[2/2] dmaengine: milbeaut-hdmac: Add HDMAC driver for Milbeaut platforms
diff mbox series

Message ID 20190613005247.2048-1-jassisinghbrar@gmail.com
State New
Headers show
Series
  • Add support for AHB DMA controller on Milbeaut series
Related show

Commit Message

Jassi Brar June 13, 2019, 12:52 a.m. UTC
From: Jassi Brar <jaswinder.singh@linaro.org>

Driver for Socionext Milbeaut HDMAC controller. The controller has
upto 8 floating channels, that need a predefined slave-id to work
from a set of slaves.

Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
---
 drivers/dma/Kconfig          |  10 +
 drivers/dma/Makefile         |   1 +
 drivers/dma/milbeaut-hdmac.c | 572 +++++++++++++++++++++++++++++++++++
 3 files changed, 583 insertions(+)
 create mode 100644 drivers/dma/milbeaut-hdmac.c

Comments

Vinod Koul June 24, 2019, 6:44 a.m. UTC | #1
On 12-06-19, 19:52, jassisinghbrar@gmail.com wrote:

> +#include <linux/bits.h>
> +#include <linux/clk.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmaengine.h>
> +#include <linux/interrupt.h>
> +#include <linux/iopoll.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_dma.h>

Do we need both, IIRC of_dma.h does include of.h!

> +/* mc->vc.lock must be held by caller */
> +static void milbeaut_chan_start(struct milbeaut_hdmac_chan *mc,
> +				struct milbeaut_hdmac_desc *md)
> +{
> +	struct scatterlist *sg;
> +	u32  cb, ca, src_addr, dest_addr, len;
           ^^
double space

> +static irqreturn_t milbeaut_hdmac_interrupt(int irq, void *dev_id)
> +{
> +	struct milbeaut_hdmac_chan *mc = dev_id;
> +	struct milbeaut_hdmac_desc *md;
> +	irqreturn_t ret = IRQ_HANDLED;
> +	u32 val;
> +
> +	spin_lock(&mc->vc.lock);
> +
> +	/* Ack and Disable irqs */
> +	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACB);
> +	val &= ~(FIELD_PREP(MLB_HDMAC_SS, 0x7));
                                         ^^^^
Magic ..?

> +static int milbeaut_hdmac_chan_pause(struct dma_chan *chan)
> +{
> +	struct virt_dma_chan *vc = to_virt_chan(chan);
> +	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
> +	u32 val;
> +
> +	spin_lock(&mc->vc.lock);
> +	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
> +	val |= MLB_HDMAC_PB;
> +	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);

We really should have an updatel() and friends in kernel, feel free to
add in your driver though!

> +static int milbeaut_hdmac_chan_init(struct platform_device *pdev,
> +				    struct milbeaut_hdmac_device *mdev,
> +				    int chan_id)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct milbeaut_hdmac_chan *mc = &mdev->channels[chan_id];
> +	char *irq_name;
> +	int irq, ret;
> +
> +	irq = platform_get_irq(pdev, chan_id);
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "failed to get IRQ number for ch%d\n",
> +			chan_id);
> +		return irq;
> +	}
> +
> +	irq_name = devm_kasprintf(dev, GFP_KERNEL, "milbeaut-hdmac-%d",
> +				  chan_id);
> +	if (!irq_name)
> +		return -ENOMEM;
> +
> +	ret = devm_request_irq(dev, irq, milbeaut_hdmac_interrupt,
> +			       IRQF_SHARED, irq_name, mc);

I tend to dislike using devm_request_irq(), we have no control over when
the irq is freed and what is a spirious irq is running while we are
unrolling, so IMHO it make sense to free up and ensure all tasklets are
quiesced when remove returns

> +	if (ret)
> +		return ret;
> +
> +	mc->mdev = mdev;
> +	mc->reg_ch_base = mdev->reg_base + MLB_HDMAC_CH_STRIDE * (chan_id + 1);
> +	mc->vc.desc_free = milbeaut_hdmac_desc_free;
> +	vchan_init(&mc->vc, &mdev->ddev);

who kills the vc->task?

> +static int milbeaut_hdmac_remove(struct platform_device *pdev)
> +{
> +	struct milbeaut_hdmac_device *mdev = platform_get_drvdata(pdev);
> +	struct dma_chan *chan;
> +	int ret;
> +
> +	/*
> +	 * Before reaching here, almost all descriptors have been freed by the
> +	 * ->device_free_chan_resources() hook. However, each channel might
> +	 * be still holding one descriptor that was on-flight at that moment.
> +	 * Terminate it to make sure this hardware is no longer running. Then,
> +	 * free the channel resources once again to avoid memory leak.
> +	 */
> +	list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
> +		ret = dmaengine_terminate_sync(chan);
> +		if (ret)
> +			return ret;
> +		milbeaut_hdmac_free_chan_resources(chan);
> +	}
> +
> +	of_dma_controller_free(pdev->dev.of_node);
> +	dma_async_device_unregister(&mdev->ddev);
> +	clk_disable_unprepare(mdev->clk);

And as suspected we have active tasklets and irq at this time :(
Jassi Brar Aug. 16, 2019, 2:25 a.m. UTC | #2
On Mon, Jun 24, 2019 at 1:47 AM Vinod Koul <vkoul@kernel.org> wrote:
>
> On 12-06-19, 19:52, jassisinghbrar@gmail.com wrote:
>
> > +#include <linux/bits.h>
> > +#include <linux/clk.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/dmaengine.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/iopoll.h>
> > +#include <linux/list.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_dma.h>
>
> Do we need both, IIRC of_dma.h does include of.h!
>
OK

> > +/* mc->vc.lock must be held by caller */
> > +static void milbeaut_chan_start(struct milbeaut_hdmac_chan *mc,
> > +                             struct milbeaut_hdmac_desc *md)
> > +{
> > +     struct scatterlist *sg;
> > +     u32  cb, ca, src_addr, dest_addr, len;
>            ^^
> double space
>
OK

> > +static irqreturn_t milbeaut_hdmac_interrupt(int irq, void *dev_id)
> > +{
> > +     struct milbeaut_hdmac_chan *mc = dev_id;
> > +     struct milbeaut_hdmac_desc *md;
> > +     irqreturn_t ret = IRQ_HANDLED;
> > +     u32 val;
> > +
> > +     spin_lock(&mc->vc.lock);
> > +
> > +     /* Ack and Disable irqs */
> > +     val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACB);
> > +     val &= ~(FIELD_PREP(MLB_HDMAC_SS, 0x7));
>                                          ^^^^
> Magic ..?
>
OK, will define a macro for 7

> > +static int milbeaut_hdmac_chan_pause(struct dma_chan *chan)
> > +{
> > +     struct virt_dma_chan *vc = to_virt_chan(chan);
> > +     struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
> > +     u32 val;
> > +
> > +     spin_lock(&mc->vc.lock);
> > +     val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
> > +     val |= MLB_HDMAC_PB;
> > +     writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);
>
> We really should have an updatel() and friends in kernel, feel free to
> add in your driver though!
>
I'll pass on that for now.

> > +static int milbeaut_hdmac_chan_init(struct platform_device *pdev,
> > +                                 struct milbeaut_hdmac_device *mdev,
> > +                                 int chan_id)
> > +{
> > +     struct device *dev = &pdev->dev;
> > +     struct milbeaut_hdmac_chan *mc = &mdev->channels[chan_id];
> > +     char *irq_name;
> > +     int irq, ret;
> > +
> > +     irq = platform_get_irq(pdev, chan_id);
> > +     if (irq < 0) {
> > +             dev_err(&pdev->dev, "failed to get IRQ number for ch%d\n",
> > +                     chan_id);
> > +             return irq;
> > +     }
> > +
> > +     irq_name = devm_kasprintf(dev, GFP_KERNEL, "milbeaut-hdmac-%d",
> > +                               chan_id);
> > +     if (!irq_name)
> > +             return -ENOMEM;
> > +
> > +     ret = devm_request_irq(dev, irq, milbeaut_hdmac_interrupt,
> > +                            IRQF_SHARED, irq_name, mc);
>
> I tend to dislike using devm_request_irq(), we have no control over when
> the irq is freed and what is a spirious irq is running while we are
> unrolling, so IMHO it make sense to free up and ensure all tasklets are
> quiesced when remove returns
>
If the code is written clean and tight we need not be so paranoid.

> > +     if (ret)
> > +             return ret;
> > +
> > +     mc->mdev = mdev;
> > +     mc->reg_ch_base = mdev->reg_base + MLB_HDMAC_CH_STRIDE * (chan_id + 1);
> > +     mc->vc.desc_free = milbeaut_hdmac_desc_free;
> > +     vchan_init(&mc->vc, &mdev->ddev);
>
> who kills the vc->task?
>
vchan_synchronize() called from milbeaut_hdmac_synchronize()

> > +static int milbeaut_hdmac_remove(struct platform_device *pdev)
> > +{
> > +     struct milbeaut_hdmac_device *mdev = platform_get_drvdata(pdev);
> > +     struct dma_chan *chan;
> > +     int ret;
> > +
> > +     /*
> > +      * Before reaching here, almost all descriptors have been freed by the
> > +      * ->device_free_chan_resources() hook. However, each channel might
> > +      * be still holding one descriptor that was on-flight at that moment.
> > +      * Terminate it to make sure this hardware is no longer running. Then,
> > +      * free the channel resources once again to avoid memory leak.
> > +      */
> > +     list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
> > +             ret = dmaengine_terminate_sync(chan);
> > +             if (ret)
> > +                     return ret;
> > +             milbeaut_hdmac_free_chan_resources(chan);
> > +     }
> > +
> > +     of_dma_controller_free(pdev->dev.of_node);
> > +     dma_async_device_unregister(&mdev->ddev);
> > +     clk_disable_unprepare(mdev->clk);
>
> And as suspected we have active tasklets and irq at this time :(
>
Not sure how is that....

thanks.
Vinod Koul Aug. 16, 2019, 4:43 a.m. UTC | #3
On 15-08-19, 21:25, Jassi Brar wrote:
> On Mon, Jun 24, 2019 at 1:47 AM Vinod Koul <vkoul@kernel.org> wrote:
> >
> > On 12-06-19, 19:52, jassisinghbrar@gmail.com wrote:
> >
> > > +#include <linux/bits.h>
> > > +#include <linux/clk.h>
> > > +#include <linux/dma-mapping.h>
> > > +#include <linux/dmaengine.h>
> > > +#include <linux/interrupt.h>
> > > +#include <linux/iopoll.h>
> > > +#include <linux/list.h>
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/of_dma.h>
> >
> > Do we need both, IIRC of_dma.h does include of.h!
> >
> OK
> 
> > > +/* mc->vc.lock must be held by caller */
> > > +static void milbeaut_chan_start(struct milbeaut_hdmac_chan *mc,
> > > +                             struct milbeaut_hdmac_desc *md)
> > > +{
> > > +     struct scatterlist *sg;
> > > +     u32  cb, ca, src_addr, dest_addr, len;
> >            ^^
> > double space
> >
> OK
> 
> > > +static irqreturn_t milbeaut_hdmac_interrupt(int irq, void *dev_id)
> > > +{
> > > +     struct milbeaut_hdmac_chan *mc = dev_id;
> > > +     struct milbeaut_hdmac_desc *md;
> > > +     irqreturn_t ret = IRQ_HANDLED;
> > > +     u32 val;
> > > +
> > > +     spin_lock(&mc->vc.lock);
> > > +
> > > +     /* Ack and Disable irqs */
> > > +     val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACB);
> > > +     val &= ~(FIELD_PREP(MLB_HDMAC_SS, 0x7));
> >                                          ^^^^
> > Magic ..?
> >
> OK, will define a macro for 7
> 
> > > +static int milbeaut_hdmac_chan_pause(struct dma_chan *chan)
> > > +{
> > > +     struct virt_dma_chan *vc = to_virt_chan(chan);
> > > +     struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
> > > +     u32 val;
> > > +
> > > +     spin_lock(&mc->vc.lock);
> > > +     val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
> > > +     val |= MLB_HDMAC_PB;
> > > +     writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);
> >
> > We really should have an updatel() and friends in kernel, feel free to
> > add in your driver though!
> >
> I'll pass on that for now.
> 
> > > +static int milbeaut_hdmac_chan_init(struct platform_device *pdev,
> > > +                                 struct milbeaut_hdmac_device *mdev,
> > > +                                 int chan_id)
> > > +{
> > > +     struct device *dev = &pdev->dev;
> > > +     struct milbeaut_hdmac_chan *mc = &mdev->channels[chan_id];
> > > +     char *irq_name;
> > > +     int irq, ret;
> > > +
> > > +     irq = platform_get_irq(pdev, chan_id);
> > > +     if (irq < 0) {
> > > +             dev_err(&pdev->dev, "failed to get IRQ number for ch%d\n",
> > > +                     chan_id);
> > > +             return irq;
> > > +     }
> > > +
> > > +     irq_name = devm_kasprintf(dev, GFP_KERNEL, "milbeaut-hdmac-%d",
> > > +                               chan_id);
> > > +     if (!irq_name)
> > > +             return -ENOMEM;
> > > +
> > > +     ret = devm_request_irq(dev, irq, milbeaut_hdmac_interrupt,
> > > +                            IRQF_SHARED, irq_name, mc);
> >
> > I tend to dislike using devm_request_irq(), we have no control over when
> > the irq is freed and what is a spirious irq is running while we are
> > unrolling, so IMHO it make sense to free up and ensure all tasklets are
> > quiesced when remove returns
> >
> If the code is written clean and tight we need not be so paranoid.
> 
> > > +     if (ret)
> > > +             return ret;
> > > +
> > > +     mc->mdev = mdev;
> > > +     mc->reg_ch_base = mdev->reg_base + MLB_HDMAC_CH_STRIDE * (chan_id + 1);
> > > +     mc->vc.desc_free = milbeaut_hdmac_desc_free;
> > > +     vchan_init(&mc->vc, &mdev->ddev);
> >
> > who kills the vc->task?
> >
> vchan_synchronize() called from milbeaut_hdmac_synchronize()

But that can be skipped by called, from driver pov we need to ensure
that it is killed

> > > +static int milbeaut_hdmac_remove(struct platform_device *pdev)
> > > +{
> > > +     struct milbeaut_hdmac_device *mdev = platform_get_drvdata(pdev);
> > > +     struct dma_chan *chan;
> > > +     int ret;
> > > +
> > > +     /*
> > > +      * Before reaching here, almost all descriptors have been freed by the
> > > +      * ->device_free_chan_resources() hook. However, each channel might
> > > +      * be still holding one descriptor that was on-flight at that moment.
> > > +      * Terminate it to make sure this hardware is no longer running. Then,
> > > +      * free the channel resources once again to avoid memory leak.
> > > +      */
> > > +     list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
> > > +             ret = dmaengine_terminate_sync(chan);
> > > +             if (ret)
> > > +                     return ret;
> > > +             milbeaut_hdmac_free_chan_resources(chan);
> > > +     }
> > > +
> > > +     of_dma_controller_free(pdev->dev.of_node);
> > > +     dma_async_device_unregister(&mdev->ddev);
> > > +     clk_disable_unprepare(mdev->clk);
> >
> > And as suspected we have active tasklets and irq at this time :(
> >
> Not sure how is that....

Since you use devm variants, and driver tasklet is not killed, irq can
be fired (spurious as well) and can run irq and schedule a tasklet. How
do you prevent that?

Thanks

Patch
diff mbox series

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 703275cc29de..15a1d5263ca1 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -347,6 +347,16 @@  config MCF_EDMA
 	  minimal intervention from a host processor.
 	  This module can be found on Freescale ColdFire mcf5441x SoCs.
 
+config MILBEAUT_HDMAC
+	tristate "Milbeaut AHB DMA support"
+	depends on ARCH_MILBEAUT || COMPILE_TEST
+	depends on OF
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Say yes here to support the Socionext Milbeaut
+	  HDMAC device.
+
 config MMP_PDMA
 	bool "MMP PDMA support"
 	depends on ARCH_MMP || ARCH_PXA || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 6126e1c3a875..d0a9f46726e8 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -45,6 +45,7 @@  obj-$(CONFIG_INTEL_IOP_ADMA) += iop-adma.o
 obj-$(CONFIG_INTEL_MIC_X100_DMA) += mic_x100_dma.o
 obj-$(CONFIG_K3_DMA) += k3dma.o
 obj-$(CONFIG_LPC18XX_DMAMUX) += lpc18xx-dmamux.o
+obj-$(CONFIG_MILBEAUT_HDMAC) += milbeaut-hdmac.o
 obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o
 obj-$(CONFIG_MMP_TDMA) += mmp_tdma.o
 obj-$(CONFIG_MOXART_DMA) += moxart-dma.o
diff --git a/drivers/dma/milbeaut-hdmac.c b/drivers/dma/milbeaut-hdmac.c
new file mode 100644
index 000000000000..9c9fabdf8cdc
--- /dev/null
+++ b/drivers/dma/milbeaut-hdmac.c
@@ -0,0 +1,572 @@ 
+// SPDX-License-Identifier: GPL-2.0
+//
+// Copyright (C) 2019 Linaro Ltd.
+// Copyright (C) 2019 Socionext Inc.
+
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/iopoll.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/bitfield.h>
+
+#include "virt-dma.h"
+
+#define MLB_HDMAC_DMACR		0x0	/* global */
+#define MLB_HDMAC_DE		BIT(31)
+#define MLB_HDMAC_DS		BIT(30)
+#define MLB_HDMAC_PR		BIT(28)
+#define MLB_HDMAC_DH		GENMASK(27, 24)
+
+#define MLB_HDMAC_CH_STRIDE	0x10
+
+#define MLB_HDMAC_DMACA		0x0	/* channel */
+#define MLB_HDMAC_EB		BIT(31)
+#define MLB_HDMAC_PB		BIT(30)
+#define MLB_HDMAC_ST		BIT(29)
+#define MLB_HDMAC_IS		GENMASK(28, 24)
+#define MLB_HDMAC_BT		GENMASK(23, 20)
+#define MLB_HDMAC_BC		GENMASK(19, 16)
+#define MLB_HDMAC_TC		GENMASK(15, 0)
+#define MLB_HDMAC_DMACB		0x4
+#define MLB_HDMAC_TT		GENMASK(31, 30)
+#define MLB_HDMAC_MS		GENMASK(29, 28)
+#define MLB_HDMAC_TW		GENMASK(27, 26)
+#define MLB_HDMAC_FS		BIT(25)
+#define MLB_HDMAC_FD		BIT(24)
+#define MLB_HDMAC_RC		BIT(23)
+#define MLB_HDMAC_RS		BIT(22)
+#define MLB_HDMAC_RD		BIT(21)
+#define MLB_HDMAC_EI		BIT(20)
+#define MLB_HDMAC_CI		BIT(19)
+#define MLB_HDMAC_SS		GENMASK(18, 16)
+#define MLB_HDMAC_SP		GENMASK(15, 12)
+#define MLB_HDMAC_DP		GENMASK(11, 8)
+#define MLB_HDMAC_DMACSA	0x8
+#define MLB_HDMAC_DMACDA	0xc
+
+#define MLB_HDMAC_BUSWIDTHS		(BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
+					BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
+					BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))
+
+struct milbeaut_hdmac_desc {
+	struct virt_dma_desc vd;
+	struct scatterlist *sgl;
+	unsigned int sg_len;
+	unsigned int sg_cur;
+	enum dma_transfer_direction dir;
+};
+
+struct milbeaut_hdmac_chan {
+	struct virt_dma_chan vc;
+	struct milbeaut_hdmac_device *mdev;
+	struct milbeaut_hdmac_desc *md;
+	void __iomem *reg_ch_base;
+	unsigned int slave_id;
+	struct dma_slave_config	cfg;
+};
+
+struct milbeaut_hdmac_device {
+	struct dma_device ddev;
+	struct clk *clk;
+	void __iomem *reg_base;
+	struct milbeaut_hdmac_chan channels[0];
+};
+
+static struct milbeaut_hdmac_chan *
+to_milbeaut_hdmac_chan(struct virt_dma_chan *vc)
+{
+	return container_of(vc, struct milbeaut_hdmac_chan, vc);
+}
+
+static struct milbeaut_hdmac_desc *
+to_milbeaut_hdmac_desc(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct milbeaut_hdmac_desc, vd);
+}
+
+/* mc->vc.lock must be held by caller */
+static struct milbeaut_hdmac_desc *
+milbeaut_hdmac_next_desc(struct milbeaut_hdmac_chan *mc)
+{
+	struct virt_dma_desc *vd;
+
+	vd = vchan_next_desc(&mc->vc);
+	if (!vd) {
+		mc->md = NULL;
+		return NULL;
+	}
+
+	list_del(&vd->node);
+
+	mc->md = to_milbeaut_hdmac_desc(vd);
+
+	return mc->md;
+}
+
+/* mc->vc.lock must be held by caller */
+static void milbeaut_chan_start(struct milbeaut_hdmac_chan *mc,
+				struct milbeaut_hdmac_desc *md)
+{
+	struct scatterlist *sg;
+	u32  cb, ca, src_addr, dest_addr, len;
+	u32 width, burst;
+
+	sg = &md->sgl[md->sg_cur];
+	len = sg_dma_len(sg);
+
+	cb = MLB_HDMAC_CI | MLB_HDMAC_EI;
+	if (md->dir == DMA_MEM_TO_DEV) {
+		cb |= MLB_HDMAC_FD;
+		width = mc->cfg.dst_addr_width;
+		burst = mc->cfg.dst_maxburst;
+		src_addr = sg_dma_address(sg);
+		dest_addr = mc->cfg.dst_addr;
+	} else {
+		cb |= MLB_HDMAC_FS;
+		width = mc->cfg.src_addr_width;
+		burst = mc->cfg.src_maxburst;
+		src_addr = mc->cfg.src_addr;
+		dest_addr = sg_dma_address(sg);
+	}
+	cb |= FIELD_PREP(MLB_HDMAC_TW, (width >> 1));
+	cb |= FIELD_PREP(MLB_HDMAC_MS, 2);
+
+	writel_relaxed(src_addr, mc->reg_ch_base + MLB_HDMAC_DMACSA);
+	writel_relaxed(dest_addr, mc->reg_ch_base + MLB_HDMAC_DMACDA);
+	writel_relaxed(cb, mc->reg_ch_base + MLB_HDMAC_DMACB);
+
+	ca = FIELD_PREP(MLB_HDMAC_IS, mc->slave_id);
+	if (burst == 16)
+		ca |= FIELD_PREP(MLB_HDMAC_BT, 0xf);
+	else if (burst == 8)
+		ca |= FIELD_PREP(MLB_HDMAC_BT, 0xd);
+	else if (burst == 4)
+		ca |= FIELD_PREP(MLB_HDMAC_BT, 0xb);
+	burst *= width;
+	ca |= FIELD_PREP(MLB_HDMAC_TC, (len / burst - 1));
+	writel_relaxed(ca, mc->reg_ch_base + MLB_HDMAC_DMACA);
+	ca |= MLB_HDMAC_EB;
+	writel_relaxed(ca, mc->reg_ch_base + MLB_HDMAC_DMACA);
+}
+
+/* mc->vc.lock must be held by caller */
+static void milbeaut_hdmac_start(struct milbeaut_hdmac_chan *mc)
+{
+	struct milbeaut_hdmac_desc *md;
+
+	md = milbeaut_hdmac_next_desc(mc);
+	if (md)
+		milbeaut_chan_start(mc, md);
+}
+
+static irqreturn_t milbeaut_hdmac_interrupt(int irq, void *dev_id)
+{
+	struct milbeaut_hdmac_chan *mc = dev_id;
+	struct milbeaut_hdmac_desc *md;
+	irqreturn_t ret = IRQ_HANDLED;
+	u32 val;
+
+	spin_lock(&mc->vc.lock);
+
+	/* Ack and Disable irqs */
+	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACB);
+	val &= ~(FIELD_PREP(MLB_HDMAC_SS, 0x7));
+	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACB);
+	val &= ~MLB_HDMAC_EI;
+	val &= ~MLB_HDMAC_CI;
+	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACB);
+
+	md = mc->md;
+	if (!md)
+		goto out;
+
+	md->sg_cur++;
+
+	if (md->sg_cur >= md->sg_len) {
+		vchan_cookie_complete(&md->vd);
+		md = milbeaut_hdmac_next_desc(mc);
+		if (!md)
+			goto out;
+	}
+
+	milbeaut_chan_start(mc, md);
+
+out:
+	spin_unlock(&mc->vc.lock);
+	return ret;
+}
+
+static void milbeaut_hdmac_free_chan_resources(struct dma_chan *chan)
+{
+	vchan_free_chan_resources(to_virt_chan(chan));
+}
+
+static int
+milbeaut_hdmac_chan_config(struct dma_chan *chan, struct dma_slave_config *cfg)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
+
+	spin_lock(&mc->vc.lock);
+	mc->cfg = *cfg;
+	spin_unlock(&mc->vc.lock);
+
+	return 0;
+}
+
+static int milbeaut_hdmac_chan_pause(struct dma_chan *chan)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
+	u32 val;
+
+	spin_lock(&mc->vc.lock);
+	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
+	val |= MLB_HDMAC_PB;
+	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);
+	spin_unlock(&mc->vc.lock);
+
+	return 0;
+}
+
+static int milbeaut_hdmac_chan_resume(struct dma_chan *chan)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
+	u32 val;
+
+	spin_lock(&mc->vc.lock);
+	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
+	val &= ~MLB_HDMAC_PB;
+	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);
+	spin_unlock(&mc->vc.lock);
+
+	return 0;
+}
+
+static struct dma_async_tx_descriptor *
+milbeaut_hdmac_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 virt_dma_chan *vc = to_virt_chan(chan);
+	struct milbeaut_hdmac_desc *md;
+
+	if (!is_slave_direction(direction))
+		return NULL;
+
+	md = kzalloc(sizeof(*md), GFP_NOWAIT);
+	if (!md)
+		return NULL;
+
+	md->sgl = sgl;
+	md->sg_len = sg_len;
+	md->dir = direction;
+
+	return vchan_tx_prep(vc, &md->vd, flags);
+}
+
+static int milbeaut_hdmac_terminate_all(struct dma_chan *chan)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
+	unsigned long flags;
+	int ret = 0;
+	u32 val;
+
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&vc->lock, flags);
+
+	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
+	val &= ~MLB_HDMAC_EB; /* disable the channel */
+	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);
+
+	if (mc->md) {
+		vchan_terminate_vdesc(&mc->md->vd);
+		mc->md = NULL;
+	}
+
+	vchan_get_all_descriptors(vc, &head);
+
+	spin_unlock_irqrestore(&vc->lock, flags);
+
+	vchan_dma_desc_free_list(vc, &head);
+
+	return ret;
+}
+
+static void milbeaut_hdmac_synchronize(struct dma_chan *chan)
+{
+	vchan_synchronize(to_virt_chan(chan));
+}
+
+static enum dma_status milbeaut_hdmac_tx_status(struct dma_chan *chan,
+						dma_cookie_t cookie,
+						struct dma_tx_state *txstate)
+{
+	struct virt_dma_chan *vc;
+	struct virt_dma_desc *vd;
+	struct milbeaut_hdmac_chan *mc;
+	struct milbeaut_hdmac_desc *md = NULL;
+	enum dma_status stat;
+	unsigned long flags;
+	int i;
+
+	stat = dma_cookie_status(chan, cookie, txstate);
+	/* Return immediately if we do not need to compute the residue. */
+	if (stat == DMA_COMPLETE || !txstate)
+		return stat;
+
+	vc = to_virt_chan(chan);
+
+	spin_lock_irqsave(&vc->lock, flags);
+
+	mc = to_milbeaut_hdmac_chan(vc);
+
+	/* residue from the on-flight chunk */
+	if (mc->md && mc->md->vd.tx.cookie == cookie) {
+		struct scatterlist *sg;
+		u32 done;
+
+		md = mc->md;
+		sg = &md->sgl[md->sg_cur];
+
+		if (md->dir == DMA_DEV_TO_MEM)
+			done = readl_relaxed(mc->reg_ch_base
+					     + MLB_HDMAC_DMACDA);
+		else
+			done = readl_relaxed(mc->reg_ch_base
+					     + MLB_HDMAC_DMACSA);
+		done -= sg_dma_address(sg);
+
+		txstate->residue = -done;
+	}
+
+	if (!md) {
+		vd = vchan_find_desc(vc, cookie);
+		if (vd)
+			md = to_milbeaut_hdmac_desc(vd);
+	}
+
+	if (md) {
+		/* residue from the queued chunks */
+		for (i = md->sg_cur; i < md->sg_len; i++)
+			txstate->residue += sg_dma_len(&md->sgl[i]);
+	}
+
+	spin_unlock_irqrestore(&vc->lock, flags);
+
+	return stat;
+}
+
+static void milbeaut_hdmac_issue_pending(struct dma_chan *chan)
+{
+	struct virt_dma_chan *vc = to_virt_chan(chan);
+	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&vc->lock, flags);
+
+	if (vchan_issue_pending(vc) && !mc->md)
+		milbeaut_hdmac_start(mc);
+
+	spin_unlock_irqrestore(&vc->lock, flags);
+}
+
+static void milbeaut_hdmac_desc_free(struct virt_dma_desc *vd)
+{
+	kfree(to_milbeaut_hdmac_desc(vd));
+}
+
+static struct dma_chan *
+milbeaut_hdmac_xlate(struct of_phandle_args *dma_spec, struct of_dma *of_dma)
+{
+	struct milbeaut_hdmac_device *mdev = of_dma->of_dma_data;
+	struct milbeaut_hdmac_chan *mc;
+	struct virt_dma_chan *vc;
+	struct dma_chan *chan;
+
+	if (dma_spec->args_count != 1)
+		return NULL;
+
+	chan = dma_get_any_slave_channel(&mdev->ddev);
+	if (!chan)
+		return NULL;
+
+	vc = to_virt_chan(chan);
+	mc = to_milbeaut_hdmac_chan(vc);
+	mc->slave_id = dma_spec->args[0];
+
+	return chan;
+}
+
+static int milbeaut_hdmac_chan_init(struct platform_device *pdev,
+				    struct milbeaut_hdmac_device *mdev,
+				    int chan_id)
+{
+	struct device *dev = &pdev->dev;
+	struct milbeaut_hdmac_chan *mc = &mdev->channels[chan_id];
+	char *irq_name;
+	int irq, ret;
+
+	irq = platform_get_irq(pdev, chan_id);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "failed to get IRQ number for ch%d\n",
+			chan_id);
+		return irq;
+	}
+
+	irq_name = devm_kasprintf(dev, GFP_KERNEL, "milbeaut-hdmac-%d",
+				  chan_id);
+	if (!irq_name)
+		return -ENOMEM;
+
+	ret = devm_request_irq(dev, irq, milbeaut_hdmac_interrupt,
+			       IRQF_SHARED, irq_name, mc);
+	if (ret)
+		return ret;
+
+	mc->mdev = mdev;
+	mc->reg_ch_base = mdev->reg_base + MLB_HDMAC_CH_STRIDE * (chan_id + 1);
+	mc->vc.desc_free = milbeaut_hdmac_desc_free;
+	vchan_init(&mc->vc, &mdev->ddev);
+
+	return 0;
+}
+
+static int milbeaut_hdmac_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct milbeaut_hdmac_device *mdev;
+	struct dma_device *ddev;
+	struct resource *res;
+	int nr_chans, ret, i;
+
+	nr_chans = platform_irq_count(pdev);
+	if (nr_chans < 0)
+		return nr_chans;
+
+	ret = dma_set_mask(dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
+
+	mdev = devm_kzalloc(dev, struct_size(mdev, channels, nr_chans),
+			    GFP_KERNEL);
+	if (!mdev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mdev->reg_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(mdev->reg_base))
+		return PTR_ERR(mdev->reg_base);
+
+	mdev->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(mdev->clk)) {
+		dev_err(dev, "failed to get clock\n");
+		return PTR_ERR(mdev->clk);
+	}
+
+	ret = clk_prepare_enable(mdev->clk);
+	if (ret)
+		return ret;
+
+	ddev = &mdev->ddev;
+	ddev->dev = dev;
+	dma_cap_set(DMA_PRIVATE, ddev->cap_mask);
+	ddev->src_addr_widths = MLB_HDMAC_BUSWIDTHS;
+	ddev->dst_addr_widths = MLB_HDMAC_BUSWIDTHS;
+	ddev->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM);
+	ddev->device_free_chan_resources = milbeaut_hdmac_free_chan_resources;
+	ddev->device_config = milbeaut_hdmac_chan_config;
+	ddev->device_pause = milbeaut_hdmac_chan_pause;
+	ddev->device_resume = milbeaut_hdmac_chan_resume;
+	ddev->device_prep_slave_sg = milbeaut_hdmac_prep_slave_sg;
+	ddev->device_terminate_all = milbeaut_hdmac_terminate_all;
+	ddev->device_synchronize = milbeaut_hdmac_synchronize;
+	ddev->device_tx_status = milbeaut_hdmac_tx_status;
+	ddev->device_issue_pending = milbeaut_hdmac_issue_pending;
+	INIT_LIST_HEAD(&ddev->channels);
+
+	for (i = 0; i < nr_chans; i++) {
+		ret = milbeaut_hdmac_chan_init(pdev, mdev, i);
+		if (ret)
+			goto disable_clk;
+	}
+
+	ret = dma_async_device_register(ddev);
+	if (ret)
+		goto disable_clk;
+
+	ret = of_dma_controller_register(dev->of_node,
+					 milbeaut_hdmac_xlate, mdev);
+	if (ret)
+		goto unregister_dmac;
+
+	platform_set_drvdata(pdev, mdev);
+
+	return 0;
+
+unregister_dmac:
+	dma_async_device_unregister(ddev);
+disable_clk:
+	clk_disable_unprepare(mdev->clk);
+
+	return ret;
+}
+
+static int milbeaut_hdmac_remove(struct platform_device *pdev)
+{
+	struct milbeaut_hdmac_device *mdev = platform_get_drvdata(pdev);
+	struct dma_chan *chan;
+	int ret;
+
+	/*
+	 * Before reaching here, almost all descriptors have been freed by the
+	 * ->device_free_chan_resources() hook. However, each channel might
+	 * be still holding one descriptor that was on-flight at that moment.
+	 * Terminate it to make sure this hardware is no longer running. Then,
+	 * free the channel resources once again to avoid memory leak.
+	 */
+	list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
+		ret = dmaengine_terminate_sync(chan);
+		if (ret)
+			return ret;
+		milbeaut_hdmac_free_chan_resources(chan);
+	}
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&mdev->ddev);
+	clk_disable_unprepare(mdev->clk);
+
+	return 0;
+}
+
+static const struct of_device_id milbeaut_hdmac_match[] = {
+	{ .compatible = "socionext,milbeaut-m10v-hdmac" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, milbeaut_hdmac_match);
+
+static struct platform_driver milbeaut_hdmac_driver = {
+	.probe = milbeaut_hdmac_probe,
+	.remove = milbeaut_hdmac_remove,
+	.driver = {
+		.name = "milbeaut-m10v-hdmac",
+		.of_match_table = milbeaut_hdmac_match,
+	},
+};
+module_platform_driver(milbeaut_hdmac_driver);
+
+MODULE_DESCRIPTION("Milbeaut HDMAC DmaEngine driver");
+MODULE_LICENSE("GPL v2");