ti-aemif.c 12 KB
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436
/*
 * 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>
#include <linux/platform_data/ti-aemif.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", },
	{},
};
MODULE_DEVICE_TABLE(of, aemif_of_match);

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;
	struct aemif_platform_data *pdata;
	struct of_dev_auxdata *dev_lookup;

	if (np == NULL)
		return 0;

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

	pdata = dev_get_platdata(&pdev->dev);
	dev_lookup = pdata ? pdata->dev_lookup : NULL;

	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);
	}

	ret = clk_prepare_enable(aemif->clk);
	if (ret)
		return ret;

	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, dev_lookup, 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,
		.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);