+/* --------------------- Cyclic DMA API extensions -------------------- */
+
+/**
+ * dw_dma_cyclic_start - start the cyclic DMA transfer
+ * @chan: the DMA channel to start
+ *
+ * Must be called with soft interrupts disabled. Returns zero on success or
+ * -errno on failure.
+ */
+int dw_dma_cyclic_start(struct dma_chan *chan)
+{
+ struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+ struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+
+ if (!test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) {
+ dev_err(chan2dev(&dwc->chan), "missing prep for cyclic DMA\n");
+ return -ENODEV;
+ }
+
+ spin_lock(&dwc->lock);
+
+ /* assert channel is idle */
+ if (dma_readl(dw, CH_EN) & dwc->mask) {
+ dev_err(chan2dev(&dwc->chan),
+ "BUG: Attempted to start non-idle channel\n");
+ dev_err(chan2dev(&dwc->chan),
+ " SAR: 0x%x DAR: 0x%x LLP: 0x%x CTL: 0x%x:%08x\n",
+ channel_readl(dwc, SAR),
+ channel_readl(dwc, DAR),
+ channel_readl(dwc, LLP),
+ channel_readl(dwc, CTL_HI),
+ channel_readl(dwc, CTL_LO));
+ spin_unlock(&dwc->lock);
+ return -EBUSY;
+ }
+
+ dma_writel(dw, CLEAR.BLOCK, dwc->mask);
+ dma_writel(dw, CLEAR.ERROR, dwc->mask);
+ dma_writel(dw, CLEAR.XFER, dwc->mask);
+
+ /* setup DMAC channel registers */
+ channel_writel(dwc, LLP, dwc->cdesc->desc[0]->txd.phys);
+ channel_writel(dwc, CTL_LO, DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN);
+ channel_writel(dwc, CTL_HI, 0);
+
+ channel_set_bit(dw, CH_EN, dwc->mask);
+
+ spin_unlock(&dwc->lock);
+
+ return 0;
+}
+EXPORT_SYMBOL(dw_dma_cyclic_start);
+
+/**
+ * dw_dma_cyclic_stop - stop the cyclic DMA transfer
+ * @chan: the DMA channel to stop
+ *
+ * Must be called with soft interrupts disabled.
+ */
+void dw_dma_cyclic_stop(struct dma_chan *chan)
+{
+ struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+ struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+
+ spin_lock(&dwc->lock);
+
+ channel_clear_bit(dw, CH_EN, dwc->mask);
+ while (dma_readl(dw, CH_EN) & dwc->mask)
+ cpu_relax();
+
+ spin_unlock(&dwc->lock);
+}
+EXPORT_SYMBOL(dw_dma_cyclic_stop);
+
+/**
+ * dw_dma_cyclic_prep - prepare the cyclic DMA transfer
+ * @chan: the DMA channel to prepare
+ * @buf_addr: physical DMA address where the buffer starts
+ * @buf_len: total number of bytes for the entire buffer
+ * @period_len: number of bytes for each period
+ * @direction: transfer direction, to or from device
+ *
+ * Must be called before trying to start the transfer. Returns a valid struct
+ * dw_cyclic_desc if successful or an ERR_PTR(-errno) if not successful.
+ */
+struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan,
+ dma_addr_t buf_addr, size_t buf_len, size_t period_len,
+ enum dma_data_direction direction)
+{
+ struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+ struct dw_cyclic_desc *cdesc;
+ struct dw_cyclic_desc *retval = NULL;
+ struct dw_desc *desc;
+ struct dw_desc *last = NULL;
+ struct dw_dma_slave *dws = chan->private;
+ unsigned long was_cyclic;
+ unsigned int reg_width;
+ unsigned int periods;
+ unsigned int i;
+
+ spin_lock_bh(&dwc->lock);
+ if (!list_empty(&dwc->queue) || !list_empty(&dwc->active_list)) {
+ spin_unlock_bh(&dwc->lock);
+ dev_dbg(chan2dev(&dwc->chan),
+ "queue and/or active list are not empty\n");
+ return ERR_PTR(-EBUSY);
+ }
+
+ was_cyclic = test_and_set_bit(DW_DMA_IS_CYCLIC, &dwc->flags);
+ spin_unlock_bh(&dwc->lock);
+ if (was_cyclic) {
+ dev_dbg(chan2dev(&dwc->chan),
+ "channel already prepared for cyclic DMA\n");
+ return ERR_PTR(-EBUSY);
+ }
+
+ retval = ERR_PTR(-EINVAL);
+ reg_width = dws->reg_width;
+ periods = buf_len / period_len;
+
+ /* Check for too big/unaligned periods and unaligned DMA buffer. */
+ if (period_len > (DWC_MAX_COUNT << reg_width))
+ goto out_err;
+ if (unlikely(period_len & ((1 << reg_width) - 1)))
+ goto out_err;
+ if (unlikely(buf_addr & ((1 << reg_width) - 1)))
+ goto out_err;
+ if (unlikely(!(direction & (DMA_TO_DEVICE | DMA_FROM_DEVICE))))
+ goto out_err;
+
+ retval = ERR_PTR(-ENOMEM);
+
+ if (periods > NR_DESCS_PER_CHANNEL)
+ goto out_err;
+
+ cdesc = kzalloc(sizeof(struct dw_cyclic_desc), GFP_KERNEL);
+ if (!cdesc)
+ goto out_err;
+
+ cdesc->desc = kzalloc(sizeof(struct dw_desc *) * periods, GFP_KERNEL);
+ if (!cdesc->desc)
+ goto out_err_alloc;
+
+ for (i = 0; i < periods; i++) {
+ desc = dwc_desc_get(dwc);
+ if (!desc)
+ goto out_err_desc_get;
+
+ switch (direction) {
+ case DMA_TO_DEVICE:
+ desc->lli.dar = dws->tx_reg;
+ desc->lli.sar = buf_addr + (period_len * i);
+ desc->lli.ctllo = (DWC_DEFAULT_CTLLO
+ | DWC_CTLL_DST_WIDTH(reg_width)
+ | DWC_CTLL_SRC_WIDTH(reg_width)
+ | DWC_CTLL_DST_FIX
+ | DWC_CTLL_SRC_INC
+ | DWC_CTLL_FC_M2P
+ | DWC_CTLL_INT_EN);
+ break;
+ case DMA_FROM_DEVICE:
+ desc->lli.dar = buf_addr + (period_len * i);
+ desc->lli.sar = dws->rx_reg;
+ desc->lli.ctllo = (DWC_DEFAULT_CTLLO
+ | DWC_CTLL_SRC_WIDTH(reg_width)
+ | DWC_CTLL_DST_WIDTH(reg_width)
+ | DWC_CTLL_DST_INC
+ | DWC_CTLL_SRC_FIX
+ | DWC_CTLL_FC_P2M
+ | DWC_CTLL_INT_EN);
+ break;
+ default:
+ break;
+ }
+
+ desc->lli.ctlhi = (period_len >> reg_width);
+ cdesc->desc[i] = desc;
+
+ if (last) {
+ last->lli.llp = desc->txd.phys;
+ dma_sync_single_for_device(chan2parent(chan),
+ last->txd.phys, sizeof(last->lli),
+ DMA_TO_DEVICE);
+ }
+
+ last = desc;
+ }
+
+ /* lets make a cyclic list */
+ last->lli.llp = cdesc->desc[0]->txd.phys;
+ dma_sync_single_for_device(chan2parent(chan), last->txd.phys,
+ sizeof(last->lli), DMA_TO_DEVICE);
+
+ dev_dbg(chan2dev(&dwc->chan), "cyclic prepared buf 0x%08x len %zu "
+ "period %zu periods %d\n", buf_addr, buf_len,
+ period_len, periods);
+
+ cdesc->periods = periods;
+ dwc->cdesc = cdesc;
+
+ return cdesc;
+
+out_err_desc_get:
+ while (i--)
+ dwc_desc_put(dwc, cdesc->desc[i]);
+out_err_alloc:
+ kfree(cdesc);
+out_err:
+ clear_bit(DW_DMA_IS_CYCLIC, &dwc->flags);
+ return (struct dw_cyclic_desc *)retval;
+}
+EXPORT_SYMBOL(dw_dma_cyclic_prep);
+
+/**
+ * dw_dma_cyclic_free - free a prepared cyclic DMA transfer
+ * @chan: the DMA channel to free
+ */
+void dw_dma_cyclic_free(struct dma_chan *chan)
+{
+ struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+ struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+ struct dw_cyclic_desc *cdesc = dwc->cdesc;
+ int i;
+
+ dev_dbg(chan2dev(&dwc->chan), "cyclic free\n");
+
+ if (!cdesc)
+ return;
+
+ spin_lock_bh(&dwc->lock);
+
+ channel_clear_bit(dw, CH_EN, dwc->mask);
+ while (dma_readl(dw, CH_EN) & dwc->mask)
+ cpu_relax();
+
+ dma_writel(dw, CLEAR.BLOCK, dwc->mask);
+ dma_writel(dw, CLEAR.ERROR, dwc->mask);
+ dma_writel(dw, CLEAR.XFER, dwc->mask);
+
+ spin_unlock_bh(&dwc->lock);
+
+ for (i = 0; i < cdesc->periods; i++)
+ dwc_desc_put(dwc, cdesc->desc[i]);
+
+ kfree(cdesc->desc);
+ kfree(cdesc);
+
+ clear_bit(DW_DMA_IS_CYCLIC, &dwc->flags);
+}
+EXPORT_SYMBOL(dw_dma_cyclic_free);
+