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URL https://opencores.org/ocsvn/amber/amber/trunk

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    from Rev 29 to Rev 30
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Rev 29 → Rev 30

/amber/trunk/hw/vlog/amber25/a25_wishbone.v
141,18 → 141,26
wire icache_read_ready;
reg servicing_dcache_cached_read_r = 'd0;
reg servicing_dcache_uncached_read_r = 'd0;
reg servicing_dcache_cached_write_r = 'd0;
reg servicing_dcache_uncached_write_r = 'd0;
reg servicing_icache_r = 'd0;
wire extra_write;
reg extra_write_r = 'd0;
reg [31:0] extra_write_data_r;
reg [31:0] extra_write_address_r;
reg [3:0] extra_write_be_r;
wire buffer_write;
reg buffer_write_r = 'd0;
reg [31:0] buffer_write_data_r;
reg [31:0] buffer_write_address_r;
reg [3:0] buffer_write_be_r;
wire write_ack;
 
 
assign read_ack = !o_wb_we && i_wb_ack;
 
assign dcache_cached_rready = dcache_cached_rreq_r && servicing_dcache_cached_read_r && read_ack;
assign dcache_uncached_rready = dcache_uncached_rreq_r && servicing_dcache_uncached_read_r && read_ack;
 
assign dcache_cached_wready = (dcache_cached_wreq_c && wishbone_st == WB_IDLE && !dcache_cached_rreq_c) ||
(servicing_dcache_cached_write_r && i_wb_ack && wishbone_st == WB_WAIT_ACK && !dcache_cached_rreq_c);
assign dcache_uncached_wready = (dcache_uncached_wreq_c && wishbone_st == WB_IDLE && !dcache_uncached_rreq_c) ||
(servicing_dcache_uncached_write_r && i_wb_ack && wishbone_st == WB_WAIT_ACK && !dcache_uncached_rreq_c);
 
assign o_dcache_cached_ready = dcache_cached_rready || dcache_cached_wready;
assign o_dcache_uncached_ready = dcache_uncached_rready || dcache_uncached_wready;
162,7 → 170,6
assign o_icache_ready = icache_read_ready;
assign o_icache_read_data = i_wb_dat;
 
 
assign dcache_cached_rreq_in = i_dcache_cached_req && !i_dcache_write;
assign dcache_cached_wreq_in = i_dcache_cached_req && i_dcache_write;
assign dcache_uncached_rreq_in = i_dcache_uncached_req && !i_dcache_write;
186,9 → 193,6
// For writes the byte enable is always 4'hf
assign byte_enable = write_req_c ? i_dcache_byte_enable : 4'hf;
 
assign dcache_cached_wready = (dcache_cached_wreq_c && wishbone_st == WB_IDLE);
assign dcache_uncached_wready = (dcache_uncached_wreq_c && wishbone_st == WB_IDLE);
assign dcache_cached_wreq_c = dcache_cached_wreq_in || dcache_cached_wreq_r;
assign dcache_uncached_wreq_c = dcache_uncached_wreq_in || dcache_uncached_wreq_r;
 
197,15 → 201,9
// Register Accesses
// ======================================
 
assign extra_write = wishbone_st == WB_IDLE && !i_wb_ack && ((dcache_cached_wreq_c && dcache_cached_wready)||
(dcache_uncached_wreq_c && dcache_uncached_wready));
assign buffer_write = dcache_cached_wreq_in || dcache_uncached_wreq_in;
assign write_buffered = dcache_uncached_wreq_r || dcache_uncached_wreq_r;
 
always @( posedge i_clk )
if ( wishbone_st == WB_WAIT_ACK && i_wb_ack && extra_write_r )
o_wb_dat <= extra_write_data_r;
else if ( start_access )
o_wb_dat <= i_dcache_write_data;
 
 
always @( posedge i_clk )
215,16 → 213,49
if ( i_icache_req ) icache_read_addr_r <= i_icache_address;
dcache_read_qword_r <= i_dcache_qword || dcache_read_qword_c;
dcache_cached_wreq_r <= dcache_cached_wreq_c && (wishbone_st != WB_IDLE || (o_wb_stb && !i_wb_ack));
dcache_uncached_wreq_r <= dcache_uncached_wreq_c && (wishbone_st != WB_IDLE || (o_wb_stb && !i_wb_ack));
// A buffer to hold a second write while on eis in progress
if ( extra_write )
 
// Buffer Write requests
case (wishbone_st)
WB_WAIT_ACK :
begin
if (servicing_dcache_uncached_write_r && i_wb_ack && !buffer_write)
dcache_uncached_wreq_r <= 1'd0;
else
dcache_uncached_wreq_r <= dcache_uncached_wreq_c;
if (servicing_dcache_cached_write_r && i_wb_ack && !buffer_write)
dcache_cached_wreq_r <= 1'd0;
else
dcache_cached_wreq_r <= dcache_cached_wreq_c;
end
WB_IDLE:
begin
if (dcache_uncached_wreq_c && o_wb_stb && !i_wb_ack)
dcache_uncached_wreq_r <= 1'd1;
else
dcache_uncached_wreq_r <= 1'd0;
if (dcache_cached_wreq_c && o_wb_stb && !i_wb_ack)
dcache_cached_wreq_r <= 1'd1;
else
dcache_cached_wreq_r <= 1'd0;
end
default:
begin
dcache_uncached_wreq_r <= dcache_uncached_wreq_c;
dcache_cached_wreq_r <= dcache_cached_wreq_c;
end
endcase
// A buffer to hold a second write while on is in progress
if ( buffer_write )
begin
extra_write_data_r <= i_dcache_write_data;
extra_write_address_r <= i_dcache_address;
extra_write_be_r <= i_dcache_byte_enable;
buffer_write_data_r <= i_dcache_write_data;
buffer_write_address_r <= i_dcache_address;
buffer_write_be_r <= i_dcache_byte_enable;
end
 
 
235,7 → 266,8
dcache_cached_rreq_r <= dcache_cached_rreq_c && !o_dcache_cached_ready;
end
else
dcache_cached_rreq_r <= dcache_cached_rreq_c && !o_dcache_cached_ready;
dcache_cached_rreq_r <= dcache_cached_rreq_c && (!o_dcache_cached_ready || dcache_cached_wreq_r);
if ( dcache_uncached_rreq_r )
begin
if ( wishbone_st == WB_IDLE || wishbone_st == WB_WAIT_ACK )
242,23 → 274,23
dcache_uncached_rreq_r <= dcache_uncached_rreq_c && !o_dcache_uncached_ready;
end
else
dcache_uncached_rreq_r <= dcache_uncached_rreq_c && !o_dcache_uncached_ready;
dcache_uncached_rreq_r <= dcache_uncached_rreq_c && (!o_dcache_uncached_ready || dcache_uncached_wreq_r);
end
assign wait_write_ack = o_wb_stb && o_wb_we && !i_wb_ack;
assign write_ack = o_wb_stb && o_wb_we && i_wb_ack;
 
 
always @( posedge i_clk )
case ( wishbone_st )
WB_IDLE :
begin
extra_write_r <= extra_write;
begin
if ( start_access )
begin
o_wb_stb <= 1'd1;
o_wb_cyc <= 1'd1;
o_wb_sel <= byte_enable;
o_wb_dat <= write_buffered ? buffer_write_data_r : i_dcache_write_data;
end
else if ( !wait_write_ack )
begin
272,9 → 304,11
if ( wait_write_ack )
begin
// still waiting for last (write) access to complete
wishbone_st <= WB_WAIT_ACK;
servicing_dcache_cached_read_r <= dcache_cached_rreq_c;
servicing_dcache_uncached_read_r <= dcache_uncached_rreq_c;
wishbone_st <= WB_WAIT_ACK;
servicing_dcache_cached_read_r <= dcache_cached_rreq_c;
servicing_dcache_uncached_read_r <= dcache_uncached_rreq_c;
servicing_dcache_cached_write_r <= dcache_cached_wreq_c;
servicing_dcache_uncached_write_r <= dcache_uncached_wreq_c;
end
// dcache accesses have priority over icache
else if ( dcache_cached_rreq_c || dcache_uncached_rreq_c )
372,15 → 406,23
// Wait for the wishbone ack to be asserted
WB_WAIT_ACK:
if ( i_wb_ack )
begin
servicing_dcache_cached_read_r <= 1'd0;
servicing_dcache_uncached_read_r <= 1'd0;
servicing_dcache_cached_write_r <= 1'd0;
servicing_dcache_uncached_write_r <= 1'd0;
servicing_icache_r <= 1'd0;
// Another write that was acked and needs to be sent before returning to IDLE ?
if ( extra_write_r )
if ( write_buffered )
begin
extra_write_r <= 'd0;
wishbone_st <= WB_IDLE;
o_wb_stb <= 1'd1;
o_wb_cyc <= exclusive_access;
o_wb_sel <= extra_write_be_r;
o_wb_sel <= buffer_write_be_r;
o_wb_we <= 1'd1;
o_wb_adr[31:0] <= extra_write_address_r;
o_wb_adr[31:0] <= buffer_write_address_r;
o_wb_dat <= buffer_write_data_r;
end
else
begin
388,11 → 430,8
o_wb_stb <= 1'd0;
o_wb_cyc <= exclusive_access;
o_wb_we <= 1'd0;
servicing_dcache_cached_read_r <= 1'd0;
servicing_dcache_uncached_read_r <= 1'd0;
servicing_icache_r <= 1'd0;
end
end
endcase
 

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