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/clk.h>
13 #include <linux/clk/tegra.h>
14 #include <linux/completion.h>
15 #include <linux/delay.h>
16 #include <linux/err.h>
17 #include <linux/interrupt.h>
18 #include <linux/io.h>
19 #include <linux/iopoll.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/of_platform.h>
23 #include <linux/platform_device.h>
24 #include <linux/sort.h>
25 #include <linux/types.h>
26 
27 #include <soc/tegra/fuse.h>
28 
29 #include "mc.h"
30 
31 #define EMC_INTSTATUS				0x000
32 #define EMC_INTMASK				0x004
33 #define EMC_DBG					0x008
34 #define EMC_CFG					0x00c
35 #define EMC_REFCTRL				0x020
36 #define EMC_TIMING_CONTROL			0x028
37 #define EMC_RC					0x02c
38 #define EMC_RFC					0x030
39 #define EMC_RAS					0x034
40 #define EMC_RP					0x038
41 #define EMC_R2W					0x03c
42 #define EMC_W2R					0x040
43 #define EMC_R2P					0x044
44 #define EMC_W2P					0x048
45 #define EMC_RD_RCD				0x04c
46 #define EMC_WR_RCD				0x050
47 #define EMC_RRD					0x054
48 #define EMC_REXT				0x058
49 #define EMC_WDV					0x05c
50 #define EMC_QUSE				0x060
51 #define EMC_QRST				0x064
52 #define EMC_QSAFE				0x068
53 #define EMC_RDV					0x06c
54 #define EMC_REFRESH				0x070
55 #define EMC_BURST_REFRESH_NUM			0x074
56 #define EMC_PDEX2WR				0x078
57 #define EMC_PDEX2RD				0x07c
58 #define EMC_PCHG2PDEN				0x080
59 #define EMC_ACT2PDEN				0x084
60 #define EMC_AR2PDEN				0x088
61 #define EMC_RW2PDEN				0x08c
62 #define EMC_TXSR				0x090
63 #define EMC_TCKE				0x094
64 #define EMC_TFAW				0x098
65 #define EMC_TRPAB				0x09c
66 #define EMC_TCLKSTABLE				0x0a0
67 #define EMC_TCLKSTOP				0x0a4
68 #define EMC_TREFBW				0x0a8
69 #define EMC_QUSE_EXTRA				0x0ac
70 #define EMC_ODT_WRITE				0x0b0
71 #define EMC_ODT_READ				0x0b4
72 #define EMC_WEXT				0x0b8
73 #define EMC_CTT					0x0bc
74 #define EMC_MRS_WAIT_CNT			0x0c8
75 #define EMC_MRS					0x0cc
76 #define EMC_EMRS				0x0d0
77 #define EMC_SELF_REF				0x0e0
78 #define EMC_MRW					0x0e8
79 #define EMC_XM2DQSPADCTRL3			0x0f8
80 #define EMC_FBIO_SPARE				0x100
81 #define EMC_FBIO_CFG5				0x104
82 #define EMC_FBIO_CFG6				0x114
83 #define EMC_CFG_RSV				0x120
84 #define EMC_AUTO_CAL_CONFIG			0x2a4
85 #define EMC_AUTO_CAL_INTERVAL			0x2a8
86 #define EMC_AUTO_CAL_STATUS			0x2ac
87 #define EMC_STATUS				0x2b4
88 #define EMC_CFG_2				0x2b8
89 #define EMC_CFG_DIG_DLL				0x2bc
90 #define EMC_CFG_DIG_DLL_PERIOD			0x2c0
91 #define EMC_CTT_DURATION			0x2d8
92 #define EMC_CTT_TERM_CTRL			0x2dc
93 #define EMC_ZCAL_INTERVAL			0x2e0
94 #define EMC_ZCAL_WAIT_CNT			0x2e4
95 #define EMC_ZQ_CAL				0x2ec
96 #define EMC_XM2CMDPADCTRL			0x2f0
97 #define EMC_XM2DQSPADCTRL2			0x2fc
98 #define EMC_XM2DQPADCTRL2			0x304
99 #define EMC_XM2CLKPADCTRL			0x308
100 #define EMC_XM2COMPPADCTRL			0x30c
101 #define EMC_XM2VTTGENPADCTRL			0x310
102 #define EMC_XM2VTTGENPADCTRL2			0x314
103 #define EMC_XM2QUSEPADCTRL			0x318
104 #define EMC_DLL_XFORM_DQS0			0x328
105 #define EMC_DLL_XFORM_DQS1			0x32c
106 #define EMC_DLL_XFORM_DQS2			0x330
107 #define EMC_DLL_XFORM_DQS3			0x334
108 #define EMC_DLL_XFORM_DQS4			0x338
109 #define EMC_DLL_XFORM_DQS5			0x33c
110 #define EMC_DLL_XFORM_DQS6			0x340
111 #define EMC_DLL_XFORM_DQS7			0x344
112 #define EMC_DLL_XFORM_QUSE0			0x348
113 #define EMC_DLL_XFORM_QUSE1			0x34c
114 #define EMC_DLL_XFORM_QUSE2			0x350
115 #define EMC_DLL_XFORM_QUSE3			0x354
116 #define EMC_DLL_XFORM_QUSE4			0x358
117 #define EMC_DLL_XFORM_QUSE5			0x35c
118 #define EMC_DLL_XFORM_QUSE6			0x360
119 #define EMC_DLL_XFORM_QUSE7			0x364
120 #define EMC_DLL_XFORM_DQ0			0x368
121 #define EMC_DLL_XFORM_DQ1			0x36c
122 #define EMC_DLL_XFORM_DQ2			0x370
123 #define EMC_DLL_XFORM_DQ3			0x374
124 #define EMC_DLI_TRIM_TXDQS0			0x3a8
125 #define EMC_DLI_TRIM_TXDQS1			0x3ac
126 #define EMC_DLI_TRIM_TXDQS2			0x3b0
127 #define EMC_DLI_TRIM_TXDQS3			0x3b4
128 #define EMC_DLI_TRIM_TXDQS4			0x3b8
129 #define EMC_DLI_TRIM_TXDQS5			0x3bc
130 #define EMC_DLI_TRIM_TXDQS6			0x3c0
131 #define EMC_DLI_TRIM_TXDQS7			0x3c4
132 #define EMC_STALL_THEN_EXE_BEFORE_CLKCHANGE	0x3c8
133 #define EMC_STALL_THEN_EXE_AFTER_CLKCHANGE	0x3cc
134 #define EMC_UNSTALL_RW_AFTER_CLKCHANGE		0x3d0
135 #define EMC_SEL_DPD_CTRL			0x3d8
136 #define EMC_PRE_REFRESH_REQ_CNT			0x3dc
137 #define EMC_DYN_SELF_REF_CONTROL		0x3e0
138 #define EMC_TXSRDLL				0x3e4
139 
140 #define EMC_STATUS_TIMING_UPDATE_STALLED	BIT(23)
141 
142 #define EMC_MODE_SET_DLL_RESET			BIT(8)
143 #define EMC_MODE_SET_LONG_CNT			BIT(26)
144 
145 #define EMC_SELF_REF_CMD_ENABLED		BIT(0)
146 
147 #define DRAM_DEV_SEL_ALL			(0 << 30)
148 #define DRAM_DEV_SEL_0				(2 << 30)
149 #define DRAM_DEV_SEL_1				(1 << 30)
150 #define DRAM_BROADCAST(num) \
151 	((num) > 1 ? DRAM_DEV_SEL_ALL : DRAM_DEV_SEL_0)
152 
153 #define EMC_ZQ_CAL_CMD				BIT(0)
154 #define EMC_ZQ_CAL_LONG				BIT(4)
155 #define EMC_ZQ_CAL_LONG_CMD_DEV0 \
156 	(DRAM_DEV_SEL_0 | EMC_ZQ_CAL_LONG | EMC_ZQ_CAL_CMD)
157 #define EMC_ZQ_CAL_LONG_CMD_DEV1 \
158 	(DRAM_DEV_SEL_1 | EMC_ZQ_CAL_LONG | EMC_ZQ_CAL_CMD)
159 
160 #define EMC_DBG_READ_MUX_ASSEMBLY		BIT(0)
161 #define EMC_DBG_WRITE_MUX_ACTIVE		BIT(1)
162 #define EMC_DBG_FORCE_UPDATE			BIT(2)
163 #define EMC_DBG_CFG_PRIORITY			BIT(24)
164 
165 #define EMC_CFG5_QUSE_MODE_SHIFT		13
166 #define EMC_CFG5_QUSE_MODE_MASK			(7 << EMC_CFG5_QUSE_MODE_SHIFT)
167 
168 #define EMC_CFG5_QUSE_MODE_INTERNAL_LPBK	2
169 #define EMC_CFG5_QUSE_MODE_PULSE_INTERN		3
170 
171 #define EMC_SEL_DPD_CTRL_QUSE_DPD_ENABLE	BIT(9)
172 
173 #define EMC_XM2COMPPADCTRL_VREF_CAL_ENABLE	BIT(10)
174 
175 #define EMC_XM2QUSEPADCTRL_IVREF_ENABLE		BIT(4)
176 
177 #define EMC_XM2DQSPADCTRL2_VREF_ENABLE		BIT(5)
178 #define EMC_XM2DQSPADCTRL3_VREF_ENABLE		BIT(5)
179 
180 #define EMC_AUTO_CAL_STATUS_ACTIVE		BIT(31)
181 
182 #define	EMC_FBIO_CFG5_DRAM_TYPE_MASK		0x3
183 
184 #define EMC_MRS_WAIT_CNT_SHORT_WAIT_MASK	0x3ff
185 #define EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT	16
186 #define EMC_MRS_WAIT_CNT_LONG_WAIT_MASK \
187 	(0x3ff << EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT)
188 
189 #define EMC_REFCTRL_DEV_SEL_MASK		0x3
190 #define EMC_REFCTRL_ENABLE			BIT(31)
191 #define EMC_REFCTRL_ENABLE_ALL(num) \
192 	(((num) > 1 ? 0 : 2) | EMC_REFCTRL_ENABLE)
193 #define EMC_REFCTRL_DISABLE_ALL(num)		((num) > 1 ? 0 : 2)
194 
195 #define EMC_CFG_PERIODIC_QRST			BIT(21)
196 #define EMC_CFG_DYN_SREF_ENABLE			BIT(28)
197 
198 #define EMC_CLKCHANGE_REQ_ENABLE		BIT(0)
199 #define EMC_CLKCHANGE_PD_ENABLE			BIT(1)
200 #define EMC_CLKCHANGE_SR_ENABLE			BIT(2)
201 
202 #define EMC_TIMING_UPDATE			BIT(0)
203 
204 #define EMC_REFRESH_OVERFLOW_INT		BIT(3)
205 #define EMC_CLKCHANGE_COMPLETE_INT		BIT(4)
206 
207 enum emc_dram_type {
208 	DRAM_TYPE_DDR3,
209 	DRAM_TYPE_DDR1,
210 	DRAM_TYPE_LPDDR2,
211 	DRAM_TYPE_DDR2,
212 };
213 
214 enum emc_dll_change {
215 	DLL_CHANGE_NONE,
216 	DLL_CHANGE_ON,
217 	DLL_CHANGE_OFF
218 };
219 
220 static const u16 emc_timing_registers[] = {
221 	[0] = EMC_RC,
222 	[1] = EMC_RFC,
223 	[2] = EMC_RAS,
224 	[3] = EMC_RP,
225 	[4] = EMC_R2W,
226 	[5] = EMC_W2R,
227 	[6] = EMC_R2P,
228 	[7] = EMC_W2P,
229 	[8] = EMC_RD_RCD,
230 	[9] = EMC_WR_RCD,
231 	[10] = EMC_RRD,
232 	[11] = EMC_REXT,
233 	[12] = EMC_WEXT,
234 	[13] = EMC_WDV,
235 	[14] = EMC_QUSE,
236 	[15] = EMC_QRST,
237 	[16] = EMC_QSAFE,
238 	[17] = EMC_RDV,
239 	[18] = EMC_REFRESH,
240 	[19] = EMC_BURST_REFRESH_NUM,
241 	[20] = EMC_PRE_REFRESH_REQ_CNT,
242 	[21] = EMC_PDEX2WR,
243 	[22] = EMC_PDEX2RD,
244 	[23] = EMC_PCHG2PDEN,
245 	[24] = EMC_ACT2PDEN,
246 	[25] = EMC_AR2PDEN,
247 	[26] = EMC_RW2PDEN,
248 	[27] = EMC_TXSR,
249 	[28] = EMC_TXSRDLL,
250 	[29] = EMC_TCKE,
251 	[30] = EMC_TFAW,
252 	[31] = EMC_TRPAB,
253 	[32] = EMC_TCLKSTABLE,
254 	[33] = EMC_TCLKSTOP,
255 	[34] = EMC_TREFBW,
256 	[35] = EMC_QUSE_EXTRA,
257 	[36] = EMC_FBIO_CFG6,
258 	[37] = EMC_ODT_WRITE,
259 	[38] = EMC_ODT_READ,
260 	[39] = EMC_FBIO_CFG5,
261 	[40] = EMC_CFG_DIG_DLL,
262 	[41] = EMC_CFG_DIG_DLL_PERIOD,
263 	[42] = EMC_DLL_XFORM_DQS0,
264 	[43] = EMC_DLL_XFORM_DQS1,
265 	[44] = EMC_DLL_XFORM_DQS2,
266 	[45] = EMC_DLL_XFORM_DQS3,
267 	[46] = EMC_DLL_XFORM_DQS4,
268 	[47] = EMC_DLL_XFORM_DQS5,
269 	[48] = EMC_DLL_XFORM_DQS6,
270 	[49] = EMC_DLL_XFORM_DQS7,
271 	[50] = EMC_DLL_XFORM_QUSE0,
272 	[51] = EMC_DLL_XFORM_QUSE1,
273 	[52] = EMC_DLL_XFORM_QUSE2,
274 	[53] = EMC_DLL_XFORM_QUSE3,
275 	[54] = EMC_DLL_XFORM_QUSE4,
276 	[55] = EMC_DLL_XFORM_QUSE5,
277 	[56] = EMC_DLL_XFORM_QUSE6,
278 	[57] = EMC_DLL_XFORM_QUSE7,
279 	[58] = EMC_DLI_TRIM_TXDQS0,
280 	[59] = EMC_DLI_TRIM_TXDQS1,
281 	[60] = EMC_DLI_TRIM_TXDQS2,
282 	[61] = EMC_DLI_TRIM_TXDQS3,
283 	[62] = EMC_DLI_TRIM_TXDQS4,
284 	[63] = EMC_DLI_TRIM_TXDQS5,
285 	[64] = EMC_DLI_TRIM_TXDQS6,
286 	[65] = EMC_DLI_TRIM_TXDQS7,
287 	[66] = EMC_DLL_XFORM_DQ0,
288 	[67] = EMC_DLL_XFORM_DQ1,
289 	[68] = EMC_DLL_XFORM_DQ2,
290 	[69] = EMC_DLL_XFORM_DQ3,
291 	[70] = EMC_XM2CMDPADCTRL,
292 	[71] = EMC_XM2DQSPADCTRL2,
293 	[72] = EMC_XM2DQPADCTRL2,
294 	[73] = EMC_XM2CLKPADCTRL,
295 	[74] = EMC_XM2COMPPADCTRL,
296 	[75] = EMC_XM2VTTGENPADCTRL,
297 	[76] = EMC_XM2VTTGENPADCTRL2,
298 	[77] = EMC_XM2QUSEPADCTRL,
299 	[78] = EMC_XM2DQSPADCTRL3,
300 	[79] = EMC_CTT_TERM_CTRL,
301 	[80] = EMC_ZCAL_INTERVAL,
302 	[81] = EMC_ZCAL_WAIT_CNT,
303 	[82] = EMC_MRS_WAIT_CNT,
304 	[83] = EMC_AUTO_CAL_CONFIG,
305 	[84] = EMC_CTT,
306 	[85] = EMC_CTT_DURATION,
307 	[86] = EMC_DYN_SELF_REF_CONTROL,
308 	[87] = EMC_FBIO_SPARE,
309 	[88] = EMC_CFG_RSV,
310 };
311 
312 struct emc_timing {
313 	unsigned long rate;
314 
315 	u32 data[ARRAY_SIZE(emc_timing_registers)];
316 
317 	u32 emc_auto_cal_interval;
318 	u32 emc_mode_1;
319 	u32 emc_mode_2;
320 	u32 emc_mode_reset;
321 	u32 emc_zcal_cnt_long;
322 	bool emc_cfg_periodic_qrst;
323 	bool emc_cfg_dyn_self_ref;
324 };
325 
326 struct tegra_emc {
327 	struct device *dev;
328 	struct tegra_mc *mc;
329 	struct completion clk_handshake_complete;
330 	struct notifier_block clk_nb;
331 	struct clk *clk;
332 	void __iomem *regs;
333 	unsigned int irq;
334 
335 	struct emc_timing *timings;
336 	unsigned int num_timings;
337 
338 	u32 mc_override;
339 	u32 emc_cfg;
340 
341 	u32 emc_mode_1;
342 	u32 emc_mode_2;
343 	u32 emc_mode_reset;
344 
345 	bool vref_cal_toggle : 1;
346 	bool zcal_long : 1;
347 	bool dll_on : 1;
348 	bool prepared : 1;
349 	bool bad_state : 1;
350 };
351 
352 static irqreturn_t tegra_emc_isr(int irq, void *data)
353 {
354 	struct tegra_emc *emc = data;
355 	u32 intmask = EMC_REFRESH_OVERFLOW_INT | EMC_CLKCHANGE_COMPLETE_INT;
356 	u32 status;
357 
358 	status = readl_relaxed(emc->regs + EMC_INTSTATUS) & intmask;
359 	if (!status)
360 		return IRQ_NONE;
361 
362 	/* notify about EMC-CAR handshake completion */
363 	if (status & EMC_CLKCHANGE_COMPLETE_INT)
364 		complete(&emc->clk_handshake_complete);
365 
366 	/* notify about HW problem */
367 	if (status & EMC_REFRESH_OVERFLOW_INT)
368 		dev_err_ratelimited(emc->dev,
369 				    "refresh request overflow timeout\n");
370 
371 	/* clear interrupts */
372 	writel_relaxed(status, emc->regs + EMC_INTSTATUS);
373 
374 	return IRQ_HANDLED;
375 }
376 
377 static struct emc_timing *emc_find_timing(struct tegra_emc *emc,
378 					  unsigned long rate)
379 {
380 	struct emc_timing *timing = NULL;
381 	unsigned int i;
382 
383 	for (i = 0; i < emc->num_timings; i++) {
384 		if (emc->timings[i].rate >= rate) {
385 			timing = &emc->timings[i];
386 			break;
387 		}
388 	}
389 
390 	if (!timing) {
391 		dev_err(emc->dev, "no timing for rate %lu\n", rate);
392 		return NULL;
393 	}
394 
395 	return timing;
396 }
397 
398 static bool emc_dqs_preset(struct tegra_emc *emc, struct emc_timing *timing,
399 			   bool *schmitt_to_vref)
400 {
401 	bool preset = false;
402 	u32 val;
403 
404 	if (timing->data[71] & EMC_XM2DQSPADCTRL2_VREF_ENABLE) {
405 		val = readl_relaxed(emc->regs + EMC_XM2DQSPADCTRL2);
406 
407 		if (!(val & EMC_XM2DQSPADCTRL2_VREF_ENABLE)) {
408 			val |= EMC_XM2DQSPADCTRL2_VREF_ENABLE;
409 			writel_relaxed(val, emc->regs + EMC_XM2DQSPADCTRL2);
410 
411 			preset = true;
412 		}
413 	}
414 
415 	if (timing->data[78] & EMC_XM2DQSPADCTRL3_VREF_ENABLE) {
416 		val = readl_relaxed(emc->regs + EMC_XM2DQSPADCTRL3);
417 
418 		if (!(val & EMC_XM2DQSPADCTRL3_VREF_ENABLE)) {
419 			val |= EMC_XM2DQSPADCTRL3_VREF_ENABLE;
420 			writel_relaxed(val, emc->regs + EMC_XM2DQSPADCTRL3);
421 
422 			preset = true;
423 		}
424 	}
425 
426 	if (timing->data[77] & EMC_XM2QUSEPADCTRL_IVREF_ENABLE) {
427 		val = readl_relaxed(emc->regs + EMC_XM2QUSEPADCTRL);
428 
429 		if (!(val & EMC_XM2QUSEPADCTRL_IVREF_ENABLE)) {
430 			val |= EMC_XM2QUSEPADCTRL_IVREF_ENABLE;
431 			writel_relaxed(val, emc->regs + EMC_XM2QUSEPADCTRL);
432 
433 			*schmitt_to_vref = true;
434 			preset = true;
435 		}
436 	}
437 
438 	return preset;
439 }
440 
441 static int emc_seq_update_timing(struct tegra_emc *emc)
442 {
443 	u32 val;
444 	int err;
445 
446 	writel_relaxed(EMC_TIMING_UPDATE, emc->regs + EMC_TIMING_CONTROL);
447 
448 	err = readl_relaxed_poll_timeout_atomic(emc->regs + EMC_STATUS, val,
449 				!(val & EMC_STATUS_TIMING_UPDATE_STALLED),
450 				1, 200);
451 	if (err) {
452 		dev_err(emc->dev, "failed to update timing: %d\n", err);
453 		return err;
454 	}
455 
456 	return 0;
457 }
458 
459 static int emc_prepare_mc_clk_cfg(struct tegra_emc *emc, unsigned long rate)
460 {
461 	struct tegra_mc *mc = emc->mc;
462 	unsigned int misc0_index = 16;
463 	unsigned int i;
464 	bool same;
465 
466 	for (i = 0; i < mc->num_timings; i++) {
467 		if (mc->timings[i].rate != rate)
468 			continue;
469 
470 		if (mc->timings[i].emem_data[misc0_index] & BIT(27))
471 			same = true;
472 		else
473 			same = false;
474 
475 		return tegra20_clk_prepare_emc_mc_same_freq(emc->clk, same);
476 	}
477 
478 	return -EINVAL;
479 }
480 
481 static int emc_prepare_timing_change(struct tegra_emc *emc, unsigned long rate)
482 {
483 	struct emc_timing *timing = emc_find_timing(emc, rate);
484 	enum emc_dll_change dll_change;
485 	enum emc_dram_type dram_type;
486 	bool schmitt_to_vref = false;
487 	unsigned int pre_wait = 0;
488 	bool qrst_used = false;
489 	unsigned int dram_num;
490 	unsigned int i;
491 	u32 fbio_cfg5;
492 	u32 emc_dbg;
493 	u32 val;
494 	int err;
495 
496 	if (!timing || emc->bad_state)
497 		return -EINVAL;
498 
499 	dev_dbg(emc->dev, "%s: using timing rate %lu for requested rate %lu\n",
500 		__func__, timing->rate, rate);
501 
502 	emc->bad_state = true;
503 
504 	err = emc_prepare_mc_clk_cfg(emc, rate);
505 	if (err) {
506 		dev_err(emc->dev, "mc clock preparation failed: %d\n", err);
507 		return err;
508 	}
509 
510 	emc->vref_cal_toggle = false;
511 	emc->mc_override = mc_readl(emc->mc, MC_EMEM_ARB_OVERRIDE);
512 	emc->emc_cfg = readl_relaxed(emc->regs + EMC_CFG);
513 	emc_dbg = readl_relaxed(emc->regs + EMC_DBG);
514 
515 	if (emc->dll_on == !!(timing->emc_mode_1 & 0x1))
516 		dll_change = DLL_CHANGE_NONE;
517 	else if (timing->emc_mode_1 & 0x1)
518 		dll_change = DLL_CHANGE_ON;
519 	else
520 		dll_change = DLL_CHANGE_OFF;
521 
522 	emc->dll_on = !!(timing->emc_mode_1 & 0x1);
523 
524 	if (timing->data[80] && !readl_relaxed(emc->regs + EMC_ZCAL_INTERVAL))
525 		emc->zcal_long = true;
526 	else
527 		emc->zcal_long = false;
528 
529 	fbio_cfg5 = readl_relaxed(emc->regs + EMC_FBIO_CFG5);
530 	dram_type = fbio_cfg5 & EMC_FBIO_CFG5_DRAM_TYPE_MASK;
531 
532 	dram_num = tegra_mc_get_emem_device_count(emc->mc);
533 
534 	/* disable dynamic self-refresh */
535 	if (emc->emc_cfg & EMC_CFG_DYN_SREF_ENABLE) {
536 		emc->emc_cfg &= ~EMC_CFG_DYN_SREF_ENABLE;
537 		writel_relaxed(emc->emc_cfg, emc->regs + EMC_CFG);
538 
539 		pre_wait = 5;
540 	}
541 
542 	/* update MC arbiter settings */
543 	val = mc_readl(emc->mc, MC_EMEM_ARB_OUTSTANDING_REQ);
544 	if (!(val & MC_EMEM_ARB_OUTSTANDING_REQ_HOLDOFF_OVERRIDE) ||
545 	    ((val & MC_EMEM_ARB_OUTSTANDING_REQ_MAX_MASK) > 0x50)) {
546 
547 		val = MC_EMEM_ARB_OUTSTANDING_REQ_LIMIT_ENABLE |
548 		      MC_EMEM_ARB_OUTSTANDING_REQ_HOLDOFF_OVERRIDE | 0x50;
549 		mc_writel(emc->mc, val, MC_EMEM_ARB_OUTSTANDING_REQ);
550 		mc_writel(emc->mc, MC_TIMING_UPDATE, MC_TIMING_CONTROL);
551 	}
552 
553 	if (emc->mc_override & MC_EMEM_ARB_OVERRIDE_EACK_MASK)
554 		mc_writel(emc->mc,
555 			  emc->mc_override & ~MC_EMEM_ARB_OVERRIDE_EACK_MASK,
556 			  MC_EMEM_ARB_OVERRIDE);
557 
558 	/* check DQ/DQS VREF delay */
559 	if (emc_dqs_preset(emc, timing, &schmitt_to_vref)) {
560 		if (pre_wait < 3)
561 			pre_wait = 3;
562 	}
563 
564 	if (pre_wait) {
565 		err = emc_seq_update_timing(emc);
566 		if (err)
567 			return err;
568 
569 		udelay(pre_wait);
570 	}
571 
572 	/* disable auto-calibration if VREF mode is switching */
573 	if (timing->emc_auto_cal_interval) {
574 		val = readl_relaxed(emc->regs + EMC_XM2COMPPADCTRL);
575 		val ^= timing->data[74];
576 
577 		if (val & EMC_XM2COMPPADCTRL_VREF_CAL_ENABLE) {
578 			writel_relaxed(0, emc->regs + EMC_AUTO_CAL_INTERVAL);
579 
580 			err = readl_relaxed_poll_timeout_atomic(
581 				emc->regs + EMC_AUTO_CAL_STATUS, val,
582 				!(val & EMC_AUTO_CAL_STATUS_ACTIVE), 1, 300);
583 			if (err) {
584 				dev_err(emc->dev,
585 					"failed to disable auto-cal: %d\n",
586 					err);
587 				return err;
588 			}
589 
590 			emc->vref_cal_toggle = true;
591 		}
592 	}
593 
594 	/* program shadow registers */
595 	for (i = 0; i < ARRAY_SIZE(timing->data); i++) {
596 		/* EMC_XM2CLKPADCTRL should be programmed separately */
597 		if (i != 73)
598 			writel_relaxed(timing->data[i],
599 				       emc->regs + emc_timing_registers[i]);
600 	}
601 
602 	err = tegra_mc_write_emem_configuration(emc->mc, timing->rate);
603 	if (err)
604 		return err;
605 
606 	/* DDR3: predict MRS long wait count */
607 	if (dram_type == DRAM_TYPE_DDR3 && dll_change == DLL_CHANGE_ON) {
608 		u32 cnt = 512;
609 
610 		if (emc->zcal_long)
611 			cnt -= dram_num * 256;
612 
613 		val = timing->data[82] & EMC_MRS_WAIT_CNT_SHORT_WAIT_MASK;
614 		if (cnt < val)
615 			cnt = val;
616 
617 		val = timing->data[82] & ~EMC_MRS_WAIT_CNT_LONG_WAIT_MASK;
618 		val |= (cnt << EMC_MRS_WAIT_CNT_LONG_WAIT_SHIFT) &
619 			EMC_MRS_WAIT_CNT_LONG_WAIT_MASK;
620 
621 		writel_relaxed(val, emc->regs + EMC_MRS_WAIT_CNT);
622 	}
623 
624 	/* disable interrupt since read access is prohibited after stalling */
625 	disable_irq(emc->irq);
626 
627 	/* this read also completes the writes */
628 	val = readl_relaxed(emc->regs + EMC_SEL_DPD_CTRL);
629 
630 	if (!(val & EMC_SEL_DPD_CTRL_QUSE_DPD_ENABLE) && schmitt_to_vref) {
631 		u32 cur_mode, new_mode;
632 
633 		cur_mode = fbio_cfg5 & EMC_CFG5_QUSE_MODE_MASK;
634 		cur_mode >>= EMC_CFG5_QUSE_MODE_SHIFT;
635 
636 		new_mode = timing->data[39] & EMC_CFG5_QUSE_MODE_MASK;
637 		new_mode >>= EMC_CFG5_QUSE_MODE_SHIFT;
638 
639 		if ((cur_mode != EMC_CFG5_QUSE_MODE_PULSE_INTERN &&
640 		     cur_mode != EMC_CFG5_QUSE_MODE_INTERNAL_LPBK) ||
641 		    (new_mode != EMC_CFG5_QUSE_MODE_PULSE_INTERN &&
642 		     new_mode != EMC_CFG5_QUSE_MODE_INTERNAL_LPBK))
643 			qrst_used = true;
644 	}
645 
646 	/* flow control marker 1 */
647 	writel_relaxed(0x1, emc->regs + EMC_STALL_THEN_EXE_BEFORE_CLKCHANGE);
648 
649 	/* enable periodic reset */
650 	if (qrst_used) {
651 		writel_relaxed(emc_dbg | EMC_DBG_WRITE_MUX_ACTIVE,
652 			       emc->regs + EMC_DBG);
653 		writel_relaxed(emc->emc_cfg | EMC_CFG_PERIODIC_QRST,
654 			       emc->regs + EMC_CFG);
655 		writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
656 	}
657 
658 	/* disable auto-refresh to save time after clock change */
659 	writel_relaxed(EMC_REFCTRL_DISABLE_ALL(dram_num),
660 		       emc->regs + EMC_REFCTRL);
661 
662 	/* turn off DLL and enter self-refresh on DDR3 */
663 	if (dram_type == DRAM_TYPE_DDR3) {
664 		if (dll_change == DLL_CHANGE_OFF)
665 			writel_relaxed(timing->emc_mode_1,
666 				       emc->regs + EMC_EMRS);
667 
668 		writel_relaxed(DRAM_BROADCAST(dram_num) |
669 			       EMC_SELF_REF_CMD_ENABLED,
670 			       emc->regs + EMC_SELF_REF);
671 	}
672 
673 	/* flow control marker 2 */
674 	writel_relaxed(0x1, emc->regs + EMC_STALL_THEN_EXE_AFTER_CLKCHANGE);
675 
676 	/* enable write-active MUX, update unshadowed pad control */
677 	writel_relaxed(emc_dbg | EMC_DBG_WRITE_MUX_ACTIVE, emc->regs + EMC_DBG);
678 	writel_relaxed(timing->data[73], emc->regs + EMC_XM2CLKPADCTRL);
679 
680 	/* restore periodic QRST and disable write-active MUX */
681 	val = !!(emc->emc_cfg & EMC_CFG_PERIODIC_QRST);
682 	if (qrst_used || timing->emc_cfg_periodic_qrst != val) {
683 		if (timing->emc_cfg_periodic_qrst)
684 			emc->emc_cfg |= EMC_CFG_PERIODIC_QRST;
685 		else
686 			emc->emc_cfg &= ~EMC_CFG_PERIODIC_QRST;
687 
688 		writel_relaxed(emc->emc_cfg, emc->regs + EMC_CFG);
689 	}
690 	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
691 
692 	/* exit self-refresh on DDR3 */
693 	if (dram_type == DRAM_TYPE_DDR3)
694 		writel_relaxed(DRAM_BROADCAST(dram_num),
695 			       emc->regs + EMC_SELF_REF);
696 
697 	/* set DRAM-mode registers */
698 	if (dram_type == DRAM_TYPE_DDR3) {
699 		if (timing->emc_mode_1 != emc->emc_mode_1)
700 			writel_relaxed(timing->emc_mode_1,
701 				       emc->regs + EMC_EMRS);
702 
703 		if (timing->emc_mode_2 != emc->emc_mode_2)
704 			writel_relaxed(timing->emc_mode_2,
705 				       emc->regs + EMC_EMRS);
706 
707 		if (timing->emc_mode_reset != emc->emc_mode_reset ||
708 		    dll_change == DLL_CHANGE_ON) {
709 			val = timing->emc_mode_reset;
710 			if (dll_change == DLL_CHANGE_ON) {
711 				val |= EMC_MODE_SET_DLL_RESET;
712 				val |= EMC_MODE_SET_LONG_CNT;
713 			} else {
714 				val &= ~EMC_MODE_SET_DLL_RESET;
715 			}
716 			writel_relaxed(val, emc->regs + EMC_MRS);
717 		}
718 	} else {
719 		if (timing->emc_mode_2 != emc->emc_mode_2)
720 			writel_relaxed(timing->emc_mode_2,
721 				       emc->regs + EMC_MRW);
722 
723 		if (timing->emc_mode_1 != emc->emc_mode_1)
724 			writel_relaxed(timing->emc_mode_1,
725 				       emc->regs + EMC_MRW);
726 	}
727 
728 	emc->emc_mode_1 = timing->emc_mode_1;
729 	emc->emc_mode_2 = timing->emc_mode_2;
730 	emc->emc_mode_reset = timing->emc_mode_reset;
731 
732 	/* issue ZCAL command if turning ZCAL on */
733 	if (emc->zcal_long) {
734 		writel_relaxed(EMC_ZQ_CAL_LONG_CMD_DEV0,
735 			       emc->regs + EMC_ZQ_CAL);
736 
737 		if (dram_num > 1)
738 			writel_relaxed(EMC_ZQ_CAL_LONG_CMD_DEV1,
739 				       emc->regs + EMC_ZQ_CAL);
740 	}
741 
742 	/* re-enable auto-refresh */
743 	writel_relaxed(EMC_REFCTRL_ENABLE_ALL(dram_num),
744 		       emc->regs + EMC_REFCTRL);
745 
746 	/* flow control marker 3 */
747 	writel_relaxed(0x1, emc->regs + EMC_UNSTALL_RW_AFTER_CLKCHANGE);
748 
749 	reinit_completion(&emc->clk_handshake_complete);
750 
751 	/* interrupt can be re-enabled now */
752 	enable_irq(emc->irq);
753 
754 	emc->bad_state = false;
755 	emc->prepared = true;
756 
757 	return 0;
758 }
759 
760 static int emc_complete_timing_change(struct tegra_emc *emc,
761 				      unsigned long rate)
762 {
763 	struct emc_timing *timing = emc_find_timing(emc, rate);
764 	unsigned long timeout;
765 	int ret;
766 
767 	timeout = wait_for_completion_timeout(&emc->clk_handshake_complete,
768 					      msecs_to_jiffies(100));
769 	if (timeout == 0) {
770 		dev_err(emc->dev, "emc-car handshake failed\n");
771 		emc->bad_state = true;
772 		return -EIO;
773 	}
774 
775 	/* restore auto-calibration */
776 	if (emc->vref_cal_toggle)
777 		writel_relaxed(timing->emc_auto_cal_interval,
778 			       emc->regs + EMC_AUTO_CAL_INTERVAL);
779 
780 	/* restore dynamic self-refresh */
781 	if (timing->emc_cfg_dyn_self_ref) {
782 		emc->emc_cfg |= EMC_CFG_DYN_SREF_ENABLE;
783 		writel_relaxed(emc->emc_cfg, emc->regs + EMC_CFG);
784 	}
785 
786 	/* set number of clocks to wait after each ZQ command */
787 	if (emc->zcal_long)
788 		writel_relaxed(timing->emc_zcal_cnt_long,
789 			       emc->regs + EMC_ZCAL_WAIT_CNT);
790 
791 	udelay(2);
792 	/* update restored timing */
793 	ret = emc_seq_update_timing(emc);
794 	if (ret)
795 		emc->bad_state = true;
796 
797 	/* restore early ACK */
798 	mc_writel(emc->mc, emc->mc_override, MC_EMEM_ARB_OVERRIDE);
799 
800 	emc->prepared = false;
801 
802 	return ret;
803 }
804 
805 static int emc_unprepare_timing_change(struct tegra_emc *emc,
806 				       unsigned long rate)
807 {
808 	if (emc->prepared && !emc->bad_state) {
809 		/* shouldn't ever happen in practice */
810 		dev_err(emc->dev, "timing configuration can't be reverted\n");
811 		emc->bad_state = true;
812 	}
813 
814 	return 0;
815 }
816 
817 static int emc_clk_change_notify(struct notifier_block *nb,
818 				 unsigned long msg, void *data)
819 {
820 	struct tegra_emc *emc = container_of(nb, struct tegra_emc, clk_nb);
821 	struct clk_notifier_data *cnd = data;
822 	int err;
823 
824 	switch (msg) {
825 	case PRE_RATE_CHANGE:
826 		err = emc_prepare_timing_change(emc, cnd->new_rate);
827 		break;
828 
829 	case ABORT_RATE_CHANGE:
830 		err = emc_unprepare_timing_change(emc, cnd->old_rate);
831 		break;
832 
833 	case POST_RATE_CHANGE:
834 		err = emc_complete_timing_change(emc, cnd->new_rate);
835 		break;
836 
837 	default:
838 		return NOTIFY_DONE;
839 	}
840 
841 	return notifier_from_errno(err);
842 }
843 
844 static int load_one_timing_from_dt(struct tegra_emc *emc,
845 				   struct emc_timing *timing,
846 				   struct device_node *node)
847 {
848 	u32 value;
849 	int err;
850 
851 	err = of_property_read_u32(node, "clock-frequency", &value);
852 	if (err) {
853 		dev_err(emc->dev, "timing %pOF: failed to read rate: %d\n",
854 			node, err);
855 		return err;
856 	}
857 
858 	timing->rate = value;
859 
860 	err = of_property_read_u32_array(node, "nvidia,emc-configuration",
861 					 timing->data,
862 					 ARRAY_SIZE(emc_timing_registers));
863 	if (err) {
864 		dev_err(emc->dev,
865 			"timing %pOF: failed to read emc timing data: %d\n",
866 			node, err);
867 		return err;
868 	}
869 
870 #define EMC_READ_BOOL(prop, dtprop) \
871 	timing->prop = of_property_read_bool(node, dtprop);
872 
873 #define EMC_READ_U32(prop, dtprop) \
874 	err = of_property_read_u32(node, dtprop, &timing->prop); \
875 	if (err) { \
876 		dev_err(emc->dev, \
877 			"timing %pOFn: failed to read " #prop ": %d\n", \
878 			node, err); \
879 		return err; \
880 	}
881 
882 	EMC_READ_U32(emc_auto_cal_interval, "nvidia,emc-auto-cal-interval")
883 	EMC_READ_U32(emc_mode_1, "nvidia,emc-mode-1")
884 	EMC_READ_U32(emc_mode_2, "nvidia,emc-mode-2")
885 	EMC_READ_U32(emc_mode_reset, "nvidia,emc-mode-reset")
886 	EMC_READ_U32(emc_zcal_cnt_long, "nvidia,emc-zcal-cnt-long")
887 	EMC_READ_BOOL(emc_cfg_dyn_self_ref, "nvidia,emc-cfg-dyn-self-ref")
888 	EMC_READ_BOOL(emc_cfg_periodic_qrst, "nvidia,emc-cfg-periodic-qrst")
889 
890 #undef EMC_READ_U32
891 #undef EMC_READ_BOOL
892 
893 	dev_dbg(emc->dev, "%s: %pOF: rate %lu\n", __func__, node, timing->rate);
894 
895 	return 0;
896 }
897 
898 static int cmp_timings(const void *_a, const void *_b)
899 {
900 	const struct emc_timing *a = _a;
901 	const struct emc_timing *b = _b;
902 
903 	if (a->rate < b->rate)
904 		return -1;
905 
906 	if (a->rate > b->rate)
907 		return 1;
908 
909 	return 0;
910 }
911 
912 static int emc_check_mc_timings(struct tegra_emc *emc)
913 {
914 	struct tegra_mc *mc = emc->mc;
915 	unsigned int i;
916 
917 	if (emc->num_timings != mc->num_timings) {
918 		dev_err(emc->dev, "emc/mc timings number mismatch: %u %u\n",
919 			emc->num_timings, mc->num_timings);
920 		return -EINVAL;
921 	}
922 
923 	for (i = 0; i < mc->num_timings; i++) {
924 		if (emc->timings[i].rate != mc->timings[i].rate) {
925 			dev_err(emc->dev,
926 				"emc/mc timing rate mismatch: %lu %lu\n",
927 				emc->timings[i].rate, mc->timings[i].rate);
928 			return -EINVAL;
929 		}
930 	}
931 
932 	return 0;
933 }
934 
935 static int emc_load_timings_from_dt(struct tegra_emc *emc,
936 				    struct device_node *node)
937 {
938 	struct device_node *child;
939 	struct emc_timing *timing;
940 	int child_count;
941 	int err;
942 
943 	child_count = of_get_child_count(node);
944 	if (!child_count) {
945 		dev_err(emc->dev, "no memory timings in: %pOF\n", node);
946 		return -EINVAL;
947 	}
948 
949 	emc->timings = devm_kcalloc(emc->dev, child_count, sizeof(*timing),
950 				    GFP_KERNEL);
951 	if (!emc->timings)
952 		return -ENOMEM;
953 
954 	emc->num_timings = child_count;
955 	timing = emc->timings;
956 
957 	for_each_child_of_node(node, child) {
958 		err = load_one_timing_from_dt(emc, timing++, child);
959 		if (err) {
960 			of_node_put(child);
961 			return err;
962 		}
963 	}
964 
965 	sort(emc->timings, emc->num_timings, sizeof(*timing), cmp_timings,
966 	     NULL);
967 
968 	err = emc_check_mc_timings(emc);
969 	if (err)
970 		return err;
971 
972 	dev_info(emc->dev,
973 		 "got %u timings for RAM code %u (min %luMHz max %luMHz)\n",
974 		 emc->num_timings,
975 		 tegra_read_ram_code(),
976 		 emc->timings[0].rate / 1000000,
977 		 emc->timings[emc->num_timings - 1].rate / 1000000);
978 
979 	return 0;
980 }
981 
982 static struct device_node *emc_find_node_by_ram_code(struct device *dev)
983 {
984 	struct device_node *np;
985 	u32 value, ram_code;
986 	int err;
987 
988 	ram_code = tegra_read_ram_code();
989 
990 	for_each_child_of_node(dev->of_node, np) {
991 		err = of_property_read_u32(np, "nvidia,ram-code", &value);
992 		if (err || value != ram_code)
993 			continue;
994 
995 		return np;
996 	}
997 
998 	dev_err(dev, "no memory timings for RAM code %u found in device-tree\n",
999 		ram_code);
1000 
1001 	return NULL;
1002 }
1003 
1004 static int emc_setup_hw(struct tegra_emc *emc)
1005 {
1006 	u32 intmask = EMC_REFRESH_OVERFLOW_INT | EMC_CLKCHANGE_COMPLETE_INT;
1007 	u32 fbio_cfg5, emc_cfg, emc_dbg;
1008 	enum emc_dram_type dram_type;
1009 
1010 	fbio_cfg5 = readl_relaxed(emc->regs + EMC_FBIO_CFG5);
1011 	dram_type = fbio_cfg5 & EMC_FBIO_CFG5_DRAM_TYPE_MASK;
1012 
1013 	emc_cfg = readl_relaxed(emc->regs + EMC_CFG_2);
1014 
1015 	/* enable EMC and CAR to handshake on PLL divider/source changes */
1016 	emc_cfg |= EMC_CLKCHANGE_REQ_ENABLE;
1017 
1018 	/* configure clock change mode accordingly to DRAM type */
1019 	switch (dram_type) {
1020 	case DRAM_TYPE_LPDDR2:
1021 		emc_cfg |= EMC_CLKCHANGE_PD_ENABLE;
1022 		emc_cfg &= ~EMC_CLKCHANGE_SR_ENABLE;
1023 		break;
1024 
1025 	default:
1026 		emc_cfg &= ~EMC_CLKCHANGE_SR_ENABLE;
1027 		emc_cfg &= ~EMC_CLKCHANGE_PD_ENABLE;
1028 		break;
1029 	}
1030 
1031 	writel_relaxed(emc_cfg, emc->regs + EMC_CFG_2);
1032 
1033 	/* initialize interrupt */
1034 	writel_relaxed(intmask, emc->regs + EMC_INTMASK);
1035 	writel_relaxed(0xffffffff, emc->regs + EMC_INTSTATUS);
1036 
1037 	/* ensure that unwanted debug features are disabled */
1038 	emc_dbg = readl_relaxed(emc->regs + EMC_DBG);
1039 	emc_dbg |= EMC_DBG_CFG_PRIORITY;
1040 	emc_dbg &= ~EMC_DBG_READ_MUX_ASSEMBLY;
1041 	emc_dbg &= ~EMC_DBG_WRITE_MUX_ACTIVE;
1042 	emc_dbg &= ~EMC_DBG_FORCE_UPDATE;
1043 	writel_relaxed(emc_dbg, emc->regs + EMC_DBG);
1044 
1045 	return 0;
1046 }
1047 
1048 static long emc_round_rate(unsigned long rate,
1049 			   unsigned long min_rate,
1050 			   unsigned long max_rate,
1051 			   void *arg)
1052 {
1053 	struct emc_timing *timing = NULL;
1054 	struct tegra_emc *emc = arg;
1055 	unsigned int i;
1056 
1057 	min_rate = min(min_rate, emc->timings[emc->num_timings - 1].rate);
1058 
1059 	for (i = 0; i < emc->num_timings; i++) {
1060 		if (emc->timings[i].rate < rate && i != emc->num_timings - 1)
1061 			continue;
1062 
1063 		if (emc->timings[i].rate > max_rate) {
1064 			i = max(i, 1u) - 1;
1065 
1066 			if (emc->timings[i].rate < min_rate)
1067 				break;
1068 		}
1069 
1070 		if (emc->timings[i].rate < min_rate)
1071 			continue;
1072 
1073 		timing = &emc->timings[i];
1074 		break;
1075 	}
1076 
1077 	if (!timing) {
1078 		dev_err(emc->dev, "no timing for rate %lu min %lu max %lu\n",
1079 			rate, min_rate, max_rate);
1080 		return -EINVAL;
1081 	}
1082 
1083 	return timing->rate;
1084 }
1085 
1086 static int tegra_emc_probe(struct platform_device *pdev)
1087 {
1088 	struct platform_device *mc;
1089 	struct device_node *np;
1090 	struct tegra_emc *emc;
1091 	int err;
1092 
1093 	if (of_get_child_count(pdev->dev.of_node) == 0) {
1094 		dev_info(&pdev->dev,
1095 			 "device-tree node doesn't have memory timings\n");
1096 		return -ENODEV;
1097 	}
1098 
1099 	np = of_parse_phandle(pdev->dev.of_node, "nvidia,memory-controller", 0);
1100 	if (!np) {
1101 		dev_err(&pdev->dev, "could not get memory controller node\n");
1102 		return -ENOENT;
1103 	}
1104 
1105 	mc = of_find_device_by_node(np);
1106 	of_node_put(np);
1107 	if (!mc)
1108 		return -ENOENT;
1109 
1110 	np = emc_find_node_by_ram_code(&pdev->dev);
1111 	if (!np)
1112 		return -EINVAL;
1113 
1114 	emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
1115 	if (!emc) {
1116 		of_node_put(np);
1117 		return -ENOMEM;
1118 	}
1119 
1120 	emc->mc = platform_get_drvdata(mc);
1121 	if (!emc->mc)
1122 		return -EPROBE_DEFER;
1123 
1124 	init_completion(&emc->clk_handshake_complete);
1125 	emc->clk_nb.notifier_call = emc_clk_change_notify;
1126 	emc->dev = &pdev->dev;
1127 
1128 	err = emc_load_timings_from_dt(emc, np);
1129 	of_node_put(np);
1130 	if (err)
1131 		return err;
1132 
1133 	emc->regs = devm_platform_ioremap_resource(pdev, 0);
1134 	if (IS_ERR(emc->regs))
1135 		return PTR_ERR(emc->regs);
1136 
1137 	err = emc_setup_hw(emc);
1138 	if (err)
1139 		return err;
1140 
1141 	err = platform_get_irq(pdev, 0);
1142 	if (err < 0) {
1143 		dev_err(&pdev->dev, "interrupt not specified: %d\n", err);
1144 		return err;
1145 	}
1146 	emc->irq = err;
1147 
1148 	err = devm_request_irq(&pdev->dev, emc->irq, tegra_emc_isr, 0,
1149 			       dev_name(&pdev->dev), emc);
1150 	if (err) {
1151 		dev_err(&pdev->dev, "failed to request irq: %d\n", err);
1152 		return err;
1153 	}
1154 
1155 	tegra20_clk_set_emc_round_callback(emc_round_rate, emc);
1156 
1157 	emc->clk = devm_clk_get(&pdev->dev, "emc");
1158 	if (IS_ERR(emc->clk)) {
1159 		err = PTR_ERR(emc->clk);
1160 		dev_err(&pdev->dev, "failed to get emc clock: %d\n", err);
1161 		goto unset_cb;
1162 	}
1163 
1164 	err = clk_notifier_register(emc->clk, &emc->clk_nb);
1165 	if (err) {
1166 		dev_err(&pdev->dev, "failed to register clk notifier: %d\n",
1167 			err);
1168 		goto unset_cb;
1169 	}
1170 
1171 	platform_set_drvdata(pdev, emc);
1172 
1173 	return 0;
1174 
1175 unset_cb:
1176 	tegra20_clk_set_emc_round_callback(NULL, NULL);
1177 
1178 	return err;
1179 }
1180 
1181 static int tegra_emc_suspend(struct device *dev)
1182 {
1183 	struct tegra_emc *emc = dev_get_drvdata(dev);
1184 
1185 	/*
1186 	 * Suspending in a bad state will hang machine. The "prepared" var
1187 	 * shall be always false here unless it's a kernel bug that caused
1188 	 * suspending in a wrong order.
1189 	 */
1190 	if (WARN_ON(emc->prepared) || emc->bad_state)
1191 		return -EINVAL;
1192 
1193 	emc->bad_state = true;
1194 
1195 	return 0;
1196 }
1197 
1198 static int tegra_emc_resume(struct device *dev)
1199 {
1200 	struct tegra_emc *emc = dev_get_drvdata(dev);
1201 
1202 	emc_setup_hw(emc);
1203 	emc->bad_state = false;
1204 
1205 	return 0;
1206 }
1207 
1208 static const struct dev_pm_ops tegra_emc_pm_ops = {
1209 	.suspend = tegra_emc_suspend,
1210 	.resume = tegra_emc_resume,
1211 };
1212 
1213 static const struct of_device_id tegra_emc_of_match[] = {
1214 	{ .compatible = "nvidia,tegra30-emc", },
1215 	{},
1216 };
1217 
1218 static struct platform_driver tegra_emc_driver = {
1219 	.probe = tegra_emc_probe,
1220 	.driver = {
1221 		.name = "tegra30-emc",
1222 		.of_match_table = tegra_emc_of_match,
1223 		.pm = &tegra_emc_pm_ops,
1224 		.suppress_bind_attrs = true,
1225 	},
1226 };
1227 
1228 static int __init tegra_emc_init(void)
1229 {
1230 	return platform_driver_register(&tegra_emc_driver);
1231 }
1232 subsys_initcall(tegra_emc_init);
1233