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used with Terasic's DE-4 and other similar FPGA boards. This display is 800x480 and includes a capacitive touch screen, multi-touch gesture recognition, etc. This device driver depends on a Cambridge- provided IP core that allows the MTL device to be hooked up to the Altera Avalon SoC bus, and also provides a VGA-like text frame buffer. Although it is compiled as a single device driver, it actually implements a number of different device nodes exporting various aspects of this multi-function device to userspace: - Simple memory-mapped driver for the MTL 24-bit pixel frame buffer. - Simple memory-mapped driver for the MTL control register set. - Simple memory-mapped driver for the MTL text frame buffer. - syscons attachment for the MTL text frame buffer. This driver attaches directly to Nexus as is common for SoC device drivers, and for the time being is considered BERI-specific, although in principle it might be used with other hard and soft cores on Altera FPGAs. Control registers, including touchscreen input, are simply memory mapped; in the future it would be desirable to hook up a more conventional device node that can stream events, support kqueue(2)/ poll(2)/select(2), etc. This is the first use of syscons on MIPS, as far as I can tell, and there are some loose ends, such as an inability to use the hardware cursor. More fundamentally, it appears that syscons(4) assumes that either a host is PC-like (i386, amd64) *or* it must be using a graphical frame buffer. While the MTL supports a graphical frame buffer, using the text frame buffer is preferable for console use. Fixing this issue in syscons(4) requires non-trivial changes, as the text frame buffer support assumes that direct memory access can be done to the text frame buffer without using bus accessor methods, which is not the case on MIPS. As a workaround for this, we instead double-buffer and pretend to be a graphical frame buffer exposing text accessor methods, leading to some quirks in syscons behaviour. Sponsored by: DARPA, AFRL
133 lines
4.1 KiB
Groff
133 lines
4.1 KiB
Groff
.\"-
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.\" Copyright (c) 2012 Robert N. M. Watson
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.\" All rights reserved.
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.\"
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.\" This software was developed by SRI International and the University of
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.\" Cambridge Computer Laboratory under DARPA/AFRL contract (FA8750-10-C-0237)
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.\" ("CTSRD"), as part of the DARPA CRASH research programme.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd August 18, 2012
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.Dt TERASIC_MTL 4
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.Os
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.Sh NAME
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.Nm terasic_mtl
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.Nd driver for the Terasic/Cambridge Multi-Touch LCD device
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.Sh SYNOPSIS
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.Cd "device terasic_mtl"
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.Pp
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In
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.Pa /boot/device.hints :
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.Cd hint.terasic_mtl.0.at="nexus0"
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.Cd hint.terasic_mtl.0.reg_maddr=0x70400000
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.Cd hint.terasic_mtl.0.reg_msize=0x1000
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.Cd hint.terasic_mtl.0.pixel_maddr=0x70000000
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.Cd hint.terasic_mtl.0.pixel_msize=0x177000
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.Cd hint.terasic_mtl.0.text_maddr=0x70177000
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.Cd hint.terasic_mtl.0.text_msize=0x2000
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.Sh DESCRIPTION
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The
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.Nm
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device driver provides support for the Terasic Multi-Touch LCD combined as
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controlled by a University of Cambridge's IP Core.
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Three device nodes are instantiated, representing various services supported
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by the device:
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.Bl -tag -width terasic_pixelX
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.It terasic_regX
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Memory-mapped register interface, including touch screen input.
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.It terasic_pixelX
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Memory-mapped pixel-oriented frame buffer.
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.It terasic_textX
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Memory-mapped text-oriented frame buffer.
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.El
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.Pp
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.Nm
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devices are also attached to the
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.Xr syscons 4
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framework, which implements a VT-compatible terminal connected to the
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.Xr tty 4
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framework.
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.Li ttyvX
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device nodes may be added to
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.Xr ttys 5
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in order to launch
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.Xr login 1
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sessions at boot.
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.Pp
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Register, text, and pixel devices may be accessed using
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.Xr read 2
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and
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.Xr write 2
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system calls, and also memory mapped using
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.Xr mmap 2 .
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.Sh SEE ALSO
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.Xr login 1 ,
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.Xr ioctl 2 ,
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.Xr mmap 2 ,
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.Xr poll 2 ,
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.Xr read 2 ,
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.Xr write 2 ,
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.Xr syscons 4 ,
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.Xr tty 4 ,
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.Xr ttys 5
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.Sh HISTORY
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The
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.Nm
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device driver first appeared in
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.Fx 10.0 .
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.Sh AUTHORS
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The
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.Nm
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device driver and this manual page were
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developed by SRI International and the University of Cambridge Computer
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Laboratory under DARPA/AFRL contract
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.Pq FA8750-10-C-0237
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.Pq Do CTSRD Dc ,
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as part of the DARPA CRASH research programme.
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This device driver was written by
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.An Robert N. M. Watson .
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.Sh BUGS
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.Nm
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The
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.Xr syscons 4
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attachment does not support the hardware cursor feature.
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.Pp
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A more structured interface to control registers using the
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.Xr ioctl 2
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system call, would sometimes be preferable to memory mapping.
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For touch screen input, it would be highly desirable to offer a streaming
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interface whose events can be managed using
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.Xr poll 2
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and related system calls, with the kernel performing polling rather than the
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userspace application.
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.Pp
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.Nm
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supports only a
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.Li nexus
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bus attachment, which is appropriate for system-on-chip busses such as
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Altera's Avalon bus.
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If the IP core is configured off of another bus type, then additional bus
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attachments will be required.
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