On Thursday 13 November 2014 12:58:08 Andrew Bresticker wrote:
> +
> +static bool mdc_filter_fn(struct dma_chan *chan, void *fn_param)
> +{
> + struct mdc_filter_data *data = fn_param;
> + struct mdc_chan *mchan;
> +
> + if (chan->device->dev->driver == &mdc_dma_driver.driver) {
> + mchan = to_mdc_chan(chan);
> + if (!(data->mask & BIT(mchan->chan_nr)))
> + return false;
> + mchan->periph = data->periph;
> + mchan->thread = data->thread;
> + return true;
> + }
> + return false;
> +}
> +
> +static struct dma_chan *mdc_of_xlate(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma)
> +{
> + struct mdc_dma *mdma = ofdma->of_dma_data;
> + struct mdc_filter_data data;
> +
> + if (dma_spec->args_count != 3)
> + return NULL;
> +
> + data.periph = dma_spec->args[0];
> + data.mask = dma_spec->args[1];
> + data.thread = dma_spec->args[2];
> +
> + return dma_request_channel(mdma->dma_dev.cap_mask, mdc_filter_fn,
> + &data);
> +}
The filter function is broken if you ever have multiple instances
of the device. Better avoid calling dma_request_channel and scan
the channels that the device knows about.
> +
> +#define PISTACHIO_CR_PERIPH_DMA_ROUTE(ch) (0x120 + 0x4 * ((ch) / 4))
> +#define PISTACHIO_CR_PERIPH_DMA_ROUTE_SHIFT(ch) (8 * ((ch) % 4))
> +#define PISTACHIO_CR_PERIPH_DMA_ROUTE_MASK 0x3f
> +
> +static void pistachio_mdc_enable_chan(struct mdc_chan *mchan)
> +{
> + struct mdc_dma *mdma = mchan->mdma;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&mdma->lock, flags);
> + regmap_update_bits(mdma->periph_regs,
> + PISTACHIO_CR_PERIPH_DMA_ROUTE(mchan->chan_nr),
> + PISTACHIO_CR_PERIPH_DMA_ROUTE_MASK <<
> + PISTACHIO_CR_PERIPH_DMA_ROUTE_SHIFT(mchan->chan_nr),
> + mchan->periph <<
> + PISTACHIO_CR_PERIPH_DMA_ROUTE_SHIFT(mchan->chan_nr));
> + spin_unlock_irqrestore(&mdma->lock, flags);
> +}
> +
> +static void pistachio_mdc_disable_chan(struct mdc_chan *mchan)
> +{
> + struct mdc_dma *mdma = mchan->mdma;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&mdma->lock, flags);
> + regmap_update_bits(mdma->periph_regs,
> + PISTACHIO_CR_PERIPH_DMA_ROUTE(mchan->chan_nr),
> + PISTACHIO_CR_PERIPH_DMA_ROUTE_MASK <<
> + PISTACHIO_CR_PERIPH_DMA_ROUTE_SHIFT(mchan->chan_nr),
> + 0);
> + spin_unlock_irqrestore(&mdma->lock, flags);
> +}
Regmap has its own locking, no need to add another level.
Arnd
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