[PATCH v2 5/8] dmaengine: dw: introduce block2bytes() and bytes2block()

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

The newly introduced helpers prepare driver to support new DMA controller
hardware.

While here, introduce DWC_CTLH_BLOCK_TS() macro as well.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
 drivers/dma/dw/core.c | 52 ++++++++++++++++++++++++++++++---------------------
 drivers/dma/dw/regs.h |  6 ++++--
 2 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index d5283188605e..8c2af8653520 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -184,6 +184,27 @@ static inline void dwc_chan_disable(struct dw_dma *dw, struct dw_dma_chan *dwc)
 		cpu_relax();
 }
 
+static u32 bytes2block(struct dw_dma_chan *dwc, size_t bytes,
+			  unsigned int width, size_t *len)
+{
+	u32 block;
+
+	if ((bytes >> width) > dwc->block_size) {
+		block = dwc->block_size;
+		*len = block << width;
+	} else {
+		block = bytes >> width;
+		*len = bytes;
+	}
+
+	return block;
+}
+
+static size_t block2bytes(struct dw_dma_chan *dwc, u32 block, u32 width)
+{
+	return DWC_CTLH_BLOCK_TS(block) << width;
+}
+
 /*----------------------------------------------------------------------*/
 
 /* Perform single block transfer */
@@ -332,7 +353,7 @@ static inline u32 dwc_get_sent(struct dw_dma_chan *dwc)
 	u32 ctlhi = channel_readl(dwc, CTL_HI);
 	u32 ctllo = channel_readl(dwc, CTL_LO);
 
-	return (ctlhi & DWC_CTLH_BLOCK_TS_MASK) * (1 << (ctllo >> 4 & 7));
+	return block2bytes(dwc, ctlhi, ctllo >> 4 & 7);
 }
 
 static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
@@ -692,10 +713,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 			| DWC_CTLL_FC_M2M;
 	prev = first = NULL;
 
-	for (offset = 0; offset < len; offset += xfer_count << src_width) {
-		xfer_count = min_t(size_t, (len - offset) >> src_width,
-					   dwc->block_size);
-
+	for (offset = 0; offset < len; offset += xfer_count) {
 		desc = dwc_desc_get(dwc);
 		if (!desc)
 			goto err_desc_get;
@@ -703,8 +721,8 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 		lli_write(desc, sar, src + offset);
 		lli_write(desc, dar, dest + offset);
 		lli_write(desc, ctllo, ctllo);
-		lli_write(desc, ctlhi, xfer_count);
-		desc->len = xfer_count << src_width;
+		lli_write(desc, ctlhi, bytes2block(dwc, len - offset, src_width, &xfer_count));
+		desc->len = xfer_count;
 
 		if (!first) {
 			first = desc;
@@ -775,7 +793,8 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 
 		for_each_sg(sgl, sg, sg_len, i) {
 			struct dw_desc	*desc;
-			u32		len, dlen, mem;
+			u32		len, mem;
+			size_t		dlen;
 
 			mem = sg_dma_address(sg);
 			len = sg_dma_len(sg);
@@ -789,12 +808,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 
 			lli_write(desc, sar, mem);
 			lli_write(desc, dar, reg);
-			if ((len >> mem_width) > dwc->block_size) {
-				dlen = dwc->block_size << mem_width;
-			} else {
-				dlen = len;
-			}
-			lli_write(desc, ctlhi, dlen >> mem_width);
+			lli_write(desc, ctlhi, bytes2block(dwc, len, mem_width, &dlen));
 			lli_write(desc, ctllo, ctllo | DWC_CTLL_SRC_WIDTH(mem_width));
 			desc->len = dlen;
 
@@ -827,7 +841,8 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 
 		for_each_sg(sgl, sg, sg_len, i) {
 			struct dw_desc	*desc;
-			u32		len, dlen, mem;
+			u32		len, mem;
+			size_t		dlen;
 
 			mem = sg_dma_address(sg);
 			len = sg_dma_len(sg);
@@ -839,12 +854,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 
 			lli_write(desc, sar, reg);
 			lli_write(desc, dar, mem);
-			if ((len >> reg_width) > dwc->block_size) {
-				dlen = dwc->block_size << reg_width;
-			} else {
-				dlen = len;
-			}
-			lli_write(desc, ctlhi, dlen >> reg_width);
+			lli_write(desc, ctlhi, bytes2block(dwc, len, reg_width, &dlen));
 			mem_width = __ffs(data_width | mem | dlen);
 			lli_write(desc, ctllo, ctllo | DWC_CTLL_DST_WIDTH(mem_width));
 			desc->len = dlen;
diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h
index 6087eba2c275..ba26d6bce06d 100644
--- a/drivers/dma/dw/regs.h
+++ b/drivers/dma/dw/regs.h
@@ -9,6 +9,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/bitops.h>
 #include <linux/interrupt.h>
 #include <linux/dmaengine.h>
 
@@ -170,8 +171,9 @@ enum dw_dma_msize {
 #define DWC_CTLL_LLP_S_EN	(1 << 28)	/* src block chain */
 
 /* Bitfields in CTL_HI */
-#define DWC_CTLH_DONE		0x00001000
-#define DWC_CTLH_BLOCK_TS_MASK	0x00000fff
+#define DWC_CTLH_BLOCK_TS_MASK	GENMASK(11, 0)
+#define DWC_CTLH_BLOCK_TS(x)	((x) & DWC_CTLH_BLOCK_TS_MASK)
+#define DWC_CTLH_DONE		(1 << 12)
 
 /* Bitfields in CFG_LO */
 #define DWC_CFGL_CH_PRIOR_MASK	(0x7 << 5)	/* priority mask */
-- 
2.11.0

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