New subject: Add support for WCH CH341A as an SPI programmer.

31 Jan 2016

      On Wed, 27 Jan 2016 03:12:11 +0200
Urja Rannikko <urjaman(a)gmail.com&gt; wrote:

...
  Hi,

 Review-ish... with some only-commentary included too.

 On Mon, Jan 18, 2016 at 1:28 AM, Stefan Tauner
 <stefan.tauner(a)alumni.tuwien.ac.at&gt; wrote:
  Signed-off-by: Urja Rannikko
<urjaman(a)gmail.com&gt;
 Signed-off-by: Stefan Tauner <stefan.tauner(a)alumni.tuwien.ac.at&gt;
 ---
  Makefile        |  23 ++-
  ch341a_spi.c    | 531 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  flashrom.8.tmpl |  12 +-
  flashrom.c      |  12 ++
  programmer.h    |  13 ++
  5 files changed, 588 insertions(+), 3 deletions(-)
  create mode 100644 ch341a_spi.c

 +                       free_idx = (free_idx + 1) % USB_IN_TRANSFERS; /* Increment (and
wrap around). */  Yeah this obvious construct is something I didnt use because
I'm such
 an embedded guy that I'd never ever use % in performance related
 code... (i think i had some if idx>=USB_IN_TRANSFERS) idx = 0
 thing)... thanks for making it saner. 
:)

...
  I had a fancier delay implementation done (all the way
upto ms scale
 using the I2C commands), but since i didnt get that fully tested, this
 one will do, i'll post it as an improvement later. 
Please do. I don't deem it that important but since you have
investigated the whole issue in such detail it would be a waste to not
exploit this knowledge.

...
   +      
unsigned int i;
 +       for (i = 0; i < readcnt; i++) {
 +               /* FIXME: does working on words instead of bytes improve speed? */ 
... drop the comment? i dont really care, but i think our consensus on
 IRC was that a words-wide implementation would have more issues
 (alignment and such) than performance.
 Or make a comment with that info. 
It's gone.

...
   +             
 *readarr++ = swap_byte(rbuf[writecnt + i]);
 +       }
 +
 +       return 0;
 +}
 +
 +static const struct spi_master spi_master_ch341a_spi = {
 +       .type           = SPI_CONTROLLER_CH341A_SPI,
 +       /* TODO: flashrom's current maximum is 256 B. Device was tested on Linux to
accept atleast 16 kB. */
 +       .max_data_read  = 16 * 1024,
 +       .max_data_write = 16 * 1024,  On linux. Not on windows usb
"stack" i think... set these back to 1k?
 Or test for the limit (maybe something like 4k?) and change the 1000ms
 timeout, since i think the big packet would timeout on windows if
 nothing else failed... 
As discussed, I have tested up to 128 kB on Windows (in VM) and on
Linux with a bigger timeout and it works fine. We have agreed upon 4 kB
chunks now and using VLAs (I had an intermediate version that used
bigger chunks and relied on mallocs for them).

...
  With atleast the limits dropped (or tested),  this
is:
 Acked-by: Urja Rannikko <urjaman(a)gmail.com&gt; 
Thanks, r1921.

-- 
Kind regards/Mit freundlichen Grüßen, Stefan Tauner

Re: [flashrom] [PATCH 3/3] Add support for WCH CH341A as an SPI programmer.