diff options
| author | Ian Moffett <ian@osmora.org> | 2024-08-03 20:27:20 -0400 |
|---|---|---|
| committer | Ian Moffett <ian@osmora.org> | 2024-08-03 20:55:07 -0400 |
| commit | bf93a581e7daa9802cd27317b0fe2fe455adb280 (patch) | |
| tree | e40aa20d5096b5ba9217b33dfb5c3e3deb3ebf33 /sv/soc/irq | |
| parent | 9bb02c687f45f529c2cb016151db7b1fd1ee35e8 (diff) | |
soc: pimc: Document MMIO interface
Signed-off-by: Ian Moffett <ian@osmora.org>
Diffstat (limited to 'sv/soc/irq')
| -rw-r--r-- | sv/soc/irq/images/irqmask.png | bin | 0 -> 166036 bytes | |||
| -rw-r--r-- | sv/soc/irq/irqchip.md | 37 |
2 files changed, 37 insertions, 0 deletions
diff --git a/sv/soc/irq/images/irqmask.png b/sv/soc/irq/images/irqmask.png Binary files differnew file mode 100644 index 0000000..2feddb2 --- /dev/null +++ b/sv/soc/irq/images/irqmask.png diff --git a/sv/soc/irq/irqchip.md b/sv/soc/irq/irqchip.md index e4705a7..d011e15 100644 --- a/sv/soc/irq/irqchip.md +++ b/sv/soc/irq/irqchip.md @@ -11,6 +11,11 @@ each connected to their respective IRQ lines. | IRQACK | Interrupt acknowledgement | | LINENO[7:0] | IRQ line to be serviced | | NOTIFY# | Signals an active IRQ | +| MMIO_ADDR | MMIO r/w address | +| MMIO_RE | MMIO read enable | +| MMIO_WE | MMIO write enable | +| MMIO_WDATA | MMIO write data | +| MMIO_RDATA | MMIO read data | | CLK | PIMC Clock | ## PIMC Startup State @@ -38,3 +43,35 @@ it can be acknowledged by pulsing IRQACK high for 2 ms. After an IRQ has been ac is pulled high and LINENO[7:0] is cleared to zero.  + +## MMIO Interface + +Some registers within the PIMC chip are memory mapped and can be accessed through the MMIO interface. For example, +the IRQ table is accessed through physical address 0x1000 + OFFSET. + +### MMIO Interface Semantics + +The MMIO_ADDR input from mainbus is set to the address being accessed. The MMIO_RE (Read Enable) and +MMIO_WE (Write Enable) signals are used for read/write operations and are mutually exclusive. As soon as one +of these signals are pulled high, data transfer begins. + +- Pulse MMIO_RE high to read data onto MMIO_RDATA. +- Pulse MMIO_WE high to write data from MMIO_WDATA. + + + +### MMIO Interface Registers + +#### IRQ Table + +The IRQ table is a set of registers that manage where and how IRQs get directed. +The IRQ line number acts as the index into this table. + +| Bits | Field | +| ----------- | ------------- | +| 7:0 | Processor ID | +| 8 | Line mask | +| 31:9 | Reserved | + +The Processor ID field contains the ID of the processor for this IRQ to be directed to. +If the Line Mask bit is set to 1, the PIMC chip will ignore interrupts from this line. |
