topic Re: iMX SDRAM controller enter manual self-refresh? (ENGcm1238) in i.MX Processors

iMX SDRAM controller enter manual self-refresh? (ENGcm1238)

andrew_questps — Tue, 06 Aug 2013 00:24:44 GMT

I am attempting to place an iMX25 SDRAM into manual self-refresh mode, reset the PLL and then set the SDRAM controller back into normal mode.

As soon as I attempt to place the SDRAM controller into manual-self refresh the CPU locks up and the watchdog resets the device.

Here is the code I am using:

LEAF_ENTRY OALCPUEnterSuspend

    mov     r0,#0
    mcr     p15, 0, r0, c7, c0, 4               ; Enter WFI

    ; Exit Wait For Interrupt set SDRAM to manual self-refresh
    ldr     r1, =CSP_BASE_REG_PA_ESDCTL
    ldr     r2, =CSP_BASE_MEM_PA_CSD0

    ; Set precharge command
    ldr     r0, =0x93118880
    str     r0, [r1, #ESDRAMC_ESDCTL0_OFFSET]

    ; Access SDRAM with A10 high to precharge all banks
    ldr     r0, =0x0
    strb    r0, [r2, #0x400]

    ; Set manual refresh command
    ldr     r0, =0xC3118880
    str     r0, [r1, #ESDRAMC_ESDCTL0_OFFSET]

    ; Wait for more than 400 us
    ldr     r3, =0x20000
wait
    subs    r3, r3, #1
    bne     wait

    ; Configure Clock Control Register
    ;   Configure ARM and AHB Clock
    ;
    ;   ARM Clock 399Mhz = MCUPLL * DIVGEN / ARM_DIVIDER
    ;                    = 532Mhz * 0.75   / 1
    ;                    = 399 Mhz
    ;       ARM_DIVIDER (0 << 30)   = 0x00000000
    ;       ARM_SRC     (1 << 14)   = 0x00004000
    ;
    ;   AHB Clock 133Mhz = ARMCLK / AHB_DIVIDER
    ;                    = 399Mhz / 3
    ;                    = 133 Mhz
    ;       AHB_DIVIDER (2 << 28)   = 0x20000000
    ;
    ;   USB Clock 60Mhz =  UPLL  / USB_DIVIDER
    ;                   = 240Mhz / 4
    ;                   = 60Mhz
    ;       USB_DIVIDER (3 << 16)   = 0x00030000
    ;
    ;   USB PLL Enable (0 << 23)    = 0x00000000
    ;   MPLL and UPLL reset (3<<26) = 0x0C000000
    ;   LP CTL (0<<24)              = 0x00000000
    ;                               -------------
    ;                                 0x2C034000
    ldr     r0, =0x2C034000

    ldr     r4, =10000

    ; Wait PLL statibilisation
waitClock
    sub r4, r4, #1
    cmp r4, #0
    bne waitClock

    ; Now wait the MPLL is reset, so wait on the MPLL lock bit
WaitForMPLL
    ldr     r0, [r1, #CRM_MPCTL_OFFSET]
    tst     r0, #MPLL_LOCK_FLAG
    beq     WaitForMPLL

    ; Now wait the UPLL is reset, so wait on the UPLL lock bit
WaitForUPLL
    ldr     r0, [r1, #CRM_UPCTL_OFFSET]
    tst     r0, #UPLL_LOCK_FLAG
    beq     WaitForUPLL
   
    ; Set normal mode command
    ldr     r0, =0x83218880
    str     r0, [r1, #ESDRAMC_ESDCTL0_OFFSET]

    RETURN

    LEAF_ENTRY OALCPUEnterSuspend_sz
    ;Entry used to calculate the size of the function
    nop
    nop
    ENTRY_END

    END

Does anyone know what I need to change to get this working?

Cheers,

Andre

Re: iMX SDRAM controller enter manual self-refresh? (ENGcm1238)

JerryFan — Tue, 06 Aug 2013 01:37:25 GMT

Just a reminder： the code was expected running on some non-SDRAM memory, such as internal ram or cache.

Re: Re: iMX SDRAM controller enter manual self-refresh? (ENGcm1238)

andrew_questps — Tue, 06 Aug 2013 02:06:57 GMT

Chongbin Fan wrote:

Just a reminder： the code was expected running on some non-SDRAM memory, such as internal ram or cache.

I know I am doing the following in power.c

VOID OALCPUPowerOff(void)
{
    void (*suspend_func_ptr)();
    int suspend_func_size;
....
    // Need to keep the following clocks gated on for successful handshake
....
    // copy the suspend routine into IRAM
    suspend_func_ptr = (void*)OALPAtoCA(IMAGE_WINCE_IRAM_PA_START);
    suspend_func_size = (UINT32)OALCPUEnterSuspend_sz - (UINT32)OALCPUEnterSuspend + 256;  //include constants
    memcpy(suspend_func_ptr, OALCPUEnterSuspend, suspend_func_size );

    // Enter wait-for-interrupt mode and the system will transition
    // to the low-power mode configured in the CCMR above.
    // OALCPUEnterWFI();
    suspend_func_ptr();

    // exiting suspend
    if (dwSdmaStat)
    {
        OUTREG32(&g_pSDMA->HSTART, dwSdmaStat);
    }
}

If I comment out the rest of the code except for the two lines:

mov r0,#0

mcr p15, 0, r0, c7, c0, 4 ; Enter WFI

and return it works OK, it's only when I attempt to access any of the SDRAM control registers.

Re: iMX SDRAM controller enter manual self-refresh? (ENGcm1238)

JerryFan — Tue, 06 Aug 2013 04:25:01 GMT

"it's only when I attempt to access any of the SDRAM control registers."

Please make sure 256 is big enough to consisted of the "CSP_BASE_REG_PA_ESDCTL" stuff which was expected at the end of the function, but not sure. You can dump the image and double check.