On Thu, Feb 26, 2015 at 12:43:33PM +0000, Zubair Lutfullah Kakakhel wrote: > +/* Per-channel registers. */ > +#define JZ_DMA_REG_DSA(n) (0x00 + (n) * 0x20) > +#define JZ_DMA_REG_DTA(n) (0x04 + (n) * 0x20) > +#define JZ_DMA_REG_DTC(n) (0x08 + (n) * 0x20) > +#define JZ_DMA_REG_DRT(n) (0x0c + (n) * 0x20) > +#define JZ_DMA_REG_DCS(n) (0x10 + (n) * 0x20) > +#define JZ_DMA_REG_DCM(n) (0x14 + (n) * 0x20) > +#define JZ_DMA_REG_DDA(n) (0x18 + (n) * 0x20) > +#define JZ_DMA_REG_DSD(n) (0x1c + (n) * 0x20) shouldn't this be a macro rather than copy paste n * 0x20 > + > +#define JZ_DMA_DMAC_DMAE BIT(0) > +#define JZ_DMA_DMAC_AR BIT(2) > +#define JZ_DMA_DMAC_HLT BIT(3) > +#define JZ_DMA_DMAC_FMSC BIT(31) > + > +#define JZ_DMA_DRT_AUTO 0x8 not consistent in BIT? > +static struct jz4780_dma_desc *jz4780_dma_desc_alloc( > + struct jz4780_dma_chan *jzchan, unsigned int count, > + enum dma_transaction_type type) > +{ > + struct jz4780_dma_desc *desc; > + > + if (count > JZ_DMA_MAX_DESC) > + return NULL; > + > + desc = kzalloc(sizeof(*desc), GFP_ATOMIC); GFP_NOWAIT pls > + if (!desc) > + return NULL; > + > + desc->desc = dma_pool_alloc(jzchan->desc_pool, GFP_ATOMIC, ditto > +static uint32_t jz4780_dma_width(enum dma_slave_buswidth width) > +{ > + switch (width) { > + case DMA_SLAVE_BUSWIDTH_1_BYTE: > + return JZ_DMA_WIDTH_8_BIT; > + case DMA_SLAVE_BUSWIDTH_2_BYTES: > + return JZ_DMA_WIDTH_16_BIT; these are same as dmaengine defines so should this be: case DMA_SLAVE_BUSWIDTH_1_BYTE: case DMA_SLAVE_BUSWIDTH_2_BYTES: return width; > + default: > + return JZ_DMA_WIDTH_32_BIT; > + } > +} > + > +static uint32_t jz4780_dma_transfer_size(unsigned long val, int *ord) > +{ > + *ord = ffs(val) - 1; > + > + /* 8 byte transfer sizes unsupported so fall back on 4. */ okay falling back is not a good idea, same applies for default in jz4780_dma_width(). The slave dma parameters are match with devices, so programming something which you dont support, falling back or using defaults is not a good idea > + default: > + WARN_ON(1); > + return -1; /* Can never happen. See previous comment */ -1?? what happened to kernel error codes? > + } > +} > + > +static void jz4780_dma_setup_hwdesc(struct jz4780_dma_chan *jzchan, > + struct jz4780_dma_hwdesc *desc, dma_addr_t addr, size_t len) > +{ > + struct dma_slave_config *config = &jzchan->config; > + uint32_t width, maxburst, tsz; > + int ord; > + > + if (config->direction == DMA_MEM_TO_DEV) { this is a wrong idea, use the direction from the prep_ call > +static enum dma_status jz4780_dma_tx_status(struct dma_chan *chan, > + dma_cookie_t cookie, struct dma_tx_state *txstate) > +{ > + struct jz4780_dma_chan *jzchan = to_jz4780_dma_chan(chan); > + struct virt_dma_desc *vdesc; > + enum dma_status status; > + unsigned long flags; > + > + status = dma_cookie_status(chan, cookie, txstate); > + if (status == DMA_COMPLETE) or if the txstate is NULL -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html