#define AT_XDMAC_CC_WRIP (0x1 << 23) /* Write in Progress (read only) */
#define AT_XDMAC_CC_WRIP_DONE (0x0 << 23)
#define AT_XDMAC_CC_WRIP_IN_PROGRESS (0x1 << 23)
-#define AT_XDMAC_CC_PERID(i) (0x7f & (h) << 24) /* Channel Peripheral Identifier */
+#define AT_XDMAC_CC_PERID(i) (0x7f & (i) << 24) /* Channel Peripheral Identifier */
#define AT_XDMAC_CDS_MSP 0x2C /* Channel Data Stride Memory Set Pattern */
#define AT_XDMAC_CSUS 0x30 /* Channel Source Microblock Stride */
#define AT_XDMAC_CDUS 0x34 /* Channel Destination Microblock Stride */
#define AT_XDMAC_MAX_CHAN 0x20
#define AT_XDMAC_MAX_CSIZE 16 /* 16 data */
#define AT_XDMAC_MAX_DWIDTH 8 /* 64 bits */
+#define AT_XDMAC_RESIDUE_MAX_RETRIES 5
#define AT_XDMAC_DMA_BUSWIDTHS\
(BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) |\
NULL,
src_addr, dst_addr,
xt, xt->sgl);
- for (i = 0; i < xt->numf; i++)
+
+ /* Length of the block is (BLEN+1) microblocks. */
+ for (i = 0; i < xt->numf - 1; i++)
at_xdmac_increment_block_count(chan, first);
dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
/* Check remaining length and change data width if needed. */
dwidth = at_xdmac_align_width(chan,
src_addr | dst_addr | xfer_size);
+ chan_cc &= ~AT_XDMAC_CC_DWIDTH_MASK;
chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
ublen = xfer_size >> dwidth;
* since we don't care about the stride anymore.
*/
if ((i == (sg_len - 1)) &&
- sg_dma_len(ppsg) == sg_dma_len(psg)) {
+ sg_dma_len(psg) == sg_dma_len(sg)) {
dev_dbg(chan2dev(chan),
"%s: desc 0x%p can be merged with desc 0x%p\n",
__func__, desc, pdesc);
struct at_xdmac_desc *desc, *_desc;
struct list_head *descs_list;
enum dma_status ret;
- int residue;
- u32 cur_nda, mask, value;
+ int residue, retry;
+ u32 cur_nda, check_nda, cur_ubc, mask, value;
u8 dwidth = 0;
unsigned long flags;
cpu_relax();
}
+ /*
+ * When processing the residue, we need to read two registers but we
+ * can't do it in an atomic way. AT_XDMAC_CNDA is used to find where
+ * we stand in the descriptor list and AT_XDMAC_CUBC is used
+ * to know how many data are remaining for the current descriptor.
+ * Since the dma channel is not paused to not loose data, between the
+ * AT_XDMAC_CNDA and AT_XDMAC_CUBC read, we may have change of
+ * descriptor.
+ * For that reason, after reading AT_XDMAC_CUBC, we check if we are
+ * still using the same descriptor by reading a second time
+ * AT_XDMAC_CNDA. If AT_XDMAC_CNDA has changed, it means we have to
+ * read again AT_XDMAC_CUBC.
+ * Memory barriers are used to ensure the read order of the registers.
+ * A max number of retries is set because unlikely it can never ends if
+ * we are transferring a lot of data with small buffers.
+ */
cur_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
+ rmb();
+ cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC);
+ for (retry = 0; retry < AT_XDMAC_RESIDUE_MAX_RETRIES; retry++) {
+ rmb();
+ check_nda = at_xdmac_chan_read(atchan, AT_XDMAC_CNDA) & 0xfffffffc;
+
+ if (likely(cur_nda == check_nda))
+ break;
+
+ cur_nda = check_nda;
+ rmb();
+ cur_ubc = at_xdmac_chan_read(atchan, AT_XDMAC_CUBC);
+ }
+
+ if (unlikely(retry >= AT_XDMAC_RESIDUE_MAX_RETRIES)) {
+ ret = DMA_ERROR;
+ goto spin_unlock;
+ }
+
/*
* Remove size of all microblocks already transferred and the current
* one. Then add the remaining size to transfer of the current
if ((desc->lld.mbr_nda & 0xfffffffc) == cur_nda)
break;
}
- residue += at_xdmac_chan_read(atchan, AT_XDMAC_CUBC) << dwidth;
+ residue += cur_ubc << dwidth;
dma_set_residue(txstate, residue);
list_for_each_entry_safe(desc, _desc, &atchan->xfers_list, xfer_node)
at_xdmac_remove_xfer(atchan, desc);
+ clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
clear_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
spin_unlock_irqrestore(&atchan->lock, flags);
atchan = to_at_xdmac_chan(chan);
at_xdmac_chan_write(atchan, AT_XDMAC_CC, atchan->save_cc);
if (at_xdmac_chan_is_cyclic(atchan)) {
+ if (at_xdmac_chan_is_paused(atchan))
+ at_xdmac_device_resume(chan);
at_xdmac_chan_write(atchan, AT_XDMAC_CNDA, atchan->save_cnda);
at_xdmac_chan_write(atchan, AT_XDMAC_CNDC, atchan->save_cndc);
at_xdmac_chan_write(atchan, AT_XDMAC_CIE, atchan->save_cim);