Error when using altera_mf lib

[albydnc]

When I try to process a test entity instantiating a scfifo from the altera_mf library I get this error.

ERROR LOG:

ghdl --std=08 -P=altera/ -fsynopsys  test.vhdl -e test
1. Executing GHDL.
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45938:9:error: clocked logic requires clocked logic on else part
        elsif (clock'event and (clock = '0'))
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45221:5:error: latch infered for net "n29.max_widthu" (use --latches)
    process (clock, aclr)
    ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45221:5:error: latch infered for net "n29.numwords_minus_one" (use --latches)
    process (clock, aclr)
    ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45221:5:error: latch infered for net "n29.need_init" (use --latches)
    process (clock, aclr)
    ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45234:14:warning: variable "stratix_family" is never assigned [-Wnowrite]
    variable stratix_family         : boolean := (  FEATURE_FAMILY_STRATIX(intended_device_family) ) ;
             ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45235:14:warning: variable "showahead_area" is never assigned [-Wnowrite]
    variable showahead_area         : boolean := (lpm_showahead = "ON" and add_ram_output_register = "OFF");
             ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45236:14:warning: variable "showahead_speed" is never assigned [-Wnowrite]
    variable showahead_speed        : boolean := (lpm_showahead = "ON" and add_ram_output_register = "ON");
             ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45237:14:warning: variable "legacy_speed" is never assigned [-Wnowrite]
    variable legacy_speed           : boolean := (lpm_showahead = "OFF" and add_ram_output_register = "ON");
             ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: synchronous code does not expect else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
/home/albertoperro/projects/scratch/fake_quartus/eda/sim_lib/./altera_mf.vhd:45351:9:error: clocked logic requires clocked logic on else part
        if (clock'event and (clock = '1') and
        ^
ERROR: vhdl import failed.

minimum example

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use ieee.math_real.all;

LIBRARY altera_mf;
USE altera_mf.altera_mf_components.all;

entity test is
  port (
    clk     : in std_logic;
    rst     : in std_logic;
    re     : in std_logic;
    we     : in std_logic;
    src_in  : in std_logic_vector(255 downto 0);
    src_out : out std_logic_vector(255 downto 0)
  );
end entity;

architecture rtl of test is

begin

  scfifo_rx : entity altera_mf.scfifo
  generic map (
    lpm_width => 256,
    lpm_widthu => 2,
    lpm_numwords => 2,
    lpm_showahead => "OFF",
    lpm_hint => "USE_EAB=ON",
    ram_block_type => "AUTO",
    intended_device_family => "Arria 10",
    almost_full_value => 0,
    almost_empty_value => 0,
    overflow_checking => "ON",
    underflow_checking => "ON",
    allow_rwcycle_when_full => "OFF",
    add_ram_output_register => "OFF",
    use_eab => "ON",
    lpm_type => "scfifo",
    enable_ecc => "false",
    maximum_depth => 0
  )
  port map (
    aclr => rst,
    clock => clk,
    wrreq => we,
    data => src_in,
    full => open,
    rdreq => re,
    q => src_out,
    empty => open,
    usedw => open
  );

end architecture;

[tgingold]

This scfifo is a weird as it uses double clocked process. I need to understand it first.

[tgingold]

I am not sure what could be done, except improving the error message. scfifo doesn't look to be synthesizable. Maybe Quartus handles it as a special case. The way it set the initial value is weird and certainly not conformant with 1076.6 Some signals are assigned on both clock edge.

I fear the way to move forward is to slowly rewrite altera_mf in a fully synthesizable style.

Would be interesting to know how it is handled by quartus or symplify.

[albydnc]

Sorry if I'm reviving this thread. I'm still using the altera_mf library. i wanted to use the dcfifo entity, but I got this error.

Importing module fifo.
Importing module dcfifo_48_5_10_1_1_5_5_1_d9227f9b480ae61443b6fc63d4549258851af0c8.
Importing module dcfifo_mixed_widths_48_5_48_5_10_1_1_5_5_1_97c7d795d27e3d9c8586ef5b77671f7c5d0a1c2f.
Importing module dcfifo_async_48_5_10_1_1_5_5_bc4b361abe0176cfbc009e5bd81fe2c614024365.
ERROR: Unsupported(1): instance \546 of $midff.
ERROR: Assert `GetSize(ports) >= it.second->port_id' failed in kernel/rtlil.cc:1824.

[tmeissner]

I assume that the error occurs because of you are trying to synthesize a multi-clock FF, which is not supported by yosys. See #127 for a similar issue.