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Cleanup of SCSI phase change code, and adjustment of bus settle delays. #88

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Apr 13, 2022
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Cleanup of SCSI phase change code, and adjustment of bus settle delays. #88

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171 changes: 83 additions & 88 deletions src/BlueSCSI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -152,6 +152,18 @@ SdFs SD;
// SCSI input pin check (inactive=0,avtive=1)
#define SCSI_IN(VPIN) ((~GPIOREG(VPIN)->IDR>>(VPIN&15))&1)

// SCSI phase change as single write to port B
#define SCSIPHASEMASK(MSGACTIVE, CDACTIVE, IOACTIVE) ((BITMASK(vMSG)<<((MSGACTIVE)?16:0)) | (BITMASK(vCD)<<((CDACTIVE)?16:0)) | (BITMASK(vIO)<<((IOACTIVE)?16:0)))

#define SCSI_PHASE_DATAOUT SCSIPHASEMASK(inactive, inactive, inactive)
#define SCSI_PHASE_DATAIN SCSIPHASEMASK(inactive, inactive, active)
#define SCSI_PHASE_COMMAND SCSIPHASEMASK(inactive, active, inactive)
#define SCSI_PHASE_STATUS SCSIPHASEMASK(inactive, active, active)
#define SCSI_PHASE_MESSAGEOUT SCSIPHASEMASK(active, active, inactive)
#define SCSI_PHASE_MESSAGEIN SCSIPHASEMASK(active, active, active)

#define SCSI_PHASE_CHANGE(MASK) { PBREG->BSRR = (MASK); }

// GPIO mode
// IN , FLOAT : 4
// IN , PU/PD : 8
Expand All @@ -171,7 +183,7 @@ SdFs SD;
// BSY,REQ,MSG,CD,IO Turn on the output (no change required for OD)
#define SCSI_TARGET_ACTIVE() { if (DB_MODE_OUT != 7) gpio_mode(REQ, GPIO_OUTPUT_PP);}
// BSY,REQ,MSG,CD,IO Turn off output, BSY is the last input
#define SCSI_TARGET_INACTIVE() { if (DB_MODE_OUT == 7) SCSI_OUT(vREQ,inactive) else { if (DB_MODE_IN == 8) gpio_mode(REQ, GPIO_INPUT_PU) else gpio_mode(REQ, GPIO_INPUT_FLOATING)} SCSI_OUT(vMSG,inactive); SCSI_OUT(vCD,inactive);SCSI_OUT(vIO,inactive); gpio_mode(BSY, GPIO_INPUT_PU); }
#define SCSI_TARGET_INACTIVE() { if (DB_MODE_OUT == 7) SCSI_OUT(vREQ,inactive) else { if (DB_MODE_IN == 8) gpio_mode(REQ, GPIO_INPUT_PU) else gpio_mode(REQ, GPIO_INPUT_FLOATING)} SCSI_PHASE_CHANGE(SCSI_PHASE_DATAOUT); gpio_mode(BSY, GPIO_INPUT_PU); }

// HDDiamge file
#define HDIMG_ID_POS 2 // Position to embed ID number
Expand Down Expand Up @@ -201,7 +213,6 @@ byte m_sts; // Status byte
byte m_msg; // Message bytes
HDDIMG *m_img; // HDD image for current SCSI-ID, LUN
byte m_buf[MAX_BLOCKSIZE]; // General purpose buffer
int m_msc;
byte m_msb[256]; // Command storage bytes

/*
Expand Down Expand Up @@ -775,6 +786,7 @@ inline byte readHandshake(void)
*/
inline void writeHandshake(byte d)
{
// This has a 400ns bus settle delay built in. Not optimal for multi-byte transfers.
GPIOB->regs->BSRR = db_bsrr[d]; // setup DB,DBP (160ns)
SCSI_DB_OUTPUT() // (180ns)
// ACK.Fall to DB output delay 100ns(MAX) (DTC-510B)
Expand All @@ -791,21 +803,6 @@ inline void writeHandshake(byte d)
while( SCSI_IN(vACK));
}

/*
* Data in phase.
* Send len bytes of data array p.
*/
void writeDataPhase(int len, const byte* p)
{
LOGN("DATAIN PHASE");
SCSI_OUT(vMSG,inactive) // gpio_write(MSG, low);
SCSI_OUT(vCD ,inactive) // gpio_write(CD, low);
SCSI_OUT(vIO , active) // gpio_write(IO, high);
for (int i = 0; i < len; i++) {
writeHandshake(p[i]);
}
}

#if READ_SPEED_OPTIMIZE
#pragma GCC push_options
#pragma GCC optimize ("-Os")
Expand All @@ -818,20 +815,19 @@ void writeDataPhase(int len, const byte* p)
* Alignment matters. For the 3 instruction wait loops,it looks like crossing
* an 8 byte prefetch buffer can add 2 cycles of wait every branch taken.
*/
void writeDataLoop(uint32_t blocksize) __attribute__ ((aligned(8)));
void writeDataLoop(uint32_t blocksize)
void writeDataLoop(uint32_t blocksize, const byte* srcptr) __attribute__ ((aligned(8)));
void writeDataLoop(uint32_t blocksize, const byte* srcptr)
{
#define REQ_ON() (port_b->BRR = req_bit);
#define FETCH_BSRR_DB() (bsrr_val = bsrr_tbl[*srcptr++])
#define REQ_OFF_DB_SET(BSRR_VAL) port_b->BSRR = BSRR_VAL;
#define WAIT_ACK_ACTIVE() while((*port_a_idr>>(vACK&15)&1))
#define WAIT_ACK_INACTIVE() while(!(*port_a_idr>>(vACK&15)&1))

register byte *srcptr= m_buf; // Source buffer
register byte *endptr= m_buf + blocksize; // End pointer
register const byte *endptr= srcptr + blocksize; // End pointer

register const uint32_t *bsrr_tbl = db_bsrr; // Table to convert to BSRR
register uint32_t bsrr_val; // BSRR value to output (DB, DBP, REQ = ACTIVE)
register const uint32_t *bsrr_tbl = db_bsrr; // Table to convert to BSRR
register uint32_t bsrr_val; // BSRR value to output (DB, DBP, REQ = ACTIVE)

register uint32_t req_bit = BITMASK(vREQ);
register gpio_reg_map *port_b = PBREG;
Expand Down Expand Up @@ -868,16 +864,34 @@ void writeDataLoop(uint32_t blocksize)
#pragma GCC pop_options
#endif

/*
/*
* Data in phase.
* Send len bytes of data array p.
*/
void writeDataPhase(int len, const byte* p)
{
LOGN("DATAIN PHASE");
SCSI_PHASE_CHANGE(SCSI_PHASE_DATAIN);
#if READ_SPEED_OPTIMIZE
// Bus settle delay 400ns. Following code was measured at 800ns before REQ asserted. STM32F103.
SCSI_DB_OUTPUT()
writeDataLoop(len, p);
SCSI_DB_INPUT()
#else
for (int i = 0; i < len; i++) {
writeHandshake(p[i]);
}
#endif
}

/*
* Data in phase.
* Send len block while reading from SD card.
*/
void writeDataPhaseSD(uint32_t adds, uint32_t len)
{
LOGN("DATAIN PHASE(SD)");
SCSI_OUT(vMSG,inactive) // gpio_write(MSG, low);
SCSI_OUT(vCD ,inactive) // gpio_write(CD, low);
SCSI_OUT(vIO , active) // gpio_write(IO, high);
SCSI_PHASE_CHANGE(SCSI_PHASE_DATAIN);
//Bus settle delay 400ns, file.seek() measured at over 1000ns.

uint32_t pos = adds * m_img->m_blocksize;
Expand All @@ -891,7 +905,7 @@ void writeDataPhaseSD(uint32_t adds, uint32_t len)
enableResetJmp();

#if READ_SPEED_OPTIMIZE
writeDataLoop(m_img->m_blocksize);
writeDataLoop(m_img->m_blocksize, m_buf);
#else
for(int j = 0; j < m_img->m_blocksize; j++) {
writeHandshake(m_buf[j]);
Expand All @@ -901,32 +915,17 @@ void writeDataPhaseSD(uint32_t adds, uint32_t len)
SCSI_DB_INPUT()
}

/*
* Data out phase.
* len block read
*/
void readDataPhase(int len, byte* p)
{
LOGN("DATAOUT PHASE");
SCSI_OUT(vMSG,inactive) // gpio_write(MSG, low);
SCSI_OUT(vCD ,inactive) // gpio_write(CD, low);
SCSI_OUT(vIO ,inactive) // gpio_write(IO, low);
for(uint32_t i = 0; i < len; i++)
p[i] = readHandshake();
}

#if WRITE_SPEED_OPTIMIZE
#pragma GCC push_options
#pragma GCC optimize ("-Os")

/*
* See writeDataLoop for optimization info.
*/
void readDataLoop(uint32_t blockSize) __attribute__ ((aligned(16)));
void readDataLoop(uint32_t blockSize)
void readDataLoop(uint32_t blockSize, byte* dstptr) __attribute__ ((aligned(16)));
void readDataLoop(uint32_t blockSize, byte* dstptr)
{
register byte *dstptr= m_buf;
register byte *endptr= m_buf + blockSize - 1;
register byte *endptr= dstptr + blockSize - 1;

#define REQ_ON() (port_b->BRR = req_bit);
#define REQ_OFF() (port_b->BSRR = req_bit);
Expand Down Expand Up @@ -958,24 +957,39 @@ void readDataLoop(uint32_t blockSize)
#pragma GCC pop_options
#endif

/*
* Data out phase.
* len block read
*/
void readDataPhase(int len, byte* p)
{
LOGN("DATAOUT PHASE");
SCSI_PHASE_CHANGE(SCSI_PHASE_DATAOUT);
// Bus settle delay 400ns. The following code was measured at 450ns before REQ asserted. STM32F103.
#if WRITE_SPEED_OPTIMIZE
readDataLoop(len, p);
#else
for(uint32_t i = 0; i < len; i++)
p[i] = readHandshake();
#endif
}

/*
* Data out phase.
* Write to SD card while reading len block.
*/
void readDataPhaseSD(uint32_t adds, uint32_t len)
{
LOGN("DATAOUT PHASE(SD)");
SCSI_OUT(vMSG,inactive) // gpio_write(MSG, low);
SCSI_OUT(vCD ,inactive) // gpio_write(CD, low);
SCSI_OUT(vIO ,inactive) // gpio_write(IO, low);
SCSI_PHASE_CHANGE(SCSI_PHASE_DATAOUT);
//Bus settle delay 400ns, file.seek() measured at over 1000ns.

uint32_t pos = adds * m_img->m_blocksize;
m_img->m_file.seek(pos);
for(uint32_t i = 0; i < len; i++) {
m_resetJmp = true;
#if WRITE_SPEED_OPTIMIZE
readDataLoop(m_img->m_blocksize);
readDataLoop(m_img->m_blocksize, m_buf);
#else
for(int j = 0; j < m_img->m_blocksize; j++) {
m_buf[j] = readHandshake();
Expand All @@ -999,16 +1013,14 @@ void readDataPhaseSD(uint32_t adds, uint32_t len)
void verifyDataPhaseSD(uint32_t adds, uint32_t len)
{
LOGN("DATAOUT PHASE(SD)");
SCSI_OUT(vMSG,inactive) // gpio_write(MSG, low);
SCSI_OUT(vCD ,inactive) // gpio_write(CD, low);
SCSI_OUT(vIO ,inactive) // gpio_write(IO, low);
SCSI_PHASE_CHANGE(SCSI_PHASE_DATAOUT);
//Bus settle delay 400ns, file.seek() measured at over 1000ns.

uint32_t pos = adds * m_img->m_blocksize;
m_img->m_file.seek(pos);
for(uint32_t i = 0; i < len; i++) {
#if WRITE_SPEED_OPTIMIZE
readDataLoop(m_img->m_blocksize);
readDataLoop(m_img->m_blocksize, m_buf);
#else
for(int j = 0; j < m_img->m_blocksize; j++) {
m_buf[j] = readHandshake();
Expand Down Expand Up @@ -1439,26 +1451,11 @@ static byte dtc510b_setDriveparameter(void)
void MsgIn2(int msg)
{
LOGN("MsgIn2");
SCSI_OUT(vMSG, active) // gpio_write(MSG, high);
SCSI_OUT(vCD , active) // gpio_write(CD, high);
SCSI_OUT(vIO , active) // gpio_write(IO, high);
SCSI_PHASE_CHANGE(SCSI_PHASE_MESSAGEIN);
// Bus settle delay 400ns built in to writeHandshake
writeHandshake(msg);
}

/*
* MsgOut2.
*/
void MsgOut2()
{
LOGN("MsgOut2");
SCSI_OUT(vMSG, active) // gpio_write(MSG, high);
SCSI_OUT(vCD , active) // gpio_write(CD, high);
SCSI_OUT(vIO ,inactive) // gpio_write(IO, low);
m_msb[m_msc] = readHandshake();
m_msc++;
m_msc %= 256;
}

/*
* Main loop.
*/
Expand Down Expand Up @@ -1498,17 +1495,18 @@ void loop()
SCSI_TARGET_ACTIVE() // (BSY), REQ, MSG, CD, IO output turned on
//
if(isHigh(gpio_read(ATN))) {
SCSI_PHASE_CHANGE(SCSI_PHASE_MESSAGEOUT);
// Bus settle delay 400ns. Following code was measured at 350ns before REQ asserted. Added another 50ns. STM32F103.
SCSI_PHASE_CHANGE(SCSI_PHASE_MESSAGEOUT);// 28ns delay STM32F103
SCSI_PHASE_CHANGE(SCSI_PHASE_MESSAGEOUT);// 28ns delay STM32F103
bool syncenable = false;
int syncperiod = 50;
int syncoffset = 0;
int loopWait = 0;
m_msc = 0;
memset(m_msb, 0x00, sizeof(m_msb));
while(isHigh(gpio_read(ATN)) && loopWait < 255) {
MsgOut2();
loopWait++;
int msc = 0;
while(isHigh(gpio_read(ATN)) && msc < 255) {
m_msb[msc++] = readHandshake();
}
for(int i = 0; i < m_msc; i++) {
for(int i = 0; i < msc; i++) {
// ABORT
if (m_msb[i] == 0x06) {
goto BusFree;
Expand Down Expand Up @@ -1550,10 +1548,9 @@ void loop()
}

LOG("Command:");
SCSI_OUT(vMSG,inactive) // gpio_write(MSG, low);
SCSI_OUT(vCD , active) // gpio_write(CD, high);
SCSI_OUT(vIO ,inactive) // gpio_write(IO, low);

SCSI_PHASE_CHANGE(SCSI_PHASE_COMMAND);
// Bus settle delay 400ns. The following code was measured at 20ns before REQ asserted. Added another 380ns. STM32F103.
asm("nop;nop;nop;nop;nop;nop;nop;nop");// This asm causes some code reodering, which adds 270ns, plus 8 nop cycles for an additional 110ns. STM32F103
int len;
byte cmd[12];
cmd[0] = readHandshake();
Expand Down Expand Up @@ -1686,15 +1683,13 @@ void loop()
}

LOGN("Sts");
SCSI_OUT(vMSG,inactive) // gpio_write(MSG, low);
SCSI_OUT(vCD , active) // gpio_write(CD, high);
SCSI_OUT(vIO , active) // gpio_write(IO, high);
SCSI_PHASE_CHANGE(SCSI_PHASE_STATUS);
// Bus settle delay 400ns built in to writeHandshake
writeHandshake(m_sts);

LOGN("MsgIn");
SCSI_OUT(vMSG, active) // gpio_write(MSG, high);
SCSI_OUT(vCD , active) // gpio_write(CD, high);
SCSI_OUT(vIO , active) // gpio_write(IO, high);
SCSI_PHASE_CHANGE(SCSI_PHASE_MESSAGEIN);
// Bus settle delay 400ns built in to writeHandshake
writeHandshake(m_msg);

BusFree:
Expand Down