Git-Mirrors/tillitis-key
1
0
Fork 0
mirror of https://github.com/tillitis/tillitis-key1.git synced 2025-08-07 22:22:29 -04:00
Code Issues Projects Releases Packages Wiki Activity

fpga: Add syscall interrupt

Browse source 
Add syscall interrupt to be used for syscalls. The interrupt is
triggered by writing to an address in the 0xe1000000-0xe1ffffff

The PicoRV32 core is configured to use its minimal, non RISCV-standard,
interrupt implementation.
This commit is contained in:
Mikael Ågren 2024-12-03 17:33:59 +01:00
parent dd48b77047
commit 19ae709c81
No known key found for this signature in database
GPG key ID: E02DA3D397792C46
4 changed files with 118 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

54
hw/application_fpga/rtl/application_fpga.v
View file

@ -57,11 +57,13 @@ module application_fpga (
localparam UART_PREFIX = 6'h03;
localparam TOUCH_SENSE_PREFIX = 6'h04;
localparam FW_RAM_PREFIX = 6'h10;
localparam SYSCALL_PREFIX = 6'h21;
localparam TK1_PREFIX = 6'h3f;
// Instruction used to cause a trap.
localparam ILLEGAL_INSTRUCTION = 32'h0;
localparam IRQ31_IRQ_MASK = 2 ** 31;
//----------------------------------------------------------------
// Registers, memories with associated wires.
@ -80,11 +82,13 @@ module application_fpga (
wire reset_n;
/* verilator lint_off UNOPTFLAT */
reg [31 : 0] cpu_irq;
wire cpu_trap;
wire cpu_valid;
wire cpu_instr;
wire [03 : 0] cpu_wstrb;
/* verilator lint_off UNUSED */
wire [31 : 0] cpu_eoi;
wire [31 : 0] cpu_addr;
wire [31 : 0] cpu_wdata;
@ -139,6 +143,10 @@ module application_fpga (
wire [31 : 0] touch_sense_read_data;
wire touch_sense_ready;
reg irq31_cs;
reg irq31_we;
reg irq31_eoi;
reg tk1_cs;
reg tk1_we;
reg [ 7 : 0] tk1_address;
@ -166,12 +174,17 @@ module application_fpga (
picorv32 #(
.ENABLE_COUNTERS(0),
.TWO_STAGE_SHIFT(0),
.CATCH_MISALIGN (0),
.COMPRESSED_ISA (1),
.ENABLE_FAST_MUL(1),
.BARREL_SHIFTER (1)
.ENABLE_COUNTERS (0),
.TWO_STAGE_SHIFT (0),
.CATCH_MISALIGN (0),
.COMPRESSED_ISA (1),
.ENABLE_FAST_MUL (1),
.BARREL_SHIFTER (1),
.ENABLE_IRQ (1),
.ENABLE_IRQ_QREGS(0),
.ENABLE_IRQ_TIMER(0),
.MASKED_IRQ (~IRQ31_IRQ_MASK),
.LATCHED_IRQ (IRQ31_IRQ_MASK)
) cpu (
.clk(clk),
.resetn(reset_n),
@ -185,11 +198,12 @@ module application_fpga (
.mem_rdata(muxed_rdata_reg),
.mem_instr(cpu_instr),
.irq(cpu_irq),
.eoi(cpu_eoi),
// Defined unused ports. Makes lint happy. But
// we still needs to help lint with empty ports.
/* verilator lint_off PINCONNECTEMPTY */
.irq(32'h0),
.eoi(),
.trace_valid(),
.trace_data(),
.mem_la_read(),
@ -353,6 +367,8 @@ module application_fpga (
.gpio3(app_gpio3),
.gpio4(app_gpio4),
.syscall(irq31_eoi),
.cs(tk1_cs),
.we(tk1_we),
.address(tk1_address),
@ -379,6 +395,20 @@ module application_fpga (
end
//----------------------------------------------------------------
// irq_ctrl
// Interrupt logic
//----------------------------------------------------------------
always @* begin : irq_ctrl
reg irq31_set;
irq31_set = irq31_cs & irq31_we;
cpu_irq = {irq31_set, 31'h0};
irq31_eoi = cpu_eoi[31];
end
//----------------------------------------------------------------
// cpu_mem_ctrl
// CPU memory decode and control logic.
@ -428,6 +458,9 @@ module application_fpga (
touch_sense_we = |cpu_wstrb;
touch_sense_address = cpu_addr[9 : 2];
irq31_cs = 1'h0;
irq31_we = |cpu_wstrb;
tk1_cs = 1'h0;
tk1_we = |cpu_wstrb;
tk1_address = cpu_addr[9 : 2];
@ -500,6 +533,11 @@ module application_fpga (
muxed_ready_new = fw_ram_ready;
end
SYSCALL_PREFIX: begin
irq31_cs = 1'h1;
muxed_ready_new = 1'h1;
end
TK1_PREFIX: begin
tk1_cs = 1'h1;
muxed_rdata_new = tk1_read_data;