esp-idf/components/esp32/include/soc/cpu.h

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// Copyright 2010-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef _SOC_CPU_H
#define _SOC_CPU_H
#include <stdint.h>
#include <stdbool.h>
#include <stddef.h>
#include "xtensa/corebits.h"
/* C macros for xtensa special register read/write/exchange */
#define RSR(reg, curval) asm volatile ("rsr %0, " #reg : "=r" (curval));
#define WSR(reg, newval) asm volatile ("wsr %0, " #reg : : "r" (newval));
#define XSR(reg, swapval) asm volatile ("xsr %0, " #reg : "+r" (swapval));
/* Return true if the CPU is in an interrupt context
(PS.UM == 0)
*/
static inline bool cpu_in_interrupt_context(void)
{
uint32_t ps;
RSR(PS, ps);
return (ps & PS_UM) == 0;
}
/* Functions to set page attributes for Region Protection option in the CPU.
* See Xtensa ISA Reference manual for explanation of arguments (section 4.6.3.2).
*/
static inline void cpu_write_dtlb(uint32_t vpn, unsigned attr)
{
asm volatile ("wdtlb %1, %0; dsync\n" :: "r" (vpn), "r" (attr));
}
static inline void cpu_write_itlb(unsigned vpn, unsigned attr)
{
asm volatile ("witlb %1, %0; isync\n" :: "r" (vpn), "r" (attr));
}
/* Make page 0 access raise an exception.
* Also protect some other unused pages so we can catch weirdness.
* Useful attribute values:
* 0 cached, RW
* 2 bypass cache, RWX (default value after CPU reset)
* 15 no access, raise exception
*/
static inline void cpu_configure_region_protection()
{
const uint32_t pages_to_protect[] = {0x00000000, 0x80000000, 0xa0000000, 0xc0000000, 0xe0000000};
for (int i = 0; i < sizeof(pages_to_protect)/sizeof(pages_to_protect[0]); ++i) {
cpu_write_dtlb(pages_to_protect[i], 0xf);
cpu_write_itlb(pages_to_protect[i], 0xf);
}
cpu_write_dtlb(0x20000000, 0);
cpu_write_itlb(0x20000000, 0);
}
/*
* @brief Set CPU frequency to the value defined in menuconfig
*
* Called from cpu_start.c, not intended to be called from other places.
* This is a temporary function which will be replaced once dynamic
* CPU frequency changing is implemented.
*/
void esp_set_cpu_freq(void);
#endif