[Q] how to disable/enable cache

[rudi ;-)]

edit/update:
have some things tried, but have no successfull with it


hi

caused to use same pins for sd card like flash, need to disable/enable cache.

found 4 (6) api for it in cache_utils.h

// Suspend the scheduler on both CPUs, disable cache.
// Contrary to its name this doesn't do anything with interrupts, yet.
// Interrupt disabling capability will be added once we implement
// interrupt allocation API.
void spi_flash_disable_interrupts_caches_and_other_cpu();

// Enable cache, enable interrupts (to be added in future), resume scheduler
void spi_flash_enable_interrupts_caches_and_other_cpu();

// Disables non-IRAM interrupt handlers on current CPU and caches on both CPUs.
// This function is implied to be called when other CPU is not running or running code from IRAM.
void spi_flash_disable_interrupts_caches_and_other_cpu_no_os();

// Enable cache, enable interrupts on current CPU.
// This function is implied to be called when other CPU is not running or running code from IRAM.
void spi_flash_enable_interrupts_caches_no_os();

also in cache_utils.c

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);

Code: Select all

/**
 * 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;

Code: Select all

static void IRAM_ATTR spi_flash_disable_cache(uint32_t cpuid, uint32_t* saved_state)
{
    uint32_t ret = 0;
    if (cpuid == 0) {
        ret |= GET_PERI_REG_BITS2(DPORT_PRO_CACHE_CTRL1_REG, cache_mask, 0);
        while (GET_PERI_REG_BITS2(DPORT_PRO_DCACHE_DBUG0_REG, DPORT_PRO_CACHE_STATE, DPORT_PRO_CACHE_STATE_S) != 1) {
            ;
        }
        SET_PERI_REG_BITS(DPORT_PRO_CACHE_CTRL_REG, 1, 0, DPORT_PRO_CACHE_ENABLE_S);
    } else {
        ret |= GET_PERI_REG_BITS2(DPORT_APP_CACHE_CTRL1_REG, cache_mask, 0);
        while (GET_PERI_REG_BITS2(DPORT_APP_DCACHE_DBUG0_REG, DPORT_APP_CACHE_STATE, DPORT_APP_CACHE_STATE_S) != 1) {
            ;
        }
        SET_PERI_REG_BITS(DPORT_APP_CACHE_CTRL_REG, 1, 0, DPORT_APP_CACHE_ENABLE_S);
    }
    *saved_state = ret;
}

Code: Select all

static void IRAM_ATTR spi_flash_restore_cache(uint32_t cpuid, uint32_t saved_state)
{
    if (cpuid == 0) {
        SET_PERI_REG_BITS(DPORT_PRO_CACHE_CTRL_REG, 1, 1, DPORT_PRO_CACHE_ENABLE_S);
        SET_PERI_REG_BITS(DPORT_PRO_CACHE_CTRL1_REG, cache_mask, saved_state, 0);
    } else {
        SET_PERI_REG_BITS(DPORT_APP_CACHE_CTRL_REG, 1, 1, DPORT_APP_CACHE_ENABLE_S);
        SET_PERI_REG_BITS(DPORT_APP_CACHE_CTRL1_REG, cache_mask, saved_state, 0);
    }
}

Q1: which API we need to use?

Q2: which value we need for parameter 2 for spi_flash_disable_cache in cache_utils.c ?

// Interrupt disabling capability will be added once we implement
// interrupt allocation API.

Q3: was this done just in time or do we missing this and nedd for parallel mode sd card/flash?

Cause i think, i am not alone with this, would be help if we get perhabs a sample on sd card
which used the same pins like flash.

In future mode after silicon rev0 - comes rev1 next days, we have more RAM / with PSRAM.
Does this affect / disturb later PSRAM ?

best wishes
rudi