reset_task);
281 		return 0;
282 	}
283 
284 	err = igc_tsn_enable_offload(adapter);
285 	if (err < 0)
286 		return err;
287 
288 	adapter->flags = igc_tsn_new_flags(adapter);
289 	return 0;
290 }
291