xref: /linux/drivers/interconnect/qcom/bcm-voter.c (revision ec8a42e7343234802b9054874fe01810880289ce) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2020, The Linux Foundation. All rights reserved.
4  */
5 
6 #include <asm/div64.h>
7 #include <linux/interconnect-provider.h>
8 #include <linux/list_sort.h>
9 #include <linux/module.h>
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 
13 #include <soc/qcom/rpmh.h>
14 #include <soc/qcom/tcs.h>
15 
16 #include "bcm-voter.h"
17 #include "icc-rpmh.h"
18 
19 static LIST_HEAD(bcm_voters);
20 static DEFINE_MUTEX(bcm_voter_lock);
21 
22 /**
23  * struct bcm_voter - Bus Clock Manager voter
24  * @dev: reference to the device that communicates with the BCM
25  * @np: reference to the device node to match bcm voters
26  * @lock: mutex to protect commit and wake/sleep lists in the voter
27  * @commit_list: list containing bcms to be committed to hardware
28  * @ws_list: list containing bcms that have different wake/sleep votes
29  * @voter_node: list of bcm voters
30  * @tcs_wait: mask for which buckets require TCS completion
31  */
32 struct bcm_voter {
33 	struct device *dev;
34 	struct device_node *np;
35 	struct mutex lock;
36 	struct list_head commit_list;
37 	struct list_head ws_list;
38 	struct list_head voter_node;
39 	u32 tcs_wait;
40 };
41 
42 static int cmp_vcd(void *priv, struct list_head *a, struct list_head *b)
43 {
44 	const struct qcom_icc_bcm *bcm_a = list_entry(a, struct qcom_icc_bcm, list);
45 	const struct qcom_icc_bcm *bcm_b = list_entry(b, struct qcom_icc_bcm, list);
46 
47 	return bcm_a->aux_data.vcd - bcm_b->aux_data.vcd;
48 }
49 
50 static u64 bcm_div(u64 num, u32 base)
51 {
52 	/* Ensure that small votes aren't lost. */
53 	if (num && num < base)
54 		return 1;
55 
56 	do_div(num, base);
57 
58 	return num;
59 }
60 
61 static void bcm_aggregate(struct qcom_icc_bcm *bcm)
62 {
63 	struct qcom_icc_node *node;
64 	size_t i, bucket;
65 	u64 agg_avg[QCOM_ICC_NUM_BUCKETS] = {0};
66 	u64 agg_peak[QCOM_ICC_NUM_BUCKETS] = {0};
67 	u64 temp;
68 
69 	for (bucket = 0; bucket < QCOM_ICC_NUM_BUCKETS; bucket++) {
70 		for (i = 0; i < bcm->num_nodes; i++) {
71 			node = bcm->nodes[i];
72 			temp = bcm_div(node->sum_avg[bucket] * bcm->aux_data.width,
73 				       node->buswidth * node->channels);
74 			agg_avg[bucket] = max(agg_avg[bucket], temp);
75 
76 			temp = bcm_div(node->max_peak[bucket] * bcm->aux_data.width,
77 				       node->buswidth);
78 			agg_peak[bucket] = max(agg_peak[bucket], temp);
79 		}
80 
81 		temp = agg_avg[bucket] * bcm->vote_scale;
82 		bcm->vote_x[bucket] = bcm_div(temp, bcm->aux_data.unit);
83 
84 		temp = agg_peak[bucket] * bcm->vote_scale;
85 		bcm->vote_y[bucket] = bcm_div(temp, bcm->aux_data.unit);
86 	}
87 
88 	if (bcm->keepalive && bcm->vote_x[QCOM_ICC_BUCKET_AMC] == 0 &&
89 	    bcm->vote_y[QCOM_ICC_BUCKET_AMC] == 0) {
90 		bcm->vote_x[QCOM_ICC_BUCKET_AMC] = 1;
91 		bcm->vote_x[QCOM_ICC_BUCKET_WAKE] = 1;
92 		bcm->vote_y[QCOM_ICC_BUCKET_AMC] = 1;
93 		bcm->vote_y[QCOM_ICC_BUCKET_WAKE] = 1;
94 	}
95 }
96 
97 static inline void tcs_cmd_gen(struct tcs_cmd *cmd, u64 vote_x, u64 vote_y,
98 			       u32 addr, bool commit, bool wait)
99 {
100 	bool valid = true;
101 
102 	if (!cmd)
103 		return;
104 
105 	memset(cmd, 0, sizeof(*cmd));
106 
107 	if (vote_x == 0 && vote_y == 0)
108 		valid = false;
109 
110 	if (vote_x > BCM_TCS_CMD_VOTE_MASK)
111 		vote_x = BCM_TCS_CMD_VOTE_MASK;
112 
113 	if (vote_y > BCM_TCS_CMD_VOTE_MASK)
114 		vote_y = BCM_TCS_CMD_VOTE_MASK;
115 
116 	cmd->addr = addr;
117 	cmd->data = BCM_TCS_CMD(commit, valid, vote_x, vote_y);
118 
119 	/*
120 	 * Set the wait for completion flag on command that need to be completed
121 	 * before the next command.
122 	 */
123 	cmd->wait = wait;
124 }
125 
126 static void tcs_list_gen(struct bcm_voter *voter, int bucket,
127 			 struct tcs_cmd tcs_list[MAX_VCD],
128 			 int n[MAX_VCD + 1])
129 {
130 	struct list_head *bcm_list = &voter->commit_list;
131 	struct qcom_icc_bcm *bcm;
132 	bool commit, wait;
133 	size_t idx = 0, batch = 0, cur_vcd_size = 0;
134 
135 	memset(n, 0, sizeof(int) * (MAX_VCD + 1));
136 
137 	list_for_each_entry(bcm, bcm_list, list) {
138 		commit = false;
139 		cur_vcd_size++;
140 		if ((list_is_last(&bcm->list, bcm_list)) ||
141 		    bcm->aux_data.vcd != list_next_entry(bcm, list)->aux_data.vcd) {
142 			commit = true;
143 			cur_vcd_size = 0;
144 		}
145 
146 		wait = commit && (voter->tcs_wait & BIT(bucket));
147 
148 		tcs_cmd_gen(&tcs_list[idx], bcm->vote_x[bucket],
149 			    bcm->vote_y[bucket], bcm->addr, commit, wait);
150 		idx++;
151 		n[batch]++;
152 		/*
153 		 * Batch the BCMs in such a way that we do not split them in
154 		 * multiple payloads when they are under the same VCD. This is
155 		 * to ensure that every BCM is committed since we only set the
156 		 * commit bit on the last BCM request of every VCD.
157 		 */
158 		if (n[batch] >= MAX_RPMH_PAYLOAD) {
159 			if (!commit) {
160 				n[batch] -= cur_vcd_size;
161 				n[batch + 1] = cur_vcd_size;
162 			}
163 			batch++;
164 		}
165 	}
166 }
167 
168 /**
169  * of_bcm_voter_get - gets a bcm voter handle from DT node
170  * @dev: device pointer for the consumer device
171  * @name: name for the bcm voter device
172  *
173  * This function will match a device_node pointer for the phandle
174  * specified in the device DT and return a bcm_voter handle on success.
175  *
176  * Returns bcm_voter pointer or ERR_PTR() on error. EPROBE_DEFER is returned
177  * when matching bcm voter is yet to be found.
178  */
179 struct bcm_voter *of_bcm_voter_get(struct device *dev, const char *name)
180 {
181 	struct bcm_voter *voter = ERR_PTR(-EPROBE_DEFER);
182 	struct bcm_voter *temp;
183 	struct device_node *np, *node;
184 	int idx = 0;
185 
186 	if (!dev || !dev->of_node)
187 		return ERR_PTR(-ENODEV);
188 
189 	np = dev->of_node;
190 
191 	if (name) {
192 		idx = of_property_match_string(np, "qcom,bcm-voter-names", name);
193 		if (idx < 0)
194 			return ERR_PTR(idx);
195 	}
196 
197 	node = of_parse_phandle(np, "qcom,bcm-voters", idx);
198 
199 	mutex_lock(&bcm_voter_lock);
200 	list_for_each_entry(temp, &bcm_voters, voter_node) {
201 		if (temp->np == node) {
202 			voter = temp;
203 			break;
204 		}
205 	}
206 	mutex_unlock(&bcm_voter_lock);
207 
208 	return voter;
209 }
210 EXPORT_SYMBOL_GPL(of_bcm_voter_get);
211 
212 /**
213  * qcom_icc_bcm_voter_add - queues up the bcm nodes that require updates
214  * @voter: voter that the bcms are being added to
215  * @bcm: bcm to add to the commit and wake sleep list
216  */
217 void qcom_icc_bcm_voter_add(struct bcm_voter *voter, struct qcom_icc_bcm *bcm)
218 {
219 	if (!voter)
220 		return;
221 
222 	mutex_lock(&voter->lock);
223 	if (list_empty(&bcm->list))
224 		list_add_tail(&bcm->list, &voter->commit_list);
225 
226 	if (list_empty(&bcm->ws_list))
227 		list_add_tail(&bcm->ws_list, &voter->ws_list);
228 
229 	mutex_unlock(&voter->lock);
230 }
231 EXPORT_SYMBOL_GPL(qcom_icc_bcm_voter_add);
232 
233 /**
234  * qcom_icc_bcm_voter_commit - generates and commits tcs cmds based on bcms
235  * @voter: voter that needs flushing
236  *
237  * This function generates a set of AMC commands and flushes to the BCM device
238  * associated with the voter. It conditionally generate WAKE and SLEEP commands
239  * based on deltas between WAKE/SLEEP requirements. The ws_list persists
240  * through multiple commit requests and bcm nodes are removed only when the
241  * requirements for WAKE matches SLEEP.
242  *
243  * Returns 0 on success, or an appropriate error code otherwise.
244  */
245 int qcom_icc_bcm_voter_commit(struct bcm_voter *voter)
246 {
247 	struct qcom_icc_bcm *bcm;
248 	struct qcom_icc_bcm *bcm_tmp;
249 	int commit_idx[MAX_VCD + 1];
250 	struct tcs_cmd cmds[MAX_BCMS];
251 	int ret = 0;
252 
253 	if (!voter)
254 		return 0;
255 
256 	mutex_lock(&voter->lock);
257 	list_for_each_entry(bcm, &voter->commit_list, list)
258 		bcm_aggregate(bcm);
259 
260 	/*
261 	 * Pre sort the BCMs based on VCD for ease of generating a command list
262 	 * that groups the BCMs with the same VCD together. VCDs are numbered
263 	 * with lowest being the most expensive time wise, ensuring that
264 	 * those commands are being sent the earliest in the queue. This needs
265 	 * to be sorted every commit since we can't guarantee the order in which
266 	 * the BCMs are added to the list.
267 	 */
268 	list_sort(NULL, &voter->commit_list, cmp_vcd);
269 
270 	/*
271 	 * Construct the command list based on a pre ordered list of BCMs
272 	 * based on VCD.
273 	 */
274 	tcs_list_gen(voter, QCOM_ICC_BUCKET_AMC, cmds, commit_idx);
275 	if (!commit_idx[0])
276 		goto out;
277 
278 	rpmh_invalidate(voter->dev);
279 
280 	ret = rpmh_write_batch(voter->dev, RPMH_ACTIVE_ONLY_STATE,
281 			       cmds, commit_idx);
282 	if (ret) {
283 		pr_err("Error sending AMC RPMH requests (%d)\n", ret);
284 		goto out;
285 	}
286 
287 	list_for_each_entry_safe(bcm, bcm_tmp, &voter->commit_list, list)
288 		list_del_init(&bcm->list);
289 
290 	list_for_each_entry_safe(bcm, bcm_tmp, &voter->ws_list, ws_list) {
291 		/*
292 		 * Only generate WAKE and SLEEP commands if a resource's
293 		 * requirements change as the execution environment transitions
294 		 * between different power states.
295 		 */
296 		if (bcm->vote_x[QCOM_ICC_BUCKET_WAKE] !=
297 		    bcm->vote_x[QCOM_ICC_BUCKET_SLEEP] ||
298 		    bcm->vote_y[QCOM_ICC_BUCKET_WAKE] !=
299 		    bcm->vote_y[QCOM_ICC_BUCKET_SLEEP])
300 			list_add_tail(&bcm->list, &voter->commit_list);
301 		else
302 			list_del_init(&bcm->ws_list);
303 	}
304 
305 	if (list_empty(&voter->commit_list))
306 		goto out;
307 
308 	list_sort(NULL, &voter->commit_list, cmp_vcd);
309 
310 	tcs_list_gen(voter, QCOM_ICC_BUCKET_WAKE, cmds, commit_idx);
311 
312 	ret = rpmh_write_batch(voter->dev, RPMH_WAKE_ONLY_STATE, cmds, commit_idx);
313 	if (ret) {
314 		pr_err("Error sending WAKE RPMH requests (%d)\n", ret);
315 		goto out;
316 	}
317 
318 	tcs_list_gen(voter, QCOM_ICC_BUCKET_SLEEP, cmds, commit_idx);
319 
320 	ret = rpmh_write_batch(voter->dev, RPMH_SLEEP_STATE, cmds, commit_idx);
321 	if (ret) {
322 		pr_err("Error sending SLEEP RPMH requests (%d)\n", ret);
323 		goto out;
324 	}
325 
326 out:
327 	list_for_each_entry_safe(bcm, bcm_tmp, &voter->commit_list, list)
328 		list_del_init(&bcm->list);
329 
330 	mutex_unlock(&voter->lock);
331 	return ret;
332 }
333 EXPORT_SYMBOL_GPL(qcom_icc_bcm_voter_commit);
334 
335 static int qcom_icc_bcm_voter_probe(struct platform_device *pdev)
336 {
337 	struct device_node *np = pdev->dev.of_node;
338 	struct bcm_voter *voter;
339 
340 	voter = devm_kzalloc(&pdev->dev, sizeof(*voter), GFP_KERNEL);
341 	if (!voter)
342 		return -ENOMEM;
343 
344 	voter->dev = &pdev->dev;
345 	voter->np = np;
346 
347 	if (of_property_read_u32(np, "qcom,tcs-wait", &voter->tcs_wait))
348 		voter->tcs_wait = QCOM_ICC_TAG_ACTIVE_ONLY;
349 
350 	mutex_init(&voter->lock);
351 	INIT_LIST_HEAD(&voter->commit_list);
352 	INIT_LIST_HEAD(&voter->ws_list);
353 
354 	mutex_lock(&bcm_voter_lock);
355 	list_add_tail(&voter->voter_node, &bcm_voters);
356 	mutex_unlock(&bcm_voter_lock);
357 
358 	return 0;
359 }
360 
361 static const struct of_device_id bcm_voter_of_match[] = {
362 	{ .compatible = "qcom,bcm-voter" },
363 	{ }
364 };
365 
366 static struct platform_driver qcom_icc_bcm_voter_driver = {
367 	.probe = qcom_icc_bcm_voter_probe,
368 	.driver = {
369 		.name		= "bcm_voter",
370 		.of_match_table = bcm_voter_of_match,
371 	},
372 };
373 module_platform_driver(qcom_icc_bcm_voter_driver);
374 
375 MODULE_AUTHOR("David Dai <daidavid1@codeaurora.org>");
376 MODULE_DESCRIPTION("Qualcomm BCM Voter interconnect driver");
377 MODULE_LICENSE("GPL v2");
378