internal & external interrupt in Powerpc

pigmeat

在linux/arch/ppc/platforms/85xx/mpc85xx_ads_common.c中可以看到internal 和external 的定义和mpc spec描述基本一致

但是疑惑的是int输入信号只是作为external interrupt，可以理解internal interrupt是为程序执行内部使用的异常。那么为什么internal interrupt 要预留很多给cache, dma, pci, eth等设备接口呢？

**************************
Powerpc Spec
10.1.5.2 Internal Interrupt Sources

Internal Interrupt Number Interrupt Source
Internal Interrupt Number Interrupt Source
0 L2 cache 24 eTSEC2 error
1 ECM 25 Reserved
2 DDR DRAM 26 DUART
3 LBC 27 I2C controllers
4 DMA channel 0 28 Performance monitor
5 DMA channel 1 29 Security channel
6 DMA channel 2 30 Reserved
7 DMA channel 3 31 Unused
8 PCI1 32 Serial RapidIO error/write-port unit
9 PCI2 33 Serial RapidIO outbound doorbell
10 PCI Express 34 Serial RapidIO inbound doorbell
11 Reserved 35 Reserved
12 Reserved 36 Reserved
13 eTSEC1 transmit 37 Serial RapidIO outbound message unit 0

beyond93

internal interrupt是指CPU内部各个控制单元的所产生的中断，external interrupt是CPU外部的器件可以产生中断，这些中断通过相应的管脚传入给CPU。