xref: /linux/drivers/media/i2c/ccs-pll.c (revision a1c613ae4c322ddd58d5a8539dbfba2a0380a8c0)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * drivers/media/i2c/ccs-pll.c
4  *
5  * Generic MIPI CCS/SMIA/SMIA++ PLL calculator
6  *
7  * Copyright (C) 2020 Intel Corporation
8  * Copyright (C) 2011--2012 Nokia Corporation
9  * Contact: Sakari Ailus <sakari.ailus@linux.intel.com>
10  */
11 
12 #include <linux/device.h>
13 #include <linux/gcd.h>
14 #include <linux/lcm.h>
15 #include <linux/module.h>
16 
17 #include "ccs-pll.h"
18 
19 /* Return an even number or one. */
clk_div_even(u32 a)20 static inline u32 clk_div_even(u32 a)
21 {
22 	return max_t(u32, 1, a & ~1);
23 }
24 
25 /* Return an even number or one. */
clk_div_even_up(u32 a)26 static inline u32 clk_div_even_up(u32 a)
27 {
28 	if (a == 1)
29 		return 1;
30 	return (a + 1) & ~1;
31 }
32 
is_one_or_even(u32 a)33 static inline u32 is_one_or_even(u32 a)
34 {
35 	if (a == 1)
36 		return 1;
37 	if (a & 1)
38 		return 0;
39 
40 	return 1;
41 }
42 
one_or_more(u32 a)43 static inline u32 one_or_more(u32 a)
44 {
45 	return a ?: 1;
46 }
47 
bounds_check(struct device * dev,u32 val,u32 min,u32 max,const char * prefix,char * str)48 static int bounds_check(struct device *dev, u32 val,
49 			u32 min, u32 max, const char *prefix,
50 			char *str)
51 {
52 	if (val >= min && val <= max)
53 		return 0;
54 
55 	dev_dbg(dev, "%s_%s out of bounds: %d (%d--%d)\n", prefix,
56 		str, val, min, max);
57 
58 	return -EINVAL;
59 }
60 
61 #define PLL_OP 1
62 #define PLL_VT 2
63 
pll_string(unsigned int which)64 static const char *pll_string(unsigned int which)
65 {
66 	switch (which) {
67 	case PLL_OP:
68 		return "op";
69 	case PLL_VT:
70 		return "vt";
71 	}
72 
73 	return NULL;
74 }
75 
76 #define PLL_FL(f) CCS_PLL_FLAG_##f
77 
print_pll(struct device * dev,struct ccs_pll * pll)78 static void print_pll(struct device *dev, struct ccs_pll *pll)
79 {
80 	const struct {
81 		struct ccs_pll_branch_fr *fr;
82 		struct ccs_pll_branch_bk *bk;
83 		unsigned int which;
84 	} branches[] = {
85 		{ &pll->vt_fr, &pll->vt_bk, PLL_VT },
86 		{ &pll->op_fr, &pll->op_bk, PLL_OP }
87 	}, *br;
88 	unsigned int i;
89 
90 	dev_dbg(dev, "ext_clk_freq_hz\t\t%u\n", pll->ext_clk_freq_hz);
91 
92 	for (i = 0, br = branches; i < ARRAY_SIZE(branches); i++, br++) {
93 		const char *s = pll_string(br->which);
94 
95 		if (pll->flags & CCS_PLL_FLAG_DUAL_PLL ||
96 		    br->which == PLL_VT) {
97 			dev_dbg(dev, "%s_pre_pll_clk_div\t\t%u\n",  s,
98 				br->fr->pre_pll_clk_div);
99 			dev_dbg(dev, "%s_pll_multiplier\t\t%u\n",  s,
100 				br->fr->pll_multiplier);
101 
102 			dev_dbg(dev, "%s_pll_ip_clk_freq_hz\t%u\n", s,
103 				br->fr->pll_ip_clk_freq_hz);
104 			dev_dbg(dev, "%s_pll_op_clk_freq_hz\t%u\n", s,
105 				br->fr->pll_op_clk_freq_hz);
106 		}
107 
108 		if (!(pll->flags & CCS_PLL_FLAG_NO_OP_CLOCKS) ||
109 		    br->which == PLL_VT) {
110 			dev_dbg(dev, "%s_sys_clk_div\t\t%u\n",  s,
111 				br->bk->sys_clk_div);
112 			dev_dbg(dev, "%s_pix_clk_div\t\t%u\n", s,
113 				br->bk->pix_clk_div);
114 
115 			dev_dbg(dev, "%s_sys_clk_freq_hz\t%u\n", s,
116 				br->bk->sys_clk_freq_hz);
117 			dev_dbg(dev, "%s_pix_clk_freq_hz\t%u\n", s,
118 				br->bk->pix_clk_freq_hz);
119 		}
120 	}
121 
122 	dev_dbg(dev, "pixel rate in pixel array:\t%u\n",
123 		pll->pixel_rate_pixel_array);
124 	dev_dbg(dev, "pixel rate on CSI-2 bus:\t%u\n",
125 		pll->pixel_rate_csi);
126 
127 	dev_dbg(dev, "flags%s%s%s%s%s%s%s%s%s\n",
128 		pll->flags & PLL_FL(LANE_SPEED_MODEL) ? " lane-speed" : "",
129 		pll->flags & PLL_FL(LINK_DECOUPLED) ? " link-decoupled" : "",
130 		pll->flags & PLL_FL(EXT_IP_PLL_DIVIDER) ?
131 		" ext-ip-pll-divider" : "",
132 		pll->flags & PLL_FL(FLEXIBLE_OP_PIX_CLK_DIV) ?
133 		" flexible-op-pix-div" : "",
134 		pll->flags & PLL_FL(FIFO_DERATING) ? " fifo-derating" : "",
135 		pll->flags & PLL_FL(FIFO_OVERRATING) ? " fifo-overrating" : "",
136 		pll->flags & PLL_FL(DUAL_PLL) ? " dual-pll" : "",
137 		pll->flags & PLL_FL(OP_SYS_DDR) ? " op-sys-ddr" : "",
138 		pll->flags & PLL_FL(OP_PIX_DDR) ? " op-pix-ddr" : "");
139 }
140 
op_sys_ddr(u32 flags)141 static u32 op_sys_ddr(u32 flags)
142 {
143 	return flags & CCS_PLL_FLAG_OP_SYS_DDR ? 1 : 0;
144 }
145 
op_pix_ddr(u32 flags)146 static u32 op_pix_ddr(u32 flags)
147 {
148 	return flags & CCS_PLL_FLAG_OP_PIX_DDR ? 1 : 0;
149 }
150 
check_fr_bounds(struct device * dev,const struct ccs_pll_limits * lim,struct ccs_pll * pll,unsigned int which)151 static int check_fr_bounds(struct device *dev,
152 			   const struct ccs_pll_limits *lim,
153 			   struct ccs_pll *pll, unsigned int which)
154 {
155 	const struct ccs_pll_branch_limits_fr *lim_fr;
156 	struct ccs_pll_branch_fr *pll_fr;
157 	const char *s = pll_string(which);
158 	int rval;
159 
160 	if (which == PLL_OP) {
161 		lim_fr = &lim->op_fr;
162 		pll_fr = &pll->op_fr;
163 	} else {
164 		lim_fr = &lim->vt_fr;
165 		pll_fr = &pll->vt_fr;
166 	}
167 
168 	rval = bounds_check(dev, pll_fr->pre_pll_clk_div,
169 			    lim_fr->min_pre_pll_clk_div,
170 			    lim_fr->max_pre_pll_clk_div, s, "pre_pll_clk_div");
171 
172 	if (!rval)
173 		rval = bounds_check(dev, pll_fr->pll_ip_clk_freq_hz,
174 				    lim_fr->min_pll_ip_clk_freq_hz,
175 				    lim_fr->max_pll_ip_clk_freq_hz,
176 				    s, "pll_ip_clk_freq_hz");
177 	if (!rval)
178 		rval = bounds_check(dev, pll_fr->pll_multiplier,
179 				    lim_fr->min_pll_multiplier,
180 				    lim_fr->max_pll_multiplier,
181 				    s, "pll_multiplier");
182 	if (!rval)
183 		rval = bounds_check(dev, pll_fr->pll_op_clk_freq_hz,
184 				    lim_fr->min_pll_op_clk_freq_hz,
185 				    lim_fr->max_pll_op_clk_freq_hz,
186 				    s, "pll_op_clk_freq_hz");
187 
188 	return rval;
189 }
190 
check_bk_bounds(struct device * dev,const struct ccs_pll_limits * lim,struct ccs_pll * pll,unsigned int which)191 static int check_bk_bounds(struct device *dev,
192 			   const struct ccs_pll_limits *lim,
193 			   struct ccs_pll *pll, unsigned int which)
194 {
195 	const struct ccs_pll_branch_limits_bk *lim_bk;
196 	struct ccs_pll_branch_bk *pll_bk;
197 	const char *s = pll_string(which);
198 	int rval;
199 
200 	if (which == PLL_OP) {
201 		if (pll->flags & CCS_PLL_FLAG_NO_OP_CLOCKS)
202 			return 0;
203 
204 		lim_bk = &lim->op_bk;
205 		pll_bk = &pll->op_bk;
206 	} else {
207 		lim_bk = &lim->vt_bk;
208 		pll_bk = &pll->vt_bk;
209 	}
210 
211 	rval = bounds_check(dev, pll_bk->sys_clk_div,
212 			    lim_bk->min_sys_clk_div,
213 			    lim_bk->max_sys_clk_div, s, "op_sys_clk_div");
214 	if (!rval)
215 		rval = bounds_check(dev, pll_bk->sys_clk_freq_hz,
216 				    lim_bk->min_sys_clk_freq_hz,
217 				    lim_bk->max_sys_clk_freq_hz,
218 				    s, "sys_clk_freq_hz");
219 	if (!rval)
220 		rval = bounds_check(dev, pll_bk->sys_clk_div,
221 				    lim_bk->min_sys_clk_div,
222 				    lim_bk->max_sys_clk_div,
223 				    s, "sys_clk_div");
224 	if (!rval)
225 		rval = bounds_check(dev, pll_bk->pix_clk_freq_hz,
226 				    lim_bk->min_pix_clk_freq_hz,
227 				    lim_bk->max_pix_clk_freq_hz,
228 				    s, "pix_clk_freq_hz");
229 
230 	return rval;
231 }
232 
check_ext_bounds(struct device * dev,struct ccs_pll * pll)233 static int check_ext_bounds(struct device *dev, struct ccs_pll *pll)
234 {
235 	if (!(pll->flags & CCS_PLL_FLAG_FIFO_DERATING) &&
236 	    pll->pixel_rate_pixel_array > pll->pixel_rate_csi) {
237 		dev_dbg(dev, "device does not support derating\n");
238 		return -EINVAL;
239 	}
240 
241 	if (!(pll->flags & CCS_PLL_FLAG_FIFO_OVERRATING) &&
242 	    pll->pixel_rate_pixel_array < pll->pixel_rate_csi) {
243 		dev_dbg(dev, "device does not support overrating\n");
244 		return -EINVAL;
245 	}
246 
247 	return 0;
248 }
249 
250 static void
ccs_pll_find_vt_sys_div(struct device * dev,const struct ccs_pll_limits * lim,struct ccs_pll * pll,struct ccs_pll_branch_fr * pll_fr,u16 min_vt_div,u16 max_vt_div,u16 * min_sys_div,u16 * max_sys_div)251 ccs_pll_find_vt_sys_div(struct device *dev, const struct ccs_pll_limits *lim,
252 			struct ccs_pll *pll, struct ccs_pll_branch_fr *pll_fr,
253 			u16 min_vt_div, u16 max_vt_div,
254 			u16 *min_sys_div, u16 *max_sys_div)
255 {
256 	/*
257 	 * Find limits for sys_clk_div. Not all values are possible with all
258 	 * values of pix_clk_div.
259 	 */
260 	*min_sys_div = lim->vt_bk.min_sys_clk_div;
261 	dev_dbg(dev, "min_sys_div: %u\n", *min_sys_div);
262 	*min_sys_div = max_t(u16, *min_sys_div,
263 			     DIV_ROUND_UP(min_vt_div,
264 					  lim->vt_bk.max_pix_clk_div));
265 	dev_dbg(dev, "min_sys_div: max_vt_pix_clk_div: %u\n", *min_sys_div);
266 	*min_sys_div = max_t(u16, *min_sys_div,
267 			     pll_fr->pll_op_clk_freq_hz
268 			     / lim->vt_bk.max_sys_clk_freq_hz);
269 	dev_dbg(dev, "min_sys_div: max_pll_op_clk_freq_hz: %u\n", *min_sys_div);
270 	*min_sys_div = clk_div_even_up(*min_sys_div);
271 	dev_dbg(dev, "min_sys_div: one or even: %u\n", *min_sys_div);
272 
273 	*max_sys_div = lim->vt_bk.max_sys_clk_div;
274 	dev_dbg(dev, "max_sys_div: %u\n", *max_sys_div);
275 	*max_sys_div = min_t(u16, *max_sys_div,
276 			     DIV_ROUND_UP(max_vt_div,
277 					  lim->vt_bk.min_pix_clk_div));
278 	dev_dbg(dev, "max_sys_div: min_vt_pix_clk_div: %u\n", *max_sys_div);
279 	*max_sys_div = min_t(u16, *max_sys_div,
280 			     DIV_ROUND_UP(pll_fr->pll_op_clk_freq_hz,
281 					  lim->vt_bk.min_pix_clk_freq_hz));
282 	dev_dbg(dev, "max_sys_div: min_vt_pix_clk_freq_hz: %u\n", *max_sys_div);
283 }
284 
285 #define CPHY_CONST		7
286 #define DPHY_CONST		16
287 #define PHY_CONST_DIV		16
288 
289 static inline int
__ccs_pll_calculate_vt_tree(struct device * dev,const struct ccs_pll_limits * lim,struct ccs_pll * pll,u32 mul,u32 div)290 __ccs_pll_calculate_vt_tree(struct device *dev,
291 			    const struct ccs_pll_limits *lim,
292 			    struct ccs_pll *pll, u32 mul, u32 div)
293 {
294 	const struct ccs_pll_branch_limits_fr *lim_fr = &lim->vt_fr;
295 	const struct ccs_pll_branch_limits_bk *lim_bk = &lim->vt_bk;
296 	struct ccs_pll_branch_fr *pll_fr = &pll->vt_fr;
297 	struct ccs_pll_branch_bk *pll_bk = &pll->vt_bk;
298 	u32 more_mul;
299 	u16 best_pix_div = SHRT_MAX >> 1, best_div = lim_bk->max_sys_clk_div;
300 	u16 vt_div, min_sys_div, max_sys_div, sys_div;
301 
302 	pll_fr->pll_ip_clk_freq_hz =
303 		pll->ext_clk_freq_hz / pll_fr->pre_pll_clk_div;
304 
305 	dev_dbg(dev, "vt_pll_ip_clk_freq_hz %u\n", pll_fr->pll_ip_clk_freq_hz);
306 
307 	more_mul = one_or_more(DIV_ROUND_UP(lim_fr->min_pll_op_clk_freq_hz,
308 					    pll_fr->pll_ip_clk_freq_hz * mul));
309 
310 	dev_dbg(dev, "more_mul: %u\n", more_mul);
311 	more_mul *= DIV_ROUND_UP(lim_fr->min_pll_multiplier, mul * more_mul);
312 	dev_dbg(dev, "more_mul2: %u\n", more_mul);
313 
314 	pll_fr->pll_multiplier = mul * more_mul;
315 
316 	if (pll_fr->pll_multiplier * pll_fr->pll_ip_clk_freq_hz >
317 	    lim_fr->max_pll_op_clk_freq_hz)
318 		return -EINVAL;
319 
320 	pll_fr->pll_op_clk_freq_hz =
321 		pll_fr->pll_ip_clk_freq_hz * pll_fr->pll_multiplier;
322 
323 	vt_div = div * more_mul;
324 
325 	ccs_pll_find_vt_sys_div(dev, lim, pll, pll_fr, vt_div, vt_div,
326 				&min_sys_div, &max_sys_div);
327 
328 	max_sys_div = (vt_div & 1) ? 1 : max_sys_div;
329 
330 	dev_dbg(dev, "vt min/max_sys_div: %u,%u\n", min_sys_div, max_sys_div);
331 
332 	for (sys_div = min_sys_div; sys_div <= max_sys_div;
333 	     sys_div += 2 - (sys_div & 1)) {
334 		u16 pix_div;
335 
336 		if (vt_div % sys_div)
337 			continue;
338 
339 		pix_div = vt_div / sys_div;
340 
341 		if (pix_div < lim_bk->min_pix_clk_div ||
342 		    pix_div > lim_bk->max_pix_clk_div) {
343 			dev_dbg(dev,
344 				"pix_div %u too small or too big (%u--%u)\n",
345 				pix_div,
346 				lim_bk->min_pix_clk_div,
347 				lim_bk->max_pix_clk_div);
348 			continue;
349 		}
350 
351 		dev_dbg(dev, "sys/pix/best_pix: %u,%u,%u\n", sys_div, pix_div,
352 			best_pix_div);
353 
354 		if (pix_div * sys_div <= best_pix_div) {
355 			best_pix_div = pix_div;
356 			best_div = pix_div * sys_div;
357 		}
358 	}
359 	if (best_pix_div == SHRT_MAX >> 1)
360 		return -EINVAL;
361 
362 	pll_bk->sys_clk_div = best_div / best_pix_div;
363 	pll_bk->pix_clk_div = best_pix_div;
364 
365 	pll_bk->sys_clk_freq_hz =
366 		pll_fr->pll_op_clk_freq_hz / pll_bk->sys_clk_div;
367 	pll_bk->pix_clk_freq_hz =
368 		pll_bk->sys_clk_freq_hz / pll_bk->pix_clk_div;
369 
370 	pll->pixel_rate_pixel_array =
371 		pll_bk->pix_clk_freq_hz * pll->vt_lanes;
372 
373 	return 0;
374 }
375 
ccs_pll_calculate_vt_tree(struct device * dev,const struct ccs_pll_limits * lim,struct ccs_pll * pll)376 static int ccs_pll_calculate_vt_tree(struct device *dev,
377 				     const struct ccs_pll_limits *lim,
378 				     struct ccs_pll *pll)
379 {
380 	const struct ccs_pll_branch_limits_fr *lim_fr = &lim->vt_fr;
381 	struct ccs_pll_branch_fr *pll_fr = &pll->vt_fr;
382 	u16 min_pre_pll_clk_div = lim_fr->min_pre_pll_clk_div;
383 	u16 max_pre_pll_clk_div = lim_fr->max_pre_pll_clk_div;
384 	u32 pre_mul, pre_div;
385 
386 	pre_div = gcd(pll->pixel_rate_csi,
387 		      pll->ext_clk_freq_hz * pll->vt_lanes);
388 	pre_mul = pll->pixel_rate_csi / pre_div;
389 	pre_div = pll->ext_clk_freq_hz * pll->vt_lanes / pre_div;
390 
391 	/* Make sure PLL input frequency is within limits */
392 	max_pre_pll_clk_div =
393 		min_t(u16, max_pre_pll_clk_div,
394 		      DIV_ROUND_UP(pll->ext_clk_freq_hz,
395 				   lim_fr->min_pll_ip_clk_freq_hz));
396 
397 	min_pre_pll_clk_div = max_t(u16, min_pre_pll_clk_div,
398 				    pll->ext_clk_freq_hz /
399 				    lim_fr->max_pll_ip_clk_freq_hz);
400 
401 	dev_dbg(dev, "vt min/max_pre_pll_clk_div: %u,%u\n",
402 		min_pre_pll_clk_div, max_pre_pll_clk_div);
403 
404 	for (pll_fr->pre_pll_clk_div = min_pre_pll_clk_div;
405 	     pll_fr->pre_pll_clk_div <= max_pre_pll_clk_div;
406 	     pll_fr->pre_pll_clk_div +=
407 		     (pll->flags & CCS_PLL_FLAG_EXT_IP_PLL_DIVIDER) ? 1 :
408 		     2 - (pll_fr->pre_pll_clk_div & 1)) {
409 		u32 mul, div;
410 		int rval;
411 
412 		div = gcd(pre_mul * pll_fr->pre_pll_clk_div, pre_div);
413 		mul = pre_mul * pll_fr->pre_pll_clk_div / div;
414 		div = pre_div / div;
415 
416 		dev_dbg(dev, "vt pre-div/mul/div: %u,%u,%u\n",
417 			pll_fr->pre_pll_clk_div, mul, div);
418 
419 		rval = __ccs_pll_calculate_vt_tree(dev, lim, pll,
420 						   mul, div);
421 		if (rval)
422 			continue;
423 
424 		rval = check_fr_bounds(dev, lim, pll, PLL_VT);
425 		if (rval)
426 			continue;
427 
428 		rval = check_bk_bounds(dev, lim, pll, PLL_VT);
429 		if (rval)
430 			continue;
431 
432 		return 0;
433 	}
434 
435 	return -EINVAL;
436 }
437 
438 static void
ccs_pll_calculate_vt(struct device * dev,const struct ccs_pll_limits * lim,const struct ccs_pll_branch_limits_bk * op_lim_bk,struct ccs_pll * pll,struct ccs_pll_branch_fr * pll_fr,struct ccs_pll_branch_bk * op_pll_bk,bool cphy,u32 phy_const)439 ccs_pll_calculate_vt(struct device *dev, const struct ccs_pll_limits *lim,
440 		     const struct ccs_pll_branch_limits_bk *op_lim_bk,
441 		     struct ccs_pll *pll, struct ccs_pll_branch_fr *pll_fr,
442 		     struct ccs_pll_branch_bk *op_pll_bk, bool cphy,
443 		     u32 phy_const)
444 {
445 	u16 sys_div;
446 	u16 best_pix_div = SHRT_MAX >> 1;
447 	u16 vt_op_binning_div;
448 	u16 min_vt_div, max_vt_div, vt_div;
449 	u16 min_sys_div, max_sys_div;
450 
451 	if (pll->flags & CCS_PLL_FLAG_NO_OP_CLOCKS)
452 		goto out_calc_pixel_rate;
453 
454 	/*
455 	 * Find out whether a sensor supports derating. If it does not, VT and
456 	 * OP domains are required to run at the same pixel rate.
457 	 */
458 	if (!(pll->flags & CCS_PLL_FLAG_FIFO_DERATING)) {
459 		min_vt_div =
460 			op_pll_bk->sys_clk_div * op_pll_bk->pix_clk_div
461 			* pll->vt_lanes * phy_const / pll->op_lanes
462 			/ (PHY_CONST_DIV << op_pix_ddr(pll->flags));
463 	} else {
464 		/*
465 		 * Some sensors perform analogue binning and some do this
466 		 * digitally. The ones doing this digitally can be roughly be
467 		 * found out using this formula. The ones doing this digitally
468 		 * should run at higher clock rate, so smaller divisor is used
469 		 * on video timing side.
470 		 */
471 		if (lim->min_line_length_pck_bin > lim->min_line_length_pck
472 		    / pll->binning_horizontal)
473 			vt_op_binning_div = pll->binning_horizontal;
474 		else
475 			vt_op_binning_div = 1;
476 		dev_dbg(dev, "vt_op_binning_div: %u\n", vt_op_binning_div);
477 
478 		/*
479 		 * Profile 2 supports vt_pix_clk_div E [4, 10]
480 		 *
481 		 * Horizontal binning can be used as a base for difference in
482 		 * divisors. One must make sure that horizontal blanking is
483 		 * enough to accommodate the CSI-2 sync codes.
484 		 *
485 		 * Take scaling factor and number of VT lanes into account as well.
486 		 *
487 		 * Find absolute limits for the factor of vt divider.
488 		 */
489 		dev_dbg(dev, "scale_m: %u\n", pll->scale_m);
490 		min_vt_div =
491 			DIV_ROUND_UP(pll->bits_per_pixel
492 				     * op_pll_bk->sys_clk_div * pll->scale_n
493 				     * pll->vt_lanes * phy_const,
494 				     (pll->flags &
495 				      CCS_PLL_FLAG_LANE_SPEED_MODEL ?
496 				      pll->csi2.lanes : 1)
497 				     * vt_op_binning_div * pll->scale_m
498 				     * PHY_CONST_DIV << op_pix_ddr(pll->flags));
499 	}
500 
501 	/* Find smallest and biggest allowed vt divisor. */
502 	dev_dbg(dev, "min_vt_div: %u\n", min_vt_div);
503 	min_vt_div = max_t(u16, min_vt_div,
504 			   DIV_ROUND_UP(pll_fr->pll_op_clk_freq_hz,
505 					lim->vt_bk.max_pix_clk_freq_hz));
506 	dev_dbg(dev, "min_vt_div: max_vt_pix_clk_freq_hz: %u\n",
507 		min_vt_div);
508 	min_vt_div = max_t(u16, min_vt_div, lim->vt_bk.min_pix_clk_div
509 					    * lim->vt_bk.min_sys_clk_div);
510 	dev_dbg(dev, "min_vt_div: min_vt_clk_div: %u\n", min_vt_div);
511 
512 	max_vt_div = lim->vt_bk.max_sys_clk_div * lim->vt_bk.max_pix_clk_div;
513 	dev_dbg(dev, "max_vt_div: %u\n", max_vt_div);
514 	max_vt_div = min_t(u16, max_vt_div,
515 			   DIV_ROUND_UP(pll_fr->pll_op_clk_freq_hz,
516 				      lim->vt_bk.min_pix_clk_freq_hz));
517 	dev_dbg(dev, "max_vt_div: min_vt_pix_clk_freq_hz: %u\n",
518 		max_vt_div);
519 
520 	ccs_pll_find_vt_sys_div(dev, lim, pll, pll_fr, min_vt_div,
521 				max_vt_div, &min_sys_div, &max_sys_div);
522 
523 	/*
524 	 * Find pix_div such that a legal pix_div * sys_div results
525 	 * into a value which is not smaller than div, the desired
526 	 * divisor.
527 	 */
528 	for (vt_div = min_vt_div; vt_div <= max_vt_div; vt_div++) {
529 		u16 __max_sys_div = vt_div & 1 ? 1 : max_sys_div;
530 
531 		for (sys_div = min_sys_div; sys_div <= __max_sys_div;
532 		     sys_div += 2 - (sys_div & 1)) {
533 			u16 pix_div;
534 			u16 rounded_div;
535 
536 			pix_div = DIV_ROUND_UP(vt_div, sys_div);
537 
538 			if (pix_div < lim->vt_bk.min_pix_clk_div
539 			    || pix_div > lim->vt_bk.max_pix_clk_div) {
540 				dev_dbg(dev,
541 					"pix_div %u too small or too big (%u--%u)\n",
542 					pix_div,
543 					lim->vt_bk.min_pix_clk_div,
544 					lim->vt_bk.max_pix_clk_div);
545 				continue;
546 			}
547 
548 			rounded_div = roundup(vt_div, best_pix_div);
549 
550 			/* Check if this one is better. */
551 			if (pix_div * sys_div <= rounded_div)
552 				best_pix_div = pix_div;
553 
554 			/* Bail out if we've already found the best value. */
555 			if (vt_div == rounded_div)
556 				break;
557 		}
558 		if (best_pix_div < SHRT_MAX >> 1)
559 			break;
560 	}
561 
562 	pll->vt_bk.sys_clk_div = DIV_ROUND_UP(vt_div, best_pix_div);
563 	pll->vt_bk.pix_clk_div = best_pix_div;
564 
565 	pll->vt_bk.sys_clk_freq_hz =
566 		pll_fr->pll_op_clk_freq_hz / pll->vt_bk.sys_clk_div;
567 	pll->vt_bk.pix_clk_freq_hz =
568 		pll->vt_bk.sys_clk_freq_hz / pll->vt_bk.pix_clk_div;
569 
570 out_calc_pixel_rate:
571 	pll->pixel_rate_pixel_array =
572 		pll->vt_bk.pix_clk_freq_hz * pll->vt_lanes;
573 }
574 
575 /*
576  * Heuristically guess the PLL tree for a given common multiplier and
577  * divisor. Begin with the operational timing and continue to video
578  * timing once operational timing has been verified.
579  *
580  * @mul is the PLL multiplier and @div is the common divisor
581  * (pre_pll_clk_div and op_sys_clk_div combined). The final PLL
582  * multiplier will be a multiple of @mul.
583  *
584  * @return Zero on success, error code on error.
585  */
586 static int
ccs_pll_calculate_op(struct device * dev,const struct ccs_pll_limits * lim,const struct ccs_pll_branch_limits_fr * op_lim_fr,const struct ccs_pll_branch_limits_bk * op_lim_bk,struct ccs_pll * pll,struct ccs_pll_branch_fr * op_pll_fr,struct ccs_pll_branch_bk * op_pll_bk,u32 mul,u32 div,u32 op_sys_clk_freq_hz_sdr,u32 l,bool cphy,u32 phy_const)587 ccs_pll_calculate_op(struct device *dev, const struct ccs_pll_limits *lim,
588 		     const struct ccs_pll_branch_limits_fr *op_lim_fr,
589 		     const struct ccs_pll_branch_limits_bk *op_lim_bk,
590 		     struct ccs_pll *pll, struct ccs_pll_branch_fr *op_pll_fr,
591 		     struct ccs_pll_branch_bk *op_pll_bk, u32 mul,
592 		     u32 div, u32 op_sys_clk_freq_hz_sdr, u32 l,
593 		     bool cphy, u32 phy_const)
594 {
595 	/*
596 	 * Higher multipliers (and divisors) are often required than
597 	 * necessitated by the external clock and the output clocks.
598 	 * There are limits for all values in the clock tree. These
599 	 * are the minimum and maximum multiplier for mul.
600 	 */
601 	u32 more_mul_min, more_mul_max;
602 	u32 more_mul_factor;
603 	u32 i;
604 
605 	/*
606 	 * Get pre_pll_clk_div so that our pll_op_clk_freq_hz won't be
607 	 * too high.
608 	 */
609 	dev_dbg(dev, "op_pre_pll_clk_div %u\n", op_pll_fr->pre_pll_clk_div);
610 
611 	/* Don't go above max pll multiplier. */
612 	more_mul_max = op_lim_fr->max_pll_multiplier / mul;
613 	dev_dbg(dev, "more_mul_max: max_op_pll_multiplier check: %u\n",
614 		more_mul_max);
615 	/* Don't go above max pll op frequency. */
616 	more_mul_max =
617 		min_t(u32,
618 		      more_mul_max,
619 		      op_lim_fr->max_pll_op_clk_freq_hz
620 		      / (pll->ext_clk_freq_hz /
621 			 op_pll_fr->pre_pll_clk_div * mul));
622 	dev_dbg(dev, "more_mul_max: max_pll_op_clk_freq_hz check: %u\n",
623 		more_mul_max);
624 	/* Don't go above the division capability of op sys clock divider. */
625 	more_mul_max = min(more_mul_max,
626 			   op_lim_bk->max_sys_clk_div * op_pll_fr->pre_pll_clk_div
627 			   / div);
628 	dev_dbg(dev, "more_mul_max: max_op_sys_clk_div check: %u\n",
629 		more_mul_max);
630 	/* Ensure we won't go above max_pll_multiplier. */
631 	more_mul_max = min(more_mul_max, op_lim_fr->max_pll_multiplier / mul);
632 	dev_dbg(dev, "more_mul_max: min_pll_multiplier check: %u\n",
633 		more_mul_max);
634 
635 	/* Ensure we won't go below min_pll_op_clk_freq_hz. */
636 	more_mul_min = DIV_ROUND_UP(op_lim_fr->min_pll_op_clk_freq_hz,
637 				    pll->ext_clk_freq_hz /
638 				    op_pll_fr->pre_pll_clk_div * mul);
639 	dev_dbg(dev, "more_mul_min: min_op_pll_op_clk_freq_hz check: %u\n",
640 		more_mul_min);
641 	/* Ensure we won't go below min_pll_multiplier. */
642 	more_mul_min = max(more_mul_min,
643 			   DIV_ROUND_UP(op_lim_fr->min_pll_multiplier, mul));
644 	dev_dbg(dev, "more_mul_min: min_op_pll_multiplier check: %u\n",
645 		more_mul_min);
646 
647 	if (more_mul_min > more_mul_max) {
648 		dev_dbg(dev,
649 			"unable to compute more_mul_min and more_mul_max\n");
650 		return -EINVAL;
651 	}
652 
653 	more_mul_factor = lcm(div, op_pll_fr->pre_pll_clk_div) / div;
654 	dev_dbg(dev, "more_mul_factor: %u\n", more_mul_factor);
655 	more_mul_factor = lcm(more_mul_factor, op_lim_bk->min_sys_clk_div);
656 	dev_dbg(dev, "more_mul_factor: min_op_sys_clk_div: %d\n",
657 		more_mul_factor);
658 	i = roundup(more_mul_min, more_mul_factor);
659 	if (!is_one_or_even(i))
660 		i <<= 1;
661 
662 	dev_dbg(dev, "final more_mul: %u\n", i);
663 	if (i > more_mul_max) {
664 		dev_dbg(dev, "final more_mul is bad, max %u\n", more_mul_max);
665 		return -EINVAL;
666 	}
667 
668 	op_pll_fr->pll_multiplier = mul * i;
669 	op_pll_bk->sys_clk_div = div * i / op_pll_fr->pre_pll_clk_div;
670 	dev_dbg(dev, "op_sys_clk_div: %u\n", op_pll_bk->sys_clk_div);
671 
672 	op_pll_fr->pll_ip_clk_freq_hz = pll->ext_clk_freq_hz
673 		/ op_pll_fr->pre_pll_clk_div;
674 
675 	op_pll_fr->pll_op_clk_freq_hz = op_pll_fr->pll_ip_clk_freq_hz
676 		* op_pll_fr->pll_multiplier;
677 
678 	if (pll->flags & CCS_PLL_FLAG_LANE_SPEED_MODEL)
679 		op_pll_bk->pix_clk_div =
680 			(pll->bits_per_pixel
681 			 * pll->op_lanes * (phy_const << op_sys_ddr(pll->flags))
682 			 / PHY_CONST_DIV / pll->csi2.lanes / l)
683 			>> op_pix_ddr(pll->flags);
684 	else
685 		op_pll_bk->pix_clk_div =
686 			(pll->bits_per_pixel
687 			 * (phy_const << op_sys_ddr(pll->flags))
688 			 / PHY_CONST_DIV / l) >> op_pix_ddr(pll->flags);
689 
690 	op_pll_bk->pix_clk_freq_hz =
691 		(op_sys_clk_freq_hz_sdr >> op_pix_ddr(pll->flags))
692 		/ op_pll_bk->pix_clk_div;
693 	op_pll_bk->sys_clk_freq_hz =
694 		op_sys_clk_freq_hz_sdr >> op_sys_ddr(pll->flags);
695 
696 	dev_dbg(dev, "op_pix_clk_div: %u\n", op_pll_bk->pix_clk_div);
697 
698 	return 0;
699 }
700 
ccs_pll_calculate(struct device * dev,const struct ccs_pll_limits * lim,struct ccs_pll * pll)701 int ccs_pll_calculate(struct device *dev, const struct ccs_pll_limits *lim,
702 		      struct ccs_pll *pll)
703 {
704 	const struct ccs_pll_branch_limits_fr *op_lim_fr;
705 	const struct ccs_pll_branch_limits_bk *op_lim_bk;
706 	struct ccs_pll_branch_fr *op_pll_fr;
707 	struct ccs_pll_branch_bk *op_pll_bk;
708 	bool cphy = pll->bus_type == CCS_PLL_BUS_TYPE_CSI2_CPHY;
709 	u32 phy_const = cphy ? CPHY_CONST : DPHY_CONST;
710 	u32 op_sys_clk_freq_hz_sdr;
711 	u16 min_op_pre_pll_clk_div;
712 	u16 max_op_pre_pll_clk_div;
713 	u32 mul, div;
714 	u32 l = (!pll->op_bits_per_lane ||
715 		 pll->op_bits_per_lane >= pll->bits_per_pixel) ? 1 : 2;
716 	u32 i;
717 	int rval = -EINVAL;
718 
719 	if (!(pll->flags & CCS_PLL_FLAG_LANE_SPEED_MODEL)) {
720 		pll->op_lanes = 1;
721 		pll->vt_lanes = 1;
722 	}
723 
724 	if (pll->flags & CCS_PLL_FLAG_DUAL_PLL) {
725 		op_lim_fr = &lim->op_fr;
726 		op_lim_bk = &lim->op_bk;
727 		op_pll_fr = &pll->op_fr;
728 		op_pll_bk = &pll->op_bk;
729 	} else if (pll->flags & CCS_PLL_FLAG_NO_OP_CLOCKS) {
730 		/*
731 		 * If there's no OP PLL at all, use the VT values
732 		 * instead. The OP values are ignored for the rest of
733 		 * the PLL calculation.
734 		 */
735 		op_lim_fr = &lim->vt_fr;
736 		op_lim_bk = &lim->vt_bk;
737 		op_pll_fr = &pll->vt_fr;
738 		op_pll_bk = &pll->vt_bk;
739 	} else {
740 		op_lim_fr = &lim->vt_fr;
741 		op_lim_bk = &lim->op_bk;
742 		op_pll_fr = &pll->vt_fr;
743 		op_pll_bk = &pll->op_bk;
744 	}
745 
746 	if (!pll->op_lanes || !pll->vt_lanes || !pll->bits_per_pixel ||
747 	    !pll->ext_clk_freq_hz || !pll->link_freq || !pll->scale_m ||
748 	    !op_lim_fr->min_pll_ip_clk_freq_hz ||
749 	    !op_lim_fr->max_pll_ip_clk_freq_hz ||
750 	    !op_lim_fr->min_pll_op_clk_freq_hz ||
751 	    !op_lim_fr->max_pll_op_clk_freq_hz ||
752 	    !op_lim_bk->max_sys_clk_div || !op_lim_fr->max_pll_multiplier)
753 		return -EINVAL;
754 
755 	/*
756 	 * Make sure op_pix_clk_div will be integer --- unless flexible
757 	 * op_pix_clk_div is supported
758 	 */
759 	if (!(pll->flags & CCS_PLL_FLAG_FLEXIBLE_OP_PIX_CLK_DIV) &&
760 	    (pll->bits_per_pixel * pll->op_lanes) %
761 	    (pll->csi2.lanes * l << op_pix_ddr(pll->flags))) {
762 		dev_dbg(dev, "op_pix_clk_div not an integer (bpp %u, op lanes %u, lanes %u, l %u)\n",
763 			pll->bits_per_pixel, pll->op_lanes, pll->csi2.lanes, l);
764 		return -EINVAL;
765 	}
766 
767 	dev_dbg(dev, "vt_lanes: %u\n", pll->vt_lanes);
768 	dev_dbg(dev, "op_lanes: %u\n", pll->op_lanes);
769 
770 	dev_dbg(dev, "binning: %ux%u\n", pll->binning_horizontal,
771 		pll->binning_vertical);
772 
773 	switch (pll->bus_type) {
774 	case CCS_PLL_BUS_TYPE_CSI2_DPHY:
775 	case CCS_PLL_BUS_TYPE_CSI2_CPHY:
776 		op_sys_clk_freq_hz_sdr = pll->link_freq * 2
777 			* (pll->flags & CCS_PLL_FLAG_LANE_SPEED_MODEL ?
778 			   1 : pll->csi2.lanes);
779 		break;
780 	default:
781 		return -EINVAL;
782 	}
783 
784 	pll->pixel_rate_csi =
785 		div_u64((uint64_t)op_sys_clk_freq_hz_sdr
786 			* (pll->flags & CCS_PLL_FLAG_LANE_SPEED_MODEL ?
787 			   pll->csi2.lanes : 1) * PHY_CONST_DIV,
788 			phy_const * pll->bits_per_pixel * l);
789 
790 	/* Figure out limits for OP pre-pll divider based on extclk */
791 	dev_dbg(dev, "min / max op_pre_pll_clk_div: %u / %u\n",
792 		op_lim_fr->min_pre_pll_clk_div, op_lim_fr->max_pre_pll_clk_div);
793 	max_op_pre_pll_clk_div =
794 		min_t(u16, op_lim_fr->max_pre_pll_clk_div,
795 		      clk_div_even(pll->ext_clk_freq_hz /
796 				   op_lim_fr->min_pll_ip_clk_freq_hz));
797 	min_op_pre_pll_clk_div =
798 		max_t(u16, op_lim_fr->min_pre_pll_clk_div,
799 		      clk_div_even_up(
800 			      DIV_ROUND_UP(pll->ext_clk_freq_hz,
801 					   op_lim_fr->max_pll_ip_clk_freq_hz)));
802 	dev_dbg(dev, "pre-pll check: min / max op_pre_pll_clk_div: %u / %u\n",
803 		min_op_pre_pll_clk_div, max_op_pre_pll_clk_div);
804 
805 	i = gcd(op_sys_clk_freq_hz_sdr,
806 		pll->ext_clk_freq_hz << op_pix_ddr(pll->flags));
807 	mul = op_sys_clk_freq_hz_sdr / i;
808 	div = (pll->ext_clk_freq_hz << op_pix_ddr(pll->flags)) / i;
809 	dev_dbg(dev, "mul %u / div %u\n", mul, div);
810 
811 	min_op_pre_pll_clk_div =
812 		max_t(u16, min_op_pre_pll_clk_div,
813 		      clk_div_even_up(
814 			      mul /
815 			      one_or_more(
816 				      DIV_ROUND_UP(op_lim_fr->max_pll_op_clk_freq_hz,
817 						   pll->ext_clk_freq_hz))));
818 	dev_dbg(dev, "pll_op check: min / max op_pre_pll_clk_div: %u / %u\n",
819 		min_op_pre_pll_clk_div, max_op_pre_pll_clk_div);
820 
821 	for (op_pll_fr->pre_pll_clk_div = min_op_pre_pll_clk_div;
822 	     op_pll_fr->pre_pll_clk_div <= max_op_pre_pll_clk_div;
823 	     op_pll_fr->pre_pll_clk_div +=
824 		     (pll->flags & CCS_PLL_FLAG_EXT_IP_PLL_DIVIDER) ? 1 :
825 		     2 - (op_pll_fr->pre_pll_clk_div & 1)) {
826 		rval = ccs_pll_calculate_op(dev, lim, op_lim_fr, op_lim_bk, pll,
827 					    op_pll_fr, op_pll_bk, mul, div,
828 					    op_sys_clk_freq_hz_sdr, l, cphy,
829 					    phy_const);
830 		if (rval)
831 			continue;
832 
833 		rval = check_fr_bounds(dev, lim, pll,
834 				       pll->flags & CCS_PLL_FLAG_DUAL_PLL ?
835 				       PLL_OP : PLL_VT);
836 		if (rval)
837 			continue;
838 
839 		rval = check_bk_bounds(dev, lim, pll, PLL_OP);
840 		if (rval)
841 			continue;
842 
843 		if (pll->flags & CCS_PLL_FLAG_DUAL_PLL)
844 			break;
845 
846 		ccs_pll_calculate_vt(dev, lim, op_lim_bk, pll, op_pll_fr,
847 				     op_pll_bk, cphy, phy_const);
848 
849 		rval = check_bk_bounds(dev, lim, pll, PLL_VT);
850 		if (rval)
851 			continue;
852 		rval = check_ext_bounds(dev, pll);
853 		if (rval)
854 			continue;
855 
856 		break;
857 	}
858 
859 	if (rval) {
860 		dev_dbg(dev, "unable to compute pre_pll divisor\n");
861 
862 		return rval;
863 	}
864 
865 	if (pll->flags & CCS_PLL_FLAG_DUAL_PLL) {
866 		rval = ccs_pll_calculate_vt_tree(dev, lim, pll);
867 
868 		if (rval)
869 			return rval;
870 	}
871 
872 	print_pll(dev, pll);
873 
874 	return 0;
875 }
876 EXPORT_SYMBOL_GPL(ccs_pll_calculate);
877 
878 MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
879 MODULE_DESCRIPTION("Generic MIPI CCS/SMIA/SMIA++ PLL calculator");
880 MODULE_LICENSE("GPL");
881