xref: /freebsd/share/man/man4/man4.arm/devcfg.4 (revision 9c5e50716bfc177737d9eb0ad86d4e4b72a73b81)
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25.\" $FreeBSD$
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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 devcfg driver
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.Pa 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 devcfg driver provides the following
64.Xr sysctl 8
65variables:
66.Bl -tag -width 12
67.It Va hw.fpga.pl_done
68.Pp
69This variable always reflects the status of the PL's DONE signal.
70A 1 means the PL section has been properly programmed.
71.It Va hw.fpga.en_level_shifters
72.Pp
73This variable controls if the PS-PL level shifters are enabled after the
74PL section has been reconfigured.
75This variable is 1 by default but setting it to 0 allows the PL section to be
76programmed with configurations that don't interface to the PS section of the
77part.
78Changing this value has no effect on the level shifters until the next device
79reconfiguration.
80.Sh FILES
81/dev/devcfg Character device for
82.Nm
83driver.
84.Sh AUTHORS
85Thomas Skibo
86.Sh SEE ALSO
87Zynq-7000 SoC Technical Reference Manual (Xilinx doc UG585)
88