Interrupt -Layer Initialisation

In first phase -initialisation

During first phase initialisation of start-up, the -kernel calls the ASSP's implementation of Asic::Init1(). -For the template reference board, where the ASSP is split into a common, ASSP -layer and a device-specific (variant) layer, interrupt handling is initialised -in the ASSP layer, specifically in TemplateAssp::Init1(), -defined in ...\template_assp\template_assp_priv.h, and -implemented in ...\template_assp\assp.cpp.

Note -that interrupts are disabled during first phase initialisation.

Within -your implementation of Init1(), do the following:

Initialise the ISR table.

It is useful to initialise the ISR table so -that each interrupt is bound, by default, to the Spurious interrupts handler, with the 32-bit parameter taking the -interrupt number.

For example,
... -const TInt KInterruptSourceCount = 32; -SInterruptHandler IsrHandlers[KInterruptSourceCount]; -... - -for( TInt i = 0; i < KInterruptSourceCount; ++i ) - { - IsrHandlers[i].iIsr = SpuriousHandler; - IsrHandlers[i].iPtr = (TAny*)i; - }
where the spurious interrupt handler function might be -implemented as:
void SpuriousHandler(TAny* aId) - { - Kern::Fault("SpuriousInt", (TInt)aId); // handle unexpected interrupt. - } -
On the template reference board, the ISR table is initialised -by TemplateInterrupt::Init1() in ...\template_assp\interrupts.cpp, -and this is called by TemplateAssp::Init1().
Register the dispatcher -functions. The Symbian platform kernel needs to know the location of the IRQ -and FIQ dispatchers. It provides the two functions: Arm::SetIrqHandler() and Arm::SetFiqHandler(), -which the Variant layer must call, passing the addresses of the IRQ and FIQ -dispatchers.

On the template reference board, the registration is -done by TemplateInterrupt::Init1() in ...\template_assp\interrupts.cpp.
void TemplateInterrupt::Init1() - { - // - // need to hook the ARM IRQ and FIQ handlers as early as possible - // and disable and clear all interrupt sources - // - ... - DisableAndClearAll(); - Arm::SetIrqHandler((TLinAddr)TemplateInterrupt::IrqDispatch); - Arm::SetFiqHandler((TLinAddr)TemplateInterrupt::FiqDispatch); - } -
Bind any ISRs that handle -chained or pseudo interrupts

In third phase -initialisation

During third phase initialisation of start-up, the -kernel calls the ASSP's implementation of Asic::Init3().

Note -that interrupts are enabled during third phase initialisation.

Within -your implementation of Init3(), if you need to, call Interrupt::Enable() on -any of the interrupt sources that are bound to a chained or pseudo ISR dispatcher. -You don't need to do this if you are enabling and disabling the main interrupt -on demand as the chained or pseudo-interrupts are enabled and disabled.

+ + + + + +Interrupt +Layer InitialisationThis topic describes how to implement the Asic::Init1() and Asic::Init3() functions +to initialise interrupts. +

In first phase +initialisation

During first phase initialisation of start-up, the +kernel calls the ASSP's implementation of Asic::Init1(). +For the template reference board, where the ASSP is split into a common, ASSP +layer and a device-specific (variant) layer, interrupt handling is initialised +in the ASSP layer, specifically in TemplateAssp::Init1(), +defined in ...\template_assp\template_assp_priv.h, and +implemented in ...\template_assp\assp.cpp.

Note +that interrupts are disabled during first phase initialisation.

Within +your implementation of Init1(), do the following:

Initialise the ISR table.

It is useful to initialise the ISR table so +that each interrupt is bound, by default, to the Spurious interrupts handler, with the 32-bit parameter taking the +interrupt number.

For example,
... +const TInt KInterruptSourceCount = 32; +SInterruptHandler IsrHandlers[KInterruptSourceCount]; +... + +for( TInt i = 0; i < KInterruptSourceCount; ++i ) + { + IsrHandlers[i].iIsr = SpuriousHandler; + IsrHandlers[i].iPtr = (TAny*)i; + }
where the spurious interrupt handler function might be +implemented as:
void SpuriousHandler(TAny* aId) + { + Kern::Fault("SpuriousInt", (TInt)aId); // handle unexpected interrupt. + } +
On the template reference board, the ISR table is initialised +by TemplateInterrupt::Init1() in ...\template_assp\interrupts.cpp, +and this is called by TemplateAssp::Init1().
Register the dispatcher +functions. The Symbian platform kernel needs to know the location of the IRQ +and FIQ dispatchers. It provides the two functions: Arm::SetIrqHandler() and Arm::SetFiqHandler(), +which the Variant layer must call, passing the addresses of the IRQ and FIQ +dispatchers.

On the template reference board, the registration is +done by TemplateInterrupt::Init1() in ...\template_assp\interrupts.cpp.
void TemplateInterrupt::Init1() + { + // + // need to hook the ARM IRQ and FIQ handlers as early as possible + // and disable and clear all interrupt sources + // + ... + DisableAndClearAll(); + Arm::SetIrqHandler((TLinAddr)TemplateInterrupt::IrqDispatch); + Arm::SetFiqHandler((TLinAddr)TemplateInterrupt::FiqDispatch); + } +
Bind any ISRs that handle +chained or pseudo interrupts

In third phase +initialisation

During third phase initialisation of start-up, the +kernel calls the ASSP's implementation of Asic::Init3().

Note +that interrupts are enabled during third phase initialisation.

Within +your implementation of Init3(), if you need to, call Interrupt::Enable() on +any of the interrupt sources that are bound to a chained or pseudo ISR dispatcher. +You don't need to do this if you are enabling and disabling the main interrupt +on demand as the chained or pseudo-interrupts are enabled and disabled.

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