esp-idf/components/spi_flash/cache_utils.c

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2016-08-17 11:08:22 -04:00
// Copyright 2015-2016 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
//
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// 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.
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <stdio.h>
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#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include <freertos/semphr.h>
#include <esp32/rom/spi_flash.h>
#include <esp32/rom/cache.h>
#include <soc/soc.h>
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#include <soc/dport_reg.h>
#include "sdkconfig.h"
#include "esp_ipc.h"
#include "esp_attr.h"
#include "esp_intr_alloc.h"
#include "esp_spi_flash.h"
#include "esp_log.h"
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static void IRAM_ATTR spi_flash_disable_cache(uint32_t cpuid, uint32_t* saved_state);
static void IRAM_ATTR spi_flash_restore_cache(uint32_t cpuid, uint32_t saved_state);
static uint32_t s_flash_op_cache_state[2];
#ifndef CONFIG_FREERTOS_UNICORE
static SemaphoreHandle_t s_flash_op_mutex;
static volatile bool s_flash_op_can_start = false;
static volatile bool s_flash_op_complete = false;
#ifndef NDEBUG
static volatile int s_flash_op_cpu = -1;
#endif
void spi_flash_init_lock()
{
s_flash_op_mutex = xSemaphoreCreateRecursiveMutex();
assert(s_flash_op_mutex != NULL);
}
void spi_flash_op_lock()
{
xSemaphoreTakeRecursive(s_flash_op_mutex, portMAX_DELAY);
}
void spi_flash_op_unlock()
{
xSemaphoreGiveRecursive(s_flash_op_mutex);
}
/*
If you're going to modify this, keep in mind that while the flash caches of the pro and app
cpu are separate, the psram cache is *not*. If one of the CPUs returns from a flash routine
with its cache enabled but the other CPUs cache is not enabled yet, you will have problems
when accessing psram from the former CPU.
*/
void IRAM_ATTR spi_flash_op_block_func(void* arg)
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{
// Disable scheduler on this CPU
vTaskSuspendAll();
// Restore interrupts that aren't located in IRAM
esp_intr_noniram_disable();
uint32_t cpuid = (uint32_t) arg;
// s_flash_op_complete flag is cleared on *this* CPU, otherwise the other
// CPU may reset the flag back to false before IPC task has a chance to check it
// (if it is preempted by an ISR taking non-trivial amount of time)
s_flash_op_complete = false;
s_flash_op_can_start = true;
while (!s_flash_op_complete) {
// busy loop here and wait for the other CPU to finish flash operation
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}
// Flash operation is complete, re-enable cache
spi_flash_restore_cache(cpuid, s_flash_op_cache_state[cpuid]);
// Restore interrupts that aren't located in IRAM
esp_intr_noniram_enable();
// Re-enable scheduler
xTaskResumeAll();
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}
void IRAM_ATTR spi_flash_disable_interrupts_caches_and_other_cpu()
{
spi_flash_op_lock();
const uint32_t cpuid = xPortGetCoreID();
const uint32_t other_cpuid = (cpuid == 0) ? 1 : 0;
#ifndef NDEBUG
// For sanity check later: record the CPU which has started doing flash operation
assert(s_flash_op_cpu == -1);
s_flash_op_cpu = cpuid;
#endif
if (xTaskGetSchedulerState() == taskSCHEDULER_NOT_STARTED) {
// Scheduler hasn't been started yet, it means that spi_flash API is being
// called from the 2nd stage bootloader or from user_start_cpu0, i.e. from
// PRO CPU. APP CPU is either in reset or spinning inside user_start_cpu1,
// which is in IRAM. So it is safe to disable cache for the other_cpuid here.
assert(other_cpuid == 1);
spi_flash_disable_cache(other_cpuid, &s_flash_op_cache_state[other_cpuid]);
} else {
// Temporarily raise current task priority to prevent a deadlock while
// waiting for IPC task to start on the other CPU
int old_prio = uxTaskPriorityGet(NULL);
vTaskPrioritySet(NULL, configMAX_PRIORITIES - 1);
// Signal to the spi_flash_op_block_task on the other CPU that we need it to
// disable cache there and block other tasks from executing.
s_flash_op_can_start = false;
esp_err_t ret = esp_ipc_call(other_cpuid, &spi_flash_op_block_func, (void*) other_cpuid);
assert(ret == ESP_OK);
while (!s_flash_op_can_start) {
// Busy loop and wait for spi_flash_op_block_func to disable cache
// on the other CPU
}
// Disable scheduler on the current CPU
vTaskSuspendAll();
// Can now set the priority back to the normal one
vTaskPrioritySet(NULL, old_prio);
// This is guaranteed to run on CPU <cpuid> because the other CPU is now
// occupied by highest priority task
assert(xPortGetCoreID() == cpuid);
}
// Kill interrupts that aren't located in IRAM
esp_intr_noniram_disable();
// This CPU executes this routine, with non-IRAM interrupts and the scheduler
// disabled. The other CPU is spinning in the spi_flash_op_block_func task, also
// with non-iram interrupts and the scheduler disabled. None of these CPUs will
// touch external RAM or flash this way, so we can safely disable caches.
spi_flash_disable_cache(cpuid, &s_flash_op_cache_state[cpuid]);
spi_flash_disable_cache(other_cpuid, &s_flash_op_cache_state[other_cpuid]);
}
void IRAM_ATTR spi_flash_enable_interrupts_caches_and_other_cpu()
{
const uint32_t cpuid = xPortGetCoreID();
const uint32_t other_cpuid = (cpuid == 0) ? 1 : 0;
#ifndef NDEBUG
// Sanity check: flash operation ends on the same CPU as it has started
assert(cpuid == s_flash_op_cpu);
// More sanity check: if scheduler isn't started, only CPU0 can call this.
assert(!(xTaskGetSchedulerState() == taskSCHEDULER_NOT_STARTED && cpuid != 0));
s_flash_op_cpu = -1;
#endif
// Re-enable cache on both CPUs. After this, cache (flash and external RAM) should work again.
spi_flash_restore_cache(cpuid, s_flash_op_cache_state[cpuid]);
spi_flash_restore_cache(other_cpuid, s_flash_op_cache_state[other_cpuid]);
if (xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) {
// Signal to spi_flash_op_block_task that flash operation is complete
s_flash_op_complete = true;
}
// Re-enable non-iram interrupts
esp_intr_noniram_enable();
// Resume tasks on the current CPU, if the scheduler has started.
// NOTE: enabling non-IRAM interrupts has to happen before this,
// because once the scheduler has started, due to preemption the
// current task can end up being moved to the other CPU.
// But esp_intr_noniram_enable has to be called on the same CPU which
// called esp_intr_noniram_disable
if (xTaskGetSchedulerState() != taskSCHEDULER_NOT_STARTED) {
xTaskResumeAll();
}
// Release API lock
spi_flash_op_unlock();
}
void IRAM_ATTR spi_flash_disable_interrupts_caches_and_other_cpu_no_os()
{
const uint32_t cpuid = xPortGetCoreID();
const uint32_t other_cpuid = (cpuid == 0) ? 1 : 0;
// do not care about other CPU, it was halted upon entering panic handler
spi_flash_disable_cache(other_cpuid, &s_flash_op_cache_state[other_cpuid]);
// Kill interrupts that aren't located in IRAM
esp_intr_noniram_disable();
// Disable cache on this CPU as well
spi_flash_disable_cache(cpuid, &s_flash_op_cache_state[cpuid]);
}
void IRAM_ATTR spi_flash_enable_interrupts_caches_no_os()
{
const uint32_t cpuid = xPortGetCoreID();
// Re-enable cache on this CPU
spi_flash_restore_cache(cpuid, s_flash_op_cache_state[cpuid]);
// Re-enable non-iram interrupts
esp_intr_noniram_enable();
}
#else // CONFIG_FREERTOS_UNICORE
void spi_flash_init_lock()
{
}
void spi_flash_op_lock()
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{
vTaskSuspendAll();
}
void spi_flash_op_unlock()
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{
xTaskResumeAll();
}
void IRAM_ATTR spi_flash_disable_interrupts_caches_and_other_cpu()
{
spi_flash_op_lock();
esp_intr_noniram_disable();
spi_flash_disable_cache(0, &s_flash_op_cache_state[0]);
}
void IRAM_ATTR spi_flash_enable_interrupts_caches_and_other_cpu()
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{
spi_flash_restore_cache(0, s_flash_op_cache_state[0]);
esp_intr_noniram_enable();
spi_flash_op_unlock();
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}
void IRAM_ATTR spi_flash_disable_interrupts_caches_and_other_cpu_no_os()
{
// Kill interrupts that aren't located in IRAM
esp_intr_noniram_disable();
// Disable cache on this CPU as well
spi_flash_disable_cache(0, &s_flash_op_cache_state[0]);
}
void IRAM_ATTR spi_flash_enable_interrupts_caches_no_os()
{
// Re-enable cache on this CPU
spi_flash_restore_cache(0, s_flash_op_cache_state[0]);
// Re-enable non-iram interrupts
esp_intr_noniram_enable();
}
#endif // CONFIG_FREERTOS_UNICORE
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/**
* The following two functions are replacements for Cache_Read_Disable and Cache_Read_Enable
* function in ROM. They are used to work around a bug where Cache_Read_Disable requires a call to
* Cache_Flush before Cache_Read_Enable, even if cached data was not modified.
*/
static const uint32_t cache_mask = DPORT_APP_CACHE_MASK_OPSDRAM | DPORT_APP_CACHE_MASK_DROM0 |
DPORT_APP_CACHE_MASK_DRAM1 | DPORT_APP_CACHE_MASK_IROM0 |
DPORT_APP_CACHE_MASK_IRAM1 | DPORT_APP_CACHE_MASK_IRAM0;
static void IRAM_ATTR spi_flash_disable_cache(uint32_t cpuid, uint32_t* saved_state)
{
uint32_t ret = 0;
if (cpuid == 0) {
ret |= DPORT_GET_PERI_REG_BITS2(DPORT_PRO_CACHE_CTRL1_REG, cache_mask, 0);
while (DPORT_GET_PERI_REG_BITS2(DPORT_PRO_DCACHE_DBUG0_REG, DPORT_PRO_CACHE_STATE, DPORT_PRO_CACHE_STATE_S) != 1) {
;
}
DPORT_SET_PERI_REG_BITS(DPORT_PRO_CACHE_CTRL_REG, 1, 0, DPORT_PRO_CACHE_ENABLE_S);
} else {
ret |= DPORT_GET_PERI_REG_BITS2(DPORT_APP_CACHE_CTRL1_REG, cache_mask, 0);
while (DPORT_GET_PERI_REG_BITS2(DPORT_APP_DCACHE_DBUG0_REG, DPORT_APP_CACHE_STATE, DPORT_APP_CACHE_STATE_S) != 1) {
;
}
DPORT_SET_PERI_REG_BITS(DPORT_APP_CACHE_CTRL_REG, 1, 0, DPORT_APP_CACHE_ENABLE_S);
}
*saved_state = ret;
}
static void IRAM_ATTR spi_flash_restore_cache(uint32_t cpuid, uint32_t saved_state)
{
if (cpuid == 0) {
DPORT_SET_PERI_REG_BITS(DPORT_PRO_CACHE_CTRL_REG, 1, 1, DPORT_PRO_CACHE_ENABLE_S);
DPORT_SET_PERI_REG_BITS(DPORT_PRO_CACHE_CTRL1_REG, cache_mask, saved_state, 0);
} else {
DPORT_SET_PERI_REG_BITS(DPORT_APP_CACHE_CTRL_REG, 1, 1, DPORT_APP_CACHE_ENABLE_S);
DPORT_SET_PERI_REG_BITS(DPORT_APP_CACHE_CTRL1_REG, cache_mask, saved_state, 0);
}
}
IRAM_ATTR bool spi_flash_cache_enabled()
{
bool result = (DPORT_REG_GET_BIT(DPORT_PRO_CACHE_CTRL_REG, DPORT_PRO_CACHE_ENABLE) != 0);
#if portNUM_PROCESSORS == 2
result = result && (DPORT_REG_GET_BIT(DPORT_APP_CACHE_CTRL_REG, DPORT_APP_CACHE_ENABLE) != 0);
#endif
return result;
}