Add terasic_mtl(4), a device driver for the Terasic Multi-Touch LCD,

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

3 files changed, 15 insertions, 2 deletions

diff --git a/sys/mips/conf/BERI_DE4.hints b/sys/mips/conf/BERI_DE4.hints
index 4ffe6c2..b2a0e0a 100644
--- a/sys/mips/conf/BERI_DE4.hints
+++ b/sys/mips/conf/BERI_DE4.hints
@@ -25,6 +25,17 @@ hint.altera_sdcardc.0.maddr=0x7f008000
 hint.altera_sdcardc.0.msize=0x400
 
 #
+# Terasic Multi-touch LCD (MTL), an optional feature in DE-4 configurations.
+#
+hint.terasic_mtl.0.at="nexus0"
+hint.terasic_mtl.0.reg_maddr=0x70400000
+hint.terasic_mtl.0.reg_msize=0x1000
+hint.terasic_mtl.0.pixel_maddr=0x70000000
+hint.terasic_mtl.0.pixel_msize=0x177000
+hint.terasic_mtl.0.text_maddr=0x70177000
+hint.terasic_mtl.0.text_msize=0x2000
+
+#
 # BERI Hardware Version ROM
 #
 hint.altera_avgen.0.at="nexus0"
diff --git a/sys/mips/conf/BERI_DE4_MDROOT b/sys/mips/conf/BERI_DE4_MDROOT
index 658c925..75d9b4e 100644
--- a/sys/mips/conf/BERI_DE4_MDROOT
+++ b/sys/mips/conf/BERI_DE4_MDROOT
@@ -24,6 +24,7 @@ options 	ROOTDEVNAME=\"ufs:md0\"
 device		altera_avgen
 device		altera_jtag_uart
 device		altera_sdcard
+device		terasic_mtl
 
 device		isf
-#device		sc
+device		sc
diff --git a/sys/mips/conf/BERI_DE4_SDROOT b/sys/mips/conf/BERI_DE4_SDROOT
index b41e6ff..a638e46 100644
--- a/sys/mips/conf/BERI_DE4_SDROOT
+++ b/sys/mips/conf/BERI_DE4_SDROOT
@@ -17,6 +17,7 @@ options 	ROOTDEVNAME=\"ufs:altera_sdcard0\"
 device		altera_avgen
 device		altera_jtag_uart
 device		altera_sdcard
+device		terasic_mtl
 
 device		isf
-#device		sc
+device		sc