130 lines
4.1 KiB
C
130 lines
4.1 KiB
C
/*
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* Copyright (c) 2013, Peter Rutenbar <pruten@gmail.com>
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* All rights reserved.
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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 are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <assert.h>
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#include "shoebill.h"
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const char *latch_names[8] = {
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"phase0", "phase1", "phase2", "phase3",
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"motor", "drive", "L6", "L7"
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};
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const char *reg_names[8] = {
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"ones", "read-data", "status", "status",
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"handshake", "handshake", "mode", "write-data"
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};
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uint8_t iwm_dma_read()
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{
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const uint8_t latch_addr = (shoe.physical_addr >> 10) & 0x7;
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const uint8_t latch_val = (shoe.physical_addr >> 9) & 1;
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uint8_t result;
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if (latch_val)
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shoe.iwm.latch |= (1 << latch_addr);
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else
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shoe.iwm.latch &= (~(1 << latch_addr));
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// reg = {q7, q6, motor}
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const uint8_t reg = ((shoe.iwm.latch >> 5) & 6) |
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((shoe.iwm.latch >> 4) & 1);
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printf("iwm_dma_read: %s %s (reg = %u%u%u '%s' ",
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latch_val ? "setting" : "clearing",
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latch_names[latch_addr],
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(reg>>2), (reg>>1)&1, reg&1, reg_names[reg]);
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// Allegedly, register reads can only occur when latch_val==0
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if (latch_val) {
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result = 0;
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goto done;
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}
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switch (reg) {
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case 0: // read all ones
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result = 0xff;
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break;
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case 1: // read data register
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result = shoe.iwm.data;
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break;
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case 2:
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case 3: // Read status register
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// High 3 bits are mode register, low 5 are status
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result = (shoe.iwm.status & 0b10100000);
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result |= (shoe.iwm.mode & 0b11111);
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break;
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case 4:
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case 5: // Read "write-handshake" register
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result = (shoe.iwm.handshake | 0b00111111); // low 6 bits all 1's
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break;
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default:
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result = 0;
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break;
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}
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done:
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printf("result=0x%02x)\n", result);
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return result;
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}
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void iwm_dma_write()
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{
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const uint8_t latch_addr = (shoe.physical_addr >> 10) & 0x7;
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const uint8_t latch_val = (shoe.physical_addr >> 9) & 1;
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uint8_t data = shoe.physical_dat;
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if (latch_val)
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shoe.iwm.latch |= (1 << latch_addr);
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else
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shoe.iwm.latch &= (~(1 << latch_addr));
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// reg = {q7, q6, motor}
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const uint8_t reg = ((shoe.iwm.latch >> 5) & 6) |
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((shoe.iwm.latch >> 4) & 1);
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printf("iwm_dma_write: %s %s (reg = %u%u%u '%s' val 0x%02x)\n",
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latch_val ? "setting" : "clearing",
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latch_names[latch_addr],
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(reg>>2), (reg>>1)&1, reg&1, reg_names[reg],
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data);
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// Allegedly, register writes can only occur when latch_val==1
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if (!latch_val) {
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return ;
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}
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switch (reg) {
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case 6: // Write mode
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shoe.iwm.mode = data & 0b01111111;
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break;
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case 7: // Write data
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shoe.iwm.data = data;
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break;
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}
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} |