On Mon, 2014-03-03 at 00:30 -0600, Andy Gross wrote: > Add the DMA engine driver for the QCOM Bus Access Manager (BAM) DMA controller > found in the MSM 8x74 platforms. > > Each BAM DMA device is associated with a specific on-chip peripheral. Each > channel provides a uni-directional data transfer engine that is capable of > transferring data between the peripheral and system memory (System mode), or > between two peripherals (BAM2BAM). [] trivia: > +static u32 process_channel_irqs(struct bam_device *bdev) > +{ [] > + for (i = 0; i < bdev->num_channels; i++) { > + struct bam_chan *bchan = &bdev->channels[i]; > + if (srcs & BIT(i)) { > + /* clear pipe irq */ > + pipe_stts = readl_relaxed(bdev->regs + > + BAM_P_IRQ_STTS(i)); > + > + writel_relaxed(pipe_stts, bdev->regs + > + BAM_P_IRQ_CLR(i)); > + > + spin_lock_irqsave(&bchan->vc.lock, flags); > + async_desc = bchan->curr_txd; > + > + if (async_desc) { > + async_desc->num_desc -= async_desc->xfer_len; > + async_desc->curr_desc += async_desc->xfer_len; > + bchan->curr_txd = NULL; > + > + /* manage FIFO */ > + bchan->head += async_desc->xfer_len; > + bchan->head %= MAX_DESCRIPTORS; > + > + /* > + * if complete, process cookie. Otherwise > + * push back to front of desc_issued so that > + * it gets restarted by the tasklet > + */ > + if (!async_desc->num_desc) > + vchan_cookie_complete(&async_desc->vd); > + else > + list_add(&async_desc->vd.node, > + &bchan->vc.desc_issued); > + } > + > + spin_unlock_irqrestore(&bchan->vc.lock, flags); > + } > + } This could be written with fewer indents using continue (and maybe faster using ffs too) for (i = 0; i < bdev->num_channels; i++) { struct bam_chan *bchan; if (!(srcs & BIT(i))) continue; bchan = &bdev->channels[i]; /* clear pipe irq */ pipe_stts = readl_relaxed(bdev->regs + BAM_P_IRQ_STTS(i)); writel_relaxed(pipe_stts, bdev->regs + BAM_P_IRQ_CLR(i)); etc... -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html