xref: /freebsd/share/man/man4/man4.arm/devcfg.4 (revision 5ca8e32633c4ffbbcd6762e5888b6a4ba0708c6c)
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25.Dd February 28, 2013
26.Dt DEVCFG 4
27.Os
28.Sh NAME
29.Nm devcfg
30.Nd Zynq PL device config interface
31.Sh SYNOPSIS
32.Cd device devcfg
33.Sh DESCRIPTION
34The special file
35.Pa /dev/devcfg
36can be used to configure the PL (FPGA) section of the Xilinx Zynq-7000.
37.Pp
38On the first write to the character device at file offset 0, the
39.Nm
40driver
41asserts the top-level PL reset signals, disables the PS-PL level shifters,
42and clears the PL configuration.
43Write data is sent to the PCAP (processor configuration access port).
44When the PL asserts the DONE signal, the devcfg driver will enable the level
45shifters and release the top-level PL reset signals.
46.Pp
47The PL (FPGA) can be configured by writing the bitstream to the character
48device like this:
49.Bd -literal -offset indent
50cat design.bit.bin > /dev/devcfg
51.Ed
52.Pp
53The file should not be confused with the .bit file output by the FPGA
54design tools.
55It is the binary form of the configuration bitstream.
56The Xilinx
57.Ic promgen
58tool can do the conversion:
59.Bd -literal -offset indent
60promgen -b -w -p bin -data_width 32 -u 0 design.bit -o design.bit.bin
61.Ed
62.Sh SYSCTL VARIABLES
63The
64.Nm
65driver provides the following
66.Xr sysctl 8
67variables:
68.Bl -tag -width 4n
69.It Va hw.fpga.pl_done
70.Pp
71This variable always reflects the status of the PL's DONE signal.
72A 1 means the PL section has been properly programmed.
73.It Va hw.fpga.en_level_shifters
74.Pp
75This variable controls if the PS-PL level shifters are enabled after the
76PL section has been reconfigured.
77This variable is 1 by default but setting it to 0 allows the PL section to be
78programmed with configurations that do not interface to the PS section of the
79part.
80Changing this value has no effect on the level shifters until the next device
81reconfiguration.
82.El
83.Sh FILES
84.Bl -tag -width 12n
85.It Pa /dev/devcfg
86Character device for the
87.Nm
88driver.
89.El
90.Sh SEE ALSO
91Zynq-7000 SoC Technical Reference Manual (Xilinx doc UG585)
92.Sh AUTHORS
93.An Thomas Skibo
94