diff --git a/utils/hwstub/tools/lua/atj.lua b/utils/hwstub/tools/lua/atj.lua
index 1f59a141fc..a1ad0c7505 100644
--- a/utils/hwstub/tools/lua/atj.lua
+++ b/utils/hwstub/tools/lua/atj.lua
@@ -7,3 +7,4 @@ ATJ = {}
 hwstub.soc:select("atj213x")
 require "atj/gpio"
 require "atj/lcm"
+require "atj/dsp"
diff --git a/utils/hwstub/tools/lua/atj/dsp.lua b/utils/hwstub/tools/lua/atj/dsp.lua
new file mode 100644
index 0000000000..93c80e36ef
--- /dev/null
+++ b/utils/hwstub/tools/lua/atj/dsp.lua
@@ -0,0 +1,158 @@
+ATJ.dsp = {}
+
+-- Ungate DSP clock
+function ATJ.dsp.init()
+    HW.CMU.DEVCLKEN.write(bit32.bor(HW.CMU.DEVCLKEN.read(), 0x10010))
+end
+
+-- Connect memory to DSP bus
+-- Start DSP core
+function ATJ.dsp.start()
+    HW.SRAMOC.CTL.write(0)  -- connect memory to DSP bus
+    HW.DSP.CTL.write(0x187) -- reset DSP
+    hwstub.mdelay(100)
+    HW.DSP.CTL.write(0x18f) -- run DSP from PM@0 clocked from HOSC
+end
+
+-- Stop DSP core
+-- Connect memory to MIPS bus
+function ATJ.dsp.stop()
+    HW.DSP.CTL.write(0x107)
+    HW.DSP.CTL.write(0x0f)
+    HW.SRAMOC.CTL.write(0xf0) -- connect memory to MIPS bus
+end
+
+function ATJ.dsp.setclock(mhz)
+    local dpck = math.floor(mhz/6)
+    if dpck < 2 then dpck = 2 end
+
+    HW.DSP.CTL.write(0x0f)         -- stop DSP clock
+    HW.CMU.DSPPLL.DPCK.write(dpck) -- setup pll
+    HW.CMU.DSPPLL.DPEN.write(1)    -- enable pll
+    hwstub.mdelay(10)              -- wait for PLL to settle
+    HW.DSP.CTL.write(0x10f)        -- run DSP again clocked from DSP PLL
+end
+
+-- Start the execution of DSP program and wait
+-- specified number of miliseconds before stoping DSP
+-- Then you can inspect DSP memories from MIPS side
+function ATJ.dsp.run(msec)
+    DSP.stop()
+    DSP.start()
+    hwstub.mdelay(msec)
+    DSP.stop()
+end
+
+-- Clear DSP program memory
+function ATJ.dsp.clearPM()
+    DSP.stop()
+    for i=0,16*1024-1,4 do DEV.write32(0xb4040000+i, 0) end
+end
+
+-- Clear DSP data memory
+function ATJ.dsp.clearDM()
+    DSP.stop()
+    for i=0,16*1024-1,4 do DEV.write32(0xb4050000+i, 0) end
+end
+
+-- write single 24bit value to DSP memory
+-- 0xb4040000 is start address of PM
+-- 0xb4050000 is start address of DM
+function ATJ.dsp.write(addr,val)
+    DEV.write8(addr+0, bit32.band(val, 0xff))
+    DEV.write8(addr+1, bit32.band(bit32.rshift(val, 8), 0xff))
+    DEV.write8(addr+2, bit32.band(bit32.rshift(val, 16), 0xff))
+end
+
+-- This function takes array of opcodes/values and writes it DSP memory
+function ATJ.dsp.prog(opcodes, base, type)
+    if base > 0x3fff then
+         print(string.format("Invalid address 0x%x", base))
+         return
+    end
+
+    if type == 'p' then
+         -- DSP program memory
+         base = base + 0xb4040000
+    elseif type == 'd' then
+         -- DSP data memory
+         base = base + 0xb4050000
+    else
+        print(string.format("Invalid memory type: %c", type))
+        return
+    end
+
+    local offset=0
+    DSP.stop()
+    for i,opcode in ipairs(opcodes) do
+        DSP.write(base+4*offset, opcode)
+        offset=offset+1
+    end
+end
+
+-- This function reads the file produced by as2181 and
+-- uploads it to the DSP memory
+function ATJ.dsp.progfile(path)
+    local opcodes={}
+    local addr=nil
+    local type=nil
+
+    local fh=io.open(path)
+    if fh == nil then
+        print(string.format("Unable to open %s", path))
+        return
+    end
+
+    while true do
+        line = fh:read()
+        if line == nil then
+            break
+        end
+
+        -- Search for header describing target memory
+        if string.find(line, '@PA') ~= nil then
+            type = 'p'
+        elseif string.find(line, '@PD' ~= nil) then
+            type = 'd'
+         end
+
+         if type ~= nil then
+            -- Next line after the header is the address
+            addr = fh:read()
+            if addr ~= nil then
+                addr = tonumber(addr, 16)
+            else
+                break;
+            end
+
+            while true do
+                line = fh:read()
+                if line == nil then
+                    break
+                end
+
+                 -- Check ending clause
+                 -- We don't check embedded checksum
+                 if string.find(line, '#123') then
+                     break
+                 end
+
+                 -- Read operand and store in array
+                 opcodes[#opcodes+1] = tonumber(line,16)
+             end
+
+             if (type == 'p') then
+                 print(string.format("Writing %d opcodes PM @ 0x%0x", #opcodes, addr))
+             elseif (type == 'd') then
+                 print(string.format("Writing %d values DM @ x0%0x", #opcodes, addr))
+             end
+
+             -- Write to DSP memory
+             DSP.prog(opcodes, addr, type)
+             opcodes={}
+             addr = nil
+             type = nil
+         end
+    end
+    fh:close()
+end