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patch #9327: ft245r.c: add TPI support (patches 1-4) 

Submitted by David Mosberger-Tang:

Optimize TPI programming speed by reducing number of USB reads.
Specifically, when writing to the FTDI chip (without needing the data
it accumulates), simply increment a count of how many bytes the next
read should ignore.  Thus, if there is one or more write followed by a
read, we only need to read from the device once.

Improves TPI programming speed by another factor of 2.



git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk/avrdude@1485 81a1dc3b-b13d-400b-aceb-764788c761c2
This commit is contained in:
Joerg Wunsch 2021-11-24 22:06:31 +00:00
parent 7ff5652edc
commit 105cebb389
2 changed files with 23 additions and 5 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2021-11-24 Joerg Wunsch <j.gnu@uriah.heep.sax.de>
Submitted by David Mosberger-Tang:
patch #9327: ft245r.c: add TPI support (patches 1-4)
* ft245r.c (ft245r_recv): Optimize TPI programming
speed by reducing number of USB reads.
2021-11-24 Joerg Wunsch <j.gnu@uriah.heep.sax.de>
Submitted by David Mosberger-Tang:

21
ft245r.c
View File

@ -161,6 +161,9 @@ static pthread_t readerthread;
static sem_t buf_data, buf_space;
static unsigned char buffer[BUFSIZE];
static int head, tail;
static struct {
int discard; // # of bytes to discard during read
} rx;
static void add_to_buf (unsigned char c) {
int nh;
@ -206,15 +209,24 @@ static int ft245r_send(PROGRAMMER * pgm, unsigned char * buf, size_t len) {
return 0;
}
static int ft245r_send_and_discard(PROGRAMMER * pgm, unsigned char * buf,
size_t len) {
rx.discard += len;
return ft245r_send(pgm, buf, len);
}
static int ft245r_recv(PROGRAMMER * pgm, unsigned char * buf, size_t len) {
int i;
int i = 0;
// Copy over data from the circular buffer..
// XXX This should timeout, and return error if there isn't enough
// data.
for (i=0; i<len; i++) {
while (i < len) {
sem_wait (&buf_data);
buf[i] = buffer[tail];
if (rx.discard > 0)
--rx.discard;
else
buf[i++] = buffer[tail];
if (tail == (BUFSIZE -1)) tail = 0;
else tail++;
sem_post (&buf_space);
@ -645,8 +657,7 @@ static int ft245r_tpi_tx(PROGRAMMER * pgm, uint8_t byte) {
int len;
len = set_tpi_data(pgm, buf, byte);
ft245r_send(pgm, buf, len);
ft245r_recv(pgm, buf, len);
ft245r_send_and_discard(pgm, buf, len);
return 0;
}