[PATCH v7 2/4] dmaengine: dw: revisit data_width property
From: Andy Shevchenko
Date: Wed Apr 27 2016 - 07:16:52 EST
There several changes are done here:
- Convert the property to be in bytes
Besides that this is a common practice for such property, the use of a value
in bytes much more convenient than handling the encoded one.
- Rename data_width to data-width in the device tree bindings
The change leaves the support for the old format as well just in case someone
will use a newer kernel with an old device tree blob.
- While here, replace dwc_fast_ffs() by __ffs()
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
Documentation/devicetree/bindings/dma/snps-dma.txt | 7 +++-
arch/arc/boot/dts/abilis_tb10x.dtsi | 2 +-
arch/arm/boot/dts/spear13xx.dtsi | 4 +--
drivers/dma/dw/core.c | 42 ++++++----------------
drivers/dma/dw/platform.c | 5 ++-
include/linux/platform_data/dma-dw.h | 2 +-
6 files changed, 24 insertions(+), 38 deletions(-)
diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt b/Documentation/devicetree/bindings/dma/snps-dma.txt
index c99c1ff..0f55832 100644
--- a/Documentation/devicetree/bindings/dma/snps-dma.txt
+++ b/Documentation/devicetree/bindings/dma/snps-dma.txt
@@ -13,6 +13,11 @@ 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
+ (in bytes, power of 2)
+
+
+Deprecated properties:
- data_width: Maximum data width supported by hardware per AHB master
(0 - 8bits, 1 - 16bits, ..., 5 - 256bits)
@@ -38,7 +43,7 @@ Example:
chan_allocation_order = <1>;
chan_priority = <1>;
block_size = <0xfff>;
- data_width = <3 3>;
+ data-width = <8 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 663671f2..de53f5c 100644
--- a/arch/arc/boot/dts/abilis_tb10x.dtsi
+++ b/arch/arc/boot/dts/abilis_tb10x.dtsi
@@ -126,7 +126,7 @@
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 14594ce..449acf0 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 8>;
};
dma@eb000000 {
@@ -133,7 +133,7 @@
chan_allocation_order = <1>;
chan_priority = <1>;
block_size = <0xfff>;
- data_width = <3 3>;
+ data-width = <8 8>;
};
fsmc: flash@b0000000 {
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 78522dc..992da25 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -162,21 +162,6 @@ 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),
@@ -677,11 +662,12 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
struct dw_desc *prev;
size_t xfer_count;
size_t offset;
+ u8 m_master = dwc->m_master;
unsigned int src_width;
unsigned int dst_width;
- unsigned int data_width;
+ unsigned int data_width = dw->data_width[m_master];
u32 ctllo;
- u8 lms = DWC_LLP_LMS(dwc->m_master);
+ u8 lms = DWC_LLP_LMS(m_master);
dev_vdbg(chan2dev(chan),
"%s: d%pad s%pad l0x%zx f0x%lx\n", __func__,
@@ -694,10 +680,7 @@ 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(data_width | src | dest | len);
ctllo = DWC_DEFAULT_CTLLO(chan)
| DWC_CTLL_DST_WIDTH(dst_width)
@@ -757,11 +740,12 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
struct dw_desc *prev;
struct dw_desc *first;
u32 ctllo;
- u8 lms = DWC_LLP_LMS(dwc->m_master);
+ u8 m_master = dwc->m_master;
+ u8 lms = DWC_LLP_LMS(m_master);
dma_addr_t reg;
unsigned int reg_width;
unsigned int mem_width;
- unsigned int data_width;
+ unsigned int data_width = dw->data_width[m_master];
unsigned int i;
struct scatterlist *sg;
size_t total_len = 0;
@@ -787,8 +771,6 @@ 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;
@@ -796,8 +778,7 @@ 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(data_width | mem | len);
slave_sg_todev_fill_desc:
desc = dwc_desc_get(dwc);
@@ -843,8 +824,6 @@ 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;
@@ -852,8 +831,7 @@ 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(data_width | mem | len);
slave_sg_fromdev_fill_desc:
desc = dwc_desc_get(dwc);
@@ -1500,7 +1478,7 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
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;
+ 4 << (dw_params >> DW_PARAMS_DATA_WIDTH(i) & 3);
}
max_blk_size = dma_readl(dw, MAX_BLK_SIZE);
diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
index e65ebe5..2420fb7 100644
--- a/drivers/dma/dw/platform.c
+++ b/drivers/dma/dw/platform.c
@@ -138,9 +138,12 @@ dw_dma_parse_dt(struct platform_device *pdev)
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)) {
+ 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);
}
return pdata;
diff --git a/include/linux/platform_data/dma-dw.h b/include/linux/platform_data/dma-dw.h
index b881b97..ad76811 100644
--- a/include/linux/platform_data/dma-dw.h
+++ b/include/linux/platform_data/dma-dw.h
@@ -43,7 +43,7 @@ struct dw_dma_slave {
* @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)
+ * (in bytes, power of 2)
*/
struct dw_dma_platform_data {
unsigned int nr_channels;
--
2.8.0.rc3