[PATCH 07/15] dmaengine: dw: revisit data_width property

From: Mans Rullgard
Date: Sun Jan 24 2016 - 14:25:23 EST

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From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

There are several changes are done here:

- Convert the property to be in bytes

Much more convenient than keeping encoded value.

- Use one value for all AHB masters for now

It seems in practice we have no controllers where masters have different
data bus width, we still might return to distinct values when there is a use
case.

- Rename data_width to data-width in the device tree bindings.

- While here, replace dwc_fast_ffs() by __ffs().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Mans Rullgard <mans@xxxxxxxxx>
---
This patch changes the DT binding, so it should probably be amended for
compatibility with old device trees. I've included it as is since I think
the change as such is good.
---
Documentation/devicetree/bindings/dma/snps-dma.txt | 5 ++-
arch/arc/boot/dts/abilis_tb10x.dtsi | 2 +-
arch/arm/boot/dts/spear13xx.dtsi | 4 +--
drivers/dma/dw/core.c | 40 +++-------------------
drivers/dma/dw/platform.c | 8 ++---
drivers/dma/dw/regs.h | 2 +-
include/linux/platform_data/dma-dw.h | 5 ++-
7 files changed, 16 insertions(+), 50 deletions(-)

diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt b/Documentation/devicetree/bindings/dma/snps-dma.txt
index c99c1ffac199..fe7f7710a6b4 100644
--- a/Documentation/devicetree/bindings/dma/snps-dma.txt
+++ b/Documentation/devicetree/bindings/dma/snps-dma.txt
@@ -13,8 +13,7 @@ Required properties:
- chan_priority: priority of channels. 0 (default): increase from chan 0->n, 1:
increase from chan n->0
- block_size: Maximum block size supported by the controller
-- data_width: Maximum data width supported by hardware per AHB master
- (0 - 8bits, 1 - 16bits, ..., 5 - 256bits)
+- data-width: Maximum data width supported by hardware (in bytes)

Optional properties:
@@ -38,7 +37,7 @@ Example:
chan_allocation_order = <1>;
chan_priority = <1>;
block_size = <0xfff>;
- data_width = <3 3>;
+ data-width = <8>;
};

DMA clients connected to the Designware DMA controller must use the format
diff --git a/arch/arc/boot/dts/abilis_tb10x.dtsi b/arch/arc/boot/dts/abilis_tb10x.dtsi
index cfb5052239a1..2f53bedb0cde 100644
--- a/arch/arc/boot/dts/abilis_tb10x.dtsi
+++ b/arch/arc/boot/dts/abilis_tb10x.dtsi
@@ -112,7 +112,7 @@
chan_allocation_order = <0>;
chan_priority = <1>;
block_size = <0x7ff>;
- data_width = <2>;
+ data-width = <4>;
clocks = <&ahb_clk>;
clock-names = "hclk";
};
diff --git a/arch/arm/boot/dts/spear13xx.dtsi b/arch/arm/boot/dts/spear13xx.dtsi
index 14594ce8c18a..474b66fa6a32 100644
--- a/arch/arm/boot/dts/spear13xx.dtsi
+++ b/arch/arm/boot/dts/spear13xx.dtsi
@@ -117,7 +117,7 @@
chan_priority = <1>;
block_size = <0xfff>;
dma-masters = <2>;
- data_width = <3 3>;
+ data-width = <8>;
};

dma@eb000000 {
@@ -133,7 +133,7 @@
chan_allocation_order = <1>;
chan_priority = <1>;
block_size = <0xfff>;
- data_width = <3 3>;
+ data-width = <8>;
};

fsmc: flash@b0000000 {
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 140ea59ec882..28278e4c77ad 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -168,21 +168,6 @@ static void dwc_initialize(struct dw_dma_chan *dwc)

/*----------------------------------------------------------------------*/

-static inline unsigned int dwc_fast_ffs(unsigned long long v)
-{
- /*
- * We can be a lot more clever here, but this should take care
- * of the most common optimization.
- */
- if (!(v & 7))
- return 3;
- else if (!(v & 3))
- return 2;
- else if (!(v & 1))
- return 1;
- return 0;
-}
-
static inline void dwc_dump_chan_regs(struct dw_dma_chan *dwc)
{
dev_err(chan2dev(&dwc->chan),
@@ -712,7 +697,6 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
size_t offset;
unsigned int src_width;
unsigned int dst_width;
- unsigned int data_width;
u32 ctllo;

dev_vdbg(chan2dev(chan),
@@ -726,10 +710,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,

dwc->direction = DMA_MEM_TO_MEM;

- data_width = dw->data_width[dwc->m_master];
-
- src_width = dst_width = min_t(unsigned int, data_width,
- dwc_fast_ffs(src | dest | len));
+ src_width = dst_width = __ffs(dw->data_width | src | dest | len);

ctllo = DWC_DEFAULT_CTLLO(chan)
| DWC_CTLL_DST_WIDTH(dst_width)
@@ -792,7 +773,6 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
dma_addr_t reg;
unsigned int reg_width;
unsigned int mem_width;
- unsigned int data_width;
unsigned int i;
struct scatterlist *sg;
size_t total_len = 0;
@@ -818,8 +798,6 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
DWC_CTLL_FC(DW_DMA_FC_D_M2P);

- data_width = dw->data_width[dwc->m_master];
-
for_each_sg(sgl, sg, sg_len, i) {
struct dw_desc *desc;
u32 len, dlen, mem;
@@ -827,8 +805,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
mem = sg_dma_address(sg);
len = sg_dma_len(sg);

- mem_width = min_t(unsigned int,
- data_width, dwc_fast_ffs(mem | len));
+ mem_width = __ffs(dw->data_width | mem | len);

slave_sg_todev_fill_desc:
desc = dwc_desc_get(dwc);
@@ -874,8 +851,6 @@ slave_sg_todev_fill_desc:
ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
DWC_CTLL_FC(DW_DMA_FC_D_P2M);

- data_width = dw->data_width[dwc->m_master];
-
for_each_sg(sgl, sg, sg_len, i) {
struct dw_desc *desc;
u32 len, dlen, mem;
@@ -883,8 +858,7 @@ slave_sg_todev_fill_desc:
mem = sg_dma_address(sg);
len = sg_dma_len(sg);

- mem_width = min_t(unsigned int,
- data_width, dwc_fast_ffs(mem | len));
+ mem_width = __ffs(dw->data_width | mem | len);

slave_sg_fromdev_fill_desc:
desc = dwc_desc_get(dwc);
@@ -1531,10 +1505,7 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *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;
- for (i = 0; i < pdata->nr_masters; i++) {
- pdata->data_width[i] =
- (dw_params >> DW_PARAMS_DATA_WIDTH(i) & 3) + 2;
- }
+ pdata->data_width = 4 << (dw_params >> DW_PARAMS_DATA_WIDTH(0) & 3);
max_blk_size = dma_readl(dw, MAX_BLK_SIZE);

/* Fill platform data with the default values */
@@ -1556,8 +1527,7 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)

/* Get hardware configuration parameters */
dw->nr_masters = pdata->nr_masters;
- for (i = 0; i < dw->nr_masters; i++)
- dw->data_width[i] = pdata->data_width[i];
+ dw->data_width = pdata->data_width;

/* Calculate all channel mask before DMA setup */
dw->all_chan_mask = (1 << pdata->nr_channels) - 1;
diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
index d3e1abcebd7f..89d0461f5dcc 100644
--- a/drivers/dma/dw/platform.c
+++ b/drivers/dma/dw/platform.c
@@ -102,8 +102,8 @@ dw_dma_parse_dt(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct dw_dma_platform_data *pdata;
- u32 tmp, arr[DW_DMA_MAX_NR_MASTERS];
u32 nr_channels;
+ u32 tmp;

if (!np) {
dev_err(&pdev->dev, "Missing DT data\n");
@@ -138,10 +138,8 @@ dw_dma_parse_dt(struct platform_device *pdev)
pdata->nr_masters = tmp;
}

- if (!of_property_read_u32_array(np, "data_width", arr,
- pdata->nr_masters))
- for (tmp = 0; tmp < pdata->nr_masters; tmp++)
- pdata->data_width[tmp] = arr[tmp];
+ if (!of_property_read_u32(np, "data-width", &tmp))
+ pdata->data_width = tmp;

return pdata;
}
diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h
index e4b277565165..87bc97fca084 100644
--- a/drivers/dma/dw/regs.h
+++ b/drivers/dma/dw/regs.h
@@ -285,7 +285,7 @@ struct dw_dma {

/* hardware configuration */
unsigned char nr_masters;
- unsigned char data_width[DW_DMA_MAX_NR_MASTERS];
+ unsigned char data_width;
};

static inline struct dw_dma_regs __iomem *__dw_regs(struct dw_dma *dw)
diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h
index b881b978e486..4120a3eb71ca 100644
--- a/include/linux/platform_data/dma-dw.h
+++ b/include/linux/platform_data/dma-dw.h
@@ -42,8 +42,7 @@ struct dw_dma_slave {
* @chan_priority: Set channel priority increasing from 0 to 7 or 7 to 0.
* @block_size: Maximum block size supported by the controller
* @nr_masters: Number of AHB masters supported by the controller
- * @data_width: Maximum data width supported by hardware per AHB master
- * (0 - 8bits, 1 - 16bits, ..., 5 - 256bits)
+ * @data_width: Maximum data width supported by hardware (in bytes)
*/
struct dw_dma_platform_data {
unsigned int nr_channels;
@@ -57,7 +56,7 @@ struct dw_dma_platform_data {
unsigned char chan_priority;
unsigned short block_size;
unsigned char nr_masters;
- unsigned char data_width[DW_DMA_MAX_NR_MASTERS];
+ unsigned char data_width;
};

#endif /* _PLATFORM_DATA_DMA_DW_H */
--
2.7.0

Next message: Mans Rullgard: "[PATCH 08/15] dmaengine: dw: define counter variables as unsigned int"
Previous message: Mans Rullgard: "[PATCH 06/15] dmaengine: dw: substitute dma_read_byaddr by dma_readl_native"
In reply to: Mans Rullgard: "[PATCH 06/15] dmaengine: dw: substitute dma_read_byaddr by dma_readl_native"
Next in thread: Vineet Gupta: "Re: [PATCH 07/15] dmaengine: dw: revisit data_width property"
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