Hi
>
> > +static unsigned char reverse_bits(unsigned char num) {
> > + unsigned int count = sizeof(num) * 8 - 1;
> > + unsigned int reverse_num = num;
> > +
> > + num >>= 1;
> > + while (num) {
> > + reverse_num <<= 1;
> > + reverse_num |= num & 1;
> > + num >>= 1;
> > + count--;
> > + }
> > + reverse_num <<= count;
> > + return reverse_num;
> > +}
>
> I can't help but think there ought to be a helper for this though I can't
> think what it is off the top of my head. If there isn't it probably makes
> sense to add this as one.
It seems bitrev8 is doing what I want.
>
> > + /* Enable xfer state machine */
> > + if (!cdns_xspi->xfer_in_progress) {
> > + u32 xfer_control = readl(cdns_xspi->xferbase +
> > +MRVL_XFER_FUNC_CTRL);
> > +
> > + cdns_xspi->current_xfer_qword = 0;
> > + cdns_xspi->xfer_in_progress = true;
> > + xfer_control |= (MRVL_XFER_RECEIVE_ENABLE |
> > + MRVL_XFER_CLK_CAPTURE_POL |
> > + MRVL_XFER_FUNC_START |
> > + MRVL_XFER_SOFT_RESET |
> > + FIELD_PREP(MRVL_XFER_CS_N_HOLD, (1 << cs)));
> > + xfer_control &= ~(MRVL_XFER_FUNC_ENABLE |
> MRVL_XFER_CLK_DRIVE_POL);
> > + writel(xfer_control, cdns_xspi->xferbase +
> MRVL_XFER_FUNC_CTRL);
> > + }
>
> Could this just be a prepare_transfer_hardware() and we could just use
> transfer_one()?
I have run some experiments, and it won't be possible. HW expects reset after
completing whole transfer. With prepare_transfer_hardware() and unprepared_transfer_hardware(),
that reset won't be guaranteed.
Also, there will be a problem when CS line will be changed(without overlay reinit)
Regards
Witek
