[vims.h] Versatile Instruction Memory System

Functions
void	VIMSConfigure (uint32_t ui32Base, bool bRoundRobin, bool bPrefetch)
	Configures the VIMS. More...
void	VIMSModeSet (uint32_t ui32Base, uint32_t ui32Mode)
	Set the operational mode of the VIMS. More...
uint32_t	VIMSModeGet (uint32_t ui32Base)
	Get the current operational mode of the VIMS. More...
void	VIMSModeSafeSet (uint32_t ui32Base, uint32_t ui32NewMode, bool blocking)
	Set the operational mode of the VIMS in a safe sequence. More...
static void	VIMSLineBufDisable (uint32_t ui32Base)
	Disable VIMS linebuffers. More...
static void	VIMSLineBufEnable (uint32_t ui32Base)
	Enable VIMS linebuffers. More...

Detailed Description

Function Documentation

void VIMSConfigure	(	uint32_t	ui32Base,
		bool	bRoundRobin,
		bool	bPrefetch
	)

Configures the VIMS.

This function sets general control settings of the VIMS system.

Note

The VIMS mode must be set using the VIMSModeSet() call.

Parameters

ui32Base	is the base address of the VIMS.
bRoundRobin	specifies the arbitration method. true : Round Robin arbitration between the two available read/write interfaces (i.e. Icode/Dcode and Sysbus) is to be used. false : Strict arbitration will be used, where Icode/Dcode is preferred over the Sysbus.
bPrefetch	specifies if prefetching is to be used. true : Cache is to prefetch tag data for the following address. false : No prefetch.

Returns

None

See also

VIMSModeSet()

{
    uint32_t ui32Reg;

    // Check the arguments.
    ASSERT(VIMSBaseValid(ui32Base));

    ui32Reg = HWREG(ui32Base + VIMS_O_CTL);
    ui32Reg &= ~(VIMS_CTL_PREF_EN | VIMS_CTL_ARB_CFG);
    if(bRoundRobin)
    {
        ui32Reg |= VIMS_CTL_ARB_CFG;
    }
    if(bPrefetch)
    {
        ui32Reg |= VIMS_CTL_PREF_EN;
    }

    // Set the Arbitration and prefetch mode.
    HWREG(ui32Base + VIMS_O_CTL) = ui32Reg;
}

static void VIMSLineBufDisable ( uint32_t  ui32Base )

inlinestatic

Disable VIMS linebuffers.

Linebuffers should only be disabled when attempting to update the flash, to ensure that the content of the buffers is not stale. As soon as flash is updated the linebuffers should be reenabled. Failing to enable will have a performance impact.

Parameters

ui32Base

is the base address of the VIMS.

Returns

None.

{
    // Disable line buffers
    HWREG(ui32Base + VIMS_O_CTL) |= VIMS_CTL_IDCODE_LB_DIS_M |
                                        VIMS_CTL_SYSBUS_LB_DIS_M;
}

static void VIMSLineBufEnable ( uint32_t  ui32Base )

inlinestatic

Enable VIMS linebuffers.

Linebuffers should only be disabled when attempting to update the flash, to ensure that the content of the buffers is not stale. As soon as flash is updated the linebuffers should be reenabled. Failing to enable will have a performance impact.

Parameters

ui32Base

is the base address of the VIMS.

Returns

None.

{
    // Enable linebuffers
    HWREG(ui32Base + VIMS_O_CTL) &= ~(VIMS_CTL_IDCODE_LB_DIS_M |
                                          VIMS_CTL_SYSBUS_LB_DIS_M);
}

uint32_t VIMSModeGet

(

uint32_t

ui32Base

)

Get the current operational mode of the VIMS.

This function returns the operational mode of the VIMS.

Parameters

ui32Base

is the base address of the VIMS.

Returns

Returns one of:

• VIMS_MODE_CHANGING
• VIMS_MODE_DISABLED (GPRAM enabled)
• VIMS_MODE_ENABLED (CACHE mode)
• VIMS_MODE_OFF

See also

VIMSModeSet()

Referenced by SysCtrlStandby(), and VIMSModeSafeSet().

{
    uint32_t ui32Reg;

    // Check the arguments.
    ASSERT(VIMSBaseValid(ui32Base));

    ui32Reg = HWREG(ui32Base + VIMS_O_STAT);
    if(ui32Reg & VIMS_STAT_MODE_CHANGING)
    {
        return (VIMS_MODE_CHANGING);
    }
    else
    {
        return (ui32Reg & VIMS_STAT_MODE_M);
    }
}

void VIMSModeSafeSet	(	uint32_t	ui32Base,
		uint32_t	ui32NewMode,
		bool	blocking
	)

Set the operational mode of the VIMS in a safe sequence.

This function sets the operational mode of the VIMS in a safe sequence

Upon reset the VIMS will be in VIMS_MODE_CHANGING mode. In this mode the VIMS will initialize the cache (GP) RAM (to all zeros). The GP RAM will not be operational (read/write will result in bus fault). The Cache will not be operational (read/write to flash will be uncached). After a short delay (approx. 1029 clock cycles) the VIMS will automatically switch mode to VIMS_MODE_DISABLED (GPRAM enabled).

In VIMS_MODE_DISABLED mode, the cache is disabled but the GP RAM is accessible: The GP RAM will be accessible. The Cache will not be operational. Reads from flash will be uncached. From this mode, the VIMS may be put in VIMS_MODE_ENABLED (CACHE mode).

In VIMS_MODE_ENABLED mode, the cache is enabled for USERCODE space. The GP RAM will not be operational (read/write will result in bus fault). The Cache will be operational for SYSCODE space. Reads from flash in USERCODE space will be uncached.

In VIMS_MODE_OFF the cache RAM is off to conserve power.

Note

The VIMS must be invalidated when switching mode. This is done by setting VIMS_MODE_OFF before setting any new mode. This is automatically handled in this function.

It is highly recommended that the VIMS is put in disabled mode before writing to flash, since the cache will not be updated nor invalidated by flash writes. The line buffers should also be disabled when updating the flash.

Access from System Bus is never cached. Only access through ICODE DCODE bus from the System CPU is cached.

Parameters

ui32Base	is the base address of the VIMS.
ui32NewMode	is the new operational mode: VIMS_MODE_DISABLED (GPRAM enabled) VIMS_MODE_ENABLED (CACHE mode) VIMS_MODE_OFF
blocking	shall be set to TRUE if further code execution shall be blocked (delayed) until mode change is completed.

Returns

None

See also

VIMSModeSet() and VIMSModeGet()

{
    uint32_t currentMode;

    // Check the arguments.
    ASSERT(VIMSBaseValid(ui32Base));
    ASSERT((ui32NewMode == VIMS_MODE_DISABLED)   ||
           (ui32NewMode == VIMS_MODE_ENABLED)    ||
           (ui32NewMode == VIMS_MODE_OFF));

    // Make sure that only the mode bits are set in the input parameter
    // (done just for security since it is critical to the code flow)
    ui32NewMode &= VIMS_CTL_MODE_M;

    // Wait for any pending change to complete and get current VIMS mode
    // (This is a blocking point but will typically only be a blocking point
    // only if mode is changed multiple times with blocking=0)
    do {
        currentMode = VIMSModeGet( ui32Base );
    } while ( currentMode == VIMS_MODE_CHANGING );

    // First check that it actually is a mode change request
    if ( ui32NewMode != currentMode ) {
        // Set new mode
        VIMSModeSet( ui32Base, ui32NewMode );

        // Wait for final mode change to complete - if blocking is requested
        if ( blocking ) {
            while ( HWREGBITW( VIMS_BASE + VIMS_O_STAT, VIMS_STAT_MODE_CHANGING_BITN )) {
                // Do nothing - wait for change to complete.
            }
        }
    }
}

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void VIMSModeSet	(	uint32_t	ui32Base,
		uint32_t	ui32Mode
	)

Set the operational mode of the VIMS.

This function sets the operational mode of the VIMS.

Upon reset the VIMS will be in VIMS_MODE_CHANGING mode. In this mode the VIMS will initialize the cache (GP) RAM (to all zeros). The GP RAM will not be operational (read/write will result in bus fault). The Cache will not be operational. Reads and writes to flash will be uncached. After a short delay (approx. 1029 clock cycles) the VIMS will automatically switch mode to VIMS_MODE_DISABLED (GPRAM enabled).

In VIMS_MODE_DISABLED mode, the cache is disabled but the GP RAM is accessible: The GP RAM will be accessible. The Cache will not be operational. Reads from flash will be uncached. From this mode, the VIMS may be put in VIMS_MODE_ENABLED (CACHE mode).

In VIMS_MODE_ENABLED mode, the cache is enabled for USERCODE space. The GP RAM will not be operational (read/write will result in bus fault). The Cache will be operational for SYSCODE space. Reads from flash in USERCODE space will be uncached.

In VIMS_MODE_OFF the cache RAM is off to conserve power.

Note

The VIMS must be invalidated when switching mode. This is done by setting VIMS_MODE_OFF before setting any new mode. This is automatically handled in VIMSModeSafeSet()

It is highly recommended that the VIMS is put in disabled mode before writing to flash, since the cache will not be updated nor invalidated by flash writes. The line buffers should also be disabled when updating the flash. Once VIMSModeSet() is used to set the VIMS in VIMS_MODE_CHANGING mode, the user should check using VIMSModeGet() when the mode switches to VIMS_MODE_DISABLED. Only when the mode has changed the cache has been completely invalidated.

Access from System Bus is never cached. Only access through ICODE DCODE bus from the System CPU is cached.

Parameters

ui32Base	is the base address of the VIMS.
ui32Mode	is the operational mode. VIMS_MODE_DISABLED (GPRAM enabled) VIMS_MODE_ENABLED (CACHE mode) VIMS_MODE_OFF

Returns

None

See also

VIMSModeGet() and VIMSModeSafeSet()

Referenced by SysCtrlStandby(), and VIMSModeSafeSet().

{
    uint32_t ui32Reg;

    // Check the arguments.
    ASSERT(VIMSBaseValid(ui32Base));

    ASSERT((ui32Mode == VIMS_MODE_DISABLED)   ||
           (ui32Mode == VIMS_MODE_ENABLED)    ||
           (ui32Mode == VIMS_MODE_OFF));

    // Set the mode.
    ui32Reg = HWREG(ui32Base + VIMS_O_CTL);
    ui32Reg &= ~VIMS_CTL_MODE_M;
    ui32Reg |= (ui32Mode & VIMS_CTL_MODE_M);

    HWREG(ui32Base + VIMS_O_CTL) = ui32Reg;
}

Macro Definition Documentation

#define VIMS_MODE_CHANGING   0x4

Referenced by SysCtrlStandby(), VIMSModeGet(), and VIMSModeSafeSet().

#define VIMS_MODE_DISABLED   (VIMS_CTL_MODE_GPRAM)

Referenced by VIMSModeSafeSet(), and VIMSModeSet().

#define VIMS_MODE_ENABLED   (VIMS_CTL_MODE_CACHE)

Referenced by SysCtrlStandby(), VIMSModeSafeSet(), and VIMSModeSet().

#define VIMS_MODE_OFF   (VIMS_CTL_MODE_OFF)

Referenced by SysCtrlStandby(), VIMSModeSafeSet(), and VIMSModeSet().