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From f1c4d9e622c800e1f38b3818f933ec7597d1ccfb Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Sun, 27 Jul 2014 09:29:51 +0100
Subject: [PATCH 47/53] DMA: ralink: 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 |  577 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/dmaengine.h |    1 +
 4 files changed, 585 insertions(+)
 create mode 100644 drivers/dma/ralink-gdma.c

--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -40,6 +40,18 @@ config ASYNC_TX_ENABLE_CHANNEL_SWITCH
 config ARCH_HAS_ASYNC_TX_FIND_CHANNEL
        bool
 
+config DMA_RALINK
+       tristate "RALINK DMA support"
+       depends on RALINK && !SOC_RT288X
+       select DMA_ENGINE
+       select DMA_VIRTUAL_CHANNELS
+
+config MTK_HSDMA
+       tristate "MTK HSDMA support"
+       depends on RALINK && SOC_MT7621
+       select DMA_ENGINE
+       select DMA_VIRTUAL_CHANNELS
+
 config DMA_ENGINE
        bool
 
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -71,6 +71,8 @@ obj-$(CONFIG_TI_EDMA) += edma.o
 obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
 obj-$(CONFIG_ZX_DMA) += zx_dma.o
 obj-$(CONFIG_ST_FDMA) += st_fdma.o
+obj-$(CONFIG_DMA_RALINK) += ralink-gdma.o
+obj-$(CONFIG_MTK_HSDMA) += mtk-hsdma.o
 
 obj-y += qcom/
 obj-y += xilinx/
--- /dev/null
+++ b/drivers/dma/ralink-gdma.c
@@ -0,0 +1,928 @@
+/*
+ *  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.
+ *
+ */
+
+#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 <linux/reset.h>
+#include <linux/of_device.h>
+
+#include "virt-dma.h"
+
+#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_SW_MODE          BIT(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)
+
+#define GDMA_REG_REQSTS                        0x2a0
+#define GDMA_REG_ACKSTS                        0x2a4
+#define GDMA_REG_FINSTS                        0x2a8
+
+/* for RT305X gdma registers */
+#define GDMA_RT305X_CTRL0_REQ_MASK     0xf
+#define GDMA_RT305X_CTRL0_SRC_REQ_SHIFT        12
+#define GDMA_RT305X_CTRL0_DST_REQ_SHIFT        8
+
+#define GDMA_RT305X_CTRL1_FAIL         BIT(4)
+#define GDMA_RT305X_CTRL1_NEXT_MASK    0x7
+#define GDMA_RT305X_CTRL1_NEXT_SHIFT   1
+
+#define GDMA_RT305X_STATUS_INT         0x80
+#define GDMA_RT305X_STATUS_SIGNAL      0x84
+#define GDMA_RT305X_GCT                        0x88
+
+/* for MT7621 gdma registers */
+#define GDMA_REG_PERF_START(x)         (0x230 + (x) * 0x8)
+#define GDMA_REG_PERF_END(x)           (0x234 + (x) * 0x8)
+
+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,
+       GDMA_TRANSFER_SIZE_64BYTE       = 4,
+};
+
+struct gdma_dma_sg {
+       dma_addr_t src_addr;
+       dma_addr_t dst_addr;
+       u32 len;
+};
+
+struct gdma_dma_desc {
+       struct virt_dma_desc vdesc;
+
+       enum dma_transfer_direction direction;
+       bool cyclic;
+
+       u32 residue;
+       unsigned int num_sgs;
+       struct gdma_dma_sg sg[];
+};
+
+struct gdma_dmaengine_chan {
+       struct virt_dma_chan vchan;
+       unsigned int id;
+       unsigned int slave_id;
+
+       dma_addr_t fifo_addr;
+       enum gdma_dma_transfer_size burst_size;
+
+       struct gdma_dma_desc *desc;
+       unsigned int next_sg;
+};
+
+struct gdma_dma_dev {
+       struct dma_device ddev;
+       struct device_dma_parameters dma_parms;
+       struct gdma_data *data;
+       void __iomem *base;
+       struct tasklet_struct task;
+       volatile unsigned long chan_issued;
+       atomic_t cnt;
+
+       struct gdma_dmaengine_chan chan[];
+};
+
+struct gdma_data
+{
+       int chancnt;
+       u32 done_int_reg;
+       void (*init)(struct gdma_dma_dev *dma_dev);
+       int (*start_transfer)(struct gdma_dmaengine_chan *chan);
+};
+
+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)
+{
+       writel(val, dma_dev->base + reg);
+}
+
+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 < 2)
+               return GDMA_TRANSFER_SIZE_4BYTE;
+       else if (maxburst < 4)
+               return GDMA_TRANSFER_SIZE_8BYTE;
+       else if (maxburst < 8)
+               return GDMA_TRANSFER_SIZE_16BYTE;
+       else if (maxburst < 16)
+               return GDMA_TRANSFER_SIZE_32BYTE;
+       else
+               return GDMA_TRANSFER_SIZE_64BYTE;
+}
+
+static int gdma_dma_config(struct dma_chan *c,
+               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);
+
+       if (config->device_fc) {
+               dev_err(dma_dev->ddev.dev, "not support flow controller\n");
+               return -EINVAL;
+       }
+
+       switch (config->direction) {
+       case DMA_MEM_TO_DEV:
+               if (config->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) {
+                       dev_err(dma_dev->ddev.dev, "only support 4 byte buswidth\n");
+                       return -EINVAL;
+               }
+               chan->slave_id = config->slave_id;
+               chan->fifo_addr = config->dst_addr;
+               chan->burst_size = gdma_dma_maxburst(config->dst_maxburst);
+               break;
+       case DMA_DEV_TO_MEM:
+               if (config->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) {
+                       dev_err(dma_dev->ddev.dev, "only support 4 byte buswidth\n");
+                       return -EINVAL;
+               }
+               chan->slave_id = config->slave_id;
+               chan->fifo_addr = config->src_addr;
+               chan->burst_size = gdma_dma_maxburst(config->src_maxburst);
+               break;
+       default:
+               dev_err(dma_dev->ddev.dev, "direction type %d error\n",
+                               config->direction);
+               return -EINVAL;
+       }
+
+       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, timeout;
+       LIST_HEAD(head);
+       int i = 0;
+
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       chan->desc = NULL;
+       clear_bit(chan->id, &dma_dev->chan_issued);
+       vchan_get_all_descriptors(&chan->vchan, &head);
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+       vchan_dma_desc_free_list(&chan->vchan, &head);
+
+       /* wait dma transfer complete */
+       timeout = jiffies + msecs_to_jiffies(5000);
+       while (gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id)) &
+                       GDMA_REG_CTRL0_ENABLE) {
+               if (time_after_eq(jiffies, timeout)) {
+                       dev_err(dma_dev->ddev.dev, "chan %d wait timeout\n",
+                                       chan->id);
+                       /* restore to init value */
+                       gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), 0);
+                       break;
+               }
+               cpu_relax();
+               i++;
+       }
+
+       if (i)
+               dev_dbg(dma_dev->ddev.dev, "terminate chan %d loops %d\n",
+                               chan->id, i);
+
+       return 0;
+}
+
+static void rt305x_dump_reg(struct gdma_dma_dev *dma_dev, int id)
+{
+       dev_dbg(dma_dev->ddev.dev, "chan %d, src %08x, dst %08x, ctr0 %08x, " \
+                       "ctr1 %08x, intr %08x, signal %08x\n", id,
+                       gdma_dma_read(dma_dev, GDMA_REG_SRC_ADDR(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_DST_ADDR(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_CTRL0(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_CTRL1(id)),
+                       gdma_dma_read(dma_dev, GDMA_RT305X_STATUS_INT),
+                       gdma_dma_read(dma_dev, GDMA_RT305X_STATUS_SIGNAL));
+}
+
+static int rt305x_gdma_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 gdma_dma_sg *sg;
+       uint32_t ctrl0, ctrl1;
+
+       /* verify chan is already stopped */
+       ctrl0 = gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id));
+       if (unlikely(ctrl0 & GDMA_REG_CTRL0_ENABLE)) {
+               dev_err(dma_dev->ddev.dev, "chan %d is start(%08x).\n",
+                               chan->id, ctrl0);
+               rt305x_dump_reg(dma_dev, chan->id);
+               return -EINVAL;
+       }
+
+       sg = &chan->desc->sg[chan->next_sg];
+       if (chan->desc->direction == DMA_MEM_TO_DEV) {
+               src_addr = sg->src_addr;
+               dst_addr = chan->fifo_addr;
+               ctrl0 = GDMA_REG_CTRL0_DST_ADDR_FIXED | \
+                       (8 << GDMA_RT305X_CTRL0_SRC_REQ_SHIFT) | \
+                       (chan->slave_id << GDMA_RT305X_CTRL0_DST_REQ_SHIFT);
+       } else if (chan->desc->direction == DMA_DEV_TO_MEM) {
+               src_addr = chan->fifo_addr;
+               dst_addr = sg->dst_addr;
+               ctrl0 = GDMA_REG_CTRL0_SRC_ADDR_FIXED | \
+                       (chan->slave_id << GDMA_RT305X_CTRL0_SRC_REQ_SHIFT) | \
+                       (8 << GDMA_RT305X_CTRL0_DST_REQ_SHIFT);
+       } else if (chan->desc->direction == DMA_MEM_TO_MEM) {
+               /*
+                * TODO: memcpy function have bugs. sometime it will copy
+                * more 8 bytes data when using dmatest verify.
+                */
+               src_addr = sg->src_addr;
+               dst_addr = sg->dst_addr;
+               ctrl0 = GDMA_REG_CTRL0_SW_MODE | \
+                       (8 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
+                       (8 << GDMA_REG_CTRL1_DST_REQ_SHIFT);
+       } else {
+               dev_err(dma_dev->ddev.dev, "direction type %d error\n",
+                               chan->desc->direction);
+               return -EINVAL;
+       }
+
+       ctrl0 |= (sg->len << GDMA_REG_CTRL0_TX_SHIFT) | \
+                (chan->burst_size << GDMA_REG_CTRL0_BURST_SHIFT) | \
+                GDMA_REG_CTRL0_DONE_INT | GDMA_REG_CTRL0_ENABLE;
+       ctrl1 = chan->id << GDMA_REG_CTRL1_NEXT_SHIFT;
+
+       chan->next_sg++;
+       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(dma_dev, GDMA_REG_CTRL1(chan->id), ctrl1);
+
+       /* make sure next_sg is update */
+       wmb();
+       gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), ctrl0);
+
+       return 0;
+}
+
+static void rt3883_dump_reg(struct gdma_dma_dev *dma_dev, int id)
+{
+       dev_dbg(dma_dev->ddev.dev, "chan %d, src %08x, dst %08x, ctr0 %08x, " \
+                       "ctr1 %08x, unmask %08x, done %08x, " \
+                       "req %08x, ack %08x, fin %08x\n", id,
+                       gdma_dma_read(dma_dev, GDMA_REG_SRC_ADDR(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_DST_ADDR(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_CTRL0(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_CTRL1(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_UNMASK_INT),
+                       gdma_dma_read(dma_dev, GDMA_REG_DONE_INT),
+                       gdma_dma_read(dma_dev, GDMA_REG_REQSTS),
+                       gdma_dma_read(dma_dev, GDMA_REG_ACKSTS),
+                       gdma_dma_read(dma_dev, GDMA_REG_FINSTS));
+}
+
+static int rt3883_gdma_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 gdma_dma_sg *sg;
+       uint32_t ctrl0, ctrl1;
+
+       /* verify chan is already stopped */
+       ctrl0 = gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id));
+       if (unlikely(ctrl0 & GDMA_REG_CTRL0_ENABLE)) {
+               dev_err(dma_dev->ddev.dev, "chan %d is start(%08x).\n",
+                               chan->id, ctrl0);
+               rt3883_dump_reg(dma_dev, chan->id);
+               return -EINVAL;
+       }
+
+       sg = &chan->desc->sg[chan->next_sg];
+       if (chan->desc->direction == DMA_MEM_TO_DEV) {
+               src_addr = sg->src_addr;
+               dst_addr = chan->fifo_addr;
+               ctrl0 = GDMA_REG_CTRL0_DST_ADDR_FIXED;
+               ctrl1 = (32 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
+                       (chan->slave_id << GDMA_REG_CTRL1_DST_REQ_SHIFT);
+       } else if (chan->desc->direction == DMA_DEV_TO_MEM) {
+               src_addr = chan->fifo_addr;
+               dst_addr = sg->dst_addr;
+               ctrl0 = GDMA_REG_CTRL0_SRC_ADDR_FIXED;
+               ctrl1 = (chan->slave_id << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
+                       (32 << GDMA_REG_CTRL1_DST_REQ_SHIFT) | \
+                       GDMA_REG_CTRL1_COHERENT;
+       } else if (chan->desc->direction == DMA_MEM_TO_MEM) {
+               src_addr = sg->src_addr;
+               dst_addr = sg->dst_addr;
+               ctrl0 = GDMA_REG_CTRL0_SW_MODE;
+               ctrl1 = (32 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
+                       (32 << GDMA_REG_CTRL1_DST_REQ_SHIFT) | \
+                       GDMA_REG_CTRL1_COHERENT;
+       } else {
+               dev_err(dma_dev->ddev.dev, "direction type %d error\n",
+                               chan->desc->direction);
+               return -EINVAL;
+       }
+
+       ctrl0 |= (sg->len << GDMA_REG_CTRL0_TX_SHIFT) | \
+                (chan->burst_size << GDMA_REG_CTRL0_BURST_SHIFT) | \
+                GDMA_REG_CTRL0_DONE_INT | GDMA_REG_CTRL0_ENABLE;
+       ctrl1 |= chan->id << GDMA_REG_CTRL1_NEXT_SHIFT;
+
+       chan->next_sg++;
+       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(dma_dev, GDMA_REG_CTRL1(chan->id), ctrl1);
+
+       /* make sure next_sg is update */
+       wmb();
+       gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), ctrl0);
+
+       return 0;
+}
+
+static inline int gdma_start_transfer(struct gdma_dma_dev *dma_dev,
+               struct gdma_dmaengine_chan *chan)
+{
+       return dma_dev->data->start_transfer(chan);
+}
+
+static int gdma_next_desc(struct gdma_dmaengine_chan *chan)
+{
+       struct virt_dma_desc *vdesc;
+
+       vdesc = vchan_next_desc(&chan->vchan);
+       if (!vdesc) {
+               chan->desc = NULL;
+               return 0;
+       }
+       chan->desc = to_gdma_dma_desc(vdesc);
+       chan->next_sg = 0;
+
+       return 1;
+}
+
+static void gdma_dma_chan_irq(struct gdma_dma_dev *dma_dev,
+               struct gdma_dmaengine_chan *chan)
+{
+       struct gdma_dma_desc *desc;
+       unsigned long flags;
+       int chan_issued;
+
+       chan_issued = 0;
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       desc = chan->desc;
+       if (desc) {
+               if (desc->cyclic) {
+                       vchan_cyclic_callback(&desc->vdesc);
+                       if (chan->next_sg == desc->num_sgs)
+                               chan->next_sg = 0;
+                       chan_issued = 1;
+               } else {
+                       desc->residue -= desc->sg[chan->next_sg - 1].len;
+                       if (chan->next_sg == desc->num_sgs) {
+                               list_del(&desc->vdesc.node);
+                               vchan_cookie_complete(&desc->vdesc);
+                               chan_issued = gdma_next_desc(chan);
+                       } else
+                               chan_issued = 1;
+               }
+       } else
+               dev_dbg(dma_dev->ddev.dev, "chan %d no desc to complete\n",
+                               chan->id);
+       if (chan_issued)
+               set_bit(chan->id, &dma_dev->chan_issued);
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static irqreturn_t gdma_dma_irq(int irq, void *devid)
+{
+       struct gdma_dma_dev *dma_dev = devid;
+       u32 done, done_reg;
+       unsigned int i;
+
+       done_reg = dma_dev->data->done_int_reg;
+       done = gdma_dma_read(dma_dev, done_reg);
+       if (unlikely(!done))
+               return IRQ_NONE;
+
+       /* clean done bits */
+       gdma_dma_write(dma_dev, done_reg, done);
+
+       i = 0;
+       while (done) {
+               if (done & 0x1) {
+                       gdma_dma_chan_irq(dma_dev, &dma_dev->chan[i]);
+                       atomic_dec(&dma_dev->cnt);
+               }
+               done >>= 1;
+               i++;
+       }
+
+       /* start only have work to do */
+       if (dma_dev->chan_issued)
+               tasklet_schedule(&dma_dev->task);
+
+       return IRQ_HANDLED;
+}
+
+static void gdma_dma_issue_pending(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;
+
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       if (vchan_issue_pending(&chan->vchan) && !chan->desc) {
+               if (gdma_next_desc(chan)) {
+                       set_bit(chan->id, &dma_dev->chan_issued);
+                       tasklet_schedule(&dma_dev->task);
+               } else
+                       dev_dbg(dma_dev->ddev.dev, "chan %d no desc to issue\n",
+                                       chan->id);
+       }
+       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) {
+               dev_err(c->device->dev, "alloc sg decs error\n");
+               return NULL;
+       }
+       desc->residue = 0;
+
+       for_each_sg(sgl, sg, sg_len, i) {
+               if (direction == DMA_MEM_TO_DEV)
+                       desc->sg[i].src_addr = sg_dma_address(sg);
+               else if (direction == DMA_DEV_TO_MEM)
+                       desc->sg[i].dst_addr = sg_dma_address(sg);
+               else {
+                       dev_err(c->device->dev, "direction type %d error\n",
+                                       direction);
+                       goto free_desc;
+               }
+
+               if (unlikely(sg_dma_len(sg) > GDMA_REG_CTRL0_TX_MASK)) {
+                       dev_err(c->device->dev, "sg len too large %d\n",
+                                       sg_dma_len(sg));
+                       goto free_desc;
+               }
+               desc->sg[i].len = sg_dma_len(sg);
+               desc->residue += sg_dma_len(sg);
+       }
+
+       desc->num_sgs = sg_len;
+       desc->direction = direction;
+       desc->cyclic = false;
+
+       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+
+free_desc:
+       kfree(desc);
+       return NULL;
+}
+
+static struct dma_async_tx_descriptor * gdma_dma_prep_dma_memcpy(
+               struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
+               size_t len, unsigned long flags)
+{
+       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+       struct gdma_dma_desc *desc;
+       unsigned int num_periods, i;
+       size_t xfer_count;
+
+       if (len <= 0)
+               return NULL;
+
+       chan->burst_size = gdma_dma_maxburst(len >> 2);
+
+       xfer_count = GDMA_REG_CTRL0_TX_MASK;
+       num_periods = DIV_ROUND_UP(len, xfer_count);
+
+       desc = gdma_dma_alloc_desc(num_periods);
+       if (!desc) {
+               dev_err(c->device->dev, "alloc memcpy decs error\n");
+               return NULL;
+       }
+       desc->residue = len;
+
+       for (i = 0; i < num_periods; i++) {
+               desc->sg[i].src_addr = src;
+               desc->sg[i].dst_addr = dest;
+               if (len > xfer_count) {
+                       desc->sg[i].len = xfer_count;
+               } else {
+                       desc->sg[i].len = len;
+               }
+               src += desc->sg[i].len;
+               dest += desc->sg[i].len;
+               len -= desc->sg[i].len;
+       }
+
+       desc->num_sgs = num_periods;
+       desc->direction = DMA_MEM_TO_MEM;
+       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)
+{
+       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;
+
+       if (period_len > GDMA_REG_CTRL0_TX_MASK) {
+               dev_err(c->device->dev, "cyclic len too large %d\n",
+                               period_len);
+               return NULL;
+       }
+
+       num_periods = buf_len / period_len;
+       desc = gdma_dma_alloc_desc(num_periods);
+       if (!desc) {
+               dev_err(c->device->dev, "alloc cyclic decs error\n");
+               return NULL;
+       }
+       desc->residue = buf_len;
+
+       for (i = 0; i < num_periods; i++) {
+               if (direction == DMA_MEM_TO_DEV)
+                       desc->sg[i].src_addr = buf_addr;
+               else if (direction == DMA_DEV_TO_MEM)
+                       desc->sg[i].dst_addr = buf_addr;
+               else {
+                       dev_err(c->device->dev, "direction type %d error\n",
+                                       direction);
+                       goto free_desc;
+               }
+               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);
+
+free_desc:
+       kfree(desc);
+       return NULL;
+}
+
+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;
+       struct gdma_dma_desc *desc;
+
+       status = dma_cookie_status(c, cookie, state);
+       if (status == DMA_COMPLETE || !state)
+               return status;
+
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       desc = chan->desc;
+       if (desc && (cookie == desc->vdesc.tx.cookie)) {
+               /*
+                * We never update edesc->residue in the cyclic case, so we
+                * can tell the remaining room to the end of the circular
+                * buffer.
+                */
+               if (desc->cyclic)
+                       state->residue = desc->residue -
+                               ((chan->next_sg - 1) * desc->sg[0].len);
+               else
+                       state->residue = desc->residue;
+       } else if ((vdesc = vchan_find_desc(&chan->vchan, cookie)))
+               state->residue = to_gdma_dma_desc(vdesc)->residue;
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+       dev_dbg(c->device->dev, "tx residue %d bytes\n", state->residue);
+
+       return status;
+}
+
+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 void gdma_dma_tasklet(unsigned long arg)
+{
+       struct gdma_dma_dev *dma_dev = (struct gdma_dma_dev *)arg;
+       struct gdma_dmaengine_chan *chan;
+       static unsigned int last_chan;
+       unsigned int i, chan_mask;
+
+       /* record last chan to round robin all chans */
+       i = last_chan;
+       chan_mask = dma_dev->data->chancnt - 1;
+       do {
+               /*
+                * on mt7621. when verify with dmatest with all
+                * channel is enable. we need to limit only two
+                * channel is working at the same time. otherwise the
+                * data will have problem.
+                */
+               if (atomic_read(&dma_dev->cnt) >= 2) {
+                       last_chan = i;
+                       break;
+               }
+
+               if (test_and_clear_bit(i, &dma_dev->chan_issued)) {
+                       chan = &dma_dev->chan[i];
+                       if (chan->desc) {
+                               atomic_inc(&dma_dev->cnt);
+                               gdma_start_transfer(dma_dev, chan);
+                       } else
+                               dev_dbg(dma_dev->ddev.dev, "chan %d no desc to issue\n", chan->id);
+
+                       if (!dma_dev->chan_issued)
+                               break;
+               }
+
+               i = (i + 1) & chan_mask;
+       } while (i != last_chan);
+}
+
+static void rt305x_gdma_init(struct gdma_dma_dev *dma_dev)
+{
+       uint32_t gct;
+
+       /* all chans round robin */
+       gdma_dma_write(dma_dev, GDMA_RT305X_GCT, GDMA_REG_GCT_ARBIT_RR);
+
+       gct = gdma_dma_read(dma_dev, GDMA_RT305X_GCT);
+       dev_info(dma_dev->ddev.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));
+}
+
+static void rt3883_gdma_init(struct gdma_dma_dev *dma_dev)
+{
+       uint32_t gct;
+
+       /* all chans round robin */
+       gdma_dma_write(dma_dev, GDMA_REG_GCT, GDMA_REG_GCT_ARBIT_RR);
+
+       gct = gdma_dma_read(dma_dev, GDMA_REG_GCT);
+       dev_info(dma_dev->ddev.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));
+}
+
+static struct gdma_data rt305x_gdma_data = {
+       .chancnt = 8,
+       .done_int_reg = GDMA_RT305X_STATUS_INT,
+       .init = rt305x_gdma_init,
+       .start_transfer = rt305x_gdma_start_transfer,
+};
+
+static struct gdma_data rt3883_gdma_data = {
+       .chancnt = 16,
+       .done_int_reg = GDMA_REG_DONE_INT,
+       .init = rt3883_gdma_init,
+       .start_transfer = rt3883_gdma_start_transfer,
+};
+
+static const struct of_device_id gdma_of_match_table[] = {
+       { .compatible = "ralink,rt305x-gdma", .data = &rt305x_gdma_data },
+       { .compatible = "ralink,rt3883-gdma", .data = &rt3883_gdma_data },
+       { },
+};
+
+static int gdma_dma_probe(struct platform_device *pdev)
+{
+       const struct of_device_id *match;
+       struct gdma_dmaengine_chan *chan;
+       struct gdma_dma_dev *dma_dev;
+       struct dma_device *dd;
+       unsigned int i;
+       struct resource *res;
+       int ret;
+       int irq;
+       void __iomem *base;
+       struct gdma_data *data;
+
+       ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+       if (ret)
+               return ret;
+
+       match = of_match_device(gdma_of_match_table, &pdev->dev);
+       if (!match)
+               return -EINVAL;
+       data = (struct gdma_data *) match->data;
+
+       dma_dev = devm_kzalloc(&pdev->dev, sizeof(*dma_dev) +
+                       (sizeof(struct gdma_dmaengine_chan) * data->chancnt),
+                       GFP_KERNEL);
+       if (!dma_dev) {
+               dev_err(&pdev->dev, "alloc dma device failed\n");
+               return -EINVAL;
+       }
+       dma_dev->data = data;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(base))
+               return PTR_ERR(base);
+       dma_dev->base = base;
+       tasklet_init(&dma_dev->task, gdma_dma_tasklet, (unsigned long)dma_dev);
+
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0) {
+               dev_err(&pdev->dev, "failed to get irq\n");
+               return -EINVAL;
+       }
+       ret = devm_request_irq(&pdev->dev, irq, gdma_dma_irq,
+                       0, dev_name(&pdev->dev), dma_dev);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to request irq\n");
+               return ret;
+       }
+
+       device_reset(&pdev->dev);
+
+       dd = &dma_dev->ddev;
+       dma_cap_set(DMA_MEMCPY, dd->cap_mask);
+       dma_cap_set(DMA_SLAVE, dd->cap_mask);
+       dma_cap_set(DMA_CYCLIC, dd->cap_mask);
+       dd->device_free_chan_resources = gdma_dma_free_chan_resources;
+       dd->device_prep_dma_memcpy = gdma_dma_prep_dma_memcpy;
+       dd->device_prep_slave_sg = gdma_dma_prep_slave_sg;
+       dd->device_prep_dma_cyclic = gdma_dma_prep_dma_cyclic;
+       dd->device_config = gdma_dma_config;
+       dd->device_terminate_all = gdma_dma_terminate_all;
+       dd->device_tx_status = gdma_dma_tx_status;
+       dd->device_issue_pending = gdma_dma_issue_pending;
+
+       dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+       dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+       dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+       dd->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+
+       dd->dev = &pdev->dev;
+       dd->dev->dma_parms = &dma_dev->dma_parms;
+       dma_set_max_seg_size(dd->dev, GDMA_REG_CTRL0_TX_MASK);
+       INIT_LIST_HEAD(&dd->channels);
+
+       for (i = 0; i < data->chancnt; i++) {
+               chan = &dma_dev->chan[i];
+               chan->id = i;
+               chan->vchan.desc_free = gdma_dma_desc_free;
+               vchan_init(&chan->vchan, dd);
+       }
+
+       /* init hardware */
+       data->init(dma_dev);
+
+       ret = dma_async_device_register(dd);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to register dma device\n");
+               return ret;
+       }
+
+       ret = of_dma_controller_register(pdev->dev.of_node,
+               of_dma_xlate_by_chan_id, dma_dev);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to register of dma controller\n");
+               goto err_unregister;
+       }
+
+       platform_set_drvdata(pdev, dma_dev);
+
+       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);
+
+       tasklet_kill(&dma_dev->task);
+        of_dma_controller_free(pdev->dev.of_node);
+       dma_async_device_unregister(&dma_dev->ddev);
+
+       return 0;
+}
+
+static struct platform_driver gdma_dma_driver = {
+       .probe = gdma_dma_probe,
+       .remove = gdma_dma_remove,
+       .driver = {
+               .name = "gdma-rt2880",
+               .of_match_table = gdma_of_match_table,
+       },
+};
+module_platform_driver(gdma_dma_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Ralink/MTK DMA driver");
+MODULE_LICENSE("GPL v2");
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -525,6 +525,7 @@ static inline void dma_set_unmap(struct
 struct dmaengine_unmap_data *
 dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags);
 void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap);
+struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
 #else
 static inline void dma_set_unmap(struct dma_async_tx_descriptor *tx,
                                 struct dmaengine_unmap_data *unmap)
--- /dev/null
+++ b/drivers/dma/mtk-hsdma.c
@@ -0,0 +1,767 @@
+/*
+ *  Copyright (C) 2015, Michael Lee <igvtee@gmail.com>
+ *  MTK HSDMA 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.
+ *
+ */
+
+#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 <linux/reset.h>
+#include <linux/of_device.h>
+
+#include "virt-dma.h"
+
+#define HSDMA_BASE_OFFSET              0x800
+
+#define HSDMA_REG_TX_BASE              0x00
+#define HSDMA_REG_TX_CNT               0x04
+#define HSDMA_REG_TX_CTX               0x08
+#define HSDMA_REG_TX_DTX               0x0c
+#define HSDMA_REG_RX_BASE              0x100
+#define HSDMA_REG_RX_CNT               0x104
+#define HSDMA_REG_RX_CRX               0x108
+#define HSDMA_REG_RX_DRX               0x10c
+#define HSDMA_REG_INFO                 0x200
+#define HSDMA_REG_GLO_CFG              0x204
+#define HSDMA_REG_RST_CFG              0x208
+#define HSDMA_REG_DELAY_INT            0x20c
+#define HSDMA_REG_FREEQ_THRES          0x210
+#define HSDMA_REG_INT_STATUS           0x220
+#define HSDMA_REG_INT_MASK             0x228
+#define HSDMA_REG_SCH_Q01              0x280
+#define HSDMA_REG_SCH_Q23              0x284
+
+#define HSDMA_DESCS_MAX                        0xfff
+#define HSDMA_DESCS_NUM                        8
+#define HSDMA_DESCS_MASK               (HSDMA_DESCS_NUM - 1)
+#define HSDMA_NEXT_DESC(x)             (((x) + 1) & HSDMA_DESCS_MASK)
+
+/* HSDMA_REG_INFO */
+#define HSDMA_INFO_INDEX_MASK          0xf
+#define HSDMA_INFO_INDEX_SHIFT         24
+#define HSDMA_INFO_BASE_MASK           0xff
+#define HSDMA_INFO_BASE_SHIFT          16
+#define HSDMA_INFO_RX_MASK             0xff
+#define HSDMA_INFO_RX_SHIFT            8
+#define HSDMA_INFO_TX_MASK             0xff
+#define HSDMA_INFO_TX_SHIFT            0
+
+/* HSDMA_REG_GLO_CFG */
+#define HSDMA_GLO_TX_2B_OFFSET         BIT(31)
+#define HSDMA_GLO_CLK_GATE             BIT(30)
+#define HSDMA_GLO_BYTE_SWAP            BIT(29)
+#define HSDMA_GLO_MULTI_DMA            BIT(10)
+#define HSDMA_GLO_TWO_BUF              BIT(9)
+#define HSDMA_GLO_32B_DESC             BIT(8)
+#define HSDMA_GLO_BIG_ENDIAN           BIT(7)
+#define HSDMA_GLO_TX_DONE              BIT(6)
+#define HSDMA_GLO_BT_MASK              0x3
+#define HSDMA_GLO_BT_SHIFT             4
+#define HSDMA_GLO_RX_BUSY              BIT(3)
+#define HSDMA_GLO_RX_DMA               BIT(2)
+#define HSDMA_GLO_TX_BUSY              BIT(1)
+#define HSDMA_GLO_TX_DMA               BIT(0)
+
+#define HSDMA_BT_SIZE_16BYTES          (0 << HSDMA_GLO_BT_SHIFT)
+#define HSDMA_BT_SIZE_32BYTES          (1 << HSDMA_GLO_BT_SHIFT)
+#define HSDMA_BT_SIZE_64BYTES          (2 << HSDMA_GLO_BT_SHIFT)
+#define HSDMA_BT_SIZE_128BYTES         (3 << HSDMA_GLO_BT_SHIFT)
+
+#define HSDMA_GLO_DEFAULT              (HSDMA_GLO_MULTI_DMA | \
+               HSDMA_GLO_RX_DMA | HSDMA_GLO_TX_DMA | HSDMA_BT_SIZE_32BYTES)
+
+/* HSDMA_REG_RST_CFG */
+#define HSDMA_RST_RX_SHIFT             16
+#define HSDMA_RST_TX_SHIFT             0
+
+/* HSDMA_REG_DELAY_INT */
+#define HSDMA_DELAY_INT_EN             BIT(15)
+#define HSDMA_DELAY_PEND_OFFSET                8
+#define HSDMA_DELAY_TIME_OFFSET                0
+#define HSDMA_DELAY_TX_OFFSET          16
+#define HSDMA_DELAY_RX_OFFSET          0
+
+#define HSDMA_DELAY_INIT(x)            (HSDMA_DELAY_INT_EN | \
+               ((x) << HSDMA_DELAY_PEND_OFFSET))
+#define HSDMA_DELAY(x)                 ((HSDMA_DELAY_INIT(x) << \
+               HSDMA_DELAY_TX_OFFSET) | HSDMA_DELAY_INIT(x))
+
+/* HSDMA_REG_INT_STATUS */
+#define HSDMA_INT_DELAY_RX_COH         BIT(31)
+#define HSDMA_INT_DELAY_RX_INT         BIT(30)
+#define HSDMA_INT_DELAY_TX_COH         BIT(29)
+#define HSDMA_INT_DELAY_TX_INT         BIT(28)
+#define HSDMA_INT_RX_MASK              0x3
+#define HSDMA_INT_RX_SHIFT             16
+#define HSDMA_INT_RX_Q0                        BIT(16)
+#define HSDMA_INT_TX_MASK              0xf
+#define HSDMA_INT_TX_SHIFT             0
+#define HSDMA_INT_TX_Q0                        BIT(0)
+
+/* tx/rx dma desc flags */
+#define HSDMA_PLEN_MASK                        0x3fff
+#define HSDMA_DESC_DONE                        BIT(31)
+#define HSDMA_DESC_LS0                 BIT(30)
+#define HSDMA_DESC_PLEN0(_x)           (((_x) & HSDMA_PLEN_MASK) << 16)
+#define HSDMA_DESC_TAG                 BIT(15)
+#define HSDMA_DESC_LS1                 BIT(14)
+#define HSDMA_DESC_PLEN1(_x)           ((_x) & HSDMA_PLEN_MASK)
+
+/* align 4 bytes */
+#define HSDMA_ALIGN_SIZE               3
+/* align size 128bytes */
+#define HSDMA_MAX_PLEN                 0x3f80
+
+struct hsdma_desc {
+       u32 addr0;
+       u32 flags;
+       u32 addr1;
+       u32 unused;
+};
+
+struct mtk_hsdma_sg {
+       dma_addr_t src_addr;
+       dma_addr_t dst_addr;
+       u32 len;
+};
+
+struct mtk_hsdma_desc {
+       struct virt_dma_desc vdesc;
+       unsigned int num_sgs;
+       struct mtk_hsdma_sg sg[1];
+};
+
+struct mtk_hsdma_chan {
+       struct virt_dma_chan vchan;
+       unsigned int id;
+       dma_addr_t desc_addr;
+       int tx_idx;
+       int rx_idx;
+       struct hsdma_desc *tx_ring;
+       struct hsdma_desc *rx_ring;
+       struct mtk_hsdma_desc *desc;
+       unsigned int next_sg;
+};
+
+struct mtk_hsdam_engine {
+       struct dma_device ddev;
+       struct device_dma_parameters dma_parms;
+       void __iomem *base;
+       struct tasklet_struct task;
+       volatile unsigned long chan_issued;
+
+       struct mtk_hsdma_chan chan[1];
+};
+
+static inline struct mtk_hsdam_engine *mtk_hsdma_chan_get_dev(
+               struct mtk_hsdma_chan *chan)
+{
+       return container_of(chan->vchan.chan.device, struct mtk_hsdam_engine,
+                       ddev);
+}
+
+static inline struct mtk_hsdma_chan *to_mtk_hsdma_chan(struct dma_chan *c)
+{
+       return container_of(c, struct mtk_hsdma_chan, vchan.chan);
+}
+
+static inline struct mtk_hsdma_desc *to_mtk_hsdma_desc(
+               struct virt_dma_desc *vdesc)
+{
+       return container_of(vdesc, struct mtk_hsdma_desc, vdesc);
+}
+
+static inline u32 mtk_hsdma_read(struct mtk_hsdam_engine *hsdma, u32 reg)
+{
+       return readl(hsdma->base + reg);
+}
+
+static inline void mtk_hsdma_write(struct mtk_hsdam_engine *hsdma,
+               unsigned reg, u32 val)
+{
+       writel(val, hsdma->base + reg);
+}
+
+static void mtk_hsdma_reset_chan(struct mtk_hsdam_engine *hsdma,
+               struct mtk_hsdma_chan *chan)
+{
+       chan->tx_idx = 0;
+       chan->rx_idx = HSDMA_DESCS_NUM - 1;
+
+       mtk_hsdma_write(hsdma, HSDMA_REG_TX_CTX, chan->tx_idx);
+       mtk_hsdma_write(hsdma, HSDMA_REG_RX_CRX, chan->rx_idx);
+
+       mtk_hsdma_write(hsdma, HSDMA_REG_RST_CFG,
+                       0x1 << (chan->id + HSDMA_RST_TX_SHIFT));
+       mtk_hsdma_write(hsdma, HSDMA_REG_RST_CFG,
+                       0x1 << (chan->id + HSDMA_RST_RX_SHIFT));
+}
+
+static void hsdma_dump_reg(struct mtk_hsdam_engine *hsdma)
+{
+       dev_dbg(hsdma->ddev.dev, "tbase %08x, tcnt %08x, " \
+                       "tctx %08x, tdtx: %08x, rbase %08x, " \
+                       "rcnt %08x, rctx %08x, rdtx %08x\n",
+                       mtk_hsdma_read(hsdma, HSDMA_REG_TX_BASE),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_TX_CNT),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_TX_CTX),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_TX_DTX),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_RX_BASE),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_RX_CNT),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_RX_CRX),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_RX_DRX));
+
+       dev_dbg(hsdma->ddev.dev, "info %08x, glo %08x, delay %08x, " \
+                       "intr_stat %08x, intr_mask %08x\n",
+                       mtk_hsdma_read(hsdma, HSDMA_REG_INFO),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_GLO_CFG),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_DELAY_INT),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_INT_STATUS),
+                       mtk_hsdma_read(hsdma, HSDMA_REG_INT_MASK));
+}
+
+static void hsdma_dump_desc(struct mtk_hsdam_engine *hsdma,
+               struct mtk_hsdma_chan *chan)
+{
+       struct hsdma_desc *tx_desc;
+       struct hsdma_desc *rx_desc;
+       int i;
+
+       dev_dbg(hsdma->ddev.dev, "tx idx: %d, rx idx: %d\n",
+                       chan->tx_idx, chan->rx_idx);
+
+       for (i = 0; i < HSDMA_DESCS_NUM; i++) {
+               tx_desc = &chan->tx_ring[i];
+               rx_desc = &chan->rx_ring[i];
+
+               dev_dbg(hsdma->ddev.dev, "%d tx addr0: %08x, flags %08x, " \
+                               "tx addr1: %08x, rx addr0 %08x, flags %08x\n",
+                               i, tx_desc->addr0, tx_desc->flags, \
+                               tx_desc->addr1, rx_desc->addr0, rx_desc->flags);
+       }
+}
+
+static void mtk_hsdma_reset(struct mtk_hsdam_engine *hsdma,
+               struct mtk_hsdma_chan *chan)
+{
+       int i;
+
+       /* disable dma */
+       mtk_hsdma_write(hsdma, HSDMA_REG_GLO_CFG, 0);
+
+       /* disable intr */
+       mtk_hsdma_write(hsdma, HSDMA_REG_INT_MASK, 0);
+
+       /* init desc value */
+       for (i = 0; i < HSDMA_DESCS_NUM; i++) {
+               chan->tx_ring[i].addr0 = 0;
+               chan->tx_ring[i].flags = HSDMA_DESC_LS0 |
+                       HSDMA_DESC_DONE;
+       }
+       for (i = 0; i < HSDMA_DESCS_NUM; i++) {
+               chan->rx_ring[i].addr0 = 0;
+               chan->rx_ring[i].flags = 0;
+       }
+
+       /* reset */
+       mtk_hsdma_reset_chan(hsdma, chan);
+
+       /* enable intr */
+       mtk_hsdma_write(hsdma, HSDMA_REG_INT_MASK, HSDMA_INT_RX_Q0);
+
+       /* enable dma */
+       mtk_hsdma_write(hsdma, HSDMA_REG_GLO_CFG, HSDMA_GLO_DEFAULT);
+}
+
+static int mtk_hsdma_terminate_all(struct dma_chan *c)
+{
+       struct mtk_hsdma_chan *chan = to_mtk_hsdma_chan(c);
+       struct mtk_hsdam_engine *hsdma = mtk_hsdma_chan_get_dev(chan);
+       unsigned long timeout;
+       LIST_HEAD(head);
+
+       spin_lock_bh(&chan->vchan.lock);
+       chan->desc = NULL;
+       clear_bit(chan->id, &hsdma->chan_issued);
+       vchan_get_all_descriptors(&chan->vchan, &head);
+       spin_unlock_bh(&chan->vchan.lock);
+
+       vchan_dma_desc_free_list(&chan->vchan, &head);
+
+       /* wait dma transfer complete */
+       timeout = jiffies + msecs_to_jiffies(2000);
+       while (mtk_hsdma_read(hsdma, HSDMA_REG_GLO_CFG) &
+                       (HSDMA_GLO_RX_BUSY | HSDMA_GLO_TX_BUSY)) {
+               if (time_after_eq(jiffies, timeout)) {
+                       hsdma_dump_desc(hsdma, chan);
+                       mtk_hsdma_reset(hsdma, chan);
+                       dev_err(hsdma->ddev.dev, "timeout, reset it\n");
+                       break;
+               }
+               cpu_relax();
+       }
+
+       return 0;
+}
+
+static int mtk_hsdma_start_transfer(struct mtk_hsdam_engine *hsdma,
+               struct mtk_hsdma_chan *chan)
+{
+       dma_addr_t src, dst;
+       size_t len, tlen;
+       struct hsdma_desc *tx_desc, *rx_desc;
+       struct mtk_hsdma_sg *sg;
+       unsigned int i;
+       int rx_idx;
+
+       sg = &chan->desc->sg[0];
+       len = sg->len;
+       chan->desc->num_sgs = DIV_ROUND_UP(len, HSDMA_MAX_PLEN);
+
+       /* tx desc */
+       src = sg->src_addr;
+       for (i = 0; i < chan->desc->num_sgs; i++) {
+               if (len > HSDMA_MAX_PLEN)
+                       tlen = HSDMA_MAX_PLEN;
+               else
+                       tlen = len;
+
+               if (i & 0x1) {
+                       tx_desc->addr1 = src;
+                       tx_desc->flags |= HSDMA_DESC_PLEN1(tlen);
+               } else {
+                       tx_desc = &chan->tx_ring[chan->tx_idx];
+                       tx_desc->addr0 = src;
+                       tx_desc->flags = HSDMA_DESC_PLEN0(tlen);
+
+                       /* update index */
+                       chan->tx_idx = HSDMA_NEXT_DESC(chan->tx_idx);
+               }
+
+               src += tlen;
+               len -= tlen;
+       }
+       if (i & 0x1)
+               tx_desc->flags |= HSDMA_DESC_LS0;
+       else
+               tx_desc->flags |= HSDMA_DESC_LS1;
+
+       /* rx desc */
+       rx_idx = HSDMA_NEXT_DESC(chan->rx_idx);
+       len = sg->len;
+       dst = sg->dst_addr;
+       for (i = 0; i < chan->desc->num_sgs; i++) {
+               rx_desc = &chan->rx_ring[rx_idx];
+               if (len > HSDMA_MAX_PLEN)
+                       tlen = HSDMA_MAX_PLEN;
+               else
+                       tlen = len;
+
+               rx_desc->addr0 = dst;
+               rx_desc->flags = HSDMA_DESC_PLEN0(tlen);
+
+               dst += tlen;
+               len -= tlen;
+
+               /* update index */
+               rx_idx = HSDMA_NEXT_DESC(rx_idx);
+       }
+
+       /* make sure desc and index all up to date */
+       wmb();
+       mtk_hsdma_write(hsdma, HSDMA_REG_TX_CTX, chan->tx_idx);
+
+       return 0;
+}
+
+static int gdma_next_desc(struct mtk_hsdma_chan *chan)
+{
+       struct virt_dma_desc *vdesc;
+
+       vdesc = vchan_next_desc(&chan->vchan);
+       if (!vdesc) {
+               chan->desc = NULL;
+               return 0;
+       }
+       chan->desc = to_mtk_hsdma_desc(vdesc);
+       chan->next_sg = 0;
+
+       return 1;
+}
+
+static void mtk_hsdma_chan_done(struct mtk_hsdam_engine *hsdma,
+               struct mtk_hsdma_chan *chan)
+{
+       struct mtk_hsdma_desc *desc;
+       int chan_issued;
+
+       chan_issued = 0;
+       spin_lock_bh(&chan->vchan.lock);
+       desc = chan->desc;
+       if (likely(desc)) {
+               if (chan->next_sg == desc->num_sgs) {
+                       list_del(&desc->vdesc.node);
+                       vchan_cookie_complete(&desc->vdesc);
+                       chan_issued = gdma_next_desc(chan);
+               }
+       } else
+               dev_dbg(hsdma->ddev.dev, "no desc to complete\n");
+
+       if (chan_issued)
+               set_bit(chan->id, &hsdma->chan_issued);
+       spin_unlock_bh(&chan->vchan.lock);
+}
+
+static irqreturn_t mtk_hsdma_irq(int irq, void *devid)
+{
+       struct mtk_hsdam_engine *hsdma = devid;
+       u32 status;
+
+       status = mtk_hsdma_read(hsdma, HSDMA_REG_INT_STATUS);
+       if (unlikely(!status))
+               return IRQ_NONE;
+
+       if (likely(status & HSDMA_INT_RX_Q0))
+               tasklet_schedule(&hsdma->task);
+       else
+               dev_dbg(hsdma->ddev.dev, "unhandle irq status %08x\n",
+                               status);
+       /* clean intr bits */
+       mtk_hsdma_write(hsdma, HSDMA_REG_INT_STATUS, status);
+
+       return IRQ_HANDLED;
+}
+
+static void mtk_hsdma_issue_pending(struct dma_chan *c)
+{
+       struct mtk_hsdma_chan *chan = to_mtk_hsdma_chan(c);
+       struct mtk_hsdam_engine *hsdma = mtk_hsdma_chan_get_dev(chan);
+
+       spin_lock_bh(&chan->vchan.lock);
+       if (vchan_issue_pending(&chan->vchan) && !chan->desc) {
+               if (gdma_next_desc(chan)) {
+                       set_bit(chan->id, &hsdma->chan_issued);
+                       tasklet_schedule(&hsdma->task);
+               } else
+                       dev_dbg(hsdma->ddev.dev, "no desc to issue\n");
+       }
+       spin_unlock_bh(&chan->vchan.lock);
+}
+
+static struct dma_async_tx_descriptor * mtk_hsdma_prep_dma_memcpy(
+               struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
+               size_t len, unsigned long flags)
+{
+       struct mtk_hsdma_chan *chan = to_mtk_hsdma_chan(c);
+       struct mtk_hsdma_desc *desc;
+
+       if (len <= 0)
+               return NULL;
+
+       desc = kzalloc(sizeof(struct mtk_hsdma_desc), GFP_ATOMIC);
+       if (!desc) {
+               dev_err(c->device->dev, "alloc memcpy decs error\n");
+               return NULL;
+       }
+
+       desc->sg[0].src_addr = src;
+       desc->sg[0].dst_addr = dest;
+       desc->sg[0].len = len;
+
+       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static enum dma_status mtk_hsdma_tx_status(struct dma_chan *c,
+               dma_cookie_t cookie, struct dma_tx_state *state)
+{
+       return dma_cookie_status(c, cookie, state);
+}
+
+static void mtk_hsdma_free_chan_resources(struct dma_chan *c)
+{
+       vchan_free_chan_resources(to_virt_chan(c));
+}
+
+static void mtk_hsdma_desc_free(struct virt_dma_desc *vdesc)
+{
+       kfree(container_of(vdesc, struct mtk_hsdma_desc, vdesc));
+}
+
+static void mtk_hsdma_tx(struct mtk_hsdam_engine *hsdma)
+{
+       struct mtk_hsdma_chan *chan;
+
+       if (test_and_clear_bit(0, &hsdma->chan_issued)) {
+               chan = &hsdma->chan[0];
+               if (chan->desc) {
+                       mtk_hsdma_start_transfer(hsdma, chan);
+               } else
+                       dev_dbg(hsdma->ddev.dev,"chan 0 no desc to issue\n");
+       }
+}
+
+static void mtk_hsdma_rx(struct mtk_hsdam_engine *hsdma)
+{
+       struct mtk_hsdma_chan *chan;
+       int next_idx, drx_idx, cnt;
+
+       chan = &hsdma->chan[0];
+       next_idx = HSDMA_NEXT_DESC(chan->rx_idx);
+       drx_idx = mtk_hsdma_read(hsdma, HSDMA_REG_RX_DRX);
+
+       cnt = (drx_idx - next_idx) & HSDMA_DESCS_MASK;
+       if (!cnt)
+               return;
+
+       chan->next_sg += cnt;
+       chan->rx_idx = (chan->rx_idx + cnt) & HSDMA_DESCS_MASK;
+
+       /* update rx crx */
+       wmb();
+       mtk_hsdma_write(hsdma, HSDMA_REG_RX_CRX, chan->rx_idx);
+
+       mtk_hsdma_chan_done(hsdma, chan);
+}
+
+static void mtk_hsdma_tasklet(unsigned long arg)
+{
+       struct mtk_hsdam_engine *hsdma = (struct mtk_hsdam_engine *)arg;
+
+       mtk_hsdma_rx(hsdma);
+       mtk_hsdma_tx(hsdma);
+}
+
+static int mtk_hsdam_alloc_desc(struct mtk_hsdam_engine *hsdma,
+               struct mtk_hsdma_chan *chan)
+{
+       int i;
+
+       chan->tx_ring = dma_alloc_coherent(hsdma->ddev.dev,
+                       2 * HSDMA_DESCS_NUM * sizeof(*chan->tx_ring),
+                       &chan->desc_addr, GFP_ATOMIC | __GFP_ZERO);
+       if (!chan->tx_ring)
+               goto no_mem;
+
+       chan->rx_ring = &chan->tx_ring[HSDMA_DESCS_NUM];
+
+       /* init tx ring value */
+       for (i = 0; i < HSDMA_DESCS_NUM; i++)
+               chan->tx_ring[i].flags = HSDMA_DESC_LS0 | HSDMA_DESC_DONE;
+
+       return 0;
+no_mem:
+       return -ENOMEM;
+}
+
+static void mtk_hsdam_free_desc(struct mtk_hsdam_engine *hsdma,
+               struct mtk_hsdma_chan *chan)
+{
+       if (chan->tx_ring) {
+               dma_free_coherent(hsdma->ddev.dev,
+                               2 * HSDMA_DESCS_NUM * sizeof(*chan->tx_ring),
+                               chan->tx_ring, chan->desc_addr);
+               chan->tx_ring = NULL;
+               chan->rx_ring = NULL;
+       }
+}
+
+static int mtk_hsdma_init(struct mtk_hsdam_engine *hsdma)
+{
+       struct mtk_hsdma_chan *chan;
+       int ret;
+       u32 reg;
+
+       /* init desc */
+       chan = &hsdma->chan[0];
+       ret = mtk_hsdam_alloc_desc(hsdma, chan);
+       if (ret)
+               return ret;
+
+       /* tx */
+       mtk_hsdma_write(hsdma, HSDMA_REG_TX_BASE, chan->desc_addr);
+       mtk_hsdma_write(hsdma, HSDMA_REG_TX_CNT, HSDMA_DESCS_NUM);
+       /* rx */
+       mtk_hsdma_write(hsdma, HSDMA_REG_RX_BASE, chan->desc_addr +
+                       (sizeof(struct hsdma_desc) * HSDMA_DESCS_NUM));
+       mtk_hsdma_write(hsdma, HSDMA_REG_RX_CNT, HSDMA_DESCS_NUM);
+       /* reset */
+       mtk_hsdma_reset_chan(hsdma, chan);
+
+       /* enable rx intr */
+       mtk_hsdma_write(hsdma, HSDMA_REG_INT_MASK, HSDMA_INT_RX_Q0);
+
+       /* enable dma */
+       mtk_hsdma_write(hsdma, HSDMA_REG_GLO_CFG, HSDMA_GLO_DEFAULT);
+
+       /* hardware info */
+       reg = mtk_hsdma_read(hsdma, HSDMA_REG_INFO);
+       dev_info(hsdma->ddev.dev, "rx: %d, tx: %d\n",
+                       (reg >> HSDMA_INFO_RX_SHIFT) & HSDMA_INFO_RX_MASK,
+                       (reg >> HSDMA_INFO_TX_SHIFT) & HSDMA_INFO_TX_MASK);
+
+       hsdma_dump_reg(hsdma);
+
+       return ret;
+}
+
+static void mtk_hsdma_uninit(struct mtk_hsdam_engine *hsdma)
+{
+       struct mtk_hsdma_chan *chan;
+
+       /* disable dma */
+       mtk_hsdma_write(hsdma, HSDMA_REG_GLO_CFG, 0);
+
+       /* disable intr */
+       mtk_hsdma_write(hsdma, HSDMA_REG_INT_MASK, 0);
+
+       /* free desc */
+       chan = &hsdma->chan[0];
+       mtk_hsdam_free_desc(hsdma, chan);
+
+       /* tx */
+       mtk_hsdma_write(hsdma, HSDMA_REG_TX_BASE, 0);
+       mtk_hsdma_write(hsdma, HSDMA_REG_TX_CNT, 0);
+       /* rx */
+       mtk_hsdma_write(hsdma, HSDMA_REG_RX_BASE, 0);
+       mtk_hsdma_write(hsdma, HSDMA_REG_RX_CNT, 0);
+       /* reset */
+       mtk_hsdma_reset_chan(hsdma, chan);
+}
+
+static const struct of_device_id mtk_hsdma_of_match[] = {
+       { .compatible = "mediatek,mt7621-hsdma" },
+       { },
+};
+
+static int mtk_hsdma_probe(struct platform_device *pdev)
+{
+       const struct of_device_id *match;
+       struct mtk_hsdma_chan *chan;
+       struct mtk_hsdam_engine *hsdma;
+       struct dma_device *dd;
+       struct resource *res;
+       int ret;
+       int irq;
+       void __iomem *base;
+
+       ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+       if (ret)
+               return ret;
+
+       match = of_match_device(mtk_hsdma_of_match, &pdev->dev);
+       if (!match)
+               return -EINVAL;
+
+       hsdma = devm_kzalloc(&pdev->dev, sizeof(*hsdma), GFP_KERNEL);
+       if (!hsdma) {
+               dev_err(&pdev->dev, "alloc dma device failed\n");
+               return -EINVAL;
+       }
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(base))
+               return PTR_ERR(base);
+       hsdma->base = base + HSDMA_BASE_OFFSET;
+       tasklet_init(&hsdma->task, mtk_hsdma_tasklet, (unsigned long)hsdma);
+
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0) {
+               dev_err(&pdev->dev, "failed to get irq\n");
+               return -EINVAL;
+       }
+       ret = devm_request_irq(&pdev->dev, irq, mtk_hsdma_irq,
+                       0, dev_name(&pdev->dev), hsdma);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to request irq\n");
+               return ret;
+       }
+
+       device_reset(&pdev->dev);
+
+       dd = &hsdma->ddev;
+       dma_cap_set(DMA_MEMCPY, dd->cap_mask);
+       dd->copy_align = HSDMA_ALIGN_SIZE;
+       dd->device_free_chan_resources = mtk_hsdma_free_chan_resources;
+       dd->device_prep_dma_memcpy = mtk_hsdma_prep_dma_memcpy;
+       dd->device_terminate_all = mtk_hsdma_terminate_all;
+       dd->device_tx_status = mtk_hsdma_tx_status;
+       dd->device_issue_pending = mtk_hsdma_issue_pending;
+       dd->dev = &pdev->dev;
+       dd->dev->dma_parms = &hsdma->dma_parms;
+       dma_set_max_seg_size(dd->dev, HSDMA_MAX_PLEN);
+       INIT_LIST_HEAD(&dd->channels);
+
+       chan = &hsdma->chan[0];
+       chan->id = 0;
+       chan->vchan.desc_free = mtk_hsdma_desc_free;
+       vchan_init(&chan->vchan, dd);
+
+       /* init hardware */
+       ret = mtk_hsdma_init(hsdma);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to alloc ring descs\n");
+               return ret;
+       }
+
+       ret = dma_async_device_register(dd);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to register dma device\n");
+               return ret;
+       }
+
+       ret = of_dma_controller_register(pdev->dev.of_node,
+                       of_dma_xlate_by_chan_id, hsdma);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to register of dma controller\n");
+               goto err_unregister;
+       }
+
+       platform_set_drvdata(pdev, hsdma);
+
+       return 0;
+
+err_unregister:
+       dma_async_device_unregister(dd);
+       return ret;
+}
+
+static int mtk_hsdma_remove(struct platform_device *pdev)
+{
+       struct mtk_hsdam_engine *hsdma = platform_get_drvdata(pdev);
+
+       mtk_hsdma_uninit(hsdma);
+
+       of_dma_controller_free(pdev->dev.of_node);
+       dma_async_device_unregister(&hsdma->ddev);
+
+       return 0;
+}
+
+static struct platform_driver mtk_hsdma_driver = {
+       .probe = mtk_hsdma_probe,
+       .remove = mtk_hsdma_remove,
+       .driver = {
+               .name = "hsdma-mt7621",
+               .of_match_table = mtk_hsdma_of_match,
+       },
+};
+module_platform_driver(mtk_hsdma_driver);
+
+MODULE_AUTHOR("Michael Lee <igvtee@gmail.com>");
+MODULE_DESCRIPTION("MTK HSDMA driver");
+MODULE_LICENSE("GPL v2");

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