[linux-2.6-block.git] / arch / arm / mach-davinci / aemif.c

/*
 * AEMIF support for DaVinci SoCs
 *
 * Copyright (C) 2010 Texas Instruments Incorporated. http://www.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/kernel.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/time.h>

#include <mach/aemif.h>

/* Timing value configuration */

#define TA(x)		((x) << 2)
#define RHOLD(x)	((x) << 4)
#define RSTROBE(x)	((x) << 7)
#define RSETUP(x)	((x) << 13)
#define WHOLD(x)	((x) << 17)
#define WSTROBE(x)	((x) << 20)
#define WSETUP(x)	((x) << 26)

#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 TIMING_MASK	(TA(TA_MAX) | \
				RHOLD(RHOLD_MAX) | \
				RSTROBE(RSTROBE_MAX) |	\
				RSETUP(RSETUP_MAX) | \
				WHOLD(WHOLD_MAX) | \
				WSTROBE(WSTROBE_MAX) | \
				WSETUP(WSETUP_MAX))

/*
 * aemif_calc_rate - calculate timing data.
 * @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(int wanted, unsigned long clk, int max)
{
	int result;

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

	pr_debug("%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;
}

/**
 * davinci_aemif_setup_timing - setup timing values for a given AEMIF interface
 * @t: timing values to be progammed
 * @base: The virtual base address of the AEMIF interface
 * @cs: chip-select to program the timing values for
 *
 * 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.
 */
int davinci_aemif_setup_timing(struct davinci_aemif_timing *t,
					void __iomem *base, unsigned cs)
{
	unsigned set, val;
	int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup;
	unsigned offset = A1CR_OFFSET + cs * 4;
	struct clk *aemif_clk;
	unsigned long clkrate;

	if (!t)
		return 0;	/* Nothing to do */

	aemif_clk = clk_get(NULL, "aemif");
	if (IS_ERR(aemif_clk))
		return PTR_ERR(aemif_clk);

	clkrate = clk_get_rate(aemif_clk);

	clkrate /= 1000;	/* turn clock into kHz for ease of use */

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

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

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

	val = __raw_readl(base + offset);
	val &= ~TIMING_MASK;
	val |= set;
	__raw_writel(val, base + offset);

	return 0;
}
EXPORT_SYMBOL(davinci_aemif_setup_timing);
Commit	Line	Data
8060ef4d SN	1	/*
	2	* AEMIF support for DaVinci SoCs
	3	*
	4	* Copyright (C) 2010 Texas Instruments Incorporated. http://www.ti.com/
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*/
	10
	11	#include <linux/kernel.h>
	12	#include <linux/io.h>
	13	#include <linux/err.h>
	14	#include <linux/clk.h>
	15	#include <linux/module.h>
	16	#include <linux/time.h>
	17
	18	#include <mach/aemif.h>
	19
	20	/* Timing value configuration */
	21
	22	#define TA(x) ((x) << 2)
	23	#define RHOLD(x) ((x) << 4)
	24	#define RSTROBE(x) ((x) << 7)
	25	#define RSETUP(x) ((x) << 13)
	26	#define WHOLD(x) ((x) << 17)
	27	#define WSTROBE(x) ((x) << 20)
	28	#define WSETUP(x) ((x) << 26)
	29
	30	#define TA_MAX 0x3
	31	#define RHOLD_MAX 0x7
	32	#define RSTROBE_MAX 0x3f
	33	#define RSETUP_MAX 0xf
	34	#define WHOLD_MAX 0x7
	35	#define WSTROBE_MAX 0x3f
	36	#define WSETUP_MAX 0xf
	37
	38	#define TIMING_MASK (TA(TA_MAX) \| \
	39	RHOLD(RHOLD_MAX) \| \
	40	RSTROBE(RSTROBE_MAX) \| \
	41	RSETUP(RSETUP_MAX) \| \
	42	WHOLD(WHOLD_MAX) \| \
	43	WSTROBE(WSTROBE_MAX) \| \
	44	WSETUP(WSETUP_MAX))
	45
	46	/*
	47	* aemif_calc_rate - calculate timing data.
	48	* @wanted: The cycle time needed in nanoseconds.
	49	* @clk: The input clock rate in kHz.
	50	* @max: The maximum divider value that can be programmed.
	51	*
	52	* On success, returns the calculated timing value minus 1 for easy
	53	* programming into AEMIF timing registers, else negative errno.
	54	*/
	55	static int aemif_calc_rate(int wanted, unsigned long clk, int max)
	56	{
	57	int result;
	58
	59	result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1;
	60
	61	pr_debug("%s: result %d from %ld, %d\n", __func__, result, clk, wanted);
	62
	63	/* It is generally OK to have a more relaxed timing than requested... */
	64	if (result < 0)
65	result = 0;
66
67	/* ... But configuring tighter timings is not an option. */
68	else if (result > max)
69	result = -EINVAL;
70
71	return result;
72	}
73
74	/**
75	* davinci_aemif_setup_timing - setup timing values for a given AEMIF interface
76	* @t: timing values to be progammed
77	* @base: The virtual base address of the AEMIF interface
78	* @cs: chip-select to program the timing values for
79	*
80	* This function programs the given timing values (in real clock) into the
81	* AEMIF registers taking the AEMIF clock into account.
82	*
83	* This function does not use any locking while programming the AEMIF
84	* because it is expected that there is only one user of a given
85	* chip-select.
86	*
87	* Returns 0 on success, else negative errno.
88	*/
89	int davinci_aemif_setup_timing(struct davinci_aemif_timing *t,
90	void __iomem *base, unsigned cs)
91	{
92	unsigned set, val;
12cdd3d7	93	int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup;
8060ef4d SN	94	unsigned offset = A1CR_OFFSET + cs * 4;
	95	struct clk *aemif_clk;
	96	unsigned long clkrate;
	97
	98	if (!t)
	99	return 0; /* Nothing to do */
	100
	101	aemif_clk = clk_get(NULL, "aemif");
	102	if (IS_ERR(aemif_clk))
	103	return PTR_ERR(aemif_clk);
	104
	105	clkrate = clk_get_rate(aemif_clk);
	106
	107	clkrate /= 1000; /* turn clock into kHz for ease of use */
	108
	109	ta = aemif_calc_rate(t->ta, clkrate, TA_MAX);
	110	rhold = aemif_calc_rate(t->rhold, clkrate, RHOLD_MAX);
	111	rstrobe = aemif_calc_rate(t->rstrobe, clkrate, RSTROBE_MAX);
	112	rsetup = aemif_calc_rate(t->rsetup, clkrate, RSETUP_MAX);
	113	whold = aemif_calc_rate(t->whold, clkrate, WHOLD_MAX);
	114	wstrobe = aemif_calc_rate(t->wstrobe, clkrate, WSTROBE_MAX);
	115	wsetup = aemif_calc_rate(t->wsetup, clkrate, WSETUP_MAX);
	116
	117	if (ta < 0 \|\| rhold < 0 \|\| rstrobe < 0 \|\| rsetup < 0 \|\|
	118	whold < 0 \|\| wstrobe < 0 \|\| wsetup < 0) {
	119	pr_err("%s: cannot get suitable timings\n", __func__);
	120	return -EINVAL;
	121	}
	122
	123	set = TA(ta) \| RHOLD(rhold) \| RSTROBE(rstrobe) \| RSETUP(rsetup) \|
	124	WHOLD(whold) \| WSTROBE(wstrobe) \| WSETUP(wsetup);
	125
	126	val = __raw_readl(base + offset);
	127	val &= ~TIMING_MASK;
	128	val \|= set;
	129	__raw_writel(val, base + offset);
	130
	131	return 0;
	132	}
	133	EXPORT_SYMBOL(davinci_aemif_setup_timing);