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