static int sd_spi_init(uint8_t drive);
static void sd_spi_release(uint8_t drive);
static int sd_spi_wait_ready(uint8_t drive);
-static bool sd_spi_transmit_block(uint8_t drive, void *ptr, unsigned int length);
-static bool sd_spi_receive_block(uint8_t drive, void *ptr, unsigned int length);
+static bool sd_spi_transmit_sector(uint8_t drive, void *ptr, unsigned int length);
+static bool sd_spi_receive_sector(uint8_t drive, void *ptr, unsigned int length);
static int sd_send_command(uint8_t drive, unsigned char cmd, uint32_t arg);
static uint32_t sd_get_size_sectors(uint8_t drive);
static bool sd_read_sector(uint8_t drive, void *ptr, uint32_t lba);
return res;
}
-static bool sd_spi_transmit_block(uint8_t drive, void *ptr, unsigned int length)
+static bool sd_spi_transmit_sector(uint8_t drive, void *ptr, unsigned int length)
{
unsigned char reply;
return false; /* failed */
sd_spi_transmit_byte(drive, 0xFE);
- sd_spi_transmit_from_memory(drive, ptr, length);
+ sd_spi_transmit_block(drive, ptr, length);
sd_spi_transmit_byte(drive, 0xFF); /* dummy CRC */
sd_spi_transmit_byte(drive, 0xFF);
reply = sd_spi_receive_byte(drive);
return true; /* hooray! */
}
-static bool sd_spi_receive_block(uint8_t drive, void *ptr, unsigned int length)
+static bool sd_spi_receive_sector(uint8_t drive, void *ptr, unsigned int length)
{
unsigned int timer;
unsigned char b;
do{
b = sd_spi_receive_byte(drive);
if(timer_expired(timer)){
- kputs("sd_spi_receive_block: timeout\n");
+ kputs("sd_spi_receive_sector: timeout\n");
return false;
}
}while(b == 0xFF);
if(b != 0xFE)
return false; /* failed */
- return sd_spi_receive_to_memory(drive, ptr, length); /* returns true on success */
+ return sd_spi_receive_block(drive, ptr, length); /* returns true on success */
}
static int sd_send_command(uint8_t drive, unsigned char cmd, uint32_t arg)
unsigned char csd[16], n;
uint32_t sectors = 0;
- if(sd_send_command(drive, CMD9, 0) == 0 && sd_spi_receive_block(drive, csd, 16)){
+ if(sd_send_command(drive, CMD9, 0) == 0 && sd_spi_receive_sector(drive, csd, 16)){
if ((csd[0] >> 6) == 1) { /* SDC ver 2.00 */
sectors = ((uint32_t)csd[9] + (uint32_t)((unsigned int)csd[8] << 8) + 1) << 10;
} else { /* SDC ver 1.XX or MMC*/
lba = lba << 9; /* multiply by 512 to get byte address */
if(sd_send_command(drive, CMD17, lba) == 0)
- r = sd_spi_receive_block(drive, ptr, 512);
+ r = sd_spi_receive_sector(drive, ptr, 512);
sd_spi_release(drive);
}
lba = lba << 9; /* multiply by 512 to get byte address */
if(sd_send_command(drive, CMD24, lba) == 0)
- r = sd_spi_transmit_block(drive, ptr, 512);
+ r = sd_spi_transmit_sector(drive, ptr, 512);
sd_spi_release(drive);
}
/*-----------------------------------------------------------------------*/
/* N8VEM Mark IV Z180 CSI/O SPI SD driver */
/* 2014-12-27 Will Sowerbutts */
+/* 2014-12-29 Optimised for size/speed */
/*-----------------------------------------------------------------------*/
#include <kernel.h>
__sfr __at (MARK4_IO_BASE + 0x09) MARK4_SD;
-/* the CSI/O and SD card send bits in opposite orders, so we need to flip them over */
-static const uint8_t reverse_byte[256] = {
- 0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
- 0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
- 0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
- 0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
- 0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
- 0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
- 0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
- 0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
- 0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1, 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
- 0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
- 0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5, 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
- 0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed, 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
- 0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
- 0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb, 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
- 0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7, 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
- 0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
-};
-
+/* the CSI/O and SD card send the bits of each byte in opposite orders, so we need to flip them over */
+static uint8_t reverse_byte(uint8_t byte) __naked
+{
+ /* code by John Metcalf, from http://www.retroprogramming.com/2014/01/fast-z80-bit-reversal.html */
+ __asm
+ ld hl, #2
+ add hl, sp
+ ld a, (hl)
+reverse_byte_a:
+ ; reverse bits in A
+ ld l,a ; a = 76543210
+ rlca
+ rlca ; a = 54321076
+ xor l
+ and #0xAA
+ xor l ; a = 56341270
+ ld l,a
+ rlca
+ rlca
+ rlca ; a = 41270563
+ rrc l ; l = 05634127
+ xor l
+ and #0x66
+ xor l ; a = 01234567
+ ld l, a ; return value in L
+ ret
+ __endasm;
+ byte; /* squelch compiler warning */
+}
void sd_spi_clock(uint8_t drive, bool go_fast)
{
drive; /* not used */
/* reverse the bits before we busywait */
- byte = reverse_byte[byte];
+ byte = reverse_byte(byte);
/* wait for any current transmit operation to complete */
do{
while(CSIO_CNTR & CSIO_CNTR_RE);
/* read byte */
- return reverse_byte[CSIO_TRDR];
+ return reverse_byte(CSIO_TRDR);
}
-bool sd_spi_receive_to_memory(uint8_t drive, uint8_t *ptr, unsigned int length)
+#if 0
+/* WRS: measured byte transfer time as 16.88us with Z180 @ 36.864MHz */
+bool sd_spi_receive_block(uint8_t drive, uint8_t *ptr, unsigned int length)
{
- unsigned char c;
- drive; /* not used */
-
- /* wait for any current transmit or receive operation to complete */
- do{
- c = CSIO_CNTR;
- }while(c & (CSIO_CNTR_TE | CSIO_CNTR_RE));
-
- while(length){
- /* enable receive operation */
- CSIO_CNTR = c | CSIO_CNTR_RE;
-
- /* wait for receive to complete */
- do{
- c = CSIO_CNTR;
- }while(c & CSIO_CNTR_RE);
-
- /* read byte */
- *ptr = reverse_byte[CSIO_TRDR];
-
- /* next byte */
- ptr++;
- length--;
+ while(length--){
+ *(ptr++) = sd_spi_receive_byte(drive);
}
-
return true;
}
+#else
+/* WRS: measured byte transfer time as approx 5.66us with Z180 @ 36.864MHz,
+ three times faster. Main change is to start the next receive operation
+ as soon as possible and overlap the loop housekeeping with the receive. */
+bool sd_spi_receive_block(uint8_t drive, uint8_t *ptr, unsigned int length) __naked
+{
+ __asm
+waitrx:
+ in0 a, (_CSIO_CNTR) ; wait for any current transmit or receive operation to complete
+ tst a, #0x30
+ jr nz, waitrx
+ set 5, a ; set CSIO_CNTR_RE, enable receive operation for first byte
+ out0 (_CSIO_CNTR), a
+ ld h, a ; stash value for reuse later
+ ; load parameters from the stack
+ ld iy, #3
+ add iy, sp
+ ld e, 0(iy) ; ptr -> DE
+ ld d, 1(iy)
+ ld c, 2(iy) ; count -> BC
+ ld b, 3(iy)
+rxnextbyte:
+ dec bc ; length--
+ ld a, b
+ or c
+ jr nz, waitrx2
+ res 5, h ; final byte: clear CSIO_CNTR_RE bit in H
+waitrx2:
+ ld l, c ; store C temporarily
+ ld c, #_CSIO_CNTR ; load IO port address
+waitrx3:
+ tstio #0x20 ; test bits in IO port (C)
+ jr nz, waitrx3 ; wait for receive to complete
+ in0 a, (_CSIO_TRDR) ; load received byte
+ out0 (_CSIO_CNTR), h ; start next receive (or NOP, if this is the final byte)
+ ld c, l ; restore C
+ ; reverse bits in A
+ ld l,a ; a = 76543210
+ rlca
+ rlca ; a = 54321076
+ xor l
+ and #0xAA
+ xor l ; a = 56341270
+ ld l,a
+ rlca
+ rlca
+ rlca ; a = 41270563
+ rrc l ; l = 05634127
+ xor l
+ and #0x66
+ xor l ; a = 01234567
+ ld (de), a ; store reversed byte value
+ inc de ; ptr++
+ bit 5, h
+ jr nz, rxnextbyte ; go again if not yet done
+ ld l, #1 ; return true
+ ret
+ __endasm;
+ drive; ptr; length; /* squelch compiler warnings */
+}
+#endif
-bool sd_spi_transmit_from_memory(uint8_t drive, uint8_t *ptr, int length)
+#if 0
+/* WRS: measured byte transfer time as 10.36us with Z180 @ 36.864MHz */
+bool sd_spi_transmit_block(uint8_t drive, uint8_t *ptr, unsigned int length)
{
- unsigned char c, b;
+ register uint8_t c, b, e;
drive; /* not used */
+ e = (CSIO_CNTR & ~CSIO_CNTR_RE) | CSIO_CNTR_TE;
+
while(length){
- b = reverse_byte[*ptr];
+ b = reverse_byte(*ptr);
/* wait for transmit to complete */
do{
/* write the byte and enable transmitter */
CSIO_TRDR = b;
- CSIO_CNTR = c | CSIO_CNTR_TE;
+ CSIO_CNTR = e;
/* next byte */
ptr++;
}
return true;
}
+#else
+/* WRS: measured byte transfer time as 5.64us with Z180 @ 36.864MHz */
+bool sd_spi_transmit_block(uint8_t drive, uint8_t *ptr, unsigned int length) __naked
+{
+ __asm
+ ; load parameters from the stack
+ ld iy, #3
+ add iy, sp
+ ld e, 0(iy) ; ptr -> DE
+ ld d, 1(iy)
+ ld l, 2(iy) ; count -> HL
+ ld h, 3(iy)
+ in0 a, (_CSIO_CNTR)
+ and #0xDF ; mask off RE bit
+ or #0x10 ; set TE bit
+ ld b, a ; B now contains CNTR register value to start transmission
+txnextbyte:
+ ld a, (de)
+ ; reverse bits in A
+ ld c,a
+ rlca
+ rlca
+ xor c
+ and #0xAA
+ xor c
+ ld c,a
+ rlca
+ rlca
+ rlca
+ rrc c
+ xor c
+ and #0x66
+ xor c
+ ld c, #_CSIO_CNTR ; load IO port address
+waittx:
+ tstio #0x10 ; test bits in IO port (C)
+ jr nz, waittx ; wait for transmit to complete
+ out0 (_CSIO_TRDR), a ; write byte to transmit
+ out0 (_CSIO_CNTR), b ; start transmit
+ inc de ; ptr++
+ dec hl ; length--
+ ld a, h
+ or l
+ jr nz, txnextbyte ; length != 0, go again
+ ld l, #1 ; return true
+ ret
+ __endasm;
+ drive; ptr; length; /* squelch compiler warnings */
+}
+#endif
public / FUZIX.git / commitdiff