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[rtl/system_integration] create individual module for AXI4 Lite bridge (
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#1063)
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@stnolting
stnolting authored Oct 18, 2024
2 parents 54bb301 + c65af0c commit 40ddbc6
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1 change: 1 addition & 0 deletions CHANGELOG.md
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Expand Up @@ -29,6 +29,7 @@ mimpid = 0x01040312 -> Version 01.04.03.12 -> v1.4.3.12

| Date | Version | Comment | Ticket |
|:----:|:-------:|:--------|:------:|
| 18.10.2024 | 1.10.5.7 | use individual/new module for XBUS-to-AXI4-Lite bridge | [#](https://github.com/stnolting/neorv32/pull/1063) |
| 12.10.2024 | 1.10.5.6 | :warning: remove legacy support for on-chip debugger DM version v0.13; now only supporting DM v1.0 (removing `OCD_DM_LEGACY_MODE` generic) | [#1056](https://github.com/stnolting/neorv32/pull/1056) |
| 11.10.2024 | 1.10.5.5 | :sparkles: :lock: add support for optional on-chip debugger authentication; :warning: rename OCD-related top generics | [#1053](https://github.com/stnolting/neorv32/pull/1053) |
| 06.10.2024 | 1.10.5.4 | :warning: rework PWM module | [#1049](https://github.com/stnolting/neorv32/pull/1049) |
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5 changes: 2 additions & 3 deletions docs/datasheet/soc_xbus.adoc
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Expand Up @@ -44,9 +44,8 @@ see section <<_address_space>>) are **redirected** to the external bus interface

.AXI4-Lite Interface Bridge
[TIP]
A processor top entity with an AXI4-Lite-compatible bus interface can be found in `rtl/system_inegration`.
More information regarding this alternate top entity can be found in in the user guide:
https://stnolting.github.io/neorv32/ug/#_packaging_the_processor_as_vivado_ip_block
A simple bridge that converts the processor's XBUS into an AXI4-lite-compatible host interface can
be found in in `rtl/system_inegration` (`xbus2axi4lite_bridge.vhd`).

.AHB3-Lite Interface Bridge
[TIP]
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2 changes: 1 addition & 1 deletion rtl/core/neorv32_package.vhd
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Expand Up @@ -29,7 +29,7 @@ package neorv32_package is

-- Architecture Constants -----------------------------------------------------------------
-- -------------------------------------------------------------------------------------------
constant hw_version_c : std_ulogic_vector(31 downto 0) := x"01100506"; -- hardware version
constant hw_version_c : std_ulogic_vector(31 downto 0) := x"01100507"; -- hardware version
constant archid_c : natural := 19; -- official RISC-V architecture ID
constant XLEN : natural := 32; -- native data path width

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3 changes: 2 additions & 1 deletion rtl/system_integration/neorv32_vivado_ip.tcl
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Expand Up @@ -48,7 +48,8 @@ puts $file_list
add_files $file_list
set_property library neorv32 [get_files $file_list]

# IP top module
# IP top module and AXI4-Lite bridge
add_file $neorv32_home/rtl/system_integration/xbus2axi4lite_bridge.vhd
add_file $neorv32_home/rtl/system_integration/$ip_top.vhd
set_property top $ip_top [current_fileset]

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223 changes: 122 additions & 101 deletions rtl/system_integration/neorv32_vivado_ip.vhd
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Expand Up @@ -256,6 +256,60 @@ architecture neorv32_vivado_ip_rtl of neorv32_vivado_ip is
constant num_xirq_c : natural := cond_sel_natural_f(XIRQ_EN, XIRQ_NUM_CH, 0);
constant num_pwm_c : natural := cond_sel_natural_f(IO_PWM_EN, IO_PWM_NUM_CH, 0);

-- AXI4-Lite bridge --
component xbus2axi4lite_bridge
port (
-- ------------------------------------------------------------
-- Global Control
-- ------------------------------------------------------------
clk : in std_logic;
resetn : in std_logic; -- low-active
-- ------------------------------------------------------------
-- XBUS Device Interface
-- ------------------------------------------------------------
xbus_adr_i : in std_ulogic_vector(31 downto 0); -- address
xbus_dat_i : in std_ulogic_vector(31 downto 0); -- write data
xbus_tag_i : in std_ulogic_vector(2 downto 0); -- access tag
xbus_we_i : in std_ulogic; -- read/write
xbus_sel_i : in std_ulogic_vector(3 downto 0); -- byte enable
xbus_stb_i : in std_ulogic; -- strobe
xbus_cyc_i : in std_ulogic; -- valid cycle
xbus_ack_o : out std_ulogic; -- transfer acknowledge
xbus_err_o : out std_ulogic; -- transfer error
xbus_dat_o : out std_ulogic_vector(31 downto 0); -- read data
-- ------------------------------------------------------------
-- AXI4-Lite Host Interface
-- ------------------------------------------------------------
-- Clock and Reset --
-- m_axi_aclk : in std_logic := '0'; -- just to satisfy Vivado, but not actually used
-- m_axi_aresetn : in std_logic := '0'; -- just to satisfy Vivado, but not actually used
-- Write Address Channel --
m_axi_awaddr : out std_logic_vector(31 downto 0);
m_axi_awprot : out std_logic_vector(2 downto 0);
m_axi_awvalid : out std_logic;
m_axi_awready : in std_logic := '0';
-- Write Data Channel --
m_axi_wdata : out std_logic_vector(31 downto 0);
m_axi_wstrb : out std_logic_vector(3 downto 0);
m_axi_wvalid : out std_logic;
m_axi_wready : in std_logic := '0';
-- Read Address Channel --
m_axi_araddr : out std_logic_vector(31 downto 0);
m_axi_arprot : out std_logic_vector(2 downto 0);
m_axi_arvalid : out std_logic;
m_axi_arready : in std_logic := '0';
-- Read Data Channel --
m_axi_rdata : in std_logic_vector(31 downto 0) := x"00000000";
m_axi_rresp : in std_logic_vector(1 downto 0) := "11"; -- error by default
m_axi_rvalid : in std_logic := '0';
m_axi_rready : out std_logic;
-- Write Response Channel --
m_axi_bresp : in std_logic_vector(1 downto 0) := "11"; -- error by default
m_axi_bvalid : in std_logic := '0';
m_axi_bready : out std_logic
);
end component;

-- type conversion --
signal jtag_tdo_aux : std_ulogic;
signal s0_axis_tdata_aux : std_ulogic_vector(31 downto 0);
Expand All @@ -279,21 +333,16 @@ architecture neorv32_vivado_ip_rtl of neorv32_vivado_ip is
signal xirq_i_aux : std_ulogic_vector(31 downto 0);

-- internal wishbone bus --
type wb_bus_t is record
adr : std_ulogic_vector(31 downto 0);
di : std_ulogic_vector(31 downto 0);
do : std_ulogic_vector(31 downto 0);
tag : std_ulogic_vector(2 downto 0);
we : std_ulogic;
sel : std_ulogic_vector(3 downto 0);
cyc : std_ulogic;
ack : std_ulogic;
err : std_ulogic;
end record;
signal wb_core : wb_bus_t;

-- AXI bridge control --
signal axi_radr_received, axi_wadr_received, axi_wdat_received : std_ulogic;
signal xbus_adr : std_ulogic_vector(31 downto 0); -- address
signal xbus_do : std_ulogic_vector(31 downto 0); -- write data
signal xbus_tag : std_ulogic_vector(2 downto 0); -- access tag
signal xbus_we : std_ulogic; -- read/write
signal xbus_sel : std_ulogic_vector(3 downto 0); -- byte enable
signal xbus_stb : std_ulogic; -- strobe
signal xbus_cyc : std_ulogic; -- valid cycle
signal xbus_di : std_ulogic_vector(31 downto 0); -- read data
signal xbus_ack : std_ulogic; -- transfer acknowledge
signal xbus_err : std_ulogic; -- transfer error

begin

Expand Down Expand Up @@ -416,16 +465,16 @@ begin
jtag_tdo_o => jtag_tdo_aux,
jtag_tms_i => std_ulogic(jtag_tms_i),
-- External bus interface (available if XBUS_EN = true) --
xbus_adr_o => wb_core.adr,
xbus_dat_o => wb_core.do,
xbus_tag_o => wb_core.tag,
xbus_we_o => wb_core.we,
xbus_sel_o => wb_core.sel,
xbus_stb_o => open,
xbus_cyc_o => wb_core.cyc,
xbus_dat_i => wb_core.di,
xbus_ack_i => wb_core.ack,
xbus_err_i => wb_core.err,
xbus_adr_o => xbus_adr,
xbus_dat_o => xbus_do,
xbus_tag_o => xbus_tag,
xbus_we_o => xbus_we,
xbus_sel_o => xbus_sel,
xbus_stb_o => xbus_stb,
xbus_cyc_o => xbus_cyc,
xbus_dat_i => xbus_di,
xbus_ack_i => xbus_ack,
xbus_err_i => xbus_err,
-- Stream Link Interface (available if IO_SLINK_EN = true) --
slink_rx_dat_i => std_ulogic_vector(s1_axis_tdata),
slink_rx_src_i => std_ulogic_vector(s1_axis_tid),
Expand Down Expand Up @@ -564,81 +613,53 @@ begin

-- Wishbone-to-AXI4-Lite Bridge -----------------------------------------------------------
-- -------------------------------------------------------------------------------------------
axi_arbiter: process(resetn, clk)
begin
if (resetn = '0') then
axi_radr_received <= '0';
axi_wadr_received <= '0';
axi_wdat_received <= '0';
elsif rising_edge(clk) then
if (wb_core.cyc = '0') then
axi_radr_received <= '0';
axi_wadr_received <= '0';
axi_wdat_received <= '0';
else -- pending access
if (wb_core.we = '0') then -- read
if (m_axi_arready = '1') then -- read address received by interconnect?
axi_radr_received <= '1';
end if;
else -- write
if (m_axi_awready = '1') then -- write address received by interconnect?
axi_wadr_received <= '1';
end if;
if (m_axi_wready = '1') then -- write data received by interconnect?
axi_wdat_received <= '1';
end if;
end if;
end if;
end if;
end process axi_arbiter;


-- read address channel --
m_axi_araddr <= std_logic_vector(wb_core.adr);
m_axi_arprot <= std_logic_vector(wb_core.tag);
m_axi_arvalid <= std_logic(wb_core.cyc and (not wb_core.we) and (not axi_radr_received));

-- read data channel --
m_axi_rready <= std_logic(wb_core.cyc and (not wb_core.we));
wb_core.di <= std_ulogic_vector(m_axi_rdata);

-- write address channel --
m_axi_awaddr <= std_logic_vector(wb_core.adr);
m_axi_awprot <= std_logic_vector(wb_core.tag);
m_axi_awvalid <= std_logic(wb_core.cyc and wb_core.we and (not axi_wadr_received));

-- write data channel --
m_axi_wdata <= std_logic_vector(wb_core.do);
m_axi_wstrb <= std_logic_vector(wb_core.sel);
m_axi_wvalid <= std_logic(wb_core.cyc and wb_core.we and (not axi_wdat_received));

-- write response channel --
m_axi_bready <= std_logic(wb_core.cyc and wb_core.we);


-- read/write response --
axi_response: process(wb_core, m_axi_bvalid, m_axi_bresp, m_axi_rvalid, m_axi_rresp)
begin
wb_core.ack <= '0'; -- default
wb_core.err <= '0'; -- default
if (wb_core.we = '1') then -- write operation
if (m_axi_bvalid = '1') then -- valid write response
if (m_axi_bresp = "00") then -- status check
wb_core.ack <= '1'; -- OK
else
wb_core.err <= '1'; -- ERROR
end if;
end if;
else -- read operation
if (m_axi_rvalid = '1') then -- valid read response
if (m_axi_rresp = "00") then -- status check
wb_core.ack <= '1'; -- OK
else
wb_core.err <= '1'; -- ERROR
end if;
end if;
end if;
end process axi_response;

axi4_bridge_inst: xbus2axi4lite_bridge
port map (
-- ------------------------------------------------------------
-- Global Control
-- ------------------------------------------------------------
clk => clk,
resetn => resetn,
-- ------------------------------------------------------------
-- XBUS Device Interface
-- ------------------------------------------------------------
xbus_adr_i => xbus_adr,
xbus_dat_i => xbus_do,
xbus_tag_i => xbus_tag,
xbus_we_i => xbus_we,
xbus_sel_i => xbus_sel,
xbus_stb_i => xbus_stb,
xbus_cyc_i => xbus_cyc,
xbus_ack_o => xbus_ack,
xbus_err_o => xbus_err,
xbus_dat_o => xbus_di,
-- ------------------------------------------------------------
-- AXI4-Lite Host Interface
-- ------------------------------------------------------------
-- Write Address Channel --
m_axi_awaddr => m_axi_awaddr,
m_axi_awprot => m_axi_awprot,
m_axi_awvalid => m_axi_awvalid,
m_axi_awready => m_axi_awready,
-- Write Data Channel --
m_axi_wdata => m_axi_wdata,
m_axi_wstrb => m_axi_wstrb,
m_axi_wvalid => m_axi_wvalid,
m_axi_wready => m_axi_wready,
-- Read Address Channel --
m_axi_araddr => m_axi_araddr,
m_axi_arprot => m_axi_arprot,
m_axi_arvalid => m_axi_arvalid,
m_axi_arready => m_axi_arready,
-- Read Data Channel --
m_axi_rdata => m_axi_rdata,
m_axi_rresp => m_axi_rresp,
m_axi_rvalid => m_axi_rvalid,
m_axi_rready => m_axi_rready,
-- Write Response Channel --
m_axi_bresp => m_axi_bresp,
m_axi_bvalid => m_axi_bvalid,
m_axi_bready => m_axi_bready
);

end architecture neorv32_vivado_ip_rtl;
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