/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-23 divingkatae and maximum
(theweirdo) spatium
(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
/** @file Descriptor-based direct memory access emulation.
Official documentation can be found in the fifth chapter of the book
"Macintosh Technology in the Common Hardware Reference Platform"
by Apple Computer, Inc.
*/
#ifndef DB_DMA_H
#define DB_DMA_H
#include
#include
#include
/** DBDMA Channel registers offsets */
enum DMAReg : uint32_t {
CH_CTRL = 0,
CH_STAT = 4,
CMD_PTR_LO = 12,
INT_SELECT = 16,
BRANCH_SELECT = 20,
};
/** Channel Status bits (DBDMA spec, 5.5.3) */
enum : uint16_t {
CH_STAT_ACTIVE = 0x400,
CH_STAT_DEAD = 0x800,
CH_STAT_WAKE = 0x1000,
CH_STAT_FLUSH = 0x2000,
CH_STAT_PAUSE = 0x4000,
CH_STAT_RUN = 0x8000
};
/** DBDMA command (DBDMA spec, 5.6.1) - all fields are little-endian! */
typedef struct DMACmd {
uint16_t req_count;
uint8_t cmd_bits;
uint8_t cmd_key;
uint32_t address;
uint32_t cmd_arg;
uint16_t res_count;
uint16_t xfer_stat;
} DMACmd;
namespace DBDMA_Cmd {
enum : uint8_t {
OUTPUT_MORE = 0,
OUTPUT_LAST = 1,
INPUT_MORE = 2,
INPUT_LAST = 3,
STORE_QUAD = 4,
LOAD_QUAD = 5,
NOP = 6,
STOP = 7
};
};
typedef std::function DbdmaCallback;
class DMAChannel : public DmaBidirChannel {
public:
DMAChannel() = default;
~DMAChannel() = default;
void set_callbacks(DbdmaCallback start_cb, DbdmaCallback stop_cb);
uint32_t reg_read(uint32_t offset, int size);
void reg_write(uint32_t offset, uint32_t value, int size);
bool is_active();
DmaPullResult pull_data(uint32_t req_len, uint32_t *avail_len, uint8_t **p_data);
int push_data(const char* src_ptr, int len);
protected:
void fetch_cmd(uint32_t cmd_addr, DMACmd* p_cmd);
uint8_t interpret_cmd(void);
void start(void);
void resume(void);
void abort(void);
void pause(void);
private:
std::function start_cb = nullptr; // DMA channel start callback
std::function stop_cb = nullptr; // DMA channel stop callback
uint16_t ch_stat = 0;
uint32_t cmd_ptr = 0;
uint32_t queue_len = 0;
uint8_t* queue_data = 0;
uint32_t branch_select = 0;
bool cmd_in_progress = false;
uint8_t cur_cmd;
};
#endif /* DB_DMA_H */