dmaengine: dma40: Add support to split up large elements

The maximum transfer size of the stedma40 is (64k-1) x data-width.
If the transfer size of one element exceeds this limit
the job is split up and sent as linked transfer.
Signed-off-by: Per Forlin <per.forlin@linaro.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

arch/arm/plat-nomadik/include/plat/ste_dma40.h

@@ -13,6 +13,14 @@
 #include <linux/workqueue.h>
 #include <linux/interrupt.h>
 
+/*
+ * Maxium size for a single dma descriptor
+ * Size is limited to 16 bits.
+ * Size is in the units of addr-widths (1,2,4,8 bytes)
+ * Larger transfers will be split up to multiple linked desc
+ */
+#define STEDMA40_MAX_SEG_SIZE 0xFFFF
+
 /* dev types for memcpy */
 #define STEDMA40_DEV_DST_MEMORY (-1)
 #define	STEDMA40_DEV_SRC_MEMORY (-1)

drivers/dma/ste_dma40_ll.c

 /*
  * Copyright (C) ST-Ericsson SA 2007-2010
- * Author: Per Friden <per.friden@stericsson.com> for ST-Ericsson
+ * Author: Per Forlin <per.forlin@stericsson.com> for ST-Ericsson
  * Author: Jonas Aaberg <jonas.aberg@stericsson.com> for ST-Ericsson
  * License terms: GNU General Public License (GPL) version 2
  */
@@ -122,15 +122,15 @@ void d40_phy_cfg(struct stedma40_chan_cfg *cfg,
 	*dst_cfg = dst;
 }
 
-int d40_phy_fill_lli(struct d40_phy_lli *lli,
-		     dma_addr_t data,
-		     u32 data_size,
-		     int psize,
-		     dma_addr_t next_lli,
-		     u32 reg_cfg,
-		     bool term_int,
-		     u32 data_width,
-		     bool is_device)
+static int d40_phy_fill_lli(struct d40_phy_lli *lli,
+			    dma_addr_t data,
+			    u32 data_size,
+			    int psize,
+			    dma_addr_t next_lli,
+			    u32 reg_cfg,
+			    bool term_int,
+			    u32 data_width,
+			    bool is_device)
 {
 	int num_elems;
 
@@ -139,13 +139,6 @@ int d40_phy_fill_lli(struct d40_phy_lli *lli,
 	else
 		num_elems = 2 << psize;
 
-	/*
-	 * Size is 16bit. data_width is 8, 16, 32 or 64 bit
-	 * Block large than 64 KiB must be split.
-	 */
-	if (data_size > (0xffff << data_width))
-		return -EINVAL;
-
 	/* Must be aligned */
 	if (!IS_ALIGNED(data, 0x1 << data_width))
 		return -EINVAL;
@@ -187,55 +180,118 @@ int d40_phy_fill_lli(struct d40_phy_lli *lli,
 	return 0;
 }
 
+static int d40_seg_size(int size, int data_width1, int data_width2)
+{
+	u32 max_w = max(data_width1, data_width2);
+	u32 min_w = min(data_width1, data_width2);
+	u32 seg_max = ALIGN(STEDMA40_MAX_SEG_SIZE << min_w, 1 << max_w);
+
+	if (seg_max > STEDMA40_MAX_SEG_SIZE)
+		seg_max -= (1 << max_w);
+
+	if (size <= seg_max)
+		return size;
+
+	if (size <= 2 * seg_max)
+		return ALIGN(size / 2, 1 << max_w);
+
+	return seg_max;
+}
+
+struct d40_phy_lli *d40_phy_buf_to_lli(struct d40_phy_lli *lli,
+				       dma_addr_t addr,
+				       u32 size,
+				       int psize,
+				       dma_addr_t lli_phys,
+				       u32 reg_cfg,
+				       bool term_int,
+				       u32 data_width1,
+				       u32 data_width2,
+				       bool is_device)
+{
+	int err;
+	dma_addr_t next = lli_phys;
+	int size_rest = size;
+	int size_seg = 0;
+
+	do {
+		size_seg = d40_seg_size(size_rest, data_width1, data_width2);
+		size_rest -= size_seg;
+
+		if (term_int && size_rest == 0)
+			next = 0;
+		else
+			next = ALIGN(next + sizeof(struct d40_phy_lli),
+				     D40_LLI_ALIGN);
+
+		err = d40_phy_fill_lli(lli,
+				       addr,
+				       size_seg,
+				       psize,
+				       next,
+				       reg_cfg,
+				       !next,
+				       data_width1,
+				       is_device);
+
+		if (err)
+			goto err;
+
+		lli++;
+		if (!is_device)
+			addr += size_seg;
+	} while (size_rest);
+
+	return lli;
+
+ err:
+	return NULL;
+}
+
 int d40_phy_sg_to_lli(struct scatterlist *sg,
 		      int sg_len,
 		      dma_addr_t target,
-		      struct d40_phy_lli *lli,
+		      struct d40_phy_lli *lli_sg,
 		      dma_addr_t lli_phys,
 		      u32 reg_cfg,
-		      u32 data_width,
+		      u32 data_width1,
+		      u32 data_width2,
 		      int psize)
 {
 	int total_size = 0;
 	int i;
 	struct scatterlist *current_sg = sg;
-	dma_addr_t next_lli_phys;
 	dma_addr_t dst;
-	int err = 0;
+	struct d40_phy_lli *lli = lli_sg;
+	dma_addr_t l_phys = lli_phys;
 
 	for_each_sg(sg, current_sg, sg_len, i) {
 
 		total_size += sg_dma_len(current_sg);
 
-		/* If this scatter list entry is the last one, no next link */
-		if (sg_len - 1 == i)
-			next_lli_phys = 0;
-		else
-			next_lli_phys = ALIGN(lli_phys + (i + 1) *
-					      sizeof(struct d40_phy_lli),
-					      D40_LLI_ALIGN);
-
 		if (target)
 			dst = target;
 		else
 			dst = sg_phys(current_sg);
 
-		err = d40_phy_fill_lli(&lli[i],
-				       dst,
-				       sg_dma_len(current_sg),
-				       psize,
-				       next_lli_phys,
-				       reg_cfg,
-				       !next_lli_phys,
-				       data_width,
-				       target == dst);
-		if (err)
-			goto err;
+		l_phys = ALIGN(lli_phys + (lli - lli_sg) *
+			       sizeof(struct d40_phy_lli), D40_LLI_ALIGN);
+
+		lli = d40_phy_buf_to_lli(lli,
+					 dst,
+					 sg_dma_len(current_sg),
+					 psize,
+					 l_phys,
+					 reg_cfg,
+					 sg_len - 1 == i,
+					 data_width1,
+					 data_width2,
+					 target == dst);
+		if (lli == NULL)
+			return -EINVAL;
 	}
 
 	return total_size;
-err:
-	return err;
 }
 
 
@@ -315,17 +371,20 @@ void d40_log_lli_lcla_write(struct d40_log_lli *lcla,
 	writel(lli_dst->lcsp13, &lcla[1].lcsp13);
 }
 
-void d40_log_fill_lli(struct d40_log_lli *lli,
-		      dma_addr_t data, u32 data_size,
-		      u32 reg_cfg,
-		      u32 data_width,
-		      bool addr_inc)
+static void d40_log_fill_lli(struct d40_log_lli *lli,
+			     dma_addr_t data, u32 data_size,
+			     u32 reg_cfg,
+			     u32 data_width,
+			     bool addr_inc)
 {
 	lli->lcsp13 = reg_cfg;
 
 	/* The number of elements to transfer */
 	lli->lcsp02 = ((data_size >> data_width) <<
 		       D40_MEM_LCSP0_ECNT_POS) & D40_MEM_LCSP0_ECNT_MASK;
+
+	BUG_ON((data_size >> data_width) > STEDMA40_MAX_SEG_SIZE);
+
 	/* 16 LSBs address of the current element */
 	lli->lcsp02 |= data & D40_MEM_LCSP0_SPTR_MASK;
 	/* 16 MSBs address of the current element */
@@ -348,55 +407,94 @@ int d40_log_sg_to_dev(struct scatterlist *sg,
 	int total_size = 0;
 	struct scatterlist *current_sg = sg;
 	int i;
+	struct d40_log_lli *lli_src = lli->src;
+	struct d40_log_lli *lli_dst = lli->dst;
 
 	for_each_sg(sg, current_sg, sg_len, i) {
 		total_size += sg_dma_len(current_sg);
 
 		if (direction == DMA_TO_DEVICE) {
-			d40_log_fill_lli(&lli->src[i],
-					 sg_phys(current_sg),
-					 sg_dma_len(current_sg),
-					 lcsp->lcsp1, src_data_width,
-					 true);
-			d40_log_fill_lli(&lli->dst[i],
-					 dev_addr,
-					 sg_dma_len(current_sg),
-					 lcsp->lcsp3, dst_data_width,
-					 false);
+			lli_src =
+				d40_log_buf_to_lli(lli_src,
+						   sg_phys(current_sg),
+						   sg_dma_len(current_sg),
+						   lcsp->lcsp1, src_data_width,
+						   dst_data_width,
+						   true);
+			lli_dst =
+				d40_log_buf_to_lli(lli_dst,
+						   dev_addr,
+						   sg_dma_len(current_sg),
+						   lcsp->lcsp3, dst_data_width,
+						   src_data_width,
+						   false);
 		} else {
-			d40_log_fill_lli(&lli->dst[i],
-					 sg_phys(current_sg),
-					 sg_dma_len(current_sg),
-					 lcsp->lcsp3, dst_data_width,
-					 true);
-			d40_log_fill_lli(&lli->src[i],
-					 dev_addr,
-					 sg_dma_len(current_sg),
-					 lcsp->lcsp1, src_data_width,
-					 false);
+			lli_dst =
+				d40_log_buf_to_lli(lli_dst,
+						   sg_phys(current_sg),
+						   sg_dma_len(current_sg),
+						   lcsp->lcsp3, dst_data_width,
+						   src_data_width,
+						   true);
+			lli_src =
+				d40_log_buf_to_lli(lli_src,
+						   dev_addr,
+						   sg_dma_len(current_sg),
+						   lcsp->lcsp1, src_data_width,
+						   dst_data_width,
+						   false);
 		}
 	}
 	return total_size;
 }
 
+struct d40_log_lli *d40_log_buf_to_lli(struct d40_log_lli *lli_sg,
+				       dma_addr_t addr,
+				       int size,
+				       u32 lcsp13, /* src or dst*/
+				       u32 data_width1,
+				       u32 data_width2,
+				       bool addr_inc)
+{
+	struct d40_log_lli *lli = lli_sg;
+	int size_rest = size;
+	int size_seg = 0;
+
+	do {
+		size_seg = d40_seg_size(size_rest, data_width1, data_width2);
+		size_rest -= size_seg;
+
+		d40_log_fill_lli(lli,
+				 addr,
+				 size_seg,
+				 lcsp13, data_width1,
+				 addr_inc);
+		if (addr_inc)
+			addr += size_seg;
+		lli++;
+	} while (size_rest);
+
+	return lli;
+}
+
 int d40_log_sg_to_lli(struct scatterlist *sg,
 		      int sg_len,
 		      struct d40_log_lli *lli_sg,
 		      u32 lcsp13, /* src or dst*/
-		      u32 data_width)
+		      u32 data_width1, u32 data_width2)
 {
 	int total_size = 0;
 	struct scatterlist *current_sg = sg;
 	int i;
+	struct d40_log_lli *lli = lli_sg;
 
 	for_each_sg(sg, current_sg, sg_len, i) {
 		total_size += sg_dma_len(current_sg);
-
-		d40_log_fill_lli(&lli_sg[i],
-				 sg_phys(current_sg),
-				 sg_dma_len(current_sg),
-				 lcsp13, data_width,
-				 true);
+		lli = d40_log_buf_to_lli(lli,
+					 sg_phys(current_sg),
+					 sg_dma_len(current_sg),
+					 lcsp13,
+					 data_width1, data_width2, true);
 	}
 	return total_size;
 }

drivers/dma/ste_dma40_ll.h

@@ -292,18 +292,20 @@ int d40_phy_sg_to_lli(struct scatterlist *sg,
 		      struct d40_phy_lli *lli,
 		      dma_addr_t lli_phys,
 		      u32 reg_cfg,
-		      u32 data_width,
+		      u32 data_width1,
+		      u32 data_width2,
 		      int psize);
 
-int d40_phy_fill_lli(struct d40_phy_lli *lli,
-		     dma_addr_t data,
-		     u32 data_size,
-		     int psize,
-		     dma_addr_t next_lli,
-		     u32 reg_cfg,
-		     bool term_int,
-		     u32 data_width,
-		     bool is_device);
+struct d40_phy_lli *d40_phy_buf_to_lli(struct d40_phy_lli *lli,
+				       dma_addr_t data,
+				       u32 data_size,
+				       int psize,
+				       dma_addr_t next_lli,
+				       u32 reg_cfg,
+				       bool term_int,
+				       u32 data_width1,
+				       u32 data_width2,
+				       bool is_device);
 
 void d40_phy_lli_write(void __iomem *virtbase,
 		       u32 phy_chan_num,
@@ -312,12 +314,12 @@ void d40_phy_lli_write(void __iomem *virtbase,
 
 /* Logical channels */
 
-void d40_log_fill_lli(struct d40_log_lli *lli,
-		      dma_addr_t data,
-		      u32 data_size,
-		      u32 reg_cfg,
-		      u32 data_width,
-		      bool addr_inc);
+struct d40_log_lli *d40_log_buf_to_lli(struct d40_log_lli *lli_sg,
+				       dma_addr_t addr,
+				       int size,
+				       u32 lcsp13, /* src or dst*/
+				       u32 data_width1, u32 data_width2,
+				       bool addr_inc);
 
 int d40_log_sg_to_dev(struct scatterlist *sg,
 		      int sg_len,
@@ -332,7 +334,7 @@ int d40_log_sg_to_lli(struct scatterlist *sg,
 		      int sg_len,
 		      struct d40_log_lli *lli_sg,
 		      u32 lcsp13, /* src or dst*/
-		      u32 data_width);
+		      u32 data_width1, u32 data_width2);
 
 void d40_log_lli_lcpa_write(struct d40_log_lli_full *lcpa,
 			    struct d40_log_lli *lli_dst,