On Tue, May 10, 2022 at 12:29:54PM +0100, Conor Dooley wrote:
> On 09/05/2022 19:56, Conor Dooley wrote:
> > On 09/05/2022 18:16, Ivan Bornyakov wrote:
> > > On Mon, May 09, 2022 at 11:41:18AM +0000, Conor.Dooley@xxxxxxxxxxxxx wrote:
> > > > Hey Ivan, one comment below.
> > > > Thanks,
> > > > Conor.
> > > >
> > > > On 07/05/2022 08:43, Ivan Bornyakov wrote:
> > > > > ... snip ...
> > > > > +static int mpf_read_status(struct spi_device *spi)
> > > > > +{
> > > > > + u8 status, status_command = MPF_SPI_READ_STATUS;
> > > > > + struct spi_transfer xfer = {
> > > > > + .tx_buf = &status_command,
> > > > > + .rx_buf = &status,
> > > > > + .len = 1,
> > > > > + };
> > > > > + int ret = spi_sync_transfer(spi, &xfer, 1);
> > > > > +
> > > > > + if ((status & MPF_STATUS_SPI_VIOLATION) ||
> > > > > + (status & MPF_STATUS_SPI_ERROR))
> > > > > + ret = -EIO;
> > > > > +
> > > > > + return ret ? : status;
> > > > > +}
> > > > > +
> > > > > ... snip ...
> > > > > +
> > > > > +static int poll_status_not_busy(struct spi_device *spi, u8 mask)
> > > > > +{
> > > > > + int status, timeout = MPF_STATUS_POLL_TIMEOUT;
> > > > > +
> > > > > + while (timeout--) {
> > > > > + status = mpf_read_status(spi);
> > > > > + if (status < 0 ||
> > > > > + (!(status & MPF_STATUS_BUSY) && (!mask || (status & mask))))
> > > > > + return status;
> > > > > +
> > > > > + usleep_range(1000, 2000);
> > > > > + }
> > > > > +
> > > > > + return -EBUSY;
> > > > > +}
> > > >
> > > > Is there a reason you changed this from the snippet you sent me
> > > > in the responses to version 8:
> > > > static int poll_status_not_busy(struct spi_device *spi, u8 mask)
> > > > {
> > > > u8 status, status_command = MPF_SPI_READ_STATUS;
> > > > int ret, timeout = MPF_STATUS_POLL_TIMEOUT;
> > > > struct spi_transfer xfer = {
> > > > .tx_buf = &status_command,
> > > > .rx_buf = &status,
> > > > .len = 1,
> > > > };
> > > >
> > > > while (timeout--) {
> > > > ret = spi_sync_transfer(spi, &xfer, 1);
> > > > if (ret < 0)
> > > > return ret;
> > > >
> > > > if (!(status & MPF_STATUS_BUSY) && (!mask || (status & mask)))
> > > > return status;
> > > >
> > > > usleep_range(1000, 2000);
> > > > }
> > > >
> > > > return -EBUSY;
> > > > }
> > > >
> > > > With the current version, I hit the "Failed to write bitstream
> > > > frame" check in mpf_ops_write at random points in the transfer.
> > > > Replacing poll_status_not_busy with the above allows it to run
> > > > to completion.
> > >
> > > In my eyes they are equivalent, aren't they?
> > >
> >
> > I was in a bit of a rush today & didn't have time to do proper
> > debugging, I'll put some debug code in tomorrow and try to find
> > exactly what is different between the two.
> >
> > Off the top of my head, since I don't have a board on me to test,
> > the only difference I can see is that with the snippet you only
> > checked if spi_sync_transfer was negative whereas now you check
> > if it has a value at all w/ that ternary operator.
> >
> > But even that seems like it *shouldn't* be the problem, since ret
> > should contain -errno or zero, right?
> > Either way, I will do some digging tomorrow.
>
> I put a printk("status %x, ret %d", status, ret); into the failure
> path of mpf_read_status() & it looks like a status 0xA is being
> returned - error & ready? That seems like a very odd combo to be
> getting back out of it. It shouldn't be dodgy driver/connection
> either, b/c that's what I see if I connect my protocol analyser:
> https://i.imgur.com/VbjgfCk.png
>
> That's mosi (hex), ss, sclk, mosi, miso (hex), miso in descending
> order.
>
> I think what was happening was with the snippet you returned one
> of the following: -EBUSY, ret (aka -errno) or status. Since status
> is positive, the checks in mpf_spi_write.*() saw nothing wrong at
> all and programming continued despite there being a problem.
>
> The new version fixes this by returning -EIO rather than status from
> poll_status_not_busy().
>
> I wish I had a socketable PolarFire so I could investigate further,
> but this looks like it might a be hardware issue somewhere on my
> end?
>
> So ye, sorry for the noise and carry on! I'll try tofind what is to
> blame for it.
>
> Thanks,
> Conor.
>
Hi, Conor.
I've just noticed in SPI-DirectC User Guide [1] ch. 9 SmartFusion2 and
IGLOO2 SPI-Slave Programming Waveform Analysis, that hw status checked
two times every time. Does MPF family also need double check hw status?
Does adding second mpf_read_status() to poll_status_not_busy() routine
help with your issue?
