summaryrefslogtreecommitdiffstats
path: root/drivers/memory/ti-aemif.c
blob: d3df7602f40666fffcd6bd6e5aad67b37985d837 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
/*
 * TI AEMIF driver
 *
 * Copyright (C) 2010 - 2013 Texas Instruments Incorporated. http://www.ti.com/
 *
 * Authors:
 * Murali Karicheri <m-karicheri2@ti.com>
 * Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>

#define TA_SHIFT	2
#define RHOLD_SHIFT	4
#define RSTROBE_SHIFT	7
#define RSETUP_SHIFT	13
#define WHOLD_SHIFT	17
#define WSTROBE_SHIFT	20
#define WSETUP_SHIFT	26
#define EW_SHIFT	30
#define SS_SHIFT	31

#define TA(x)		((x) << TA_SHIFT)
#define RHOLD(x)	((x) << RHOLD_SHIFT)
#define RSTROBE(x)	((x) << RSTROBE_SHIFT)
#define RSETUP(x)	((x) << RSETUP_SHIFT)
#define WHOLD(x)	((x) << WHOLD_SHIFT)
#define WSTROBE(x)	((x) << WSTROBE_SHIFT)
#define WSETUP(x)	((x) << WSETUP_SHIFT)
#define EW(x)		((x) << EW_SHIFT)
#define SS(x)		((x) << SS_SHIFT)

#define ASIZE_MAX	0x1
#define TA_MAX		0x3
#define RHOLD_MAX	0x7
#define RSTROBE_MAX	0x3f
#define RSETUP_MAX	0xf
#define WHOLD_MAX	0x7
#define WSTROBE_MAX	0x3f
#define WSETUP_MAX	0xf
#define EW_MAX		0x1
#define SS_MAX		0x1
#define NUM_CS		4

#define TA_VAL(x)	(((x) & TA(TA_MAX)) >> TA_SHIFT)
#define RHOLD_VAL(x)	(((x) & RHOLD(RHOLD_MAX)) >> RHOLD_SHIFT)
#define RSTROBE_VAL(x)	(((x) & RSTROBE(RSTROBE_MAX)) >> RSTROBE_SHIFT)
#define RSETUP_VAL(x)	(((x) & RSETUP(RSETUP_MAX)) >> RSETUP_SHIFT)
#define WHOLD_VAL(x)	(((x) & WHOLD(WHOLD_MAX)) >> WHOLD_SHIFT)
#define WSTROBE_VAL(x)	(((x) & WSTROBE(WSTROBE_MAX)) >> WSTROBE_SHIFT)
#define WSETUP_VAL(x)	(((x) & WSETUP(WSETUP_MAX)) >> WSETUP_SHIFT)
#define EW_VAL(x)	(((x) & EW(EW_MAX)) >> EW_SHIFT)
#define SS_VAL(x)	(((x) & SS(SS_MAX)) >> SS_SHIFT)

#define NRCSR_OFFSET	0x00
#define AWCCR_OFFSET	0x04
#define A1CR_OFFSET	0x10

#define ACR_ASIZE_MASK	0x3
#define ACR_EW_MASK	BIT(30)
#define ACR_SS_MASK	BIT(31)
#define ASIZE_16BIT	1

#define CONFIG_MASK	(TA(TA_MAX) | \
				RHOLD(RHOLD_MAX) | \
				RSTROBE(RSTROBE_MAX) |	\
				RSETUP(RSETUP_MAX) | \
				WHOLD(WHOLD_MAX) | \
				WSTROBE(WSTROBE_MAX) | \
				WSETUP(WSETUP_MAX) | \
				EW(EW_MAX) | SS(SS_MAX) | \
				ASIZE_MAX)

/**
 * struct aemif_cs_data: structure to hold cs parameters
 * @cs: chip-select number
 * @wstrobe: write strobe width, ns
 * @rstrobe: read strobe width, ns
 * @wsetup: write setup width, ns
 * @whold: write hold width, ns
 * @rsetup: read setup width, ns
 * @rhold: read hold width, ns
 * @ta: minimum turn around time, ns
 * @enable_ss: enable/disable select strobe mode
 * @enable_ew: enable/disable extended wait mode
 * @asize: width of the asynchronous device's data bus
 */
struct aemif_cs_data {
	u8	cs;
	u16	wstrobe;
	u16	rstrobe;
	u8	wsetup;
	u8	whold;
	u8	rsetup;
	u8	rhold;
	u8	ta;
	u8	enable_ss;
	u8	enable_ew;
	u8	asize;
};

/**
 * struct aemif_device: structure to hold device data
 * @base: base address of AEMIF registers
 * @clk: source clock
 * @clk_rate: clock's rate in kHz
 * @num_cs: number of assigned chip-selects
 * @cs_offset: start number of cs nodes
 * @cs_data: array of chip-select settings
 */
struct aemif_device {
	void __iomem *base;
	struct clk *clk;
	unsigned long clk_rate;
	u8 num_cs;
	int cs_offset;
	struct aemif_cs_data cs_data[NUM_CS];
};

/**
 * aemif_calc_rate - calculate timing data.
 * @pdev: platform device to calculate for
 * @wanted: The cycle time needed in nanoseconds.
 * @clk: The input clock rate in kHz.
 * @max: The maximum divider value that can be programmed.
 *
 * On success, returns the calculated timing value minus 1 for easy
 * programming into AEMIF timing registers, else negative errno.
 */
static int aemif_calc_rate(struct platform_device *pdev, int wanted,
			   unsigned long clk, int max)
{
	int result;

	result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1;

	dev_dbg(&pdev->dev, "%s: result %d from %ld, %d\n", __func__, result,
		clk, wanted);

	/* It is generally OK to have a more relaxed timing than requested... */
	if (result < 0)
		result = 0;

	/* ... But configuring tighter timings is not an option. */
	else if (result > max)
		result = -EINVAL;

	return result;
}

/**
 * aemif_config_abus - configure async bus parameters
 * @pdev: platform device to configure for
 * @csnum: aemif chip select number
 *
 * This function programs the given timing values (in real clock) into the
 * AEMIF registers taking the AEMIF clock into account.
 *
 * This function does not use any locking while programming the AEMIF
 * because it is expected that there is only one user of a given
 * chip-select.
 *
 * Returns 0 on success, else negative errno.
 */
static int aemif_config_abus(struct platform_device *pdev, int csnum)
{
	struct aemif_device *aemif = platform_get_drvdata(pdev);
	struct aemif_cs_data *data = &aemif->cs_data[csnum];
	int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup;
	unsigned long clk_rate = aemif->clk_rate;
	unsigned offset;
	u32 set, val;

	offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;

	ta	= aemif_calc_rate(pdev, data->ta, clk_rate, TA_MAX);
	rhold	= aemif_calc_rate(pdev, data->rhold, clk_rate, RHOLD_MAX);
	rstrobe	= aemif_calc_rate(pdev, data->rstrobe, clk_rate, RSTROBE_MAX);
	rsetup	= aemif_calc_rate(pdev, data->rsetup, clk_rate, RSETUP_MAX);
	whold	= aemif_calc_rate(pdev, data->whold, clk_rate, WHOLD_MAX);
	wstrobe	= aemif_calc_rate(pdev, data->wstrobe, clk_rate, WSTROBE_MAX);
	wsetup	= aemif_calc_rate(pdev, data->wsetup, clk_rate, WSETUP_MAX);

	if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 ||
	    whold < 0 || wstrobe < 0 || wsetup < 0) {
		dev_err(&pdev->dev, "%s: cannot get suitable timings\n",
			__func__);
		return -EINVAL;
	}

	set = TA(ta) | RHOLD(rhold) | RSTROBE(rstrobe) | RSETUP(rsetup) |
		WHOLD(whold) | WSTROBE(wstrobe) | WSETUP(wsetup);

	set |= (data->asize & ACR_ASIZE_MASK);
	if (data->enable_ew)
		set |= ACR_EW_MASK;
	if (data->enable_ss)
		set |= ACR_SS_MASK;

	val = readl(aemif->base + offset);
	val &= ~CONFIG_MASK;
	val |= set;
	writel(val, aemif->base + offset);

	return 0;
}

static inline int aemif_cycles_to_nsec(int val, unsigned long clk_rate)
{
	return ((val + 1) * NSEC_PER_MSEC) / clk_rate;
}

/**
 * aemif_get_hw_params - function to read hw register values
 * @pdev: platform device to read for
 * @csnum: aemif chip select number
 *
 * This function reads the defaults from the registers and update
 * the timing values. Required for get/set commands and also for
 * the case when driver needs to use defaults in hardware.
 */
static void aemif_get_hw_params(struct platform_device *pdev, int csnum)
{
	struct aemif_device *aemif = platform_get_drvdata(pdev);
	struct aemif_cs_data *data = &aemif->cs_data[csnum];
	unsigned long clk_rate = aemif->clk_rate;
	u32 val, offset;

	offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4;
	val = readl(aemif->base + offset);

	data->ta = aemif_cycles_to_nsec(TA_VAL(val), clk_rate);
	data->rhold = aemif_cycles_to_nsec(RHOLD_VAL(val), clk_rate);
	data->rstrobe = aemif_cycles_to_nsec(RSTROBE_VAL(val), clk_rate);
	data->rsetup = aemif_cycles_to_nsec(RSETUP_VAL(val), clk_rate);
	data->whold = aemif_cycles_to_nsec(WHOLD_VAL(val), clk_rate);
	data->wstrobe = aemif_cycles_to_nsec(WSTROBE_VAL(val), clk_rate);
	data->wsetup = aemif_cycles_to_nsec(WSETUP_VAL(val), clk_rate);
	data->enable_ew = EW_VAL(val);
	data->enable_ss = SS_VAL(val);
	data->asize = val & ASIZE_MAX;
}

/**
 * of_aemif_parse_abus_config - parse CS configuration from DT
 * @pdev: platform device to parse for
 * @np: device node ptr
 *
 * This function update the emif async bus configuration based on the values
 * configured in a cs device binding node.
 */
static int of_aemif_parse_abus_config(struct platform_device *pdev,
				      struct device_node *np)
{
	struct aemif_device *aemif = platform_get_drvdata(pdev);
	struct aemif_cs_data *data;
	u32 cs;
	u32 val;

	if (of_property_read_u32(np, "ti,cs-chipselect", &cs)) {
		dev_dbg(&pdev->dev, "cs property is required");
		return -EINVAL;
	}

	if (cs - aemif->cs_offset >= NUM_CS || cs < aemif->cs_offset) {
		dev_dbg(&pdev->dev, "cs number is incorrect %d", cs);
		return -EINVAL;
	}

	if (aemif->num_cs >= NUM_CS) {
		dev_dbg(&pdev->dev, "cs count is more than %d", NUM_CS);
		return -EINVAL;
	}

	data = &aemif->cs_data[aemif->num_cs];
	data->cs = cs;

	/* read the current value in the hw register */
	aemif_get_hw_params(pdev, aemif->num_cs++);

	/* override the values from device node */
	if (!of_property_read_u32(np, "ti,cs-min-turnaround-ns", &val))
		data->ta = val;

	if (!of_property_read_u32(np, "ti,cs-read-hold-ns", &val))
		data->rhold = val;

	if (!of_property_read_u32(np, "ti,cs-read-strobe-ns", &val))
		data->rstrobe = val;

	if (!of_property_read_u32(np, "ti,cs-read-setup-ns", &val))
		data->rsetup = val;

	if (!of_property_read_u32(np, "ti,cs-write-hold-ns", &val))
		data->whold = val;

	if (!of_property_read_u32(np, "ti,cs-write-strobe-ns", &val))
		data->wstrobe = val;

	if (!of_property_read_u32(np, "ti,cs-write-setup-ns", &val))
		data->wsetup = val;

	if (!of_property_read_u32(np, "ti,cs-bus-width", &val))
		if (val == 16)
			data->asize = 1;
	data->enable_ew = of_property_read_bool(np, "ti,cs-extended-wait-mode");
	data->enable_ss = of_property_read_bool(np, "ti,cs-select-strobe-mode");
	return 0;
}

static const struct of_device_id aemif_of_match[] = {
	{ .compatible = "ti,davinci-aemif", },
	{ .compatible = "ti,da850-aemif", },
	{},
};

static int aemif_probe(struct platform_device *pdev)
{
	int i;
	int ret = -ENODEV;
	struct resource *res;
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct device_node *child_np;
	struct aemif_device *aemif;

	if (np == NULL)
		return 0;

	aemif = devm_kzalloc(dev, sizeof(*aemif), GFP_KERNEL);
	if (!aemif)
		return -ENOMEM;

	platform_set_drvdata(pdev, aemif);

	aemif->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(aemif->clk)) {
		dev_err(dev, "cannot get clock 'aemif'\n");
		return PTR_ERR(aemif->clk);
	}

	clk_prepare_enable(aemif->clk);
	aemif->clk_rate = clk_get_rate(aemif->clk) / MSEC_PER_SEC;

	if (of_device_is_compatible(np, "ti,da850-aemif"))
		aemif->cs_offset = 2;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	aemif->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(aemif->base)) {
		ret = PTR_ERR(aemif->base);
		goto error;
	}

	/*
	 * For every controller device node, there is a cs device node that
	 * describe the bus configuration parameters. This functions iterate
	 * over these nodes and update the cs data array.
	 */
	for_each_available_child_of_node(np, child_np) {
		ret = of_aemif_parse_abus_config(pdev, child_np);
		if (ret < 0)
			goto error;
	}

	for (i = 0; i < aemif->num_cs; i++) {
		ret = aemif_config_abus(pdev, i);
		if (ret < 0) {
			dev_err(dev, "Error configuring chip select %d\n",
				aemif->cs_data[i].cs);
			goto error;
		}
	}

	/*
	 * Create a child devices explicitly from here to
	 * guarantee that the child will be probed after the AEMIF timing
	 * parameters are set.
	 */
	for_each_available_child_of_node(np, child_np) {
		ret = of_platform_populate(child_np, NULL, NULL, dev);
		if (ret < 0)
			goto error;
	}

	return 0;
error:
	clk_disable_unprepare(aemif->clk);
	return ret;
}

static int aemif_remove(struct platform_device *pdev)
{
	struct aemif_device *aemif = platform_get_drvdata(pdev);

	clk_disable_unprepare(aemif->clk);
	return 0;
}

static struct platform_driver aemif_driver = {
	.probe = aemif_probe,
	.remove = aemif_remove,
	.driver = {
		.name = KBUILD_MODNAME,
		.owner = THIS_MODULE,
		.of_match_table = of_match_ptr(aemif_of_match),
	},
};

module_platform_driver(aemif_driver);

MODULE_AUTHOR("Murali Karicheri <m-karicheri2@ti.com>");
MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>");
MODULE_DESCRIPTION("Texas Instruments AEMIF driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" KBUILD_MODNAME);
OpenPOWER on IntegriCloud