[PATCH v4 1/4] dw_dmac: remove unnecessary tx_list field in dw_dma_chan

Andy Shevchenko
2013-01-25T09:48:39Z

The soft LLP mode is working for active descriptor only. So, we do not need to
have a copy of its pointer.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
---
drivers/dma/dw_dmac.c | 20 +++++++++++++++-----
drivers/dma/dw_dmac_regs.h | 1 -
2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 72e6316..e4e4ff2 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -284,9 +284,9 @@ static void dwc_dostart(struct dw_dma_chan *dwc, struct dw_desc *first)

dwc_initialize(dwc);

- dwc->tx_list = &first->tx_list;
dwc->tx_node_active = &first->tx_list;

+ /* Submit first block */
dwc_do_single_block(dwc, first);

return;
@@ -404,15 +404,25 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
dma_writel(dw, CLEAR.XFER, dwc->mask);

if (test_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags)) {
- if (dwc->tx_node_active != dwc->tx_list) {
- desc = to_dw_desc(dwc->tx_node_active);
+ struct list_head *head, *active = dwc->tx_node_active;
+
+ /*
+ * We are inside first active descriptor.
+ * Otherwise something is really wrong.
+ */
+ desc = dwc_first_active(dwc);
+
+ head = &desc->tx_list;
+ if (active != head) {
+ child = to_dw_desc(active);

/* Submit next block */
- dwc_do_single_block(dwc, desc);
- spin_unlock_irqrestore(&dwc->lock, flags);
+ dwc_do_single_block(dwc, child);

+ spin_unlock_irqrestore(&dwc->lock, flags);
return;
}
+
/* We are done here */
clear_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags);
}
diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index fef296d..13000d2 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -194,7 +194,6 @@ struct dw_dma_chan {
bool initialized;

/* software emulation of the LLP transfers */
- struct list_head *tx_list;
struct list_head *tx_node_active;

spinlock_t lock;
--
1.7.10.4