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/*
* OMAP4 PRM module functions
*
* Copyright (C) 2010 Texas Instruments, Inc.
* Copyright (C) 2010 Nokia Corporation
* Benoît Cousson
* 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.
*/
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <plat/common.h>
#include <plat/cpu.h>
#include <plat/prcm.h>
#include "prm44xx.h"
#include "prm-regbits-44xx.h"
/*
* Address offset (in bytes) between the reset control and the reset
* status registers: 4 bytes on OMAP4
*/
#define OMAP4_RST_CTRL_ST_OFFSET 4
/**
* omap4_prm_is_hardreset_asserted - read the HW reset line state of
* submodules contained in the hwmod module
* @rstctrl_reg: RM_RSTCTRL register address for this module
* @shift: register bit shift corresponding to the reset line to check
*
* Returns 1 if the (sub)module hardreset line is currently asserted,
* 0 if the (sub)module hardreset line is not currently asserted, or
* -EINVAL upon parameter error.
*/
int omap4_prm_is_hardreset_asserted(void __iomem *rstctrl_reg, u8 shift)
{
if (!cpu_is_omap44xx() || !rstctrl_reg)
return -EINVAL;
return omap4_prm_read_bits_shift(rstctrl_reg, (1 << shift));
}
/**
* omap4_prm_assert_hardreset - assert the HW reset line of a submodule
* @rstctrl_reg: RM_RSTCTRL register address for this module
* @shift: register bit shift corresponding to the reset line to assert
*
* Some IPs like dsp, ipu or iva contain processors that require an HW
* reset line to be asserted / deasserted in order to fully enable the
* IP. These modules may have multiple hard-reset lines that reset
* different 'submodules' inside the IP block. This function will
* place the submodule into reset. Returns 0 upon success or -EINVAL
* upon an argument error.
*/
int omap4_prm_assert_hardreset(void __iomem *rstctrl_reg, u8 shift)
{
u32 mask;
if (!cpu_is_omap44xx() || !rstctrl_reg)
return -EINVAL;
mask = 1 << shift;
omap4_prm_rmw_reg_bits(mask, mask, rstctrl_reg);
return 0;
}
/**
* omap4_prm_deassert_hardreset - deassert a submodule hardreset line and wait
* @rstctrl_reg: RM_RSTCTRL register address for this module
* @shift: register bit shift corresponding to the reset line to deassert
*
* Some IPs like dsp, ipu or iva contain processors that require an HW
* reset line to be asserted / deasserted in order to fully enable the
* IP. These modules may have multiple hard-reset lines that reset
* different 'submodules' inside the IP block. This function will
* take the submodule out of reset and wait until the PRCM indicates
* that the reset has completed before returning. Returns 0 upon success or
* -EINVAL upon an argument error, -EEXIST if the submodule was already out
* of reset, or -EBUSY if the submodule did not exit reset promptly.
*/
int omap4_prm_deassert_hardreset(void __iomem *rstctrl_reg, u8 shift)
{
u32 mask;
void __iomem *rstst_reg;
int c;
if (!cpu_is_omap44xx() || !rstctrl_reg)
return -EINVAL;
rstst_reg = rstctrl_reg + OMAP4_RST_CTRL_ST_OFFSET;
mask = 1 << shift;
/* Check the current status to avoid de-asserting the line twice */
if (omap4_prm_read_bits_shift(rstctrl_reg, mask) == 0)
return -EEXIST;
/* Clear the reset status by writing 1 to the status bit */
omap4_prm_rmw_reg_bits(0xffffffff, mask, rstst_reg);
/* de-assert the reset control line */
omap4_prm_rmw_reg_bits(mask, 0, rstctrl_reg);
/* wait the status to be set */
omap_test_timeout(omap4_prm_read_bits_shift(rstst_reg, mask),
MAX_MODULE_HARDRESET_WAIT, c);
return (c == MAX_MODULE_HARDRESET_WAIT) ? -EBUSY : 0;
}
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