On Thu, Mar 27, 2014 at 01:26:27PM +0000, Mark Brown wrote: > On Thu, Mar 27, 2014 at 07:06:59PM +0800, Nicolin Chen wrote: > > It's quite cricial to clear error flags because SAI might hang if getting > > FIFO underrun during playback (I haven't confirmed the same issue on Rx > > overflow though). > > > > So this patch enables those irq and adds isr() to clear the flags so as to > > keep playback entirely safe. > > So, I've applied this since we're (hopefully!) very near the merge > window opening and it seems like it should be an improvement overall. > However a few things below: > > > + /* Only handle those what we enabled */ > > + mask = (FSL_SAI_FLAGS >> FSL_SAI_CSR_xIE_SHIFT) << FSL_SAI_CSR_xF_SHIFT; > > The shifting here could use a comment.
Will send an extra patch to cover it. > > + regmap_update_bits(sai->regmap, FSL_SAI_RCSR, > > + FSL_SAI_CSR_xF_W_MASK | FSL_SAI_CSR_FR, xcsr); > > Using update_bits() is going to do an extra read, better to do this as: > > if (xcsr) > regmap_write(sai->regmap, FSL_SAI_RCSR, xcsr); T/RCSR register stands for T/Rx Control (Status -- I guess) Register. It actually contains control bits, IRQ mask bits and IRQ status bits. Thus we can't regard it as a entire status register. That's why I try to update it partially for status bits only at this point. But if it's just for saving this extra read instance, I may save those non-status bits from upper regmap_read() and then merge them into this regmap_write() over here. > otherwise we might be ignoring any of the bits that are actually clear > on read (it seems like there are some?). For all status flags bits, actually five for each, three of them are write-1-clear and the other two are self-clearance by SAI self -- so none of them are clear-on-read type. > > + return IRQ_HANDLED; > > I'd expect to see IRQ_NONE if we didn't actually see an interrupt > source. Will add this. Thank you, Nicolin _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
