This makes the ICS support less than the 8 architected bits
and sets the soc to use 3 bits by default.
All the supported bits set translates to "masked" (and will read
back at 0xff), any small value is used as-is.
Linux doesn't use priorities above 5, so this is a way to save
silicon. The number of supported priority bits is exposed to the
OS via the config register.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Move the external interrupt generation to a separate module
"ICS" (source controller) which a register per source containing
currently only the priority control.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
That's how Linux expects it. This also simplifies the
register access implementation since the bit fields now
align properly regardless of the access size.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Use a simple wire. common.vhdl types are better kept for things
local to the core. We can add more wires later if we need to for
HV irqs etc...
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This changes the SoC interconnect such that the main 64-bit wishbone out
of the processor is first split between only 3 slaves (BRAM, DRAM and a
general "IO" bus) instead of all the slaves in the SoC.
The IO bus leg is then latched and down-converted to 32 bits data width,
before going through a second address decoder for the various IO devices.
This significantly reduces routing and timing pressure on the main bus,
allowing to get rid of frequent timing violations when synthetizing on
small'ish FPGAs such as the Artix-7 35T found on the original Arty board.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
New unified ICP and ICS XICS compliant interrupt controller.
Configurable number of hardware sources.
Fixed hardware source number based on hardware line taken. All
hardware interrupts are a fixed priority. Level interrupts supported
only.
Hardwired to 0xc0004000 in SOC (UART is kept at 0xc0002000).
Signed-off-by: Michael Neuling <mikey@neuling.org>
Benjamin Herrenschmidt
Michael Neuling