mirror of
git://projects.qi-hardware.com/ben-blinkenlights.git
synced 2024-11-16 21:32:49 +02:00
467 lines
8.2 KiB
C
467 lines
8.2 KiB
C
/*
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* ubb-vga.c - Output video on UBB with more or less VGA timing
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*
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* Written 2011 by Werner Almesberger
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* Copyright 2011 Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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/*
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* WARNING: this program does very nasty things to the Ben and it doesn't
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* like company. In particular, it resents:
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*
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* - the MMC driver - disable it with
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* echo jz4740-mmc.0 >/sys/bus/platform/drivers/jz4740-mmc/unbind
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* - the AT86RF230/1 kernel driver - use a kernel that doesn't have it
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* - anything that accesses the screen - kill GUI, X server, etc.
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* - the screen blanker - either disable it or make sure the screen stays
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* dark, e.g., with
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* echo 1 >/sys/devices/platform/jz4740-fb/graphics/fb0/blank
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* - probably a fair number of other daemons and things as well - best to
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* kill them all.
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*/
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <fcntl.h>
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#include <sys/mman.h>
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static uint8_t thres = 63;
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/* ----- I/O pin assignment ------------------------------------------------ */
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#define DAT0 (1 << 10)
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#define DAT1 (1 << 11)
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#define DAT2 (1 << 12)
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#define DAT3 (1 << 13)
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#define CMD (1 << 8)
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#define CLK (1 << 9)
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#define R DAT3
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#define G DAT0
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#define B DAT1
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#define HSYNC CMD
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#define VSYNC CLK
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/* ----- Ben hardware ------------------------------------------------------ */
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#define TIMER 7
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#define PAGE_SIZE 4096
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#define SOC_BASE 0x10000000
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static volatile uint32_t *icmr, *icmsr, *icmcr;
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static uint32_t old_icmr;
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static volatile uint32_t *clkgr;
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static uint32_t old_clkgr;
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static volatile uint32_t *pdpin, *pddats, *pddatc;
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static volatile uint32_t *pddirs, *pddirc;
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static volatile uint32_t *pdfuns, *pdfunc;
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static volatile uint32_t *tssr, *tscr;
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static volatile uint32_t *tesr, *tecr;
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static volatile uint32_t *tcsr, *tdfr, *tcnt;
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static void disable_interrupts(void)
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{
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/*
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* @@@ Race condition alert ! If we get interrupted/preempted between
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* reading ICMR and masking all interrupts, and the code that runs
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* between these two operations changes ICMR, then we may set an
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* incorrect mask when restoring interrupts, which may hang the system.
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*/
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old_icmr = *icmr;
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*icmsr = 0xffffffff;
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}
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static void enable_interrupts(void)
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{
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*icmcr = ~old_icmr;
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}
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/*
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* @@@ Disabling the LCD clock will hang operations that depend on the LCD
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* subsystem to advance. This includes the screen saver.
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*/
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static void disable_lcd(void)
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{
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old_clkgr = *clkgr;
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*clkgr = old_clkgr | 1 << 10;
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}
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static void enable_lcd(void)
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{
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*clkgr = old_clkgr;
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}
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static void get_timer(void)
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{
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*tscr = 1 << TIMER; /* enable clock */
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*tcsr = 1; /* count at PCLK/1 */
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*tdfr = 0xffff; /* count to 0xffff */
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*tesr = 1 << TIMER;
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}
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static void release_timer(void)
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{
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*tecr = 1 << TIMER;
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*tssr = 1 << TIMER;
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}
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static void *map(off_t addr, size_t size)
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{
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int fd;
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void *mem;
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fd = open("/dev/mem", O_RDWR | O_SYNC);
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if (fd < 0) {
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perror("/dev/mem");
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exit(1);
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}
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mem = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, addr);
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if (mem == MAP_FAILED) {
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perror("mmap");
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exit(1);
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}
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return mem;
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}
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static void ben_setup(void)
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{
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volatile void *base;
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base = map(SOC_BASE, PAGE_SIZE*3*16);
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icmr = base+0x1004;
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icmsr = base+0x1008;
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icmcr = base+0x100c;
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clkgr = base+0x20;
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pdpin = base+0x10300;
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pddats = base+0x10314;
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pddatc = base+0x10318;
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pdfuns = base+0x10344;
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pdfunc = base+0x10348;
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pddirs = base+0x10364;
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pddirc = base+0x10368;
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tssr = base+0x202c;
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tscr = base+0x203c;
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tesr = base+0x2014;
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tecr = base+0x2018;
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tcsr = base+0x204c+0x10*TIMER;
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tdfr = base+0x2040+0x10*TIMER;
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tcnt = base+0x2048+0x10*TIMER;
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/*
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* Ironically, switching the LCD clock on and off many times only
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* increases the risk of a hang. Therefore, we leave stop it during
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* all the measurements and only enable it again at the end.
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*/
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disable_lcd();
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get_timer();
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}
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static void cleanup(void)
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{
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release_timer();
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enable_lcd();
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}
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/* ----- Prefetch and delay logic ------------------------------------------ */
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#define BURST 32 /* bytes */
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static inline void prefetch(const uint8_t *prefetch, int words)
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{
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volatile const uint8_t *p = prefetch;
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while (p != prefetch+words) {
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(void) *p;
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p += BURST;
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}
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}
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#define US(us) ((uint16_t) ((us)*112))
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static void until(uint16_t cycles)
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{
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while ((*tcnt & 0xffff) < cycles);
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}
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/* ----- Frame buffer output ----------------------------------------------- */
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static int line_pairs = 160; /* set/clear pairs */
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static int line_cycles = US(36); /* nominally 31.77 us, but we're too slow */
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void setup(void)
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{
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mlockall(MCL_CURRENT | MCL_FUTURE);
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ben_setup();
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*pdfunc = R | G | B | HSYNC | VSYNC;
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*pddirs = R | G | B | HSYNC | VSYNC;
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}
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static void line(const uint8_t *line, const uint8_t *fetch)
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{
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const uint8_t *p = line;
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/* HSYNC */
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*tcnt = 0;
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*pddatc = HSYNC;
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prefetch(fetch, line_pairs);
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until(US(3.77));
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*pddats = HSYNC;
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/* Front porch */
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until(US(3.77+1.79));
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while (p != line+2*line_pairs) {
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*pddats = *p++ << 8;
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*pddatc = *p++ << 8;
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}
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/* Back porch */
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until(line_cycles);
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}
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static void hdelay(int cycles)
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{
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while (cycles--) {
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*tcnt = 0;
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*pddatc = HSYNC;
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until(US(3.77));
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*pddats = HSYNC;
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until(line_cycles);
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}
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}
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static void frame(const uint8_t *f)
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{
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const uint8_t *p;
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/* VSYNC */
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*pddatc = VSYNC;
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hdelay(2);
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*pddats = VSYNC;
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/* Front porch */
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*tcnt = 0;
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*pddatc = HSYNC;
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until(US(3.77));
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*pddats = HSYNC;
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prefetch(f, line_pairs);
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until(line_cycles);
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hdelay(31);
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for (p = f; p != f+240*2*line_pairs; p += 2*line_pairs) {
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line(p, p+line_pairs);
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line(p, p+2*line_pairs);
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}
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/* Back porch */
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hdelay(14);
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}
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/* ----- Frame buffer image generation ------------------------------------- */
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static uint32_t pick(int set, int bit, uint32_t val)
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{
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return set == bit ? val >> 8 : 0;
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}
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static uint32_t pattern(int set, int r, int g, int b)
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{
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return pick(set, r, R) | pick(set, g, G) | pick(set, b, B);
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}
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static void tricolor(uint32_t *f)
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{
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int pairs = 2*line_pairs*240;
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int i;
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for (i = 0; i != pairs/3; i++) {
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f[i & ~1] = R;
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f[i | 1] = G | B;
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}
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for (; i != pairs*2/3; i++) {
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f[i & ~1] = G;
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f[i | 1] = R | B;
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}
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for (; i != pairs; i++) {
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f[i & ~1] = B;
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f[i | 1] = R | G;
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}
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}
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static void grid(uint8_t *f)
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{
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static uint32_t col[8] = {
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R | G | B,
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R,
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R | G,
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G,
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G | B,
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B,
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R | B,
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R | G | B,
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};
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int i, x, y;
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for (i = 0; i != 8; i++) {
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x = i*line_pairs/4+line_pairs/8;
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for (y = 0; y != 240; y++) {
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uint8_t *p = f+y*2*line_pairs+x;
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p[0] = p[1] = col[i] >> 8;
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}
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}
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}
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static void grab(uint8_t *f, int single)
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{
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uint32_t *fb = map(0x01d00000, 4*320*240);
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int x, y;
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uint32_t pix;
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uint8_t r, g, b;
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for (y = 0; y != 240; y++)
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for (x = 0; x != 320; x++) {
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pix = *fb++;
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r = pix >> 16;
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g = pix >> 8;
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b = pix;
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if (single)
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*f++ = pattern(!(x & 1),
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r >= thres, g >= thres, b >= thres);
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else {
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*f++ = pattern(1,
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r >= thres, g >= thres, b >= thres);
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*f++ = pattern(0,
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r >= thres, g >= thres, b >= thres);
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}
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}
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}
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/* ----- Command-line parsing and main loop -------------------------------- */
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static void session(int frames, int single)
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{
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uint8_t f[2*line_pairs*(240+1)];
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int i;
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memset(f, 0, sizeof(f));
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grab(f, single);
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// grid(f);
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disable_interrupts();
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for (i = 0; i != frames; i++)
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frame(f);
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enable_interrupts();
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}
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static void usage(const char *name)
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{
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fprintf(stderr,
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"usage: %s frames -d [threshold]\n\n"
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" frames number of frames to display\n"
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" threshold channel on/off threshold\n\n"
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" -d double the number of set/clear pairs\n"
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, name);
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exit(1);
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}
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int main(int argc, char *const *argv)
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{
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int frames;
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int single = 1;
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int c;
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while ((c = getopt(argc, argv, "d")) != EOF)
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switch (c) {
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case 'd':
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single = 0;
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line_pairs = 320;
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line_cycles = US(36+26);
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break;
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default:
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usage(*argv);
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}
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switch (argc-optind) {
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case 2:
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thres = atoi(argv[optind+1]);
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/* fall through */
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case 1:
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frames = atoi(argv[optind]);
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break;
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default:
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usage(*argv);
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}
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setup();
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session(frames, single);
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cleanup();
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return 0;
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}
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