xref: /freebsd/share/man/man4/man4.arm/devcfg.4 (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
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25.\" $FreeBSD$
26.\"
27.Dd February 28, 2013
28.Dt DEVCFG 4
29.Os
30.Sh NAME
31.Nm devcfg
32.Nd Zynq PL device config interface
33.Sh SYNOPSIS
34.Cd device devcfg
35.Sh DESCRIPTION
36The special file
37.Pa /dev/devcfg
38can be used to configure the PL (FPGA) section of the Xilinx Zynq-7000.
39.Pp
40On the first write to the character device at file offset 0, the
41.Nm
42driver
43asserts the top-level PL reset signals, disables the PS-PL level shifters,
44and clears the PL configuration.
45Write data is sent to the PCAP (processor configuration access port).
46When the PL asserts the DONE signal, the devcfg driver will enable the level
47shifters and release the top-level PL reset signals.
48.Pp
49The PL (FPGA) can be configured by writing the bitstream to the character
50device like this:
51.Bd -literal -offset indent
52cat design.bit.bin > /dev/devcfg
53.Ed
54.Pp
55The file should not be confused with the .bit file output by the FPGA
56design tools.
57It is the binary form of the configuration bitstream.
58The Xilinx
59.Ic promgen
60tool can do the conversion:
61.Bd -literal -offset indent
62promgen -b -w -p bin -data_width 32 -u 0 design.bit -o design.bit.bin
63.Ed
64.Sh SYSCTL VARIABLES
65The
66.Nm
67driver provides the following
68.Xr sysctl 8
69variables:
70.Bl -tag -width 4n
71.It Va hw.fpga.pl_done
72.Pp
73This variable always reflects the status of the PL's DONE signal.
74A 1 means the PL section has been properly programmed.
75.It Va hw.fpga.en_level_shifters
76.Pp
77This variable controls if the PS-PL level shifters are enabled after the
78PL section has been reconfigured.
79This variable is 1 by default but setting it to 0 allows the PL section to be
80programmed with configurations that do not interface to the PS section of the
81part.
82Changing this value has no effect on the level shifters until the next device
83reconfiguration.
84.El
85.Sh FILES
86.Bl -tag -width 12n
87.It Pa /dev/devcfg
88Character device for the
89.Nm
90driver.
91.El
92.Sh SEE ALSO
93Zynq-7000 SoC Technical Reference Manual (Xilinx doc UG585)
94.Sh AUTHORS
95.An Thomas Skibo
96