msdi.c
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/*
* MSDI IP block reset
*
* Copyright (C) 2012 Texas Instruments, Inc.
* Paul Walmsley
*
* 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.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* XXX What about pad muxing?
*/
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/platform_data/gpio-omap.h>
#include "prm.h"
#include "common.h"
#include "control.h"
#include "omap_hwmod.h"
#include "omap_device.h"
#include "mux.h"
#include "mmc.h"
/*
* MSDI_CON_OFFSET: offset in bytes of the MSDI IP block's CON register
* from the IP block's base address
*/
#define MSDI_CON_OFFSET 0x0c
/* Register bitfields in the CON register */
#define MSDI_CON_POW_MASK BIT(11)
#define MSDI_CON_CLKD_MASK (0x3f << 0)
#define MSDI_CON_CLKD_SHIFT 0
/* MSDI_TARGET_RESET_CLKD: clock divisor to use throughout the reset */
#define MSDI_TARGET_RESET_CLKD 0x3ff
/**
* omap_msdi_reset - reset the MSDI IP block
* @oh: struct omap_hwmod *
*
* The MSDI IP block on OMAP2420 has to have both the POW and CLKD
* fields set inside its CON register for a reset to complete
* successfully. This is not documented in the TRM. For CLKD, we use
* the value that results in the lowest possible clock rate, to attempt
* to avoid disturbing any cards.
*/
int omap_msdi_reset(struct omap_hwmod *oh)
{
u16 v = 0;
int c = 0;
/* Write to the SOFTRESET bit */
omap_hwmod_softreset(oh);
/* Enable the MSDI core and internal clock */
v |= MSDI_CON_POW_MASK;
v |= MSDI_TARGET_RESET_CLKD << MSDI_CON_CLKD_SHIFT;
omap_hwmod_write(v, oh, MSDI_CON_OFFSET);
/* Poll on RESETDONE bit */
omap_test_timeout((omap_hwmod_read(oh, oh->class->sysc->syss_offs)
& SYSS_RESETDONE_MASK),
MAX_MODULE_SOFTRESET_WAIT, c);
if (c == MAX_MODULE_SOFTRESET_WAIT)
pr_warning("%s: %s: softreset failed (waited %d usec)\n",
__func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
else
pr_debug("%s: %s: softreset in %d usec\n", __func__,
oh->name, c);
/* Disable the MSDI internal clock */
v &= ~MSDI_CON_CLKD_MASK;
omap_hwmod_write(v, oh, MSDI_CON_OFFSET);
return 0;
}