src/ide/AbstractIDEDevice.hh at main · doomsdayone/openmsx

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#ifndef ABSTRACTIDEDEVICE_HH
#define ABSTRACTIDEDEVICE_HH

#include "IDEDevice.hh"

#include "serialize_meta.hh"

#include "AlignedBuffer.hh"

namespace openmsx {

class MSXMotherBoard;

class AbstractIDEDevice : public IDEDevice
{
public:
	void reset(EmuTime time) override;

	[[nodiscard]] uint16_t readData(EmuTime time) override;
	[[nodiscard]] uint8_t readReg(uint4_t reg, EmuTime time) override;

	void writeData(uint16_t value, EmuTime time) override;
	void writeReg(uint4_t reg, uint8_t value, EmuTime time) override;

	template<typename Archive>
	void serialize(Archive& ar, unsigned version);

protected:
	// Bit flags for the status register:
	static constexpr uint8_t DRDY = 0x40;
	static constexpr uint8_t DSC = 0x10;
	static constexpr uint8_t DRQ = 0x08;
	static constexpr uint8_t ERR = 0x01;

	// Bit flags for the error register:
	static constexpr uint8_t UNC = 0x40;
	static constexpr uint8_t IDNF = 0x10;
	static constexpr uint8_t ABORT = 0x04;

	explicit AbstractIDEDevice(MSXMotherBoard& motherBoard);
	~AbstractIDEDevice() override = default;

	/** Is this device a packet (ATAPI) device?
	  * @return True iff this device supports the packet commands.
	  */
	[[nodiscard]] virtual bool isPacketDevice() = 0;

	/** Gets the device name to insert as "model number" into the identify
	  * block.
	  * @return An ASCII string, up to 40 characters long.
	  */
	[[nodiscard]] virtual std::string_view getDeviceName() = 0;

	/** Tells a subclass to fill the device specific parts of the identify
	  * block located in the buffer.
	  * The generic part is already written there.
	  * @param buffer Array of 512 bytes.
	  */
	virtual void fillIdentifyBlock(AlignedBuffer& buffer) = 0;

	/** Called when a block of read data should be buffered by the controller:
	  * when the buffer is empty or at the start of the transfer.
	  * @param buffer Pointer to the start of a byte array.
	  * @param count Number of bytes to be filled by this method.
	  *   This number will not exceed the array size nor the transfer length.
	  * @return The number of bytes that was added to the array,
	  *   or 0 if the transfer was aborted (the implementation of this method
	  *   must set the relevant error flags as well).
	  */
	[[nodiscard]] virtual unsigned readBlockStart(AlignedBuffer& buffer, unsigned count) = 0;

	/** Called when a read transfer completes.
	  * The default implementation does nothing.
	  */
	virtual void readEnd();

	/** Called when a block of written data has been buffered by the controller:
	  * when the buffer is full or at the end of the transfer.
	  * @param buffer Pointer to the start of a byte array.
	  * @param count Number of data bytes in the array.
	  */
	virtual void writeBlockComplete(AlignedBuffer& buffer, unsigned count) = 0;

	/** Starts execution of an IDE command.
	  * Override this to implement additional commands and make sure you call
	  * the superclass implementation for all commands that you don't handle.
	  */
	virtual void executeCommand(uint8_t cmd);

	/** Indicates an error: sets error register, error flag, aborts transfers.
	  * @param error Value to be written to the error register.
	  */
	void setError(uint8_t error);

	/** Creates an LBA sector address from the contents of the sectorNumReg,
	  * cylinderLowReg, cylinderHighReg and devHeadReg registers.
	  */
	[[nodiscard]] unsigned getSectorNumber() const;

	/** Gets the number of sectors indicated by the sector count register.
	  */
	[[nodiscard]] unsigned getNumSectors() const;

	/** Writes the interrupt reason register.
	  * This is the same as register as sector count, but serves a different
	  * purpose.
	  */
	void setInterruptReason(uint8_t value);

	/** Reads the byte count limit of a packet transfer in the registers.
	  * The cylinder low/high registers are used for this.
	  */
	[[nodiscard]] unsigned getByteCount() const;

	/** Writes the byte count of a packet transfer in the registers.
	  * The cylinder low/high registers are used for this.
	  */
	void setByteCount(unsigned count);

	/** Writes a 28-bit LBA sector number in the registers.
	  * The cylinder low/high registers are used for this.
	  */
	void setSectorNumber(unsigned lba);

	/** Indicates the start of a read data transfer which uses blocks.
	  * The readBlockStart() method is called at the start of each block.
	  * The first block will be read immediately, so make sure you initialise
	  * all variables needed by readBlockStart() before calling this method.
	  * @param count Total number of bytes to transfer.
	  */
	void startLongReadTransfer(unsigned count);

	/** Indicates the start of a read data transfer where all data fits
	  * into the buffer at once.
	  * @param count Total number of bytes to transfer.
	  * @return Pointer to the start of the buffer.
	  *   The caller should write the data there.
	  *   The relevant part of the buffer contains zeroes.
	  */
	[[nodiscard]] AlignedBuffer& startShortReadTransfer(unsigned count);

	/** Aborts the read transfer in progress.
	  */
	void abortReadTransfer(uint8_t error);

	/** Indicates the start of a write data transfer.
	  * @param count Total number of bytes to transfer.
	  */
	void startWriteTransfer(unsigned count);

	/** Aborts the write transfer in progress.
	  */
	void abortWriteTransfer(uint8_t error);

	[[nodiscard]] uint8_t getFeatureReg() const { return featureReg; }
	void setLBALow (uint8_t value) { sectorNumReg    = value; }
	void setLBAMid (uint8_t value) { cylinderLowReg  = value; }
	void setLBAHigh(uint8_t value) { cylinderHighReg = value; }

	[[nodiscard]] MSXMotherBoard& getMotherBoard() const { return motherBoard; }

private:
	/** Perform diagnostic and return result.
	  * Actually, just return success, because we don't emulate faulty hardware.
	  */
	[[nodiscard]] uint8_t diagnostic() const;

	/** Puts special values in the sector address, sector count and device
	  * registers to identify the type of device.
	  * @param preserveDevice If true, preserve the value of the DEV bit;
	  *   if false, set the DEV bit to 0.
	  */
	void createSignature(bool preserveDevice = false);

	/** Puts the output for the IDENTIFY DEVICE command in the buffer.
	  * @param buffer Pointer to the start of the buffer.
	  *   The buffer must be at least 512 bytes in size.
	  */
	void createIdentifyBlock(AlignedBuffer& buffer);

	/** Initialises registers for a data transfer.
	  */
	void startReadTransfer();

	/** Initialises buffer related variables for the next data block.
	  * Calls readBlockStart() to deliver the actual data.
	  */
	void readNextBlock();

	/** Indicates that a read transfer starts.
	  */
	void setTransferRead(bool status);

	/** Initialises buffer related variables for the next data block.
	  * Make sure transferCount is initialised before calling this method.
	  */
	void writeNextBlock();

	/** Indicates that a write transfer starts.
	  */
	void setTransferWrite(bool status);

private:
	MSXMotherBoard& motherBoard;

	/** Data buffer shared by all transfers.
	  * The size must be a multiple of 512.
	  * Right now I don't see any reason to make it larger than the minimum
	  * size of 1 * 512.
	  */
	AlignedByteArray<512> buffer;

	/** Index of current read/write position in the buffer.
	  */
	unsigned transferIdx = 0; // avoid UMR on serialize

	/** Number of bytes remaining in the buffer.
	  */
	unsigned bufferLeft = 0;

	/** Number of bytes remaining in the transfer after this buffer.
	  * (total bytes remaining == transferCount + bufferLeft)
	  */
	unsigned transferCount = 0;

	// ATA registers:
	uint8_t errorReg;
	uint8_t sectorCountReg;
	uint8_t sectorNumReg;
	uint8_t cylinderLowReg;
	uint8_t cylinderHighReg;
	uint8_t devHeadReg;
	uint8_t statusReg;
	uint8_t featureReg;

	bool transferRead = false;
	bool transferWrite = false;
};

REGISTER_BASE_NAME_HELPER(AbstractIDEDevice, "IDEDevice");

} // namespace openmsx

#endif // ABSTRACTIDEDEVICE_HH

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1	#ifndef ABSTRACTIDEDEVICE_HH
2	#define ABSTRACTIDEDEVICE_HH
3
4	#include "IDEDevice.hh"
5
6	#include "serialize_meta.hh"
7
8	#include "AlignedBuffer.hh"
9
10	namespace openmsx {
11
12	class MSXMotherBoard;
13
14	class AbstractIDEDevice : public IDEDevice
15	{
16	public:
17	void reset(EmuTime time) override;
18
19	[[nodiscard]] uint16_t readData(EmuTime time) override;
20	[[nodiscard]] uint8_t readReg(uint4_t reg, EmuTime time) override;
21
22	void writeData(uint16_t value, EmuTime time) override;
23	void writeReg(uint4_t reg, uint8_t value, EmuTime time) override;
24
25	template<typename Archive>
26	void serialize(Archive& ar, unsigned version);
27
28	protected:
29	// Bit flags for the status register:
30	static constexpr uint8_t DRDY = 0x40;
31	static constexpr uint8_t DSC = 0x10;
32	static constexpr uint8_t DRQ = 0x08;
33	static constexpr uint8_t ERR = 0x01;
34
35	// Bit flags for the error register:
36	static constexpr uint8_t UNC = 0x40;
37	static constexpr uint8_t IDNF = 0x10;
38	static constexpr uint8_t ABORT = 0x04;
39
40	explicit AbstractIDEDevice(MSXMotherBoard& motherBoard);
41	~AbstractIDEDevice() override = default;
42
43	/** Is this device a packet (ATAPI) device?
44	* @return True iff this device supports the packet commands.
45	*/
46	[[nodiscard]] virtual bool isPacketDevice() = 0;
47
48	/** Gets the device name to insert as "model number" into the identify
49	* block.
50	* @return An ASCII string, up to 40 characters long.
51	*/
52	[[nodiscard]] virtual std::string_view getDeviceName() = 0;
53
54	/** Tells a subclass to fill the device specific parts of the identify
55	* block located in the buffer.
56	* The generic part is already written there.
57	* @param buffer Array of 512 bytes.
58	*/
59	virtual void fillIdentifyBlock(AlignedBuffer& buffer) = 0;
60
61	/** Called when a block of read data should be buffered by the controller:
62	* when the buffer is empty or at the start of the transfer.
63	* @param buffer Pointer to the start of a byte array.
64	* @param count Number of bytes to be filled by this method.
65	* This number will not exceed the array size nor the transfer length.
66	* @return The number of bytes that was added to the array,
67	* or 0 if the transfer was aborted (the implementation of this method
68	* must set the relevant error flags as well).
69	*/
70	[[nodiscard]] virtual unsigned readBlockStart(AlignedBuffer& buffer, unsigned count) = 0;
71
72	/** Called when a read transfer completes.
73	* The default implementation does nothing.
74	*/
75	virtual void readEnd();
76
77	/** Called when a block of written data has been buffered by the controller:
78	* when the buffer is full or at the end of the transfer.
79	* @param buffer Pointer to the start of a byte array.
80	* @param count Number of data bytes in the array.
81	*/
82	virtual void writeBlockComplete(AlignedBuffer& buffer, unsigned count) = 0;
83
84	/** Starts execution of an IDE command.
85	* Override this to implement additional commands and make sure you call
86	* the superclass implementation for all commands that you don't handle.
87	*/
88	virtual void executeCommand(uint8_t cmd);
89
90	/** Indicates an error: sets error register, error flag, aborts transfers.
91	* @param error Value to be written to the error register.
92	*/
93	void setError(uint8_t error);
94
95	/** Creates an LBA sector address from the contents of the sectorNumReg,
96	* cylinderLowReg, cylinderHighReg and devHeadReg registers.
97	*/
98	[[nodiscard]] unsigned getSectorNumber() const;
99
100	/** Gets the number of sectors indicated by the sector count register.
101	*/
102	[[nodiscard]] unsigned getNumSectors() const;
103
104	/** Writes the interrupt reason register.
105	* This is the same as register as sector count, but serves a different
106	* purpose.
107	*/
108	void setInterruptReason(uint8_t value);
109
110	/** Reads the byte count limit of a packet transfer in the registers.
111	* The cylinder low/high registers are used for this.
112	*/
113	[[nodiscard]] unsigned getByteCount() const;
114
115	/** Writes the byte count of a packet transfer in the registers.
116	* The cylinder low/high registers are used for this.
117	*/
118	void setByteCount(unsigned count);
119
120	/** Writes a 28-bit LBA sector number in the registers.
121	* The cylinder low/high registers are used for this.
122	*/
123	void setSectorNumber(unsigned lba);
124
125	/** Indicates the start of a read data transfer which uses blocks.
126	* The readBlockStart() method is called at the start of each block.
127	* The first block will be read immediately, so make sure you initialise
128	* all variables needed by readBlockStart() before calling this method.
129	* @param count Total number of bytes to transfer.
130	*/
131	void startLongReadTransfer(unsigned count);
132
133	/** Indicates the start of a read data transfer where all data fits
134	* into the buffer at once.
135	* @param count Total number of bytes to transfer.
136	* @return Pointer to the start of the buffer.
137	* The caller should write the data there.
138	* The relevant part of the buffer contains zeroes.
139	*/
140	[[nodiscard]] AlignedBuffer& startShortReadTransfer(unsigned count);
141
142	/** Aborts the read transfer in progress.
143	*/
144	void abortReadTransfer(uint8_t error);
145
146	/** Indicates the start of a write data transfer.
147	* @param count Total number of bytes to transfer.
148	*/
149	void startWriteTransfer(unsigned count);
150
151	/** Aborts the write transfer in progress.
152	*/
153	void abortWriteTransfer(uint8_t error);
154
155	[[nodiscard]] uint8_t getFeatureReg() const { return featureReg; }
156	void setLBALow (uint8_t value) { sectorNumReg = value; }
157	void setLBAMid (uint8_t value) { cylinderLowReg = value; }
158	void setLBAHigh(uint8_t value) { cylinderHighReg = value; }
159
160	[[nodiscard]] MSXMotherBoard& getMotherBoard() const { return motherBoard; }
161
162	private:
163	/** Perform diagnostic and return result.
164	* Actually, just return success, because we don't emulate faulty hardware.
165	*/
166	[[nodiscard]] uint8_t diagnostic() const;
167
168	/** Puts special values in the sector address, sector count and device
169	* registers to identify the type of device.
170	* @param preserveDevice If true, preserve the value of the DEV bit;
171	* if false, set the DEV bit to 0.
172	*/
173	void createSignature(bool preserveDevice = false);
174
175	/** Puts the output for the IDENTIFY DEVICE command in the buffer.
176	* @param buffer Pointer to the start of the buffer.
177	* The buffer must be at least 512 bytes in size.
178	*/
179	void createIdentifyBlock(AlignedBuffer& buffer);
180
181	/** Initialises registers for a data transfer.
182	*/
183	void startReadTransfer();
184
185	/** Initialises buffer related variables for the next data block.
186	* Calls readBlockStart() to deliver the actual data.
187	*/
188	void readNextBlock();
189
190	/** Indicates that a read transfer starts.
191	*/
192	void setTransferRead(bool status);
193
194	/** Initialises buffer related variables for the next data block.
195	* Make sure transferCount is initialised before calling this method.
196	*/
197	void writeNextBlock();
198
199	/** Indicates that a write transfer starts.
200	*/
201	void setTransferWrite(bool status);
202
203	private:
204	MSXMotherBoard& motherBoard;
205
206	/** Data buffer shared by all transfers.
207	* The size must be a multiple of 512.
208	* Right now I don't see any reason to make it larger than the minimum
209	* size of 1 * 512.
210	*/
211	AlignedByteArray<512> buffer;
212
213	/** Index of current read/write position in the buffer.
214	*/
215	unsigned transferIdx = 0; // avoid UMR on serialize
216
217	/** Number of bytes remaining in the buffer.
218	*/
219	unsigned bufferLeft = 0;
220
221	/** Number of bytes remaining in the transfer after this buffer.
222	* (total bytes remaining == transferCount + bufferLeft)
223	*/
224	unsigned transferCount = 0;
225
226	// ATA registers:
227	uint8_t errorReg;
228	uint8_t sectorCountReg;
229	uint8_t sectorNumReg;
230	uint8_t cylinderLowReg;
231	uint8_t cylinderHighReg;
232	uint8_t devHeadReg;
233	uint8_t statusReg;
234	uint8_t featureReg;
235
236	bool transferRead = false;
237	bool transferWrite = false;
238	};
239
240	REGISTER_BASE_NAME_HELPER(AbstractIDEDevice, "IDEDevice");
241
242	} // namespace openmsx
243
244	#endif // ABSTRACTIDEDEVICE_HH

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