ps.flexbus2("", ('C', 0), 0)
+We then need to generate the spec. At the top level the following command is
+then run:
+
+ $ python src/pinmux_generator.py -o i_class -s i_class
+
+Checking the resultant markdown file ./i\_class/i\_class.mdwn, we find that
+several entries have been added at the required location:
+
+| Pin | Mux0 | Mux1 | Mux2 | Mux3 |
+| --- | ----------- | ----------- | ----------- | ----------- |
+| 28 | B GPIOB_B0 | B FB_AD2 | | B EMMC_CMD |
+| 29 | B GPIOB_B1 | B FB_AD3 | | B EMMC_CLK |
+| 30 | B GPIOB_B2 | B FB_AD4 | | B EMMC_D0 |
+| 31 | B GPIOB_B3 | B FB_AD5 | | B EMMC_D1 |
+| 32 | B GPIOB_B4 | B FB_AD6 | | B EMMC_D2 |
+| 33 | B GPIOB_B5 | B FB_AD7 | | B EMMC_D3 |
+| 34 | B GPIOB_B6 | B FB_CS0 | | B EMMC_D4 |
+| 35 | B GPIOB_B7 | B FB_CS1 | | B EMMC_D5 |
+| 36 | B GPIOB_B8 | B FB_ALE | | B EMMC_D6 |
+| 37 | B GPIOB_B9 | B FB_OE | B FB_TBST | B EMMC_D7 |
+| 38 | B GPIOB_B10 | B FB_RW | | |
+
+We also check i\_class/interfaces.txt to see if the single requested emmc
+interface is there:
+
+ gpiob 1
+ eint 1
+ mqspi 1
+ emmc 1 <--
+ uart 3
+
+Also we examine the i\_class/emmc.txt file to check that it has the right
+types of pin definitions:
+
+ cmd out
+ clk out
+ d0 inout bus
+ d1 inout bus
+ d2 inout bus
+ d3 inout bus
+ d4 inout bus
+ d5 inout bus
+ d6 inout bus
+ d7 inout bus
+
+and we check the i\_class/pinmap.txt tab-separated file to see if it
+contains the entries corresponding to the markdown table:
+
+ 24 A 4 gpioa_a24 mspi1_ck jtag_tms mmc0_d0
+ 25 A 4 gpioa_a25 mspi1_nss jtag_tdi mmc0_d1
+ 26 A 4 gpioa_a26 mspi1_io0 jtag_tdo mmc0_d2
+ 27 A 4 gpioa_a27 mspi1_io1 jtag_tck mmc0_d3
+ 28 B 4 gpiob_b0 fb_ad2 emmc_cmd
+ 29 B 4 gpiob_b1 fb_ad3 emmc_clk
+ 30 B 4 gpiob_b2 fb_ad4 emmc_d0
+ 31 B 4 gpiob_b3 fb_ad5 emmc_d1
+ 32 B 4 gpiob_b4 fb_ad6 emmc_d2
+ 33 B 4 gpiob_b5 fb_ad7 emmc_d3
+ 34 B 4 gpiob_b6 fb_cs0 emmc_d4
+ 35 B 4 gpiob_b7 fb_cs1 emmc_d5
+ 36 B 4 gpiob_b8 fb_ale emmc_d6
+ 37 B 4 gpiob_b9 fb_oe fb_tbst emmc_d7
+
+This concludes this section as the purpose of the spec-generation side,
+to create documentation and TSV files for the second phase, has been
+fulfilled. Note that we did *not* declare in PinSpec that this
+peripheral is to be added onto the fastbus, as by default peripherals
+are added to a single AXI4-Lite interface.
+
+## Adding the code auto-generators.
+
+The next phase begins with adding class support to auto-generate the pinmux
+code. Starting with the following command:
+
+ $ python src/pinmux_generator.py -o i_class
+
+The first thing to do is look at i\_class/bsv\_src/pinmux.bsv, and search
+for both PeripheralSideMMC and PeripheralSideEMMC. PeripheralSideMMC is
+very short and compact:
+
+ // interface declaration between MMC and pinmux
+ (*always_ready,always_enabled*)
+ interface PeripheralSideMMC;
+ interface Put#(Bit#(1)) cmd;
+ interface Put#(Bit#(1)) clk;
+ interface Put#(Bit#(4)) out;
+ interface Put#(Bit#(4)) out_en;
+ interface Get#(Bit#(4)) in;
+ endinterface
+
+whereas PeripheralSideEMMC is a mess:
+
+ interface PeripheralSideEMMC;
+ interface Put#(Bit#(1)) cmd;
+ interface Put#(Bit#(1)) clk;
+ interface Put#(Bit#(1)) d0_out;
+ interface Put#(Bit#(1)) d0_outen;
+ interface Get#(Bit#(1)) d0_in;
+ interface Put#(Bit#(1)) d1_out;
+ interface Put#(Bit#(1)) d1_outen;
+ interface Get#(Bit#(1)) d1_in;
+ interface Put#(Bit#(1)) d2_out;
+ interface Put#(Bit#(1)) d2_outen;
+ interface Get#(Bit#(1)) d2_in;
+ ...
+ ...
+ endinterface
+
+To correct this, we need to create an InterfaceEMMC class in
+src/bsv/interface\_decl.py that generates the right code. However on
+close inspection, given that the format needed is identical (except for
+the number of data lines), we can probably get away with using *exactly*
+the same class:
+
+ class Interfaces(InterfacesBase, PeripheralInterfaces):
+
+ def __init__(self, pth=None):
+ InterfacesBase.__init__(self, Interface, pth,
+ {'gpio': InterfaceGPIO,
+ ...
+ ...
+ 'mmc': InterfaceSD,
+ 'emmc': InterfaceSD, <--
+ 'fb': InterfaceFlexBus,
+ ...
+
+and after re-running the command the output looks like this:
+
+ interface PeripheralSideEMMC;
+ interface Put#(Bit#(1)) cmd;
+ interface Put#(Bit#(1)) clk;
+ interface Put#(Bit#(8)) out;
+ interface Put#(Bit#(8)) out_en;
+ interface Get#(Bit#(8)) in;
+ endinterface
+
+Success! The class InterfaceSD appears to be sufficiently generic that
+it could understand that it had been passed 8-pins worth of data with
+exactly the same names, rather than 4. This is encouraging in the sense
+that re-using the SD/MMC BSV generation code should also be as easy.
# Conclusion
projects / pinmux.git / commitdiff