diff options
Diffstat (limited to 'arch/powerpc/cpu/mpc824x/drivers/epic/README')
-rw-r--r-- | arch/powerpc/cpu/mpc824x/drivers/epic/README | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/arch/powerpc/cpu/mpc824x/drivers/epic/README b/arch/powerpc/cpu/mpc824x/drivers/epic/README new file mode 100644 index 00000000000..57989969b90 --- /dev/null +++ b/arch/powerpc/cpu/mpc824x/drivers/epic/README @@ -0,0 +1,102 @@ +CONTENT: + + epic.h + epic1.c + epic2.s + +WHAT ARE THESE FILES: + +These files contain MPC8240 (Kahlua) EPIC +driver routines. The driver routines are not +written for any specific operating system. +They serves the purpose of code sample, and +jump-start for using the MPC8240 EPIC unit. + +For the reason of correctness of C language +syntax, these files are compiled by Metaware +C compiler and assembler. + +ENDIAN NOTATION: + +The algorithm is designed for big-endian mode, +software is responsible for byte swapping. + +USAGE: + +1. The host system that is running on MPC8240 + shall link the files listed here. The memory + location of driver routines shall take into + account of that driver routines need to run + in supervisor mode and they process external + interrupts. + + The routine epic_exception shall be called by + exception vector at location 0x500, i.e., + 603e core external exception vector. + +2. The host system is responsible for configuring + the MPC8240 including Embedded Utilities Memory + Block. All EPIC driver functions require the + content of Embedded Utilities Memory Block + Base Address Register, EUMBBAR, as the first + parameter. + +3. Before EPIC unit of MPC8240 can be used, + initialize EPIC unit by calling epicInit + with the corresponding parameters. + + The initialization shall disable the 603e + core External Exception by calling CoreExtIntDisable( ). + Next, call epicInit( ). Last, enable the 603e core + External Exception by calling CoreExtIntEnable( ). + +4. After EPIC unit has been successfully initialized, + epicIntSourceSet( ) shall be used to register each + external interrupt source. Anytime, an external + interrupt source can be disabled or enabled by + calling corresponding function, epicIntDisable( ), + or epicIntEnable( ). + + Global Timers' resource, base count and frequency, + can be changed by calling epicTmFrequencySet( ) + and epicTmBaseSet( ). + + To stop counting a specific global timer, use + the function, epicTmInhibit while epicTmEnable + can be used to start counting a timer. + +5. To mask a set of external interrupts that are + are certain level below, epicIntPrioritySet( ) + can be used. For example, if the processor's + current task priority register is set to 0x7, + only interrupts of priority 0x8 or higher will + be passed to the processor. + + Be careful when using this function. It may + corrupt the current interrupt pending, selector, + and request registers, resulting an invalid vetor. + + After enabling an interrupt, disable it may also + cause an invalid vector. User may consider using + the spurious vector interrupt service routine to + handle this case. + +6. The EPIC driver routines contains a set + of utilities, Set and Get, for host system + to query and modify the desired EPIC source + registers. + +7. Each external interrupt source shall register + its interrupt service routine. The routine + shall contain all interrupt source specific + processes and keep as short as possible. + + Special customized end of interrupt routine + is optional. If it is needed, it shall contain + the external interrupt source specific end of + interrupt process. + + External interrupt exception vector at 0x500 + shall always call the epicEOI just before + rfi instruction. Refer to the routine, + epic_exception, for a code sample. |