1/*
2 * MSDI IP block reset
3 *
4 * Copyright (C) 2012 Texas Instruments, Inc.
5 * Paul Walmsley
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * version 2 as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19 * 02110-1301 USA
20 *
21 * XXX What about pad muxing?
22 */
23
24#include <linux/kernel.h>
25#include <linux/err.h>
26#include <linux/platform_data/gpio-omap.h>
27
28#include "prm.h"
29#include "common.h"
30#include "control.h"
31#include "omap_hwmod.h"
32#include "omap_device.h"
33#include "mux.h"
34#include "mmc.h"
35
36/*
37 * MSDI_CON_OFFSET: offset in bytes of the MSDI IP block's CON register
38 *     from the IP block's base address
39 */
40#define MSDI_CON_OFFSET				0x0c
41
42/* Register bitfields in the CON register */
43#define MSDI_CON_POW_MASK			BIT(11)
44#define MSDI_CON_CLKD_MASK			(0x3f << 0)
45#define MSDI_CON_CLKD_SHIFT			0
46
47/* MSDI_TARGET_RESET_CLKD: clock divisor to use throughout the reset */
48#define MSDI_TARGET_RESET_CLKD		0x3ff
49
50/**
51 * omap_msdi_reset - reset the MSDI IP block
52 * @oh: struct omap_hwmod *
53 *
54 * The MSDI IP block on OMAP2420 has to have both the POW and CLKD
55 * fields set inside its CON register for a reset to complete
56 * successfully.  This is not documented in the TRM.  For CLKD, we use
57 * the value that results in the lowest possible clock rate, to attempt
58 * to avoid disturbing any cards.
59 */
60int omap_msdi_reset(struct omap_hwmod *oh)
61{
62	u16 v = 0;
63	int c = 0;
64
65	/* Write to the SOFTRESET bit */
66	omap_hwmod_softreset(oh);
67
68	/* Enable the MSDI core and internal clock */
69	v |= MSDI_CON_POW_MASK;
70	v |= MSDI_TARGET_RESET_CLKD << MSDI_CON_CLKD_SHIFT;
71	omap_hwmod_write(v, oh, MSDI_CON_OFFSET);
72
73	/* Poll on RESETDONE bit */
74	omap_test_timeout((omap_hwmod_read(oh, oh->class->sysc->syss_offs)
75			   & SYSS_RESETDONE_MASK),
76			  MAX_MODULE_SOFTRESET_WAIT, c);
77
78	if (c == MAX_MODULE_SOFTRESET_WAIT)
79		pr_warn("%s: %s: softreset failed (waited %d usec)\n",
80			__func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
81	else
82		pr_debug("%s: %s: softreset in %d usec\n", __func__,
83			 oh->name, c);
84
85	/* Disable the MSDI internal clock */
86	v &= ~MSDI_CON_CLKD_MASK;
87	omap_hwmod_write(v, oh, MSDI_CON_OFFSET);
88
89	return 0;
90}
91