atahost_wb_slave.vhd

硬盘接口的硬件实现

		process(clk_i)
		begin
			if (clk_i'event and clk_i = '1') then
				if (PIOsel = '0') then
					store_pp_full <= PIOpp_full;
				end if;
			end if;
		end process;
		brty <= (ATA_DEV_ADR and w_acc) and (DMAtip or store_pp_full);
	end block gen_bc_dec;

	--
	-- generate registers
	--
	register_block : block
		signal sel_PIO_cmdport, sel_PIO_dport0, sel_PIO_dport1 : std_logic; -- PIO timing registers
		signal sel_DMA_dev0, sel_DMA_dev1 : std_logic;                      -- DMA timing registers
		signal sel_ctrl, sel_stat : std_logic;                              -- control / status register
	begin
		-- generate register select signals
		sel_ctrl        <= CONsel and we_i and (ATA_ADR = ATA_CTRL_REG);
		sel_stat        <= CONsel and we_i and (ATA_ADR = ATA_STAT_REG);
		sel_PIO_cmdport <= CONsel and we_i and (ATA_ADR = ATA_PIO_CMD);
		sel_PIO_dport0  <= CONsel and we_i and (ATA_ADR = ATA_PIO_DP0);
		sel_PIO_dport1  <= CONsel and we_i and (ATA_ADR = ATA_PIO_DP1);
		sel_DMA_dev0    <= CONsel and we_i and (ATA_ADR = ATA_DMA_DEV0);
		sel_DMA_dev1    <= CONsel and we_i and (ATA_ADR = ATA_DMA_DEV1);
		-- reserved 0x1C-0x38 --
		-- reserved 0x3C : DMA port --

		-- generate control register
		gen_ctrl_reg: process(clk_i, arst_i)
		begin
			if (arst_i = '0') then
				CtrlReg(31 downto 1) <= (others => '0');
				CtrlReg(0)           <= '1';                -- set reset bit
			elsif (clk_i'event and clk_i = '1') then
				if (rst_i = '1') then
					CtrlReg(31 downto 1) <= (others => '0');
					CtrlReg(0)           <= '1';                -- set reset bit
				elsif (sel_ctrl = '1') then
					CtrlReg <= dat_i;
				end if;
			end if;
		end process gen_ctrl_reg;
		-- assign bits
		DMActrl_DMAen        <= CtrlReg(15);
		DMActrl_dir          <= CtrlReg(13);
		DMActrl_BeLeC1       <= CtrlReg(9);
		DMActrl_BeLeC0       <= CtrlReg(8);
		IDEctrl_IDEen        <= CtrlReg(7);
		IDEctrl_FATR1        <= CtrlReg(6);
		IDEctrl_FATR0        <= CtrlReg(5);
		IDEctrl_ppen         <= CtrlReg(4);
		PIO_dport1_IORDYen   <= CtrlReg(3);
		PIO_dport0_IORDYen   <= CtrlReg(2);
		PIO_cmdport_IORDYen  <= CtrlReg(1);
		IDEctrl_rst          <= CtrlReg(0);

		-- generate status register clearable bits
		gen_stat_reg: block
			signal dirq, int : std_logic;
		begin
			gen_irq: process(clk_i, arst_i)
			begin
				if (arst_i = '0') then
					int  <= '0';
					dirq <= '0';
				elsif (clk_i'event and clk_i = '1') then
					if (rst_i = '1') then
						int  <= '0';
						dirq <= '0';
					else
						int  <= (int or (irq and not dirq)) and not (sel_stat and not dat_i(0));
						dirq <= irq;
					end if;
				end if;
			end process gen_irq;

			gen_stat: process(DMAtip, DMARxEmpty, DMATxFull, DMA_dmarq, PIOtip, int, PIOpp_full)
			begin
				StatReg(31 downto 0) <= (others => '0');                -- clear all bits (read unused bits as '0')

				StatReg(31 downto 28) <= std_logic_vector(DeviceId);    -- set Device ID
				StatReg(27 downto 24) <= std_logic_vector(RevisionNo);  -- set revision number
				StatReg(15) <= DMAtip;
				StatReg(10) <= DMARxEmpty;
				StatReg(9)  <= DMATxFull;
				StatReg(8)  <= DMA_dmarq;
				StatReg(7)  <= PIOtip;
				StatReg(6)  <= PIOpp_full;
				StatReg(0)  <= int;
			end process;
		end block gen_stat_reg;

		-- generate PIO compatible / command-port timing register
		gen_PIO_cmdport_reg: process(clk_i, arst_i)
		begin
			if (arst_i = '0') then
				PIO_cmdport_T1   <= conv_unsigned(PIO_mode0_T1, 8);
				PIO_cmdport_T2   <= conv_unsigned(PIO_mode0_T2, 8);
				PIO_cmdport_T4   <= conv_unsigned(PIO_mode0_T4, 8);
				PIO_cmdport_Teoc <= conv_unsigned(PIO_mode0_Teoc, 8);
			elsif (clk_i'event and clk_i = '1') then
				if (rst_i = '1') then
					PIO_cmdport_T1   <= conv_unsigned(PIO_mode0_T1, 8);
					PIO_cmdport_T2   <= conv_unsigned(PIO_mode0_T2, 8);
					PIO_cmdport_T4   <= conv_unsigned(PIO_mode0_T4, 8);
					PIO_cmdport_Teoc <= conv_unsigned(PIO_mode0_Teoc, 8);
				elsif (sel_PIO_cmdport = '1') then
					PIO_cmdport_T1   <= unsigned(dat_i( 7 downto  0));
					PIO_cmdport_T2   <= unsigned(dat_i(15 downto  8));
					PIO_cmdport_T4   <= unsigned(dat_i(23 downto 16));
					PIO_cmdport_Teoc <= unsigned(dat_i(31 downto 24));
				end if;
			end if;
		end process gen_PIO_cmdport_reg;

		-- generate PIO device0 timing register
		gen_PIO_dport0_reg: process(clk_i, arst_i)
		begin
			if (arst_i = '0') then
				PIO_dport0_T1   <= conv_unsigned(PIO_mode0_T1, 8);
				PIO_dport0_T2   <= conv_unsigned(PIO_mode0_T2, 8);
				PIO_dport0_T4   <= conv_unsigned(PIO_mode0_T4, 8);
				PIO_dport0_Teoc <= conv_unsigned(PIO_mode0_Teoc, 8);
			elsif (clk_i'event and clk_i = '1') then
				if (rst_i = '1') then
					PIO_dport0_T1   <= conv_unsigned(PIO_mode0_T1, 8);
					PIO_dport0_T2   <= conv_unsigned(PIO_mode0_T2, 8);
					PIO_dport0_T4   <= conv_unsigned(PIO_mode0_T4, 8);
					PIO_dport0_Teoc <= conv_unsigned(PIO_mode0_Teoc, 8);
				elsif (sel_PIO_dport0 = '1') then
					PIO_dport0_T1   <= unsigned(dat_i( 7 downto  0));
					PIO_dport0_T2   <= unsigned(dat_i(15 downto  8));
					PIO_dport0_T4   <= unsigned(dat_i(23 downto 16));
					PIO_dport0_Teoc <= unsigned(dat_i(31 downto 24));
				end if;
			end if;
		end process gen_PIO_dport0_reg;

		-- generate PIO device1 timing register
		gen_PIO_dport1_reg: process(clk_i, arst_i)
		begin
			if (arst_i = '0') then
				PIO_dport1_T1   <= conv_unsigned(PIO_mode0_T1, 8);
				PIO_dport1_T2   <= conv_unsigned(PIO_mode0_T2, 8);
				PIO_dport1_T4   <= conv_unsigned(PIO_mode0_T4, 8);
				PIO_dport1_Teoc <= conv_unsigned(PIO_mode0_Teoc, 8);
			elsif (clk_i'event and clk_i = '1') then
				if (rst_i = '1') then
					PIO_dport1_T1   <= conv_unsigned(PIO_mode0_T1, 8);
					PIO_dport1_T2   <= conv_unsigned(PIO_mode0_T2, 8);
					PIO_dport1_T4   <= conv_unsigned(PIO_mode0_T4, 8);
					PIO_dport1_Teoc <= conv_unsigned(PIO_mode0_Teoc, 8);
				elsif (sel_PIO_dport1 = '1') then
					PIO_dport1_T1   <= unsigned(dat_i( 7 downto  0));
					PIO_dport1_T2   <= unsigned(dat_i(15 downto  8));
					PIO_dport1_T4   <= unsigned(dat_i(23 downto 16));
					PIO_dport1_Teoc <= unsigned(dat_i(31 downto 24));
				end if;
			end if;
		end process gen_PIO_dport1_reg;

		-- generate DMA device0 timing register
		gen_DMA_dev0_reg: process(clk_i, arst_i)
		begin
			if (arst_i = '0') then
				DMA_dev0_Tm   <= conv_unsigned(DMA_mode0_Tm, 8);
				DMA_dev0_Td   <= conv_unsigned(DMA_mode0_Td, 8);
				DMA_dev0_Teoc <= conv_unsigned(DMA_mode0_Teoc, 8);
			elsif (clk_i'event and clk_i = '1') then
				if (rst_i = '1') then
					DMA_dev0_Tm   <= conv_unsigned(DMA_mode0_Tm, 8);
					DMA_dev0_Td   <= conv_unsigned(DMA_mode0_Td, 8);
					DMA_dev0_Teoc <= conv_unsigned(DMA_mode0_Teoc, 8);
				elsif (sel_DMA_dev0 = '1') then
					DMA_dev0_Tm   <= unsigned(dat_i( 7 downto  0));
					DMA_dev0_Td   <= unsigned(dat_i(15 downto  8));
					DMA_dev0_Teoc <= unsigned(dat_i(31 downto 24));
				end if;
			end if;
		end process gen_DMA_dev0_reg;

		-- generate DMA device1 timing register
		gen_DMA_dev1_reg: process(clk_i, arst_i)
		begin
			if (arst_i = '0') then
				DMA_dev1_Tm   <= conv_unsigned(DMA_mode0_Tm, 8);
				DMA_dev1_Td   <= conv_unsigned(DMA_mode0_Td, 8);
				DMA_dev1_Teoc <= conv_unsigned(DMA_mode0_Teoc, 8);
			elsif (clk_i'event and clk_i = '1') then
				if (rst_i = '1') then
					DMA_dev1_Tm   <= conv_unsigned(DMA_mode0_Tm, 8);
					DMA_dev1_Td   <= conv_unsigned(DMA_mode0_Td, 8);
					DMA_dev1_Teoc <= conv_unsigned(DMA_mode0_Teoc, 8);
				elsif (sel_DMA_dev1 = '1') then
					DMA_dev1_Tm   <= unsigned(dat_i( 7 downto  0));
					DMA_dev1_Td   <= unsigned(dat_i(15 downto  8));
					DMA_dev1_Teoc <= unsigned(dat_i(31 downto 24));
				end if;
			end if;
		end process gen_DMA_dev1_reg;

	end block register_block;

	--
	-- generate WISHBONE interconnect signals
	--
	gen_WB_sigs: block
		signal Q : std_logic_vector(31 downto 0);
	begin
		-- generate acknowledge signal
		ack_o <= PIOack or CONsel; -- or DMAack; -- since DMAack is derived from CONsel this is OK

		-- generate error signal
		err_o <= cyc_i and stb_i and berr;

		-- generate retry signal
		rty_o <= cyc_i and stb_i and brty;

		-- assign interrupt signal
		inta_o <= StatReg(0);
	
		-- generate output multiplexor
		with ATA_ADR select
			Q <= CtrlReg when ATA_CTRL_REG, -- control register
			     StatReg when ATA_STAT_REG, -- status register
			     std_logic_vector(PIO_cmdport_Teoc & PIO_cmdport_T4 & PIO_cmdport_T2 & PIO_cmdport_T1) when ATA_PIO_CMD,  -- PIO compatible / cmd-port timing register
			     std_logic_vector(PIO_dport0_Teoc & PIO_dport0_T4 & PIO_dport0_T2 & PIO_dport0_T1)     when ATA_PIO_DP0,  -- PIO fast timing register device0
			     std_logic_vector(PIO_dport1_Teoc & PIO_dport1_T4 & PIO_dport1_T2 & PIO_dport1_T1)     when ATA_PIO_DP1,  -- PIO fast timing register device1
			     std_logic_vector(DMA_dev0_Teoc & x"00" & DMA_dev0_Td & DMA_dev0_Tm)                   when ATA_DMA_DEV0, -- DMA timing register device0
			     std_logic_vector(DMA_dev1_Teoc & x"00" & DMA_dev1_Td & DMA_dev1_Tm)                   when ATA_DMA_DEV1, -- DMA timing register device1
			     DMAq    when ATA_DMA_PORT, -- DMA port, DMA receive register
		       (others => '0') when others;

		dat_o <= (x"0000" & PIOq) when (ATA_DEV_ADR = '1') else Q;
	end block gen_WB_sigs;

end architecture structural;