dmaengine: mv_xor fixes and improvements

Hello,

Here is a v2 of the series making some fixes and improvements to the mv_xor driver.

Here are the changes compared to v1:

* Device Tree related changes omitted, since they have been applied by one of the ARM mach-mvebu maintainer.

* Addition of one commit, "dmaengine: mv_xor: fix big endian operation in register mode", fixing a regression introduced by one the patches currently in the 'next' branch of Vinod's repository. It should be merged as part of 4.2.

* Addition of two cleanup patches:

dmaengine: mv_xor: remove mv_xor_chan->current_type field
dmaengine: mv_xor: de-duplicate mv_chan_set_mode*()

These patches, like the two other non-fixes, can either go in 4.2 if it's not too late, or in 4.3.

Thanks,

Thomas

Thomas Petazzoni (5):
dmaengine: mv_xor: fix big endian operation in register mode
dmaengine: mv_xor: add suspend/resume support
dmaengine: mv_xor: remove support for dmacap,* DT properties
dmaengine: mv_xor: remove mv_xor_chan->current_type field
dmaengine: mv_xor: de-duplicate mv_chan_set_mode*()

 Documentation/devicetree/bindings/dma/mv-xor.txt | 10 +--
 drivers/dma/mv_xor.c                             | 97 +++++++++++++-----------
 drivers/dma/mv_xor.h                             |  2 +-
 3 files changed, 58 insertions(+), 51 deletions(-)

2.1.0

Commit 6f166312c6ea2 ("dmaengine: mv_xor: add support for a38x command in descriptor mode") introduced the support for a feature that appeared in Armada 38x: specifying the operation to be performed in a per-descriptor basis rather than globally per channel.

However, when doing so, it changed the function mv_chan_set_mode() to use:

if (IS_ENABLED(__BIG_ENDIAN))

instead of:

  #if defined(__BIG_ENDIAN)

While IS_ENABLED() is perfectly fine for CONFIG_* symbols, it is not for other symbols such as __BIG_ENDIAN that is provided directly by the compiler. Consequently, the commit broke support for big-endian, as the XOR_DESCRIPTOR_SWAP flag was not set in the XOR channel configuration register.

The primarily visible effect was some nasty warnings and failures appearing during the self-test of the XOR unit:

[    1.197368] mv_xor d0060900.xor: error on chan 0. intr cause 0x00000082
[    1.197393] mv_xor d0060900.xor: config       0x00008440
[    1.197410] mv_xor d0060900.xor: activation   0x00000000
[    1.197427] mv_xor d0060900.xor: intr cause   0x00000082
[    1.197443] mv_xor d0060900.xor: intr mask    0x000003f7
[    1.197460] mv_xor d0060900.xor: error cause  0x00000000
[    1.197477] mv_xor d0060900.xor: error addr   0x00000000
[    1.197491] ------------[ cut here ]------------
[    1.197513] WARNING: CPU: 0 PID: 1 at ../drivers/dma/mv_xor.c:664 mv_xor_interrupt_handler+0x14c/0x170()

See also:

http://storage.kernelci.org/next/next-20150617/arm-mvebu_v7_defconfig+CONFIG_CPU_BIG_ENDIAN=y/lab-khilman/boot-armada-xp-openblocks-ax3-4.txt

---
This fix should go in for 4.2.

---
 drivers/dma/mv_xor.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

index fbaf1ea..f1325f6 100644
@@ -162,10 +162,11 @@ static void mv_chan_set_mode(struct mv_xor_chan *chan,
 	config &= ~0x7;
 	config |= op_mode;
 
-	if (IS_ENABLED(__BIG_ENDIAN))
-		config |= XOR_DESCRIPTOR_SWAP;
-	else
-		config &= ~XOR_DESCRIPTOR_SWAP;
+#if defined(__BIG_ENDIAN)
+	config |= XOR_DESCRIPTOR_SWAP;
+#else
+	config &= ~XOR_DESCRIPTOR_SWAP;
+#endif
 
 	writel_relaxed(config, XOR_CONFIG(chan));
 	chan->current_type = type;

2.1.0

This commit adds suspend/resume support to the mv_xor driver. The config and interrupt mask registers must be saved and restored, and upon resume, the MBus windows configuration must also be done again.

Tested on Armada 388 GP, with a RAID 5 array, accessed before and after a suspend to RAM cycle.

Based on work from Ofer Heifetz and Lior Amsalem.

---
 drivers/dma/mv_xor.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 drivers/dma/mv_xor.h |  1 +
 2 files changed, 48 insertions(+)

index f1325f6..0a3ddc2 100644
@@ -1121,6 +1121,51 @@ mv_xor_conf_mbus_windows(struct mv_xor_device *xordev,
 	writel(0, base + WINDOW_OVERRIDE_CTRL(1));
 }
 
+static int mv_xor_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct mv_xor_device *xordev = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < MV_XOR_MAX_CHANNELS; i++) {
+		struct mv_xor_chan *mv_chan = xordev->channels[i];
+
+		if (!mv_chan)
+			continue;
+
+		mv_chan->saved_config_reg =
+			readl_relaxed(XOR_CONFIG(mv_chan));
+		mv_chan->saved_int_mask_reg =
+			readl_relaxed(XOR_INTR_MASK(mv_chan));
+	}
+
+	return 0;
+}
+
+static int mv_xor_resume(struct platform_device *dev)
+{
+	struct mv_xor_device *xordev = platform_get_drvdata(dev);
+	const struct mbus_dram_target_info *dram;
+	int i;
+
+	for (i = 0; i < MV_XOR_MAX_CHANNELS; i++) {
+		struct mv_xor_chan *mv_chan = xordev->channels[i];
+
+		if (!mv_chan)
+			continue;
+
+		writel_relaxed(mv_chan->saved_config_reg,
+			       XOR_CONFIG(mv_chan));
+		writel_relaxed(mv_chan->saved_int_mask_reg,
+			       XOR_INTR_MASK(mv_chan));
+	}
+
+	dram = mv_mbus_dram_info();
+	if (dram)
+		mv_xor_conf_mbus_windows(xordev, dram);
+
+	return 0;
+}
+
 static const struct of_device_id mv_xor_dt_ids[] = {
 	{ .compatible = "marvell,orion-xor", .data = (void *)XOR_MODE_IN_REG },
 	{ .compatible = "marvell,armada-380-xor", .data = (void *)XOR_MODE_IN_DESC },

@@ -1284,6 +1329,8 @@ static int mv_xor_remove(struct platform_device *pdev)
 static struct platform_driver mv_xor_driver = {
 	.probe		= mv_xor_probe,
 	.remove		= mv_xor_remove,
+	.suspend        = mv_xor_suspend,
+	.resume         = mv_xor_resume,
 	.driver		= {
 		.name	        = MV_XOR_NAME,
 		.of_match_table = of_match_ptr(mv_xor_dt_ids),

index b7455b4..41a2e8d 100644
@@ -126,6 +126,7 @@ struct mv_xor_chan {
 	char			dummy_src[MV_XOR_MIN_BYTE_COUNT];
 	char			dummy_dst[MV_XOR_MIN_BYTE_COUNT];
 	dma_addr_t		dummy_src_addr, dummy_dst_addr;
+	u32                     saved_config_reg, saved_int_mask_reg;
 };
 
 /**

2.1.0

The only reason why we had dmacap,* properties is because back when DMA_MEMSET was supported, only one out of the two channels per engine could do a memset operation. But this is something that the driver already knows anyway, and since then, the DMA_MEMSET support has been removed.

The driver is already well aware of what each channel supports and the one to one mapping between Linux specific implementation details (such as dmacap,interrupt enabling DMA_INTERRUPT) and DT properties is a good indication that these DT properties are wrong.

Therefore, this commit simply gets rid of these dmacap,* properties, they are now ignored, and the driver is responsible for knowing the capabilities of the hardware with regard to the dmaengine subsystem expectations.

---
 Documentation/devicetree/bindings/dma/mv-xor.txt | 10 ++++------
 drivers/dma/mv_xor.c                             |  9 +++------
 2 files changed, 7 insertions(+), 12 deletions(-)

index cc29c35..276ef81 100644
@@ -12,10 +12,13 @@ XOR engine has. Those sub-nodes have the following required
 properties:
 - interrupts: interrupt of the XOR channel
 
-And the following optional properties:
+The sub-nodes used to contain one or several of the following
+properties, but they are now deprecated:
 - dmacap,memcpy to indicate that the XOR channel is capable of memcpy operations
 - dmacap,memset to indicate that the XOR channel is capable of memset operations
 - dmacap,xor to indicate that the XOR channel is capable of xor operations
+- dmacap,interrupt to indicate that the XOR channel is capable of
+  generating interrupts
 
 Example:
 

@@ -28,13 +31,8 @@ xor at d0060900 {
 
 	xor00 {
 	      interrupts = <51>;
-	      dmacap,memcpy;
-	      dmacap,xor;
 	};
 	xor01 {
 	      interrupts = <52>;
-	      dmacap,memcpy;
-	      dmacap,xor;
-	      dmacap,memset;
 	};
 };

index 0a3ddc2..6aedc36 100644
@@ -1236,12 +1236,9 @@ static int mv_xor_probe(struct platform_device *pdev)
 			op_in_desc = (int)of_id->data;
 
 			dma_cap_zero(cap_mask);
-			if (of_property_read_bool(np, "dmacap,memcpy"))
-				dma_cap_set(DMA_MEMCPY, cap_mask);
-			if (of_property_read_bool(np, "dmacap,xor"))
-				dma_cap_set(DMA_XOR, cap_mask);
-			if (of_property_read_bool(np, "dmacap,interrupt"))
-				dma_cap_set(DMA_INTERRUPT, cap_mask);
+			dma_cap_set(DMA_MEMCPY, cap_mask);
+			dma_cap_set(DMA_XOR, cap_mask);
+			dma_cap_set(DMA_INTERRUPT, cap_mask);
 
 			irq = irq_of_parse_and_map(np, 0);
 			if (!irq) {

2.1.0

Maxime

Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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Since commit 3e4f52e2da9f6 ("dma: mv_xor: Simplify the DMA_MEMCPY operation"), this field is no longer used, so get rid of it.

---
 drivers/dma/mv_xor.c | 1 -
 drivers/dma/mv_xor.h | 1 -
 2 files changed, 2 deletions(-)

index 6aedc36..1fe3e33 100644
@@ -169,7 +169,6 @@ static void mv_chan_set_mode(struct mv_xor_chan *chan,
 #endif
 
 	writel_relaxed(config, XOR_CONFIG(chan));
-	chan->current_type = type;
 }
 
 static void mv_chan_set_mode_to_desc(struct mv_xor_chan *chan)

index 41a2e8d..c19fe30 100644
@@ -110,7 +110,6 @@ struct mv_xor_chan {
 	void __iomem		*mmr_high_base;
 	unsigned int		idx;
 	int                     irq;
-	enum dma_transaction_type	current_type;
 	struct list_head	chain;
 	struct list_head	free_slots;
 	struct list_head	allocated_slots;

2.1.0

When commit 6f166312c6ea2 ("dmaengine: mv_xor: add support for a38x command in descriptor mode") added support for the descriptor mode available in Marvell Armada 38x and later SoCs, it added a new function mv_chan_set_mode_to_desc() which allows to configure a XOR channel to get the specific operation to be done from each individual DMA descriptor.

However, this function was mainly a duplicate of the existing mv_chan_set_mode(), with just the operation being different.

This commit re-organizes the code into a single mv_chan_set_mode() function, which takes the operation mode as argument, and the mv_xor_channel_add() function decides whether to use XOR_OPERATION_MODE_IN_DESC or XOR_OPERATION_MODE_XOR.

---
 drivers/dma/mv_xor.c | 41 +++--------------------------------------
 1 file changed, 3 insertions(+), 38 deletions(-)

index 1fe3e33..6e09d59 100644
@@ -139,45 +139,10 @@ static void mv_chan_clear_err_status(struct mv_xor_chan *chan)
 }
 
 static void mv_chan_set_mode(struct mv_xor_chan *chan,
-			     enum dma_transaction_type type)
+			     u32 op_mode)
 {
-	u32 op_mode;
 	u32 config = readl_relaxed(XOR_CONFIG(chan));
 
-	switch (type) {
-	case DMA_XOR:
-		op_mode = XOR_OPERATION_MODE_XOR;
-		break;
-	case DMA_MEMCPY:
-		op_mode = XOR_OPERATION_MODE_MEMCPY;
-		break;
-	default:
-		dev_err(mv_chan_to_devp(chan),
-			"error: unsupported operation %d\n",
-			type);
-		BUG();
-		return;
-	}
-
-	config &= ~0x7;
-	config |= op_mode;
-
-#if defined(__BIG_ENDIAN)
-	config |= XOR_DESCRIPTOR_SWAP;
-#else
-	config &= ~XOR_DESCRIPTOR_SWAP;
-#endif
-
-	writel_relaxed(config, XOR_CONFIG(chan));
-}
-
-static void mv_chan_set_mode_to_desc(struct mv_xor_chan *chan)
-{
-	u32 op_mode;
-	u32 config = readl_relaxed(XOR_CONFIG(chan));
-
-	op_mode = XOR_OPERATION_MODE_IN_DESC;
-
 	config &= ~0x7;
 	config |= op_mode;
 

@@ -1042,9 +1007,9 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
 	mv_chan_unmask_interrupts(mv_chan);
 
 	if (mv_chan->op_in_desc == XOR_MODE_IN_DESC)
-		mv_chan_set_mode_to_desc(mv_chan);
+		mv_chan_set_mode(mv_chan, XOR_OPERATION_MODE_IN_DESC);
 	else
-		mv_chan_set_mode(mv_chan, DMA_XOR);
+		mv_chan_set_mode(mv_chan, XOR_OPERATION_MODE_XOR);
 
 	spin_lock_init(&mv_chan->lock);
 	INIT_LIST_HEAD(&mv_chan->chain);

2.1.0

Maxime

Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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