DMAEngine support for sun4i, sun5i & sun7i

This patch adds support for the DMA engine present on Allwinner A10, A13, A10S and A20 SoCs. This engine has two kinds of channels: normal and dedicated. The main difference is in the mode of operation; while a single normal channel may be operating at any given time, dedicated channels may operate simultaneously provided there is no overlap of source or destination.

Hardware documentation can be found on A10 User Manual (section 12), A13 User Manual (section 14) and A20 User Manual (section 1.12)

Signed-off-by Emilio L?pez <[email protected]>

---

Changes from v1:
* address comments from Chen-Yu and Maxime
* fix issue converting bus width
* switch to using a threaded IRQ instead of a tasklet on recommendation from Maxime
* fix issue setting magic timing parameter for SPI transfers
* fix an issue with list handling reported by the kbuild 0-DAY robot (thanks!)
* drop a lot of unused #define
* probably some more stuff I'm forgetting

 .../devicetree/bindings/dma/sun4i-dma.txt          |   45 +
 drivers/dma/Kconfig                                |   10 +
 drivers/dma/Makefile                               |    1 +
 drivers/dma/sun4i-dma.c                            | 1025 ++++++++++++++++++++
 4 files changed, 1081 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/sun4i-dma.txt
 create mode 100644 drivers/dma/sun4i-dma.c

Documentation/devicetree/bindings/dma/sun4i-dma.txt new file +1 -0

new file mode 100644
index 0000000..f5661a5
@@ -0,0 +1,45 @@
+Allwinner A10 DMA Controller

Documentation/devicetree/bindings/dma/sun4i-dma.txt new file +4 -0

+
+Example:
+       spi2: spi at 01c17000 {
+               compatible = "allwinner,sun4i-a10-spi";

This patch adds support for the DMA engine present on Allwinner A10,

This patch adds support for the DMA engine present on Allwinner A10, A13, A10S and A20 SoCs. This engine has two kinds of channels: normal and dedicated. The main difference is in the mode of operation; while a single normal channel may be operating at any given time, dedicated channels may operate simultaneously provided there is no overlap of source or destination.

Hardware documentation can be found on A10 User Manual (section 12), A13 User Manual (section 14) and A20 User Manual (section 1.12)

Signed-off-by Emilio L?pez <[email protected]>

---

Changes from v1:
* address comments from Chen-Yu and Maxime
* fix issue converting bus width
* switch to using a threaded IRQ instead of a tasklet on recommendation from Maxime
* fix issue setting magic timing parameter for SPI transfers
* fix an issue with list handling reported by the kbuild 0-DAY robot (thanks!)
* drop a lot of unused #define
* probably some more stuff I'm forgetting

 .../devicetree/bindings/dma/sun4i-dma.txt          |   45 +
 drivers/dma/Kconfig                                |   10 +
 drivers/dma/Makefile                               |    1 +
 drivers/dma/sun4i-dma.c                            | 1025 ++++++++++++++++++++
 4 files changed, 1081 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/sun4i-dma.txt
 create mode 100644 drivers/dma/sun4i-dma.c

Documentation/devicetree/bindings/dma/sun4i-dma.txt new file +45 -0

new file mode 100644
index 0000000..f5661a5
@@ -0,0 +1,45 @@
+Allwinner A10 DMA Controller
+
+This driver follows the generic DMA bindings defined in dma.txt.
+
+Required properties:
+
+- compatible:	Must be "allwinner,sun4i-a10-dma"
+- reg:		Should contain the registers base address and length
+- interrupts:	Should contain a reference to the interrupt used by this device
+- clocks:	Should contain a reference to the parent AHB clock
+- #dma-cells :	Should be 1, a single cell holding a line request number
+
+Example:
+	dma: dma-controller at 01c02000 {
+		compatible = "allwinner,sun4i-a10-dma";
+		reg = <0x01c02000 0x1000>;
+		interrupts = <27>;
+		clocks = <&ahb_gates 6>;
+		#dma-cells = <1>;
+	};
+
+Clients:
+
+DMA clients connected to the Allwinner A10 DMA controller must use the
+format described in the dma.txt file, using a three-cell specifier for
+each channel: a phandle plus two integer cells.
+The three cells in order are:
+
+1. A phandle pointing to the DMA controller.
+2. Whether it is using normal (0) or dedicated (1) channels
+2. The port ID as specified in the datasheet
+
+Example:
+	spi2: spi at 01c17000 {
+		compatible = "allwinner,sun4i-a10-spi";
+		reg = <0x01c17000 0x1000>;
+		interrupts = <0 12 4>;
+		clocks = <&ahb_gates 22>, <&spi2_clk>;
+		clock-names = "ahb", "mod";
+		dmas = <&dma 1 29>, <&dma 1 28>;
+		dma-names = "rx", "tx";
+		status = "disabled";
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};

drivers/dma/Kconfig +0 -0

index 1eca7b9..cfa6e0a 100644

drivers/dma/Kconfig +4 -0

+	help
+	  Enable support for the DMA controller present in the sun4i,
+	  sun5i and sun7i Allwinner ARM SoCs.
+
 config DMA_ENGINE
 	bool
 

drivers/dma/Makefile +1 -0

index c779e1e..430de61 100644
@@ -47,3 +47,4 @@ obj-$(CONFIG_MOXART_DMA) += moxart-dma.o
 obj-$(CONFIG_FSL_EDMA) += fsl-edma.o
 obj-$(CONFIG_QCOM_BAM_DMA) += qcom_bam_dma.o
 obj-y += xilinx/
+obj-$(CONFIG_SUN4I_DMA) += sun4i-dma.o

drivers/dma/sun4i-dma.c new file +19 -0

new file mode 100644
index 0000000..24fa391
@@ -0,0 +1,1025 @@
+/*
+ * Copyright (C) 2014 Emilio L?pez
+ * Emilio L?pez <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/dmaengine.h>
+#include <linux/dmapool.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>

drivers/dma/sun4i-dma.c new file +270 -0

+
+/** Normal DMA register layout **/
+
+/* Normal DMA configuration register layout */
+#define NDMA_CFG_LOADING			BIT(31)
+#define NDMA_CFG_CONT_MODE			BIT(30)
+#define NDMA_CFG_WAIT_STATE(n)			((n) << 27)
+#define NDMA_CFG_DEST_DATA_WIDTH(width)		((width) << 25)
+#define NDMA_CFG_DEST_BURST_LENGTH(len)		((len) << 23)
+#define NDMA_CFG_DEST_NON_SECURE		BIT(22)
+#define NDMA_CFG_DEST_FIXED_ADDR		BIT(21)
+#define NDMA_CFG_DEST_DRQ_TYPE(type)		((type) << 16)
+#define NDMA_CFG_BYTE_COUNT_MODE_REMAIN		BIT(15)
+#define NDMA_CFG_SRC_DATA_WIDTH(width)		((width) << 9)
+#define NDMA_CFG_SRC_BURST_LENGTH(len)		((len) << 7)
+#define NDMA_CFG_SRC_NON_SECURE			BIT(6)
+#define NDMA_CFG_SRC_FIXED_ADDR			BIT(5)
+#define NDMA_CFG_SRC_DRQ_TYPE(type)		((type) << 0)
+
+/** Dedicated DMA register values **/
+
+/* Dedicated DMA source/destination address mode values */
+#define DDMA_ADDR_MODE_LINEAR			0
+#define DDMA_ADDR_MODE_IO			1
+#define DDMA_ADDR_MODE_HORIZONTAL_PAGE		2
+#define DDMA_ADDR_MODE_VERTICAL_PAGE		3
+
+/* Dedicated DMA source/destination data request type values */
+#define DDMA_DRQ_TYPE_SDRAM			0x1
+#define DDMA_DRQ_TYPE_LIMIT			(0x1F + 1)
+
+/** Dedicated DMA register layout **/
+
+/* Dedicated DMA configuration register layout */
+#define DDMA_CFG_LOADING			BIT(31)
+#define DDMA_CFG_BUSY				BIT(30)
+#define DDMA_CFG_CONT_MODE			BIT(29)
+#define DDMA_CFG_DEST_NON_SECURE		BIT(28)
+#define DDMA_CFG_DEST_DATA_WIDTH(width)		((width) << 25)
+#define DDMA_CFG_DEST_BURST_LENGTH(len)		((len) << 23)
+#define DDMA_CFG_DEST_ADDR_MODE(mode)		((mode) << 21)
+#define DDMA_CFG_DEST_DRQ_TYPE(type)		((type) << 16)
+#define DDMA_CFG_BYTE_COUNT_MODE_REMAIN		BIT(15)
+#define DDMA_CFG_SRC_NON_SECURE			BIT(12)
+#define DDMA_CFG_SRC_DATA_WIDTH(width)		((width) << 9)
+#define DDMA_CFG_SRC_BURST_LENGTH(len)		((len) << 7)
+#define DDMA_CFG_SRC_ADDR_MODE(mode)		((mode) << 5)
+#define DDMA_CFG_SRC_DRQ_TYPE(type)		((type) << 0)
+
+/* Dedicated DMA parameter register layout */
+#define DDMA_PARA_DEST_DATA_BLK_SIZE(n)		(((n) - 1) << 24)
+#define DDMA_PARA_DEST_WAIT_CYCLES(n)		(((n) - 1) << 16)
+#define DDMA_PARA_SRC_DATA_BLK_SIZE(n)		(((n) - 1) << 8)
+#define DDMA_PARA_SRC_WAIT_CYCLES(n)		(((n) - 1) << 0)
+
+/** DMA register offsets **/
+
+/* General register offsets */
+#define DMA_IRQ_ENABLE_REG			0x0
+#define DMA_IRQ_PENDING_STATUS_REG		0x4
+
+/* Normal DMA register offsets */
+#define NDMA_CHANNEL_REG_BASE(n)		(0x100 + (n) * 0x20)
+#define NDMA_CFG_REG				0x0
+#define NDMA_SRC_ADDR_REG			0x4
+#define NDMA_DEST_ADDR_REG			0x8
+#define NDMA_BYTE_COUNT_REG			0xC
+
+/* Dedicated DMA register offsets */
+#define DDMA_CHANNEL_REG_BASE(n)		(0x300 + (n) * 0x20)
+#define DDMA_CFG_REG				0x0
+#define DDMA_SRC_ADDR_REG			0x4
+#define DDMA_DEST_ADDR_REG			0x8
+#define DDMA_BYTE_COUNT_REG			0xC
+#define DDMA_PARA_REG				0x18
+
+/** DMA Driver **/
+
+/*
+ * Normal DMA has 8 channels, and Dedicated DMA has another 8, so that's
+ * 16 channels. As for endpoints, there's 29 and 21 respectively. Given
+ * that the Normal DMA endpoints (other than SDRAM) can be used as tx/rx,
+ * we need 78 vchans in total
+ */
+#define NDMA_NR_MAX_CHANNELS	8
+#define DDMA_NR_MAX_CHANNELS	8
+#define DMA_NR_MAX_CHANNELS	(NDMA_NR_MAX_CHANNELS + DDMA_NR_MAX_CHANNELS)
+#define NDMA_NR_MAX_VCHANS	(29 * 2 - 1)
+#define DDMA_NR_MAX_VCHANS	21
+#define DMA_NR_MAX_VCHANS	(NDMA_NR_MAX_VCHANS + DDMA_NR_MAX_VCHANS)
+
+/* This set of DDMA timing parameters were found experimentally while
+ * working with the SPI driver and seem to make it behave correctly */
+#define DDMA_MAGIC_SPI_PARAMETERS	(DDMA_PARA_DEST_DATA_BLK_SIZE(1) | \
+					DDMA_PARA_SRC_DATA_BLK_SIZE(1) | \
+					DDMA_PARA_DEST_WAIT_CYCLES(2) | \
+					DDMA_PARA_SRC_WAIT_CYCLES(2))
+
+struct sun4i_dma_pchan {
+	/* Register base of channel */
+	void __iomem			*base;
+	/* vchan currently being serviced */
+	struct sun4i_dma_vchan		*vchan;
+	/* Is this a dedicated pchan? */
+	int				is_dedicated;
+};
+
+struct sun4i_dma_vchan {
+	struct virt_dma_chan		vc;
+	struct dma_slave_config		cfg;
+	struct sun4i_dma_pchan		*pchan;
+	struct sun4i_dma_promise	*processing;
+	struct sun4i_dma_contract	*contract;
+	u8				endpoint;
+	int				is_dedicated;
+};
+
+struct sun4i_dma_promise {
+	u32				cfg;
+	u32				para;
+	dma_addr_t			src;
+	dma_addr_t			dst;
+	size_t				len;
+	struct list_head		list;
+};
+
+/* A contract is a set of promises */
+struct sun4i_dma_contract {
+	struct virt_dma_desc		vd;
+	struct list_head		demands;
+	struct list_head		completed_demands;
+};
+
+struct sun4i_dma_dev {
+	DECLARE_BITMAP(pchans_used, DMA_NR_MAX_CHANNELS);
+	struct dma_device		slave;
+	struct sun4i_dma_pchan		*pchans;
+	struct sun4i_dma_vchan		*vchans;
+	void __iomem			*base;
+	struct clk			*clk;
+	int				irq;
+	spinlock_t			lock;
+};
+
+static struct sun4i_dma_dev *to_sun4i_dma_dev(struct dma_device *dev)
+{
+	return container_of(dev, struct sun4i_dma_dev, slave);
+}
+
+static struct sun4i_dma_vchan *to_sun4i_dma_vchan(struct dma_chan *chan)
+{
+	return container_of(chan, struct sun4i_dma_vchan, vc.chan);
+}
+
+static struct sun4i_dma_contract *to_sun4i_dma_contract(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct sun4i_dma_contract, vd);
+}
+
+static struct device *chan2dev(struct dma_chan *chan)
+{
+	return &chan->dev->device;
+}
+
+static int convert_burst(u32 maxburst)
+{
+	if (maxburst > 8)
+		return -EINVAL;
+
+	/* 1 -> 0, 4 -> 1, 8 -> 2 */
+	return (maxburst >> 2);
+}
+
+static int convert_buswidth(enum dma_slave_buswidth addr_width)
+{
+	if (addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES)
+		return -EINVAL;
+
+	/* 8 (1 byte) -> 0, 16 (2 bytes) -> 1, 32 (4 bytes) -> 2 */
+	return (addr_width >> 1);
+}
+
+static int sun4i_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+	return 0;
+}
+
+static void sun4i_dma_free_chan_resources(struct dma_chan *chan)
+{
+	struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+
+	vchan_free_chan_resources(&vchan->vc);
+}
+
+static struct sun4i_dma_pchan *find_and_use_pchan(struct sun4i_dma_dev *priv,
+						  struct sun4i_dma_vchan *vchan)
+{
+	struct sun4i_dma_pchan *pchan = NULL, *pchans = priv->pchans;
+	unsigned long flags;
+	int i, max;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	/*
+	 * pchans 0-NDMA_NR_MAX_CHANNELS are normal, and
+	 * NDMA_NR_MAX_CHANNELS+ are dedicated ones
+	 */
+	if (vchan->is_dedicated) {
+		i = NDMA_NR_MAX_CHANNELS;
+		max = DMA_NR_MAX_CHANNELS;
+	} else {
+		i = 0;
+		max = NDMA_NR_MAX_CHANNELS;
+	}
+
+	for_each_clear_bit_from(i, &priv->pchans_used, max) {
+		pchan = &pchans[i];
+		pchan->vchan = vchan;
+		set_bit(i, priv->pchans_used);
+		break;
+	}
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return pchan;
+}
+
+static void release_pchan(struct sun4i_dma_dev *priv,
+			  struct sun4i_dma_pchan *pchan)
+{
+	unsigned long flags;
+	int nr = pchan - priv->pchans;
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	clear_bit(nr, priv->pchans_used);
+	pchan->vchan = NULL;
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static void configure_pchan(struct sun4i_dma_pchan *pchan,
+			    struct sun4i_dma_promise *d)
+{
+	/*
+	 * Configure addresses and misc parameters depending on type
+	 * DDMA has an extra field with timing parameters
+	 */
+	if (pchan->is_dedicated) {
+		writel_relaxed(d->src, pchan->base + DDMA_SRC_ADDR_REG);
+		writel_relaxed(d->dst, pchan->base + DDMA_DEST_ADDR_REG);
+		writel_relaxed(d->len, pchan->base + DDMA_BYTE_COUNT_REG);
+		writel_relaxed(d->para, pchan->base + DDMA_PARA_REG);
+		writel_relaxed(d->cfg, pchan->base + DDMA_CFG_REG);
+	} else {
+		writel_relaxed(d->src, pchan->base + NDMA_SRC_ADDR_REG);
+		writel_relaxed(d->dst, pchan->base + NDMA_DEST_ADDR_REG);
+		writel_relaxed(d->len, pchan->base + NDMA_BYTE_COUNT_REG);
+		writel_relaxed(d->cfg, pchan->base + NDMA_CFG_REG);
+	}
+}
+
+static void set_pchan_interrupt(struct sun4i_dma_dev *priv,
+				struct sun4i_dma_pchan *pchan,
+				int half, int end)
+{
+	u32 reg = readl_relaxed(priv->base + DMA_IRQ_ENABLE_REG);
+	int pchan_number = pchan - priv->pchans;
+
+	if (half)

drivers/dma/sun4i-dma.c new file +208 -0

+}
+
+static int execute_vchan_pending(struct sun4i_dma_dev *priv,
+				 struct sun4i_dma_vchan *vchan)
+{
+	struct sun4i_dma_promise *promise = NULL;
+	struct sun4i_dma_contract *contract = NULL;
+	struct sun4i_dma_pchan *pchan;
+	struct virt_dma_desc *vd;
+	int ret;
+
+	lockdep_assert_held(&vchan->vc.lock);
+
+	/* We need a pchan to do anything, so secure one if available */
+	pchan = find_and_use_pchan(priv, vchan);
+	if (!pchan)
+		return -EBUSY;
+
+	/*
+	 * Channel endpoints must not be repeated, so if this vchan
+	 * has already submitted some work, we can't do anything else
+	 */
+	if (vchan->processing) {
+		dev_dbg(chan2dev(&vchan->vc.chan),
+			"processing something to this endpoint already\n");
+		ret = -EBUSY;
+		goto release_pchan;
+	}
+
+	do {
+		/* Figure out which contract we're working with today */
+		vd = vchan_next_desc(&vchan->vc);
+		if (!vd) {
+			dev_dbg(chan2dev(&vchan->vc.chan),
+				"No pending contract found");
+			ret = 0;
+			goto release_pchan;
+		}
+
+		contract = to_sun4i_dma_contract(vd);
+		if (list_empty(&contract->demands)) {
+			/* The contract has been completed so mark it as such */
+			list_del(&contract->vd.node);
+			vchan_cookie_complete(&contract->vd);
+			dev_dbg(chan2dev(&vchan->vc.chan),
+				"Empty contract found and marked complete");
+		}
+	} while (list_empty(&contract->demands));
+
+	/* Now find out what we need to do */
+	promise = list_first_entry(&contract->demands,
+				   struct sun4i_dma_promise, list);
+	vchan->processing = promise;
+
+	/* ... and make it reality */
+	if (promise) {
+		vchan->contract = contract;
+		set_pchan_interrupt(priv, pchan, 0, 1);
+		configure_pchan(pchan, promise);
+	}
+
+	return 0;
+
+release_pchan:
+	release_pchan(priv, pchan);
+	return ret;
+}
+
+/**
+ * Generate a promise, to be used in a normal DMA contract.
+ *
+ * A NDMA promise contains all the information required to program the
+ * normal part of the DMA Engine and get data copied. A non-executed
+ * promise will live in the demands list on a contract. Once it has been
+ * completed, it will be moved to the completed demands list for later freeing.
+ * All linked promises will be freed when the corresponding contract is freed
+ */
+static struct sun4i_dma_promise *
+generate_ndma_promise(struct dma_chan *chan, dma_addr_t src, dma_addr_t dest,
+		      size_t len, struct dma_slave_config *sconfig)
+{
+	struct sun4i_dma_promise *promise;
+	int ret;
+
+	promise = kzalloc(sizeof(*promise), GFP_NOWAIT);
+	if (!promise)
+		return NULL;
+
+	promise->src = src;
+	promise->dst = dest;
+	promise->len = len;
+	promise->cfg = NDMA_CFG_LOADING | NDMA_CFG_BYTE_COUNT_MODE_REMAIN;
+
+	/* Source burst */
+	ret = convert_burst(sconfig->src_maxburst);
+	if (IS_ERR_VALUE(ret))
+		goto fail;
+	promise->cfg |= NDMA_CFG_SRC_BURST_LENGTH(ret);
+
+	/* Destination burst */
+	ret = convert_burst(sconfig->dst_maxburst);
+	if (IS_ERR_VALUE(ret))
+		goto fail;
+	promise->cfg |= NDMA_CFG_DEST_BURST_LENGTH(ret);
+
+	/* Source bus width */
+	ret = convert_buswidth(sconfig->src_addr_width);
+	if (IS_ERR_VALUE(ret))
+		goto fail;
+	promise->cfg |= NDMA_CFG_SRC_DATA_WIDTH(ret);
+
+	/* Destination bus width */
+	ret = convert_buswidth(sconfig->dst_addr_width);
+	if (IS_ERR_VALUE(ret))
+		goto fail;
+	promise->cfg |= NDMA_CFG_DEST_DATA_WIDTH(ret);
+
+	return promise;
+
+fail:
+	kfree(promise);
+	return NULL;
+}
+
+/**
+ * Generate a promise, to be used in a dedicated DMA contract.
+ *
+ * A DDMA promise contains all the information required to program the
+ * Dedicated part of the DMA Engine and get data copied. A non-executed
+ * promise will live in the demands list on a contract. Once it has been
+ * completed, it will be moved to the completed demands list for later freeing.
+ * All linked promises will be freed when the corresponding contract is freed
+ */
+static struct sun4i_dma_promise *
+generate_ddma_promise(struct dma_chan *chan, dma_addr_t src, dma_addr_t dest,
+		      size_t len, struct dma_slave_config *sconfig)
+{
+	struct sun4i_dma_promise *promise;
+	int ret;
+
+	promise = kzalloc(sizeof(*promise), GFP_NOWAIT);
+	if (!promise)
+		return NULL;
+
+	promise->src = src;
+	promise->dst = dest;
+	promise->len = len;
+	promise->cfg = DDMA_CFG_LOADING | DDMA_CFG_BYTE_COUNT_MODE_REMAIN;
+
+	/* Source burst */
+	ret = convert_burst(sconfig->src_maxburst);
+	if (IS_ERR_VALUE(ret))
+		goto fail;
+	promise->cfg |= DDMA_CFG_SRC_BURST_LENGTH(ret);
+
+	/* Destination burst */
+	ret = convert_burst(sconfig->dst_maxburst);
+	if (IS_ERR_VALUE(ret))
+		goto fail;
+	promise->cfg |= DDMA_CFG_DEST_BURST_LENGTH(ret);
+
+	/* Source bus width */
+	ret = convert_buswidth(sconfig->src_addr_width);
+	if (IS_ERR_VALUE(ret))
+		goto fail;
+	promise->cfg |= DDMA_CFG_SRC_DATA_WIDTH(ret);
+
+	/* Destination bus width */
+	ret = convert_buswidth(sconfig->dst_addr_width);
+	if (IS_ERR_VALUE(ret))
+		goto fail;
+	promise->cfg |= DDMA_CFG_DEST_DATA_WIDTH(ret);
+
+	return promise;
+
+fail:
+	kfree(promise);
+	return NULL;
+}
+
+/**
+ * Generate a contract
+ *
+ * Contracts function as DMA descriptors. As our hardware does not support
+ * linked lists, we need to implement SG via software. We use a contract
+ * to hold all the pieces of the request and process them serially one
+ * after another. Each piece is represented as a promise.
+ */
+static struct sun4i_dma_contract *generate_dma_contract(void)
+{
+	struct sun4i_dma_contract *contract;
+
+	contract = kzalloc(sizeof(*contract), GFP_NOWAIT);
+	if (!contract)
+		return NULL;
+
+	INIT_LIST_HEAD(&contract->demands);
+	INIT_LIST_HEAD(&contract->completed_demands);
+
+	return contract;
+}
+
+/**
+ * Free a contract and all its associated promises
+ */
+static void sun4i_dma_free_contract(struct virt_dma_desc *vd)
+{
+	struct sun4i_dma_contract *contract = to_sun4i_dma_contract(vd);

drivers/dma/sun4i-dma.c new file +91 -0

+	kfree(contract);
+}
+
+static struct dma_async_tx_descriptor *
+sun4i_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest,
+			  dma_addr_t src, size_t len, unsigned long flags)
+{
+	struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+	struct dma_slave_config *sconfig = &vchan->cfg;
+	struct sun4i_dma_promise *promise;
+	struct sun4i_dma_contract *contract;
+
+	contract = generate_dma_contract();
+	if (!contract)
+		return NULL;
+
+	if (vchan->is_dedicated)
+		promise = generate_ddma_promise(chan, src, dest, len, sconfig);
+	else
+		promise = generate_ndma_promise(chan, src, dest, len, sconfig);
+
+	if (!promise) {
+		kfree(contract);
+		return NULL;
+	}
+
+	/* Configure memcpy mode */
+	if (vchan->is_dedicated) {
+		promise->cfg |= DDMA_CFG_SRC_DRQ_TYPE(DDMA_DRQ_TYPE_SDRAM) |
+				DDMA_CFG_DEST_DRQ_TYPE(DDMA_DRQ_TYPE_SDRAM);
+	} else {
+		promise->cfg |= NDMA_CFG_SRC_DRQ_TYPE(NDMA_DRQ_TYPE_SDRAM) |
+				NDMA_CFG_DEST_DRQ_TYPE(NDMA_DRQ_TYPE_SDRAM);
+	}
+
+	/* Fill the contract with our only promise */
+	list_add_tail(&promise->list, &contract->demands);
+
+	/* And add it to the vchan */
+	return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
+}
+
+static struct dma_async_tx_descriptor *
+sun4i_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+			unsigned int sg_len, enum dma_transfer_direction dir,
+			unsigned long flags, void *context)
+{
+	struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+	struct dma_slave_config *sconfig = &vchan->cfg;
+	struct sun4i_dma_promise *promise;
+	struct sun4i_dma_contract *contract;
+	struct scatterlist *sg;
+	dma_addr_t srcaddr, dstaddr;
+	u32 endpoints, para;
+	int i;
+
+	if (!sgl)
+		return NULL;
+
+	if (!is_slave_direction(dir)) {
+		dev_err(chan2dev(chan), "Invalid DMA direction\n");
+		return NULL;
+	}
+
+	contract = generate_dma_contract();
+	if (!contract)
+		return NULL;
+
+	/* Figure out endpoints */
+	if (vchan->is_dedicated && dir == DMA_MEM_TO_DEV) {
+		endpoints = DDMA_CFG_SRC_DRQ_TYPE(DDMA_DRQ_TYPE_SDRAM) |
+			    DDMA_CFG_SRC_ADDR_MODE(DDMA_ADDR_MODE_LINEAR) |
+			    DDMA_CFG_DEST_DRQ_TYPE(vchan->endpoint) |
+			    DDMA_CFG_DEST_ADDR_MODE(DDMA_ADDR_MODE_IO);
+	} else if (!vchan->is_dedicated && dir == DMA_MEM_TO_DEV) {
+		endpoints = NDMA_CFG_SRC_DRQ_TYPE(NDMA_DRQ_TYPE_SDRAM) |
+			    NDMA_CFG_DEST_DRQ_TYPE(vchan->endpoint) |
+			    NDMA_CFG_DEST_FIXED_ADDR;
+	} else if (vchan->is_dedicated) {
+		endpoints = DDMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
+			    DDMA_CFG_SRC_ADDR_MODE(DDMA_ADDR_MODE_IO) |
+			    DDMA_CFG_DEST_DRQ_TYPE(DDMA_DRQ_TYPE_SDRAM) |
+			    DDMA_CFG_DEST_ADDR_MODE(DDMA_ADDR_MODE_LINEAR);
+	} else {
+		endpoints = NDMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
+			    NDMA_CFG_SRC_FIXED_ADDR |
+			    NDMA_CFG_DEST_DRQ_TYPE(NDMA_DRQ_TYPE_SDRAM);
+	}
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		/* Figure out addresses */

drivers/dma/sun4i-dma.c new file +118 -0

+
+		promise->cfg |= endpoints;
+		promise->para = para;
+
+		/* Then add it to the contract */
+		list_add_tail(&promise->list, &contract->demands);
+	}
+
+	/*
+	 * Once we've got all the promises ready, add the contract
+	 * to the pending list on the vchan
+	 */
+	return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
+}
+
+static int sun4i_dma_terminate_all(struct sun4i_dma_vchan *vchan)
+{
+	struct sun4i_dma_pchan *pchan = vchan->pchan;
+	LIST_HEAD(head);
+	unsigned long flags, timeout;
+	u32 d_busy = DDMA_CFG_LOADING | DDMA_CFG_BUSY;
+	u32 n_busy = NDMA_CFG_LOADING;
+
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+	vchan_get_all_descriptors(&vchan->vc, &head);
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+	/* If this vchan is operating, wait until it's no longer busy */
+	if (pchan) {
+		timeout = jiffies + msecs_to_jiffies(2000);
+		if (pchan->is_dedicated) {
+			while (readl(pchan->base + DDMA_CFG_REG) & d_busy)
+				if (time_after(jiffies, timeout))
+					return -ETIMEDOUT;
+		} else {
+			while (readl(pchan->base + NDMA_CFG_REG) & n_busy)
+				if (time_after(jiffies, timeout))
+					return -ETIMEDOUT;
+		}
+	}
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+	vchan_dma_desc_free_list(&vchan->vc, &head);
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+	return 0;
+}
+
+static int sun4i_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+			     unsigned long arg)
+{
+	struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+	int ret = 0;
+
+	switch (cmd) {
+	case DMA_RESUME:
+	case DMA_PAUSE:
+		ret = -EINVAL;
+		break;
+
+	case DMA_TERMINATE_ALL:
+		dev_dbg(chan2dev(chan), "Terminating everything on channel\n");
+		ret = sun4i_dma_terminate_all(vchan);
+		break;
+
+	case DMA_SLAVE_CONFIG:
+		memcpy(&vchan->cfg, (void *)arg, sizeof(vchan->cfg));
+		break;
+
+	default:
+		ret = -ENXIO;
+		break;
+	}
+
+	return ret;
+}
+
+static struct dma_chan *sun4i_dma_of_xlate(struct of_phandle_args *dma_spec,
+					   struct of_dma *ofdma)
+{
+	struct sun4i_dma_dev *priv = ofdma->of_dma_data;
+	struct sun4i_dma_vchan *vchan;
+	struct dma_chan *chan;
+	u8 is_dedicated = dma_spec->args[0];
+	u8 endpoint = dma_spec->args[1];
+
+	/* Check if type is Normal or Dedicated */
+	if (is_dedicated != 0 && is_dedicated != 1)
+		return NULL;
+
+	/* Make sure the endpoint looks sane */
+	if ((is_dedicated && endpoint >= DDMA_DRQ_TYPE_LIMIT) ||
+	    (!is_dedicated && endpoint >= NDMA_DRQ_TYPE_LIMIT))
+		return NULL;
+
+	chan = dma_get_any_slave_channel(&priv->slave);
+	if (!chan)
+		return NULL;
+
+	/* Assign the endpoint to the vchan */
+	vchan = to_sun4i_dma_vchan(chan);
+	vchan->is_dedicated = is_dedicated;
+	vchan->endpoint = endpoint;
+
+	return chan;
+}
+
+static enum dma_status sun4i_dma_tx_status(struct dma_chan *chan,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *state)
+{
+	struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+	struct sun4i_dma_pchan *pchan = vchan->pchan;
+	struct sun4i_dma_contract *contract;
+	struct sun4i_dma_promise *promise;
+	struct virt_dma_desc *vd;
+	unsigned long flags;

drivers/dma/sun4i-dma.c new file +250 -0

+	/*
+	 * The hardware is configured to return the remaining byte
+	 * quantity. If possible, replace the first listed element's
+	 * full size with the actual remaining amount
+	 */
+	promise = list_first_entry_or_null(&contract->demands,
+					   struct sun4i_dma_promise, list);
+	if (promise && pchan) {
+		bytes -= promise->len;
+		if (pchan->is_dedicated)
+			bytes += readl(pchan->base + DDMA_BYTE_COUNT_REG);
+		else
+			bytes += readl(pchan->base + NDMA_BYTE_COUNT_REG);
+	}
+
+exit:
+
+	dma_set_residue(state, bytes);
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+	return ret;
+}
+
+static void sun4i_dma_issue_pending(struct dma_chan *chan)
+{
+	struct sun4i_dma_dev *priv = to_sun4i_dma_dev(chan->device);
+	struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+
+	/*
+	 * If there are pending transactions for this vchan, push one of
+	 * them into the engine to get the ball rolling.
+	 */
+	if (vchan_issue_pending(&vchan->vc))
+		execute_vchan_pending(priv, vchan);
+
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+}
+
+static irqreturn_t sun4i_dma_interrupt(int irq, void *dev_id)
+{
+	struct sun4i_dma_dev *priv = dev_id;
+	struct sun4i_dma_pchan *pchans = priv->pchans, *pchan;
+	struct sun4i_dma_vchan *vchan;
+	struct sun4i_dma_contract *contract;
+	unsigned long pendirq, irqs;
+	int bit;
+
+	pendirq = readl_relaxed(priv->base + DMA_IRQ_PENDING_STATUS_REG);
+	irqs = readl_relaxed(priv->base + DMA_IRQ_ENABLE_REG);
+
+	for_each_set_bit(bit, &pendirq, 32) {
+		pchan = &pchans[bit >> 1];
+		vchan = pchan->vchan;
+		contract = vchan->contract;
+
+		/*
+		 * Disable the IRQ and free the pchan if it's an end
+		 * interrupt (odd bit)
+		 */
+		if (bit & 1) {
+			spin_lock(&vchan->vc.lock);
+			/*
+			 * Move the promise into the completed list now that
+			 * we're done with it
+			 */
+			list_del(&vchan->processing->list);
+			list_add_tail(&vchan->processing->list, &contract->completed_demands);
+			vchan->processing = NULL;
+			vchan->pchan = NULL;
+			spin_unlock(&vchan->vc.lock);
+
+			irqs &= ~BIT(bit);
+			release_pchan(priv, pchan);
+		}
+	}
+
+	writel_relaxed(irqs, priv->base + DMA_IRQ_ENABLE_REG);
+
+	/* Writing 1 to the pending field will clear the pending interrupt */
+	writel_relaxed(pendirq, priv->base + DMA_IRQ_PENDING_STATUS_REG);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static irqreturn_t sun4i_dma_submit_work(int irq, void *dev_id)
+{
+	struct sun4i_dma_dev *priv = dev_id;
+	struct sun4i_dma_vchan *vchan;
+	int i;
+
+	for (i = 0; i < DMA_NR_MAX_VCHANS; i++) {
+		vchan = &priv->vchans[i];
+		spin_lock_irq(&vchan->vc.lock);
+		execute_vchan_pending(priv, vchan);
+		spin_unlock_irq(&vchan->vc.lock);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int sun4i_dma_probe(struct platform_device *pdev)
+{
+	struct sun4i_dma_dev *priv;
+	struct resource *res;
+	int i, j, ret;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->irq = platform_get_irq(pdev, 0);
+	if (priv->irq < 0) {
+		dev_err(&pdev->dev, "Cannot claim IRQ\n");
+		return priv->irq;
+	}
+
+	priv->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(&pdev->dev, "No clock specified\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	platform_set_drvdata(pdev, priv);
+	spin_lock_init(&priv->lock);
+
+	dma_cap_zero(priv->slave.cap_mask);
+	dma_cap_set(DMA_PRIVATE, priv->slave.cap_mask);
+	dma_cap_set(DMA_MEMCPY, priv->slave.cap_mask);
+	dma_cap_set(DMA_SLAVE, priv->slave.cap_mask);
+
+	INIT_LIST_HEAD(&priv->slave.channels);
+	priv->slave.device_alloc_chan_resources	= sun4i_dma_alloc_chan_resources;
+	priv->slave.device_free_chan_resources	= sun4i_dma_free_chan_resources;
+	priv->slave.device_tx_status		= sun4i_dma_tx_status;
+	priv->slave.device_issue_pending	= sun4i_dma_issue_pending;
+	priv->slave.device_prep_slave_sg	= sun4i_dma_prep_slave_sg;
+	priv->slave.device_prep_dma_memcpy	= sun4i_dma_prep_dma_memcpy;
+	priv->slave.device_control		= sun4i_dma_control;
+	priv->slave.chancnt			= DDMA_NR_MAX_VCHANS;
+
+	priv->slave.dev = &pdev->dev;
+
+	priv->pchans = devm_kcalloc(&pdev->dev, DMA_NR_MAX_CHANNELS,
+				    sizeof(struct sun4i_dma_pchan), GFP_KERNEL);
+	priv->vchans = devm_kcalloc(&pdev->dev, DMA_NR_MAX_VCHANS,
+				    sizeof(struct sun4i_dma_vchan), GFP_KERNEL);
+	if (!priv->vchans || !priv->pchans)
+		return -ENOMEM;
+
+	/*
+	 * [0..NDMA_NR_MAX_CHANNELS) are normal pchans, and
+	 * [NDMA_NR_MAX_CHANNELS..DMA_NR_MAX_CHANNELS) are dedicated ones
+	 */
+	for (i = 0; i < NDMA_NR_MAX_CHANNELS; i++)
+		priv->pchans[i].base = priv->base + NDMA_CHANNEL_REG_BASE(i);
+
+	for (j = 0; i < DMA_NR_MAX_CHANNELS; i++, j++) {
+		priv->pchans[i].base = priv->base + DDMA_CHANNEL_REG_BASE(j);
+		priv->pchans[i].is_dedicated = 1;
+	}
+
+	for (i = 0; i < DMA_NR_MAX_VCHANS; i++) {
+		struct sun4i_dma_vchan *vchan = &priv->vchans[i];
+
+		spin_lock_init(&vchan->vc.lock);
+		vchan->vc.desc_free = sun4i_dma_free_contract;
+		vchan_init(&vchan->vc, &priv->slave);
+	}
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't enable the clock\n");
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, priv->irq,
+					sun4i_dma_interrupt,
+					sun4i_dma_submit_work,
+					0, dev_name(&pdev->dev), priv);
+	if (ret) {
+		dev_err(&pdev->dev, "Cannot request IRQ\n");
+		goto err_clk_disable;
+	}
+
+	ret = dma_async_device_register(&priv->slave);
+	if (ret) {
+		dev_warn(&pdev->dev, "Failed to register DMA engine device\n");
+		goto err_clk_disable;
+	}
+
+	ret = of_dma_controller_register(pdev->dev.of_node, sun4i_dma_of_xlate,
+					 priv);
+	if (ret) {
+		dev_err(&pdev->dev, "of_dma_controller_register failed\n");
+		goto err_dma_unregister;
+	}
+
+	dev_dbg(&pdev->dev, "Successfully probed SUN4I_DMA\n");
+
+	return 0;
+
+err_dma_unregister:
+	dma_async_device_unregister(&priv->slave);
+err_clk_disable:
+	clk_disable_unprepare(priv->clk);
+	return ret;
+}
+
+static int sun4i_dma_remove(struct platform_device *pdev)
+{
+	struct sun4i_dma_dev *priv = platform_get_drvdata(pdev);
+
+	/* Disable IRQ so no more work is scheduled */
+	disable_irq(priv->irq);
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&priv->slave);
+
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static struct of_device_id sun4i_dma_match[] = {
+	{ .compatible = "allwinner,sun4i-a10-dma" },
+	{ /* sentinel */ },
+};
+
+static struct platform_driver sun4i_dma_driver = {
+	.probe	= sun4i_dma_probe,
+	.remove	= sun4i_dma_remove,
+	.driver	= {
+		.name		= "sun4i-dma",
+		.of_match_table	= sun4i_dma_match,
+	},
+};
+
+module_platform_driver(sun4i_dma_driver);
+
+MODULE_DESCRIPTION("Allwinner A10 Dedicated DMA Controller Driver");
+MODULE_AUTHOR("Emilio L?pez <[email protected]>");
+MODULE_LICENSE("GPL");

Signature · 1 line

2.0.1

Quoted 14 lines

This patch adds support for the DMA engine present on Allwinner A10, A13, A10S and A20 SoCs. This engine has two kinds of channels: normal and dedicated. The main difference is in the mode of operation; while a single normal channel may be operating at any given time, dedicated channels may operate simultaneously provided there is no overlap of source or destination.

Hardware documentation can be found on A10 User Manual (section 12), A13 User Manual (section 14) and A20 User Manual (section 1.12)

Signed-off-by Emilio L?pez <[email protected]>

---
(...)

drivers/dma/Kconfig config XILINX_VDMA · line 379

Quoted 2 lines

drivers/dma/Kconfig +2 -0

+config SUN4I_DMA
+	tristate "Allwinner A10/A10S/A13/A20 DMA support"

I'm not that fond of having an exhaustive list here. If some other SoC we didn't thought of or get a new SoC that uses this controller, this list won't be exhaustive anymore, which is even worse.

Just mention the A10.

drivers/dma/Kconfig config XILINX_VDMA · line 380

Quoted 1 line

drivers/dma/Kconfig +1 -0

+	depends on (MACH_SUN4I || MACH_SUN5I || MACH_SUN7I || (COMPILE_TEST && OF && ARM))

This pretty much defeats the purpose of COMPILE_TEST

drivers/dma/Kconfig config XILINX_VDMA · line 383

Quoted 4 lines

drivers/dma/Kconfig +3 -0

+	select DMA_ENGINE
+	select DMA_OF
+	select DMA_VIRTUAL_CHANNELS

I guess you could default to y for the SoCs where it's relevant.

Quoted 5 lines

drivers/dma/Kconfig +4 -0

+	help
+	  Enable support for the DMA controller present in the sun4i,
+	  sun5i and sun7i Allwinner ARM SoCs.
+

drivers/dma/sun4i-dma.c line 29

Quoted 6 lines

drivers/dma/sun4i-dma.c new file +6 -0

+
+/** Normal DMA register values **/
+
+/* Normal DMA source/destination data request type values */
+#define NDMA_DRQ_TYPE_SDRAM			0x16
+#define NDMA_DRQ_TYPE_LIMIT			(0x1F + 1)

Hmmm, I'm unsure what this is about... What is it supposed to do, and how is it different from BIT(5) ?

Quoted 13 lines

drivers/dma/sun4i-dma.c new file +13 -0

+
+static void set_pchan_interrupt(struct sun4i_dma_dev *priv,
+				struct sun4i_dma_pchan *pchan,
+				int half, int end)
+{
+	u32 reg = readl_relaxed(priv->base + DMA_IRQ_ENABLE_REG);
+	int pchan_number = pchan - priv->pchans;
+
+	if (half)
+		reg |= BIT(pchan_number * 2);
+	else
+		reg &= ~BIT(pchan_number * 2);
+

drivers/dma/sun4i-dma.c line 309

Quoted 6 lines

drivers/dma/sun4i-dma.c new file +6 -0

+	if (end)
+		reg |= BIT(pchan_number * 2 + 1);
+	else
+		reg &= ~BIT(pchan_number * 2 + 1);
+
+	writel_relaxed(reg, priv->base + DMA_IRQ_ENABLE_REG);

I don't see any interrupts here.

Is this suppose to be called with a
lock taken? If so, it should be mentionned in some comment.

Quoted 7 lines

drivers/dma/sun4i-dma.c new file +7 -0

+{
+	struct sun4i_dma_contract *contract = to_sun4i_dma_contract(vd);
+	struct sun4i_dma_promise *promise;
+
+	/* Free all the demands and completed demands */
+	list_for_each_entry(promise, &contract->demands, list) {
+		kfree(promise);

drivers/dma/sun4i-dma.c line 527

Quoted 6 lines

drivers/dma/sun4i-dma.c new file +5 -0

+	}
+
+	list_for_each_entry(promise, &contract->completed_demands, list) {
+		kfree(promise);
+	}

Those brackets are useless.

Quoted 7 lines

drivers/dma/sun4i-dma.c new file +7 -0

+	for_each_sg(sgl, sg, sg_len, i) {
+		/* Figure out addresses */
+		if (dir == DMA_MEM_TO_DEV) {
+			srcaddr = sg_dma_address(sg);
+			dstaddr = sconfig->dst_addr;
+		} else {
+			srcaddr = sconfig->src_addr;

drivers/dma/sun4i-dma.c line 629

Quoted 5 lines

drivers/dma/sun4i-dma.c new file +5 -0

+			dstaddr = sg_dma_address(sg);
+		}
+
+		/* TODO: should this be configurable? */
+		para = DDMA_MAGIC_SPI_PARAMETERS;

What is it? Is it supposed to change from one client device to another?

Quoted 5 lines

drivers/dma/sun4i-dma.c new file +5 -0

+
+		/* And make a suitable promise */
+		if (vchan->is_dedicated)
+			promise = generate_ddma_promise(chan, srcaddr, dstaddr,
+							sg_dma_len(sg), sconfig);

drivers/dma/sun4i-dma.c line 640

Quoted 6 lines

drivers/dma/sun4i-dma.c new file +6 -0

+		else
+			promise = generate_ndma_promise(chan, srcaddr, dstaddr,
+							sg_dma_len(sg), sconfig);
+
+		if (!promise)
+			return NULL; /* TODO */

TODO what?

Quoted 14 lines

drivers/dma/sun4i-dma.c new file +14 -0

+static enum dma_status sun4i_dma_tx_status(struct dma_chan *chan,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *state)
+{
+	struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+	struct sun4i_dma_pchan *pchan = vchan->pchan;
+	struct sun4i_dma_contract *contract;
+	struct sun4i_dma_promise *promise;
+	struct virt_dma_desc *vd;
+	unsigned long flags;
+	enum dma_status ret;
+	size_t bytes = 0;
+
+	ret = dma_cookie_status(chan, cookie, state);

drivers/dma/sun4i-dma.c line 768

Quoted 6 lines

drivers/dma/sun4i-dma.c new file +6 -0

+	if (ret == DMA_COMPLETE)
+		return ret;
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+	vd = vchan_find_desc(&vchan->vc, cookie);
+	if (!vd) /* TODO */

TODO what?

drivers/dma/sun4i-dma.c line 774

Quoted 6 lines

drivers/dma/sun4i-dma.c new file +6 -0

+		goto exit;
+	contract = to_sun4i_dma_contract(vd);
+
+	list_for_each_entry(promise, &contract->demands, list) {
+		bytes += promise->len;
+	}

Useless brackets

Quoted 3 lines

drivers/dma/Kconfig config XILINX_VDMA · line 380

Quoted 1 line

drivers/dma/Kconfig +1 -0

+	depends on (MACH_SUN4I || MACH_SUN5I || MACH_SUN7I || (COMPILE_TEST && OF && ARM))

This pretty much defeats the purpose of COMPILE_TEST

QCOM_BAM_DMA does it that way; it's better to get some coverage than none I guess?

Quoted 4 lines

Quoted 4 lines

drivers/dma/Kconfig +4 -0

+	help
+	  Enable support for the DMA controller present in the sun4i,
+	  sun5i and sun7i Allwinner ARM SoCs.
+

(...)

Quoted 9 lines

drivers/dma/sun4i-dma.c line 29

Quoted 6 lines

drivers/dma/sun4i-dma.c new file +6 -0

+
+/** Normal DMA register values **/
+
+/* Normal DMA source/destination data request type values */
+#define NDMA_DRQ_TYPE_SDRAM			0x16
+#define NDMA_DRQ_TYPE_LIMIT			(0x1F + 1)

Hmmm, I'm unsure what this is about... What is it supposed to do, and how is it different from BIT(5) ?

if (val < NDMA_DRQ_TYPE_LIMIT)

	/* valid value */
else
	/* invalid value */

0x1F is the last valid value

Quoted 13 lines

Quoted 13 lines

drivers/dma/sun4i-dma.c new file +13 -0

+
+static void set_pchan_interrupt(struct sun4i_dma_dev *priv,
+				struct sun4i_dma_pchan *pchan,
+				int half, int end)
+{
+	u32 reg = readl_relaxed(priv->base + DMA_IRQ_ENABLE_REG);
+	int pchan_number = pchan - priv->pchans;
+
+	if (half)
+		reg |= BIT(pchan_number * 2);
+	else
+		reg &= ~BIT(pchan_number * 2);
+

Quoted 8 lines

drivers/dma/sun4i-dma.c line 309

Quoted 6 lines

drivers/dma/sun4i-dma.c new file +6 -0

+	if (end)
+		reg |= BIT(pchan_number * 2 + 1);
+	else
+		reg &= ~BIT(pchan_number * 2 + 1);
+
+	writel_relaxed(reg, priv->base + DMA_IRQ_ENABLE_REG);

I don't see any interrupts here.

Hm?

Quoted 7 lines

Quoted 7 lines

drivers/dma/sun4i-dma.c new file +7 -0

+	for_each_sg(sgl, sg, sg_len, i) {
+		/* Figure out addresses */
+		if (dir == DMA_MEM_TO_DEV) {
+			srcaddr = sg_dma_address(sg);
+			dstaddr = sconfig->dst_addr;
+		} else {
+			srcaddr = sconfig->src_addr;

Quoted 8 lines

drivers/dma/sun4i-dma.c line 629

Quoted 5 lines

drivers/dma/sun4i-dma.c new file +5 -0

+			dstaddr = sg_dma_address(sg);
+		}
+
+		/* TODO: should this be configurable? */
+		para = DDMA_MAGIC_SPI_PARAMETERS;

What is it? Is it supposed to change from one client device to another?

These are the magic DMA engine timings that keep SPI going. I haven't seen any interface on DMAEngine to configure timings, and so far they seem to work for everything we support, so I've kept them here. I don't know if other devices need different timings because, as usual, we only have the "para" bitfield meanings, but no comment on what the values should be when doing a certain operation :|

Quoted 14 lines

Quoted 14 lines

drivers/dma/sun4i-dma.c new file +14 -0

+static enum dma_status sun4i_dma_tx_status(struct dma_chan *chan,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *state)
+{
+	struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+	struct sun4i_dma_pchan *pchan = vchan->pchan;
+	struct sun4i_dma_contract *contract;
+	struct sun4i_dma_promise *promise;
+	struct virt_dma_desc *vd;
+	unsigned long flags;
+	enum dma_status ret;
+	size_t bytes = 0;
+
+	ret = dma_cookie_status(chan, cookie, state);

Quoted 9 lines

drivers/dma/sun4i-dma.c line 768

Quoted 6 lines

drivers/dma/sun4i-dma.c new file +6 -0

+	if (ret == DMA_COMPLETE)
+		return ret;
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+	vd = vchan_find_desc(&vchan->vc, cookie);
+	if (!vd) /* TODO */

TODO what?

/* TODO: remove the TODO */

This patch adds DMA support for 64 byte transfers on the sun4i SPI controller. Bigger transfers did not seem to work when tested, and if the hardware actually supports those, it will need further investigation as to how to issue them correctly.

This patch adds DMA support for 64 byte transfers on the sun4i SPI controller. Bigger transfers did not seem to work when tested, and if the hardware actually supports those, it will need further investigation as to how to issue them correctly.

Signed-off-by Emilio L?pez <[email protected]>

Hi Emilio,

Quoted 5 lines · Emilio L?pez

This patch adds DMA support for 64 byte transfers on the sun4i SPI controller. Bigger transfers did not seem to work when tested, and if the hardware actually supports those, it will need further investigation as to how to issue them correctly.

Quoted 1 line

Signed-off-by Emilio L?pez <[email protected]>

This patch looks fine from a quick look, but you should put Mark Brown in the recipients, since he's the SPI maintainer, and will probably have a sharper look.

Let's add a node to represent the A10 DMA controller on the device tree.

Signed-off-by Emilio L?pez <[email protected]>

---
 arch/arm/boot/dts/sun4i-a10.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

arch/arm/boot/dts/sun4i-a10.dtsi +0 -0

index d96e179..f17cbeb 100644

arch/arm/boot/dts/sun4i-a10.dtsi +2 -1

+               };
+
                spi0: spi at 01c05000 {
                        compatible = "allwinner,sun4i-a10-spi";
                        reg = <0x01c05000 0x1000>;
--

2.0.1

The A10S and A13 SoCs have sun4i-compatible DMA controllers. Let's add the corresponding nodes to represent them on the device tree.

Signed-off-by Emilio L?pez <[email protected]>

---

Note that I have only tested on A10S, if anyone with an A13 device could test as well, that would be great!

 arch/arm/boot/dts/sun5i-a10s.dtsi | 8 ++++++++
 arch/arm/boot/dts/sun5i-a13.dtsi  | 8 ++++++++
 2 files changed, 16 insertions(+)

arch/arm/boot/dts/sun5i-a10s.dtsi +8 -0

index b64f705..3708817 100644
@@ -300,6 +300,14 @@
                #size-cells = <1>;
                ranges;
 
+               dma: dma-controller at 01c02000 {
+                       compatible = "allwinner,sun4i-a10-dma";
+                       reg = <0x01c02000 0x1000>;
+                       interrupts = <27>;
+                       clocks = <&ahb_gates 6>;
+                       #dma-cells = <2>;
+               };
+
                spi0: spi at 01c05000 {
                        compatible = "allwinner,sun4i-a10-spi";
                        reg = <0x01c05000 0x1000>;

arch/arm/boot/dts/sun5i-a13.dtsi +0 -0

index 3b2a94c..1f1adf2 100644

arch/arm/boot/dts/sun5i-a13.dtsi +1 -1

+
                spi0: spi at 01c05000 {
                        compatible = "allwinner,sun4i-a10-spi";
                        reg = <0x01c05000 0x1000>;
--

2.0.1

The A20 SoC has a sun4i-compatible DMA controller. Let's add a node to represent it on the device tree.

Signed-off-by Emilio L?pez <[email protected]>

---
 arch/arm/boot/dts/sun7i-a20.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

arch/arm/boot/dts/sun7i-a20.dtsi +0 -0

index 01e9466..8cd3534 100644

arch/arm/boot/dts/sun7i-a20.dtsi +1 -1

+
                spi0: spi at 01c05000 {
                        compatible = "allwinner,sun4i-a10-spi";
                        reg = <0x01c05000 0x1000>;
--

2.0.1

All of our SPI controllers support DMA transfers, so let's add the properties here so they can be used when it's best to do so.

Signed-off-by Emilio L?pez <[email protected]>

---
 arch/arm/boot/dts/sun4i-a10.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

arch/arm/boot/dts/sun4i-a10.dtsi +8 -1

index f17cbeb..56d02af 100644
@@ -353,6 +353,8 @@
                        interrupts = <10>;
                        clocks = <&ahb_gates 20>, <&spi0_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 27>, <&dma 1 26>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -364,6 +366,8 @@
                        interrupts = <11>;
                        clocks = <&ahb_gates 21>, <&spi1_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 9>, <&dma 1 8>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -459,6 +463,8 @@
                        interrupts = <12>;
                        clocks = <&ahb_gates 22>, <&spi2_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 29>, <&dma 1 28>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -498,6 +504,8 @@
                        interrupts = <50>;
                        clocks = <&ahb_gates 23>, <&spi3_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 31>, <&dma 1 30>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;
--

2.0.1

All of our SPI controllers support DMA transfers, so let's add the properties here so they can be used when it's best to do so.

Signed-off-by Emilio L?pez <[email protected]>

---
 arch/arm/boot/dts/sun5i-a10s.dtsi | 6 ++++++
 arch/arm/boot/dts/sun5i-a13.dtsi  | 6 ++++++
 2 files changed, 12 insertions(+)

arch/arm/boot/dts/sun5i-a10s.dtsi +6 -0

index 3708817..12f26f3 100644
@@ -314,6 +314,8 @@
                        interrupts = <10>;
                        clocks = <&ahb_gates 20>, <&spi0_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 27>, <&dma 1 26>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -325,6 +327,8 @@
                        interrupts = <11>;
                        clocks = <&ahb_gates 21>, <&spi1_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 9>, <&dma 1 8>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -411,6 +415,8 @@
                        interrupts = <12>;
                        clocks = <&ahb_gates 22>, <&spi2_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 29>, <&dma 1 28>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

arch/arm/boot/dts/sun5i-a13.dtsi +6 -1

index 1f1adf2..4bbf455 100644
@@ -312,6 +312,8 @@
                        interrupts = <10>;
                        clocks = <&ahb_gates 20>, <&spi0_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 27>, <&dma 1 26>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -323,6 +325,8 @@
                        interrupts = <11>;
                        clocks = <&ahb_gates 21>, <&spi1_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 9>, <&dma 1 8>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -384,6 +388,8 @@
                        interrupts = <12>;
                        clocks = <&ahb_gates 22>, <&spi2_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 29>, <&dma 1 28>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;
--

2.0.1

All of our SPI controllers support DMA transfers, so let's add the properties here so they can be used when it's best to do so.

Signed-off-by Emilio L?pez <[email protected]>

---
 arch/arm/boot/dts/sun7i-a20.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

arch/arm/boot/dts/sun7i-a20.dtsi +8 -1

index 8cd3534..804dc01 100644
@@ -437,6 +437,8 @@
                        interrupts = <0 10 4>;
                        clocks = <&ahb_gates 20>, <&spi0_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 27>, <&dma 1 26>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -448,6 +450,8 @@
                        interrupts = <0 11 4>;
                        clocks = <&ahb_gates 21>, <&spi1_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 9>, <&dma 1 8>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -543,6 +547,8 @@
                        interrupts = <0 12 4>;
                        clocks = <&ahb_gates 22>, <&spi2_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 29>, <&dma 1 28>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;

@@ -582,6 +588,8 @@
                        interrupts = <0 50 4>;
                        clocks = <&ahb_gates 23>, <&spi3_clk>;
                        clock-names = "ahb", "mod";
+                       dmas = <&dma 1 31>, <&dma 1 30>;
+                       dma-names = "rx", "tx";
                        status = "disabled";
                        #address-cells = <1>;
                        #size-cells = <0>;
--

2.0.1

---
  arch/arm/boot/dts/sun7i-a20-cubietruck.dts | 12 ++++++++++++
  1 file changed, 12 insertions(+)

arch/arm/boot/dts/sun7i-a20-cubietruck.dts +0 -0

index b87fea9..4ef421f 100644

Hello.

On 07/06/2014 08:05 AM, Emilio L?pez wrote:

You need to sign off on your patches, else they couldn't be applied.

Hi,

El 06/07/14 12:21, Sergei Shtylyov escribi?:

Quoted 4 lines

Hello.

On 07/06/2014 08:05 AM, Emilio L?pez wrote:

Quoted 1 line

You need to sign off on your patches, else they couldn't be applied.

That's kind of the point here. These patches are just intended for testing. From the cover letter:

"""Patches nine, ten and eleven are *only intended
for testing*, and add a dummy SPIdev device to cubieboard, cubietruck and A10S-OLinuXino to facilitate testing with spidev_test."""

Hi everyone,

As part of Google Summer of Code, I've tasked myself with implementing DMA support for the earlier Allwinner platforms. This second round of patches is the result of said effort.

The first patch is the actual driver to support these platforms. Patches three, four and five add the corresponding DMA node to the sun4i, sun5i and sun7i device trees.

The second patch, involving the sunxi SPI driver, lets users do SPI transfers of >=64 bytes by using DMA. The first round of patches also had a patch for 8250_dw letting it use DMA as well, but there were some issues causing underruns and "too much work for IRQ", so I have dropped them. It's worth noting that Allwinner themselves don't use DMA transfers on their 8250 driver on the SDK.

Patches six, seven and eight add the DMA properties to SPI so the first two patches can be used. Patches nine, ten and eleven are *only intended for testing*, and add a dummy SPIdev device to cubieboard, cubietruck and A10S-OLinuXino to facilitate testing with spidev_test.

My main testing procedure for SPI has been modified versions of spidev_test from the kernel tree, with and without shorting MISO and MOSI. For memory to memory transfers, I have used dmatest.ko with various configurations. I have done testing on a cubieboard (A10, sun4i) and cubietruck (A20, sun7i) as well as an A10S-OLinuXino.

You will find some extra remarks on individual patches after their descriptions. All comments are welcome.

Thanks!

Emilio L?pez (8):
dma: sun4i: Add support for the DMA engine on sun[457]i SoCs
spi: sun4i: add DMA support
ARM: sun4i: Add node to represent the DMA controller
ARM: sun5i: Add nodes to represent the DMA controllers
ARM: sun7i: Add node to represent the DMA controller
ARM: sun4i: enable DMA on SPI
ARM: sun5i: enable DMA on SPI
ARM: sun7i: enable DMA on SPI

 .../devicetree/bindings/dma/sun4i-dma.txt          |   45 +
 arch/arm/boot/dts/sun4i-a10.dtsi                   |   16 +
 arch/arm/boot/dts/sun5i-a10s.dtsi                  |   14 +
 arch/arm/boot/dts/sun5i-a13.dtsi                   |   14 +
 arch/arm/boot/dts/sun7i-a20.dtsi                   |   16 +
 drivers/dma/Kconfig                                |   10 +
 drivers/dma/Makefile                               |    1 +
 drivers/dma/sun4i-dma.c                            | 1025 ++++++++++++++++++++
 drivers/spi/spi-sun4i.c                            |  155 ++-
 9 files changed, 1285 insertions(+), 11 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/sun4i-dma.txt
 create mode 100644 drivers/dma/sun4i-dma.c

--
2.0.1

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