[PATCH v9 05/19] dmaengine: st_fdma: Add STMicroelectronics FDMA engine driver support

[Peter Griffin <peter.griffin@linaro.org>]

This patch adds support for the Flexible Direct Memory Access (FDMA) core
driver. The FDMA is a slim core CPU with a dedicated firmware.
It is a general purpose DMA controller capable of supporting 16
independent DMA channels. Data moves maybe from memory to memory
or between memory and paced latency critical real time targets and it
is found on al STi based chipsets.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
---
 drivers/dma/Kconfig   |  15 +-
 drivers/dma/Makefile  |   1 +
 drivers/dma/st_fdma.c | 899 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 914 insertions(+), 1 deletion(-)
 create mode 100644 drivers/dma/st_fdma.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 739f797..7c5d946 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -437,6 +437,19 @@ config STE_DMA40
 	help
 	  Support for ST-Ericsson DMA40 controller
 
+config ST_FDMA
+	tristate "ST FDMA dmaengine support"
+	depends on ARCH_STI
+	select ST_SLIM_REMOTEPROC
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for ST FDMA controller.
+	  It supports 16 independent DMA channels, accepts up to 32 DMA requests
+
+	  Say Y here if you have such a chipset.
+	  If unsure, say N.
+
 config STM32_DMA
 	bool "STMicroelectronics STM32 DMA support"
 	depends on ARCH_STM32
@@ -449,6 +462,7 @@ config STM32_DMA
 	  If you have a board based on such a MCU and wish to use DMA say Y or M
 	  here.
 
+
 config S3C24XX_DMAC
 	bool "Samsung S3C24XX DMA support"
 	depends on ARCH_S3C24XX
@@ -567,7 +581,6 @@ config ZX_DMA
 	help
 	  Support the DMA engine for ZTE ZX296702 platform devices.
 
-
 # driver files
 source "drivers/dma/bestcomm/Kconfig"
 
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index e4dc9ca..a4fa336 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_TI_DMA_CROSSBAR) += ti-dma-crossbar.o
 obj-$(CONFIG_TI_EDMA) += edma.o
 obj-$(CONFIG_XGENE_DMA) += xgene-dma.o
 obj-$(CONFIG_ZX_DMA) += zx296702_dma.o
+obj-$(CONFIG_ST_FDMA) += st_fdma.o
 
 obj-y += qcom/
 obj-y += xilinx/
diff --git a/drivers/dma/st_fdma.c b/drivers/dma/st_fdma.c
new file mode 100644
index 0000000..515e1d4
--- /dev/null
+++ b/drivers/dma/st_fdma.c
@@ -0,0 +1,899 @@
+/*
+ * DMA driver for STMicroelectronics STi FDMA controller
+ *
+ * Copyright (C) 2014 STMicroelectronics
+ *
+ * Author: Ludovic Barre <Ludovic.barre@st.com>
+ *	   Peter Griffin <peter.griffin@linaro.org>
+ *
+ * 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/init.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/remoteproc.h>
+
+#include "st_fdma.h"
+
+static inline struct st_fdma_chan *to_st_fdma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct st_fdma_chan, vchan.chan);
+}
+
+static struct st_fdma_desc *to_st_fdma_desc(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct st_fdma_desc, vdesc);
+}
+
+static int st_fdma_dreq_get(struct st_fdma_chan *fchan)
+{
+	struct st_fdma_dev *fdev = fchan->fdev;
+	u32 req_line_cfg = fchan->cfg.req_line;
+	u32 dreq_line;
+	int try = 0;
+
+	/*
+	 * dreq_mask is shared for n channels of fdma, so all accesses must be
+	 * atomic. if the dreq_mask is changed between ffz and set_bit,
+	 * we retry
+	 */
+	do {
+		if (fdev->dreq_mask == ~0L) {
+			dev_err(fdev->dev, "No req lines available\n");
+			return -EINVAL;
+		}
+
+		if (try || req_line_cfg >= ST_FDMA_NR_DREQS) {
+			dev_err(fdev->dev, "Invalid or used req line\n");
+			return -EINVAL;
+		} else {
+			dreq_line = req_line_cfg;
+		}
+
+		try++;
+	} while (test_and_set_bit(dreq_line, &fdev->dreq_mask));
+
+	dev_dbg(fdev->dev, "get dreq_line:%d mask:%#lx\n",
+		dreq_line, fdev->dreq_mask);
+
+	return dreq_line;
+}
+
+static void st_fdma_dreq_put(struct st_fdma_chan *fchan)
+{
+	struct st_fdma_dev *fdev = fchan->fdev;
+
+	dev_dbg(fdev->dev, "put dreq_line:%#x\n", fchan->dreq_line);
+	clear_bit(fchan->dreq_line, &fdev->dreq_mask);
+}
+
+static void st_fdma_xfer_desc(struct st_fdma_chan *fchan)
+{
+	struct virt_dma_desc *vdesc;
+	unsigned long nbytes, ch_cmd, cmd;
+
+	vdesc = vchan_next_desc(&fchan->vchan);
+	if (!vdesc)
+		return;
+
+	fchan->fdesc = to_st_fdma_desc(vdesc);
+	nbytes = fchan->fdesc->node[0].desc->nbytes;
+	cmd = FDMA_CMD_START(fchan->vchan.chan.chan_id);
+	ch_cmd = fchan->fdesc->node[0].pdesc | FDMA_CH_CMD_STA_START;
+
+	/* start the channel for the descriptor */
+	fnode_write(fchan, nbytes, FDMA_CNTN_OFST);
+	fchan_write(fchan, ch_cmd, FDMA_CH_CMD_OFST);
+	writel(cmd,
+		fchan->fdev->slim_rproc->peri + FDMA_CMD_SET_OFST);
+
+	dev_dbg(fchan->fdev->dev, "start chan:%d\n", fchan->vchan.chan.chan_id);
+}
+
+static void st_fdma_ch_sta_update(struct st_fdma_chan *fchan,
+				  unsigned long int_sta)
+{
+	unsigned long ch_sta, ch_err;
+	int ch_id = fchan->vchan.chan.chan_id;
+	struct st_fdma_dev *fdev = fchan->fdev;
+
+	ch_sta = fchan_read(fchan, FDMA_CH_CMD_OFST);
+	ch_err = ch_sta & FDMA_CH_CMD_ERR_MASK;
+	ch_sta &= FDMA_CH_CMD_STA_MASK;
+
+	if (int_sta & FDMA_INT_STA_ERR) {
+		dev_warn(fdev->dev, "chan:%d, error:%ld\n", ch_id, ch_err);
+		fchan->status = DMA_ERROR;
+		return;
+	}
+
+	switch (ch_sta) {
+	case FDMA_CH_CMD_STA_PAUSED:
+		fchan->status = DMA_PAUSED;
+		break;
+
+	case FDMA_CH_CMD_STA_RUNNING:
+		fchan->status = DMA_IN_PROGRESS;
+		break;
+	}
+}
+
+static irqreturn_t st_fdma_irq_handler(int irq, void *dev_id)
+{
+	struct st_fdma_dev *fdev = dev_id;
+	irqreturn_t ret = IRQ_NONE;
+	struct st_fdma_chan *fchan = &fdev->chans[0];
+	unsigned long int_sta, clr;
+
+	int_sta = fdma_read(fdev, FDMA_INT_STA_OFST);
+	clr = int_sta;
+
+	for (; int_sta != 0 ; int_sta >>= 2, fchan++) {
+		if (!(int_sta & (FDMA_INT_STA_CH | FDMA_INT_STA_ERR)))
+			continue;
+
+		spin_lock(&fchan->vchan.lock);
+		st_fdma_ch_sta_update(fchan, int_sta);
+
+		if (fchan->fdesc) {
+			if (!fchan->fdesc->iscyclic) {
+				list_del(&fchan->fdesc->vdesc.node);
+				vchan_cookie_complete(&fchan->fdesc->vdesc);
+				fchan->fdesc = NULL;
+				fchan->status = DMA_COMPLETE;
+			} else {
+				vchan_cyclic_callback(&fchan->fdesc->vdesc);
+			}
+
+			/* Start the next descriptor (if available) */
+			if (!fchan->fdesc)
+				st_fdma_xfer_desc(fchan);
+		}
+
+		spin_unlock(&fchan->vchan.lock);
+		ret = IRQ_HANDLED;
+	}
+
+	fdma_write(fdev, clr, FDMA_INT_CLR_OFST);
+
+	return ret;
+}
+
+static struct dma_chan *st_fdma_of_xlate(struct of_phandle_args *dma_spec,
+					 struct of_dma *ofdma)
+{
+	struct st_fdma_dev *fdev = ofdma->of_dma_data;
+	struct dma_chan *chan;
+	struct st_fdma_chan *fchan;
+	int ret;
+
+	if (dma_spec->args_count < 1)
+		return ERR_PTR(-EINVAL);
+
+	if (fdev->dma_device.dev->of_node != dma_spec->np)
+		return ERR_PTR(-EINVAL);
+
+	ret = rproc_boot(fdev->slim_rproc->rproc);
+	if (ret == -ENOENT)
+		return ERR_PTR(-EPROBE_DEFER);
+	else if (ret)
+		return ERR_PTR(ret);
+
+	chan = dma_get_any_slave_channel(&fdev->dma_device);
+	if (!chan)
+		goto err_chan;
+
+	fchan = to_st_fdma_chan(chan);
+
+	fchan->cfg.of_node = dma_spec->np;
+	fchan->cfg.req_line = dma_spec->args[0];
+	fchan->cfg.req_ctrl = 0;
+	fchan->cfg.type = ST_FDMA_TYPE_FREE_RUN;
+
+	if (dma_spec->args_count > 1)
+		fchan->cfg.req_ctrl = dma_spec->args[1]
+			& FDMA_REQ_CTRL_CFG_MASK;
+
+	if (dma_spec->args_count > 2)
+		fchan->cfg.type = dma_spec->args[2];
+
+	if (fchan->cfg.type == ST_FDMA_TYPE_FREE_RUN) {
+		fchan->dreq_line = 0;
+	} else {
+		fchan->dreq_line = st_fdma_dreq_get(fchan);
+		if (IS_ERR_VALUE(fchan->dreq_line)) {
+			chan = ERR_PTR(fchan->dreq_line);
+			goto err_chan;
+		}
+	}
+
+	dev_dbg(fdev->dev, "xlate req_line:%d type:%d req_ctrl:%#lx\n",
+		fchan->cfg.req_line, fchan->cfg.type, fchan->cfg.req_ctrl);
+
+	return chan;
+
+err_chan:
+	rproc_shutdown(fdev->slim_rproc->rproc);
+	return chan;
+
+}
+
+static void st_fdma_free_desc(struct virt_dma_desc *vdesc)
+{
+	struct st_fdma_desc *fdesc;
+	int i;
+
+	fdesc = to_st_fdma_desc(vdesc);
+	for (i = 0; i < fdesc->n_nodes; i++)
+		dma_pool_free(fdesc->fchan->node_pool, fdesc->node[i].desc,
+			      fdesc->node[i].pdesc);
+	kfree(fdesc);
+}
+
+static struct st_fdma_desc *st_fdma_alloc_desc(struct st_fdma_chan *fchan,
+					       int sg_len)
+{
+	struct st_fdma_desc *fdesc;
+	int i;
+
+	fdesc = kzalloc(sizeof(*fdesc) +
+			sizeof(struct st_fdma_sw_node) * sg_len, GFP_NOWAIT);
+	if (!fdesc)
+		return NULL;
+
+	fdesc->fchan = fchan;
+	fdesc->n_nodes = sg_len;
+	for (i = 0; i < sg_len; i++) {
+		fdesc->node[i].desc = dma_pool_alloc(fchan->node_pool,
+				GFP_NOWAIT, &fdesc->node[i].pdesc);
+		if (!fdesc->node[i].desc)
+			goto err;
+	}
+	return fdesc;
+
+err:
+	while (--i >= 0)
+		dma_pool_free(fchan->node_pool, fdesc->node[i].desc,
+			      fdesc->node[i].pdesc);
+	kfree(fdesc);
+	return NULL;
+}
+
+static int st_fdma_alloc_chan_res(struct dma_chan *chan)
+{
+	struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
+
+	/* Create the dma pool for descriptor allocation */
+	fchan->node_pool = dma_pool_create(dev_name(&chan->dev->device),
+					    fchan->fdev->dev,
+					    sizeof(struct st_fdma_hw_node),
+					    __alignof__(struct st_fdma_hw_node),
+					    0);
+
+	if (!fchan->node_pool) {
+		dev_err(fchan->fdev->dev, "unable to allocate desc pool\n");
+		return -ENOMEM;
+	}
+
+	dev_dbg(fchan->fdev->dev, "alloc ch_id:%d type:%d\n",
+		fchan->vchan.chan.chan_id, fchan->cfg.type);
+
+	return 0;
+}
+
+static void st_fdma_free_chan_res(struct dma_chan *chan)
+{
+	struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
+	struct rproc *rproc = fchan->fdev->slim_rproc->rproc;
+	unsigned long flags;
+
+	LIST_HEAD(head);
+
+	dev_dbg(fchan->fdev->dev, "%s: freeing chan:%d\n",
+		__func__, fchan->vchan.chan.chan_id);
+
+	if (fchan->cfg.type != ST_FDMA_TYPE_FREE_RUN)
+		st_fdma_dreq_put(fchan);
+
+	spin_lock_irqsave(&fchan->vchan.lock, flags);
+	fchan->fdesc = NULL;
+	spin_unlock_irqrestore(&fchan->vchan.lock, flags);
+
+	dma_pool_destroy(fchan->node_pool);
+	fchan->node_pool = NULL;
+	memset(&fchan->cfg, 0, sizeof(struct st_fdma_cfg));
+
+	rproc_shutdown(rproc);
+}
+
+static struct dma_async_tx_descriptor *st_fdma_prep_dma_memcpy(
+	struct dma_chan *chan,	dma_addr_t dst, dma_addr_t src,
+	size_t len, unsigned long flags)
+{
+	struct st_fdma_chan *fchan;
+	struct st_fdma_desc *fdesc;
+	struct st_fdma_hw_node *hw_node;
+
+	if (!len)
+		return NULL;
+
+	fchan = to_st_fdma_chan(chan);
+
+	/* We only require a single descriptor */
+	fdesc = st_fdma_alloc_desc(fchan, 1);
+	if (!fdesc) {
+		dev_err(fchan->fdev->dev, "no memory for desc\n");
+		return NULL;
+	}
+
+	hw_node = fdesc->node[0].desc;
+	hw_node->next = 0;
+	hw_node->control = FDMA_NODE_CTRL_REQ_MAP_FREE_RUN;
+	hw_node->control |= FDMA_NODE_CTRL_SRC_INCR;
+	hw_node->control |= FDMA_NODE_CTRL_DST_INCR;
+	hw_node->control |= FDMA_NODE_CTRL_INT_EON;
+	hw_node->nbytes = len;
+	hw_node->saddr = src;
+	hw_node->daddr = dst;
+	hw_node->generic.length = len;
+	hw_node->generic.sstride = 0;
+	hw_node->generic.dstride = 0;
+
+	return vchan_tx_prep(&fchan->vchan, &fdesc->vdesc, flags);
+}
+
+static int config_reqctrl(struct st_fdma_chan *fchan,
+			  enum dma_transfer_direction direction)
+{
+	u32 maxburst = 0, addr = 0;
+	enum dma_slave_buswidth width;
+	int ch_id = fchan->vchan.chan.chan_id;
+	struct st_fdma_dev *fdev = fchan->fdev;
+
+	switch (direction) {
+
+	case DMA_DEV_TO_MEM:
+		fchan->cfg.req_ctrl &= ~FDMA_REQ_CTRL_WNR;
+		maxburst = fchan->scfg.src_maxburst;
+		width = fchan->scfg.src_addr_width;
+		addr = fchan->scfg.src_addr;
+		break;
+
+	case DMA_MEM_TO_DEV:
+		fchan->cfg.req_ctrl |= FDMA_REQ_CTRL_WNR;
+		maxburst = fchan->scfg.dst_maxburst;
+		width = fchan->scfg.dst_addr_width;
+		addr = fchan->scfg.dst_addr;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	fchan->cfg.req_ctrl &= ~FDMA_REQ_CTRL_OPCODE_MASK;
+
+	switch (width) {
+
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		fchan->cfg.req_ctrl |= FDMA_REQ_CTRL_OPCODE_LD_ST1;
+		break;
+
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		fchan->cfg.req_ctrl |= FDMA_REQ_CTRL_OPCODE_LD_ST2;
+		break;
+
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		fchan->cfg.req_ctrl |= FDMA_REQ_CTRL_OPCODE_LD_ST4;
+		break;
+
+	case DMA_SLAVE_BUSWIDTH_8_BYTES:
+		fchan->cfg.req_ctrl |= FDMA_REQ_CTRL_OPCODE_LD_ST8;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	fchan->cfg.req_ctrl &= ~FDMA_REQ_CTRL_NUM_OPS_MASK;
+	fchan->cfg.req_ctrl |= FDMA_REQ_CTRL_NUM_OPS(maxburst-1);
+	dreq_write(fchan, fchan->cfg.req_ctrl, FDMA_REQ_CTRL_OFST);
+
+	fchan->cfg.dev_addr = addr;
+	fchan->cfg.dir = direction;
+
+	dev_dbg(fdev->dev, "chan:%d config_reqctrl:%#x req_ctrl:%#lx\n",
+		ch_id, addr, fchan->cfg.req_ctrl);
+
+	return 0;
+}
+
+static void fill_hw_node(struct st_fdma_hw_node *hw_node,
+			struct st_fdma_chan *fchan,
+			enum dma_transfer_direction direction)
+{
+	if (direction == DMA_MEM_TO_DEV) {
+		hw_node->control |= FDMA_NODE_CTRL_SRC_INCR;
+		hw_node->control |= FDMA_NODE_CTRL_DST_STATIC;
+		hw_node->daddr = fchan->cfg.dev_addr;
+	} else {
+		hw_node->control |= FDMA_NODE_CTRL_SRC_STATIC;
+		hw_node->control |= FDMA_NODE_CTRL_DST_INCR;
+		hw_node->saddr = fchan->cfg.dev_addr;
+	}
+
+	hw_node->generic.sstride = 0;
+	hw_node->generic.dstride = 0;
+}
+
+static inline struct st_fdma_chan *st_fdma_prep_common(struct dma_chan *chan,
+		size_t len, enum dma_transfer_direction direction)
+{
+	struct st_fdma_chan *fchan;
+
+	if (!chan || !len)
+		return NULL;
+
+	fchan = to_st_fdma_chan(chan);
+
+	if (!is_slave_direction(direction)) {
+		dev_err(fchan->fdev->dev, "bad direction?\n");
+		return NULL;
+	}
+
+	return fchan;
+}
+
+static struct dma_async_tx_descriptor *st_fdma_prep_dma_cyclic(
+		struct dma_chan *chan, dma_addr_t buf_addr, size_t len,
+		size_t period_len, enum dma_transfer_direction direction,
+		unsigned long flags)
+{
+	struct st_fdma_chan *fchan;
+	struct st_fdma_desc *fdesc;
+	int sg_len, i;
+
+	fchan = st_fdma_prep_common(chan, len, direction);
+	if (!fchan)
+		return NULL;
+
+	if (!period_len)
+		return NULL;
+
+	if (config_reqctrl(fchan, direction)) {
+		dev_err(fchan->fdev->dev, "bad width or direction\n");
+		return NULL;
+	}
+
+	/* the buffer length must be a multiple of period_len */
+	if (len % period_len != 0) {
+		dev_err(fchan->fdev->dev, "len is not multiple of period\n");
+		return NULL;
+	}
+
+	sg_len = len / period_len;
+	fdesc = st_fdma_alloc_desc(fchan, sg_len);
+	if (!fdesc) {
+		dev_err(fchan->fdev->dev, "no memory for desc\n");
+		return NULL;
+	}
+
+	fdesc->iscyclic = true;
+
+	for (i = 0; i < sg_len; i++) {
+		struct st_fdma_hw_node *hw_node = fdesc->node[i].desc;
+
+		hw_node->next = fdesc->node[(i + 1) % sg_len].pdesc;
+
+		hw_node->control =
+			FDMA_NODE_CTRL_REQ_MAP_DREQ(fchan->dreq_line);
+		hw_node->control |= FDMA_NODE_CTRL_INT_EON;
+
+		fill_hw_node(hw_node, fchan, direction);
+
+		if (direction == DMA_MEM_TO_DEV)
+			hw_node->saddr = buf_addr + (i * period_len);
+		else
+			hw_node->daddr = buf_addr + (i * period_len);
+
+		hw_node->nbytes = period_len;
+		hw_node->generic.length = period_len;
+	}
+
+	return vchan_tx_prep(&fchan->vchan, &fdesc->vdesc, flags);
+}
+
+static struct dma_async_tx_descriptor *st_fdma_prep_slave_sg(
+		struct dma_chan *chan, struct scatterlist *sgl,
+		unsigned int sg_len, enum dma_transfer_direction direction,
+		unsigned long flags, void *context)
+{
+	struct st_fdma_chan *fchan;
+	struct st_fdma_desc *fdesc;
+	struct st_fdma_hw_node *hw_node;
+	struct scatterlist *sg;
+	int i;
+
+	fchan = st_fdma_prep_common(chan, sg_len, direction);
+	if (!fchan)
+		return NULL;
+
+	if (!sgl)
+		return NULL;
+
+	fdesc = st_fdma_alloc_desc(fchan, sg_len);
+	if (!fdesc) {
+		dev_err(fchan->fdev->dev, "no memory for desc\n");
+		return NULL;
+	}
+
+	fdesc->iscyclic = false;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		hw_node = fdesc->node[i].desc;
+
+		hw_node->next = fdesc->node[(i + 1) % sg_len].pdesc;
+		hw_node->control = FDMA_NODE_CTRL_REQ_MAP_DREQ(fchan->dreq_line);
+
+		fill_hw_node(hw_node, fchan, direction);
+
+		if (direction == DMA_MEM_TO_DEV)
+			hw_node->saddr = sg_dma_address(sg);
+		else
+			hw_node->daddr = sg_dma_address(sg);
+
+		hw_node->nbytes = sg_dma_len(sg);
+		hw_node->generic.length = sg_dma_len(sg);
+	}
+
+	/* interrupt at end of last node */
+	hw_node->control |= FDMA_NODE_CTRL_INT_EON;
+
+	return vchan_tx_prep(&fchan->vchan, &fdesc->vdesc, flags);
+}
+
+static size_t st_fdma_desc_residue(struct st_fdma_chan *fchan,
+				   struct virt_dma_desc *vdesc,
+				   bool in_progress)
+{
+	struct st_fdma_desc *fdesc = fchan->fdesc;
+	size_t residue = 0;
+	dma_addr_t cur_addr = 0;
+	int i;
+
+	if (in_progress) {
+		cur_addr = fchan_read(fchan, FDMA_CH_CMD_OFST);
+		cur_addr &= FDMA_CH_CMD_DATA_MASK;
+	}
+
+	for (i = fchan->fdesc->n_nodes - 1 ; i >= 0; i--) {
+		if (cur_addr == fdesc->node[i].pdesc) {
+			residue += fnode_read(fchan, FDMA_CNTN_OFST);
+			break;
+		}
+		residue += fdesc->node[i].desc->nbytes;
+	}
+
+	return residue;
+}
+
+static enum dma_status st_fdma_tx_status(struct dma_chan *chan,
+					 dma_cookie_t cookie,
+					 struct dma_tx_state *txstate)
+{
+	struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
+	struct virt_dma_desc *vd;
+	enum dma_status ret;
+	unsigned long flags;
+
+	ret = dma_cookie_status(chan, cookie, txstate);
+	if (ret == DMA_COMPLETE || !txstate)
+		return ret;
+
+	spin_lock_irqsave(&fchan->vchan.lock, flags);
+	vd = vchan_find_desc(&fchan->vchan, cookie);
+	if (fchan->fdesc && cookie == fchan->fdesc->vdesc.tx.cookie)
+		txstate->residue = st_fdma_desc_residue(fchan, vd, true);
+	else if (vd)
+		txstate->residue = st_fdma_desc_residue(fchan, vd, false);
+	else
+		txstate->residue = 0;
+
+	spin_unlock_irqrestore(&fchan->vchan.lock, flags);
+
+	return ret;
+}
+
+static void st_fdma_issue_pending(struct dma_chan *chan)
+{
+	struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&fchan->vchan.lock, flags);
+
+	if (vchan_issue_pending(&fchan->vchan) && !fchan->fdesc)
+		st_fdma_xfer_desc(fchan);
+
+	spin_unlock_irqrestore(&fchan->vchan.lock, flags);
+}
+
+static int st_fdma_pause(struct dma_chan *chan)
+{
+	unsigned long flags;
+	LIST_HEAD(head);
+	struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
+	int ch_id = fchan->vchan.chan.chan_id;
+	unsigned long cmd = FDMA_CMD_PAUSE(ch_id);
+
+	dev_dbg(fchan->fdev->dev, "pause chan:%d\n", ch_id);
+
+	spin_lock_irqsave(&fchan->vchan.lock, flags);
+	if (fchan->fdesc)
+		fdma_write(fchan->fdev, cmd, FDMA_CMD_SET_OFST);
+	spin_unlock_irqrestore(&fchan->vchan.lock, flags);
+
+	return 0;
+}
+
+static int st_fdma_resume(struct dma_chan *chan)
+{
+	unsigned long flags;
+	unsigned long val;
+	struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
+	int ch_id = fchan->vchan.chan.chan_id;
+
+	dev_dbg(fchan->fdev->dev, "resume chan:%d\n", ch_id);
+
+	spin_lock_irqsave(&fchan->vchan.lock, flags);
+	if (fchan->fdesc) {
+		val = fchan_read(fchan, FDMA_CH_CMD_OFST);
+		val &= FDMA_CH_CMD_DATA_MASK;
+		fchan_write(fchan, val, FDMA_CH_CMD_OFST);
+	}
+	spin_unlock_irqrestore(&fchan->vchan.lock, flags);
+
+	return 0;
+}
+
+static int st_fdma_terminate_all(struct dma_chan *chan)
+{
+	unsigned long flags;
+	LIST_HEAD(head);
+	struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
+	int ch_id = fchan->vchan.chan.chan_id;
+	unsigned long cmd = FDMA_CMD_PAUSE(ch_id);
+
+	dev_dbg(fchan->fdev->dev, "terminate chan:%d\n", ch_id);
+
+	spin_lock_irqsave(&fchan->vchan.lock, flags);
+	fdma_write(fchan->fdev, cmd, FDMA_CMD_SET_OFST);
+	fchan->fdesc = NULL;
+	vchan_get_all_descriptors(&fchan->vchan, &head);
+	spin_unlock_irqrestore(&fchan->vchan.lock, flags);
+	vchan_dma_desc_free_list(&fchan->vchan, &head);
+
+	return 0;
+}
+
+static int st_fdma_slave_config(struct dma_chan *chan,
+				struct dma_slave_config *slave_cfg)
+{
+	struct st_fdma_chan *fchan = to_st_fdma_chan(chan);
+
+	memcpy(&fchan->scfg, slave_cfg, sizeof(fchan->scfg));
+	return 0;
+}
+
+static const struct st_fdma_driverdata fdma_mpe31_stih407_11 = {
+	.name = "STiH407",
+	.id = 0,
+};
+
+static const struct st_fdma_driverdata fdma_mpe31_stih407_12 = {
+	.name = "STiH407",
+	.id = 1,
+};
+
+static const struct st_fdma_driverdata fdma_mpe31_stih407_13 = {
+	.name = "STiH407",
+	.id = 2,
+};
+
+static const struct of_device_id st_fdma_match[] = {
+	{ .compatible = "st,stih407-fdma-mpe31-11"
+	  , .data = &fdma_mpe31_stih407_11 },
+	{ .compatible = "st,stih407-fdma-mpe31-12"
+	  , .data = &fdma_mpe31_stih407_12 },
+	{ .compatible = "st,stih407-fdma-mpe31-13"
+	  , .data = &fdma_mpe31_stih407_13 },
+	{},
+};
+MODULE_DEVICE_TABLE(of, st_fdma_match);
+
+static int st_fdma_parse_dt(struct platform_device *pdev,
+			const struct st_fdma_driverdata *drvdata,
+			struct st_fdma_dev *fdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	int ret;
+
+	if (!np)
+		goto err;
+
+	ret = of_property_read_u32(np, "dma-channels", &fdev->nr_channels);
+	if (ret)
+		goto err;
+
+	snprintf(fdev->fw_name, FW_NAME_SIZE, "fdma_%s_%d.elf",
+		drvdata->name, drvdata->id);
+
+err:
+	return ret;
+}
+#define FDMA_DMA_BUSWIDTHS	(BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
+				 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
+				 BIT(DMA_SLAVE_BUSWIDTH_3_BYTES) | \
+				 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))
+
+static void st_fdma_free(struct st_fdma_dev *fdev)
+{
+	struct st_fdma_chan *fchan;
+	int i;
+
+	for (i = 0; i < fdev->nr_channels; i++) {
+		fchan = &fdev->chans[i];
+		list_del(&fchan->vchan.chan.device_node);
+		tasklet_kill(&fchan->vchan.task);
+	}
+}
+
+static int st_fdma_probe(struct platform_device *pdev)
+{
+	struct st_fdma_dev *fdev;
+	const struct of_device_id *match;
+	struct device_node *np = pdev->dev.of_node;
+	const struct st_fdma_driverdata *drvdata;
+	int ret, i;
+
+	match = of_match_device((st_fdma_match), &pdev->dev);
+	if (!match || !match->data) {
+		dev_err(&pdev->dev, "No device match found\n");
+		return -ENODEV;
+	}
+
+	drvdata = match->data;
+
+	fdev = devm_kzalloc(&pdev->dev, sizeof(*fdev), GFP_KERNEL);
+	if (!fdev)
+		return -ENOMEM;
+
+	ret = st_fdma_parse_dt(pdev, drvdata, fdev);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to find platform data\n");
+		goto err;
+	}
+
+	fdev->chans = devm_kcalloc(&pdev->dev, fdev->nr_channels,
+				   sizeof(struct st_fdma_chan), GFP_KERNEL);
+	if (!fdev->chans)
+		return -ENOMEM;
+
+	fdev->dev = &pdev->dev;
+	fdev->drvdata = drvdata;
+	platform_set_drvdata(pdev, fdev);
+
+	fdev->irq = platform_get_irq(pdev, 0);
+	if (fdev->irq < 0) {
+		dev_err(&pdev->dev, "Failed to get irq resource\n");
+		return -EINVAL;
+	}
+
+	ret = devm_request_irq(&pdev->dev, fdev->irq, st_fdma_irq_handler, 0,
+			       dev_name(&pdev->dev), fdev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request irq (%d)\n", ret);
+		goto err;
+	}
+
+	fdev->slim_rproc = st_slim_rproc_alloc(pdev, fdev->fw_name);
+	if (!fdev->slim_rproc) {
+		ret = PTR_ERR(fdev->slim_rproc);
+		dev_err(&pdev->dev, "slim_rproc_alloc failed (%d)\n", ret);
+		goto err;
+	}
+
+	/* Initialise list of FDMA channels */
+	INIT_LIST_HEAD(&fdev->dma_device.channels);
+	for (i = 0; i < fdev->nr_channels; i++) {
+		struct st_fdma_chan *fchan = &fdev->chans[i];
+
+		fchan->fdev = fdev;
+		fchan->vchan.desc_free = st_fdma_free_desc;
+		vchan_init(&fchan->vchan, &fdev->dma_device);
+	}
+
+	/* Initialise the FDMA dreq (reserve 0 & 31 for FDMA use) */
+	fdev->dreq_mask = BIT(0) | BIT(31);
+
+	dma_cap_set(DMA_SLAVE, fdev->dma_device.cap_mask);
+	dma_cap_set(DMA_CYCLIC, fdev->dma_device.cap_mask);
+	dma_cap_set(DMA_MEMCPY, fdev->dma_device.cap_mask);
+
+	fdev->dma_device.dev = &pdev->dev;
+	fdev->dma_device.device_alloc_chan_resources = st_fdma_alloc_chan_res;
+	fdev->dma_device.device_free_chan_resources = st_fdma_free_chan_res;
+	fdev->dma_device.device_prep_dma_cyclic	= st_fdma_prep_dma_cyclic;
+	fdev->dma_device.device_prep_slave_sg = st_fdma_prep_slave_sg;
+	fdev->dma_device.device_prep_dma_memcpy = st_fdma_prep_dma_memcpy;
+	fdev->dma_device.device_tx_status = st_fdma_tx_status;
+	fdev->dma_device.device_issue_pending = st_fdma_issue_pending;
+	fdev->dma_device.device_terminate_all = st_fdma_terminate_all;
+	fdev->dma_device.device_config = st_fdma_slave_config;
+	fdev->dma_device.device_pause = st_fdma_pause;
+	fdev->dma_device.device_resume = st_fdma_resume;
+
+	fdev->dma_device.src_addr_widths = FDMA_DMA_BUSWIDTHS;
+	fdev->dma_device.dst_addr_widths = FDMA_DMA_BUSWIDTHS;
+	fdev->dma_device.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+	fdev->dma_device.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+
+	ret = dma_async_device_register(&fdev->dma_device);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"Failed to register DMA device (%d)\n", ret);
+		goto err_rproc;
+	}
+
+	ret = of_dma_controller_register(np, st_fdma_of_xlate, fdev);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"Failed to register controller (%d)\n", ret);
+		goto err_dma_dev;
+	}
+
+	dev_info(&pdev->dev, "ST FDMA engine driver, irq:%d\n", fdev->irq);
+
+	return 0;
+
+err_dma_dev:
+	dma_async_device_unregister(&fdev->dma_device);
+err_rproc:
+	st_fdma_free(fdev);
+	st_slim_rproc_put(fdev->slim_rproc);
+err:
+	return ret;
+}
+
+static int st_fdma_remove(struct platform_device *pdev)
+{
+	struct st_fdma_dev *fdev = platform_get_drvdata(pdev);
+
+	devm_free_irq(&pdev->dev, fdev->irq, fdev);
+	st_slim_rproc_put(fdev->slim_rproc);
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&fdev->dma_device);
+
+	return 0;
+}
+
+static struct platform_driver st_fdma_platform_driver = {
+	.driver = {
+		.name = DRIVER_NAME,
+		.of_match_table = st_fdma_match,
+	},
+	.probe = st_fdma_probe,
+	.remove = st_fdma_remove,
+};
+module_platform_driver(st_fdma_platform_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("STMicroelectronics FDMA engine driver");
+MODULE_AUTHOR("Ludovic.barre <Ludovic.barre@st.com>");
+MODULE_AUTHOR("Peter Griffin <peter.griffin@linaro.org>");
+MODULE_ALIAS("platform: " DRIVER_NAME);
-- 
1.9.1