design/sys/iop/niu/rtl/xpcs_rxio_sync.v

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//
// OpenSPARC T2 Processor File: xpcs_rxio_sync.v
// Copyright (C) 1995-2007 Sun Microsystems, Inc. All Rights Reserved
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// ****************************************************************
//
//   Sun Proprietary/Confidential: Internal Use Only
//
// ****************************************************************
//   Design: IB Phy Interface Core
//    Block: IB Phy Interface Core Top Level
//   Author: Carlos Castil
//
//   Module: xpcs_rxio_sync
//     File: xpcs_rxio_sync.v
//
//   Description: This block contains an X12 receive physical
//                channel.
//
//   Revision History
//   ------------------------------------------------------------
//      Ver   Date      Comments
//   ------------------------------------------------------------
//      1.0   09/21/02  Created
//
// ****************************************************************

module xpcs_rxio_sync (
                rx_clk,

                reset_rxclk,
                reset_rxclk_lane,

                flush,

                rx_signal_detect,

                hold,

                byte_out,
                special_out,
                error_out,

                symbol_in,

                csr_lane_sync_state,
                csr_lane_sync_status,

                rx_lane_clk);

// RX Link Interface

input           rx_clk;
input           rx_signal_detect;
input           reset_rxclk;
input           reset_rxclk_lane;
input           rx_lane_clk;
input           flush;

input           hold;

input   [9:0]   symbol_in;

output  [7:0]   byte_out;
output          special_out;
output          error_out;

output          csr_lane_sync_status;
output  [3:0]   csr_lane_sync_state;

// Wires

wire            rx_lane_clk;

wire [7:0]      byte_deskew;
wire            special_deskew;
wire            error_deskew;

wire [2:0]      w_ptr;
wire [2:0]      r_ptr;

reg             flush_d;

wire            flush_hold;
wire            flush_sync;


// **********************************************
// Synchronize flush from rx_clk to rx lane clk
// **********************************************

 always @ (posedge rx_clk)
    flush_d <= flush;

 assign flush_hold = flush | flush_d;

 SYNC_CELL FLUSH_SYNC (.D(flush_hold),
                            .CP(rx_lane_clk),
                            .Q(flush_sync));

xpcs_rxio_sync_fifo_ptr xpcs_rxio_sync_fifo_ptr (
                .w_clk   (rx_lane_clk),
                .w_rst   (reset_rxclk_lane),

                .rx_clk (rx_clk),

                .w_ptr   (w_ptr),
                .r_ptr   (r_ptr),

                .hold    (hold),

                .rst     (reset_rxclk),
                .flush   (flush) );


// 10b/8b decoder for low byte

xpcs_rxio_sync_decoder xpcs_rxio_sync_decode (
                .rx_lane_clk    (rx_lane_clk),
                .rx_lane_reset  (reset_rxclk_lane),

                .rx_symbol      (symbol_in),

                .byte           (byte_deskew),
                .special        (special_deskew),
                .error          (error_deskew));

// Synchronization State Machine

xpcs_rxio_sync_sm xpcs_rxio_sync_sm (
                .rx_lane_clk          (rx_lane_clk),
                .rx_signal_detect     (rx_signal_detect),
                .rx_lane_reset        (reset_rxclk_lane),

                .byte_deskew          (byte_deskew),      // Before synchronization on lane clock
                .special_deskew       (special_deskew),
                .error_deskew         (error_deskew),

                .state                (csr_lane_sync_state),
                .csr_lane_sync_status (csr_lane_sync_status));

// deskew fifo for low byte stream

xpcs_rxio_sync_deskew_fifo xpcs_rxio_sync_deskew_fifo (
                .w_clk                  (rx_lane_clk),
                .w_rst                  (reset_rxclk_lane | flush_sync),

                .w_byte                 (byte_deskew),   // Before synchronization on lane clock
                .w_special              (special_deskew),
                .w_error                (error_deskew),

                .w_ptr                  (w_ptr),
                .r_ptr                  (r_ptr),         // read ptr synchronized to rx_clk

                .byte                   (byte_out),      // data synchronized to rx_clk
                .special                (special_out),
                .error                  (error_out));

endmodule