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-rw-r--r--drivers/dma/sun4i-dma.c1310
1 files changed, 1310 insertions, 0 deletions
diff --git a/drivers/dma/sun4i-dma.c b/drivers/dma/sun4i-dma.c
new file mode 100644
index 000000000..f291b1b4d
--- /dev/null
+++ b/drivers/dma/sun4i-dma.c
@@ -0,0 +1,1310 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2014 Emilio López
+ * Emilio López <emilio@elopez.com.ar>
+ */
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/dma-mapping.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>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "virt-dma.h"
+
+/** Common macros to normal and dedicated DMA registers **/
+
+#define SUN4I_DMA_CFG_LOADING BIT(31)
+#define SUN4I_DMA_CFG_DST_DATA_WIDTH(width) ((width) << 25)
+#define SUN4I_DMA_CFG_DST_BURST_LENGTH(len) ((len) << 23)
+#define SUN4I_DMA_CFG_DST_ADDR_MODE(mode) ((mode) << 21)
+#define SUN4I_DMA_CFG_DST_DRQ_TYPE(type) ((type) << 16)
+#define SUN4I_DMA_CFG_SRC_DATA_WIDTH(width) ((width) << 9)
+#define SUN4I_DMA_CFG_SRC_BURST_LENGTH(len) ((len) << 7)
+#define SUN4I_DMA_CFG_SRC_ADDR_MODE(mode) ((mode) << 5)
+#define SUN4I_DMA_CFG_SRC_DRQ_TYPE(type) (type)
+
+/** Normal DMA register values **/
+
+/* Normal DMA source/destination data request type values */
+#define SUN4I_NDMA_DRQ_TYPE_SDRAM 0x16
+#define SUN4I_NDMA_DRQ_TYPE_LIMIT (0x1F + 1)
+
+/** Normal DMA register layout **/
+
+/* Dedicated DMA source/destination address mode values */
+#define SUN4I_NDMA_ADDR_MODE_LINEAR 0
+#define SUN4I_NDMA_ADDR_MODE_IO 1
+
+/* Normal DMA configuration register layout */
+#define SUN4I_NDMA_CFG_CONT_MODE BIT(30)
+#define SUN4I_NDMA_CFG_WAIT_STATE(n) ((n) << 27)
+#define SUN4I_NDMA_CFG_DST_NON_SECURE BIT(22)
+#define SUN4I_NDMA_CFG_BYTE_COUNT_MODE_REMAIN BIT(15)
+#define SUN4I_NDMA_CFG_SRC_NON_SECURE BIT(6)
+
+/** Dedicated DMA register values **/
+
+/* Dedicated DMA source/destination address mode values */
+#define SUN4I_DDMA_ADDR_MODE_LINEAR 0
+#define SUN4I_DDMA_ADDR_MODE_IO 1
+#define SUN4I_DDMA_ADDR_MODE_HORIZONTAL_PAGE 2
+#define SUN4I_DDMA_ADDR_MODE_VERTICAL_PAGE 3
+
+/* Dedicated DMA source/destination data request type values */
+#define SUN4I_DDMA_DRQ_TYPE_SDRAM 0x1
+#define SUN4I_DDMA_DRQ_TYPE_LIMIT (0x1F + 1)
+
+/** Dedicated DMA register layout **/
+
+/* Dedicated DMA configuration register layout */
+#define SUN4I_DDMA_CFG_BUSY BIT(30)
+#define SUN4I_DDMA_CFG_CONT_MODE BIT(29)
+#define SUN4I_DDMA_CFG_DST_NON_SECURE BIT(28)
+#define SUN4I_DDMA_CFG_BYTE_COUNT_MODE_REMAIN BIT(15)
+#define SUN4I_DDMA_CFG_SRC_NON_SECURE BIT(12)
+
+/* Dedicated DMA parameter register layout */
+#define SUN4I_DDMA_PARA_DST_DATA_BLK_SIZE(n) (((n) - 1) << 24)
+#define SUN4I_DDMA_PARA_DST_WAIT_CYCLES(n) (((n) - 1) << 16)
+#define SUN4I_DDMA_PARA_SRC_DATA_BLK_SIZE(n) (((n) - 1) << 8)
+#define SUN4I_DDMA_PARA_SRC_WAIT_CYCLES(n) (((n) - 1) << 0)
+
+/** DMA register offsets **/
+
+/* General register offsets */
+#define SUN4I_DMA_IRQ_ENABLE_REG 0x0
+#define SUN4I_DMA_IRQ_PENDING_STATUS_REG 0x4
+
+/* Normal DMA register offsets */
+#define SUN4I_NDMA_CHANNEL_REG_BASE(n) (0x100 + (n) * 0x20)
+#define SUN4I_NDMA_CFG_REG 0x0
+#define SUN4I_NDMA_SRC_ADDR_REG 0x4
+#define SUN4I_NDMA_DST_ADDR_REG 0x8
+#define SUN4I_NDMA_BYTE_COUNT_REG 0xC
+
+/* Dedicated DMA register offsets */
+#define SUN4I_DDMA_CHANNEL_REG_BASE(n) (0x300 + (n) * 0x20)
+#define SUN4I_DDMA_CFG_REG 0x0
+#define SUN4I_DDMA_SRC_ADDR_REG 0x4
+#define SUN4I_DDMA_DST_ADDR_REG 0x8
+#define SUN4I_DDMA_BYTE_COUNT_REG 0xC
+#define SUN4I_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 SUN4I_NDMA_NR_MAX_CHANNELS 8
+#define SUN4I_DDMA_NR_MAX_CHANNELS 8
+#define SUN4I_DMA_NR_MAX_CHANNELS \
+ (SUN4I_NDMA_NR_MAX_CHANNELS + SUN4I_DDMA_NR_MAX_CHANNELS)
+#define SUN4I_NDMA_NR_MAX_VCHANS (29 * 2 - 1)
+#define SUN4I_DDMA_NR_MAX_VCHANS 21
+#define SUN4I_DMA_NR_MAX_VCHANS \
+ (SUN4I_NDMA_NR_MAX_VCHANS + SUN4I_DDMA_NR_MAX_VCHANS)
+
+/* This set of SUN4I_DDMA timing parameters were found experimentally while
+ * working with the SPI driver and seem to make it behave correctly */
+#define SUN4I_DDMA_MAGIC_SPI_PARAMETERS \
+ (SUN4I_DDMA_PARA_DST_DATA_BLK_SIZE(1) | \
+ SUN4I_DDMA_PARA_SRC_DATA_BLK_SIZE(1) | \
+ SUN4I_DDMA_PARA_DST_WAIT_CYCLES(2) | \
+ SUN4I_DDMA_PARA_SRC_WAIT_CYCLES(2))
+
+/*
+ * Normal DMA supports individual transfers (segments) up to 128k.
+ * Dedicated DMA supports transfers up to 16M. We can only report
+ * one size limit, so we have to use the smaller value.
+ */
+#define SUN4I_NDMA_MAX_SEG_SIZE SZ_128K
+#define SUN4I_DDMA_MAX_SEG_SIZE SZ_16M
+#define SUN4I_DMA_MAX_SEG_SIZE SUN4I_NDMA_MAX_SEG_SIZE
+
+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;
+ bool is_cyclic : 1;
+ bool use_half_int : 1;
+};
+
+struct sun4i_dma_dev {
+ DECLARE_BITMAP(pchans_used, SUN4I_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 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;
+
+ /*
+ * pchans 0-SUN4I_NDMA_NR_MAX_CHANNELS are normal, and
+ * SUN4I_NDMA_NR_MAX_CHANNELS+ are dedicated ones
+ */
+ if (vchan->is_dedicated) {
+ i = SUN4I_NDMA_NR_MAX_CHANNELS;
+ max = SUN4I_DMA_NR_MAX_CHANNELS;
+ } else {
+ i = 0;
+ max = SUN4I_NDMA_NR_MAX_CHANNELS;
+ }
+
+ spin_lock_irqsave(&priv->lock, flags);
+ 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);
+
+ pchan->vchan = NULL;
+ clear_bit(nr, priv->pchans_used);
+
+ 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
+ * SUN4I_DDMA has an extra field with timing parameters
+ */
+ if (pchan->is_dedicated) {
+ writel_relaxed(d->src, pchan->base + SUN4I_DDMA_SRC_ADDR_REG);
+ writel_relaxed(d->dst, pchan->base + SUN4I_DDMA_DST_ADDR_REG);
+ writel_relaxed(d->len, pchan->base + SUN4I_DDMA_BYTE_COUNT_REG);
+ writel_relaxed(d->para, pchan->base + SUN4I_DDMA_PARA_REG);
+ writel_relaxed(d->cfg, pchan->base + SUN4I_DDMA_CFG_REG);
+ } else {
+ writel_relaxed(d->src, pchan->base + SUN4I_NDMA_SRC_ADDR_REG);
+ writel_relaxed(d->dst, pchan->base + SUN4I_NDMA_DST_ADDR_REG);
+ writel_relaxed(d->len, pchan->base + SUN4I_NDMA_BYTE_COUNT_REG);
+ writel_relaxed(d->cfg, pchan->base + SUN4I_NDMA_CFG_REG);
+ }
+}
+
+static void set_pchan_interrupt(struct sun4i_dma_dev *priv,
+ struct sun4i_dma_pchan *pchan,
+ int half, int end)
+{
+ u32 reg;
+ int pchan_number = pchan - priv->pchans;
+ unsigned long flags;
+
+ spin_lock_irqsave(&priv->lock, flags);
+
+ reg = readl_relaxed(priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
+
+ if (half)
+ reg |= BIT(pchan_number * 2);
+ else
+ reg &= ~BIT(pchan_number * 2);
+
+ if (end)
+ reg |= BIT(pchan_number * 2 + 1);
+ else
+ reg &= ~BIT(pchan_number * 2 + 1);
+
+ writel_relaxed(reg, priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
+
+ spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+/*
+ * Execute pending operations on a vchan
+ *
+ * When given a vchan, this function will try to acquire a suitable
+ * pchan and, if successful, will configure it to fulfill a promise
+ * from the next pending contract.
+ *
+ * This function must be called with &vchan->vc.lock held.
+ */
+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;
+ vchan->pchan = pchan;
+ set_pchan_interrupt(priv, pchan, contract->use_half_int, 1);
+ configure_pchan(pchan, promise);
+ }
+
+ return 0;
+
+release_pchan:
+ release_pchan(priv, pchan);
+ return ret;
+}
+
+static int sanitize_config(struct dma_slave_config *sconfig,
+ enum dma_transfer_direction direction)
+{
+ switch (direction) {
+ case DMA_MEM_TO_DEV:
+ if ((sconfig->dst_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) ||
+ !sconfig->dst_maxburst)
+ return -EINVAL;
+
+ if (sconfig->src_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
+ sconfig->src_addr_width = sconfig->dst_addr_width;
+
+ if (!sconfig->src_maxburst)
+ sconfig->src_maxburst = sconfig->dst_maxburst;
+
+ break;
+
+ case DMA_DEV_TO_MEM:
+ if ((sconfig->src_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) ||
+ !sconfig->src_maxburst)
+ return -EINVAL;
+
+ if (sconfig->dst_addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED)
+ sconfig->dst_addr_width = sconfig->src_addr_width;
+
+ if (!sconfig->dst_maxburst)
+ sconfig->dst_maxburst = sconfig->src_maxburst;
+
+ break;
+ default:
+ return 0;
+ }
+
+ return 0;
+}
+
+/*
+ * 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,
+ enum dma_transfer_direction direction)
+{
+ struct sun4i_dma_promise *promise;
+ int ret;
+
+ ret = sanitize_config(sconfig, direction);
+ if (ret)
+ return NULL;
+
+ promise = kzalloc(sizeof(*promise), GFP_NOWAIT);
+ if (!promise)
+ return NULL;
+
+ promise->src = src;
+ promise->dst = dest;
+ promise->len = len;
+ promise->cfg = SUN4I_DMA_CFG_LOADING |
+ SUN4I_NDMA_CFG_BYTE_COUNT_MODE_REMAIN;
+
+ dev_dbg(chan2dev(chan),
+ "src burst %d, dst burst %d, src buswidth %d, dst buswidth %d",
+ sconfig->src_maxburst, sconfig->dst_maxburst,
+ sconfig->src_addr_width, sconfig->dst_addr_width);
+
+ /* Source burst */
+ ret = convert_burst(sconfig->src_maxburst);
+ if (ret < 0)
+ goto fail;
+ promise->cfg |= SUN4I_DMA_CFG_SRC_BURST_LENGTH(ret);
+
+ /* Destination burst */
+ ret = convert_burst(sconfig->dst_maxburst);
+ if (ret < 0)
+ goto fail;
+ promise->cfg |= SUN4I_DMA_CFG_DST_BURST_LENGTH(ret);
+
+ /* Source bus width */
+ ret = convert_buswidth(sconfig->src_addr_width);
+ if (ret < 0)
+ goto fail;
+ promise->cfg |= SUN4I_DMA_CFG_SRC_DATA_WIDTH(ret);
+
+ /* Destination bus width */
+ ret = convert_buswidth(sconfig->dst_addr_width);
+ if (ret < 0)
+ goto fail;
+ promise->cfg |= SUN4I_DMA_CFG_DST_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 = SUN4I_DMA_CFG_LOADING |
+ SUN4I_DDMA_CFG_BYTE_COUNT_MODE_REMAIN;
+
+ /* Source burst */
+ ret = convert_burst(sconfig->src_maxburst);
+ if (ret < 0)
+ goto fail;
+ promise->cfg |= SUN4I_DMA_CFG_SRC_BURST_LENGTH(ret);
+
+ /* Destination burst */
+ ret = convert_burst(sconfig->dst_maxburst);
+ if (ret < 0)
+ goto fail;
+ promise->cfg |= SUN4I_DMA_CFG_DST_BURST_LENGTH(ret);
+
+ /* Source bus width */
+ ret = convert_buswidth(sconfig->src_addr_width);
+ if (ret < 0)
+ goto fail;
+ promise->cfg |= SUN4I_DMA_CFG_SRC_DATA_WIDTH(ret);
+
+ /* Destination bus width */
+ ret = convert_buswidth(sconfig->dst_addr_width);
+ if (ret < 0)
+ goto fail;
+ promise->cfg |= SUN4I_DMA_CFG_DST_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;
+}
+
+/*
+ * Get next promise on a cyclic transfer
+ *
+ * Cyclic contracts contain a series of promises which are executed on a
+ * loop. This function returns the next promise from a cyclic contract,
+ * so it can be programmed into the hardware.
+ */
+static struct sun4i_dma_promise *
+get_next_cyclic_promise(struct sun4i_dma_contract *contract)
+{
+ struct sun4i_dma_promise *promise;
+
+ promise = list_first_entry_or_null(&contract->demands,
+ struct sun4i_dma_promise, list);
+ if (!promise) {
+ list_splice_init(&contract->completed_demands,
+ &contract->demands);
+ promise = list_first_entry(&contract->demands,
+ struct sun4i_dma_promise, list);
+ }
+
+ return promise;
+}
+
+/*
+ * 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);
+ struct sun4i_dma_promise *promise, *tmp;
+
+ /* Free all the demands and completed demands */
+ list_for_each_entry_safe(promise, tmp, &contract->demands, list)
+ kfree(promise);
+
+ list_for_each_entry_safe(promise, tmp, &contract->completed_demands, list)
+ kfree(promise);
+
+ 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;
+
+ /*
+ * We can only do the copy to bus aligned addresses, so
+ * choose the best one so we get decent performance. We also
+ * maximize the burst size for this same reason.
+ */
+ sconfig->src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ sconfig->dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+ sconfig->src_maxburst = 8;
+ sconfig->dst_maxburst = 8;
+
+ if (vchan->is_dedicated)
+ promise = generate_ddma_promise(chan, src, dest, len, sconfig);
+ else
+ promise = generate_ndma_promise(chan, src, dest, len, sconfig,
+ DMA_MEM_TO_MEM);
+
+ if (!promise) {
+ kfree(contract);
+ return NULL;
+ }
+
+ /* Configure memcpy mode */
+ if (vchan->is_dedicated) {
+ promise->cfg |= SUN4I_DMA_CFG_SRC_DRQ_TYPE(SUN4I_DDMA_DRQ_TYPE_SDRAM) |
+ SUN4I_DMA_CFG_DST_DRQ_TYPE(SUN4I_DDMA_DRQ_TYPE_SDRAM);
+ } else {
+ promise->cfg |= SUN4I_DMA_CFG_SRC_DRQ_TYPE(SUN4I_NDMA_DRQ_TYPE_SDRAM) |
+ SUN4I_DMA_CFG_DST_DRQ_TYPE(SUN4I_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_dma_cyclic(struct dma_chan *chan, dma_addr_t buf, size_t len,
+ size_t period_len, enum dma_transfer_direction dir,
+ 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;
+ dma_addr_t src, dest;
+ u32 endpoints;
+ int nr_periods, offset, plength, i;
+ u8 ram_type, io_mode, linear_mode;
+
+ if (!is_slave_direction(dir)) {
+ dev_err(chan2dev(chan), "Invalid DMA direction\n");
+ return NULL;
+ }
+
+ contract = generate_dma_contract();
+ if (!contract)
+ return NULL;
+
+ contract->is_cyclic = 1;
+
+ if (vchan->is_dedicated) {
+ io_mode = SUN4I_DDMA_ADDR_MODE_IO;
+ linear_mode = SUN4I_DDMA_ADDR_MODE_LINEAR;
+ ram_type = SUN4I_DDMA_DRQ_TYPE_SDRAM;
+ } else {
+ io_mode = SUN4I_NDMA_ADDR_MODE_IO;
+ linear_mode = SUN4I_NDMA_ADDR_MODE_LINEAR;
+ ram_type = SUN4I_NDMA_DRQ_TYPE_SDRAM;
+ }
+
+ if (dir == DMA_MEM_TO_DEV) {
+ src = buf;
+ dest = sconfig->dst_addr;
+ endpoints = SUN4I_DMA_CFG_DST_DRQ_TYPE(vchan->endpoint) |
+ SUN4I_DMA_CFG_DST_ADDR_MODE(io_mode) |
+ SUN4I_DMA_CFG_SRC_DRQ_TYPE(ram_type) |
+ SUN4I_DMA_CFG_SRC_ADDR_MODE(linear_mode);
+ } else {
+ src = sconfig->src_addr;
+ dest = buf;
+ endpoints = SUN4I_DMA_CFG_DST_DRQ_TYPE(ram_type) |
+ SUN4I_DMA_CFG_DST_ADDR_MODE(linear_mode) |
+ SUN4I_DMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
+ SUN4I_DMA_CFG_SRC_ADDR_MODE(io_mode);
+ }
+
+ /*
+ * We will be using half done interrupts to make two periods
+ * out of a promise, so we need to program the DMA engine less
+ * often
+ */
+
+ /*
+ * The engine can interrupt on half-transfer, so we can use
+ * this feature to program the engine half as often as if we
+ * didn't use it (keep in mind the hardware doesn't support
+ * linked lists).
+ *
+ * Say you have a set of periods (| marks the start/end, I for
+ * interrupt, P for programming the engine to do a new
+ * transfer), the easy but slow way would be to do
+ *
+ * |---|---|---|---| (periods / promises)
+ * P I,P I,P I,P I
+ *
+ * Using half transfer interrupts you can do
+ *
+ * |-------|-------| (promises as configured on hw)
+ * |---|---|---|---| (periods)
+ * P I I,P I I
+ *
+ * Which requires half the engine programming for the same
+ * functionality.
+ *
+ * This only works if two periods fit in a single promise. That will
+ * always be the case for dedicated DMA, where the hardware has a much
+ * larger maximum transfer size than advertised to clients.
+ */
+ if (vchan->is_dedicated || period_len <= SUN4I_NDMA_MAX_SEG_SIZE / 2) {
+ period_len *= 2;
+ contract->use_half_int = 1;
+ }
+
+ nr_periods = DIV_ROUND_UP(len, period_len);
+ for (i = 0; i < nr_periods; i++) {
+ /* Calculate the offset in the buffer and the length needed */
+ offset = i * period_len;
+ plength = min((len - offset), period_len);
+ if (dir == DMA_MEM_TO_DEV)
+ src = buf + offset;
+ else
+ dest = buf + offset;
+
+ /* Make the promise */
+ if (vchan->is_dedicated)
+ promise = generate_ddma_promise(chan, src, dest,
+ plength, sconfig);
+ else
+ promise = generate_ndma_promise(chan, src, dest,
+ plength, sconfig, dir);
+
+ if (!promise) {
+ /* TODO: should we free everything? */
+ return NULL;
+ }
+ promise->cfg |= endpoints;
+
+ /* Then add it to the contract */
+ 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;
+ u8 ram_type, io_mode, linear_mode;
+ 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;
+
+ if (vchan->is_dedicated) {
+ io_mode = SUN4I_DDMA_ADDR_MODE_IO;
+ linear_mode = SUN4I_DDMA_ADDR_MODE_LINEAR;
+ ram_type = SUN4I_DDMA_DRQ_TYPE_SDRAM;
+ } else {
+ io_mode = SUN4I_NDMA_ADDR_MODE_IO;
+ linear_mode = SUN4I_NDMA_ADDR_MODE_LINEAR;
+ ram_type = SUN4I_NDMA_DRQ_TYPE_SDRAM;
+ }
+
+ if (dir == DMA_MEM_TO_DEV)
+ endpoints = SUN4I_DMA_CFG_DST_DRQ_TYPE(vchan->endpoint) |
+ SUN4I_DMA_CFG_DST_ADDR_MODE(io_mode) |
+ SUN4I_DMA_CFG_SRC_DRQ_TYPE(ram_type) |
+ SUN4I_DMA_CFG_SRC_ADDR_MODE(linear_mode);
+ else
+ endpoints = SUN4I_DMA_CFG_DST_DRQ_TYPE(ram_type) |
+ SUN4I_DMA_CFG_DST_ADDR_MODE(linear_mode) |
+ SUN4I_DMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
+ SUN4I_DMA_CFG_SRC_ADDR_MODE(io_mode);
+
+ 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;
+ dstaddr = sg_dma_address(sg);
+ }
+
+ /*
+ * 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 :|
+ */
+ para = SUN4I_DDMA_MAGIC_SPI_PARAMETERS;
+
+ /* And make a suitable promise */
+ if (vchan->is_dedicated)
+ promise = generate_ddma_promise(chan, srcaddr, dstaddr,
+ sg_dma_len(sg),
+ sconfig);
+ else
+ promise = generate_ndma_promise(chan, srcaddr, dstaddr,
+ sg_dma_len(sg),
+ sconfig, dir);
+
+ if (!promise)
+ return NULL; /* TODO: should we free everything? */
+
+ 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 dma_chan *chan)
+{
+ struct sun4i_dma_dev *priv = to_sun4i_dma_dev(chan->device);
+ struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+ struct sun4i_dma_pchan *pchan = vchan->pchan;
+ LIST_HEAD(head);
+ unsigned long flags;
+
+ spin_lock_irqsave(&vchan->vc.lock, flags);
+ vchan_get_all_descriptors(&vchan->vc, &head);
+ spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+ /*
+ * Clearing the configuration register will halt the pchan. Interrupts
+ * may still trigger, so don't forget to disable them.
+ */
+ if (pchan) {
+ if (pchan->is_dedicated)
+ writel(0, pchan->base + SUN4I_DDMA_CFG_REG);
+ else
+ writel(0, pchan->base + SUN4I_NDMA_CFG_REG);
+ set_pchan_interrupt(priv, pchan, 0, 0);
+ release_pchan(priv, pchan);
+ }
+
+ spin_lock_irqsave(&vchan->vc.lock, flags);
+ /* Clear these so the vchan is usable again */
+ vchan->processing = NULL;
+ vchan->pchan = NULL;
+ spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+ vchan_dma_desc_free_list(&vchan->vc, &head);
+
+ return 0;
+}
+
+static int sun4i_dma_config(struct dma_chan *chan,
+ struct dma_slave_config *config)
+{
+ struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
+
+ memcpy(&vchan->cfg, config, sizeof(*config));
+
+ return 0;
+}
+
+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 >= SUN4I_DDMA_DRQ_TYPE_LIMIT) ||
+ (!is_dedicated && endpoint >= SUN4I_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;
+ enum dma_status ret;
+ size_t bytes = 0;
+
+ ret = dma_cookie_status(chan, cookie, state);
+ if (!state || (ret == DMA_COMPLETE))
+ return ret;
+
+ spin_lock_irqsave(&vchan->vc.lock, flags);
+ vd = vchan_find_desc(&vchan->vc, cookie);
+ if (!vd)
+ goto exit;
+ contract = to_sun4i_dma_contract(vd);
+
+ list_for_each_entry(promise, &contract->demands, list)
+ bytes += promise->len;
+
+ /*
+ * 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 + SUN4I_DDMA_BYTE_COUNT_REG);
+ else
+ bytes += readl(pchan->base + SUN4I_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;
+ struct sun4i_dma_promise *promise;
+ unsigned long pendirq, irqs, disableirqs;
+ int bit, i, free_room, allow_mitigation = 1;
+
+ pendirq = readl_relaxed(priv->base + SUN4I_DMA_IRQ_PENDING_STATUS_REG);
+
+handle_pending:
+
+ disableirqs = 0;
+ free_room = 0;
+
+ for_each_set_bit(bit, &pendirq, 32) {
+ pchan = &pchans[bit >> 1];
+ vchan = pchan->vchan;
+ if (!vchan) /* a terminated channel may still interrupt */
+ continue;
+ 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_move_tail(&vchan->processing->list,
+ &contract->completed_demands);
+
+ /*
+ * Cyclic DMA transfers are special:
+ * - There's always something we can dispatch
+ * - We need to run the callback
+ * - Latency is very important, as this is used by audio
+ * We therefore just cycle through the list and dispatch
+ * whatever we have here, reusing the pchan. There's
+ * no need to run the thread after this.
+ *
+ * For non-cyclic transfers we need to look around,
+ * so we can program some more work, or notify the
+ * client that their transfers have been completed.
+ */
+ if (contract->is_cyclic) {
+ promise = get_next_cyclic_promise(contract);
+ vchan->processing = promise;
+ configure_pchan(pchan, promise);
+ vchan_cyclic_callback(&contract->vd);
+ } else {
+ vchan->processing = NULL;
+ vchan->pchan = NULL;
+
+ free_room = 1;
+ disableirqs |= BIT(bit);
+ release_pchan(priv, pchan);
+ }
+
+ spin_unlock(&vchan->vc.lock);
+ } else {
+ /* Half done interrupt */
+ if (contract->is_cyclic)
+ vchan_cyclic_callback(&contract->vd);
+ else
+ disableirqs |= BIT(bit);
+ }
+ }
+
+ /* Disable the IRQs for events we handled */
+ spin_lock(&priv->lock);
+ irqs = readl_relaxed(priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
+ writel_relaxed(irqs & ~disableirqs,
+ priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
+ spin_unlock(&priv->lock);
+
+ /* Writing 1 to the pending field will clear the pending interrupt */
+ writel_relaxed(pendirq, priv->base + SUN4I_DMA_IRQ_PENDING_STATUS_REG);
+
+ /*
+ * If a pchan was freed, we may be able to schedule something else,
+ * so have a look around
+ */
+ if (free_room) {
+ for (i = 0; i < SUN4I_DMA_NR_MAX_VCHANS; i++) {
+ vchan = &priv->vchans[i];
+ spin_lock(&vchan->vc.lock);
+ __execute_vchan_pending(priv, vchan);
+ spin_unlock(&vchan->vc.lock);
+ }
+ }
+
+ /*
+ * Handle newer interrupts if some showed up, but only do it once
+ * to avoid a too long a loop
+ */
+ if (allow_mitigation) {
+ pendirq = readl_relaxed(priv->base +
+ SUN4I_DMA_IRQ_PENDING_STATUS_REG);
+ if (pendirq) {
+ allow_mitigation = 0;
+ goto handle_pending;
+ }
+ }
+
+ 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)
+ 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_set_max_seg_size(&pdev->dev, SUN4I_DMA_MAX_SEG_SIZE);
+
+ 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_CYCLIC, priv->slave.cap_mask);
+ dma_cap_set(DMA_SLAVE, priv->slave.cap_mask);
+
+ INIT_LIST_HEAD(&priv->slave.channels);
+ 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_prep_dma_cyclic = sun4i_dma_prep_dma_cyclic;
+ priv->slave.device_config = sun4i_dma_config;
+ priv->slave.device_terminate_all = sun4i_dma_terminate_all;
+ priv->slave.copy_align = 2;
+ priv->slave.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+ BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+ BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ priv->slave.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
+ BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
+ BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+ priv->slave.directions = BIT(DMA_DEV_TO_MEM) |
+ BIT(DMA_MEM_TO_DEV);
+ priv->slave.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+
+ priv->slave.dev = &pdev->dev;
+
+ priv->pchans = devm_kcalloc(&pdev->dev, SUN4I_DMA_NR_MAX_CHANNELS,
+ sizeof(struct sun4i_dma_pchan), GFP_KERNEL);
+ priv->vchans = devm_kcalloc(&pdev->dev, SUN4I_DMA_NR_MAX_VCHANS,
+ sizeof(struct sun4i_dma_vchan), GFP_KERNEL);
+ if (!priv->vchans || !priv->pchans)
+ return -ENOMEM;
+
+ /*
+ * [0..SUN4I_NDMA_NR_MAX_CHANNELS) are normal pchans, and
+ * [SUN4I_NDMA_NR_MAX_CHANNELS..SUN4I_DMA_NR_MAX_CHANNELS) are
+ * dedicated ones
+ */
+ for (i = 0; i < SUN4I_NDMA_NR_MAX_CHANNELS; i++)
+ priv->pchans[i].base = priv->base +
+ SUN4I_NDMA_CHANNEL_REG_BASE(i);
+
+ for (j = 0; i < SUN4I_DMA_NR_MAX_CHANNELS; i++, j++) {
+ priv->pchans[i].base = priv->base +
+ SUN4I_DDMA_CHANNEL_REG_BASE(j);
+ priv->pchans[i].is_dedicated = 1;
+ }
+
+ for (i = 0; i < SUN4I_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;
+ }
+
+ /*
+ * Make sure the IRQs are all disabled and accounted for. The bootloader
+ * likes to leave these dirty
+ */
+ writel(0, priv->base + SUN4I_DMA_IRQ_ENABLE_REG);
+ writel(0xFFFFFFFF, priv->base + SUN4I_DMA_IRQ_PENDING_STATUS_REG);
+
+ ret = devm_request_irq(&pdev->dev, priv->irq, sun4i_dma_interrupt,
+ 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 const struct of_device_id sun4i_dma_match[] = {
+ { .compatible = "allwinner,sun4i-a10-dma" },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, sun4i_dma_match);
+
+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 López <emilio@elopez.com.ar>");
+MODULE_LICENSE("GPL");