Add basic mesecons/digilines interrupt support

6 files changed, 216 insertions, 0 deletions

diff --git a/assembly/extint-test/Makefile b/assembly/extint-test/Makefile
new file mode 100644
index 0000000..2464c5e
--- /dev/null
+++ b/assembly/extint-test/Makefile
@@ -0,0 +1,24 @@
+MARCH ?= rv32imacbzicntr_zicond_zicsr_zifencei_zihintpause_zilsd_zclsd_zabha_zacas_zbkb_zbkx_zcb_zcmp_zcmt
+
+.PHONY: all dump load clean
+
+all: extint-test.hex
+
+extint-test.o: extint-test.S
+	riscv32-none-elf-as -I../rvcontroller-libraries -march=${MARCH} -o extint-test.o extint-test.S
+
+extint-test.elf:  extint-test.o
+	riscv32-none-elf-ld -T rvcontroller.ld --no-warn-rwx-segments -o extint-test.elf extint-test.o
+
+dump: extint-test.elf
+	riscv32-none-elf-objdump -d extint-test.elf
+
+extint-test.hex: extint-test.elf
+	riscv32-none-elf-objcopy -O ihex extint-test.elf extint-test.hex
+
+load: extint-test.hex
+	bash -c "wl-copy < extint-test.hex"
+
+clean:
+	rm -f extint-test.hex extint-test.elf extint-test.o
+
diff --git a/assembly/extint-test/extint-test.S b/assembly/extint-test/extint-test.S
new file mode 100644
index 0000000..c1b872d
--- /dev/null
+++ b/assembly/extint-test/extint-test.S
@@ -0,0 +1,145 @@
+li t0,0xffff0000
+csrw 0x801,t0 # Map the MMIO region somewhere
+la t0,handler
+csrw mtvec,t0 # Set up trap handler
+li t0,0x400
+csrc mstatush,t0 # Turn off MDT
+li t0,0x30000
+csrw mie,t0 # Mask all interrupts except mesecons/digilines
+csrw mip,zero # Clear any pending interrupts
+csrsi mstatus,0x8 # Turn on MIE to enable interrupts
+
+mainloop:
+li a7,4
+la a0,waitingmsg
+ecall # Print waiting message
+wfi # And do nothing else, this program is entirely interrupt-driven
+j mainloop
+
+
+
+.align 4
+handler:
+csrrw x31,mscratch,x31 # Free up x31 to hold the context address
+la x31,hcontext # Using x register numbers here since trap handlers don't use the usual calling convention
+sw x1,0(x31) # Save all the registers to the context
+sd x2,4(x31) # Two at a time since we have Zilsd/Zclsd
+sd x4,12(x31) # Note that I don't actually _need_ all of the registers in the handler,
+sd x6,20(x31) # but I wanted to try this anyway to see how it goes
+sd x8,28(x31)
+sd x10,36(x31)
+sd x12,44(x31)
+sd x14,52(x31)
+sd x16,60(x31)
+sd x18,68(x31)
+sd x20,76(x31)
+sd x22,84(x31)
+sd x24,92(x31)
+sd x26,100(x31)
+sd x28,108(x31)
+sw x30,116(x31)
+csrr x30,mscratch # Get the old x31 value back into a register
+sw x30,120(x31) # and write that back out too
+
+csrr t0,mcause # Read why the trap occurred
+
+li t1,0x80000010 # Interrupt 16 = mesecons
+beq t0,t1,handler_mesecons
+
+li t1,0x80000011 # Interrupt 17 = digilines
+beq t0,t1,handler_digilines
+
+j handler_other # Something else
+
+handler_mesecons:
+li a7,4
+la a0,meseconsmsg
+ecall # Show that this was a mesecons event
+
+li a7,1
+li t0,0xffff0000
+lb a0,1(t0) # Read the mesecons I/O port value
+ecall # And print that
+
+li a7,11
+li a0,'\n'
+ecall # Line feed
+
+j handler_epilogue
+
+handler_digilines:
+li a7,4
+la a0,digilinesmsg
+ecall # Show that this was a digilines event
+
+li a7,135
+la a0,channelbuf
+li a1,21
+la a2,msgbuf
+li a3,21
+ecall # Read what the event was
+
+li a7,4
+la a0,channelbuf
+ecall # Print the channel
+
+li a7,4
+la a0,digilinesmsg2
+ecall # "Message:", this has its own line feeds in it
+
+li a7,4
+la a0,msgbuf
+ecall # Print the message
+
+li a7,11
+li a0,'\n'
+ecall # Line feed
+
+li a7,134
+ecall # Clear out any other digilines messages
+
+j handler_epilogue
+
+handler_other:
+li a7,4
+la a0,unimplementedmsg
+ecall # Display unimplemented trap message
+
+csrr a0,mcause # Read what the cause was
+li a7,1
+ecall # Tell the user
+
+li a7,10
+ecall # Then halt
+
+handler_epilogue:
+csrw mip,zero # Clear out all pending interrupts
+la x31,hcontext # x numbers here for the same reason as during the save
+lw x1,0(x31) # Load all of the registers from the context
+ld x2,4(x31) # Two at a time since we have Zilsd/Zclsd
+ld x4,12(x31)
+ld x6,20(x31)
+ld x8,28(x31)
+ld x10,36(x31)
+ld x12,44(x31)
+ld x14,52(x31)
+ld x16,60(x31)
+ld x18,68(x31)
+ld x20,76(x31)
+ld x22,84(x31)
+ld x24,92(x31)
+ld x26,100(x31)
+ld x28,108(x31)
+ld x30,116(x31)
+mret # Return to the program (not that the rest of the program does much)
+
+hcontext: .skip 32*4
+
+
+waitingmsg: .asciz "Waiting...\n"
+meseconsmsg: .asciz "Mesecons event!\nInput value: "
+digilinesmsg: .asciz "Digilines event!\nChannel:\n"
+digilinesmsg2: .asciz "\nMessage:\n"
+unimplementedmsg: .asciz "Unimplemented trap!\nmcause: "
+channelbuf: .asciz "                    "
+msgbuf: .asciz "                    "
diff --git a/assembly/extint-test/extint-test.elf b/assembly/extint-test/extint-test.elf
new file mode 100755
index 0000000..15f2f80
--- /dev/null
+++ b/assembly/extint-test/extint-test.elf
diff --git a/assembly/extint-test/extint-test.hex b/assembly/extint-test/extint-test.hex
new file mode 100644
index 0000000..c3382c4
--- /dev/null
+++ b/assembly/extint-test/extint-test.hex
@@ -0,0 +1,46 @@
+:10000000C17273901280970200009382A2037390D2

+:1000100052309302004073B00231B7020300739074

+:10002000423073104034736004309148170500006B

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+:1000500023B22F0023B64F0023BA6F0023BE8F00B8

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+:1000B0001705000013052518730000008548C1725C

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+:10016000CF0483A00F0003B14F0003B2CF0003B34D

+:100170004F0103B4CF0103B54F0203B6CF0203B75B

+:100180004F0303B8CF0303B94F0403BACF0403BB33

+:100190004F0503BCCF0503BD4F0603BECF0603BF0B

+:1001A0004F07730020300000000000000000000036

+:1001B000000000000000000000000000000000003F

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+:1001F00000000000000000000000000000000000FF

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+:1002200000000000000057616974696E672E2E2E71

+:100230000A004D657365636F6E73206576656E7435

+:10024000210A496E7075742076616C75653A2000DC

+:10025000446967696C696E6573206576656E7421A3

+:100260000A4368616E6E656C3A0A000A4D657373E5

+:100270006167653A0A00556E696D706C656D656EF3

+:100280007465642074726170210A6D6361757365B1

+:100290003A20002020202020202020202020202064

+:1002A000202020202020200020202020202020206E

+:1002B00020202020202020202020202000000100BD

+:0402C0001300000027

+:00000001FF

diff --git a/assembly/extint-test/extint-test.o b/assembly/extint-test/extint-test.o
new file mode 100644
index 0000000..3aba761
--- /dev/null
+++ b/assembly/extint-test/extint-test.o
diff --git a/assembly/extint-test/rvcontroller.ld b/assembly/extint-test/rvcontroller.ld
new file mode 120000
index 0000000..bc01402
--- /dev/null
+++ b/assembly/extint-test/rvcontroller.ld
@@ -0,0 +1 @@
+../../rvcontroller.ld
\ No newline at end of file