3b1emu: src/wd2010.c@7fb4f58f620a (annotated)

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src/wd2010.c@7fb4f58f620a (annotated)

src/wd2010.c

Wed, 16 Jan 2013 00:38:13 +0000

author: Philip Pemberton <philpem@philpem.me.uk>
date: Wed, 16 Jan 2013 00:38:13 +0000
changeset 125: 7fb4f58f620a
parent 124: ecaec4cfc644
child 126: d79a028161fd
permissions: -rw-r--r--

[wd2010] properly constrain R/W ops based on end sector

 #include <stdint.h>
 #include <stdbool.h>
 #include <malloc.h>
 #include "SDL.h"
 #include "musashi/m68k.h"
 #include "wd2010.h"
 #define WD2010_DEBUG
 #ifndef WD2010_DEBUG
 #define NDEBUG
 #endif
 #include "utils.h"
 #define SEEK_DELAY 30
 #define CMD_ENABLE_RETRY 0x01
 #define CMD_LONG_MODE 0x02
 #define CMD_MULTI_SECTOR 0x04
 #define CMD_INTRQ_WHEN_COMPLETE 0x08
 #define ER_BAD_BLOCK 0x80
 #define ER_CRC 0x40
 #define ER_ID_NOT_FOUND 0x10
 #define ER_ABORTED_COMMAND 0x04
 #define ER_NO_TK0 0x02
 #define ER_NO_ADDRESS_MARK 0x01
 #define SR_BUSY 0x80
 #define SR_READY 0x40
 #define SR_WRITE_FAULT 0x20
 #define SR_SEEK_COMPLETE 0x10
 #define SR_DRQ 0x08
 #define SR_CORRECTED 0x04
 #define SR_COMMAND_IN_PROGRESS 0x02
 #define SR_ERROR 0x01
 extern int cpu_log_enabled;
 /// WD2010 command constants
 enum {
 	CMD_MASK				= 0xF0,		///< Bit mask to detect command bits
 	CMD_2010_EXT			= 0x00,		///< WD2010 extended commands (compute correction, set parameter)
 	CMD_RESTORE				= 0x10,		///< Restore (recalibrate, seek to track 0)
 	CMD_READ_SECTOR			= 0x20,		///< Read sector
 	CMD_WRITE_SECTOR		= 0x30,		///< Write sector
 	CMD_SCAN_ID				= 0x40,		///< Scan ID
 	CMD_WRITE_FORMAT		= 0x50,		///< Write format
 	CMD_SEEK				= 0x70,		///< Seek to given track
 };
 int wd2010_init(WD2010_CTX *ctx, FILE *fp, int secsz, int spt, int heads)
 {
 	size_t filesize;
 	wd2010_reset(ctx);
 	// Start by finding out how big the image file is
 	fseek(fp, 0, SEEK_END);
 	filesize = ftell(fp);
 	fseek(fp, 0, SEEK_SET);
 	// Now figure out how many tracks it contains
 	unsigned int tracks = filesize / secsz / spt / heads;
 	// Confirm...
 	if (tracks < 1) {
 		return WD2010_ERR_BAD_GEOM;
 	}
 	LOG("WD2010 initialised, %d cylinders, %d heads, %d sectors per track", tracks, heads, spt);
 	// Allocate enough memory to store one disc track
 	if (ctx->data) {
 		free(ctx->data);
 	}
 	ctx->data = malloc(secsz * spt);
 	if (!ctx->data)
 		return WD2010_ERR_NO_MEMORY;
 	// Load the image and the geometry data
 	ctx->disc_image = fp;
 	ctx->geom_tracks = tracks;
 	ctx->geom_secsz = secsz;
 	ctx->geom_heads = heads;
 	ctx->geom_spt = spt;
 	return WD2010_ERR_OK;
 }
 void wd2010_reset(WD2010_CTX *ctx)
 {
 	// track, head and sector unknown
 	ctx->track = ctx->head = ctx->sector = 0;
 	// no IRQ pending
 	ctx->irq = false;
 	// no data available
 	ctx->data_pos = ctx->data_len = 0;
 	// Status register clear, not busy
 	ctx->status = 0;
 	ctx->sector_count = 0;
 	ctx->sector_number = 0;
 	ctx->cylinder_low_reg = 0;
 	ctx->cylinder_high_reg = 0;
 	ctx->sdh = 0;
 	ctx->mcr2_hdsel3 = 0;
 	ctx->mcr2_ddrive1 = 0;
 }
 void wd2010_done(WD2010_CTX *ctx)
 {
 	// Reset the WD2010
 	wd2010_reset(ctx);
 	// Free any allocated memory
 	if (ctx->data) {
 		free(ctx->data);
 		ctx->data = NULL;
 	}
 }
 bool wd2010_get_irq(WD2010_CTX *ctx)
 {
 	return ctx->irq;
 }
 bool wd2010_get_drq(WD2010_CTX *ctx)
 {
 	return (ctx->drq && ctx->data_pos < ctx->data_len);
 }
 void wd2010_dma_miss(WD2010_CTX *ctx)
 {
 	ctx->data_pos = ctx->data_len;
 	ctx->write_pos = 0;
 	ctx->status = SR_READY | SR_SEEK_COMPLETE;
 	ctx->irq = true;
 }
 uint8_t wd2010_read_data(WD2010_CTX *ctx)
 {
 	// If there's data in the buffer, return it. Otherwise return 0xFF.
 	if (ctx->data_pos < ctx->data_len) {
 		if (ctx->multi_sector && (ctx->data_pos > 0) && ((ctx->data_pos % ctx->geom_secsz) == 0)){
 			ctx->sector_count--;
 			ctx->sector_number++;
 		}
 		// set IRQ if this is the last data byte
 		if (ctx->data_pos == (ctx->data_len-1)) {
 			ctx->status = SR_READY | SR_SEEK_COMPLETE;
 			// Set IRQ
 			ctx->irq = true;
 			ctx->drq = false;
 		}
 		// return data byte and increment pointer
 		return ctx->data[ctx->data_pos++];
 	} else {
 		// empty buffer (this shouldn't happen)
 		LOGS("WD2010: attempt to read from empty data buffer");
 		return 0xff;
 	}
 }
 void wd2010_write_data(WD2010_CTX *ctx, uint8_t val)
 {
 	// If we're processing a write command, and there's space in the
 	// buffer, allow the write.
 	if (ctx->write_pos >= 0 && ctx->data_pos < ctx->data_len) {
 		// store data byte and increment pointer
 		if (ctx->multi_sector && (ctx->data_pos > 0) && ((ctx->data_pos % ctx->geom_secsz) == 0)){
 			ctx->sector_count--;
 			ctx->sector_number++;
 		}
 		ctx->data[ctx->data_pos++] = val;
 		// set IRQ and write data if this is the last data byte
 		if (ctx->data_pos == ctx->data_len) {
 			if (!ctx->formatting){
 				fseek(ctx->disc_image, ctx->write_pos, SEEK_SET);
 				fwrite(ctx->data, 1, ctx->data_len, ctx->disc_image);
 				fflush(ctx->disc_image);
 			}
 			ctx->formatting = false;
 			ctx->status = SR_READY | SR_SEEK_COMPLETE;
 			// Set IRQ and reset write pointer
 			ctx->irq = true;
 			ctx->write_pos = -1;
 			ctx->drq = false;
 		}
 	}else{
 		LOGS("WD2010: attempt to write to data buffer without a write command in progress");
 	}
 }
 uint32_t seek_complete(uint32_t interval, WD2010_CTX *ctx)
 {
 	/*m68k_end_timeslice();*/
 	ctx->status = SR_READY | SR_SEEK_COMPLETE;
 	ctx->irq = true;
 	return (0);
 }
 uint32_t transfer_seek_complete(uint32_t interval, WD2010_CTX *ctx)
 {
 	/*m68k_end_timeslice();*/
 	ctx->drq = true;
 	return (0);
 }
 uint8_t wd2010_read_reg(WD2010_CTX *ctx, uint8_t addr)
 {
 	uint8_t temp = 0;
 	/*cpu_log_enabled = 1;*/
 	switch (addr & 0x07) {
 		case WD2010_REG_ERROR:
 			return ctx->error_reg;
 		case WD2010_REG_SECTOR_COUNT:
 			return ctx->sector_count;
 		case WD2010_REG_SECTOR_NUMBER:
 			return ctx->sector_number;
 		case WD2010_REG_CYLINDER_HIGH:      // High byte of cylinder
 			return ctx->cylinder_high_reg;
 		case WD2010_REG_CYLINDER_LOW:       // Low byte of cylinder
 			return ctx->cylinder_low_reg;
 		case WD2010_REG_SDH:
 			return ctx->sdh;
 		case WD2010_REG_STATUS:             // Status register
 			// Read from status register clears IRQ
 			ctx->irq = false;
 			// Get current status flags (set by last command)
 			// DRQ bit
 			if (ctx->cmd_has_drq) {
 				temp = ctx->status & ~(SR_BUSY & SR_DRQ);
 				temp |= (ctx->data_pos < ctx->data_len) ? SR_DRQ : 0;
 				LOG("\tWDFDC rd sr, has drq, pos=%lu len=%lu, sr=0x%02X", ctx->data_pos, ctx->data_len, temp);
 			} else {
 				temp = ctx->status & ~0x80;
 			}
 			/*XXX: where should 0x02 (command in progress) be set? should it be set here instead of 0x80 (busy)?*/
 			// HDC is busy if there is still data in the buffer
 			temp |= (ctx->data_pos < ctx->data_len) ? SR_BUSY : 0;	// if data in buffer, then DMA hasn't copied it yet, and we're still busy!
 																	// TODO: also if seek delay / read delay hasn't passed (but that's for later)
 			/*XXX: should anything else be set here?*/
 			return temp;
 		default:
 			// shut up annoying compilers which don't recognise unreachable code when they see it
 			// (here's looking at you, gcc!)
 			return 0xff;
 	}
 }
 void wd2010_write_reg(WD2010_CTX *ctx, uint8_t addr, uint8_t val)
 {
 	uint8_t cmd = val & CMD_MASK;
 	size_t lba;
 	int new_track;
 	int sector_count;
 	m68k_end_timeslice();
 	/*cpu_log_enabled = 1;*/
 	if (addr == UNIXPC_REG_MCR2) {
 		// The UNIX PC has an "MCR2" register with the following format:
 		//   [ 7..2 ][1][0]
 		//   Bits 7..2: Not used
 		//   Bit 1:     DDRIVE1 (hard disk drive 1 select - not used?)
 		//   Bit 0:     HDSEL3  (head-select bit 3)
 		ctx->mcr2_hdsel3 = ((val & 1) == 1);
 		ctx->mcr2_ddrive1 = ((val & 2) == 2);
 		return;
 	}
 	switch (addr & 0x07) {
 		case WD2010_REG_WRITE_PRECOMP_CYLINDER:
 			break;
 		case WD2010_REG_SECTOR_COUNT:
 			ctx->sector_count = val;
 			break;
 		case WD2010_REG_SECTOR_NUMBER:
 			ctx->sector_number = val;
 			break;
 		case WD2010_REG_CYLINDER_HIGH:		// High byte of cylinder
 			ctx->cylinder_high_reg = val;
 			break;
 		case WD2010_REG_CYLINDER_LOW:		// Low byte of cylinder
 			ctx->cylinder_low_reg = val;
 			break;
 		case WD2010_REG_SDH:
 			/*XXX: remove this once the DMA page fault test passes (unless this is actually the correct behavior here)*/
 			ctx->data_pos = ctx->data_len = 0;
 			ctx->sdh = val;
 			break;
 		case WD2010_REG_COMMAND:	// Command register
 			// write to command register clears interrupt request
 			ctx->irq = false;
 			ctx->error_reg = 0;
 			/*cpu_log_enabled = 1;*/
 			switch (cmd) {
 				case CMD_RESTORE:
 					// Restore. Set track to 0 and throw an IRQ.
 					ctx->track = 0;
 					SDL_AddTimer(SEEK_DELAY, (SDL_NewTimerCallback)seek_complete, ctx);
 					break;
 				case CMD_SCAN_ID:
 					ctx->cylinder_high_reg = (ctx->track >> 8) & 0xff;
 					ctx->cylinder_low_reg = ctx->track & 0xff;
 					ctx->sector_number = ctx->sector;
 					ctx->sdh = (ctx->sdh & ~7) | (ctx->head & 7);
 				case CMD_WRITE_FORMAT:
 				case CMD_SEEK:
 				case CMD_READ_SECTOR:
 				case CMD_WRITE_SECTOR:
 					// Seek. Seek to the track specced in the cylinder
 					// registers.
 					new_track = (ctx->cylinder_high_reg << 8) | ctx->cylinder_low_reg;
 					if (new_track < ctx->geom_tracks) {
 						ctx->track = new_track;
 					} else {
 						// Seek error. :(
 						ctx->status = SR_ERROR;
 						ctx->error_reg = ER_ID_NOT_FOUND;
 						ctx->irq = true;
 						break;
 					}
 					// The SDH register provides 3 head select bits; the 4th comes from MCR2.
 					ctx->head = (ctx->sdh & 0x07) + (ctx->mcr2_hdsel3 ? 8 : 0);
 					ctx->sector = ctx->sector_number;
 					ctx->formatting = cmd == CMD_WRITE_FORMAT;
 					switch (cmd){
 						case CMD_SEEK:
 							SDL_AddTimer(SEEK_DELAY, (SDL_NewTimerCallback)seek_complete, ctx);
 							break;
 						case CMD_READ_SECTOR:
 							/*XXX: does a separate function to set the head have to be added?*/
 							LOG("WD2010: READ SECTOR cmd=%02X chs=%d:%d:%d nsectors=%d", cmd, ctx->track, ctx->head, ctx->sector, ctx->sector_count);
 							// Read Sector
 							// Check to see if the cyl, hd and sec are valid
 							if ((ctx->track > (ctx->geom_tracks-1)) || (ctx->head > (ctx->geom_heads-1)) || ((ctx->sector + ctx->sector_count - 1) > ctx->geom_spt-1)) {
 								LOG("*** WD2010 ALERT: CHS parameter limit exceeded! CHS=%d:%d:%d, nSecs=%d, endSec=%d maxCHS=%d:%d:%d",
 										ctx->track, ctx->head, ctx->sector,
 										ctx->sector_count,
 										ctx->sector + ctx->sector_count - 1,
 										ctx->geom_tracks-1, ctx->geom_heads-1, ctx->geom_spt);
 								// CHS parameters exceed limits
 								ctx->status = SR_ERROR;
 								ctx->error_reg = ER_ID_NOT_FOUND;
 								// Set IRQ
 								ctx->irq = true;
 								break;
 							}
 							// reset data pointers
 							ctx->data_pos = ctx->data_len = 0;
 							if (val & CMD_MULTI_SECTOR){
 								ctx->multi_sector = 1;
 								sector_count = ctx->sector_count;
 							}else{
 								ctx->multi_sector = 0;
 								sector_count = 1;
 							}
 							for (int i=0; i<sector_count; i++) {
 								// Calculate the LBA address of the required sector
 								// LBA = (C * nHeads * nSectors) + (H * nSectors) + S - 1
 								lba = (((ctx->track * ctx->geom_heads * ctx->geom_spt) + (ctx->head * ctx->geom_spt) + ctx->sector) + i);
 								// convert LBA to byte address
 								lba *= ctx->geom_secsz;
 								LOG("\tREAD lba = %lu", lba);
 								// Read the sector from the file
 								fseek(ctx->disc_image, lba, SEEK_SET);
 								// TODO: check fread return value! if < secsz, BAIL! (call it a crc error or secnotfound maybe? also log to stderr)
 								ctx->data_len += fread(&ctx->data[ctx->data_len], 1, ctx->geom_secsz, ctx->disc_image);
 								LOG("\tREAD len=%lu, pos=%lu, ssz=%d", ctx->data_len, ctx->data_pos, ctx->geom_secsz);
 							}
 							ctx->status = 0;
 							ctx->status |= (ctx->data_pos < ctx->data_len) ? SR_DRQ | SR_COMMAND_IN_PROGRESS | SR_BUSY : 0x00;
 							SDL_AddTimer(SEEK_DELAY, (SDL_NewTimerCallback)transfer_seek_complete, ctx);
 							break;
 						case CMD_WRITE_FORMAT:
 							ctx->sector = 0;
 						case CMD_WRITE_SECTOR:
 							LOG("WD2010: WRITE SECTOR cmd=%02X chs=%d:%d:%d nsectors=%d", cmd, ctx->track, ctx->head, ctx->sector, ctx->sector_count);
 							// Write Sector
 							// Check to see if the cyl, hd and sec are valid
 							if ((ctx->track > (ctx->geom_tracks-1)) || (ctx->head > (ctx->geom_heads-1)) || ((ctx->sector + ctx->sector_count - 1) > ctx->geom_spt-1)) {
 								LOG("*** WD2010 ALERT: CHS parameter limit exceeded! CHS=%d:%d:%d, nSecs=%d, endSec=%d maxCHS=%d:%d:%d",
 										ctx->track, ctx->head, ctx->sector,
 										ctx->sector_count,
 										ctx->sector + ctx->sector_count - 1,
 										ctx->geom_tracks-1, ctx->geom_heads-1, ctx->geom_spt);
 								// CHS parameters exceed limits
 								ctx->status = SR_ERROR;
 								ctx->error_reg = ER_ID_NOT_FOUND;
 								// Set IRQ
 								ctx->irq = true;
 								break;
 							}
 							// reset data pointers
 							ctx->data_pos = ctx->data_len = 0;
 							if (val & CMD_MULTI_SECTOR){
 								ctx->multi_sector = 1;
 								sector_count = ctx->sector_count;
 							}else{
 								ctx->multi_sector = 0;
 								sector_count = 1;
 							}
 							ctx->data_len = ctx->geom_secsz * sector_count;
 							lba = (((ctx->track * ctx->geom_heads * ctx->geom_spt) + (ctx->head * ctx->geom_spt) + ctx->sector));
 							// convert LBA to byte address
 							ctx->write_pos = (lba *= ctx->geom_secsz);
 							LOG("\tWRITE lba = %zu", lba);
 							ctx->status = 0;
 							ctx->status |= (ctx->data_pos < ctx->data_len) ? SR_DRQ | SR_COMMAND_IN_PROGRESS | SR_BUSY : 0x00;
 							SDL_AddTimer(SEEK_DELAY, (SDL_NewTimerCallback)transfer_seek_complete, ctx);
 							break;
 						default:
 							LOG("WD2010: invalid seeking command %x (this shouldn't happen!)\n", cmd);
 							break;
 					}
 					break;
 				case CMD_2010_EXT: /* not implemented */
 				default:
 					LOG("WD2010: unknown command %x\n", cmd);
 					ctx->status = SR_ERROR;
 					ctx->error_reg = ER_ABORTED_COMMAND;
 					ctx->irq = true;
 					break;
 			}
 			break;
 	}
 }

3b1emu / annotate

src/wd2010.c@7fb4f58f620a (annotated)

src/wd2010.c