1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Tegra30 External Memory Controller driver
4  *
5  * Based on downstream driver from NVIDIA and tegra124-emc.c
6  * Copyright (C) 2011-2014 NVIDIA Corporation
7  *
8  * Author: Dmitry Osipenko <digetx@gmail.com>
9  * Copyright (C) 2019 GRATE-DRIVER project
10  */
11 
12 #include <linux/bitfield.h>
13 #include <linux/clk.h>
14 #include <linux/clk/tegra.h>
15 #include <linux/debugfs.h>
16 #include <linux/delay.h>
17 #include <linux/err.h>
18 #include <linux/interconnect-provider.h>
19 #include <linux/interrupt.h>
20 #include <linux/io.h>
21 #include <linux/iopoll.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/mutex.h>
25 #include <linux/of.h>
26 #include <linux/platform_device.h>
27 #include <linux/pm_opp.h>
28 #include <linux/slab.h>
29 #include <linux/sort.h>
30 #include <linux/types.h>
31 
32 #include <soc/tegra/common.h>
33 #include <soc/tegra/fuse.h>
34 
35 #include "../jedec_ddr.h"
36 #include "../of_memory.h"
37 
38 #include "mc.h"
39 
40 #define EMC_INTSTATUS				0x000
41 #define EMC_INTMASK				0x004
42 #define EMC_DBG					0x008
43 #define EMC_ADR_CFG				0x010
44 #define EMC_CFG					0x00c
45 #define EMC_REFCTRL				0x020
46 #define EMC_TIMING_CONTROL			0x028
47 #define EMC_RC					0x02c
48 #define EMC_RFC					0x030
49 #define EMC_RAS					0x034
50 #define EMC_RP					0x038
51 #define EMC_R2W					0x03c
52 #define EMC_W2R					0x040
53 #define EMC_R2P					0x044
54 #define EMC_W2P					0x048
55 #define EMC_RD_RCD				0x04c
56 #define EMC_WR_RCD				0x050
57 #define EMC_RRD					0x054
58 #define EMC_REXT				0x058
59 #define EMC_WDV					0x05c
60 #define EMC_QUSE				0x060
61 #define EMC_QRST				0x064
62 #define EMC_QSAFE				0x068
63 #define EMC_RDV					0x06c
64 #define EMC_REFRESH				0x070
65 #define EMC_BURST_REFRESH_NUM			0x074
66 #define EMC_PDEX2WR				0x078
67 #define EMC_PDEX2RD				0x07c
68 #define EMC_PCHG2PDEN				0x080
69 #define EMC_ACT2PDEN				0x084
70 #define EMC_AR2PDEN				0x088
71 #define EMC_RW2PDEN				0x08c
72 #define EMC_TXSR				0x090
73 #define EMC_TCKE				0x094
74 #define EMC_TFAW				0x098
75 #define EMC_TRPAB				0x09c
76 #define EMC_TCLKSTABLE				0x0a0
77 #define EMC_TCLKSTOP				0x0a4
78 #define EMC_TREFBW				0x0a8
79 #define EMC_QUSE_EXTRA				0x0ac
80 #define EMC_ODT_WRITE				0x0b0
81 #define EMC_ODT_READ				0x0b4
82 #define EMC_WEXT				0x0b8
83 #define EMC_CTT					0x0bc
84 #define EMC_MRS_WAIT_CNT			0x0c8
85 #define EMC_MRS					0x0cc
86 #define EMC_EMRS				0x0d0
87 #define EMC_SELF_REF				0x0e0
88 #define EMC_MRW					0x0e8
89 #define EMC_MRR					0x0ec
90 #define EMC_XM2DQSPADCTRL3			0x0f8
91 #define EMC_FBIO_SPARE				0x100
92 #define EMC_FBIO_CFG5				0x104
93 #define EMC_FBIO_CFG6				0x114
94 #define EMC_CFG_RSV				0x120
95 #define EMC_AUTO_CAL_CONFIG			0x2a4
96 #define EMC_AUTO_CAL_INTERVAL			0x2a8
97 #define EMC_AUTO_CAL_STATUS			0x2ac
98 #define EMC_STATUS				0x2b4
99 #define EMC_CFG_2				0x2b8
100 #define EMC_CFG_DIG_DLL				0x2bc
101 #define EMC_CFG_DIG_DLL_PERIOD			0x2c0
102 #define EMC_CTT_DURATION			0x2d8
103 #define EMC_CTT_TERM_CTRL			0x2dc
104 #define EMC_ZCAL_INTERVAL			0x2e0
105 #define EMC_ZCAL_WAIT_CNT			0x2e4
106 #define EMC_ZQ_CAL				0x2ec
107 #define EMC_XM2CMDPADCTRL			0x2f0
108 #define EMC_XM2DQSPADCTRL2			0x2fc
109 #define EMC_XM2DQPADCTRL2			0x304
110 #define EMC_XM2CLKPADCTRL			0x308
111 #define EMC_XM2COMPPADCTRL			0x30c
112 #define EMC_XM2VTTGENPADCTRL			0x310
113 #define EMC_XM2VTTGENPADCTRL2			0x314
114 #define EMC_XM2QUSEPADCTRL			0x318
115 #define EMC_DLL_XFORM_DQS0			0x328
116 #define EMC_DLL_XFORM_DQS1			0x32c
117 #define EMC_DLL_XFORM_DQS2			0x330
118 #define EMC_DLL_XFORM_DQS3			0x334
119 #define EMC_DLL_XFORM_DQS4			0x338
120 #define EMC_DLL_XFORM_DQS5			0x33c
121 #define EMC_DLL_XFORM_DQS6			0x340
122 #define EMC_DLL_XFORM_DQS7			0x344
123 #define EMC_DLL_XFORM_QUSE0			0x348
124 #define EMC_DLL_XFORM_QUSE1			0x34c
125 #define EMC_DLL_XFORM_QUSE2			0x350
126 #define EMC_DLL_XFORM_QUSE3			0x354
127 #define EMC_DLL_XFORM_QUSE4			0x358
128 #define EMC_DLL_XFORM_QUSE5			0x35c
129 #define EMC_DLL_XFORM_QUSE6			0x360
130 #define EMC_DLL_XFORM_QUSE7			0x364
131 #define EMC_DLL_XFORM_DQ0			0x368
132 #define EMC_DLL_XFORM_DQ1			0x36c
133 #define EMC_DLL_XFORM_DQ2			0x370
134 #define EMC_DLL_XFORM_DQ3			0x374
135 #define EMC_DLI_TRIM_TXDQS0			0x3a8
136 #define EMC_DLI_TRIM_TXDQS1			0x3ac
137 #define EMC_DLI_TRIM_TXDQS2			0x3b0
138 #define EMC_DLI_TRIM_TXDQS3			0x3b4
139 #define EMC_DLI_TRIM_TXDQS4			0x3b8
140 #define EMC_DLI_TRIM_TXDQS5			0x3bc
141 #define EMC_DLI_TRIM_TXDQS6			0x3c0
142 #define EMC_DLI_TRIM_TXDQS7			0x3c4
143 #define EMC_STALL_THEN_EXE_BEFORE_CLKCHANGE	0x3c8
144 #define EMC_STALL_THEN_EXE_AFTER_CLKCHANGE	0x3cc
145 #define EMC_UNSTALL_RW_AFTER_CLKCHANGE		0x3d0
146 #define EMC_SEL_DPD_CTRL			0x3d8
147 #define EMC_PRE_REFRESH_REQ_CNT			0x3dc
148 #define EMC_DYN_SELF_REF_CONTROL		0x3e0
149 #define EMC_TXSRDLL				0x3e4
150 
151 #define EMC_STATUS_TIMING_UPDATE_STALLED	BIT(23)
152 
153 #define EMC_MODE_SET_DLL_RESET			BIT(8)
154 #define EMC_MODE_SET_LONG_CNT			BIT(26)
155 
156 #define EMC_SELF_REF_CMD_ENABLED		BIT(0)
157 
158 #define DRAM_DEV_SEL_ALL			(0 << 30)
159 #define DRAM_DEV_SEL_0				BIT(31)
160 #define DRAM_DEV_SEL_1				BIT(30)
161 #define DRAM_BROADCAST(num) \
162 	((num) > 1 ? DRAM_DEV_SEL_ALL : DRAM_DEV_SEL_0)
163 
164 #define EMC_ZQ_CAL_CMD				BIT(0)
165 #define EMC_ZQ_CAL_LONG				BIT(4)
166 #define EMC_ZQ_CAL_LONG_CMD_DEV0 \
167 	(DRAM_DEV_SEL_0 | EMC_ZQ_CAL_LONG | EMC_ZQ_CAL_CMD)
168 #define EMC_ZQ_CAL_LONG_CMD_DEV1 \
169 	(DRAM_DEV_SEL_1 | EMC_ZQ_CAL_LONG | EMC_ZQ_CAL_CMD)
170 
171 #define EMC_DBG_READ_MUX_ASSEMBLY		BIT(0)
172 #define EMC_DBG_WRITE_MUX_ACTIVE		BIT(1)
173 #define EMC_DBG_FORCE_UPDATE			BIT(2)
174 #define EMC_DBG_CFG_PRIORITY			BIT(24)
175 
176 #define EMC_CFG5_QUSE_MODE_SHIFT		13
177 #define EMC_CFG5_QUSE_MODE_MASK			(7 << EMC_CFG5_QUSE_MODE_SHIFT)
178 
179 #define EMC_CFG5_QUSE_MODE_INTERNAL_LPBK	2
180 #define EMC_CFG5_QUSE_MODE_PULSE_INTERN		3
181 
182 #define EMC_SEL_DPD_CTRL_QUSE_DPD_ENABLE	BIT(9)
183 
184 #define EMC_XM2COMPPADCTRL_VREF_CAL_ENABLE	BIT(10)
185 
186 #define EMC_XM2QUSEPADCTRL_IVREF_ENABLE		BIT(4)
187 
188 #define EMC_XM2DQSPADCTRL2_VREF_ENABLE		BIT(5)
189 #define EMC_XM2DQSPADCTRL3_VREF_ENABLE		BIT(5)
190 
191 #define EMC_AUTO_CAL_STATUS_ACTIVE		BIT(31)
192 
193 #define	EMC_FBIO_CFG5_DRAM_TYPE_MASK		0x3
194 
195 #define EMC_MRS_WAIT_CNT_SHORT_WAIT_MASK	0x3ff
196 #define EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT	16
197 #define EMC_MRS_WAIT_CNT_LONG_WAIT_MASK \
198 	(0x3ff << EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT)
199 
200 #define EMC_REFCTRL_DEV_SEL_MASK		0x3
201 #define EMC_REFCTRL_ENABLE			BIT(31)
202 #define EMC_REFCTRL_ENABLE_ALL(num) \
203 	(((num) > 1 ? 0 : 2) | EMC_REFCTRL_ENABLE)
204 #define EMC_REFCTRL_DISABLE_ALL(num)		((num) > 1 ? 0 : 2)
205 
206 #define EMC_CFG_PERIODIC_QRST			BIT(21)
207 #define EMC_CFG_DYN_SREF_ENABLE			BIT(28)
208 
209 #define EMC_CLKCHANGE_REQ_ENABLE		BIT(0)
210 #define EMC_CLKCHANGE_PD_ENABLE			BIT(1)
211 #define EMC_CLKCHANGE_SR_ENABLE			BIT(2)
212 
213 #define EMC_TIMING_UPDATE			BIT(0)
214 
215 #define EMC_REFRESH_OVERFLOW_INT		BIT(3)
216 #define EMC_CLKCHANGE_COMPLETE_INT		BIT(4)
217 #define EMC_MRR_DIVLD_INT			BIT(5)
218 
219 #define EMC_MRR_DEV_SELECTN			GENMASK(31, 30)
220 #define EMC_MRR_MRR_MA				GENMASK(23, 16)
221 #define EMC_MRR_MRR_DATA			GENMASK(15, 0)
222 
223 #define EMC_ADR_CFG_EMEM_NUMDEV			BIT(0)
224 
225 enum emc_dram_type {
226 	DRAM_TYPE_DDR3,
227 	DRAM_TYPE_DDR1,
228 	DRAM_TYPE_LPDDR2,
229 	DRAM_TYPE_DDR2,
230 };
231 
232 enum emc_dll_change {
233 	DLL_CHANGE_NONE,
234 	DLL_CHANGE_ON,
235 	DLL_CHANGE_OFF
236 };
237 
238 static const u16 emc_timing_registers[] = {
239 	[0] = EMC_RC,
240 	[1] = EMC_RFC,
241 	[2] = EMC_RAS,
242 	[3] = EMC_RP,
243 	[4] = EMC_R2W,
244 	[5] = EMC_W2R,
245 	[6] = EMC_R2P,
246 	[7] = EMC_W2P,
247 	[8] = EMC_RD_RCD,
248 	[9] = EMC_WR_RCD,
249 	[10] = EMC_RRD,
250 	[11] = EMC_REXT,
251 	[12] = EMC_WEXT,
252 	[13] = EMC_WDV,
253 	[14] = EMC_QUSE,
254 	[15] = EMC_QRST,
255 	[16] = EMC_QSAFE,
256 	[17] = EMC_RDV,
257 	[18] = EMC_REFRESH,
258 	[19] = EMC_BURST_REFRESH_NUM,
259 	[20] = EMC_PRE_REFRESH_REQ_CNT,
260 	[21] = EMC_PDEX2WR,
261 	[22] = EMC_PDEX2RD,
262 	[23] = EMC_PCHG2PDEN,
263 	[24] = EMC_ACT2PDEN,
264 	[25] = EMC_AR2PDEN,
265 	[26] = EMC_RW2PDEN,
266 	[27] = EMC_TXSR,
267 	[28] = EMC_TXSRDLL,
268 	[29] = EMC_TCKE,
269 	[30] = EMC_TFAW,
270 	[31] = EMC_TRPAB,
271 	[32] = EMC_TCLKSTABLE,
272 	[33] = EMC_TCLKSTOP,
273 	[34] = EMC_TREFBW,
274 	[35] = EMC_QUSE_EXTRA,
275 	[36] = EMC_FBIO_CFG6,
276 	[37] = EMC_ODT_WRITE,
277 	[38] = EMC_ODT_READ,
278 	[39] = EMC_FBIO_CFG5,
279 	[40] = EMC_CFG_DIG_DLL,
280 	[41] = EMC_CFG_DIG_DLL_PERIOD,
281 	[42] = EMC_DLL_XFORM_DQS0,
282 	[43] = EMC_DLL_XFORM_DQS1,
283 	[44] = EMC_DLL_XFORM_DQS2,
284 	[45] = EMC_DLL_XFORM_DQS3,
285 	[46] = EMC_DLL_XFORM_DQS4,
286 	[47] = EMC_DLL_XFORM_DQS5,
287 	[48] = EMC_DLL_XFORM_DQS6,
288 	[49] = EMC_DLL_XFORM_DQS7,
289 	[50] = EMC_DLL_XFORM_QUSE0,
290 	[51] = EMC_DLL_XFORM_QUSE1,
291 	[52] = EMC_DLL_XFORM_QUSE2,
292 	[53] = EMC_DLL_XFORM_QUSE3,
293 	[54] = EMC_DLL_XFORM_QUSE4,
294 	[55] = EMC_DLL_XFORM_QUSE5,
295 	[56] = EMC_DLL_XFORM_QUSE6,
296 	[57] = EMC_DLL_XFORM_QUSE7,
297 	[58] = EMC_DLI_TRIM_TXDQS0,
298 	[59] = EMC_DLI_TRIM_TXDQS1,
299 	[60] = EMC_DLI_TRIM_TXDQS2,
300 	[61] = EMC_DLI_TRIM_TXDQS3,
301 	[62] = EMC_DLI_TRIM_TXDQS4,
302 	[63] = EMC_DLI_TRIM_TXDQS5,
303 	[64] = EMC_DLI_TRIM_TXDQS6,
304 	[65] = EMC_DLI_TRIM_TXDQS7,
305 	[66] = EMC_DLL_XFORM_DQ0,
306 	[67] = EMC_DLL_XFORM_DQ1,
307 	[68] = EMC_DLL_XFORM_DQ2,
308 	[69] = EMC_DLL_XFORM_DQ3,
309 	[70] = EMC_XM2CMDPADCTRL,
310 	[71] = EMC_XM2DQSPADCTRL2,
311 	[72] = EMC_XM2DQPADCTRL2,
312 	[73] = EMC_XM2CLKPADCTRL,
313 	[74] = EMC_XM2COMPPADCTRL,
314 	[75] = EMC_XM2VTTGENPADCTRL,
315 	[76] = EMC_XM2VTTGENPADCTRL2,
316 	[77] = EMC_XM2QUSEPADCTRL,
317 	[78] = EMC_XM2DQSPADCTRL3,
318 	[79] = EMC_CTT_TERM_CTRL,
319 	[80] = EMC_ZCAL_INTERVAL,
320 	[81] = EMC_ZCAL_WAIT_CNT,
321 	[82] = EMC_MRS_WAIT_CNT,
322 	[83] = EMC_AUTO_CAL_CONFIG,
323 	[84] = EMC_CTT,
324 	[85] = EMC_CTT_DURATION,
325 	[86] = EMC_DYN_SELF_REF_CONTROL,
326 	[87] = EMC_FBIO_SPARE,
327 	[88] = EMC_CFG_RSV,
328 };
329 
330 struct emc_timing {
331 	unsigned long rate;
332 
333 	u32 data[ARRAY_SIZE(emc_timing_registers)];
334 
335 	u32 emc_auto_cal_interval;
336 	u32 emc_mode_1;
337 	u32 emc_mode_2;
338 	u32 emc_mode_reset;
339 	u32 emc_zcal_cnt_long;
340 	bool emc_cfg_periodic_qrst;
341 	bool emc_cfg_dyn_self_ref;
342 };
343 
344 enum emc_rate_request_type {
345 	EMC_RATE_DEBUG,
346 	EMC_RATE_ICC,
347 	EMC_RATE_TYPE_MAX,
348 };
349 
350 struct emc_rate_request {
351 	unsigned long min_rate;
352 	unsigned long max_rate;
353 };
354 
355 struct tegra_emc {
356 	struct device *dev;
357 	struct tegra_mc *mc;
358 	struct icc_provider provider;
359 	struct notifier_block clk_nb;
360 	struct clk *clk;
361 	void __iomem *regs;
362 	unsigned int irq;
363 	bool bad_state;
364 
365 	struct emc_timing *new_timing;
366 	struct emc_timing *timings;
367 	unsigned int num_timings;
368 
369 	u32 mc_override;
370 	u32 emc_cfg;
371 
372 	u32 emc_mode_1;
373 	u32 emc_mode_2;
374 	u32 emc_mode_reset;
375 
376 	bool vref_cal_toggle : 1;
377 	bool zcal_long : 1;
378 	bool dll_on : 1;
379 
380 	struct {
381 		struct dentry *root;
382 		unsigned long min_rate;
383 		unsigned long max_rate;
384 	} debugfs;
385 
386 	/*
387 	 * There are multiple sources in the EMC driver which could request
388 	 * a min/max clock rate, these rates are contained in this array.
389 	 */
390 	struct emc_rate_request requested_rate[EMC_RATE_TYPE_MAX];
391 
392 	/* protect shared rate-change code path */
393 	struct mutex rate_lock;
394 
395 	bool mrr_error;
396 };
397 
emc_seq_update_timing(struct tegra_emc * emc)398 static int emc_seq_update_timing(struct tegra_emc *emc)
399 {
400 	u32 val;
401 	int err;
402 
403 	writel_relaxed(EMC_TIMING_UPDATE, emc->regs + EMC_TIMING_CONTROL);
404 
405 	err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_STATUS, val,
406 				!(val & EMC_STATUS_TIMING_UPDATE_STALLED),
407 				1, 200);
408 	if (err) {
409 		dev_err(emc->dev, "failed to update timing: %d\n", err);
410 		return err;
411 	}
412 
413 	return 0;
414 }
415 
tegra_emc_isr(int irq,void * data)416 static irqreturn_t tegra_emc_isr(int irq, void *data)
417 {
418 	struct tegra_emc *emc = data;
419 	u32 intmask = EMC_REFRESH_OVERFLOW_INT;
420 	u32 status;
421 
422 	status = readl_relaxed(emc->regs + EMC_INTSTATUS) & intmask;
423 	if (!status)
424 		return IRQ_NONE;
425 
426 	/* notify about HW problem */
427 	if (status & EMC_REFRESH_OVERFLOW_INT)
428 		dev_err_ratelimited(emc->dev,
429 				    "refresh request overflow timeout\n");
430 
431 	/* clear interrupts */
432 	writel_relaxed(status, emc->regs + EMC_INTSTATUS);
433 
434 	return IRQ_HANDLED;
435 }
436 
emc_find_timing(struct tegra_emc * emc,unsigned long rate)437 static struct emc_timing *emc_find_timing(struct tegra_emc *emc,
438 					  unsigned long rate)
439 {
440 	struct emc_timing *timing = NULL;
441 	unsigned int i;
442 
443 	for (i = 0; i < emc->num_timings; i++) {
444 		if (emc->timings[i].rate >= rate) {
445 			timing = &emc->timings[i];
446 			break;
447 		}
448 	}
449 
450 	if (!timing) {
451 		dev_err(emc->dev, "no timing for rate %lu\n", rate);
452 		return NULL;
453 	}
454 
455 	return timing;
456 }
457 
emc_dqs_preset(struct tegra_emc * emc,struct emc_timing * timing,bool * schmitt_to_vref)458 static bool emc_dqs_preset(struct tegra_emc *emc, struct emc_timing *timing,
459 			   bool *schmitt_to_vref)
460 {
461 	bool preset = false;
462 	u32 val;
463 
464 	if (timing->data[71] & EMC_XM2DQSPADCTRL2_VREF_ENABLE) {
465 		val = readl_relaxed(emc->regs + EMC_XM2DQSPADCTRL2);
466 
467 		if (!(val & EMC_XM2DQSPADCTRL2_VREF_ENABLE)) {
468 			val |= EMC_XM2DQSPADCTRL2_VREF_ENABLE;
469 			writel_relaxed(val, emc->regs + EMC_XM2DQSPADCTRL2);
470 
471 			preset = true;
472 		}
473 	}
474 
475 	if (timing->data[78] & EMC_XM2DQSPADCTRL3_VREF_ENABLE) {
476 		val = readl_relaxed(emc->regs + EMC_XM2DQSPADCTRL3);
477 
478 		if (!(val & EMC_XM2DQSPADCTRL3_VREF_ENABLE)) {
479 			val |= EMC_XM2DQSPADCTRL3_VREF_ENABLE;
480 			writel_relaxed(val, emc->regs + EMC_XM2DQSPADCTRL3);
481 
482 			preset = true;
483 		}
484 	}
485 
486 	if (timing->data[77] & EMC_XM2QUSEPADCTRL_IVREF_ENABLE) {
487 		val = readl_relaxed(emc->regs + EMC_XM2QUSEPADCTRL);
488 
489 		if (!(val & EMC_XM2QUSEPADCTRL_IVREF_ENABLE)) {
490 			val |= EMC_XM2QUSEPADCTRL_IVREF_ENABLE;
491 			writel_relaxed(val, emc->regs + EMC_XM2QUSEPADCTRL);
492 
493 			*schmitt_to_vref = true;
494 			preset = true;
495 		}
496 	}
497 
498 	return preset;
499 }
500 
emc_prepare_mc_clk_cfg(struct tegra_emc * emc,unsigned long rate)501 static int emc_prepare_mc_clk_cfg(struct tegra_emc *emc, unsigned long rate)
502 {
503 	struct tegra_mc *mc = emc->mc;
504 	unsigned int misc0_index = 16;
505 	unsigned int i;
506 	bool same;
507 
508 	for (i = 0; i < mc->num_timings; i++) {
509 		if (mc->timings[i].rate != rate)
510 			continue;
511 
512 		if (mc->timings[i].emem_data[misc0_index] & BIT(27))
513 			same = true;
514 		else
515 			same = false;
516 
517 		return tegra20_clk_prepare_emc_mc_same_freq(emc->clk, same);
518 	}
519 
520 	return -EINVAL;
521 }
522 
emc_prepare_timing_change(struct tegra_emc * emc,unsigned long rate)523 static int emc_prepare_timing_change(struct tegra_emc *emc, unsigned long rate)
524 {
525 	struct emc_timing *timing = emc_find_timing(emc, rate);
526 	enum emc_dll_change dll_change;
527 	enum emc_dram_type dram_type;
528 	bool schmitt_to_vref = false;
529 	unsigned int pre_wait = 0;
530 	bool qrst_used = false;
531 	unsigned int dram_num;
532 	unsigned int i;
533 	u32 fbio_cfg5;
534 	u32 emc_dbg;
535 	u32 val;
536 	int err;
537 
538 	if (!timing || emc->bad_state)
539 		return -EINVAL;
540 
541 	dev_dbg(emc->dev, "%s: using timing rate %lu for requested rate %lu\n",
542 		__func__, timing->rate, rate);
543 
544 	emc->bad_state = true;
545 
546 	err = emc_prepare_mc_clk_cfg(emc, rate);
547 	if (err) {
548 		dev_err(emc->dev, "mc clock preparation failed: %d\n", err);
549 		return err;
550 	}
551 
552 	emc->vref_cal_toggle = false;
553 	emc->mc_override = mc_readl(emc->mc, MC_EMEM_ARB_OVERRIDE);
554 	emc->emc_cfg = readl_relaxed(emc->regs + EMC_CFG);
555 	emc_dbg = readl_relaxed(emc->regs + EMC_DBG);
556 
557 	if (emc->dll_on == !!(timing->emc_mode_1 & 0x1))
558 		dll_change = DLL_CHANGE_NONE;
559 	else if (timing->emc_mode_1 & 0x1)
560 		dll_change = DLL_CHANGE_ON;
561 	else
562 		dll_change = DLL_CHANGE_OFF;
563 
564 	emc->dll_on = !!(timing->emc_mode_1 & 0x1);
565 
566 	if (timing->data[80] && !readl_relaxed(emc->regs + EMC_ZCAL_INTERVAL))
567 		emc->zcal_long = true;
568 	else
569 		emc->zcal_long = false;
570 
571 	fbio_cfg5 = readl_relaxed(emc->regs + EMC_FBIO_CFG5);
572 	dram_type = fbio_cfg5 & EMC_FBIO_CFG5_DRAM_TYPE_MASK;
573 
574 	dram_num = tegra_mc_get_emem_device_count(emc->mc);
575 
576 	/* disable dynamic self-refresh */
577 	if (emc->emc_cfg & EMC_CFG_DYN_SREF_ENABLE) {
578 		emc->emc_cfg &= ~EMC_CFG_DYN_SREF_ENABLE;
579 		writel_relaxed(emc->emc_cfg, emc->regs + EMC_CFG);
580 
581 		pre_wait = 5;
582 	}
583 
584 	/* update MC arbiter settings */
585 	val = mc_readl(emc->mc, MC_EMEM_ARB_OUTSTANDING_REQ);
586 	if (!(val & MC_EMEM_ARB_OUTSTANDING_REQ_HOLDOFF_OVERRIDE) ||
587 	    ((val & MC_EMEM_ARB_OUTSTANDING_REQ_MAX_MASK) > 0x50)) {
588 
589 		val = MC_EMEM_ARB_OUTSTANDING_REQ_LIMIT_ENABLE |
590 		      MC_EMEM_ARB_OUTSTANDING_REQ_HOLDOFF_OVERRIDE | 0x50;
591 		mc_writel(emc->mc, val, MC_EMEM_ARB_OUTSTANDING_REQ);
592 		mc_writel(emc->mc, MC_TIMING_UPDATE, MC_TIMING_CONTROL);
593 	}
594 
595 	if (emc->mc_override & MC_EMEM_ARB_OVERRIDE_EACK_MASK)
596 		mc_writel(emc->mc,
597 			  emc->mc_override & ~MC_EMEM_ARB_OVERRIDE_EACK_MASK,
598 			  MC_EMEM_ARB_OVERRIDE);
599 
600 	/* check DQ/DQS VREF delay */
601 	if (emc_dqs_preset(emc, timing, &schmitt_to_vref)) {
602 		if (pre_wait < 3)
603 			pre_wait = 3;
604 	}
605 
606 	if (pre_wait) {
607 		err = emc_seq_update_timing(emc);
608 		if (err)
609 			return err;
610 
611 		udelay(pre_wait);
612 	}
613 
614 	/* disable auto-calibration if VREF mode is switching */
615 	if (timing->emc_auto_cal_interval) {
616 		val = readl_relaxed(emc->regs + EMC_XM2COMPPADCTRL);
617 		val ^= timing->data[74];
618 
619 		if (val & EMC_XM2COMPPADCTRL_VREF_CAL_ENABLE) {
620 			writel_relaxed(0, emc->regs + EMC_AUTO_CAL_INTERVAL);
621 
622 			err = readl_relaxed_poll_timeout_atomic(
623 				emc->regs + EMC_AUTO_CAL_STATUS, val,
624 				!(val & EMC_AUTO_CAL_STATUS_ACTIVE), 1, 300);
625 			if (err) {
626 				dev_err(emc->dev,
627 					"auto-cal finish timeout: %d\n", err);
628 				return err;
629 			}
630 
631 			emc->vref_cal_toggle = true;
632 		}
633 	}
634 
635 	/* program shadow registers */
636 	for (i = 0; i < ARRAY_SIZE(timing->data); i++) {
637 		/* EMC_XM2CLKPADCTRL should be programmed separately */
638 		if (i != 73)
639 			writel_relaxed(timing->data[i],
640 				       emc->regs + emc_timing_registers[i]);
641 	}
642 
643 	err = tegra_mc_write_emem_configuration(emc->mc, timing->rate);
644 	if (err)
645 		return err;
646 
647 	/* DDR3: predict MRS long wait count */
648 	if (dram_type == DRAM_TYPE_DDR3 && dll_change == DLL_CHANGE_ON) {
649 		u32 cnt = 512;
650 
651 		if (emc->zcal_long)
652 			cnt -= dram_num * 256;
653 
654 		val = timing->data[82] & EMC_MRS_WAIT_CNT_SHORT_WAIT_MASK;
655 		if (cnt < val)
656 			cnt = val;
657 
658 		val = timing->data[82] & ~EMC_MRS_WAIT_CNT_LONG_WAIT_MASK;
659 		val |= (cnt << EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT) &
660 			EMC_MRS_WAIT_CNT_LONG_WAIT_MASK;
661 
662 		writel_relaxed(val, emc->regs + EMC_MRS_WAIT_CNT);
663 	}
664 
665 	/* this read also completes the writes */
666 	val = readl_relaxed(emc->regs + EMC_SEL_DPD_CTRL);
667 
668 	if (!(val & EMC_SEL_DPD_CTRL_QUSE_DPD_ENABLE) && schmitt_to_vref) {
669 		u32 cur_mode, new_mode;
670 
671 		cur_mode = fbio_cfg5 & EMC_CFG5_QUSE_MODE_MASK;
672 		cur_mode >>= EMC_CFG5_QUSE_MODE_SHIFT;
673 
674 		new_mode = timing->data[39] & EMC_CFG5_QUSE_MODE_MASK;
675 		new_mode >>= EMC_CFG5_QUSE_MODE_SHIFT;
676 
677 		if ((cur_mode != EMC_CFG5_QUSE_MODE_PULSE_INTERN &&
678 		     cur_mode != EMC_CFG5_QUSE_MODE_INTERNAL_LPBK) ||
679 		    (new_mode != EMC_CFG5_QUSE_MODE_PULSE_INTERN &&
680 		     new_mode != EMC_CFG5_QUSE_MODE_INTERNAL_LPBK))
681 			qrst_used = true;
682 	}
683 
684 	/* flow control marker 1 */
685 	writel_relaxed(0x1, emc->regs + EMC_STALL_THEN_EXE_BEFORE_CLKCHANGE);
686 
687 	/* enable periodic reset */
688 	if (qrst_used) {
689 		writel_relaxed(emc_dbg | EMC_DBG_WRITE_MUX_ACTIVE,
690 			       emc->regs + EMC_DBG);
691 		writel_relaxed(emc->emc_cfg | EMC_CFG_PERIODIC_QRST,
692 			       emc->regs + EMC_CFG);
693 		writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
694 	}
695 
696 	/* disable auto-refresh to save time after clock change */
697 	writel_relaxed(EMC_REFCTRL_DISABLE_ALL(dram_num),
698 		       emc->regs + EMC_REFCTRL);
699 
700 	/* turn off DLL and enter self-refresh on DDR3 */
701 	if (dram_type == DRAM_TYPE_DDR3) {
702 		if (dll_change == DLL_CHANGE_OFF)
703 			writel_relaxed(timing->emc_mode_1,
704 				       emc->regs + EMC_EMRS);
705 
706 		writel_relaxed(DRAM_BROADCAST(dram_num) |
707 			       EMC_SELF_REF_CMD_ENABLED,
708 			       emc->regs + EMC_SELF_REF);
709 	}
710 
711 	/* flow control marker 2 */
712 	writel_relaxed(0x1, emc->regs + EMC_STALL_THEN_EXE_AFTER_CLKCHANGE);
713 
714 	/* enable write-active MUX, update unshadowed pad control */
715 	writel_relaxed(emc_dbg | EMC_DBG_WRITE_MUX_ACTIVE, emc->regs + EMC_DBG);
716 	writel_relaxed(timing->data[73], emc->regs + EMC_XM2CLKPADCTRL);
717 
718 	/* restore periodic QRST and disable write-active MUX */
719 	val = !!(emc->emc_cfg & EMC_CFG_PERIODIC_QRST);
720 	if (qrst_used || timing->emc_cfg_periodic_qrst != val) {
721 		if (timing->emc_cfg_periodic_qrst)
722 			emc->emc_cfg |= EMC_CFG_PERIODIC_QRST;
723 		else
724 			emc->emc_cfg &= ~EMC_CFG_PERIODIC_QRST;
725 
726 		writel_relaxed(emc->emc_cfg, emc->regs + EMC_CFG);
727 	}
728 	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
729 
730 	/* exit self-refresh on DDR3 */
731 	if (dram_type == DRAM_TYPE_DDR3)
732 		writel_relaxed(DRAM_BROADCAST(dram_num),
733 			       emc->regs + EMC_SELF_REF);
734 
735 	/* set DRAM-mode registers */
736 	if (dram_type == DRAM_TYPE_DDR3) {
737 		if (timing->emc_mode_1 != emc->emc_mode_1)
738 			writel_relaxed(timing->emc_mode_1,
739 				       emc->regs + EMC_EMRS);
740 
741 		if (timing->emc_mode_2 != emc->emc_mode_2)
742 			writel_relaxed(timing->emc_mode_2,
743 				       emc->regs + EMC_EMRS);
744 
745 		if (timing->emc_mode_reset != emc->emc_mode_reset ||
746 		    dll_change == DLL_CHANGE_ON) {
747 			val = timing->emc_mode_reset;
748 			if (dll_change == DLL_CHANGE_ON) {
749 				val |= EMC_MODE_SET_DLL_RESET;
750 				val |= EMC_MODE_SET_LONG_CNT;
751 			} else {
752 				val &= ~EMC_MODE_SET_DLL_RESET;
753 			}
754 			writel_relaxed(val, emc->regs + EMC_MRS);
755 		}
756 	} else {
757 		if (timing->emc_mode_2 != emc->emc_mode_2)
758 			writel_relaxed(timing->emc_mode_2,
759 				       emc->regs + EMC_MRW);
760 
761 		if (timing->emc_mode_1 != emc->emc_mode_1)
762 			writel_relaxed(timing->emc_mode_1,
763 				       emc->regs + EMC_MRW);
764 	}
765 
766 	emc->emc_mode_1 = timing->emc_mode_1;
767 	emc->emc_mode_2 = timing->emc_mode_2;
768 	emc->emc_mode_reset = timing->emc_mode_reset;
769 
770 	/* issue ZCAL command if turning ZCAL on */
771 	if (emc->zcal_long) {
772 		writel_relaxed(EMC_ZQ_CAL_LONG_CMD_DEV0,
773 			       emc->regs + EMC_ZQ_CAL);
774 
775 		if (dram_num > 1)
776 			writel_relaxed(EMC_ZQ_CAL_LONG_CMD_DEV1,
777 				       emc->regs + EMC_ZQ_CAL);
778 	}
779 
780 	/* flow control marker 3 */
781 	writel_relaxed(0x1, emc->regs + EMC_UNSTALL_RW_AFTER_CLKCHANGE);
782 
783 	/*
784 	 * Read and discard an arbitrary MC register (Note: EMC registers
785 	 * can't be used) to ensure the register writes are completed.
786 	 */
787 	mc_readl(emc->mc, MC_EMEM_ARB_OVERRIDE);
788 
789 	return 0;
790 }
791 
emc_complete_timing_change(struct tegra_emc * emc,unsigned long rate)792 static int emc_complete_timing_change(struct tegra_emc *emc,
793 				      unsigned long rate)
794 {
795 	struct emc_timing *timing = emc_find_timing(emc, rate);
796 	unsigned int dram_num;
797 	int err;
798 	u32 v;
799 
800 	err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_INTSTATUS, v,
801 						v & EMC_CLKCHANGE_COMPLETE_INT,
802 						1, 100);
803 	if (err) {
804 		dev_err(emc->dev, "emc-car handshake timeout: %d\n", err);
805 		return err;
806 	}
807 
808 	/* re-enable auto-refresh */
809 	dram_num = tegra_mc_get_emem_device_count(emc->mc);
810 	writel_relaxed(EMC_REFCTRL_ENABLE_ALL(dram_num),
811 		       emc->regs + EMC_REFCTRL);
812 
813 	/* restore auto-calibration */
814 	if (emc->vref_cal_toggle)
815 		writel_relaxed(timing->emc_auto_cal_interval,
816 			       emc->regs + EMC_AUTO_CAL_INTERVAL);
817 
818 	/* restore dynamic self-refresh */
819 	if (timing->emc_cfg_dyn_self_ref) {
820 		emc->emc_cfg |= EMC_CFG_DYN_SREF_ENABLE;
821 		writel_relaxed(emc->emc_cfg, emc->regs + EMC_CFG);
822 	}
823 
824 	/* set number of clocks to wait after each ZQ command */
825 	if (emc->zcal_long)
826 		writel_relaxed(timing->emc_zcal_cnt_long,
827 			       emc->regs + EMC_ZCAL_WAIT_CNT);
828 
829 	/* wait for writes to settle */
830 	udelay(2);
831 
832 	/* update restored timing */
833 	err = emc_seq_update_timing(emc);
834 	if (!err)
835 		emc->bad_state = false;
836 
837 	/* restore early ACK */
838 	mc_writel(emc->mc, emc->mc_override, MC_EMEM_ARB_OVERRIDE);
839 
840 	return err;
841 }
842 
emc_unprepare_timing_change(struct tegra_emc * emc,unsigned long rate)843 static int emc_unprepare_timing_change(struct tegra_emc *emc,
844 				       unsigned long rate)
845 {
846 	if (!emc->bad_state) {
847 		/* shouldn't ever happen in practice */
848 		dev_err(emc->dev, "timing configuration can't be reverted\n");
849 		emc->bad_state = true;
850 	}
851 
852 	return 0;
853 }
854 
emc_clk_change_notify(struct notifier_block * nb,unsigned long msg,void * data)855 static int emc_clk_change_notify(struct notifier_block *nb,
856 				 unsigned long msg, void *data)
857 {
858 	struct tegra_emc *emc = container_of(nb, struct tegra_emc, clk_nb);
859 	struct clk_notifier_data *cnd = data;
860 	int err;
861 
862 	switch (msg) {
863 	case PRE_RATE_CHANGE:
864 		/*
865 		 * Disable interrupt since read accesses are prohibited after
866 		 * stalling.
867 		 */
868 		disable_irq(emc->irq);
869 		err = emc_prepare_timing_change(emc, cnd->new_rate);
870 		enable_irq(emc->irq);
871 		break;
872 
873 	case ABORT_RATE_CHANGE:
874 		err = emc_unprepare_timing_change(emc, cnd->old_rate);
875 		break;
876 
877 	case POST_RATE_CHANGE:
878 		err = emc_complete_timing_change(emc, cnd->new_rate);
879 		break;
880 
881 	default:
882 		return NOTIFY_DONE;
883 	}
884 
885 	return notifier_from_errno(err);
886 }
887 
load_one_timing_from_dt(struct tegra_emc * emc,struct emc_timing * timing,struct device_node * node)888 static int load_one_timing_from_dt(struct tegra_emc *emc,
889 				   struct emc_timing *timing,
890 				   struct device_node *node)
891 {
892 	u32 value;
893 	int err;
894 
895 	err = of_property_read_u32(node, "clock-frequency", &value);
896 	if (err) {
897 		dev_err(emc->dev, "timing %pOF: failed to read rate: %d\n",
898 			node, err);
899 		return err;
900 	}
901 
902 	timing->rate = value;
903 
904 	err = of_property_read_u32_array(node, "nvidia,emc-configuration",
905 					 timing->data,
906 					 ARRAY_SIZE(emc_timing_registers));
907 	if (err) {
908 		dev_err(emc->dev,
909 			"timing %pOF: failed to read emc timing data: %d\n",
910 			node, err);
911 		return err;
912 	}
913 
914 #define EMC_READ_BOOL(prop, dtprop) \
915 	timing->prop = of_property_read_bool(node, dtprop);
916 
917 #define EMC_READ_U32(prop, dtprop) \
918 	err = of_property_read_u32(node, dtprop, &timing->prop); \
919 	if (err) { \
920 		dev_err(emc->dev, \
921 			"timing %pOFn: failed to read " #prop ": %d\n", \
922 			node, err); \
923 		return err; \
924 	}
925 
926 	EMC_READ_U32(emc_auto_cal_interval, "nvidia,emc-auto-cal-interval")
927 	EMC_READ_U32(emc_mode_1, "nvidia,emc-mode-1")
928 	EMC_READ_U32(emc_mode_2, "nvidia,emc-mode-2")
929 	EMC_READ_U32(emc_mode_reset, "nvidia,emc-mode-reset")
930 	EMC_READ_U32(emc_zcal_cnt_long, "nvidia,emc-zcal-cnt-long")
931 	EMC_READ_BOOL(emc_cfg_dyn_self_ref, "nvidia,emc-cfg-dyn-self-ref")
932 	EMC_READ_BOOL(emc_cfg_periodic_qrst, "nvidia,emc-cfg-periodic-qrst")
933 
934 #undef EMC_READ_U32
935 #undef EMC_READ_BOOL
936 
937 	dev_dbg(emc->dev, "%s: %pOF: rate %lu\n", __func__, node, timing->rate);
938 
939 	return 0;
940 }
941 
cmp_timings(const void * _a,const void * _b)942 static int cmp_timings(const void *_a, const void *_b)
943 {
944 	const struct emc_timing *a = _a;
945 	const struct emc_timing *b = _b;
946 
947 	if (a->rate < b->rate)
948 		return -1;
949 
950 	if (a->rate > b->rate)
951 		return 1;
952 
953 	return 0;
954 }
955 
emc_check_mc_timings(struct tegra_emc * emc)956 static int emc_check_mc_timings(struct tegra_emc *emc)
957 {
958 	struct tegra_mc *mc = emc->mc;
959 	unsigned int i;
960 
961 	if (emc->num_timings != mc->num_timings) {
962 		dev_err(emc->dev, "emc/mc timings number mismatch: %u %u\n",
963 			emc->num_timings, mc->num_timings);
964 		return -EINVAL;
965 	}
966 
967 	for (i = 0; i < mc->num_timings; i++) {
968 		if (emc->timings[i].rate != mc->timings[i].rate) {
969 			dev_err(emc->dev,
970 				"emc/mc timing rate mismatch: %lu %lu\n",
971 				emc->timings[i].rate, mc->timings[i].rate);
972 			return -EINVAL;
973 		}
974 	}
975 
976 	return 0;
977 }
978 
emc_load_timings_from_dt(struct tegra_emc * emc,struct device_node * node)979 static int emc_load_timings_from_dt(struct tegra_emc *emc,
980 				    struct device_node *node)
981 {
982 	struct device_node *child;
983 	struct emc_timing *timing;
984 	int child_count;
985 	int err;
986 
987 	child_count = of_get_child_count(node);
988 	if (!child_count) {
989 		dev_err(emc->dev, "no memory timings in: %pOF\n", node);
990 		return -EINVAL;
991 	}
992 
993 	emc->timings = devm_kcalloc(emc->dev, child_count, sizeof(*timing),
994 				    GFP_KERNEL);
995 	if (!emc->timings)
996 		return -ENOMEM;
997 
998 	emc->num_timings = child_count;
999 	timing = emc->timings;
1000 
1001 	for_each_child_of_node(node, child) {
1002 		err = load_one_timing_from_dt(emc, timing++, child);
1003 		if (err) {
1004 			of_node_put(child);
1005 			return err;
1006 		}
1007 	}
1008 
1009 	sort(emc->timings, emc->num_timings, sizeof(*timing), cmp_timings,
1010 	     NULL);
1011 
1012 	err = emc_check_mc_timings(emc);
1013 	if (err)
1014 		return err;
1015 
1016 	dev_info_once(emc->dev,
1017 		      "got %u timings for RAM code %u (min %luMHz max %luMHz)\n",
1018 		      emc->num_timings,
1019 		      tegra_read_ram_code(),
1020 		      emc->timings[0].rate / 1000000,
1021 		      emc->timings[emc->num_timings - 1].rate / 1000000);
1022 
1023 	return 0;
1024 }
1025 
emc_find_node_by_ram_code(struct tegra_emc * emc)1026 static struct device_node *emc_find_node_by_ram_code(struct tegra_emc *emc)
1027 {
1028 	struct device *dev = emc->dev;
1029 	struct device_node *np;
1030 	u32 value, ram_code;
1031 	int err;
1032 
1033 	if (emc->mrr_error) {
1034 		dev_warn(dev, "memory timings skipped due to MRR error\n");
1035 		return NULL;
1036 	}
1037 
1038 	if (of_get_child_count(dev->of_node) == 0) {
1039 		dev_info_once(dev, "device-tree doesn't have memory timings\n");
1040 		return NULL;
1041 	}
1042 
1043 	ram_code = tegra_read_ram_code();
1044 
1045 	for_each_child_of_node(dev->of_node, np) {
1046 		err = of_property_read_u32(np, "nvidia,ram-code", &value);
1047 		if (err || value != ram_code)
1048 			continue;
1049 
1050 		return np;
1051 	}
1052 
1053 	dev_err(dev, "no memory timings for RAM code %u found in device-tree\n",
1054 		ram_code);
1055 
1056 	return NULL;
1057 }
1058 
emc_read_lpddr_mode_register(struct tegra_emc * emc,unsigned int emem_dev,unsigned int register_addr,unsigned int * register_data)1059 static int emc_read_lpddr_mode_register(struct tegra_emc *emc,
1060 					unsigned int emem_dev,
1061 					unsigned int register_addr,
1062 					unsigned int *register_data)
1063 {
1064 	u32 memory_dev = emem_dev ? 1 : 2;
1065 	u32 val, mr_mask = 0xff;
1066 	int err;
1067 
1068 	/* clear data-valid interrupt status */
1069 	writel_relaxed(EMC_MRR_DIVLD_INT, emc->regs + EMC_INTSTATUS);
1070 
1071 	/* issue mode register read request */
1072 	val  = FIELD_PREP(EMC_MRR_DEV_SELECTN, memory_dev);
1073 	val |= FIELD_PREP(EMC_MRR_MRR_MA, register_addr);
1074 
1075 	writel_relaxed(val, emc->regs + EMC_MRR);
1076 
1077 	/* wait for the LPDDR2 data-valid interrupt */
1078 	err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_INTSTATUS, val,
1079 						val & EMC_MRR_DIVLD_INT,
1080 						1, 100);
1081 	if (err) {
1082 		dev_err(emc->dev, "mode register %u read failed: %d\n",
1083 			register_addr, err);
1084 		emc->mrr_error = true;
1085 		return err;
1086 	}
1087 
1088 	/* read out mode register data */
1089 	val = readl_relaxed(emc->regs + EMC_MRR);
1090 	*register_data = FIELD_GET(EMC_MRR_MRR_DATA, val) & mr_mask;
1091 
1092 	return 0;
1093 }
1094 
emc_read_lpddr_sdram_info(struct tegra_emc * emc,unsigned int emem_dev)1095 static void emc_read_lpddr_sdram_info(struct tegra_emc *emc,
1096 				      unsigned int emem_dev)
1097 {
1098 	union lpddr2_basic_config4 basic_conf4;
1099 	unsigned int manufacturer_id;
1100 	unsigned int revision_id1;
1101 	unsigned int revision_id2;
1102 
1103 	/* these registers are standard for all LPDDR JEDEC memory chips */
1104 	emc_read_lpddr_mode_register(emc, emem_dev, 5, &manufacturer_id);
1105 	emc_read_lpddr_mode_register(emc, emem_dev, 6, &revision_id1);
1106 	emc_read_lpddr_mode_register(emc, emem_dev, 7, &revision_id2);
1107 	emc_read_lpddr_mode_register(emc, emem_dev, 8, &basic_conf4.value);
1108 
1109 	dev_info(emc->dev, "SDRAM[dev%u]: manufacturer: 0x%x (%s) rev1: 0x%x rev2: 0x%x prefetch: S%u density: %uMbit iowidth: %ubit\n",
1110 		 emem_dev, manufacturer_id,
1111 		 lpddr2_jedec_manufacturer(manufacturer_id),
1112 		 revision_id1, revision_id2,
1113 		 4 >> basic_conf4.arch_type,
1114 		 64 << basic_conf4.density,
1115 		 32 >> basic_conf4.io_width);
1116 }
1117 
emc_setup_hw(struct tegra_emc * emc)1118 static int emc_setup_hw(struct tegra_emc *emc)
1119 {
1120 	u32 fbio_cfg5, emc_cfg, emc_dbg, emc_adr_cfg;
1121 	u32 intmask = EMC_REFRESH_OVERFLOW_INT;
1122 	static bool print_sdram_info_once;
1123 	enum emc_dram_type dram_type;
1124 	const char *dram_type_str;
1125 	unsigned int emem_numdev;
1126 
1127 	fbio_cfg5 = readl_relaxed(emc->regs + EMC_FBIO_CFG5);
1128 	dram_type = fbio_cfg5 & EMC_FBIO_CFG5_DRAM_TYPE_MASK;
1129 
1130 	emc_cfg = readl_relaxed(emc->regs + EMC_CFG_2);
1131 
1132 	/* enable EMC and CAR to handshake on PLL divider/source changes */
1133 	emc_cfg |= EMC_CLKCHANGE_REQ_ENABLE;
1134 
1135 	/* configure clock change mode accordingly to DRAM type */
1136 	switch (dram_type) {
1137 	case DRAM_TYPE_LPDDR2:
1138 		emc_cfg |= EMC_CLKCHANGE_PD_ENABLE;
1139 		emc_cfg &= ~EMC_CLKCHANGE_SR_ENABLE;
1140 		break;
1141 
1142 	default:
1143 		emc_cfg &= ~EMC_CLKCHANGE_SR_ENABLE;
1144 		emc_cfg &= ~EMC_CLKCHANGE_PD_ENABLE;
1145 		break;
1146 	}
1147 
1148 	writel_relaxed(emc_cfg, emc->regs + EMC_CFG_2);
1149 
1150 	/* initialize interrupt */
1151 	writel_relaxed(intmask, emc->regs + EMC_INTMASK);
1152 	writel_relaxed(0xffffffff, emc->regs + EMC_INTSTATUS);
1153 
1154 	/* ensure that unwanted debug features are disabled */
1155 	emc_dbg = readl_relaxed(emc->regs + EMC_DBG);
1156 	emc_dbg |= EMC_DBG_CFG_PRIORITY;
1157 	emc_dbg &= ~EMC_DBG_READ_MUX_ASSEMBLY;
1158 	emc_dbg &= ~EMC_DBG_WRITE_MUX_ACTIVE;
1159 	emc_dbg &= ~EMC_DBG_FORCE_UPDATE;
1160 	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
1161 
1162 	switch (dram_type) {
1163 	case DRAM_TYPE_DDR1:
1164 		dram_type_str = "DDR1";
1165 		break;
1166 	case DRAM_TYPE_LPDDR2:
1167 		dram_type_str = "LPDDR2";
1168 		break;
1169 	case DRAM_TYPE_DDR2:
1170 		dram_type_str = "DDR2";
1171 		break;
1172 	case DRAM_TYPE_DDR3:
1173 		dram_type_str = "DDR3";
1174 		break;
1175 	}
1176 
1177 	emc_adr_cfg = readl_relaxed(emc->regs + EMC_ADR_CFG);
1178 	emem_numdev = FIELD_GET(EMC_ADR_CFG_EMEM_NUMDEV, emc_adr_cfg) + 1;
1179 
1180 	dev_info_once(emc->dev, "%u %s %s attached\n", emem_numdev,
1181 		      dram_type_str, emem_numdev == 2 ? "devices" : "device");
1182 
1183 	if (dram_type == DRAM_TYPE_LPDDR2 && !print_sdram_info_once) {
1184 		while (emem_numdev--)
1185 			emc_read_lpddr_sdram_info(emc, emem_numdev);
1186 
1187 		print_sdram_info_once = true;
1188 	}
1189 
1190 	return 0;
1191 }
1192 
emc_round_rate(unsigned long rate,unsigned long min_rate,unsigned long max_rate,void * arg)1193 static long emc_round_rate(unsigned long rate,
1194 			   unsigned long min_rate,
1195 			   unsigned long max_rate,
1196 			   void *arg)
1197 {
1198 	struct emc_timing *timing = NULL;
1199 	struct tegra_emc *emc = arg;
1200 	unsigned int i;
1201 
1202 	if (!emc->num_timings)
1203 		return clk_get_rate(emc->clk);
1204 
1205 	min_rate = min(min_rate, emc->timings[emc->num_timings - 1].rate);
1206 
1207 	for (i = 0; i < emc->num_timings; i++) {
1208 		if (emc->timings[i].rate < rate && i != emc->num_timings - 1)
1209 			continue;
1210 
1211 		if (emc->timings[i].rate > max_rate) {
1212 			i = max(i, 1u) - 1;
1213 
1214 			if (emc->timings[i].rate < min_rate)
1215 				break;
1216 		}
1217 
1218 		if (emc->timings[i].rate < min_rate)
1219 			continue;
1220 
1221 		timing = &emc->timings[i];
1222 		break;
1223 	}
1224 
1225 	if (!timing) {
1226 		dev_err(emc->dev, "no timing for rate %lu min %lu max %lu\n",
1227 			rate, min_rate, max_rate);
1228 		return -EINVAL;
1229 	}
1230 
1231 	return timing->rate;
1232 }
1233 
tegra_emc_rate_requests_init(struct tegra_emc * emc)1234 static void tegra_emc_rate_requests_init(struct tegra_emc *emc)
1235 {
1236 	unsigned int i;
1237 
1238 	for (i = 0; i < EMC_RATE_TYPE_MAX; i++) {
1239 		emc->requested_rate[i].min_rate = 0;
1240 		emc->requested_rate[i].max_rate = ULONG_MAX;
1241 	}
1242 }
1243 
emc_request_rate(struct tegra_emc * emc,unsigned long new_min_rate,unsigned long new_max_rate,enum emc_rate_request_type type)1244 static int emc_request_rate(struct tegra_emc *emc,
1245 			    unsigned long new_min_rate,
1246 			    unsigned long new_max_rate,
1247 			    enum emc_rate_request_type type)
1248 {
1249 	struct emc_rate_request *req = emc->requested_rate;
1250 	unsigned long min_rate = 0, max_rate = ULONG_MAX;
1251 	unsigned int i;
1252 	int err;
1253 
1254 	/* select minimum and maximum rates among the requested rates */
1255 	for (i = 0; i < EMC_RATE_TYPE_MAX; i++, req++) {
1256 		if (i == type) {
1257 			min_rate = max(new_min_rate, min_rate);
1258 			max_rate = min(new_max_rate, max_rate);
1259 		} else {
1260 			min_rate = max(req->min_rate, min_rate);
1261 			max_rate = min(req->max_rate, max_rate);
1262 		}
1263 	}
1264 
1265 	if (min_rate > max_rate) {
1266 		dev_err_ratelimited(emc->dev, "%s: type %u: out of range: %lu %lu\n",
1267 				    __func__, type, min_rate, max_rate);
1268 		return -ERANGE;
1269 	}
1270 
1271 	/*
1272 	 * EMC rate-changes should go via OPP API because it manages voltage
1273 	 * changes.
1274 	 */
1275 	err = dev_pm_opp_set_rate(emc->dev, min_rate);
1276 	if (err)
1277 		return err;
1278 
1279 	emc->requested_rate[type].min_rate = new_min_rate;
1280 	emc->requested_rate[type].max_rate = new_max_rate;
1281 
1282 	return 0;
1283 }
1284 
emc_set_min_rate(struct tegra_emc * emc,unsigned long rate,enum emc_rate_request_type type)1285 static int emc_set_min_rate(struct tegra_emc *emc, unsigned long rate,
1286 			    enum emc_rate_request_type type)
1287 {
1288 	struct emc_rate_request *req = &emc->requested_rate[type];
1289 	int ret;
1290 
1291 	mutex_lock(&emc->rate_lock);
1292 	ret = emc_request_rate(emc, rate, req->max_rate, type);
1293 	mutex_unlock(&emc->rate_lock);
1294 
1295 	return ret;
1296 }
1297 
emc_set_max_rate(struct tegra_emc * emc,unsigned long rate,enum emc_rate_request_type type)1298 static int emc_set_max_rate(struct tegra_emc *emc, unsigned long rate,
1299 			    enum emc_rate_request_type type)
1300 {
1301 	struct emc_rate_request *req = &emc->requested_rate[type];
1302 	int ret;
1303 
1304 	mutex_lock(&emc->rate_lock);
1305 	ret = emc_request_rate(emc, req->min_rate, rate, type);
1306 	mutex_unlock(&emc->rate_lock);
1307 
1308 	return ret;
1309 }
1310 
1311 /*
1312  * debugfs interface
1313  *
1314  * The memory controller driver exposes some files in debugfs that can be used
1315  * to control the EMC frequency. The top-level directory can be found here:
1316  *
1317  *   /sys/kernel/debug/emc
1318  *
1319  * It contains the following files:
1320  *
1321  *   - available_rates: This file contains a list of valid, space-separated
1322  *     EMC frequencies.
1323  *
1324  *   - min_rate: Writing a value to this file sets the given frequency as the
1325  *       floor of the permitted range. If this is higher than the currently
1326  *       configured EMC frequency, this will cause the frequency to be
1327  *       increased so that it stays within the valid range.
1328  *
1329  *   - max_rate: Similarily to the min_rate file, writing a value to this file
1330  *       sets the given frequency as the ceiling of the permitted range. If
1331  *       the value is lower than the currently configured EMC frequency, this
1332  *       will cause the frequency to be decreased so that it stays within the
1333  *       valid range.
1334  */
1335 
tegra_emc_validate_rate(struct tegra_emc * emc,unsigned long rate)1336 static bool tegra_emc_validate_rate(struct tegra_emc *emc, unsigned long rate)
1337 {
1338 	unsigned int i;
1339 
1340 	for (i = 0; i < emc->num_timings; i++)
1341 		if (rate == emc->timings[i].rate)
1342 			return true;
1343 
1344 	return false;
1345 }
1346 
tegra_emc_debug_available_rates_show(struct seq_file * s,void * data)1347 static int tegra_emc_debug_available_rates_show(struct seq_file *s, void *data)
1348 {
1349 	struct tegra_emc *emc = s->private;
1350 	const char *prefix = "";
1351 	unsigned int i;
1352 
1353 	for (i = 0; i < emc->num_timings; i++) {
1354 		seq_printf(s, "%s%lu", prefix, emc->timings[i].rate);
1355 		prefix = " ";
1356 	}
1357 
1358 	seq_puts(s, "\n");
1359 
1360 	return 0;
1361 }
1362 DEFINE_SHOW_ATTRIBUTE(tegra_emc_debug_available_rates);
1363 
tegra_emc_debug_min_rate_get(void * data,u64 * rate)1364 static int tegra_emc_debug_min_rate_get(void *data, u64 *rate)
1365 {
1366 	struct tegra_emc *emc = data;
1367 
1368 	*rate = emc->debugfs.min_rate;
1369 
1370 	return 0;
1371 }
1372 
tegra_emc_debug_min_rate_set(void * data,u64 rate)1373 static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
1374 {
1375 	struct tegra_emc *emc = data;
1376 	int err;
1377 
1378 	if (!tegra_emc_validate_rate(emc, rate))
1379 		return -EINVAL;
1380 
1381 	err = emc_set_min_rate(emc, rate, EMC_RATE_DEBUG);
1382 	if (err < 0)
1383 		return err;
1384 
1385 	emc->debugfs.min_rate = rate;
1386 
1387 	return 0;
1388 }
1389 
1390 DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
1391 			tegra_emc_debug_min_rate_get,
1392 			tegra_emc_debug_min_rate_set, "%llu\n");
1393 
tegra_emc_debug_max_rate_get(void * data,u64 * rate)1394 static int tegra_emc_debug_max_rate_get(void *data, u64 *rate)
1395 {
1396 	struct tegra_emc *emc = data;
1397 
1398 	*rate = emc->debugfs.max_rate;
1399 
1400 	return 0;
1401 }
1402 
tegra_emc_debug_max_rate_set(void * data,u64 rate)1403 static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
1404 {
1405 	struct tegra_emc *emc = data;
1406 	int err;
1407 
1408 	if (!tegra_emc_validate_rate(emc, rate))
1409 		return -EINVAL;
1410 
1411 	err = emc_set_max_rate(emc, rate, EMC_RATE_DEBUG);
1412 	if (err < 0)
1413 		return err;
1414 
1415 	emc->debugfs.max_rate = rate;
1416 
1417 	return 0;
1418 }
1419 
1420 DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
1421 			tegra_emc_debug_max_rate_get,
1422 			tegra_emc_debug_max_rate_set, "%llu\n");
1423 
tegra_emc_debugfs_init(struct tegra_emc * emc)1424 static void tegra_emc_debugfs_init(struct tegra_emc *emc)
1425 {
1426 	struct device *dev = emc->dev;
1427 	unsigned int i;
1428 	int err;
1429 
1430 	emc->debugfs.min_rate = ULONG_MAX;
1431 	emc->debugfs.max_rate = 0;
1432 
1433 	for (i = 0; i < emc->num_timings; i++) {
1434 		if (emc->timings[i].rate < emc->debugfs.min_rate)
1435 			emc->debugfs.min_rate = emc->timings[i].rate;
1436 
1437 		if (emc->timings[i].rate > emc->debugfs.max_rate)
1438 			emc->debugfs.max_rate = emc->timings[i].rate;
1439 	}
1440 
1441 	if (!emc->num_timings) {
1442 		emc->debugfs.min_rate = clk_get_rate(emc->clk);
1443 		emc->debugfs.max_rate = emc->debugfs.min_rate;
1444 	}
1445 
1446 	err = clk_set_rate_range(emc->clk, emc->debugfs.min_rate,
1447 				 emc->debugfs.max_rate);
1448 	if (err < 0) {
1449 		dev_err(dev, "failed to set rate range [%lu-%lu] for %pC\n",
1450 			emc->debugfs.min_rate, emc->debugfs.max_rate,
1451 			emc->clk);
1452 	}
1453 
1454 	emc->debugfs.root = debugfs_create_dir("emc", NULL);
1455 
1456 	debugfs_create_file("available_rates", 0444, emc->debugfs.root,
1457 			    emc, &tegra_emc_debug_available_rates_fops);
1458 	debugfs_create_file("min_rate", 0644, emc->debugfs.root,
1459 			    emc, &tegra_emc_debug_min_rate_fops);
1460 	debugfs_create_file("max_rate", 0644, emc->debugfs.root,
1461 			    emc, &tegra_emc_debug_max_rate_fops);
1462 }
1463 
1464 static inline struct tegra_emc *
to_tegra_emc_provider(struct icc_provider * provider)1465 to_tegra_emc_provider(struct icc_provider *provider)
1466 {
1467 	return container_of(provider, struct tegra_emc, provider);
1468 }
1469 
1470 static struct icc_node_data *
emc_of_icc_xlate_extended(struct of_phandle_args * spec,void * data)1471 emc_of_icc_xlate_extended(struct of_phandle_args *spec, void *data)
1472 {
1473 	struct icc_provider *provider = data;
1474 	struct icc_node_data *ndata;
1475 	struct icc_node *node;
1476 
1477 	/* External Memory is the only possible ICC route */
1478 	list_for_each_entry(node, &provider->nodes, node_list) {
1479 		if (node->id != TEGRA_ICC_EMEM)
1480 			continue;
1481 
1482 		ndata = kzalloc(sizeof(*ndata), GFP_KERNEL);
1483 		if (!ndata)
1484 			return ERR_PTR(-ENOMEM);
1485 
1486 		/*
1487 		 * SRC and DST nodes should have matching TAG in order to have
1488 		 * it set by default for a requested path.
1489 		 */
1490 		ndata->tag = TEGRA_MC_ICC_TAG_ISO;
1491 		ndata->node = node;
1492 
1493 		return ndata;
1494 	}
1495 
1496 	return ERR_PTR(-EPROBE_DEFER);
1497 }
1498 
emc_icc_set(struct icc_node * src,struct icc_node * dst)1499 static int emc_icc_set(struct icc_node *src, struct icc_node *dst)
1500 {
1501 	struct tegra_emc *emc = to_tegra_emc_provider(dst->provider);
1502 	unsigned long long peak_bw = icc_units_to_bps(dst->peak_bw);
1503 	unsigned long long avg_bw = icc_units_to_bps(dst->avg_bw);
1504 	unsigned long long rate = max(avg_bw, peak_bw);
1505 	const unsigned int dram_data_bus_width_bytes = 4;
1506 	const unsigned int ddr = 2;
1507 	int err;
1508 
1509 	/*
1510 	 * Tegra30 EMC runs on a clock rate of SDRAM bus.  This means that
1511 	 * EMC clock rate is twice smaller than the peak data rate because
1512 	 * data is sampled on both EMC clock edges.
1513 	 */
1514 	do_div(rate, ddr * dram_data_bus_width_bytes);
1515 	rate = min_t(u64, rate, U32_MAX);
1516 
1517 	err = emc_set_min_rate(emc, rate, EMC_RATE_ICC);
1518 	if (err)
1519 		return err;
1520 
1521 	return 0;
1522 }
1523 
tegra_emc_interconnect_init(struct tegra_emc * emc)1524 static int tegra_emc_interconnect_init(struct tegra_emc *emc)
1525 {
1526 	const struct tegra_mc_soc *soc = emc->mc->soc;
1527 	struct icc_node *node;
1528 	int err;
1529 
1530 	emc->provider.dev = emc->dev;
1531 	emc->provider.set = emc_icc_set;
1532 	emc->provider.data = &emc->provider;
1533 	emc->provider.aggregate = soc->icc_ops->aggregate;
1534 	emc->provider.xlate_extended = emc_of_icc_xlate_extended;
1535 
1536 	icc_provider_init(&emc->provider);
1537 
1538 	/* create External Memory Controller node */
1539 	node = icc_node_create(TEGRA_ICC_EMC);
1540 	if (IS_ERR(node)) {
1541 		err = PTR_ERR(node);
1542 		goto err_msg;
1543 	}
1544 
1545 	node->name = "External Memory Controller";
1546 	icc_node_add(node, &emc->provider);
1547 
1548 	/* link External Memory Controller to External Memory (DRAM) */
1549 	err = icc_link_create(node, TEGRA_ICC_EMEM);
1550 	if (err)
1551 		goto remove_nodes;
1552 
1553 	/* create External Memory node */
1554 	node = icc_node_create(TEGRA_ICC_EMEM);
1555 	if (IS_ERR(node)) {
1556 		err = PTR_ERR(node);
1557 		goto remove_nodes;
1558 	}
1559 
1560 	node->name = "External Memory (DRAM)";
1561 	icc_node_add(node, &emc->provider);
1562 
1563 	err = icc_provider_register(&emc->provider);
1564 	if (err)
1565 		goto remove_nodes;
1566 
1567 	return 0;
1568 
1569 remove_nodes:
1570 	icc_nodes_remove(&emc->provider);
1571 err_msg:
1572 	dev_err(emc->dev, "failed to initialize ICC: %d\n", err);
1573 
1574 	return err;
1575 }
1576 
devm_tegra_emc_unset_callback(void * data)1577 static void devm_tegra_emc_unset_callback(void *data)
1578 {
1579 	tegra20_clk_set_emc_round_callback(NULL, NULL);
1580 }
1581 
devm_tegra_emc_unreg_clk_notifier(void * data)1582 static void devm_tegra_emc_unreg_clk_notifier(void *data)
1583 {
1584 	struct tegra_emc *emc = data;
1585 
1586 	clk_notifier_unregister(emc->clk, &emc->clk_nb);
1587 }
1588 
tegra_emc_init_clk(struct tegra_emc * emc)1589 static int tegra_emc_init_clk(struct tegra_emc *emc)
1590 {
1591 	int err;
1592 
1593 	tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
1594 
1595 	err = devm_add_action_or_reset(emc->dev, devm_tegra_emc_unset_callback,
1596 				       NULL);
1597 	if (err)
1598 		return err;
1599 
1600 	emc->clk = devm_clk_get(emc->dev, NULL);
1601 	if (IS_ERR(emc->clk)) {
1602 		dev_err(emc->dev, "failed to get EMC clock: %pe\n", emc->clk);
1603 		return PTR_ERR(emc->clk);
1604 	}
1605 
1606 	err = clk_notifier_register(emc->clk, &emc->clk_nb);
1607 	if (err) {
1608 		dev_err(emc->dev, "failed to register clk notifier: %d\n", err);
1609 		return err;
1610 	}
1611 
1612 	err = devm_add_action_or_reset(emc->dev,
1613 				       devm_tegra_emc_unreg_clk_notifier, emc);
1614 	if (err)
1615 		return err;
1616 
1617 	return 0;
1618 }
1619 
tegra_emc_probe(struct platform_device * pdev)1620 static int tegra_emc_probe(struct platform_device *pdev)
1621 {
1622 	struct tegra_core_opp_params opp_params = {};
1623 	struct device_node *np;
1624 	struct tegra_emc *emc;
1625 	int err;
1626 
1627 	emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
1628 	if (!emc)
1629 		return -ENOMEM;
1630 
1631 	emc->mc = devm_tegra_memory_controller_get(&pdev->dev);
1632 	if (IS_ERR(emc->mc))
1633 		return PTR_ERR(emc->mc);
1634 
1635 	mutex_init(&emc->rate_lock);
1636 	emc->clk_nb.notifier_call = emc_clk_change_notify;
1637 	emc->dev = &pdev->dev;
1638 
1639 	emc->regs = devm_platform_ioremap_resource(pdev, 0);
1640 	if (IS_ERR(emc->regs))
1641 		return PTR_ERR(emc->regs);
1642 
1643 	err = emc_setup_hw(emc);
1644 	if (err)
1645 		return err;
1646 
1647 	np = emc_find_node_by_ram_code(emc);
1648 	if (np) {
1649 		err = emc_load_timings_from_dt(emc, np);
1650 		of_node_put(np);
1651 		if (err)
1652 			return err;
1653 	}
1654 
1655 	err = platform_get_irq(pdev, 0);
1656 	if (err < 0)
1657 		return err;
1658 
1659 	emc->irq = err;
1660 
1661 	err = devm_request_irq(&pdev->dev, emc->irq, tegra_emc_isr, 0,
1662 			       dev_name(&pdev->dev), emc);
1663 	if (err) {
1664 		dev_err(&pdev->dev, "failed to request irq: %d\n", err);
1665 		return err;
1666 	}
1667 
1668 	err = tegra_emc_init_clk(emc);
1669 	if (err)
1670 		return err;
1671 
1672 	opp_params.init_state = true;
1673 
1674 	err = devm_tegra_core_dev_init_opp_table(&pdev->dev, &opp_params);
1675 	if (err)
1676 		return err;
1677 
1678 	platform_set_drvdata(pdev, emc);
1679 	tegra_emc_rate_requests_init(emc);
1680 	tegra_emc_debugfs_init(emc);
1681 	tegra_emc_interconnect_init(emc);
1682 
1683 	/*
1684 	 * Don't allow the kernel module to be unloaded. Unloading adds some
1685 	 * extra complexity which doesn't really worth the effort in a case of
1686 	 * this driver.
1687 	 */
1688 	try_module_get(THIS_MODULE);
1689 
1690 	return 0;
1691 }
1692 
tegra_emc_suspend(struct device * dev)1693 static int tegra_emc_suspend(struct device *dev)
1694 {
1695 	struct tegra_emc *emc = dev_get_drvdata(dev);
1696 	int err;
1697 
1698 	/* take exclusive control over the clock's rate */
1699 	err = clk_rate_exclusive_get(emc->clk);
1700 	if (err) {
1701 		dev_err(emc->dev, "failed to acquire clk: %d\n", err);
1702 		return err;
1703 	}
1704 
1705 	/* suspending in a bad state will hang machine */
1706 	if (WARN(emc->bad_state, "hardware in a bad state\n"))
1707 		return -EINVAL;
1708 
1709 	emc->bad_state = true;
1710 
1711 	return 0;
1712 }
1713 
tegra_emc_resume(struct device * dev)1714 static int tegra_emc_resume(struct device *dev)
1715 {
1716 	struct tegra_emc *emc = dev_get_drvdata(dev);
1717 
1718 	emc_setup_hw(emc);
1719 	emc->bad_state = false;
1720 
1721 	clk_rate_exclusive_put(emc->clk);
1722 
1723 	return 0;
1724 }
1725 
1726 static const struct dev_pm_ops tegra_emc_pm_ops = {
1727 	.suspend = tegra_emc_suspend,
1728 	.resume = tegra_emc_resume,
1729 };
1730 
1731 static const struct of_device_id tegra_emc_of_match[] = {
1732 	{ .compatible = "nvidia,tegra30-emc", },
1733 	{},
1734 };
1735 MODULE_DEVICE_TABLE(of, tegra_emc_of_match);
1736 
1737 static struct platform_driver tegra_emc_driver = {
1738 	.probe = tegra_emc_probe,
1739 	.driver = {
1740 		.name = "tegra30-emc",
1741 		.of_match_table = tegra_emc_of_match,
1742 		.pm = &tegra_emc_pm_ops,
1743 		.suppress_bind_attrs = true,
1744 		.sync_state = icc_sync_state,
1745 	},
1746 };
1747 module_platform_driver(tegra_emc_driver);
1748 
1749 MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
1750 MODULE_DESCRIPTION("NVIDIA Tegra30 EMC driver");
1751 MODULE_LICENSE("GPL v2");
1752