io_mem_dma.v
37.7 KB
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/************************************************************************\
* *
* Copyright (C) 1994, Silicon Graphics, Inc. *
* *
* These coded instructions, statements, and computer programs contain *
* unpublished proprietary information of Silicon Graphics, Inc., and *
* are protected by Federal copyright law. They may not be disclosed *
* to third parties or copied or duplicated in any form, in whole or *
* in part, without the prior written consent of Silicon Graphics, Inc. *
* *
\************************************************************************/
// $Id: io_mem_dma.v,v 1.1.1.1 2002/05/17 06:14:57 blythe Exp $
module io_mem_dma(clock, reset_l,
cp0_enable, cbus_read_enable, cbus_write_enable, cbus_select, cbus_command,
dma_start, dma_last, dma_grant, read_grant, cp0_cmd_select, cp0_address,
cp0_read, cp0_write, set_broke, cmd_read, cmd_address, bist_done, bist_fail,
dma_request, reg_read_request, mem_read_request, imem_select, mem_address,
mem_read, mem_write, mem_mask, halt, single_step, dma_busy, cmd_ready,
pc_write, pc_data, io_read_select, io_write_select, mem_load, io_load,
interrupt, bist_go, bist_check,
cp0_data, cbus_data);
`include "sp.vh"
input clock; // system clock
input reset_l; // system reset_l
input cp0_enable; // enable cp0 tristate drivers
input cbus_read_enable; // enable cbus read mux
input cbus_write_enable; // enable cbus tristate drivers
input [CBUS_SELECT_SIZE-1:0] cbus_select; // cbus data select
input [CBUS_COMMAND_SIZE-1:0] cbus_command; // cbus data type
input dma_start; // dbus DMA data start
input dma_last; // dbus DMA data end
input dma_grant; // SP DMA request granted
input read_grant; // SP read request granted
input cp0_cmd_select; // sp selected
input [SP_REG_ADDRESS_SIZE-1:0] cp0_address; // DMA register address
input cp0_read; // enable register read
input cp0_write; // enable register write
input set_broke; // status from RSP
input cmd_read; // DP DMEM read request
input [SP_MEM_ADDRESS_SIZE-1:0] cmd_address; // DP DMEM read address
input bist_done; // IMEM BIST done (pulse)
input [SP_BIST_FAIL_SIZE-1:0] bist_fail; // IMEM BIST fail (pulse)
output dma_request; // sp DMA request
output reg_read_request; // reg read request
output mem_read_request; // dmem/imem read request
output imem_select; // enable IMEM read/write
output [SP_MEM_ADDRESS_SIZE-1:0] mem_address; // DMEM/IMEM address
output mem_read; // read DMA in progress
output mem_write; // write DMA in progress
output [SP_MEM_MASK_SIZE-1:0] mem_mask; // DMA read/write byte mask
output halt; // status to RSP
output single_step; // status to RSP
output dma_busy; // status to RSP
output cmd_ready; // DP CMDBUF read ready
output pc_write; // program counter write enable
output [SP_PC_SIZE-1:0] pc_data; // program counter write data bus
output io_read_select; // select high/low data
output io_write_select; // select IO write data
output mem_load; // load cbus reg from imem/dmem
output io_load; // load cbus reg from cbus
output interrupt; // rsp generated interrupt
output bist_go; // start IMEM BIST
output bist_check; // BIST BIST
inout [CP0_DATA_SIZE-1:0] cp0_data; // CP0 data bus
inout [CBUS_DATA_SIZE-1:0] cbus_data; // IO data bus
mem_dma mem_dma(clock, reset_l,
cp0_enable, cbus_read_enable, cbus_write_enable, cbus_select, cbus_command,
dma_start, dma_last, dma_grant, read_grant, cp0_cmd_select, cp0_address,
cp0_read, cp0_write, set_broke, cmd_read, cmd_address, bist_done, bist_fail,
dma_request, reg_read_request, mem_read_request, imem_select, mem_address,
mem_read, mem_write, mem_mask, halt, single_step, dma_busy, cmd_ready,
pc_write, pc_data, io_read_select, io_write_select, mem_load, io_load,
interrupt, bist_go, bist_check,
cp0_data, cp0_data, cbus_data, cbus_data);
endmodule
module mem_dma(clock, reset_l,
cp0_enable, cbus_read_enable, cbus_write_enable, cbus_select, cbus_command,
dma_start, dma_last, dma_grant, read_grant, cp0_cmd_select, cp0_address,
cp0_read, cp0_write, set_broke, cmd_read, cmd_address, bist_done, bist_fail,
dma_request, reg_read_request, mem_read_request, imem_select, mem_address,
mem_read, mem_write, mem_mask, halt, single_step, dma_busy, cmd_ready,
pc_write, pc_data, io_read_select, io_write_select, mem_load, io_load,
interrupt, bist_go, bist_check, cp0_data_in, cp0_data, cbus_data_in, cbus_data);
`include "sp.vh"
input clock; // system clock
input reset_l; // system reset_l
input cp0_enable; // enable cp0 tristate drivers
input cbus_read_enable; // enable cbus read mux
input cbus_write_enable; // enable cbus tristate drivers
input [CBUS_SELECT_SIZE-1:0] cbus_select; // cbus data select
input [CBUS_COMMAND_SIZE-1:0] cbus_command; // cbus data type
input dma_start; // dbus DMA data start
input dma_last; // dbus DMA data end
input dma_grant; // SP DMA request granted
input read_grant; // SP read request granted
input cp0_cmd_select; // sp selected
input [SP_REG_ADDRESS_SIZE-1:0] cp0_address; // DMA register address
input cp0_read; // enable register read
input cp0_write; // enable register write
input set_broke; // status from RSP
input cmd_read; // DP DMEM read request
input [SP_MEM_ADDRESS_SIZE-1:0] cmd_address; // DP DMEM read address
input bist_done; // IMEM BIST done (pulse)
input [SP_BIST_FAIL_SIZE-1:0] bist_fail; // IMEM BIST fail (pulse)
output dma_request; // sp DMA request
output reg_read_request; // reg read request
output mem_read_request; // dmem/imem read request
output imem_select; // enable IMEM read/write
output [SP_MEM_ADDRESS_SIZE-1:0] mem_address; // DMEM/IMEM address
output mem_read; // read DMA in progress
output mem_write; // write DMA in progress
output [SP_MEM_MASK_SIZE-1:0] mem_mask; // DMA read/write byte mask
output halt; // status to RSP
output single_step; // status to RSP
output dma_busy; // status to RSP
output cmd_ready; // DP CMDBUF read ready
output pc_write; // program counter write enable
output [SP_PC_SIZE-1:0] pc_data; // program counter write data bus
output io_read_select; // select high/low data
output io_write_select; // select IO write data
output mem_load; // load cbus reg from imem/dmem
output io_load; // load cbus reg from cbus
output interrupt; // rsp generated interrupt
output bist_go; // start IMEM BIST
output bist_check; // BIST BIST
input [CP0_DATA_SIZE-1:0] cp0_data_in; // CP0 data bus
output [CP0_DATA_SIZE-1:0] cp0_data; // CP0 data bus
input [CBUS_DATA_SIZE-1:0] cbus_data_in; // IO data bus
output [CBUS_DATA_SIZE-1:0] cbus_data; // IO data bus
// input/output registers
reg dma_request;
reg reg_read_request;
reg mem_read_request;
reg imem_select;
reg [SP_DMA_MASTER_ADDRESS_SIZE-1:0] mem_address;
reg mem_read;
reg mem_write;
reg [SP_MEM_MASK_SIZE-1:0] mem_mask;
reg halt;
reg single_step;
reg dma_busy;
reg pc_write;
reg io_read_select;
reg io_write_select;
reg mem_load;
reg interrupt;
reg [CBUS_COMMAND_SIZE-1:0] cbus_command_reg;
reg [CBUS_DATA_SIZE-1:0] cbus_data_reg;
// output pseudo registers
reg [CP0_DATA_SIZE-1:0] cp0_data_out;
// SP access registers
reg master_imem_select;
reg [SP_DMA_MASTER_ADDRESS_SIZE-1:0] master_address;
reg [SP_DMA_SLAVE_ADDRESS_SIZE-1:0] slave_address;
reg [SP_DMA_SKIP_SIZE-1:0] skip;
reg [SP_DMA_COUNT_SIZE-1:0] count;
reg [SP_DMA_LENGTH_SIZE-1:0] length;
reg read;
reg [SP_MEM_ADDRESS_SIZE+1:0] io_read_address;
reg [SP_MEM_ADDRESS_SIZE+1:0] io_write_address;
reg reg_select;
reg dma_full;
reg io_read_full;
reg io_write_full;
reg broke;
reg interrupt_on_break;
// request registers
reg [SP_DMA_MASTER_ADDRESS_SIZE-1:0] master_address_sum;
reg [SP_DMA_SLAVE_ADDRESS_SIZE-1:0] slave_address_sum;
reg [SP_DMA_LENGTH_SIZE-1:0] length_sum;
reg [SP_DMA_COUNT_SIZE-1:0] count_sum;
reg [SP_DMA_SKIP_SIZE-1:0] skip_pl;
reg [SP_DMA_LENGTH_SIZE-1:0] length_pl;
reg read_pl;
reg [DMA_LENGTH_SIZE-1:0] transfer_length;
reg imem_select_pl;
reg dma_imem_select_pl;
reg [SP_DMA_MASTER_ADDRESS_SIZE-1:0] dma_mem_address_pl;
reg dma_read_pl;
reg dma_valid;
reg io_valid;
reg cpu_semaphore_read;
reg cpu_semaphore_write;
reg cpu_semaphore;
reg semaphore;
// dma registers
reg [SP_DMA_MASTER_ADDRESS_SIZE-1:0] mem_address_sum;
reg mem_busy;
// bist and signal registers
reg bist_go;
reg bist_check;
reg bist_done_reg;
reg [SP_BIST_FAIL_SIZE-1:0] bist_fail_reg;
reg [SP_SIGNAL_SIZE-1:0] signal;
// bus state machine
reg [1:0] bus_state;
parameter
STATE_BUS_IDLE = 0,
STATE_BUS_REG_WRITE = 1,
STATE_BUS_REG_READ = 2,
STATE_BUS_MEM_READ = 3;
// request state machine
reg [1:0] request_state;
parameter
STATE_REQUEST_IDLE = 0,
STATE_REQUEST_IO = 1,
STATE_REQUEST_DMA = 2,
STATE_REQUEST_NEXT = 3;
// DMA state machine
reg [2:0] dma_state;
parameter
STATE_DMA_IDLE = 0,
STATE_WRITE_PRIMARY = 1,
STATE_WRITE_SECONDARY = 2,
STATE_READ_PRIMARY = 3,
STATE_READ_SECONDARY = 4;
// CMD state machine
reg cmd_state;
parameter
STATE_CMD_PRIMARY = 0,
STATE_CMD_SECONDARY = 1;
// IO state machine
reg[2:0] io_state;
parameter
STATE_IO_IDLE = 0,
STATE_IO_READ_1 = 1,
STATE_IO_READ_2 = 2,
STATE_IO_READ_3 = 3,
STATE_IO_IMEM_WRITE_1 = 4,
STATE_IO_IMEM_WRITE_2 = 5,
STATE_IO_IMEM_WRITE_3 = 6,
STATE_IO_WRITE = 7;
// cbus tristate drivers
wire mem_cp0_enable = cp0_enable & ~cp0_cmd_select;
cp0_driver cp0_driver_0(cp0_data_out, mem_cp0_enable, cp0_data);
cbus_driver cbus_driver_0(cbus_data_reg, cbus_write_enable, cbus_data);
// Program counter write data
assign pc_data = cbus_data_reg >> SP_PC_OFFSET;
// DP CMDBUF DMA ready logic
assign cmd_ready = ~io_valid & ~mem_busy;
// IO select logic
wire [SP_MEM_ADDRESS_SIZE+1:0] next_io_address;
wire [BUS_ID_SIZE-1:0] next_id_select;
wire [SP_DEVICE_SIZE-1:0] next_device_select;
wire next_sp_select;
wire next_mem_select;
wire next_cp0_select;
wire next_reg_select;
wire next_write_command;
wire next_read_command;
assign next_io_address = cbus_data_reg >> IO_OFFSET_SIZE;
assign next_id_select = cbus_data_reg >> BUS_ID_OFFSET;
assign next_device_select = cbus_data_reg >> SP_DEVICE_OFFSET;
assign next_sp_select = next_id_select == BUS_ID_SP;
assign next_mem_select = next_device_select == SP_DEVICE_MEM;
assign next_cp0_select = next_device_select == SP_DEVICE_CP0;
assign next_reg_select = next_device_select == SP_DEVICE_REG;
assign next_write_command
= (cbus_command_reg == CBUS_WRITE_COMMAND) && next_sp_select;
assign next_read_command
= (cbus_command_reg == CBUS_READ_COMMAND) && next_sp_select;
assign io_load = next_write_command && next_mem_select;
wire [CBUS_DATA_SIZE-1:0] read_status;
assign read_status = {signal, interrupt_on_break, single_step,
io_write_full, dma_full, dma_busy, broke, halt};
// DMA register read
always @(cp0_address or imem_select_pl or master_address_sum
or slave_address_sum or skip_pl or count_sum or length_sum
or read_status or dma_full or dma_busy or semaphore or cpu_semaphore_write)
case (cp0_address)
SP_DMA_MASTER_ADDRESS :
cp0_data_out = {imem_select_pl, master_address_sum, 3'b0};
SP_DMA_SLAVE_ADDRESS :
cp0_data_out = {slave_address_sum, 3'b0};
SP_DMA_READ_LENGTH, SP_DMA_WRITE_LENGTH :
cp0_data_out = {skip_pl, 3'b0, count_sum, length_sum, 3'b0};
SP_DMA_STATUS :
cp0_data_out = read_status;
SP_DMA_FULL :
cp0_data_out = dma_full;
SP_DMA_BUSY :
cp0_data_out = dma_busy;
SP_DMA_SEMAPHORE :
cp0_data_out = semaphore && !cpu_semaphore_write;
default :
cp0_data_out = 'bx;
endcase
always @(posedge clock) begin : cbus_block
reg [DMA_ADDRESS_SIZE-1:0] address;
reg [DMA_LENGTH_SIZE-1:0] length;
reg [DMA_DELAY_SIZE-1:0] delay;
reg [CBUS_DATA_SIZE-1:0] cbus_data_out;
address = {slave_address_sum, 3'b000};
length = {transfer_length, 3'b111};
delay = read_pl ? 2 : -5;
case (cbus_select)
CBUS_ADDRESS_SELECT :
cbus_data_out = address;
CBUS_LENGTH_SELECT :
cbus_data_out = {BUS_DEVICE_SP, delay, read_pl, length};
CBUS_DATA_SELECT :
if (reg_select) case (io_read_address[SP_REG_ADDRESS_SIZE-1:0])
SP_REG_PC :
cbus_data_out = cp0_data_in[SP_PC_SIZE-1:0] << SP_PC_OFFSET;
SP_REG_BIST :
cbus_data_out
= {bist_fail_reg, bist_done_reg, bist_go, bist_check};
default :
cbus_data_out = 'bx;
endcase
else case (io_read_address[SP_REG_ADDRESS_SIZE-1:0])
SP_DMA_MASTER_ADDRESS :
cbus_data_out = {imem_select_pl, master_address_sum, 3'b0};
SP_DMA_SLAVE_ADDRESS :
cbus_data_out = {slave_address_sum, 3'b0};
SP_DMA_READ_LENGTH, SP_DMA_WRITE_LENGTH :
cbus_data_out = {skip_pl, 3'b0, count_sum, length_sum, 3'b0};
SP_DMA_STATUS :
cbus_data_out = read_status;
SP_DMA_FULL :
cbus_data_out = dma_full;
SP_DMA_BUSY :
cbus_data_out = dma_busy;
SP_DMA_SEMAPHORE :
cbus_data_out = cpu_semaphore;
default :
cbus_data_out = 'bx;
endcase
default :
cbus_data_out = 'bx;
endcase
cbus_command_reg <= cbus_command;
cbus_data_reg <= cbus_read_enable ? cbus_data_in : cbus_data_out;
end
always @(posedge clock or negedge reset_l) begin
if (!reset_l) begin
// resetable registers
dma_request <= LOW;
reg_read_request <= LOW;
mem_read_request <= LOW;
mem_read <= LOW;
mem_write <= LOW;
mem_mask <= 0;
halt <= HIGH;
single_step <= LOW;
dma_busy <= LOW;
pc_write <= LOW;
mem_load <= LOW;
interrupt <= LOW;
dma_full <= LOW;
io_read_full <= LOW;
io_write_full <= LOW;
broke <= LOW;
interrupt_on_break <= LOW;
dma_valid <= LOW;
io_valid <= LOW;
mem_busy <= LOW;
bist_go <= LOW;
bist_check <= LOW;
master_imem_select <= 0;
master_address <= 0;
slave_address <= 0;
skip <= 0;
count <= 0;
length <= 0;
read <= LOW;
signal <= 0;
bus_state <= STATE_BUS_IDLE;
request_state <= STATE_REQUEST_IDLE;
dma_state <= STATE_DMA_IDLE;
cmd_state <= STATE_CMD_PRIMARY;
io_state <= STATE_IO_IDLE;
imem_select <= 0;
mem_address <= 0;
io_read_select <= LOW;
io_write_select <= LOW;
io_read_address <= 0;
io_write_address <= 0;
reg_select <= LOW;
master_address_sum <= 0;
slave_address_sum <= 0;
length_sum <= 0;
count_sum <= 0;
skip_pl <= 0;
length_pl <= 0;
read_pl <= LOW;
transfer_length <= 0;
imem_select_pl <= 0;
dma_imem_select_pl <= 0;
dma_mem_address_pl <= 0;
dma_read_pl <= LOW;
mem_address_sum <= 0;
bist_done_reg <= LOW;
bist_fail_reg <= 0;
cpu_semaphore_read <= LOW;
cpu_semaphore_write <= LOW;
cpu_semaphore <= LOW;
semaphore <= LOW;
end
else begin : main_block
reg [SP_REG_ADDRESS_SIZE-1:0] reg_address;
reg [SP_REG_DATA_SIZE-1:0] reg_data;
reg dma_reg_write;
reg io_status_reg_write;
reg cp0_status_reg_write;
reg [SP_MEM_MASK_SIZE-1:0] next_mem_mask;
reg next_pc_write;
reg next_mem_write;
reg next_mem_read;
reg set_interrupt;
reg clear_interrupt;
reg set_single_step;
reg clear_single_step;
reg clear_broke;
reg set_halt;
reg clear_halt;
reg set_interrupt_on_break;
reg clear_interrupt_on_break;
reg [SP_SIGNAL_SIZE-1:0] set_signal;
reg [SP_SIGNAL_SIZE-1:0] clear_signal;
reg next_reg_read_request;
reg next_mem_read_request;
reg next_mem_load;
reg next_mem_busy;
reg next_cpu_semaphore_read;
reg next_cpu_semaphore_write;
reg load_io_mem_address;
reg load_dma_mem_address;
reg load_count;
reg decrement_count;
reg [7:0] max_page;
reg [SP_DMA_SLAVE_ADDRESS_SIZE-1:0] slave_address_adder0;
reg [SP_DMA_SLAVE_ADDRESS_SIZE-1:0] slave_address_adder1;
reg slave_address_adder2;
reg [SP_DMA_MASTER_ADDRESS_SIZE-1:0] master_address_adder0;
reg [SP_DMA_MASTER_ADDRESS_SIZE-1:0] master_address_adder1;
reg [SP_DMA_LENGTH_SIZE-1:0] length_adder0;
reg [SP_DMA_LENGTH_SIZE-1:0] length_adder1;
reg next_dma_full;
reg next_dma_busy;
reg next_io_imem_select;
reg [SP_MEM_ADDRESS_SIZE-1:0] next_io_mem_address;
reg next_io_word_select;
reg next_bist_done;
reg [SP_BIST_FAIL_SIZE-1:0] next_bist_fail;
reg cp0_semaphore_select;
reg cp0_semaphore_read;
reg cp0_semaphore_write;
next_mem_mask = 0;
next_pc_write = LOW;
next_mem_write = LOW;
next_mem_read = LOW;
next_reg_read_request = LOW;
next_mem_read_request = LOW;
next_mem_load = LOW;
next_mem_busy = LOW;
next_dma_full = dma_full;
next_dma_busy = LOW;
next_cpu_semaphore_read = LOW;
next_cpu_semaphore_write = LOW;
load_io_mem_address = LOW;
load_dma_mem_address = LOW;
load_count = LOW;
decrement_count = LOW;
set_interrupt = LOW;
clear_interrupt = LOW;
set_single_step = LOW;
clear_single_step = LOW;
clear_broke = LOW;
set_halt = LOW;
clear_halt = LOW;
set_interrupt_on_break = LOW;
clear_interrupt_on_break = LOW;
set_signal = 0;
clear_signal = 0;
slave_address_adder0 = slave_address_sum;
slave_address_adder1 = 0;
slave_address_adder2 = LOW;
master_address_adder0 = master_address_sum;
master_address_adder1 = -1;
length_adder0 = length_sum;
length_adder1 = -1;
{next_io_imem_select, next_io_mem_address, next_io_word_select} =
io_write_full ? io_write_address : io_read_address;
reg_address = cp0_address;
reg_data = cp0_data_in;
dma_reg_write = LOW;
io_status_reg_write = LOW;
cp0_status_reg_write = LOW;
// bist pulse capture
next_bist_done = bist_done_reg | bist_done;
next_bist_fail = bist_fail_reg | bist_fail;
// semaphore control
cp0_semaphore_select = cp0_address == SP_DMA_SEMAPHORE;
cp0_semaphore_read = cp0_read && cp0_semaphore_select;
cp0_semaphore_write = cp0_write && cp0_semaphore_select;
if (cp0_write && !cp0_cmd_select) begin
if (cp0_address[SP_REG_ADDRESS_SIZE-1:0] == SP_DMA_STATUS) begin
cp0_status_reg_write = HIGH;
end
else begin
dma_reg_write = HIGH;
end
end
// CBUS read/write
case (bus_state)
STATE_BUS_IDLE : begin
if (next_write_command) begin
// IO write
io_write_address <= next_io_address;
reg_select <= next_reg_select;
case (HIGH) // synopsys parallel_case
next_mem_select : begin
if (io_write_full) begin
$display("Panic! MEM write register overflow");
$finish;
end
else begin
io_write_full <= HIGH;
end
bus_state <= STATE_BUS_IDLE;
end
next_cp0_select : begin
bus_state <= STATE_BUS_REG_WRITE;
end
next_reg_select : begin
next_pc_write =
next_io_address[SP_REG_ADDRESS_SIZE-1:0] == SP_REG_PC;
bus_state <= STATE_BUS_REG_WRITE;
end
default : begin
bus_state <= STATE_BUS_IDLE;
end
endcase
end
else if (next_read_command) begin
// IO read
io_read_address <= next_io_address;
reg_select <= next_reg_select;
case (HIGH) // synopsys parallel_case
next_mem_select : begin
if (io_read_full) begin
$display("Panic! MEM read register overflow");
$finish;
end
else begin
io_read_full <= HIGH;
end
bus_state <= STATE_BUS_MEM_READ;
end
next_cp0_select : begin
next_cpu_semaphore_read =
next_io_address[SP_REG_ADDRESS_SIZE-1:0]
== SP_DMA_SEMAPHORE;
next_reg_read_request = HIGH;
bus_state <= STATE_BUS_REG_READ;
end
next_reg_select : begin
next_reg_read_request = HIGH;
bus_state <= STATE_BUS_REG_READ;
end
default : begin
bus_state <= STATE_BUS_IDLE;
end
endcase
end
else begin
bus_state <= STATE_BUS_IDLE;
end
end
STATE_BUS_REG_WRITE : begin
if (reg_select) begin
if (io_write_address[SP_REG_ADDRESS_SIZE-1:0] == SP_REG_BIST)
begin : bist_block
reg next_bist_go;
reg next_bist_check;
reg clear_bist;
{clear_bist, next_bist_go, next_bist_check} = cbus_data_reg;
bist_go <= next_bist_go;
bist_check <= next_bist_check;
if (clear_bist) begin
next_bist_done = LOW;
next_bist_fail = 0;
end
end
end
else begin
case (io_write_address[SP_REG_ADDRESS_SIZE-1:0])
SP_DMA_STATUS : begin
io_status_reg_write = HIGH;
end
SP_DMA_SEMAPHORE : begin
next_cpu_semaphore_write = HIGH;
end
SP_DMA_MASTER_ADDRESS, SP_DMA_SLAVE_ADDRESS,
SP_DMA_READ_LENGTH, SP_DMA_WRITE_LENGTH : begin
reg_address = io_write_address;
reg_data = cbus_data_reg;
dma_reg_write = HIGH;
end
endcase
end
bus_state <= STATE_BUS_IDLE;
end
STATE_BUS_REG_READ : begin
if (read_grant) begin
bus_state <= STATE_BUS_IDLE;
end
else begin
next_reg_read_request = HIGH;
bus_state <= STATE_BUS_REG_READ;
end
end
STATE_BUS_MEM_READ : begin
if (io_read_full) begin
// wait for read data
bus_state <= STATE_BUS_MEM_READ;
end
else if (read_grant) begin
// read is complete
bus_state <= STATE_BUS_IDLE;
end
else begin
// begin or continue IO read request
next_mem_read_request = HIGH;
bus_state <= STATE_BUS_MEM_READ;
end
end
default : begin
bus_state <= 'bx;
end
endcase
if (dma_reg_write) begin
// write to a DMA register
case (reg_address)
SP_DMA_MASTER_ADDRESS : begin
if (dma_full) begin
// set error bit
$display("Panic! DMA register double buffer overflow");
$finish;
end
else begin
// write the SP master address register
{master_imem_select, master_address}
<= reg_data >> DMA_OFFSET_SIZE;
end
end
SP_DMA_SLAVE_ADDRESS : begin
if (dma_full) begin
// set error bit
$display("Panic! DMA register double buffer overflow");
$finish;
end
else begin
// write the RDRAM slave address register
slave_address <= reg_data >> DMA_OFFSET_SIZE;
end
end
SP_DMA_READ_LENGTH : begin
if (dma_full) begin
// set error bit
$display("Panic! DMA register double buffer overflow");
$finish;
end
else begin
// write skip, length, and count register
// and begin a DMA read
next_dma_full = HIGH;
length <= reg_data >> DMA_OFFSET_SIZE;
count <= reg_data
>> (DMA_OFFSET_SIZE + SP_DMA_LENGTH_SIZE);
skip <= reg_data
>> (DMA_OFFSET_SIZE*2 + SP_DMA_LENGTH_SIZE
+ SP_DMA_COUNT_SIZE);
read <= HIGH;
end
end
SP_DMA_WRITE_LENGTH : begin
if (dma_full) begin
// set error bit
$display("Panic! DMA register double buffer overflow");
$finish;
end
else begin
// write skip, length, and count register
// and begin a DMA write
next_dma_full = HIGH;
length <= reg_data >> DMA_OFFSET_SIZE;
count <= reg_data
>> (DMA_OFFSET_SIZE + SP_DMA_LENGTH_SIZE);
skip <= reg_data
>> (DMA_OFFSET_SIZE*2 + SP_DMA_LENGTH_SIZE
+ SP_DMA_COUNT_SIZE);
read <= LOW;
end
end
endcase
end
if (io_status_reg_write) begin : io_status_block
reg next_set_interrupt_on_break, next_clear_interrupt_on_break;
reg [SP_SIGNAL_SIZE-1:0] next_set_signal, next_clear_signal;
reg next_set_single_step, next_clear_single_step;
reg next_set_interrupt, next_clear_interrupt;
reg next_clear_broke;
reg next_set_halt, next_clear_halt;
{
next_set_signal[7], next_clear_signal[7],
next_set_signal[6], next_clear_signal[6],
next_set_signal[5], next_clear_signal[5],
next_set_signal[4], next_clear_signal[4],
next_set_signal[3], next_clear_signal[3],
next_set_signal[2], next_clear_signal[2],
next_set_signal[1], next_clear_signal[1],
next_set_signal[0], next_clear_signal[0],
next_set_interrupt_on_break, next_clear_interrupt_on_break,
next_set_single_step, next_clear_single_step,
next_set_interrupt, next_clear_interrupt,
next_clear_broke,
next_set_halt, next_clear_halt
} = cbus_data_reg;
set_interrupt_on_break
= next_set_interrupt_on_break | set_interrupt_on_break;
clear_interrupt_on_break
= next_clear_interrupt_on_break | clear_interrupt_on_break;
set_signal = next_set_signal | set_signal;
clear_signal = next_clear_signal | clear_signal;
set_single_step = next_set_single_step | set_single_step;
clear_single_step = next_clear_single_step | clear_single_step;
set_interrupt = next_set_interrupt | set_interrupt;
clear_interrupt = next_clear_interrupt | clear_interrupt;
clear_broke = next_clear_broke | clear_broke;
set_halt = next_set_halt | set_halt;
clear_halt = next_clear_halt | clear_halt;
end
if (cp0_status_reg_write) begin : cp0_status_block
reg next_set_interrupt_on_break, next_clear_interrupt_on_break;
reg [SP_SIGNAL_SIZE-1:0] next_set_signal, next_clear_signal;
reg next_set_single_step, next_clear_single_step;
reg next_set_interrupt, next_clear_interrupt;
reg next_clear_broke;
reg next_set_halt, next_clear_halt;
{
next_set_signal[7], next_clear_signal[7],
next_set_signal[6], next_clear_signal[6],
next_set_signal[5], next_clear_signal[5],
next_set_signal[4], next_clear_signal[4],
next_set_signal[3], next_clear_signal[3],
next_set_signal[2], next_clear_signal[2],
next_set_signal[1], next_clear_signal[1],
next_set_signal[0], next_clear_signal[0],
next_set_interrupt_on_break, next_clear_interrupt_on_break,
next_set_single_step, next_clear_single_step,
next_set_interrupt, next_clear_interrupt,
next_clear_broke,
next_set_halt, next_clear_halt
} = cp0_data_in;
set_interrupt_on_break
= next_set_interrupt_on_break | set_interrupt_on_break;
clear_interrupt_on_break
= next_clear_interrupt_on_break | clear_interrupt_on_break;
set_signal = next_set_signal | set_signal;
clear_signal = next_clear_signal | clear_signal;
set_single_step = next_set_single_step | set_single_step;
clear_single_step = next_clear_single_step | clear_single_step;
set_interrupt = next_set_interrupt | set_interrupt;
clear_interrupt = next_clear_interrupt | clear_interrupt;
clear_broke = next_clear_broke | clear_broke;
set_halt = next_set_halt | set_halt;
clear_halt = next_clear_halt | clear_halt;
end
// caluculate the length of the DMA, assuming a 2K byte page boundary
// and a 16 cycle block boundary
// Note: transfer_length = # bytes to transfer - 1
// max_page = # bytes left on RDRAM page - 1
// SP_DMA_MAX_BLOCK = max number of DMA clocks - 1
max_page = ~slave_address_sum;
if (length_sum > SP_DMA_MAX_BLOCK) begin
if (SP_DMA_MAX_BLOCK > max_page) begin
transfer_length <= max_page;
end
else begin
transfer_length <= SP_DMA_MAX_BLOCK;
end
end
else begin
if (length_sum > max_page) begin
transfer_length <= max_page;
end
else begin
transfer_length <= length_sum;
end
end
// DMA request state machine
case (request_state)
STATE_REQUEST_IDLE : begin
if (io_read_full || io_write_full) begin
io_valid <= HIGH;
request_state <= STATE_REQUEST_IO;
end
else if (dma_full) begin
slave_address_adder0 = slave_address;
slave_address_adder1 = 0;
slave_address_adder2 = LOW;
master_address_adder0 = master_address;
master_address_adder1 = -1;
length_adder0 = length;
length_adder1 = -1;
load_count = HIGH;
next_dma_full = LOW;
next_dma_busy = HIGH;
skip_pl <= skip;
length_pl <= length;
read_pl <= read;
imem_select_pl <= master_imem_select;
dma_request <= HIGH;
request_state <= STATE_REQUEST_DMA;
end
else begin
request_state <= STATE_REQUEST_IDLE;
end
end
STATE_REQUEST_IO : begin
// wait for IO to complete
if (io_valid) begin
request_state <= STATE_REQUEST_IO;
end
else begin
request_state <= STATE_REQUEST_IDLE;
end
end
STATE_REQUEST_DMA : begin
// request the cbus if the slave device is ready
// Note: we will be in this state for at lease two cycles, so
// transfer_length will be valid before it is needed
next_dma_busy = HIGH;
// wait for the cbus to be granted
if (dma_grant) begin
// calculate the start of the next DMA
slave_address_adder0 = slave_address_sum;
slave_address_adder1 = transfer_length;
slave_address_adder2 = HIGH;
master_address_adder0 = master_address_sum;
master_address_adder1 = transfer_length;
length_adder0 = length_sum;
length_adder1 = transfer_length;
next_mem_busy = HIGH;
dma_imem_select_pl <= imem_select_pl;
dma_mem_address_pl <= master_address_sum;
dma_read_pl <= read_pl;
dma_valid <= HIGH;
dma_request <= LOW;
request_state <= STATE_REQUEST_NEXT;
end
else begin
dma_request <= HIGH;
request_state <= STATE_REQUEST_DMA;
end
end
STATE_REQUEST_NEXT : begin
if (~&length_sum) begin
// generate a new DMA request which continues the current span
next_dma_busy = HIGH;
request_state <= STATE_REQUEST_DMA;
end
else if (count_sum > 0) begin
// generate a new DMA request for the next span
next_dma_busy = HIGH;
// advance the DMA address
slave_address_adder0 = slave_address_sum;
slave_address_adder1 = skip_pl;
slave_address_adder2 = LOW;
length_adder0 = length_pl;
length_adder1 = -1;
decrement_count = HIGH;
request_state <= STATE_REQUEST_DMA;
end
else if (io_read_full || io_write_full) begin
io_valid <= HIGH;
request_state <= STATE_REQUEST_IO;
end
else if (dma_full) begin
slave_address_adder0 = slave_address;
slave_address_adder1 = 0;
slave_address_adder2 = LOW;
master_address_adder0 = master_address;
master_address_adder1 = -1;
length_adder0 = length;
length_adder1 = -1;
load_count = HIGH;
next_dma_full = LOW;
next_dma_busy = HIGH;
skip_pl <= skip;
length_pl <= length;
read_pl <= read;
imem_select_pl <= master_imem_select;
dma_request <= HIGH;
request_state <= STATE_REQUEST_DMA;
end
else begin
request_state <= STATE_REQUEST_IDLE;
end
end
default : begin
request_state <= 'bx;
$display("Panic! Unknown MSP request state - <%d>", request_state);
$finish;
end
endcase
// DMA transfer state machine
case (dma_state)
STATE_DMA_IDLE : begin
if (dma_valid) begin
next_mem_busy = HIGH;
if (dma_start) begin
load_dma_mem_address = HIGH;
dma_valid <= LOW;
if (dma_read_pl) begin
next_mem_write = HIGH;
next_mem_mask = -1;
if (dma_last) begin
if (dma_valid) begin
next_dma_busy = HIGH;
end
dma_state <= STATE_DMA_IDLE;
end
else begin
next_dma_busy = HIGH;
dma_state <= STATE_READ_SECONDARY;
end
end
else begin
next_mem_read = HIGH;
if (dma_last) begin
if (dma_valid) begin
next_dma_busy = HIGH;
end
dma_state <= STATE_DMA_IDLE;
end
else begin
next_dma_busy = HIGH;
dma_state <= STATE_WRITE_SECONDARY;
end
end
end
else begin
next_dma_busy = HIGH;
dma_state <= STATE_DMA_IDLE;
end
end
else begin
dma_state <= STATE_DMA_IDLE;
end
end
STATE_WRITE_PRIMARY : begin
next_mem_read = HIGH;
next_mem_busy = HIGH;
if (dma_last) begin
if (dma_valid) begin
next_dma_busy = HIGH;
end
dma_state <= STATE_DMA_IDLE;
end
else begin
next_dma_busy = HIGH;
dma_state <= STATE_WRITE_SECONDARY;
end
end
STATE_WRITE_SECONDARY : begin
if (imem_select) begin
next_mem_read = HIGH;
end
if (dma_last) begin
if (dma_valid) begin
next_dma_busy = HIGH;
next_mem_busy = HIGH;
end
dma_state <= STATE_DMA_IDLE;
end
else begin
next_dma_busy = HIGH;
next_mem_busy = HIGH;
dma_state <= STATE_WRITE_PRIMARY;
end
end
STATE_READ_PRIMARY : begin
next_mem_write = HIGH;
next_mem_mask = -1;
next_mem_busy = HIGH;
if (dma_last) begin
if (dma_valid) begin
next_dma_busy = HIGH;
end
dma_state <= STATE_DMA_IDLE;
end
else begin
next_dma_busy = HIGH;
dma_state <= STATE_READ_SECONDARY;
end
end
STATE_READ_SECONDARY : begin
next_mem_mask = -1;
if (imem_select) begin
next_mem_write = HIGH;
end
if (dma_last) begin
if (dma_valid) begin
next_dma_busy = HIGH;
next_mem_busy = HIGH;
end
dma_state <= STATE_DMA_IDLE;
end
else begin
next_dma_busy = HIGH;
next_mem_busy = HIGH;
dma_state <= STATE_READ_PRIMARY;
end
end
default: begin
dma_state <= 'bx;
$display("Panic! Unknown MSP DMA state - <%d>", dma_state);
$finish;
end
endcase
// CMDBUF state machine
case (cmd_state)
STATE_CMD_PRIMARY : begin
if (cmd_read && cmd_ready) begin
// read from DMEM into CMDBUF
next_mem_read = HIGH;
cmd_state <= STATE_CMD_SECONDARY;
end
else begin
cmd_state <= STATE_CMD_PRIMARY;
end
end
STATE_CMD_SECONDARY : begin
cmd_state <= STATE_CMD_PRIMARY;
end
default : begin
cmd_state <= 'bx;
end
endcase
// IO MEM read/write state machine
// An IO read may occur during an IO write, but not vice-versa.
// Therefore, if we always give IO write preference, we will
// always execute in-order without preemption. Also, a write
// will not occur during a write nor will a read occur during
// a read.
case (io_state)
STATE_IO_IDLE : begin
if (io_valid && !mem_busy) begin
load_io_mem_address = HIGH;
if (io_write_full) begin
if (next_io_imem_select) begin
next_mem_read = HIGH;
io_state <= STATE_IO_IMEM_WRITE_1;
end
else begin
next_mem_write = HIGH;
if (next_io_word_select) begin
next_mem_mask = 2'b01;
end
else begin
next_mem_mask = 2'b10;
end
io_state <= STATE_IO_WRITE;
end
end
else begin
next_mem_read = HIGH;
io_state <= STATE_IO_READ_1;
end
end
else begin
io_state <= STATE_IO_IDLE;
end
end
STATE_IO_READ_1 : begin
io_valid <= LOW;
io_read_full <= LOW;
io_state <= STATE_IO_READ_2;
end
STATE_IO_READ_2 : begin
io_state <= STATE_IO_READ_3;
end
STATE_IO_READ_3 : begin
next_mem_load = HIGH;
io_state <= STATE_IO_IDLE;
end
STATE_IO_IMEM_WRITE_1 : begin
io_state <= STATE_IO_IMEM_WRITE_2;
end
STATE_IO_IMEM_WRITE_2 : begin
io_state <= STATE_IO_IMEM_WRITE_3;
end
STATE_IO_IMEM_WRITE_3 : begin
load_io_mem_address = HIGH;
next_mem_write = HIGH;
io_state <= STATE_IO_WRITE;
end
STATE_IO_WRITE : begin
io_valid <= LOW;
io_write_full <= LOW;
io_state <= STATE_IO_IDLE;
end
default : begin
io_state <= 'bx;
end
endcase
pc_write <= next_pc_write;
mem_read <= next_mem_read;
mem_write <= next_mem_write;
mem_load <= next_mem_load;
dma_full <= next_dma_full;
dma_busy <= next_dma_busy || next_dma_full;
mem_busy <= next_mem_busy;
bist_done_reg <= next_bist_done;
bist_fail_reg <= next_bist_fail;
cpu_semaphore_read <= next_cpu_semaphore_read;
cpu_semaphore_write <= next_cpu_semaphore_write;
semaphore <= cp0_semaphore_read || cpu_semaphore_read
|| (!cp0_semaphore_write && !cpu_semaphore_write && semaphore);
if (cpu_semaphore_read) begin
cpu_semaphore <= (semaphore && !cp0_semaphore_write)
|| cp0_semaphore_read;
end
case ({set_broke, clear_broke})
2'b10 : begin
broke <= HIGH;
set_halt = HIGH;
if (interrupt_on_break) begin
set_interrupt = HIGH;
end
end
2'b01 : broke <= LOW;
endcase
case ({set_halt, clear_halt})
2'b10 : halt <= HIGH;
2'b01 : halt <= LOW;
endcase
case ({set_interrupt, clear_interrupt})
2'b10 : interrupt <= HIGH;
2'b01 : interrupt <= LOW;
endcase
case ({set_single_step, clear_single_step})
2'b10 : single_step <= HIGH;
2'b01 : single_step <= LOW;
endcase
begin : signal_block
integer i;
for (i = 0; i < SP_SIGNAL_SIZE; i = i + 1) begin
case ({set_signal[i], clear_signal[i]})
2'b10 : signal[i] <= HIGH;
2'b01 : signal[i] <= LOW;
endcase
end
end
case ({set_interrupt_on_break, clear_interrupt_on_break})
2'b10 : interrupt_on_break <= HIGH;
2'b01 : interrupt_on_break <= LOW;
endcase
reg_read_request <= next_reg_read_request;
mem_read_request <= next_mem_read_request;
master_address_sum <= master_address_adder0+master_address_adder1+1;
slave_address_sum <= slave_address_adder0
+ slave_address_adder1
+ slave_address_adder2;
length_sum <= length_adder0 + ~length_adder1;
mem_address <= mem_address_sum;
if (load_count) begin
count_sum <= count;
end
else if (decrement_count) begin
count_sum <= count_sum - 1;
end
// dma adders
if (cmd_read && cmd_ready) begin
imem_select <= LOW;
mem_address_sum <= cmd_address;
end
else if (load_io_mem_address) begin
io_write_select <= HIGH;
io_read_select <= next_io_word_select;
imem_select <= next_io_imem_select;
mem_address_sum <= next_io_mem_address;
end
else if (load_dma_mem_address) begin
io_write_select <= LOW;
imem_select <= dma_imem_select_pl;
mem_address_sum <= dma_mem_address_pl;
end
else begin
mem_address_sum <= mem_address_sum + 1;
end
// dmem write mask
mem_mask <= next_mem_mask;
end
end
endmodule