linux/drivers/soc/mediatek/mtk-infracfg.c

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/*
* Copyright (c) 2015 Pengutronix, Sascha Hauer <kernel@pengutronix.de>
*
* 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.
*/
#include <linux/export.h>
#include <linux/jiffies.h>
#include <linux/regmap.h>
#include <linux/soc/mediatek/infracfg.h>
#include <asm/processor.h>
#define INFRA_TOPAXI_PROTECTEN 0x0220
#define INFRA_TOPAXI_PROTECTSTA1 0x0228
#define INFRA_TOPAXI_PROTECTEN_SET 0x0260
#define INFRA_TOPAXI_PROTECTEN_CLR 0x0264
/**
* mtk_infracfg_set_bus_protection - enable bus protection
* @regmap: The infracfg regmap
* @mask: The mask containing the protection bits to be enabled.
* @reg_update: The boolean flag determines to set the protection bits
* by regmap_update_bits with enable register(PROTECTEN) or
* by regmap_write with set register(PROTECTEN_SET).
*
* This function enables the bus protection bits for disabled power
* domains so that the system does not hang when some unit accesses the
* bus while in power down.
*/
int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask,
bool reg_update)
{
unsigned long expired;
u32 val;
int ret;
if (reg_update)
regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask,
mask);
else
regmap_write(infracfg, INFRA_TOPAXI_PROTECTEN_SET, mask);
expired = jiffies + HZ;
while (1) {
ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
if (ret)
return ret;
if ((val & mask) == mask)
break;
cpu_relax();
if (time_after(jiffies, expired))
return -EIO;
}
return 0;
}
/**
* mtk_infracfg_clear_bus_protection - disable bus protection
* @regmap: The infracfg regmap
* @mask: The mask containing the protection bits to be disabled.
* @reg_update: The boolean flag determines to clear the protection bits
* by regmap_update_bits with enable register(PROTECTEN) or
* by regmap_write with clear register(PROTECTEN_CLR).
*
* This function disables the bus protection bits previously enabled with
* mtk_infracfg_set_bus_protection.
*/
int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask,
bool reg_update)
{
unsigned long expired;
int ret;
if (reg_update)
regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, 0);
else
regmap_write(infracfg, INFRA_TOPAXI_PROTECTEN_CLR, mask);
expired = jiffies + HZ;
while (1) {
u32 val;
ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
if (ret)
return ret;
if (!(val & mask))
break;
cpu_relax();
if (time_after(jiffies, expired))
return -EIO;
}
return 0;
}