dmaengine: dw-axi-dmac: support parallel memory <--> peripheral transfers

PATCH Superseded [email protected] 2 participants 6 messages Jul 20, 2021 – Jul 29, 2021

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dmaengine Synopsys DesignWare AXI DMAC driver

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[email protected]

author

2021-07-20 17:47 UTC #0 lore raw

v4 cover dmaengine: dw-axi-dmac: support parallel memory <--> peripheral transfers

From: Pandith N <[email protected]>

Added support for multiple DMA_MEM_TO_DEV, DMA_DEV_TO_MEM transfers in parallel. Peripherals can use DMA for both transmit and receive operations in parallel.

To setup DMA handshaking, the peripheral source number to be programmed in respective channel select slot of AXIDMA_CTRL_DMA_HS_SEL. No need to check for free slot in dw_axi_dma_set_hw_channel().

The channel slot used in AXIDMA_CTRL_DMA_HS_SEL needs to be set in src_per/dst_per of CHx_CFG register

Burst length, DMA HW capability set in dt-binding is now used in driver.

Changes since v1:
Added new macro, magic mask for HW handshake select. Typos in commit message are corrected

Changes since v2:
Split the patch as follows
Patch 1: Remove free slot check algorithm in dw_axi_dma_set_hw_channel() Patch 2: The channel slot used needs to be set in CHx_CFG src/dst_per Patch 3: Usage of burst length HW capability

Changes in v3:
Patch 1: Added description for hardware handshake settings

Pandith N (3):
dmaengine: dw-axi-dmac: Remove free slot check algorithm in
dw_axi_dma_set_hw_channel
dmaengine: dw-axi-dmac: support parallel memory <--> peripheral
transfers
dmaengine: dw-axi-dmac: Burst length settings

 .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 56 +++++++++----------
 drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |  4 ++
 2 files changed, 29 insertions(+), 31 deletions(-)

Signature · 1 line

2.17.1

[email protected]

author

2021-07-20 17:47 UTC #1 lore raw

PATCH v4 1/3 dmaengine: dw-axi-dmac: Remove free slot check algorithm in dw_axi_dma_set_hw_channel

From: Pandith N <[email protected]>

Removed free slot check algorithm in dw_axi_dma_set_hw_channel. For 8 DMA channels, use respective handshake slot in DMA_HS_SEL APB register.

For every channel, an dedicated slot is provided in hardware handshake register AXIDMA_CTRL_DMA_HS_SEL_n. Peripheral source number is programmed in respective channel slots.

Signed-off-by Pandith N <[email protected]>

Tested-by Pan Kris <[email protected]>

---
 .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 49 +++++++------------
 drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |  2 +
 2 files changed, 21 insertions(+), 30 deletions(-)

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +19 ~~-30~~

index d9e4ac3edb4e..6b871e20ae27 100644
@@ -470,19 +470,14 @@ static void dma_chan_free_chan_resources(struct dma_chan *dchan)
 	pm_runtime_put(chan->chip->dev);
 }
 
-static void dw_axi_dma_set_hw_channel(struct axi_dma_chip *chip,
-				      u32 handshake_num, bool set)
+static int dw_axi_dma_set_hw_channel(struct axi_dma_chan *chan, bool set)
 {
-	unsigned long start = 0;
-	unsigned long reg_value;
-	unsigned long reg_mask;
-	unsigned long reg_set;
-	unsigned long mask;
-	unsigned long val;
+	struct axi_dma_chip *chip = chan->chip;
+	unsigned long reg_value, val;
 
 	if (!chip->apb_regs) {
 		dev_dbg(chip->dev, "apb_regs not initialized\n");
-		return;
+		return -EINVAL;
 	}
 
 	/*

@@ -490,26 +485,22 @@ static void dw_axi_dma_set_hw_channel(struct axi_dma_chip *chip,
 	 * Lock the DMA channel by assign a handshake number to the channel.
 	 * Unlock the DMA channel by assign 0x3F to the channel.
 	 */
-	if (set) {
-		reg_set = UNUSED_CHANNEL;
-		val = handshake_num;
-	} else {
-		reg_set = handshake_num;
+	if (set)
+		val = chan->hw_handshake_num;
+	else
 		val = UNUSED_CHANNEL;
-	}
 
 	reg_value = lo_hi_readq(chip->apb_regs + DMAC_APB_HW_HS_SEL_0);
 
-	for_each_set_clump8(start, reg_mask, &reg_value, 64) {
-		if (reg_mask == reg_set) {
-			mask = GENMASK_ULL(start + 7, start);
-			reg_value &= ~mask;
-			reg_value |= rol64(val, start);
-			lo_hi_writeq(reg_value,
-				     chip->apb_regs + DMAC_APB_HW_HS_SEL_0);
-			break;
-		}
-	}
+	/* Channel is already allocated, set handshake as per channel ID */
+	/* 64 bit write should handle for 8 channels */
+
+	reg_value &= ~(DMA_APB_HS_SEL_MASK <<
+			(chan->id * DMA_APB_HS_SEL_BIT_SIZE));
+	reg_value |= (val << (chan->id * DMA_APB_HS_SEL_BIT_SIZE));
+	lo_hi_writeq(reg_value, chip->apb_regs + DMAC_APB_HW_HS_SEL_0);
+
+	return 0;
 }
 
 /*

@@ -742,7 +733,7 @@ dw_axi_dma_chan_prep_cyclic(struct dma_chan *dchan, dma_addr_t dma_addr,
 		llp = hw_desc->llp;
 	} while (total_segments);
 
-	dw_axi_dma_set_hw_channel(chan->chip, chan->hw_handshake_num, true);
+	dw_axi_dma_set_hw_channel(chan, true);
 
 	return vchan_tx_prep(&chan->vc, &desc->vd, flags);

@@ -822,7 +813,7 @@ dw_axi_dma_chan_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl,
 		llp = hw_desc->llp;
 	} while (num_sgs);
 
-	dw_axi_dma_set_hw_channel(chan->chip, chan->hw_handshake_num, true);
+	dw_axi_dma_set_hw_channel(chan, true);
 
 	return vchan_tx_prep(&chan->vc, &desc->vd, flags);

@@ -1098,8 +1089,7 @@ static int dma_chan_terminate_all(struct dma_chan *dchan)
 			 "%s failed to stop\n", axi_chan_name(chan));
 
 	if (chan->direction != DMA_MEM_TO_MEM)
-		dw_axi_dma_set_hw_channel(chan->chip,
-					  chan->hw_handshake_num, false);
+		dw_axi_dma_set_hw_channel(chan, false);
 	if (chan->direction == DMA_MEM_TO_DEV)
 		dw_axi_dma_set_byte_halfword(chan, false);

@@ -1365,7 +1355,6 @@ static int dw_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-
 	INIT_LIST_HEAD(&dw->dma.channels);
 	for (i = 0; i < hdata->nr_channels; i++) {
 		struct axi_dma_chan *chan = &dw->chan[i];

drivers/dma/dw-axi-dmac/dw-axi-dmac.h +2 -0

index b69897887c76..358f553cafe9 100644
@@ -184,6 +184,8 @@ static inline struct axi_dma_chan *dchan_to_axi_dma_chan(struct dma_chan *dchan)
 #define DMAC_APB_HALFWORD_WR_CH_EN	0x020 /* DMAC Halfword write enables */
 
 #define UNUSED_CHANNEL		0x3F /* Set unused DMA channel to 0x3F */
+#define DMA_APB_HS_SEL_BIT_SIZE	0x08 /* HW handshake bits per channel */
+#define DMA_APB_HS_SEL_MASK	0xFF /* HW handshake select masks */
 #define MAX_BLOCK_SIZE		0x1000 /* 1024 blocks * 4 bytes data width */
 
 /* DMAC_CFG */

Signature · 1 line

2.17.1

Vinod Koul

maintainer

2021-07-28 07:23 UTC #2 lore raw

Re: [PATCH V4 1/3] dmaengine: dw-axi-dmac: Remove free slot check algorithm in dw_axi_dma_set_hw_channel

Quoted 21 lines · On 20-07-21, 23:17, [email protected] wrote:

From: Pandith N <[email protected]>
Removed free slot check algorithm in dw_axi_dma_set_hw_channel. For 8 DMA channels, use respective handshake slot in DMA_HS_SEL APB register.
For every channel, an dedicated slot is provided in hardware handshake register AXIDMA_CTRL_DMA_HS_SEL_n. Peripheral source number is programmed in respective channel slots.
Signed-off-by Pandith N <[email protected]>
Tested-by Pan Kris <[email protected]>
---
 .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 49 +++++++------------
 drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |  2 +
 2 files changed, 21 insertions(+), 30 deletions(-)
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +0 -0
index d9e4ac3edb4e..6b871e20ae27 100644

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c static void dma_chan_free_chan_resources(struct dma_chan *dchan) · line 473

Quoted 6 lines

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +1 -2

@@ -470,19 +470,14 @@ static void dma_chan_free_chan_resources(struct dma_chan *dchan)
 	pm_runtime_put(chan->chip->dev);
 }
 
-static void dw_axi_dma_set_hw_channel(struct axi_dma_chip *chip,
-				      u32 handshake_num, bool set)
+static int dw_axi_dma_set_hw_channel(struct axi_dma_chan *chan, bool set)

what is point of returning error if that is not checked and action taken in caller?

Quoted 4 lines

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +0 -3
 {
-	unsigned long start = 0;
-	unsigned long reg_value;
-	unsigned long reg_mask;

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c static void dma_chan_free_chan_resources(struct dma_chan *dchan) · line 480

Quoted 10 lines

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +3 -4

-	unsigned long reg_set;
-	unsigned long mask;
-	unsigned long val;
+	struct axi_dma_chip *chip = chan->chip;
+	unsigned long reg_value, val;
 
 	if (!chip->apb_regs) {
 		dev_dbg(chip->dev, "apb_regs not initialized\n");
-		return;
+		return -EINVAL;

should the above log not be error now?

Signature · 1 line

~Vinod

N, Pandith

author

2021-07-29 10:36 UTC #3 lore raw

RE: [PATCH V4 1/3] dmaengine: dw-axi-dmac: Remove free slot check algorithm in dw_axi_dma_set_hw_channel

Quoted 41 lines

-----Original Message-----
From: Vinod Koul <[email protected]>
Sent: Wednesday, July 28, 2021 12:53 PM
To: N, Pandith <[email protected]>
Cc: [email protected]; [email protected]; Raja Subramanian, Lakshmi Bai <[email protected]>; Pan, Kris <[email protected]>; Sangannavar, Mallikarjunappa <[email protected]>; Thokala, Srikanth <[email protected]>
Subject: Re: [PATCH V4 1/3] dmaengine: dw-axi-dmac: Remove free slot check algorithm in dw_axi_dma_set_hw_channel
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c static void dma_chan_free_chan_resources(struct
Quoted 22 lines · On 20-07-21, 23:17, [email protected] wrote:
From: Pandith N <[email protected]>
Removed free slot check algorithm in dw_axi_dma_set_hw_channel. For 8 DMA channels, use respective handshake slot in DMA_HS_SEL APB register.
For every channel, an dedicated slot is provided in hardware handshake register AXIDMA_CTRL_DMA_HS_SEL_n. Peripheral source number is programmed in respective channel slots.
Signed-off-by Pandith N <[email protected]>
Tested-by Pan Kris <[email protected]>
---
 .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 49 +++++++------------
 drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |  2 +
 2 files changed, 21 insertions(+), 30 deletions(-)
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +0 -0
index d9e4ac3edb4e..6b871e20ae27 100644
@@ -470,19 +470,14 @@ static void dma_chan_free_chan_resources(struct
dma_chan *dchan)
Quoted 3 lines
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +0 -0
 	pm_runtime_put(chan->chip->dev);
 }
 

Quoted 7 lines

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c static void dma_chan_free_chan_resources(struct dma_chan *dchan)
Quoted 4 lines
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +2 -2
-static void dw_axi_dma_set_hw_channel(struct axi_dma_chip *chip,
-				      u32 handshake_num, bool set)
+static int dw_axi_dma_set_hw_channel(struct axi_dma_chan *chan, bool
+set)
what is point of returning error if that is not checked and action taken in caller?

Yes, change of function return type is not required here. API signature will be:
static void dw_axi_dma_set_hw_channel(struct axi_dma_chan *chan, bool set)

Quoted 10 lines

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +2 -6

 {
-	unsigned long start = 0;
-	unsigned long reg_value;
-	unsigned long reg_mask;
-	unsigned long reg_set;
-	unsigned long mask;
-	unsigned long val;
+	struct axi_dma_chip *chip = chan->chip;
+	unsigned long reg_value, val;

Quoted 6 lines

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c static void dma_chan_free_chan_resources(struct dma_chan *dchan) · line 480
Quoted 4 lines
drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +1 -1
 	if (!chip->apb_regs) {
 		dev_dbg(chip->dev, "apb_regs not initialized\n");
-		return;
+		return -EINVAL;
should the above log not be error now?

Will change this to dev_err

Quoted 2 lines

--
~Vinod

[email protected]

author

2021-07-20 17:47 UTC #4 lore raw

PATCH v4 2/3 dmaengine: dw-axi-dmac: support parallel memory <--> peripheral transfers

In reply to [email protected]

From: Pandith N <[email protected]>

Added support for multiple DMA_MEM_TO_DEV, DMA_DEV_TO_MEM transfers in parallel. This is required for peripherals using DMA for transmit and receive operations at the same time. APB slot number needs to be programmed in channel hardware handshaking interface

Signed-off-by Pandith N <[email protected]>

Tested-by Pan Kris <[email protected]>

---
 drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 4 ++++
 drivers/dma/dw-axi-dmac/dw-axi-dmac.h          | 2 ++
 2 files changed, 6 insertions(+)

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +4 -0

index 6b871e20ae27..2c9a3cc204e2 100644
@@ -363,12 +363,16 @@ static void axi_chan_block_xfer_start(struct axi_dma_chan *chan,
 			DWAXIDMAC_TT_FC_MEM_TO_PER_DST :
 			DWAXIDMAC_TT_FC_MEM_TO_PER_DMAC)
 			<< CH_CFG_H_TT_FC_POS;
+		if (chan->chip->apb_regs)
+			reg |= (chan->id << CH_CFG_H_DST_PER_POS);
 		break;
 	case DMA_DEV_TO_MEM:
 		reg |= (chan->config.device_fc ?
 			DWAXIDMAC_TT_FC_PER_TO_MEM_SRC :
 			DWAXIDMAC_TT_FC_PER_TO_MEM_DMAC)
 			<< CH_CFG_H_TT_FC_POS;
+		if (chan->chip->apb_regs)
+			reg |= (chan->id << CH_CFG_H_SRC_PER_POS);
 		break;
 	default:
 		break;

drivers/dma/dw-axi-dmac/dw-axi-dmac.h +2 -0

index 358f553cafe9..380005afde16 100644
@@ -258,6 +258,8 @@ enum {
 
 /* CH_CFG_H */
 #define CH_CFG_H_PRIORITY_POS		17
+#define CH_CFG_H_DST_PER_POS		12
+#define CH_CFG_H_SRC_PER_POS		7
 #define CH_CFG_H_HS_SEL_DST_POS		4
 #define CH_CFG_H_HS_SEL_SRC_POS		3
 enum {

Signature · 1 line

2.17.1

[email protected]

author

2021-07-20 17:47 UTC #5 lore raw

PATCH v4 3/3 dmaengine: dw-axi-dmac: Burst length settings

In reply to [email protected]

From: Pandith N <[email protected]>

Burst length, DMA HW capability set in dt-binding is now used in driver.

Signed-off-by Pandith N <[email protected]>

Tested-by Pan Kris <[email protected]>

---
 drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c +2 -1

index 2c9a3cc204e2..aace3751c56e 100644
@@ -1290,7 +1290,7 @@ static int parse_device_properties(struct axi_dma_chip *chip)
 			return -EINVAL;
 
 		chip->dw->hdata->restrict_axi_burst_len = true;
-		chip->dw->hdata->axi_rw_burst_len = tmp - 1;
+		chip->dw->hdata->axi_rw_burst_len = tmp;
 	}
 
 	return 0;

@@ -1379,6 +1379,7 @@ static int dw_probe(struct platform_device *pdev)
 
 	/* DMA capabilities */
 	dw->dma.chancnt = hdata->nr_channels;
+	dw->dma.max_burst = hdata->axi_rw_burst_len;
 	dw->dma.src_addr_widths = AXI_DMA_BUSWIDTHS;
 	dw->dma.dst_addr_widths = AXI_DMA_BUSWIDTHS;
 	dw->dma.directions = BIT(DMA_MEM_TO_MEM);

Signature · 1 line

2.17.1