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79 lines
2.8 KiB
C
79 lines
2.8 KiB
C
/*
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* SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include "soc/dport_reg.h"
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#include "esp_attr.h"
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#include "esp_psram.h"
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#include "esp_private/esp_psram_extram.h"
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#if CONFIG_FREERTOS_UNICORE
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#define PSRAM_MODE PSRAM_VADDR_MODE_NORMAL
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#else
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#define PSRAM_MODE PSRAM_VADDR_MODE_LOWHIGH
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#endif
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/*
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Before flushing the cache, if psram is enabled as a memory-mapped thing, we need to write back the data in the cache to the psram first,
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otherwise it will get lost. For now, we just read 64/128K of random PSRAM memory to do this.
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Note that this routine assumes some unique mapping for the first 2 banks of the PSRAM memory range, as well as the
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2 banks after the 2 MiB mark.
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*/
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void IRAM_ATTR esp_psram_extram_writeback_cache(void)
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{
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int x;
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volatile int i=0;
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volatile uint8_t *psram=(volatile uint8_t*)SOC_EXTRAM_DATA_LOW;
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int cache_was_disabled=0;
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if (!esp_psram_is_initialized()) return;
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//We need cache enabled for this to work. Re-enable it if needed; make sure we
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//disable it again on exit as well.
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if (DPORT_REG_GET_BIT(DPORT_PRO_CACHE_CTRL_REG, DPORT_PRO_CACHE_ENABLE)==0) {
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cache_was_disabled|=(1<<0);
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DPORT_SET_PERI_REG_BITS(DPORT_PRO_CACHE_CTRL_REG, 1, 1, DPORT_PRO_CACHE_ENABLE_S);
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}
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#ifndef CONFIG_FREERTOS_UNICORE
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if (DPORT_REG_GET_BIT(DPORT_APP_CACHE_CTRL_REG, DPORT_APP_CACHE_ENABLE)==0) {
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cache_was_disabled|=(1<<1);
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DPORT_SET_PERI_REG_BITS(DPORT_APP_CACHE_CTRL_REG, 1, 1, DPORT_APP_CACHE_ENABLE_S);
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}
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#endif
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#if (PSRAM_MODE != PSRAM_VADDR_MODE_LOWHIGH)
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/*
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Single-core and even/odd mode only have 32K of cache evenly distributed over the address lines. We can clear
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the cache by just reading 64K worth of cache lines.
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*/
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for (x=0; x<1024*64; x+=32) {
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i+=psram[x];
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}
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#else
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/*
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Low/high psram cache mode uses one 32K cache for the lowest 2MiB of SPI flash and another 32K for the highest
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2MiB. Clear this by reading from both regions.
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Note: this assumes the amount of external RAM is >2M. If it is 2M or less, what this code does is undefined. If
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we ever support external RAM chips of 2M or smaller, this may need adjusting.
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*/
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for (x=0; x<1024*64; x+=32) {
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i+=psram[x];
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i+=psram[x+(1024*1024*2)];
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}
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#endif
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if (cache_was_disabled&(1<<0)) {
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while (DPORT_GET_PERI_REG_BITS2(DPORT_PRO_DCACHE_DBUG0_REG, DPORT_PRO_CACHE_STATE, DPORT_PRO_CACHE_STATE_S) != 1) ;
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DPORT_SET_PERI_REG_BITS(DPORT_PRO_CACHE_CTRL_REG, 1, 0, DPORT_PRO_CACHE_ENABLE_S);
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}
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#ifndef CONFIG_FREERTOS_UNICORE
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if (cache_was_disabled&(1<<1)) {
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while (DPORT_GET_PERI_REG_BITS2(DPORT_APP_DCACHE_DBUG0_REG, DPORT_APP_CACHE_STATE, DPORT_APP_CACHE_STATE_S) != 1);
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DPORT_SET_PERI_REG_BITS(DPORT_APP_CACHE_CTRL_REG, 1, 0, DPORT_APP_CACHE_ENABLE_S);
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}
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#endif
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}
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