Entity: spi_cmdparse

Diagram

clk_i rst_ni data_valid_i spi_byte_t data_i spi_mode_e spi_mode_i [NumCmdInfo-1:0] cmd_info_i io_mode_e io_mode_o sel_datapath_e sel_dp_o cmd_info_t cmd_info_o [CmdInfoIdxW-1:0] cmd_info_idx_o cmd_config_req_o [4:0] cmd_config_idx_o

Description

Copyright lowRISC contributors. Licensed under the Apache License, Version 2.0, see LICENSE for details. SPDX-License-Identifier: Apache-2.0

SPI Device Flash/ Passthrough mode Command Parser

This module decodes the incoming SPI Flash commands. Then activates proper downstream module.

Ports

Port name Direction Type Description
clk_i input
rst_ni input
data_valid_i input Data from spi_s2p
data_i input spi_byte_t
spi_mode_i input spi_mode_e Configurations
cmd_info_i input [NumCmdInfo-1:0] Command info slot cmdparse uses the command info slot to activate sub-datapath. It uses pre-assigned index and search opcode. e.g) if cmdslot[0].opcode == 'h03, then if received opcode matches to the cmdslot[0] opcode, then it activates Read Status module as Index 0 is pre-assigned to Read Status.
io_mode_o output io_mode_e control to spi_s2p
sel_dp_o output sel_datapath_e Activate downstream modules cmd_info_o is a registered output, latched at 8th posedge SCK
cmd_info_o output cmd_info_t
cmd_info_idx_o output [CmdInfoIdxW-1:0]
cmd_config_req_o output Command Config is not implemented yet. Indicator of command config. The pulse is generated at 3rd bit position of Opcode. The upper 5 bits are used as address to fetch command configs from DPSRAM.
cmd_config_idx_o output [4:0]

Signals

Name Type Description
unused_cmdinfo_members logic Only opcode in the cmd_info is used. Tie the rest of the members.
st st_e
st_d st_e
sel_dp sel_datapath_e ////////// Signal // //////////
latch_cmdinfo logic FSM asserts latching enable signal for cmd_info in 8th opcode cycle.
cmd_info_d cmd_info_t
cmd_info_idx_d logic [CmdInfoIdxW-1:0]
module_active logic the logic operates only when module_active condition is met
in_flashmode logic
in_passthrough logic
opcode_readstatus logic below signals are used in the FSM to determine to activate a certain datapath based on the received input (opcode). The opcode is the SW configurable CSRs cmd_info_i.
opcode_readjedec logic below signals are used in the FSM to determine to activate a certain datapath based on the received input (opcode). The opcode is the SW configurable CSRs cmd_info_i.
opcode_readsfdp logic below signals are used in the FSM to determine to activate a certain datapath based on the received input (opcode). The opcode is the SW configurable CSRs cmd_info_i.
opcode_readcmd logic below signals are used in the FSM to determine to activate a certain datapath based on the received input (opcode). The opcode is the SW configurable CSRs cmd_info_i.
upload logic Check upload field in the cmd_info

Types

Name Type Description
st_e enum logic [2:0] {
StIdle,
StStatus,
StSfdp,
StJedec,
StReadCmd,
StUpload,
StWait }		 ////////////// Definition // //////////////
spi_flash_cmd_e enum logic [7:0] {
OpReadStatus1 = 'h 05,
OpReadStatus2 = 'h 35,
OpReadStatus3 = 'h 15,
OpReadJEDEC = 'h 9F,
OpReadSfdp = 'h 5A,
OpReadNormal = 'h 03,
OpReadFast = 'h 0B,
OpReadDual = 'h 3B,
OpReadQuad = 'h 6B,
OpReadDualIO = 'h BB,
OpReadQuadIO = 'h EB }		 spi_flash_cmd_e defines HW supported (TBD for IO) commands. If received SPI Flash command falls into one of these commands, the module processes the command without SW intervention.

Processes

Type: always_comb

Type: always_comb

Type: always_ff

Description
cmd_info latch TODO: This can be furthur optimized. At 7th beat, check the opcode[7:1] with cmd_info[NumCmdInfo-1:0].opcode[7:1]. Unless SW configures more than one cmd_info slots with same opcode, at most two slots match with the opcode[7:1]. The two can be latched then at 8th beat, only the last bit of the opcode in the two cmd_info entries can be compared.
It reduces the logic from 8bit compare with 24 logic depth into 1bit compare with 1 logic depth.

Type: always_comb

Type: always_ff

Type: always_comb