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BlueSCSI
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Optimize handling of reset interrupt.

This commit is contained in:
Glenn Anderson 2022-03-14 12:43:57 -07:00
parent 072c50a7f9
commit bc65933625
1 changed files with 80 additions and 37 deletions
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117
src/BlueSCSI.cpp
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@ -37,6 +37,7 @@
#include <Arduino.h> // For Platform.IO
#include <SdFat.h>
#include <setjmp.h>
#ifdef USE_STM32_DMA
#warning "warning USE_STM32_DMA"
@ -187,6 +188,8 @@ HDDIMG img[NUM_SCSIID][NUM_SCSILUN]; // Maximum number
uint8_t m_senseKey = 0; // Sense key
unsigned m_addition_sense = 0; // Additional sense information
volatile bool m_isBusReset = false; // Bus reset
volatile bool m_resetJmp = false; // Call longjmp on reset
jmp_buf m_resetJmpBuf;
byte scsi_id_mask; // Mask list of responding SCSI IDs
byte m_id; // Currently responding SCSI-ID
@ -416,7 +419,7 @@ void setup()
SCSI_TARGET_INACTIVE()
//Occurs when the RST pin state changes from HIGH to LOW
//attachInterrupt(PIN_MAP[RST].gpio_bit, onBusReset, FALLING);
//attachInterrupt(RST, onBusReset, FALLING);
LED_ON();
@ -519,7 +522,7 @@ void setup()
finalizeFileLog();
LED_OFF();
//Occurs when the RST pin state changes from HIGH to LOW
attachInterrupt(PIN_MAP[RST].gpio_bit, onBusReset, FALLING);
attachInterrupt(RST, onBusReset, FALLING);
}
/*
@ -612,6 +615,36 @@ void noSDCardFound(void)
}
}
/*
* Return from exception and call longjmp
*/
void __attribute__ ((noinline)) longjmpFromInterrupt(jmp_buf jmpb, int retval) __attribute__ ((noreturn));
void longjmpFromInterrupt(jmp_buf jmpb, int retval) {
// Address of longjmp with the thumb bit cleared
const uint32_t longjmpaddr = ((uint32_t)longjmp) & 0xfffffffe;
const uint32_t zero = 0;
// Default PSR value, function calls don't require any particular value
const uint32_t PSR = 0x01000000;
// For documentation on what this is doing, see:
// https://developer.arm.com/documentation/dui0552/a/the-cortex-m3-processor/exception-model/exception-entry-and-return
// Stack frame needs to have R0-R3, R12, LR, PC, PSR (from bottom to top)
// This is being set up to have R0 and R1 contain the parameters passed to longjmp, and PC is the address of the longjmp function.
// This is using existing stack space, rather than allocating more, as longjmp is just going to unroll the stack even further.
// 0xfffffff9 is the EXC_RETURN value to return to thread mode.
asm (
"str %0, [sp];\
str %1, [sp, #4];\
str %2, [sp, #8];\
str %2, [sp, #12];\
str %2, [sp, #16];\
str %2, [sp, #20];\
str %3, [sp, #24];\
str %4, [sp, #28];\
ldr lr, =0xfffffff9"
:: "r"(jmpb),"r"(retval),"r"(zero), "r"(longjmpaddr), "r"(PSR)
);
}
/*
* Bus reset interrupt.
*/
@ -635,10 +668,28 @@ void onBusReset(void)
SCSI_DB_INPUT()
LOGN("BusReset!");
m_isBusReset = true;
if (m_resetJmp) {
m_resetJmp = false;
// Jumping out of the interrupt handler, so need to clear the interupt source.
uint8 exti = PIN_MAP[RST].gpio_bit;
EXTI_BASE->PR = (1U << exti);
longjmpFromInterrupt(m_resetJmpBuf, 1);
} else {
m_isBusReset = true;
}
}
}
}
/*
* Enable the reset longjmp, and check if reset fired while it was disabled.
*/
void enableResetJmp(void) {
m_resetJmp = true;
if (m_isBusReset) {
longjmp(m_resetJmpBuf, 1);
}
}
/*
* Read by handshake.
@ -647,10 +698,10 @@ inline byte readHandshake(void)
{
SCSI_OUT(vREQ,active)
//SCSI_DB_INPUT()
while( ! SCSI_IN(vACK)) { if(m_isBusReset) return 0; }
while( ! SCSI_IN(vACK));
byte r = readIO();
SCSI_OUT(vREQ,inactive)
while( SCSI_IN(vACK)) { if(m_isBusReset) return 0; }
while( SCSI_IN(vACK));
return r;
}
@ -667,12 +718,12 @@ inline void writeHandshake(byte d)
SCSI_OUT(vREQ,inactive) // setup wait (30ns)
SCSI_OUT(vREQ,active) // (30ns)
//while(!SCSI_IN(vACK)) { if(m_isBusReset){ SCSI_DB_INPUT() return; }}
while(!m_isBusReset && !SCSI_IN(vACK));
while(!SCSI_IN(vACK));
// ACK.Fall to REQ.Raise delay 500ns(typ.) (DTC-510B)
GPIOB->regs->BSRR = DBP(0xff); // DB=0xFF , SCSI_OUT(vREQ,inactive)
// REQ.Raise to DB hold time 0ns
SCSI_DB_INPUT() // (150ns)
while( SCSI_IN(vACK)) { if(m_isBusReset) return; }
while( SCSI_IN(vACK));
}
/*
@ -686,9 +737,6 @@ void writeDataPhase(int len, const byte* p)
SCSI_OUT(vCD ,inactive) // gpio_write(CD, low);
SCSI_OUT(vIO , active) // gpio_write(IO, high);
for (int i = 0; i < len; i++) {
if(m_isBusReset) {
return;
}
writeHandshake(p[i]);
}
}
@ -709,7 +757,9 @@ void writeDataPhaseSD(uint32_t adds, uint32_t len)
for(uint32_t i = 0; i < len; i++) {
// Asynchronous reads will make it faster ...
m_resetJmp = false;
m_img->m_file.read(m_buf, m_img->m_blocksize);
enableResetJmp();
#if READ_SPEED_OPTIMIZE
@ -718,8 +768,8 @@ void writeDataPhaseSD(uint32_t adds, uint32_t len)
#define FETCH_SRC() (src_byte = *srcptr++)
#define FETCH_BSRR_DB() (bsrr_val = bsrr_tbl[src_byte])
#define REQ_OFF_DB_SET(BSRR_VAL) *db_dst = BSRR_VAL
#define WAIT_ACK_ACTIVE() while(!m_isBusReset && !SCSI_IN(vACK))
#define WAIT_ACK_INACTIVE() do{ if(m_isBusReset) return; }while(SCSI_IN(vACK))
#define WAIT_ACK_ACTIVE() while(!SCSI_IN(vACK))
#define WAIT_ACK_INACTIVE() while(SCSI_IN(vACK))
SCSI_DB_OUTPUT()
register byte *srcptr= m_buf; // Source buffer
@ -799,9 +849,6 @@ void writeDataPhaseSD(uint32_t adds, uint32_t len)
SCSI_DB_INPUT()
#else
for(int j = 0; j < m_img->m_blocksize; j++) {
if(m_isBusReset) {
return;
}
writeHandshake(m_buf[j]);
}
#endif
@ -835,6 +882,7 @@ void readDataPhaseSD(uint32_t adds, uint32_t len)
SCSI_OUT(vCD ,inactive) // gpio_write(CD, low);
SCSI_OUT(vIO ,inactive) // gpio_write(IO, low);
for(uint32_t i = 0; i < len; i++) {
m_resetJmp = true;
#if WRITE_SPEED_OPTIMIZE
register byte *dstptr= m_buf;
register byte *endptr= m_buf + m_img->m_blocksize;
@ -848,21 +896,21 @@ void readDataPhaseSD(uint32_t adds, uint32_t len)
dstptr[5] = readHandshake();
dstptr[6] = readHandshake();
dstptr[7] = readHandshake();
if(m_isBusReset) {
return;
}
}
#else
for(int j = 0; j < m_img->m_blocksize; j++) {
if(m_isBusReset) {
return;
}
m_buf[j] = readHandshake();
}
#endif
m_resetJmp = false;
m_img->m_file.write(m_buf, m_img->m_blocksize);
// If a reset happened while writing, break and let the flush happen before it is handled.
if (m_isBusReset) {
break;
}
}
m_img->m_file.flush();
enableResetJmp();
}
/*
@ -1235,6 +1283,11 @@ void loop()
}
LOGN("Selection");
m_isBusReset = false;
if (setjmp(m_resetJmpBuf) == 1) {
LOGN("Reset, going to BusFree");
goto BusFree;
}
enableResetJmp();
// Set BSY to-when selected
SCSI_BSY_ACTIVE(); // Turn only BSY output ON, ACTIVE
@ -1243,9 +1296,6 @@ void loop()
// Wait until SEL becomes inactive
while(isHigh(gpio_read(SEL)) && isLow(gpio_read(BSY))) {
if(m_isBusReset) {
goto BusFree;
}
}
SCSI_TARGET_ACTIVE() // (BSY), REQ, MSG, CD, IO output turned on
//
@ -1308,22 +1358,21 @@ void loop()
int len;
byte cmd[12];
cmd[0] = readHandshake(); if(m_isBusReset) goto BusFree;
cmd[0] = readHandshake();
LOGHEX(cmd[0]);
// Command length selection, reception
static const int cmd_class_len[8]={6,10,10,6,6,12,6,6};
len = cmd_class_len[cmd[0] >> 5];
cmd[1] = readHandshake(); LOG(":");LOGHEX(cmd[1]); if(m_isBusReset) goto BusFree;
cmd[2] = readHandshake(); LOG(":");LOGHEX(cmd[2]); if(m_isBusReset) goto BusFree;
cmd[3] = readHandshake(); LOG(":");LOGHEX(cmd[3]); if(m_isBusReset) goto BusFree;
cmd[4] = readHandshake(); LOG(":");LOGHEX(cmd[4]); if(m_isBusReset) goto BusFree;
cmd[5] = readHandshake(); LOG(":");LOGHEX(cmd[5]); if(m_isBusReset) goto BusFree;
cmd[1] = readHandshake(); LOG(":");LOGHEX(cmd[1]);
cmd[2] = readHandshake(); LOG(":");LOGHEX(cmd[2]);
cmd[3] = readHandshake(); LOG(":");LOGHEX(cmd[3]);
cmd[4] = readHandshake(); LOG(":");LOGHEX(cmd[4]);
cmd[5] = readHandshake(); LOG(":");LOGHEX(cmd[5]);
// Receive the remaining commands
for(int i = 6; i < len; i++ ) {
cmd[i] = readHandshake();
LOG(":");
LOGHEX(cmd[i]);
if(m_isBusReset) goto BusFree;
}
// LUN confirmation
m_sts = cmd[1]&0xe0; // Preset LUN in status byte
@ -1422,18 +1471,12 @@ void loop()
m_addition_sense = 0x2000; // Invalid Command Operation Code
break;
}
if(m_isBusReset) {
goto BusFree;
}
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);
writeHandshake(m_sts);
if(m_isBusReset) {
goto BusFree;
}
LOGN("MsgIn");
SCSI_OUT(vMSG, active) // gpio_write(MSG, high);