[PATCH] dmaengine: DW DMAC: split pdata to hardware properties and platform quirks

[Eugeniy Paltsev]

This patch is to address a proposal by Andy in this thread:
http://www.spinics.net/lists/dmaengine/msg10754.html
Split platform data to actual hardware properties, and platform quirks.
Now we able to use quirks and hardware properties separately from
different sources (pdata, device tree or autoconfig registers)

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
---
 drivers/dma/dw/core.c                | 31 +++++++++++++++-----------
 drivers/dma/dw/platform.c            | 42 +++++++++++++++++++++---------------
 include/linux/platform_data/dma-dw.h | 20 +++++++++++------
 3 files changed, 57 insertions(+), 36 deletions(-)

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index c2c0a61..9352735 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -1451,10 +1451,25 @@ int dw_dma_probe(struct dw_dma_chip *chip)
 
 	dw->regs = chip->regs;
 	chip->dw = dw;
+	/* Reassign the platform data pointer */
+	pdata = dw->pdata;
 
 	pm_runtime_get_sync(chip->dev);
 
-	if (!chip->pdata) {
+	if ((!chip->pdata) ||
+	   (chip->pdata && test_bit(QUIRKS_ONLY_USED, &chip->pdata->quirks))) {
+
+		/*
+		 * Fill quirks with the default values in case of pdata absence
+		 */
+		if (!chip->pdata) {
+			set_bit(QUIRKS_IS_PRIVATE, &pdata->quirks);
+			set_bit(QUIRKS_IS_MEMCPY, &pdata->quirks);
+			set_bit(QUIRKS_IS_NOLLP, &pdata->quirks);
+		} else {
+			pdata->quirks = chip->pdata->quirks;
+		}
+
 		dw_params = dma_readl(dw, DW_PARAMS);
 		dev_dbg(chip->dev, "DW_PARAMS: 0x%08x\n", dw_params);
 
@@ -1464,9 +1479,6 @@ int dw_dma_probe(struct dw_dma_chip *chip)
 			goto err_pdata;
 		}
 
-		/* Reassign the platform data pointer */
-		pdata = dw->pdata;
-
 		/* Get hardware configuration parameters */
 		pdata->nr_channels = (dw_params >> DW_PARAMS_NR_CHAN & 7) + 1;
 		pdata->nr_masters = (dw_params >> DW_PARAMS_NR_MASTER & 3) + 1;
@@ -1477,8 +1489,6 @@ int dw_dma_probe(struct dw_dma_chip *chip)
 		pdata->block_size = dma_readl(dw, MAX_BLK_SIZE);
 
 		/* Fill platform data with the default values */
-		pdata->is_private = true;
-		pdata->is_memcpy = true;
 		pdata->chan_allocation_order = CHAN_ALLOCATION_ASCENDING;
 		pdata->chan_priority = CHAN_PRIORITY_ASCENDING;
 	} else if (chip->pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS) {
@@ -1486,9 +1496,6 @@ int dw_dma_probe(struct dw_dma_chip *chip)
 		goto err_pdata;
 	} else {
 		memcpy(dw->pdata, chip->pdata, sizeof(*dw->pdata));
-
-		/* Reassign the platform data pointer */
-		pdata = dw->pdata;
 	}
 
 	dw->chan = devm_kcalloc(chip->dev, pdata->nr_channels, sizeof(*dw->chan),
@@ -1569,7 +1576,7 @@ int dw_dma_probe(struct dw_dma_chip *chip)
 				(dwc_params >> DWC_PARAMS_MBLK_EN & 0x1) == 0;
 		} else {
 			dwc->block_size = pdata->block_size;
-			dwc->nollp = pdata->is_nollp;
+			dwc->nollp = test_bit(QUIRKS_IS_NOLLP, &pdata->quirks);
 		}
 	}
 
@@ -1582,9 +1589,9 @@ int dw_dma_probe(struct dw_dma_chip *chip)
 
 	/* Set capabilities */
 	dma_cap_set(DMA_SLAVE, dw->dma.cap_mask);
-	if (pdata->is_private)
+	if (test_bit(QUIRKS_IS_PRIVATE, &pdata->quirks))
 		dma_cap_set(DMA_PRIVATE, dw->dma.cap_mask);
-	if (pdata->is_memcpy)
+	if (test_bit(QUIRKS_IS_MEMCPY, &pdata->quirks))
 		dma_cap_set(DMA_MEMCPY, dw->dma.cap_mask);
 
 	dw->dma.dev = chip->dev;
diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
index 5bda0eb..308b977 100644
--- a/drivers/dma/dw/platform.c
+++ b/drivers/dma/dw/platform.c
@@ -12,6 +12,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/bitops.h>
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/clk.h>
@@ -111,41 +112,48 @@ dw_dma_parse_dt(struct platform_device *pdev)
 		return NULL;
 	}
 
-	if (of_property_read_u32(np, "dma-masters", &nr_masters))
-		return NULL;
-	if (nr_masters < 1 || nr_masters > DW_DMA_MAX_NR_MASTERS)
-		return NULL;
-
-	if (of_property_read_u32(np, "dma-channels", &nr_channels))
-		return NULL;
-
 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
 		return NULL;
 
+	set_bit(QUIRKS_ONLY_USED, &pdata->quirks);
+
+	if (of_property_read_bool(np, "is-private"))
+		set_bit(QUIRKS_IS_PRIVATE, &pdata->quirks);
+
+	if (of_property_read_bool(np, "is-memcpy"))
+		set_bit(QUIRKS_IS_MEMCPY, &pdata->quirks);
+
+	if (of_property_read_bool(np, "is-nollp"))
+		set_bit(QUIRKS_IS_NOLLP, &pdata->quirks);
+
+	if (of_property_read_u32(np, "dma-masters", &nr_masters))
+		return pdata;
+	if (nr_masters < 1 || nr_masters > DW_DMA_MAX_NR_MASTERS)
+		return pdata;
+
 	pdata->nr_masters = nr_masters;
-	pdata->nr_channels = nr_channels;
 
-	if (of_property_read_bool(np, "is_private"))
-		pdata->is_private = true;
+	if (of_property_read_u32(np, "dma-channels", &nr_channels))
+		return pdata;
 
-	if (!of_property_read_u32(np, "chan_allocation_order", &tmp))
+	pdata->nr_channels = nr_channels;
+
+	if (!of_property_read_u32(np, "chan-allocation-order", &tmp))
 		pdata->chan_allocation_order = (unsigned char)tmp;
 
-	if (!of_property_read_u32(np, "chan_priority", &tmp))
+	if (!of_property_read_u32(np, "chan-priority", &tmp))
 		pdata->chan_priority = tmp;
 
-	if (!of_property_read_u32(np, "block_size", &tmp))
+	if (!of_property_read_u32(np, "block-size", &tmp))
 		pdata->block_size = tmp;
 
 	if (!of_property_read_u32_array(np, "data-width", arr, nr_masters)) {
 		for (tmp = 0; tmp < nr_masters; tmp++)
 			pdata->data_width[tmp] = arr[tmp];
-	} else if (!of_property_read_u32_array(np, "data_width", arr, nr_masters)) {
-		for (tmp = 0; tmp < nr_masters; tmp++)
-			pdata->data_width[tmp] = BIT(arr[tmp] & 0x07);
 	}
 
+	clear_bit(QUIRKS_ONLY_USED, &pdata->quirks);
 	return pdata;
 }
 #else
diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h
index 5f0e11e..9cd8199 100644
--- a/include/linux/platform_data/dma-dw.h
+++ b/include/linux/platform_data/dma-dw.h
@@ -37,10 +37,7 @@ struct dw_dma_slave {
 /**
  * struct dw_dma_platform_data - Controller configuration parameters
  * @nr_channels: Number of channels supported by hardware (max 8)
- * @is_private: The device channels should be marked as private and not for
- *	by the general purpose DMA channel allocator.
- * @is_memcpy: The device channels do support memory-to-memory transfers.
- * @is_nollp: The device channels does not support multi block transfers.
+ * @quirks: Bit field with platform quirks
  * @chan_allocation_order: Allocate channels starting from 0 or 7
  * @chan_priority: Set channel priority increasing from 0 to 7 or 7 to 0.
  * @block_size: Maximum block size supported by the controller
@@ -50,9 +47,18 @@ struct dw_dma_slave {
  */
 struct dw_dma_platform_data {
 	unsigned int	nr_channels;
-	bool		is_private;
-	bool		is_memcpy;
-	bool		is_nollp;
+/* Only use quirks from platform data structure */
+#define QUIRKS_ONLY_USED	0
+/*
+ * The device channels should be marked as private and not for
+ * by the general purpose DMA channel allocator.
+ */
+#define QUIRKS_IS_PRIVATE	1
+/* The device channels do support memory-to-memory transfers. */
+#define QUIRKS_IS_MEMCPY	2
+/* The device channels do not support multi block transfers. */
+#define QUIRKS_IS_NOLLP		3
+	unsigned long	quirks;
 #define CHAN_ALLOCATION_ASCENDING	0	/* zero to seven */
 #define CHAN_ALLOCATION_DESCENDING	1	/* seven to zero */
 	unsigned char	chan_allocation_order;
-- 
2.5.5