FlapJackApps/libdivecomputer
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Use multipage read commands for faster transfers.

Browse Source 
Multipage read commands can reduce the transfer time significantly,
because the overhead of processing each single page read command is
eliminated.
This commit is contained in:
Jef Driesen 2010-01-22 13:42:03 +00:00
parent 5589770f30
commit 61257a8628
2 changed files with 69 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

59
src/oceanic_veo250.c
View File

@ -32,6 +32,7 @@
#include "checksum.h"
#define MAXRETRIES 2
#define MULTIPAGE 4
#define EXITCODE(rc) \
( \
@ -390,42 +391,52 @@ oceanic_veo250_device_read (device_t *abstract, unsigned int address, unsigned c
unsigned int nbytes = 0;
while (nbytes < size) {
// Calculate the number of packages.
unsigned int npackets = (size - nbytes) / PAGESIZE;
if (npackets > MULTIPAGE)
npackets = MULTIPAGE;
// Read the package.
unsigned int number = address / PAGESIZE;
unsigned char answer[PAGESIZE + 2] = {0};
unsigned int first = address / PAGESIZE;
unsigned int last = first + npackets - 1;
unsigned char answer[(PAGESIZE + 1) * MULTIPAGE + 1] = {0};
unsigned char command[6] = {0x20,
(number ) & 0xFF, // low
(number >> 8) & 0xFF, // high
(number ) & 0xFF, // low
(number >> 8) & 0xFF, // high
(first ) & 0xFF, // low
(first >> 8) & 0xFF, // high
(last ) & 0xFF, // low
(last >> 8) & 0xFF, // high
0};
device_status_t rc = oceanic_veo250_transfer (device, command, sizeof (command), answer, sizeof (answer));
device_status_t rc = oceanic_veo250_transfer (device, command, sizeof (command), answer, (PAGESIZE + 1) * npackets + 1);
if (rc != DEVICE_STATUS_SUCCESS)
return rc;
device->last = number;
device->last = last;
// Verify the checksum of the answer.
unsigned char crc = answer[PAGESIZE];
unsigned char ccrc = checksum_add_uint8 (answer, PAGESIZE, 0x00);
if (crc != ccrc) {
WARNING ("Unexpected answer CRC.");
return DEVICE_STATUS_PROTOCOL;
}
unsigned int offset = 0;
for (unsigned int i = 0; i < npackets; ++i) {
// Verify the checksum of the answer.
unsigned char crc = answer[offset + PAGESIZE];
unsigned char ccrc = checksum_add_uint8 (answer + offset, PAGESIZE, 0x00);
if (crc != ccrc) {
WARNING ("Unexpected answer CRC.");
return DEVICE_STATUS_PROTOCOL;
}
memcpy (data, answer, PAGESIZE);
memcpy (data, answer + offset, PAGESIZE);
#ifndef NDEBUG
message ("VEO250Read(0x%04x,%d)=\"", address, PAGESIZE);
for (unsigned int i = 0; i < PAGESIZE; ++i) {
message("%02x", data[i]);
}
message("\"\n");
message ("VEO250Read(0x%04x,%d)=\"", address, PAGESIZE);
for (unsigned int i = 0; i < PAGESIZE; ++i) {
message("%02x", data[i]);
}
message("\"\n");
#endif
nbytes += PAGESIZE;
address += PAGESIZE;
data += PAGESIZE;
offset += PAGESIZE + 1;
nbytes += PAGESIZE;
address += PAGESIZE;
data += PAGESIZE;
}
}
return DEVICE_STATUS_SUCCESS;

57
src/oceanic_vtpro.c
View File

@ -32,6 +32,7 @@
#include "checksum.h"
#define MAXRETRIES 2
#define MULTIPAGE 4
#define EXITCODE(rc) \
( \
@ -444,40 +445,50 @@ oceanic_vtpro_device_read (device_t *abstract, unsigned int address, unsigned ch
unsigned int nbytes = 0;
while (nbytes < size) {
// Calculate the number of packages.
unsigned int npackets = (size - nbytes) / PAGESIZE;
if (npackets > MULTIPAGE)
npackets = MULTIPAGE;
// Read the package.
unsigned int number = address / PAGESIZE;
unsigned char answer[PAGESIZE + 1] = {0};
unsigned int first = address / PAGESIZE;
unsigned int last = first + npackets - 1;
unsigned char answer[(PAGESIZE + 1) * MULTIPAGE] = {0};
unsigned char command[6] = {0x34,
(number >> 8) & 0xFF, // high
(number ) & 0xFF, // low
(number >> 8) & 0xFF, // high
(number ) & 0xFF, // low
(first >> 8) & 0xFF, // high
(first ) & 0xFF, // low
(last >> 8) & 0xFF, // high
(last ) & 0xFF, // low
0x00};
device_status_t rc = oceanic_vtpro_transfer (device, command, sizeof (command), answer, sizeof (answer));
device_status_t rc = oceanic_vtpro_transfer (device, command, sizeof (command), answer, (PAGESIZE + 1) * npackets);
if (rc != DEVICE_STATUS_SUCCESS)
return rc;
// Verify the checksum of the answer.
unsigned char crc = answer[PAGESIZE];
unsigned char ccrc = checksum_add_uint8 (answer, PAGESIZE, 0x00);
if (crc != ccrc) {
WARNING ("Unexpected answer CRC.");
return DEVICE_STATUS_PROTOCOL;
}
unsigned int offset = 0;
for (unsigned int i = 0; i < npackets; ++i) {
// Verify the checksum of the answer.
unsigned char crc = answer[offset + PAGESIZE];
unsigned char ccrc = checksum_add_uint8 (answer + offset, PAGESIZE, 0x00);
if (crc != ccrc) {
WARNING ("Unexpected answer CRC.");
return DEVICE_STATUS_PROTOCOL;
}
memcpy (data, answer, PAGESIZE);
memcpy (data, answer + offset, PAGESIZE);
#ifndef NDEBUG
message ("VTPRORead(0x%04x,%d)=\"", address, PAGESIZE);
for (unsigned int i = 0; i < PAGESIZE; ++i) {
message("%02x", data[i]);
}
message("\"\n");
message ("VTPRORead(0x%04x,%d)=\"", address, PAGESIZE);
for (unsigned int i = 0; i < PAGESIZE; ++i) {
message("%02x", data[i]);
}
message("\"\n");
#endif
nbytes += PAGESIZE;
address += PAGESIZE;
data += PAGESIZE;
offset += PAGESIZE + 1;
nbytes += PAGESIZE;
address += PAGESIZE;
data += PAGESIZE;
}
}
return DEVICE_STATUS_SUCCESS;