On 8 November 2012 03:41, Robert Jarzmik <robert.jarzmik@xxxxxxx> wrote:
> Antony Pavlov <antonynpavlov@xxxxxxxxx> writes:
>
>> apply this commit after that one:
>>
>> Author: Robert Jarzmik <robert.jarzmik@xxxxxxx>
>> Date: Sun Nov 4 18:55:23 2012 +0100
>>
>> commands: change Y-Modem implementation
>> ---
>> lib/xymodem.c | 13 +++++++------
>> 1 file changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/lib/xymodem.c b/lib/xymodem.c
>> index 1469a9a..0e82ce2 100644
>> --- a/lib/xymodem.c
>> +++ b/lib/xymodem.c
>> @@ -257,8 +257,8 @@ static ssize_t xy_read_block(struct xyz_ctxt *proto, struct xy_block *blk,
>> uint64_t timeout)
>> {
>> ssize_t rc, data_len = 0;
>> - unsigned char hdr, seqs[2], crcs[2];
>> - int crc = 0, hdr_found = 0;
>> + unsigned char hdr, seqs[2];
>> + uint16_t crc = 0, hdr_found = 0;
>> uint64_t start = get_time_ns();
>>
>> while (!hdr_found) {
>> @@ -308,12 +308,13 @@ static ssize_t xy_read_block(struct xyz_ctxt *proto, struct xy_block *blk,
>>
>> switch (proto->crc_mode) {
>> case CRC_ADD8:
>> - rc = xy_gets(proto->cdev, proto->fifo, crcs, 1, timeout);
>> - crc = crcs[0];
>> + rc = xy_gets(proto->cdev, proto->fifo,
>> + (unsigned char *)&crc, 1, timeout);
> This doesn't look good to me.
> In big-endian arch, suppose you read 0xab as the crc.
> In that case, won't crc be equal to 0xab00 instead of 0x00ab in this code ? If
> that's the case, the previous code was right ...
To make the patch I got your old working version and your PATCH v2
branches. I got 'git diff'. I found the key difference and tested the
patch. That is all.
May be the 'proto->crc_mode==CRC_ADD8' condition is always false
during my tests?
>> break;
>> case CRC_CRC16:
>> - rc = xy_gets(proto->cdev, proto->fifo, crcs, 2, timeout);
>> - crc = be16_to_cpu(*(uint16_t *)crcs);
>> + rc = xy_gets(proto->cdev, proto->fifo,
>> + (unsigned char *)&crc, 2, timeout);
>> + crc = be16_to_cpu(crc);
>
> Does that mean that the code up there doesn't work on big endian ? I'm really
> puzzled, as the sender sends in big endian, the xy_gets() receives the bytes
> into crcs[2], and the be16_to_cpu() should be a no-op ...
I have no idea just now. I'll try to disassemble generated code.
> I think that we should do this simpler :
> crc = crcs[0] << 8 + crcs[1]
>
> I'll put that into my github branch for testing.
--
Best regards,
Antony Pavlov
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