dmaengine: dw: Split DW and iDMA 32-bit operations

Here is a kinda big refactoring that should have been done
in the first place, when Intel iDMA 32-bit support appeared.

It splits operations which are different to Synopsys DesignWare and
Intel iDMA 32-bit controllers.

No functional change intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

8 files changed, 339 insertions, 179 deletions

diff --git a/drivers/dma/dw/Makefile b/drivers/dma/dw/Makefile
index 2b949c2e4504..63ed895c09aa 100644
--- a/drivers/dma/dw/Makefile
+++ b/drivers/dma/dw/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_DW_DMAC_CORE)	+= dw_dmac_core.o
-dw_dmac_core-objs	:= core.o
+dw_dmac_core-objs	:= core.o dw.o idma32.o
 
 obj-$(CONFIG_DW_DMAC)		+= dw_dmac.o
 dw_dmac-objs		:= platform.o
diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
index 4982e443869c..8a581d86ea8d 100644
--- a/drivers/dma/dw/core.c
+++ b/drivers/dma/dw/core.c
@@ -138,44 +138,6 @@ static void dwc_desc_put(struct dw_dma_chan *dwc, struct dw_desc *desc)
 	dwc->descs_allocated--;
 }
 
-static void dwc_initialize_chan_idma32(struct dw_dma_chan *dwc)
-{
-	u32 cfghi = 0;
-	u32 cfglo = 0;
-
-	/* Set default burst alignment */
-	cfglo |= IDMA32C_CFGL_DST_BURST_ALIGN | IDMA32C_CFGL_SRC_BURST_ALIGN;
-
-	/* Low 4 bits of the request lines */
-	cfghi |= IDMA32C_CFGH_DST_PER(dwc->dws.dst_id & 0xf);
-	cfghi |= IDMA32C_CFGH_SRC_PER(dwc->dws.src_id & 0xf);
-
-	/* Request line extension (2 bits) */
-	cfghi |= IDMA32C_CFGH_DST_PER_EXT(dwc->dws.dst_id >> 4 & 0x3);
-	cfghi |= IDMA32C_CFGH_SRC_PER_EXT(dwc->dws.src_id >> 4 & 0x3);
-
-	channel_writel(dwc, CFG_LO, cfglo);
-	channel_writel(dwc, CFG_HI, cfghi);
-}
-
-static void dwc_initialize_chan_dw(struct dw_dma_chan *dwc)
-{
-	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
-	u32 cfghi = DWC_CFGH_FIFO_MODE;
-	u32 cfglo = DWC_CFGL_CH_PRIOR(dwc->priority);
-	bool hs_polarity = dwc->dws.hs_polarity;
-
-	cfghi |= DWC_CFGH_DST_PER(dwc->dws.dst_id);
-	cfghi |= DWC_CFGH_SRC_PER(dwc->dws.src_id);
-	cfghi |= DWC_CFGH_PROTCTL(dw->pdata->protctl);
-
-	/* Set polarity of handshake interface */
-	cfglo |= hs_polarity ? DWC_CFGL_HS_DST_POL | DWC_CFGL_HS_SRC_POL : 0;
-
-	channel_writel(dwc, CFG_LO, cfglo);
-	channel_writel(dwc, CFG_HI, cfghi);
-}
-
 static void dwc_initialize(struct dw_dma_chan *dwc)
 {
 	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
@@ -183,10 +145,7 @@ static void dwc_initialize(struct dw_dma_chan *dwc)
 	if (test_bit(DW_DMA_IS_INITIALIZED, &dwc->flags))
 		return;
 
-	if (dw->pdata->is_idma32)
-		dwc_initialize_chan_idma32(dwc);
-	else
-		dwc_initialize_chan_dw(dwc);
+	dw->initialize_chan(dwc);
 
 	/* Enable interrupts */
 	channel_set_bit(dw, MASK.XFER, dwc->mask);
@@ -215,37 +174,6 @@ static inline void dwc_chan_disable(struct dw_dma *dw, struct dw_dma_chan *dwc)
 		cpu_relax();
 }
 
-static u32 bytes2block(struct dw_dma_chan *dwc, size_t bytes,
-			  unsigned int width, size_t *len)
-{
-	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
-	u32 block;
-
-	/* Always in bytes for iDMA 32-bit */
-	if (dw->pdata->is_idma32)
-		width = 0;
-
-	if ((bytes >> width) > dwc->block_size) {
-		block = dwc->block_size;
-		*len = block << width;
-	} else {
-		block = bytes >> width;
-		*len = bytes;
-	}
-
-	return block;
-}
-
-static size_t block2bytes(struct dw_dma_chan *dwc, u32 block, u32 width)
-{
-	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
-
-	if (dw->pdata->is_idma32)
-		return IDMA32C_CTLH_BLOCK_TS(block);
-
-	return DWC_CTLH_BLOCK_TS(block) << width;
-}
-
 /*----------------------------------------------------------------------*/
 
 /* Perform single block transfer */
@@ -391,10 +319,11 @@ static void dwc_complete_all(struct dw_dma *dw, struct dw_dma_chan *dwc)
 /* Returns how many bytes were already received from source */
 static inline u32 dwc_get_sent(struct dw_dma_chan *dwc)
 {
+	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
 	u32 ctlhi = channel_readl(dwc, CTL_HI);
 	u32 ctllo = channel_readl(dwc, CTL_LO);
 
-	return block2bytes(dwc, ctlhi, ctllo >> 4 & 7);
+	return dw->block2bytes(dwc, ctlhi, ctllo >> 4 & 7);
 }
 
 static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
@@ -651,7 +580,7 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 	unsigned int		src_width;
 	unsigned int		dst_width;
 	unsigned int		data_width = dw->pdata->data_width[m_master];
-	u32			ctllo;
+	u32			ctllo, ctlhi;
 	u8			lms = DWC_LLP_LMS(m_master);
 
 	dev_vdbg(chan2dev(chan),
@@ -680,10 +609,12 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
 		if (!desc)
 			goto err_desc_get;
 
+		ctlhi = dw->bytes2block(dwc, len - offset, src_width, &xfer_count);
+
 		lli_write(desc, sar, src + offset);
 		lli_write(desc, dar, dest + offset);
 		lli_write(desc, ctllo, ctllo);
-		lli_write(desc, ctlhi, bytes2block(dwc, len - offset, src_width, &xfer_count));
+		lli_write(desc, ctlhi, ctlhi);
 		desc->len = xfer_count;
 
 		if (!first) {
@@ -721,7 +652,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 	struct dma_slave_config	*sconfig = &dwc->dma_sconfig;
 	struct dw_desc		*prev;
 	struct dw_desc		*first;
-	u32			ctllo;
+	u32			ctllo, ctlhi;
 	u8			m_master = dwc->dws.m_master;
 	u8			lms = DWC_LLP_LMS(m_master);
 	dma_addr_t		reg;
@@ -768,9 +699,11 @@ slave_sg_todev_fill_desc:
 			if (!desc)
 				goto err_desc_get;
 
+			ctlhi = dw->bytes2block(dwc, len, mem_width, &dlen);
+
 			lli_write(desc, sar, mem);
 			lli_write(desc, dar, reg);
-			lli_write(desc, ctlhi, bytes2block(dwc, len, mem_width, &dlen));
+			lli_write(desc, ctlhi, ctlhi);
 			lli_write(desc, ctllo, ctllo | DWC_CTLL_SRC_WIDTH(mem_width));
 			desc->len = dlen;
 
@@ -814,9 +747,11 @@ slave_sg_fromdev_fill_desc:
 			if (!desc)
 				goto err_desc_get;
 
+			ctlhi = dw->bytes2block(dwc, len, reg_width, &dlen);
+
 			lli_write(desc, sar, reg);
 			lli_write(desc, dar, mem);
-			lli_write(desc, ctlhi, bytes2block(dwc, len, reg_width, &dlen));
+			lli_write(desc, ctlhi, ctlhi);
 			mem_width = __ffs(data_width | mem | dlen);
 			lli_write(desc, ctllo, ctllo | DWC_CTLL_DST_WIDTH(mem_width));
 			desc->len = dlen;
@@ -876,22 +811,12 @@ EXPORT_SYMBOL_GPL(dw_dma_filter);
 static int dwc_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
 {
 	struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
-	struct dma_slave_config *sc = &dwc->dma_sconfig;
 	struct dw_dma *dw = to_dw_dma(chan->device);
-	/*
-	 * Fix sconfig's burst size according to dw_dmac. We need to convert
-	 * them as:
-	 * 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.
-	 *
-	 * NOTE: burst size 2 is not supported by DesignWare controller.
-	 *       iDMA 32-bit supports it.
-	 */
-	u32 s = dw->pdata->is_idma32 ? 1 : 2;
 
 	memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
 
-	sc->src_maxburst = sc->src_maxburst > 1 ? fls(sc->src_maxburst) - s : 0;
-	sc->dst_maxburst = sc->dst_maxburst > 1 ? fls(sc->dst_maxburst) - s : 0;
+	dw->encode_maxburst(dwc, &dwc->dma_sconfig.src_maxburst);
+	dw->encode_maxburst(dwc, &dwc->dma_sconfig.dst_maxburst);
 
 	return 0;
 }
@@ -900,16 +825,9 @@ static void dwc_chan_pause(struct dw_dma_chan *dwc, bool drain)
 {
 	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
 	unsigned int		count = 20;	/* timeout iterations */
-	u32			cfglo;
 
-	cfglo = channel_readl(dwc, CFG_LO);
-	if (dw->pdata->is_idma32) {
-		if (drain)
-			cfglo |= IDMA32C_CFGL_CH_DRAIN;
-		else
-			cfglo &= ~IDMA32C_CFGL_CH_DRAIN;
-	}
-	channel_writel(dwc, CFG_LO, cfglo | DWC_CFGL_CH_SUSP);
+	dw->suspend_chan(dwc, drain);
+
 	while (!(channel_readl(dwc, CFG_LO) & DWC_CFGL_FIFO_EMPTY) && count--)
 		udelay(2);
 
@@ -1058,33 +976,7 @@ static void dwc_issue_pending(struct dma_chan *chan)
 
 /*----------------------------------------------------------------------*/
 
-/*
- * Program FIFO size of channels.
- *
- * By default full FIFO (512 bytes) is assigned to channel 0. Here we
- * slice FIFO on equal parts between channels.
- */
-static void idma32_fifo_partition(struct dw_dma *dw)
-{
-	u64 value = IDMA32C_FP_PSIZE_CH0(64) | IDMA32C_FP_PSIZE_CH1(64) |
-		    IDMA32C_FP_UPDATE;
-	u64 fifo_partition = 0;
-
-	if (!dw->pdata->is_idma32)
-		return;
-
-	/* Fill FIFO_PARTITION low bits (Channels 0..1, 4..5) */
-	fifo_partition |= value << 0;
-
-	/* Fill FIFO_PARTITION high bits (Channels 2..3, 6..7) */
-	fifo_partition |= value << 32;
-
-	/* Program FIFO Partition registers - 64 bytes per channel */
-	idma32_writeq(dw, FIFO_PARTITION1, fifo_partition);
-	idma32_writeq(dw, FIFO_PARTITION0, fifo_partition);
-}
-
-static void dw_dma_off(struct dw_dma *dw)
+void do_dw_dma_off(struct dw_dma *dw)
 {
 	unsigned int i;
 
@@ -1103,7 +995,7 @@ static void dw_dma_off(struct dw_dma *dw)
 		clear_bit(DW_DMA_IS_INITIALIZED, &dw->chan[i].flags);
 }
 
-static void dw_dma_on(struct dw_dma *dw)
+void do_dw_dma_on(struct dw_dma *dw)
 {
 	dma_writel(dw, CFG, DW_CFG_DMA_EN);
 }
@@ -1139,7 +1031,7 @@ static int dwc_alloc_chan_resources(struct dma_chan *chan)
 
 	/* Enable controller here if needed */
 	if (!dw->in_use)
-		dw_dma_on(dw);
+		do_dw_dma_on(dw);
 	dw->in_use |= dwc->mask;
 
 	return 0;
@@ -1177,30 +1069,25 @@ static void dwc_free_chan_resources(struct dma_chan *chan)
 	/* Disable controller in case it was a last user */
 	dw->in_use &= ~dwc->mask;
 	if (!dw->in_use)
-		dw_dma_off(dw);
+		do_dw_dma_off(dw);
 
 	dev_vdbg(chan2dev(chan), "%s: done\n", __func__);
 }
 
-int dw_dma_probe(struct dw_dma_chip *chip)
+int do_dma_probe(struct dw_dma_chip *chip)
 {
+	struct dw_dma *dw = chip->dw;
 	struct dw_dma_platform_data *pdata;
-	struct dw_dma		*dw;
 	bool			autocfg = false;
 	unsigned int		dw_params;
 	unsigned int		i;
 	int			err;
 
-	dw = devm_kzalloc(chip->dev, sizeof(*dw), GFP_KERNEL);
-	if (!dw)
-		return -ENOMEM;
-
 	dw->pdata = devm_kzalloc(chip->dev, sizeof(*dw->pdata), GFP_KERNEL);
 	if (!dw->pdata)
 		return -ENOMEM;
 
 	dw->regs = chip->regs;
-	chip->dw = dw;
 
 	pm_runtime_get_sync(chip->dev);
 
@@ -1250,15 +1137,10 @@ int dw_dma_probe(struct dw_dma_chip *chip)
 	dw->all_chan_mask = (1 << pdata->nr_channels) - 1;
 
 	/* Force dma off, just in case */
-	dw_dma_off(dw);
-
-	idma32_fifo_partition(dw);
+	dw->disable(dw);
 
 	/* Device and instance ID for IRQ and DMA pool */
-	if (pdata->is_idma32)
-		snprintf(dw->name, sizeof(dw->name), "idma32:dmac%d", chip->id);
-	else
-		snprintf(dw->name, sizeof(dw->name), "dw:dmac%d", chip->id);
+	dw->set_device_name(dw, chip->id);
 
 	/* Create a pool of consistent memory blocks for hardware descriptors */
 	dw->desc_pool = dmam_pool_create(dw->name, chip->dev,
@@ -1380,16 +1262,15 @@ err_pdata:
 	pm_runtime_put_sync_suspend(chip->dev);
 	return err;
 }
-EXPORT_SYMBOL_GPL(dw_dma_probe);
 
-int dw_dma_remove(struct dw_dma_chip *chip)
+int do_dma_remove(struct dw_dma_chip *chip)
 {
 	struct dw_dma		*dw = chip->dw;
 	struct dw_dma_chan	*dwc, *_dwc;
 
 	pm_runtime_get_sync(chip->dev);
 
-	dw_dma_off(dw);
+	do_dw_dma_off(dw);
 	dma_async_device_unregister(&dw->dma);
 
 	free_irq(chip->irq, dw);
@@ -1404,27 +1285,24 @@ int dw_dma_remove(struct dw_dma_chip *chip)
 	pm_runtime_put_sync_suspend(chip->dev);
 	return 0;
 }
-EXPORT_SYMBOL_GPL(dw_dma_remove);
 
-int dw_dma_disable(struct dw_dma_chip *chip)
+int do_dw_dma_disable(struct dw_dma_chip *chip)
 {
 	struct dw_dma *dw = chip->dw;
 
-	dw_dma_off(dw);
+	dw->disable(dw);
 	return 0;
 }
-EXPORT_SYMBOL_GPL(dw_dma_disable);
+EXPORT_SYMBOL_GPL(do_dw_dma_disable);
 
-int dw_dma_enable(struct dw_dma_chip *chip)
+int do_dw_dma_enable(struct dw_dma_chip *chip)
 {
 	struct dw_dma *dw = chip->dw;
 
-	idma32_fifo_partition(dw);
-
-	dw_dma_on(dw);
+	dw->enable(dw);
 	return 0;
 }
-EXPORT_SYMBOL_GPL(dw_dma_enable);
+EXPORT_SYMBOL_GPL(do_dw_dma_enable);
 
 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("Synopsys DesignWare DMA Controller core driver");
diff --git a/drivers/dma/dw/dw.c b/drivers/dma/dw/dw.c
new file mode 100644
index 000000000000..977aa28bf81d
--- /dev/null
+++ b/drivers/dma/dw/dw.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2007-2008 Atmel Corporation
+// Copyright (C) 2010-2011 ST Microelectronics
+// Copyright (C) 2013,2018 Intel Corporation
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "internal.h"
+
+static void dw_dma_initialize_chan(struct dw_dma_chan *dwc)
+{
+	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+	u32 cfghi = DWC_CFGH_FIFO_MODE;
+	u32 cfglo = DWC_CFGL_CH_PRIOR(dwc->priority);
+	bool hs_polarity = dwc->dws.hs_polarity;
+
+	cfghi |= DWC_CFGH_DST_PER(dwc->dws.dst_id);
+	cfghi |= DWC_CFGH_SRC_PER(dwc->dws.src_id);
+	cfghi |= DWC_CFGH_PROTCTL(dw->pdata->protctl);
+
+	/* Set polarity of handshake interface */
+	cfglo |= hs_polarity ? DWC_CFGL_HS_DST_POL | DWC_CFGL_HS_SRC_POL : 0;
+
+	channel_writel(dwc, CFG_LO, cfglo);
+	channel_writel(dwc, CFG_HI, cfghi);
+}
+
+static void dw_dma_suspend_chan(struct dw_dma_chan *dwc, bool drain)
+{
+	u32 cfglo = channel_readl(dwc, CFG_LO);
+
+	channel_writel(dwc, CFG_LO, cfglo | DWC_CFGL_CH_SUSP);
+}
+
+static u32 dw_dma_bytes2block(struct dw_dma_chan *dwc,
+			      size_t bytes, unsigned int width, size_t *len)
+{
+	u32 block;
+
+	if ((bytes >> width) > dwc->block_size) {
+		block = dwc->block_size;
+		*len = dwc->block_size << width;
+	} else {
+		block = bytes >> width;
+		*len = bytes;
+	}
+
+	return block;
+}
+
+static size_t dw_dma_block2bytes(struct dw_dma_chan *dwc, u32 block, u32 width)
+{
+	return DWC_CTLH_BLOCK_TS(block) << width;
+}
+
+static void dw_dma_encode_maxburst(struct dw_dma_chan *dwc, u32 *maxburst)
+{
+	/*
+	 * Fix burst size according to dw_dmac. We need to convert them as:
+	 * 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.
+	 */
+	*maxburst = *maxburst > 1 ? fls(*maxburst) - 2 : 0;
+}
+
+static void dw_dma_set_device_name(struct dw_dma *dw, int id)
+{
+	snprintf(dw->name, sizeof(dw->name), "dw:dmac%d", id);
+}
+
+static void dw_dma_disable(struct dw_dma *dw)
+{
+	do_dw_dma_off(dw);
+}
+
+static void dw_dma_enable(struct dw_dma *dw)
+{
+	do_dw_dma_on(dw);
+}
+
+int dw_dma_probe(struct dw_dma_chip *chip)
+{
+	struct dw_dma *dw;
+
+	dw = devm_kzalloc(chip->dev, sizeof(*dw), GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+
+	/* Channel operations */
+	dw->initialize_chan = dw_dma_initialize_chan;
+	dw->suspend_chan = dw_dma_suspend_chan;
+	dw->encode_maxburst = dw_dma_encode_maxburst;
+	dw->bytes2block = dw_dma_bytes2block;
+	dw->block2bytes = dw_dma_block2bytes;
+
+	/* Device operations */
+	dw->set_device_name = dw_dma_set_device_name;
+	dw->disable = dw_dma_disable;
+	dw->enable = dw_dma_enable;
+
+	chip->dw = dw;
+	return do_dma_probe(chip);
+}
+EXPORT_SYMBOL_GPL(dw_dma_probe);
+
+int dw_dma_remove(struct dw_dma_chip *chip)
+{
+	return do_dma_remove(chip);
+}
+EXPORT_SYMBOL_GPL(dw_dma_remove);
diff --git a/drivers/dma/dw/idma32.c b/drivers/dma/dw/idma32.c
new file mode 100644
index 000000000000..8707830f39ad
--- /dev/null
+++ b/drivers/dma/dw/idma32.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2013,2018 Intel Corporation
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "internal.h"
+
+static void idma32_initialize_chan(struct dw_dma_chan *dwc)
+{
+	u32 cfghi = 0;
+	u32 cfglo = 0;
+
+	/* Set default burst alignment */
+	cfglo |= IDMA32C_CFGL_DST_BURST_ALIGN | IDMA32C_CFGL_SRC_BURST_ALIGN;
+
+	/* Low 4 bits of the request lines */
+	cfghi |= IDMA32C_CFGH_DST_PER(dwc->dws.dst_id & 0xf);
+	cfghi |= IDMA32C_CFGH_SRC_PER(dwc->dws.src_id & 0xf);
+
+	/* Request line extension (2 bits) */
+	cfghi |= IDMA32C_CFGH_DST_PER_EXT(dwc->dws.dst_id >> 4 & 0x3);
+	cfghi |= IDMA32C_CFGH_SRC_PER_EXT(dwc->dws.src_id >> 4 & 0x3);
+
+	channel_writel(dwc, CFG_LO, cfglo);
+	channel_writel(dwc, CFG_HI, cfghi);
+}
+
+static void idma32_suspend_chan(struct dw_dma_chan *dwc, bool drain)
+{
+	u32 cfglo = channel_readl(dwc, CFG_LO);
+
+	if (drain)
+		cfglo |= IDMA32C_CFGL_CH_DRAIN;
+	else
+		cfglo &= ~IDMA32C_CFGL_CH_DRAIN;
+
+	channel_writel(dwc, CFG_LO, cfglo | DWC_CFGL_CH_SUSP);
+}
+
+static u32 idma32_bytes2block(struct dw_dma_chan *dwc,
+			      size_t bytes, unsigned int width, size_t *len)
+{
+	u32 block;
+
+	if (bytes > dwc->block_size) {
+		block = dwc->block_size;
+		*len = dwc->block_size;
+	} else {
+		block = bytes;
+		*len = bytes;
+	}
+
+	return block;
+}
+
+static size_t idma32_block2bytes(struct dw_dma_chan *dwc, u32 block, u32 width)
+{
+	return IDMA32C_CTLH_BLOCK_TS(block);
+}
+
+static void idma32_encode_maxburst(struct dw_dma_chan *dwc, u32 *maxburst)
+{
+	*maxburst = *maxburst > 1 ? fls(*maxburst) - 1 : 0;
+}
+
+static void idma32_set_device_name(struct dw_dma *dw, int id)
+{
+	snprintf(dw->name, sizeof(dw->name), "idma32:dmac%d", id);
+}
+
+/*
+ * Program FIFO size of channels.
+ *
+ * By default full FIFO (512 bytes) is assigned to channel 0. Here we
+ * slice FIFO on equal parts between channels.
+ */
+static void idma32_fifo_partition(struct dw_dma *dw)
+{
+	u64 value = IDMA32C_FP_PSIZE_CH0(64) | IDMA32C_FP_PSIZE_CH1(64) |
+		    IDMA32C_FP_UPDATE;
+	u64 fifo_partition = 0;
+
+	/* Fill FIFO_PARTITION low bits (Channels 0..1, 4..5) */
+	fifo_partition |= value << 0;
+
+	/* Fill FIFO_PARTITION high bits (Channels 2..3, 6..7) */
+	fifo_partition |= value << 32;
+
+	/* Program FIFO Partition registers - 64 bytes per channel */
+	idma32_writeq(dw, FIFO_PARTITION1, fifo_partition);
+	idma32_writeq(dw, FIFO_PARTITION0, fifo_partition);
+}
+
+static void idma32_disable(struct dw_dma *dw)
+{
+	do_dw_dma_off(dw);
+	idma32_fifo_partition(dw);
+}
+
+static void idma32_enable(struct dw_dma *dw)
+{
+	idma32_fifo_partition(dw);
+	do_dw_dma_on(dw);
+}
+
+int idma32_dma_probe(struct dw_dma_chip *chip)
+{
+	struct dw_dma *dw;
+
+	dw = devm_kzalloc(chip->dev, sizeof(*dw), GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+
+	/* Channel operations */
+	dw->initialize_chan = idma32_initialize_chan;
+	dw->suspend_chan = idma32_suspend_chan;
+	dw->encode_maxburst = idma32_encode_maxburst;
+	dw->bytes2block = idma32_bytes2block;
+	dw->block2bytes = idma32_block2bytes;
+
+	/* Device operations */
+	dw->set_device_name = idma32_set_device_name;
+	dw->disable = idma32_disable;
+	dw->enable = idma32_enable;
+
+	chip->dw = dw;
+	return do_dma_probe(chip);
+}
+EXPORT_SYMBOL_GPL(idma32_dma_probe);
+
+int idma32_dma_remove(struct dw_dma_chip *chip)
+{
+	return do_dma_remove(chip);
+}
+EXPORT_SYMBOL_GPL(idma32_dma_remove);
diff --git a/drivers/dma/dw/internal.h b/drivers/dma/dw/internal.h
index 41439732ff6b..fdcac21ea665 100644
--- a/drivers/dma/dw/internal.h
+++ b/drivers/dma/dw/internal.h
@@ -15,8 +15,14 @@
 
 #include "regs.h"
 
-int dw_dma_disable(struct dw_dma_chip *chip);
-int dw_dma_enable(struct dw_dma_chip *chip);
+int do_dma_probe(struct dw_dma_chip *chip);
+int do_dma_remove(struct dw_dma_chip *chip);
+
+void do_dw_dma_on(struct dw_dma *dw);
+void do_dw_dma_off(struct dw_dma *dw);
+
+int do_dw_dma_disable(struct dw_dma_chip *chip);
+int do_dw_dma_enable(struct dw_dma_chip *chip);
 
 extern bool dw_dma_filter(struct dma_chan *chan, void *param);
 
diff --git a/drivers/dma/dw/pci.c b/drivers/dma/dw/pci.c
index 66d98d7ccad0..e9ba25b4f950 100644
--- a/drivers/dma/dw/pci.c
+++ b/drivers/dma/dw/pci.c
@@ -15,9 +15,17 @@
 
 #include "internal.h"
 
-static struct dw_dma_platform_data mrfld_pdata = {
+struct dw_dma_pci_data {
+	const struct dw_dma_platform_data *pdata;
+	int (*probe)(struct dw_dma_chip *chip);
+};
+
+static const struct dw_dma_pci_data dw_pci_data = {
+	.probe = dw_dma_probe,
+};
+
+static const struct dw_dma_platform_data idma32_pdata = {
 	.nr_channels = 8,
-	.is_idma32 = true,
 	.chan_allocation_order = CHAN_ALLOCATION_ASCENDING,
 	.chan_priority = CHAN_PRIORITY_ASCENDING,
 	.block_size = 131071,
@@ -26,9 +34,14 @@ static struct dw_dma_platform_data mrfld_pdata = {
 	.multi_block = {1, 1, 1, 1, 1, 1, 1, 1},
 };
 
+static const struct dw_dma_pci_data idma32_pci_data = {
+	.pdata = &idma32_pdata,
+	.probe = idma32_dma_probe,
+};
+
 static int dw_pci_probe(struct pci_dev *pdev, const struct pci_device_id *pid)
 {
-	const struct dw_dma_platform_data *pdata = (void *)pid->driver_data;
+	const struct dw_dma_pci_data *data = (void *)pid->driver_data;
 	struct dw_dma_chip *chip;
 	int ret;
 
@@ -61,9 +74,9 @@ static int dw_pci_probe(struct pci_dev *pdev, const struct pci_device_id *pid)
 	chip->id = pdev->devfn;
 	chip->regs = pcim_iomap_table(pdev)[0];
 	chip->irq = pdev->irq;
-	chip->pdata = pdata;
+	chip->pdata = data->pdata;
 
-	ret = dw_dma_probe(chip);
+	ret = data->probe(chip);
 	if (ret)
 		return ret;
 
@@ -89,7 +102,7 @@ static int dw_pci_suspend_late(struct device *dev)
 	struct pci_dev *pci = to_pci_dev(dev);
 	struct dw_dma_chip *chip = pci_get_drvdata(pci);
 
-	return dw_dma_disable(chip);
+	return do_dw_dma_disable(chip);
 };
 
 static int dw_pci_resume_early(struct device *dev)
@@ -97,7 +110,7 @@ static int dw_pci_resume_early(struct device *dev)
 	struct pci_dev *pci = to_pci_dev(dev);
 	struct dw_dma_chip *chip = pci_get_drvdata(pci);
 
-	return dw_dma_enable(chip);
+	return do_dw_dma_enable(chip);
 };
 
 #endif /* CONFIG_PM_SLEEP */
@@ -108,24 +121,24 @@ static const struct dev_pm_ops dw_pci_dev_pm_ops = {
 
 static const struct pci_device_id dw_pci_id_table[] = {
 	/* Medfield (GPDMA) */
-	{ PCI_VDEVICE(INTEL, 0x0827) },
+	{ PCI_VDEVICE(INTEL, 0x0827), (kernel_ulong_t)&dw_pci_data },
 
 	/* BayTrail */
-	{ PCI_VDEVICE(INTEL, 0x0f06) },
-	{ PCI_VDEVICE(INTEL, 0x0f40) },
+	{ PCI_VDEVICE(INTEL, 0x0f06), (kernel_ulong_t)&dw_pci_data },
+	{ PCI_VDEVICE(INTEL, 0x0f40), (kernel_ulong_t)&dw_pci_data },
 
-	/* Merrifield iDMA 32-bit (GPDMA) */
-	{ PCI_VDEVICE(INTEL, 0x11a2), (kernel_ulong_t)&mrfld_pdata },
+	/* Merrifield */
+	{ PCI_VDEVICE(INTEL, 0x11a2), (kernel_ulong_t)&idma32_pci_data },
 
 	/* Braswell */
-	{ PCI_VDEVICE(INTEL, 0x2286) },
-	{ PCI_VDEVICE(INTEL, 0x22c0) },
+	{ PCI_VDEVICE(INTEL, 0x2286), (kernel_ulong_t)&dw_pci_data },
+	{ PCI_VDEVICE(INTEL, 0x22c0), (kernel_ulong_t)&dw_pci_data },
 
 	/* Haswell */
-	{ PCI_VDEVICE(INTEL, 0x9c60) },
+	{ PCI_VDEVICE(INTEL, 0x9c60), (kernel_ulong_t)&dw_pci_data },
 
 	/* Broadwell */
-	{ PCI_VDEVICE(INTEL, 0x9ce0) },
+	{ PCI_VDEVICE(INTEL, 0x9ce0), (kernel_ulong_t)&dw_pci_data },
 
 	{ }
 };
diff --git a/drivers/dma/dw/platform.c b/drivers/dma/dw/platform.c
index 58fc1ba02a1e..d5196c97e4f4 100644
--- a/drivers/dma/dw/platform.c
+++ b/drivers/dma/dw/platform.c
@@ -255,7 +255,7 @@ static void dw_shutdown(struct platform_device *pdev)
 	struct dw_dma_chip *chip = platform_get_drvdata(pdev);
 
 	/*
-	 * We have to call dw_dma_disable() to stop any ongoing transfer. On
+	 * We have to call do_dw_dma_disable() to stop any ongoing transfer. On
 	 * some platforms we can't do that since DMA device is powered off.
 	 * Moreover we have no possibility to check if the platform is affected
 	 * or not. That's why we call pm_runtime_get_sync() / pm_runtime_put()
@@ -264,7 +264,7 @@ static void dw_shutdown(struct platform_device *pdev)
 	 * used by the driver.
 	 */
 	pm_runtime_get_sync(chip->dev);
-	dw_dma_disable(chip);
+	do_dw_dma_disable(chip);
 	pm_runtime_put_sync_suspend(chip->dev);
 
 	clk_disable_unprepare(chip->clk);
@@ -294,7 +294,7 @@ static int dw_suspend_late(struct device *dev)
 {
 	struct dw_dma_chip *chip = dev_get_drvdata(dev);
 
-	dw_dma_disable(chip);
+	do_dw_dma_disable(chip);
 	clk_disable_unprepare(chip->clk);
 
 	return 0;
@@ -309,7 +309,7 @@ static int dw_resume_early(struct device *dev)
 	if (ret)
 		return ret;
 
-	return dw_dma_enable(chip);
+	return do_dw_dma_enable(chip);
 }
 
 #endif /* CONFIG_PM_SLEEP */
diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h
index 646c9c960c07..66aa8b227248 100644
--- a/drivers/dma/dw/regs.h
+++ b/drivers/dma/dw/regs.h
@@ -312,6 +312,19 @@ struct dw_dma {
 	u8			all_chan_mask;
 	u8			in_use;
 
+	/* Channel operations */
+	void	(*initialize_chan)(struct dw_dma_chan *dwc);
+	void	(*suspend_chan)(struct dw_dma_chan *dwc, bool drain);
+	void	(*encode_maxburst)(struct dw_dma_chan *dwc, u32 *maxburst);
+	u32	(*bytes2block)(struct dw_dma_chan *dwc, size_t bytes,
+			       unsigned int width, size_t *len);
+	size_t	(*block2bytes)(struct dw_dma_chan *dwc, u32 block, u32 width);
+
+	/* Device operations */
+	void (*set_device_name)(struct dw_dma *dw, int id);
+	void (*disable)(struct dw_dma *dw);
+	void (*enable)(struct dw_dma *dw);
+
 	/* platform data */
 	struct dw_dma_platform_data	*pdata;
 };