101 lines
2.6 KiB
C++
101 lines
2.6 KiB
C++
/*
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DingusPPC - The Experimental PowerPC Macintosh emulator
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Copyright (C) 2018-20 divingkatae and maximum
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(theweirdo) spatium
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(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
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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 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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/** @file Descriptor-based direct memory access emulation.
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Official documentation can be found in the fifth chapter of the book
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"Macintosh Technology in the Common Hardware Reference Platform"
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by Apple Computer, Inc.
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*/
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#ifndef DB_DMA_H
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#define DB_DMA_H
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#include <cinttypes>
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/** DBDMA Channel registers offsets */
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enum DMAReg : uint32_t {
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CH_CTRL = 0,
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CH_STAT = 4,
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CMD_PTR_LO = 12,
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};
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/** Channel Status bits (DBDMA spec, 5.5.3) */
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enum {
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CH_STAT_ACTIVE = 0x400,
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CH_STAT_DEAD = 0x800,
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CH_STAT_WAKE = 0x1000,
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CH_STAT_FLUSH = 0x2000,
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CH_STAT_PAUSE = 0x4000,
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CH_STAT_RUN = 0x8000
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};
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/** DBDMA command (DBDMA spec, 5.6.1) - all fields are little-endian! */
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typedef struct DMACmd {
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uint16_t req_count;
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uint8_t cmd_bits;
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uint8_t cmd_key;
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uint32_t address;
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uint32_t cmd_arg;
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uint16_t res_count;
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uint16_t xfer_stat;
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} DMACmd;
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class DMACallback {
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public:
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virtual void dma_start(void) = 0;
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virtual void dma_end(void) = 0;
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virtual void dma_push(uint8_t* buf, int size) = 0;
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virtual void dma_pull(uint8_t* buf, int size) = 0;
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};
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class DMAChannel {
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public:
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DMAChannel(DMACallback* cb) {
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this->dma_cb = cb;
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};
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~DMAChannel() = default;
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uint32_t reg_read(uint32_t offset, int size);
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void reg_write(uint32_t offset, uint32_t value, int size);
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int get_data(uint32_t req_len, uint32_t* avail_len, uint8_t** p_data);
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protected:
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void get_next_cmd(uint32_t cmd_addr, DMACmd* p_cmd);
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uint8_t interpret_cmd(void);
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void start(void);
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void resume(void);
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void abort(void);
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void pause(void);
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private:
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DMACallback* dma_cb = 0;
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uint16_t ch_stat = 0;
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uint32_t cmd_ptr = 0;
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uint32_t queue_len;
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uint8_t* queue_data;
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};
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#endif /* DB_DMA_H */
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