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// SPDX-License-Identifier: GPL-2.0+
/*
* Cortex-R Memory Protection Unit specific code
*
* Copyright (C) 2018 Texas Instruments Incorporated - https://www.ti.com/
* Lokesh Vutla <lokeshvutla@ti.com>
*/
#include <command.h>
#include <cpu_func.h>
#include <asm/armv7.h>
#include <asm/system.h>
#include <asm/barriers.h>
#include <linux/bitops.h>
#include <linux/compiler.h>
#include <asm/armv7_mpu.h>
/* MPU Type register definitions */
#define MPUIR_S_SHIFT 0
#define MPUIR_S_MASK BIT(MPUIR_S_SHIFT)
#define MPUIR_DREGION_SHIFT 8
#define MPUIR_DREGION_MASK (0xff << 8)
/**
* Note:
* The Memory Protection Unit(MPU) allows to partition memory into regions
* and set individual protection attributes for each region. In absence
* of MPU a default map[1] will take effect. make sure to run this code
* from a region which has execution permissions by default.
* [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0460d/I1002400.html
*/
void disable_mpu(void)
{
u32 reg;
reg = get_cr();
reg &= ~CR_M;
dsb();
set_cr(reg);
isb();
}
void enable_mpu(void)
{
u32 reg;
reg = get_cr();
reg |= CR_M;
dsb();
set_cr(reg);
isb();
}
int mpu_enabled(void)
{
return get_cr() & CR_M;
}
void mpu_config(struct mpu_region_config *rgn)
{
u32 attr, val;
attr = get_attr_encoding(rgn->mr_attr);
/* MPU Region Number Register */
asm volatile ("mcr p15, 0, %0, c6, c2, 0" : : "r" (rgn->region_no));
/* MPU Region Base Address Register */
asm volatile ("mcr p15, 0, %0, c6, c1, 0" : : "r" (rgn->start_addr));
/* MPU Region Size and Enable Register */
if (rgn->reg_size)
val = (rgn->reg_size << REGION_SIZE_SHIFT) | ENABLE_REGION;
else
val = DISABLE_REGION;
asm volatile ("mcr p15, 0, %0, c6, c1, 2" : : "r" (val));
/* MPU Region Access Control Register */
val = rgn->xn << XN_SHIFT | rgn->ap << AP_SHIFT | attr;
asm volatile ("mcr p15, 0, %0, c6, c1, 4" : : "r" (val));
}
void setup_mpu_regions(struct mpu_region_config *rgns, u32 num_rgns)
{
u32 num, i;
asm volatile ("mrc p15, 0, %0, c0, c0, 4" : "=r" (num));
num = (num & MPUIR_DREGION_MASK) >> MPUIR_DREGION_SHIFT;
/* Regions to be configured cannot be greater than available regions */
if (num < num_rgns)
num_rgns = num;
/**
* Assuming dcache might not be enabled at this point, disabling
* and invalidating only icache.
*/
icache_disable();
invalidate_icache_all();
disable_mpu();
for (i = 0; i < num_rgns; i++)
mpu_config(&rgns[i]);
enable_mpu();
icache_enable();
}
void enable_caches(void)
{
/*
* setup_mpu_regions() might have enabled Icache. So add a check
* before enabling Icache
*/
if (!icache_status())
icache_enable();
dcache_enable();
}
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