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openwrt/target/linux/ramips/patches-3.10/0300-DMA-add-rt2880-dma-engine.patch
John Crispin 833943b410 ralink: add dma engine support 
Signed-off-by: John Crispin <blogic@openwrt.org>

SVN-Revision: 39013
2013-12-09 17:28:43 +00:00

671 lines
19 KiB
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From 776726ff626249276936a7e1f865103ea4e1b7e9 Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Tue, 3 Dec 2013 17:05:05 +0100
Subject: [PATCH] DMA: add rt2880 dma engine
Signed-off-by: John Crispin <blogic@openwrt.org>
---
drivers/dma/Kconfig | 6 +
drivers/dma/Makefile | 1 +
drivers/dma/ralink-gdma.c | 596 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 603 insertions(+)
create mode 100644 drivers/dma/ralink-gdma.c
Index: linux-3.10.18/drivers/dma/Kconfig
===================================================================
--- linux-3.10.18.orig/drivers/dma/Kconfig 2013-11-04 13:31:29.000000000 +0100
+++ linux-3.10.18/drivers/dma/Kconfig 2013-12-04 17:52:32.852756567 +0100
@@ -312,6 +312,12 @@
help
Support the MMP PDMA engine for PXA and MMP platfrom.
+config DMA_RALINK
+ tristate "RALINK DMA support"
+ depends on RALINK && SOC_MT7620
+ select DMA_ENGINE
+ select DMA_VIRTUAL_CHANNELS
+
config DMA_ENGINE
bool
Index: linux-3.10.18/drivers/dma/ralink-gdma.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-3.10.18/drivers/dma/ralink-gdma.c 2013-12-05 21:17:22.245128605 +0100
@@ -0,0 +1,577 @@
+/*
+ * Copyright (C) 2013, Lars-Peter Clausen <lars@metafoo.de>
+ * GDMA4740 DMAC support
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/irq.h>
+#include <linux/of_dma.h>
+
+#include "virt-dma.h"
+
+#define GDMA_NR_CHANS 16
+
+#define GDMA_REG_SRC_ADDR(x) (0x00 + (x) * 0x10)
+#define GDMA_REG_DST_ADDR(x) (0x04 + (x) * 0x10)
+
+#define GDMA_REG_CTRL0(x) (0x08 + (x) * 0x10)
+#define GDMA_REG_CTRL0_TX_MASK 0xffff
+#define GDMA_REG_CTRL0_TX_SHIFT 16
+#define GDMA_REG_CTRL0_CURR_MASK 0xff
+#define GDMA_REG_CTRL0_CURR_SHIFT 8
+#define GDMA_REG_CTRL0_SRC_ADDR_FIXED BIT(7)
+#define GDMA_REG_CTRL0_DST_ADDR_FIXED BIT(6)
+#define GDMA_REG_CTRL0_BURST_MASK 0x7
+#define GDMA_REG_CTRL0_BURST_SHIFT 3
+#define GDMA_REG_CTRL0_DONE_INT BIT(2)
+#define GDMA_REG_CTRL0_ENABLE BIT(1)
+#define GDMA_REG_CTRL0_HW_MODE 0
+
+#define GDMA_REG_CTRL1(x) (0x0c + (x) * 0x10)
+#define GDMA_REG_CTRL1_SEG_MASK 0xf
+#define GDMA_REG_CTRL1_SEG_SHIFT 22
+#define GDMA_REG_CTRL1_REQ_MASK 0x3f
+#define GDMA_REG_CTRL1_SRC_REQ_SHIFT 16
+#define GDMA_REG_CTRL1_DST_REQ_SHIFT 8
+#define GDMA_REG_CTRL1_CONTINOUS BIT(14)
+#define GDMA_REG_CTRL1_NEXT_MASK 0x1f
+#define GDMA_REG_CTRL1_NEXT_SHIFT 3
+#define GDMA_REG_CTRL1_COHERENT BIT(2)
+#define GDMA_REG_CTRL1_FAIL BIT(1)
+#define GDMA_REG_CTRL1_MASK BIT(0)
+
+#define GDMA_REG_UNMASK_INT 0x200
+#define GDMA_REG_DONE_INT 0x204
+
+#define GDMA_REG_GCT 0x220
+#define GDMA_REG_GCT_CHAN_MASK 0x3
+#define GDMA_REG_GCT_CHAN_SHIFT 3
+#define GDMA_REG_GCT_VER_MASK 0x3
+#define GDMA_REG_GCT_VER_SHIFT 1
+#define GDMA_REG_GCT_ARBIT_RR BIT(0)
+
+enum gdma_dma_transfer_size {
+ GDMA_TRANSFER_SIZE_4BYTE = 0,
+ GDMA_TRANSFER_SIZE_8BYTE = 1,
+ GDMA_TRANSFER_SIZE_16BYTE = 2,
+ GDMA_TRANSFER_SIZE_32BYTE = 3,
+};
+
+struct gdma_dma_sg {
+ dma_addr_t addr;
+ unsigned int len;
+};
+
+struct gdma_dma_desc {
+ struct virt_dma_desc vdesc;
+
+ enum dma_transfer_direction direction;
+ bool cyclic;
+
+ unsigned int num_sgs;
+ struct gdma_dma_sg sg[];
+};
+
+struct gdma_dmaengine_chan {
+ struct virt_dma_chan vchan;
+ unsigned int id;
+
+ dma_addr_t fifo_addr;
+ unsigned int transfer_shift;
+
+ struct gdma_dma_desc *desc;
+ unsigned int next_sg;
+};
+
+struct gdma_dma_dev {
+ struct dma_device ddev;
+ void __iomem *base;
+ struct clk *clk;
+
+ struct gdma_dmaengine_chan chan[GDMA_NR_CHANS];
+};
+
+static struct gdma_dma_dev *gdma_dma_chan_get_dev(
+ struct gdma_dmaengine_chan *chan)
+{
+ return container_of(chan->vchan.chan.device, struct gdma_dma_dev,
+ ddev);
+}
+
+static struct gdma_dmaengine_chan *to_gdma_dma_chan(struct dma_chan *c)
+{
+ return container_of(c, struct gdma_dmaengine_chan, vchan.chan);
+}
+
+static struct gdma_dma_desc *to_gdma_dma_desc(struct virt_dma_desc *vdesc)
+{
+ return container_of(vdesc, struct gdma_dma_desc, vdesc);
+}
+
+static inline uint32_t gdma_dma_read(struct gdma_dma_dev *dma_dev,
+ unsigned int reg)
+{
+ return readl(dma_dev->base + reg);
+}
+
+static inline void gdma_dma_write(struct gdma_dma_dev *dma_dev,
+ unsigned reg, uint32_t val)
+{
+ //printk("gdma --> %p = 0x%08X\n", dma_dev->base + reg, val);
+ writel(val, dma_dev->base + reg);
+}
+
+static inline void gdma_dma_write_mask(struct gdma_dma_dev *dma_dev,
+ unsigned int reg, uint32_t val, uint32_t mask)
+{
+ uint32_t tmp;
+
+ tmp = gdma_dma_read(dma_dev, reg);
+ tmp &= ~mask;
+ tmp |= val;
+ gdma_dma_write(dma_dev, reg, tmp);
+}
+
+static struct gdma_dma_desc *gdma_dma_alloc_desc(unsigned int num_sgs)
+{
+ return kzalloc(sizeof(struct gdma_dma_desc) +
+ sizeof(struct gdma_dma_sg) * num_sgs, GFP_ATOMIC);
+}
+
+static enum gdma_dma_transfer_size gdma_dma_maxburst(u32 maxburst)
+{
+ if (maxburst <= 7)
+ return GDMA_TRANSFER_SIZE_4BYTE;
+ else if (maxburst <= 15)
+ return GDMA_TRANSFER_SIZE_8BYTE;
+ else if (maxburst <= 31)
+ return GDMA_TRANSFER_SIZE_16BYTE;
+
+ return GDMA_TRANSFER_SIZE_32BYTE;
+}
+
+static int gdma_dma_slave_config(struct dma_chan *c,
+ const struct dma_slave_config *config)
+{
+ struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+ struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
+ enum gdma_dma_transfer_size transfer_size;
+ uint32_t flags;
+ uint32_t ctrl0, ctrl1;
+
+ switch (config->direction) {
+ case DMA_MEM_TO_DEV:
+ ctrl1 = 32 << GDMA_REG_CTRL1_SRC_REQ_SHIFT;
+ ctrl1 |= config->slave_id << GDMA_REG_CTRL1_DST_REQ_SHIFT;
+ flags = GDMA_REG_CTRL0_DST_ADDR_FIXED;
+ transfer_size = gdma_dma_maxburst(config->dst_maxburst);
+ chan->fifo_addr = config->dst_addr;
+ break;
+
+ case DMA_DEV_TO_MEM:
+ ctrl1 = config->slave_id << GDMA_REG_CTRL1_SRC_REQ_SHIFT;
+ ctrl1 |= 32 << GDMA_REG_CTRL1_DST_REQ_SHIFT;
+ flags = GDMA_REG_CTRL0_SRC_ADDR_FIXED;
+ transfer_size = gdma_dma_maxburst(config->src_maxburst);
+ chan->fifo_addr = config->src_addr;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+
+ chan->transfer_shift = 1 + transfer_size;
+
+ ctrl0 = flags | GDMA_REG_CTRL0_HW_MODE;
+ ctrl0 |= GDMA_REG_CTRL0_DONE_INT;
+
+ ctrl1 &= ~(GDMA_REG_CTRL1_NEXT_MASK << GDMA_REG_CTRL1_NEXT_SHIFT);
+ ctrl1 |= chan->id << GDMA_REG_CTRL1_NEXT_SHIFT;
+ ctrl1 |= GDMA_REG_CTRL1_FAIL;
+ ctrl1 &= ~GDMA_REG_CTRL1_CONTINOUS;
+ gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), ctrl0);
+ gdma_dma_write(dma_dev, GDMA_REG_CTRL1(chan->id), ctrl1);
+
+ return 0;
+}
+
+static int gdma_dma_terminate_all(struct dma_chan *c)
+{
+ struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+ struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
+ unsigned long flags;
+ LIST_HEAD(head);
+
+ spin_lock_irqsave(&chan->vchan.lock, flags);
+ gdma_dma_write_mask(dma_dev, GDMA_REG_CTRL0(chan->id), 0,
+ GDMA_REG_CTRL0_ENABLE);
+ chan->desc = NULL;
+ vchan_get_all_descriptors(&chan->vchan, &head);
+ spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+ vchan_dma_desc_free_list(&chan->vchan, &head);
+
+ return 0;
+}
+
+static int gdma_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+ unsigned long arg)
+{
+ struct dma_slave_config *config = (struct dma_slave_config *)arg;
+
+ switch (cmd) {
+ case DMA_SLAVE_CONFIG:
+ return gdma_dma_slave_config(chan, config);
+ case DMA_TERMINATE_ALL:
+ return gdma_dma_terminate_all(chan);
+ default:
+ return -ENOSYS;
+ }
+}
+
+static int gdma_dma_start_transfer(struct gdma_dmaengine_chan *chan)
+{
+ struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
+ dma_addr_t src_addr, dst_addr;
+ struct virt_dma_desc *vdesc;
+ struct gdma_dma_sg *sg;
+
+ gdma_dma_write_mask(dma_dev, GDMA_REG_CTRL0(chan->id), 0,
+ GDMA_REG_CTRL0_ENABLE);
+
+ if (!chan->desc) {
+ vdesc = vchan_next_desc(&chan->vchan);
+ if (!vdesc)
+ return 0;
+ chan->desc = to_gdma_dma_desc(vdesc);
+ chan->next_sg = 0;
+ }
+
+ if (chan->next_sg == chan->desc->num_sgs)
+ chan->next_sg = 0;
+
+ sg = &chan->desc->sg[chan->next_sg];
+
+ if (chan->desc->direction == DMA_MEM_TO_DEV) {
+ src_addr = sg->addr;
+ dst_addr = chan->fifo_addr;
+ } else {
+ src_addr = chan->fifo_addr;
+ dst_addr = sg->addr;
+ }
+ gdma_dma_write(dma_dev, GDMA_REG_SRC_ADDR(chan->id), src_addr);
+ gdma_dma_write(dma_dev, GDMA_REG_DST_ADDR(chan->id), dst_addr);
+ gdma_dma_write_mask(dma_dev, GDMA_REG_CTRL0(chan->id),
+ (sg->len << GDMA_REG_CTRL0_TX_SHIFT) | GDMA_REG_CTRL0_ENABLE,
+ GDMA_REG_CTRL0_TX_MASK << GDMA_REG_CTRL0_TX_SHIFT);
+ chan->next_sg++;
+ gdma_dma_write_mask(dma_dev, GDMA_REG_CTRL1(chan->id), 0, GDMA_REG_CTRL1_MASK);
+
+ return 0;
+}
+
+static void gdma_dma_chan_irq(struct gdma_dmaengine_chan *chan)
+{
+ spin_lock(&chan->vchan.lock);
+ if (chan->desc) {
+ if (chan->desc && chan->desc->cyclic) {
+ vchan_cyclic_callback(&chan->desc->vdesc);
+ } else {
+ if (chan->next_sg == chan->desc->num_sgs) {
+ chan->desc = NULL;
+ vchan_cookie_complete(&chan->desc->vdesc);
+ }
+ }
+ }
+ gdma_dma_start_transfer(chan);
+ spin_unlock(&chan->vchan.lock);
+}
+
+static irqreturn_t gdma_dma_irq(int irq, void *devid)
+{
+ struct gdma_dma_dev *dma_dev = devid;
+ uint32_t unmask, done;
+ unsigned int i;
+
+ unmask = gdma_dma_read(dma_dev, GDMA_REG_UNMASK_INT);
+ gdma_dma_write(dma_dev, GDMA_REG_UNMASK_INT, unmask);
+ done = gdma_dma_read(dma_dev, GDMA_REG_DONE_INT);
+
+ for (i = 0; i < GDMA_NR_CHANS; ++i)
+ if (done & BIT(i))
+ gdma_dma_chan_irq(&dma_dev->chan[i]);
+ gdma_dma_write(dma_dev, GDMA_REG_DONE_INT, done);
+
+ return IRQ_HANDLED;
+}
+
+static void gdma_dma_issue_pending(struct dma_chan *c)
+{
+ struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+ unsigned long flags;
+
+ spin_lock_irqsave(&chan->vchan.lock, flags);
+ if (vchan_issue_pending(&chan->vchan) && !chan->desc)
+ gdma_dma_start_transfer(chan);
+ spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static struct dma_async_tx_descriptor *gdma_dma_prep_slave_sg(
+ struct dma_chan *c, struct scatterlist *sgl,
+ unsigned int sg_len, enum dma_transfer_direction direction,
+ unsigned long flags, void *context)
+{
+ struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+ struct gdma_dma_desc *desc;
+ struct scatterlist *sg;
+ unsigned int i;
+
+ desc = gdma_dma_alloc_desc(sg_len);
+ if (!desc)
+ return NULL;
+
+ for_each_sg(sgl, sg, sg_len, i) {
+ desc->sg[i].addr = sg_dma_address(sg);
+ desc->sg[i].len = sg_dma_len(sg);
+ }
+
+ desc->num_sgs = sg_len;
+ desc->direction = direction;
+ desc->cyclic = false;
+
+ return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static struct dma_async_tx_descriptor *gdma_dma_prep_dma_cyclic(
+ struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
+ size_t period_len, enum dma_transfer_direction direction,
+ unsigned long flags, void *context)
+{
+ struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+ struct gdma_dma_desc *desc;
+ unsigned int num_periods, i;
+
+ if (buf_len % period_len)
+ return NULL;
+
+ num_periods = buf_len / period_len;
+
+ desc = gdma_dma_alloc_desc(num_periods);
+ if (!desc)
+ return NULL;
+
+ for (i = 0; i < num_periods; i++) {
+ desc->sg[i].addr = buf_addr;
+ desc->sg[i].len = period_len;
+ buf_addr += period_len;
+ }
+
+ desc->num_sgs = num_periods;
+ desc->direction = direction;
+ desc->cyclic = true;
+
+ return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static size_t gdma_dma_desc_residue(struct gdma_dmaengine_chan *chan,
+ struct gdma_dma_desc *desc, unsigned int next_sg)
+{
+ struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
+ unsigned int residue, count;
+ unsigned int i;
+
+ residue = 0;
+
+ for (i = next_sg; i < desc->num_sgs; i++)
+ residue += desc->sg[i].len;
+
+ if (next_sg != 0) {
+ count = gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id));
+ count >>= GDMA_REG_CTRL0_CURR_SHIFT;
+ count &= GDMA_REG_CTRL0_CURR_MASK;
+ residue += count << chan->transfer_shift;
+ }
+
+ return residue;
+}
+
+static enum dma_status gdma_dma_tx_status(struct dma_chan *c,
+ dma_cookie_t cookie, struct dma_tx_state *state)
+{
+ struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+ struct virt_dma_desc *vdesc;
+ enum dma_status status;
+ unsigned long flags;
+
+ status = dma_cookie_status(c, cookie, state);
+ if (status == DMA_SUCCESS || !state)
+ return status;
+
+ spin_lock_irqsave(&chan->vchan.lock, flags);
+ vdesc = vchan_find_desc(&chan->vchan, cookie);
+ if (cookie == chan->desc->vdesc.tx.cookie) {
+ state->residue = gdma_dma_desc_residue(chan, chan->desc,
+ chan->next_sg);
+ } else if (vdesc) {
+ state->residue = gdma_dma_desc_residue(chan,
+ to_gdma_dma_desc(vdesc), 0);
+ } else {
+ state->residue = 0;
+ }
+ spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+ return status;
+}
+
+static int gdma_dma_alloc_chan_resources(struct dma_chan *c)
+{
+ return 0;
+}
+
+static void gdma_dma_free_chan_resources(struct dma_chan *c)
+{
+ vchan_free_chan_resources(to_virt_chan(c));
+}
+
+static void gdma_dma_desc_free(struct virt_dma_desc *vdesc)
+{
+ kfree(container_of(vdesc, struct gdma_dma_desc, vdesc));
+}
+
+static struct dma_chan *
+of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+ struct of_dma *ofdma)
+{
+ struct gdma_dma_dev *dma_dev = ofdma->of_dma_data;
+ unsigned int request = dma_spec->args[0];
+
+ if (request >= GDMA_NR_CHANS)
+ return NULL;
+
+ return dma_get_slave_channel(&(dma_dev->chan[request].vchan.chan));
+}
+
+static int gdma_dma_probe(struct platform_device *pdev)
+{
+ struct gdma_dmaengine_chan *chan;
+ struct gdma_dma_dev *dma_dev;
+ struct dma_device *dd;
+ unsigned int i;
+ struct resource *res;
+ uint32_t gct;
+ int ret;
+ int irq;
+
+
+ dma_dev = devm_kzalloc(&pdev->dev, sizeof(*dma_dev), GFP_KERNEL);
+ if (!dma_dev)
+ return -EINVAL;
+
+ dd = &dma_dev->ddev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ dma_dev->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(dma_dev->base))
+ return PTR_ERR(dma_dev->base);
+
+ dma_cap_set(DMA_SLAVE, dd->cap_mask);
+ dma_cap_set(DMA_CYCLIC, dd->cap_mask);
+ dd->device_alloc_chan_resources = gdma_dma_alloc_chan_resources;
+ dd->device_free_chan_resources = gdma_dma_free_chan_resources;
+ dd->device_tx_status = gdma_dma_tx_status;
+ dd->device_issue_pending = gdma_dma_issue_pending;
+ dd->device_prep_slave_sg = gdma_dma_prep_slave_sg;
+ dd->device_prep_dma_cyclic = gdma_dma_prep_dma_cyclic;
+ dd->device_control = gdma_dma_control;
+ dd->dev = &pdev->dev;
+ dd->chancnt = GDMA_NR_CHANS;
+ INIT_LIST_HEAD(&dd->channels);
+
+ for (i = 0; i < dd->chancnt; i++) {
+ chan = &dma_dev->chan[i];
+ chan->id = i;
+ chan->vchan.desc_free = gdma_dma_desc_free;
+ vchan_init(&chan->vchan, dd);
+ }
+
+ ret = dma_async_device_register(dd);
+ if (ret)
+ return ret;
+
+ ret = of_dma_controller_register(pdev->dev.of_node,
+ of_dma_xlate_by_chan_id, dma_dev);
+ if (ret)
+ goto err_unregister;
+
+ irq = platform_get_irq(pdev, 0);
+ ret = request_irq(irq, gdma_dma_irq, 0, dev_name(&pdev->dev), dma_dev);
+ if (ret)
+ goto err_unregister;
+
+ gdma_dma_write(dma_dev, GDMA_REG_UNMASK_INT, 0);
+ gdma_dma_write(dma_dev, GDMA_REG_DONE_INT, BIT(dd->chancnt) - 1);
+
+ gct = gdma_dma_read(dma_dev, GDMA_REG_GCT);
+ dev_info(&pdev->dev, "revision: %d, channels: %d\n",
+ (gct >> GDMA_REG_GCT_VER_SHIFT) & GDMA_REG_GCT_VER_MASK,
+ 8 << ((gct >> GDMA_REG_GCT_CHAN_SHIFT) & GDMA_REG_GCT_CHAN_MASK));
+ platform_set_drvdata(pdev, dma_dev);
+
+ gdma_dma_write(dma_dev, GDMA_REG_GCT, GDMA_REG_GCT_ARBIT_RR);
+
+ return 0;
+
+err_unregister:
+ dma_async_device_unregister(dd);
+ return ret;
+}
+
+static int gdma_dma_remove(struct platform_device *pdev)
+{
+ struct gdma_dma_dev *dma_dev = platform_get_drvdata(pdev);
+ int irq = platform_get_irq(pdev, 0);
+
+ free_irq(irq, dma_dev);
+ of_dma_controller_free(pdev->dev.of_node);
+ dma_async_device_unregister(&dma_dev->ddev);
+
+ return 0;
+}
+
+static const struct of_device_id gdma_of_match_table[] = {
+ { .compatible = "ralink,rt2880-gdma" },
+ { },
+};
+
+static struct platform_driver gdma_dma_driver = {
+ .probe = gdma_dma_probe,
+ .remove = gdma_dma_remove,
+ .driver = {
+ .name = "gdma-rt2880",
+ .owner = THIS_MODULE,
+ .of_match_table = gdma_of_match_table,
+ },
+};
+module_platform_driver(gdma_dma_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("GDMA4740 DMA driver");
+MODULE_LICENSE("GPLv2");
Index: linux-3.10.18/drivers/dma/dmaengine.c
===================================================================
--- linux-3.10.18.orig/drivers/dma/dmaengine.c 2013-11-04 13:31:29.000000000 +0100
+++ linux-3.10.18/drivers/dma/dmaengine.c 2013-12-04 17:52:32.856756568 +0100
@@ -504,6 +504,32 @@
}
/**
+ * dma_request_slave_channel - try to get specific channel exclusively
+ * @chan: target channel
+ */
+struct dma_chan *dma_get_slave_channel(struct dma_chan *chan)
+{
+ int err = -EBUSY;
+
+ /* lock against __dma_request_channel */
+ mutex_lock(&dma_list_mutex);
+
+ if (chan->client_count == 0) {
+ err = dma_chan_get(chan);
+ if (err)
+ pr_debug("%s: failed to get %s: (%d)\n",
+ __func__, dma_chan_name(chan), err);
+ } else
+ chan = NULL;
+
+ mutex_unlock(&dma_list_mutex);
+
+ return chan;
+}
+EXPORT_SYMBOL_GPL(dma_get_slave_channel);
+
+
+/**
* dma_request_channel - try to allocate an exclusive channel
* @mask: capabilities that the channel must satisfy
* @fn: optional callback to disposition available channels
Index: linux-3.10.18/include/linux/dmaengine.h
===================================================================
--- linux-3.10.18.orig/include/linux/dmaengine.h 2013-11-04 13:31:29.000000000 +0100
+++ linux-3.10.18/include/linux/dmaengine.h 2013-12-04 17:52:32.856756568 +0100
@@ -999,6 +999,7 @@
int dma_async_device_register(struct dma_device *device);
void dma_async_device_unregister(struct dma_device *device);
void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
+struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
struct dma_chan *dma_find_channel(enum dma_transaction_type tx_type);
struct dma_chan *net_dma_find_channel(void);
#define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)
Index: linux-3.10.18/drivers/dma/Makefile
===================================================================
--- linux-3.10.18.orig/drivers/dma/Makefile 2013-11-04 13:31:29.000000000 +0100
+++ linux-3.10.18/drivers/dma/Makefile 2013-12-04 17:52:32.856756568 +0100
@@ -38,3 +38,4 @@
obj-$(CONFIG_MMP_TDMA) += mmp_tdma.o
obj-$(CONFIG_DMA_OMAP) += omap-dma.o
obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o
+obj-$(CONFIG_DMA_RALINK) += ralink-gdma.o
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