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Date:   Tue, 5 Oct 2021 18:25:34 +0530
From:   Akhil R <akhilrajeev@...dia.com>
To:     <jonathanh@...dia.com>
CC:     <akhilrajeev@...dia.com>, <dan.j.williams@...el.com>,
        <dmaengine@...r.kernel.org>, <kyarlagadda@...dia.com>,
        <ldewangan@...dia.com>, <linux-kernel@...r.kernel.org>,
        <linux-tegra@...r.kernel.org>, <p.zabel@...gutronix.de>,
        <rgumasta@...dia.com>, <thierry.reding@...il.com>,
        <vkoul@...nel.org>, "Pavan Kunapuli" <pkunapuli@...dia.com>
Subject: [PATCH v9 2/4] dmaengine: tegra: Add tegra gpcdma driver

Adding GPC DMA controller driver for Tegra186 and Tegra194. The driver
supports dma transfers between memory to memory, IO peripheral to memory
and memory to IO peripheral.

Signed-off-by: Pavan Kunapuli <pkunapuli@...dia.com>
Signed-off-by: Rajesh Gumasta <rgumasta@...dia.com>
Signed-off-by: Akhil R <akhilrajeev@...dia.com>
Reviewed-by: Jon Hunter <jonathanh@...dia.com>
---
 drivers/dma/Kconfig            |   12 +
 drivers/dma/Makefile           |    1 +
 drivers/dma/tegra186-gpc-dma.c | 1297 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1310 insertions(+)
 create mode 100644 drivers/dma/tegra186-gpc-dma.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 80c2c03..2eb9062 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -654,6 +654,18 @@ config TEGRA210_ADMA
 	  peripheral and vice versa. It does not support memory to
 	  memory data transfer.
 
+config TEGRA186_GPC_DMA
+	tristate "NVIDIA Tegra GPC DMA support"
+	depends on ARCH_TEGRA_186_SOC || ARCH_TEGRA_194_SOC || COMPILE_TEST
+	select DMA_ENGINE
+	help
+	  Support for the NVIDIA Tegra186 and Tegra194 GPC DMA controller
+	  driver. The DMA controller has multiple DMA channels which can
+	  be configured for different peripherals like UART, SPI, etc
+	  which are on APB bus.
+	  This DMA controller transfers data from memory to peripheral FIFO
+	  or vice versa. It also supports memory to memory data transfer.
+
 config TIMB_DMA
 	tristate "Timberdale FPGA DMA support"
 	depends on MFD_TIMBERDALE || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 616d926..b701006 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_S3C24XX_DMAC) += s3c24xx-dma.o
 obj-$(CONFIG_TXX9_DMAC) += txx9dmac.o
 obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
 obj-$(CONFIG_TEGRA210_ADMA) += tegra210-adma.o
+obj-$(CONFIG_TEGRA186_GPC_DMA) += tegra186-gpc-dma.o
 obj-$(CONFIG_TIMB_DMA) += timb_dma.o
 obj-$(CONFIG_UNIPHIER_MDMAC) += uniphier-mdmac.o
 obj-$(CONFIG_UNIPHIER_XDMAC) += uniphier-xdmac.o
diff --git a/drivers/dma/tegra186-gpc-dma.c b/drivers/dma/tegra186-gpc-dma.c
new file mode 100644
index 0000000..d21aa07
--- /dev/null
+++ b/drivers/dma/tegra186-gpc-dma.c
@@ -0,0 +-2,1294 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DMA driver for NVIDIA Tegra186 and Tegra194 GPC DMA controller.
+ *
+ * Copyright (c) 2014-2021, NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#include <linux/bitops.h>
+#include <linux/bitfield.h>
+#include <linux/minmax.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/iommu.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/version.h>
+#include <dt-bindings/memory/tegra186-mc.h>
+#include "virt-dma.h"
+
+/* CSR register */
+#define TEGRA_GPCDMA_CHAN_CSR			0x00
+#define TEGRA_GPCDMA_CSR_ENB			BIT(31)
+#define TEGRA_GPCDMA_CSR_IE_EOC			BIT(30)
+#define TEGRA_GPCDMA_CSR_ONCE			BIT(27)
+
+#define TEGRA_GPCDMA_CSR_FC_MODE		GENMASK(25, 24)
+#define TEGRA_GPCDMA_CSR_FC_MODE_NO_MMIO	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_FC_MODE, 0)
+#define TEGRA_GPCDMA_CSR_FC_MODE_ONE_MMIO	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_FC_MODE, 1)
+#define TEGRA_GPCDMA_CSR_FC_MODE_TWO_MMIO	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_FC_MODE, 2)
+#define TEGRA_GPCDMA_CSR_FC_MODE_FOUR_MMIO	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_FC_MODE, 3)
+
+#define TEGRA_GPCDMA_CSR_DMA			GENMASK(23, 21)
+#define TEGRA_GPCDMA_CSR_DMA_IO2MEM_NO_FC	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 0)
+#define TEGRA_GPCDMA_CSR_DMA_IO2MEM_FC		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 1)
+#define TEGRA_GPCDMA_CSR_DMA_MEM2IO_NO_FC	\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 2)
+#define TEGRA_GPCDMA_CSR_DMA_MEM2IO_FC		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 3)
+#define TEGRA_GPCDMA_CSR_DMA_MEM2MEM		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 4)
+#define TEGRA_GPCDMA_CSR_DMA_FIXED_PAT		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_DMA, 6)
+
+#define TEGRA_GPCDMA_CSR_REQ_SEL_MASK		GENMASK(20, 16)
+#define TEGRA_GPCDMA_CSR_REQ_SEL_UNUSED		\
+					FIELD_PREP(TEGRA_GPCDMA_CSR_REQ_SEL_MASK, 4)
+#define TEGRA_GPCDMA_CSR_IRQ_MASK			BIT(15)
+#define TEGRA_GPCDMA_CSR_WEIGHT				GENMASK(13, 10)
+
+/* STATUS register */
+#define TEGRA_GPCDMA_CHAN_STATUS			0x004
+#define TEGRA_GPCDMA_STATUS_BUSY			BIT(31)
+#define TEGRA_GPCDMA_STATUS_ISE_EOC			BIT(30)
+#define TEGRA_GPCDMA_STATUS_PING_PONG		BIT(28)
+#define TEGRA_GPCDMA_STATUS_DMA_ACTIVITY	BIT(27)
+#define TEGRA_GPCDMA_STATUS_CHANNEL_PAUSE	BIT(26)
+#define TEGRA_GPCDMA_STATUS_CHANNEL_RX		BIT(25)
+#define TEGRA_GPCDMA_STATUS_CHANNEL_TX		BIT(24)
+#define TEGRA_GPCDMA_STATUS_IRQ_INTR_STA	BIT(23)
+#define TEGRA_GPCDMA_STATUS_IRQ_STA			BIT(21)
+#define TEGRA_GPCDMA_STATUS_IRQ_TRIG_STA	BIT(20)
+
+#define TEGRA_GPCDMA_CHAN_CSRE				0x008
+#define TEGRA_GPCDMA_CHAN_CSRE_PAUSE		BIT(31)
+
+/* Source address */
+#define TEGRA_GPCDMA_CHAN_SRC_PTR			0x00C
+
+/* Destination address */
+#define TEGRA_GPCDMA_CHAN_DST_PTR			0x010
+
+/* High address pointer */
+#define TEGRA_GPCDMA_CHAN_HIGH_ADDR_PTR		0x014
+#define TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR		GENMASK(7, 0)
+#define TEGRA_GPCDMA_HIGH_ADDR_DST_PTR		GENMASK(23, 16)
+
+/* MC sequence register */
+#define TEGRA_GPCDMA_CHAN_MCSEQ			0x18
+#define TEGRA_GPCDMA_MCSEQ_DATA_SWAP	BIT(31)
+#define TEGRA_GPCDMA_MCSEQ_REQ_COUNT	GENMASK(30, 25)
+#define TEGRA_GPCDMA_MCSEQ_BURST		GENMASK(24, 23)
+#define TEGRA_GPCDMA_MCSEQ_BURST_2		\
+					FIELD_PREP(TEGRA_GPCDMA_MCSEQ_BURST, 0)
+#define TEGRA_GPCDMA_MCSEQ_BURST_16		\
+					FIELD_PREP(TEGRA_GPCDMA_MCSEQ_BURST, 3)
+#define TEGRA_GPCDMA_MCSEQ_WRAP1		GENMASK(22, 20)
+#define TEGRA_GPCDMA_MCSEQ_WRAP0		GENMASK(19, 17)
+#define TEGRA_GPCDMA_MCSEQ_WRAP_NONE		0
+
+#define TEGRA_GPCDMA_MCSEQ_STREAM_ID1_MASK	GENMASK(13, 7)
+#define TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK	GENMASK(6, 0)
+
+/* MMIO sequence register */
+#define TEGRA_GPCDMA_CHAN_MMIOSEQ			0x01c
+#define TEGRA_GPCDMA_MMIOSEQ_DBL_BUF		BIT(31)
+#define TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH		GENMASK(30, 28)
+#define TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_8	\
+					FIELD_PREP(TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH, 0)
+#define TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_16	\
+					FIELD_PREP(TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH, 1)
+#define TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_32	\
+					FIELD_PREP(TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH, 2)
+#define TEGRA_GPCDMA_MMIOSEQ_DATA_SWAP		BIT(27)
+#define TEGRA_GPCDMA_MMIOSEQ_BURST			GENMASK(26, 23)
+#define TEGRA_GPCDMA_MMIOSEQ_BURST_SHIFT	23
+#define TEGRA_GPCDMA_MMIOSEQ_BURST_MIN		1
+#define TEGRA_GPCDMA_MMIOSEQ_BURST_MAX		16
+#define TEGRA_GPCDMA_MMIOSEQ_MASTER_ID		GENMASK(22, 19)
+#define TEGRA_GPCDMA_MMIOSEQ_WRAP_WORD		GENMASK(18, 16)
+#define TEGRA_GPCDMA_MMIOSEQ_MMIO_PROT		GENMASK(8, 7)
+
+/* Channel WCOUNT */
+#define TEGRA_GPCDMA_CHAN_WCOUNT		0x20
+
+/* Transfer count */
+#define TEGRA_GPCDMA_CHAN_XFER_COUNT		0x24
+
+/* DMA byte count status */
+#define TEGRA_GPCDMA_CHAN_DMA_BYTE_STATUS	0x28
+
+/* Error Status Register */
+#define TEGRA_GPCDMA_CHAN_ERR_STATUS		0x30
+#define TEGRA_GPCDMA_CHAN_ERR_TYPE_SHIFT	(8)
+#define TEGRA_GPCDMA_CHAN_ERR_TYPE_MASK	(0xF)
+#define TEGRA_GPCDMA_CHAN_ERR_TYPE(err)	(			\
+		((err) >> TEGRA_GPCDMA_CHAN_ERR_TYPE_SHIFT) &	\
+		TEGRA_GPCDMA_CHAN_ERR_TYPE_MASK)
+#define TEGRA_DMA_BM_FIFO_FULL_ERR		(0xF)
+#define TEGRA_DMA_PERIPH_FIFO_FULL_ERR		(0xE)
+#define TEGRA_DMA_PERIPH_ID_ERR			(0xD)
+#define TEGRA_DMA_STREAM_ID_ERR			(0xC)
+#define TEGRA_DMA_MC_SLAVE_ERR			(0xB)
+#define TEGRA_DMA_MMIO_SLAVE_ERR		(0xA)
+
+/* Fixed Pattern */
+#define TEGRA_GPCDMA_CHAN_FIXED_PATTERN		0x34
+
+#define TEGRA_GPCDMA_CHAN_TZ			0x38
+#define TEGRA_GPCDMA_CHAN_TZ_MMIO_PROT_1	BIT(0)
+#define TEGRA_GPCDMA_CHAN_TZ_MC_PROT_1		BIT(1)
+
+#define TEGRA_GPCDMA_CHAN_SPARE			0x3c
+#define TEGRA_GPCDMA_CHAN_SPARE_EN_LEGACY_FC	BIT(16)
+
+/*
+ * If any burst is in flight and DMA paused then this is the time to complete
+ * on-flight burst and update DMA status register.
+ */
+#define TEGRA_GPCDMA_BURST_COMPLETE_TIME	20
+#define TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT	100
+
+/* Channel base address offset from GPCDMA base address */
+#define TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET	0x10000
+
+struct tegra_dma;
+
+/*
+ * tegra_dma_chip_data Tegra chip specific DMA data
+ * @nr_channels: Number of channels available in the controller.
+ * @channel_reg_size: Channel register size.
+ * @max_dma_count: Maximum DMA transfer count supported by DMA controller.
+ * @hw_support_pause: DMA HW engine support pause of the channel.
+ */
+struct tegra_dma_chip_data {
+	unsigned int nr_channels;
+	unsigned int channel_reg_size;
+	unsigned int max_dma_count;
+	bool hw_support_pause;
+};
+
+/* DMA channel registers */
+struct tegra_dma_channel_regs {
+	unsigned long csr;
+	unsigned long src_ptr;
+	unsigned long dst_ptr;
+	unsigned long high_addr_ptr;
+	unsigned long mc_seq;
+	unsigned long mmio_seq;
+	unsigned long wcount;
+	unsigned long fixed_pattern;
+};
+
+/*
+ * tegra_dma_desc: Tegra DMA descriptors which uses virt_dma_desc to
+ * manage client request and keep track of transfer status, callbacks
+ * and request counts etc.
+ */
+struct tegra_dma_desc {
+	struct virt_dma_desc vd;
+	int bytes_requested;
+	int bytes_transferred;
+	struct tegra_dma_channel *tdc;
+	struct tegra_dma_channel_regs ch_regs;
+};
+
+struct tegra_dma_channel;
+
+/*
+ * tegra_dma_channel: Channel specific information
+ */
+struct tegra_dma_channel {
+	struct virt_dma_chan vc;
+	struct tegra_dma_desc *dma_desc;
+	char name[30];
+	bool config_init;
+	int id;
+	int irq;
+	unsigned int stream_id;
+	unsigned long chan_base_offset;
+	raw_spinlock_t lock;
+	bool busy;
+	struct tegra_dma *tdma;
+	int slave_id;
+	enum dma_transfer_direction sid_dir;
+	struct dma_slave_config dma_sconfig;
+};
+
+/*
+ * tegra_dma: Tegra DMA specific information
+ */
+struct tegra_dma {
+	struct dma_device dma_dev;
+	struct device *dev;
+	void __iomem *base_addr;
+	const struct tegra_dma_chip_data *chip_data;
+	struct reset_control *rst;
+	unsigned long sid_m2d_reserved;
+	unsigned long sid_d2m_reserved;
+	unsigned long sid_m2m_reserved;
+	struct tegra_dma_channel channels[0];
+};
+
+static inline void tdc_write(struct tegra_dma_channel *tdc,
+			     u32 reg, u32 val)
+{
+	writel_relaxed(val, tdc->tdma->base_addr + tdc->chan_base_offset + reg);
+}
+
+static inline u32 tdc_read(struct tegra_dma_channel *tdc, u32 reg)
+{
+	return readl_relaxed(tdc->tdma->base_addr + tdc->chan_base_offset + reg);
+}
+
+static inline struct tegra_dma_channel *to_tegra_dma_chan(struct dma_chan *dc)
+{
+	return container_of(dc, struct tegra_dma_channel, vc.chan);
+}
+
+static inline struct tegra_dma_desc *vd_to_tegra_dma_desc(struct virt_dma_desc *vd)
+{
+	return container_of(vd, struct tegra_dma_desc, vd);
+}
+
+static inline struct device *tdc2dev(struct tegra_dma_channel *tdc)
+{
+	return tdc->vc.chan.device->dev;
+}
+
+static void tegra_dma_dump_chan_regs(struct tegra_dma_channel *tdc)
+{
+	dev_dbg(tdc2dev(tdc), "DMA Channel %d name %s register dump:\n",
+		tdc->id, tdc->name);
+	dev_dbg(tdc2dev(tdc), "CSR %x STA %x CSRE %x SRC %x DST %x\n",
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSR),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSRE),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_SRC_PTR),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_DST_PTR)
+	);
+	dev_dbg(tdc2dev(tdc), "MCSEQ %x IOSEQ %x WCNT %x XFER %x BSTA %x\n",
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_MMIOSEQ),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_WCOUNT),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_XFER_COUNT),
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_DMA_BYTE_STATUS)
+	);
+	dev_dbg(tdc2dev(tdc), "DMA ERR_STA %x\n",
+		tdc_read(tdc, TEGRA_GPCDMA_CHAN_ERR_STATUS));
+}
+
+static int tegra_dma_sid_reserve(struct tegra_dma_channel *tdc,
+				 enum dma_transfer_direction direction)
+{
+	struct tegra_dma *tdma = tdc->tdma;
+	unsigned int sid = tdc->slave_id;
+
+	if (!is_slave_direction(direction))
+		return 0;
+
+	switch (direction) {
+	case DMA_MEM_TO_DEV:
+		if (test_and_set_bit(sid, &tdma->sid_m2d_reserved)) {
+			dev_err(tdma->dev, "slave id already in use\n");
+			return -EINVAL;
+		}
+		break;
+	case DMA_DEV_TO_MEM:
+		if (test_and_set_bit(sid, &tdma->sid_d2m_reserved)) {
+			dev_err(tdma->dev, "slave id already in use\n");
+			return -EINVAL;
+		}
+		break;
+	}
+
+	tdc->sid_dir = direction;
+
+	return 0;
+}
+
+static void tegra_dma_sid_free(struct tegra_dma_channel *tdc)
+{
+	struct tegra_dma *tdma = tdc->tdma;
+	unsigned int sid = tdc->slave_id;
+
+	switch (tdc->sid_dir) {
+	case DMA_MEM_TO_DEV:
+		clear_bit(sid,  &tdma->sid_m2d_reserved);
+		break;
+	case DMA_DEV_TO_MEM:
+		clear_bit(sid,  &tdma->sid_d2m_reserved);
+		break;
+	}
+
+	tdc->sid_dir = DMA_TRANS_NONE;
+}
+
+static void tegra_dma_desc_free(struct virt_dma_desc *vd)
+{
+	kfree(container_of(vd, struct tegra_dma_desc, vd));
+}
+
+static int tegra_dma_slave_config(struct dma_chan *dc,
+				  struct dma_slave_config *sconfig)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+
+	if (tdc->dma_desc) {
+		dev_err(tdc2dev(tdc), "Configuration not allowed\n");
+		return -EBUSY;
+	}
+
+	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
+	tdc->config_init = true;
+
+	return 0;
+}
+
+static int tegra_dma_pause(struct tegra_dma_channel *tdc)
+{
+	u32 val;
+	int ret;
+
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, TEGRA_GPCDMA_CHAN_CSRE_PAUSE);
+
+	/* Wait until busy bit is de-asserted */
+	ret = readl_relaxed_poll_timeout_atomic(tdc->tdma->base_addr +
+			tdc->chan_base_offset + TEGRA_GPCDMA_CHAN_STATUS,
+			val,
+			!(val & TEGRA_GPCDMA_STATUS_BUSY),
+			TEGRA_GPCDMA_BURST_COMPLETE_TIME,
+			TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT);
+
+	if (ret)
+		dev_err(tdc2dev(tdc), "DMA pause timed out\n");
+
+	return ret;
+}
+
+static void tegra_dma_stop(struct tegra_dma_channel *tdc)
+{
+	u32 csr, status;
+
+	csr = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSR);
+
+	/* Disable interrupts */
+	csr &= ~TEGRA_GPCDMA_CSR_IE_EOC;
+
+	/* Disable DMA */
+	csr &= ~TEGRA_GPCDMA_CSR_ENB;
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, csr);
+
+	/* Clear interrupt status if it is there */
+	status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS);
+	if (status & TEGRA_GPCDMA_STATUS_ISE_EOC) {
+		dev_dbg(tdc2dev(tdc), "%s():clearing interrupt\n", __func__);
+		tdc_write(tdc, TEGRA_GPCDMA_CHAN_STATUS, status);
+	}
+	tdc->busy = false;
+}
+
+static void tegra_dma_start(struct tegra_dma_channel *tdc)
+{
+	struct tegra_dma_channel_regs *ch_regs;
+	struct virt_dma_desc *vdesc;
+
+	if (tdc->busy)
+		return;
+
+	vdesc = vchan_next_desc(&tdc->vc);
+	if (!vdesc)
+		return;
+
+	tdc->dma_desc = vd_to_tegra_dma_desc(vdesc);
+	list_del(&vdesc->node);
+
+	tdc->dma_desc->tdc = tdc;
+	ch_regs = &tdc->dma_desc->ch_regs;
+
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_WCOUNT, ch_regs->wcount);
+
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, 0);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_SRC_PTR, ch_regs->src_ptr);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_DST_PTR, ch_regs->dst_ptr);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_HIGH_ADDR_PTR, ch_regs->high_addr_ptr);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_FIXED_PATTERN, ch_regs->fixed_pattern);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_MMIOSEQ, ch_regs->mmio_seq);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_MCSEQ, ch_regs->mc_seq);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSRE, 0);
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, ch_regs->csr);
+
+	/* Start DMA */
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR,
+		  ch_regs->csr | TEGRA_GPCDMA_CSR_ENB);
+
+	tdc->busy = true;
+}
+
+static void tegra_dma_xfer_complete(struct tegra_dma_channel *tdc)
+{
+	struct tegra_dma_desc *dma_desc;
+
+	tdc->busy = false;
+	dma_desc = tdc->dma_desc;
+	dma_desc->bytes_transferred += dma_desc->bytes_requested;
+
+	vchan_cookie_complete(&tdc->dma_desc->vd);
+}
+
+static void tegra_dma_chan_decode_error(struct tegra_dma_channel *tdc,
+					unsigned int err_status)
+{
+	switch (TEGRA_GPCDMA_CHAN_ERR_TYPE(err_status)) {
+	case TEGRA_DMA_BM_FIFO_FULL_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d bm fifo full\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_PERIPH_FIFO_FULL_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d peripheral fifo full\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_PERIPH_ID_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d illegal peripheral id\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_STREAM_ID_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d illegal stream id\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_MC_SLAVE_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d mc slave error\n", tdc->id);
+		break;
+
+	case TEGRA_DMA_MMIO_SLAVE_ERR:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d mmio slave error\n", tdc->id);
+		break;
+
+	default:
+		dev_err(tdc->tdma->dev,
+			"GPCDMA CH%d security violation %x\n", tdc->id,
+			err_status);
+	}
+}
+
+static irqreturn_t tegra_dma_isr(int irq, void *dev_id)
+{
+	struct tegra_dma_channel *tdc = dev_id;
+	irqreturn_t ret = IRQ_NONE;
+	u32 status;
+
+	raw_spin_lock(&tdc->lock);
+
+	/* Check channel error status register */
+	status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_ERR_STATUS);
+	if (status) {
+		tegra_dma_chan_decode_error(tdc, status);
+		tegra_dma_dump_chan_regs(tdc);
+		tdc_write(tdc, TEGRA_GPCDMA_CHAN_ERR_STATUS, 0xFFFFFFFF);
+	}
+
+	status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS);
+	if (status & TEGRA_GPCDMA_STATUS_ISE_EOC) {
+		tdc_write(tdc, TEGRA_GPCDMA_CHAN_STATUS,
+			  TEGRA_GPCDMA_STATUS_ISE_EOC);
+
+		tegra_dma_xfer_complete(tdc);
+		tegra_dma_start(tdc);
+
+		ret = IRQ_HANDLED;
+	}
+
+	raw_spin_unlock(&tdc->lock);
+	return ret;
+}
+
+static void tegra_dma_issue_pending(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&tdc->lock, flags);
+
+	if (!tdc->busy)
+		if (vchan_issue_pending(&tdc->vc))
+			tegra_dma_start(tdc);
+
+	raw_spin_unlock_irqrestore(&tdc->lock, flags);
+}
+
+static void tegra_dma_reset_client(struct tegra_dma_channel *tdc)
+{
+	u32 csr = tdc_read(tdc, TEGRA_GPCDMA_CHAN_CSR);
+
+	csr &= ~(TEGRA_GPCDMA_CSR_REQ_SEL_MASK);
+	csr |= TEGRA_GPCDMA_CSR_REQ_SEL_UNUSED;
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_CSR, csr);
+}
+
+static int tegra_dma_stop_client(struct tegra_dma_channel *tdc)
+{
+	int ret;
+	unsigned long status;
+
+	/* Before Reading DMA status to figure out number
+	 * of bytes transferred by DMA channel:
+	 * Change the client associated with the DMA channel
+	 * to stop DMA engine from starting any more bursts for
+	 * the given client and wait for in flight bursts to complete
+	 */
+	tegra_dma_reset_client(tdc);
+
+	/* Wait for in flight data transfer to finish */
+	udelay(TEGRA_GPCDMA_BURST_COMPLETE_TIME);
+
+	/* If TX/RX path is still active wait till it becomes
+	 * inactive
+	 */
+
+	ret = readl_relaxed_poll_timeout_atomic(tdc->tdma->base_addr +
+				tdc->chan_base_offset +
+				TEGRA_GPCDMA_CHAN_STATUS,
+				status,
+				!(status & (TEGRA_GPCDMA_STATUS_CHANNEL_TX |
+				TEGRA_GPCDMA_STATUS_CHANNEL_RX)),
+				5,
+				TEGRA_GPCDMA_BURST_COMPLETION_TIMEOUT);
+	if (ret) {
+		dev_err(tdc2dev(tdc), "Timeout waiting for DMA burst completion!\n");
+		tegra_dma_dump_chan_regs(tdc);
+	}
+
+	return ret;
+}
+
+static int tegra_dma_terminate_all(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned long wcount = 0;
+	unsigned long status;
+	unsigned long flags;
+	int err;
+
+	raw_spin_lock_irqsave(&tdc->lock, flags);
+
+	if (!tdc->dma_desc) {
+		raw_spin_unlock_irqrestore(&tdc->lock, flags);
+		return 0;
+	}
+
+	if (!tdc->busy)
+		goto skip_dma_stop;
+
+	if (tdc->tdma->chip_data->hw_support_pause)
+		err = tegra_dma_pause(tdc);
+	else
+		err = tegra_dma_stop_client(tdc);
+
+	if (err) {
+		raw_spin_unlock_irqrestore(&tdc->lock, flags);
+		return err;
+	}
+
+	status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS);
+	if (status & TEGRA_GPCDMA_STATUS_ISE_EOC) {
+		dev_dbg(tdc2dev(tdc), "%s():handling isr\n", __func__);
+		tegra_dma_xfer_complete(tdc);
+		status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS);
+	}
+
+	wcount = tdc_read(tdc, TEGRA_GPCDMA_CHAN_XFER_COUNT);
+	tegra_dma_stop(tdc);
+
+	tdc->dma_desc->bytes_transferred +=
+			tdc->dma_desc->bytes_requested - (wcount * 4);
+
+skip_dma_stop:
+	tegra_dma_sid_free(tdc);
+	kfree(tdc->dma_desc);
+	vchan_free_chan_resources(&tdc->vc);
+
+	raw_spin_unlock_irqrestore(&tdc->lock, flags);
+	return 0;
+}
+
+static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *txstate)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	struct tegra_dma_desc *dma_desc = NULL;
+	struct virt_dma_desc *vd;
+	unsigned int residual;
+	enum dma_status ret;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&tdc->lock, flags);
+
+	ret = dma_cookie_status(dc, cookie, txstate);
+	if (ret == DMA_COMPLETE) {
+		raw_spin_unlock_irqrestore(&tdc->lock, flags);
+		return ret;
+	}
+
+	vd = vchan_find_desc(&tdc->vc, cookie);
+	if (vd) {
+		dma_desc = vd_to_tegra_dma_desc(vd);
+		residual = dma_desc->bytes_requested;
+		dma_set_residue(txstate, residual);
+	} else if (tdc->dma_desc && tdc->dma_desc->vd.tx.cookie == cookie) {
+		dma_desc = tdc->dma_desc;
+		residual =  dma_desc->bytes_requested -
+					(dma_desc->bytes_transferred %
+					dma_desc->bytes_requested);
+		dma_set_residue(txstate, residual);
+	} else {
+		dev_err(tdc2dev(tdc), "cookie %d is not found\n", cookie);
+	}
+
+	raw_spin_unlock_irqrestore(&tdc->lock, flags);
+	return ret;
+}
+
+static inline int get_bus_width(struct tegra_dma_channel *tdc,
+				enum dma_slave_buswidth slave_bw)
+{
+	switch (slave_bw) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		return TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_8;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		return TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_16;
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		return TEGRA_GPCDMA_MMIOSEQ_BUS_WIDTH_32;
+	default:
+		dev_err(tdc2dev(tdc), "given slave bus width is not supported\n");
+		return -EINVAL;
+	}
+}
+
+static unsigned int get_burst_size(struct tegra_dma_channel *tdc,
+				   u32 burst_size, enum dma_slave_buswidth slave_bw,
+				   int len)
+{
+	unsigned int burst_mmio_width, burst_byte;
+
+	/*
+	 * burst_size from client is in terms of the bus_width.
+	 * convert that into words.
+	 * If burst_size is not specified from client, then use
+	 * len to calculate the optimum burst size
+	 */
+	burst_byte = burst_size ? burst_size * slave_bw : len;
+	burst_mmio_width = burst_byte / 4;
+
+	clamp(burst_mmio_width, TEGRA_GPCDMA_MMIOSEQ_BURST_MIN,
+	      TEGRA_GPCDMA_MMIOSEQ_BURST_MAX);
+
+	return (fls(burst_mmio_width) - 1) << TEGRA_GPCDMA_MMIOSEQ_BURST_SHIFT;
+}
+
+static int get_transfer_param(struct tegra_dma_channel *tdc,
+			      enum dma_transfer_direction direction,
+			      unsigned long *apb_addr,
+			      unsigned long *mmio_seq,
+			      unsigned long *csr,
+			      unsigned int *burst_size,
+			      enum dma_slave_buswidth *slave_bw)
+{
+	switch (direction) {
+	case DMA_MEM_TO_DEV:
+		*apb_addr = tdc->dma_sconfig.dst_addr;
+		*mmio_seq = get_bus_width(tdc, tdc->dma_sconfig.dst_addr_width);
+		*burst_size = tdc->dma_sconfig.dst_maxburst;
+		*slave_bw = tdc->dma_sconfig.dst_addr_width;
+		*csr = TEGRA_GPCDMA_CSR_DMA_MEM2IO_FC;
+		return 0;
+	case DMA_DEV_TO_MEM:
+		*apb_addr = tdc->dma_sconfig.src_addr;
+		*mmio_seq = get_bus_width(tdc, tdc->dma_sconfig.src_addr_width);
+		*burst_size = tdc->dma_sconfig.src_maxburst;
+		*slave_bw = tdc->dma_sconfig.src_addr_width;
+		*csr = TEGRA_GPCDMA_CSR_DMA_IO2MEM_FC;
+		return 0;
+	case DMA_MEM_TO_MEM:
+		*burst_size = tdc->dma_sconfig.src_addr_width;
+		*csr = TEGRA_GPCDMA_CSR_DMA_MEM2MEM;
+		return 0;
+	default:
+		dev_err(tdc2dev(tdc), "DMA direction is not supported\n");
+	}
+
+	return -EINVAL;
+}
+
+static struct dma_async_tx_descriptor *
+tegra_dma_prep_dma_memset(struct dma_chan *dc, dma_addr_t dest, int value,
+			  size_t len, unsigned long flags)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned int max_dma_count = tdc->tdma->chip_data->max_dma_count;
+	struct tegra_dma_desc *dma_desc;
+	unsigned long csr, mc_seq;
+
+	if ((len & 3) || (dest & 3) || len > max_dma_count) {
+		dev_err(tdc2dev(tdc),
+			"DMA length/memory address is not supported\n");
+		return NULL;
+	}
+
+	/* Set dma mode to fixed pattern */
+	csr = TEGRA_GPCDMA_CSR_DMA_FIXED_PAT;
+	/* Enable once or continuous mode */
+	csr |= TEGRA_GPCDMA_CSR_ONCE;
+	/* Enable IRQ mask */
+	csr |= TEGRA_GPCDMA_CSR_IRQ_MASK;
+	/* Enable the dma interrupt */
+	if (flags & DMA_PREP_INTERRUPT)
+		csr |= TEGRA_GPCDMA_CSR_IE_EOC;
+	/* Configure default priority weight for the channel */
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_WEIGHT, 1);
+
+	mc_seq =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
+	/* retain stream-id and clean rest */
+	mc_seq &= TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK;
+
+	/* Set the address wrapping */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP0,
+						TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP1,
+						TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+
+	/* Program outstanding MC requests */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_REQ_COUNT, 1);
+	/* Set burst size */
+	mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_16;
+
+	dma_desc = kzalloc(sizeof(*dma_desc), GFP_NOWAIT);
+	if (!dma_desc)
+		return NULL;
+
+	dma_desc->bytes_requested = 0;
+	dma_desc->bytes_transferred = 0;
+
+	dma_desc->bytes_requested += len;
+	dma_desc->ch_regs.src_ptr = 0;
+	dma_desc->ch_regs.dst_ptr = dest;
+	dma_desc->ch_regs.high_addr_ptr =
+			FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
+	dma_desc->ch_regs.fixed_pattern = value;
+	/* Word count reg takes value as (N +1) words */
+	dma_desc->ch_regs.wcount = ((len - 4) >> 2);
+	dma_desc->ch_regs.csr = csr;
+	dma_desc->ch_regs.mmio_seq = 0;
+	dma_desc->ch_regs.mc_seq = mc_seq;
+
+	tdc->dma_desc = dma_desc;
+
+	return vchan_tx_prep(&tdc->vc, &dma_desc->vd, flags);
+}
+
+static struct dma_async_tx_descriptor *
+tegra_dma_prep_dma_memcpy(struct dma_chan *dc, dma_addr_t dest,
+			  dma_addr_t src, size_t len, unsigned long flags)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned int max_dma_count = tdc->tdma->chip_data->max_dma_count;
+	struct tegra_dma_desc *dma_desc;
+	unsigned long csr, mc_seq;
+
+	if ((len & 3) || (src & 3) || (dest & 3) || len > max_dma_count) {
+		dev_err(tdc2dev(tdc),
+			"DMA length/memory address is not supported\n");
+		return NULL;
+	}
+
+	/* Set dma mode to memory to memory transfer */
+	csr = TEGRA_GPCDMA_CSR_DMA_MEM2MEM;
+	/* Enable once or continuous mode */
+	csr |= TEGRA_GPCDMA_CSR_ONCE;
+	/* Enable IRQ mask */
+	csr |= TEGRA_GPCDMA_CSR_IRQ_MASK;
+	/* Enable the dma interrupt */
+	if (flags & DMA_PREP_INTERRUPT)
+		csr |= TEGRA_GPCDMA_CSR_IE_EOC;
+	/* Configure default priority weight for the channel */
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_WEIGHT, 1);
+
+	mc_seq =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
+	/* retain stream-id and clean rest */
+	mc_seq &= (TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK) |
+				(TEGRA_GPCDMA_MCSEQ_STREAM_ID1_MASK);
+
+	/* Set the address wrapping */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP0,
+						TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP1,
+						TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+
+	/* Program outstanding MC requests */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_REQ_COUNT, 1);
+	/* Set burst size */
+	mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_16;
+
+	dma_desc = kzalloc(sizeof(*dma_desc), GFP_NOWAIT);
+	if (!dma_desc)
+		return NULL;
+
+	dma_desc->bytes_requested = 0;
+	dma_desc->bytes_transferred = 0;
+
+	dma_desc->bytes_requested += len;
+	dma_desc->ch_regs.src_ptr = src;
+	dma_desc->ch_regs.dst_ptr = dest;
+	dma_desc->ch_regs.high_addr_ptr =
+		FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (src >> 32));
+	dma_desc->ch_regs.high_addr_ptr |=
+		FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (dest >> 32));
+	/* Word count reg takes value as (N +1) words */
+	dma_desc->ch_regs.wcount = ((len - 4) >> 2);
+	dma_desc->ch_regs.csr = csr;
+	dma_desc->ch_regs.mmio_seq = 0;
+	dma_desc->ch_regs.mc_seq = mc_seq;
+
+	return vchan_tx_prep(&tdc->vc, &dma_desc->vd, flags);
+}
+
+static struct dma_async_tx_descriptor *
+tegra_dma_prep_slave_sg(struct dma_chan *dc, struct scatterlist *sgl,
+			unsigned int sg_len, enum dma_transfer_direction direction,
+			unsigned long flags, void *context)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned long csr, mc_seq, apb_ptr = 0, mmio_seq = 0;
+	enum dma_slave_buswidth slave_bw;
+	struct tegra_dma_desc *dma_desc;
+	struct scatterlist *sg;
+	u32 burst_size;
+	unsigned int i;
+	int ret;
+
+	if (!tdc->config_init) {
+		dev_err(tdc2dev(tdc), "DMA channel is not configured\n");
+		return NULL;
+	}
+	if (sg_len < 1) {
+		dev_err(tdc2dev(tdc), "Invalid segment length %d\n", sg_len);
+		return NULL;
+	}
+
+	ret = tegra_dma_sid_reserve(tdc, direction);
+	if (ret)
+		return NULL;
+
+	ret = get_transfer_param(tdc, direction, &apb_ptr, &mmio_seq, &csr,
+				 &burst_size, &slave_bw);
+	if (ret < 0)
+		return NULL;
+
+	/* Enable once or continuous mode */
+	csr |= TEGRA_GPCDMA_CSR_ONCE;
+	/* Program the slave id in requestor select */
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_REQ_SEL_MASK, tdc->slave_id);
+	/* Enable IRQ mask */
+	csr |= TEGRA_GPCDMA_CSR_IRQ_MASK;
+	/* Configure default priority weight for the channel*/
+	csr |= FIELD_PREP(TEGRA_GPCDMA_CSR_WEIGHT, 1);
+
+	/* Enable the dma interrupt */
+	if (flags & DMA_PREP_INTERRUPT)
+		csr |= TEGRA_GPCDMA_CSR_IE_EOC;
+
+	mc_seq =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
+	/* retain stream-id and clean rest */
+	mc_seq &= TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK;
+
+	/* Set the address wrapping on both MC and MMIO side */
+
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP0,
+							TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_WRAP1,
+							TEGRA_GPCDMA_MCSEQ_WRAP_NONE);
+	mmio_seq |= FIELD_PREP(TEGRA_GPCDMA_MMIOSEQ_WRAP_WORD, 1);
+
+	/* Program 2 MC outstanding requests by default. */
+	mc_seq |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_REQ_COUNT, 1);
+
+	/* Setting MC burst size depending on MMIO burst size */
+	if (burst_size == 64)
+		mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_16;
+	else
+		mc_seq |= TEGRA_GPCDMA_MCSEQ_BURST_2;
+
+	dma_desc = kzalloc(sizeof(*dma_desc), GFP_NOWAIT);
+	if (!dma_desc)
+		return NULL;
+
+	dma_desc->bytes_requested = 0;
+	dma_desc->bytes_transferred = 0;
+
+	/* Make transfer requests */
+	for_each_sg(sgl, sg, sg_len, i) {
+		u32 len;
+		dma_addr_t mem;
+
+		mem = sg_dma_address(sg);
+		len = sg_dma_len(sg);
+
+		if ((len & 3) || (mem & 3) ||
+		    len > tdc->tdma->chip_data->max_dma_count) {
+			dev_err(tdc2dev(tdc),
+				"DMA length/memory address is not supported\n");
+			kfree(dma_desc);
+			return NULL;
+		}
+
+		mmio_seq |= get_burst_size(tdc, burst_size, slave_bw, len);
+		dma_desc->bytes_requested += len;
+
+		if (direction == DMA_MEM_TO_DEV) {
+			dma_desc->ch_regs.src_ptr = mem;
+			dma_desc->ch_regs.dst_ptr = apb_ptr;
+			dma_desc->ch_regs.high_addr_ptr =
+				FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_SRC_PTR, (mem >> 32));
+		} else if (direction == DMA_DEV_TO_MEM) {
+			dma_desc->ch_regs.src_ptr = apb_ptr;
+			dma_desc->ch_regs.dst_ptr = mem;
+			dma_desc->ch_regs.high_addr_ptr =
+				FIELD_PREP(TEGRA_GPCDMA_HIGH_ADDR_DST_PTR, (mem >> 32));
+		}
+
+		/*
+		 * Word count register takes input in words. Writing a value
+		 * of N into word count register means a req of (N+1) words.
+		 */
+		dma_desc->ch_regs.wcount = ((len - 4) >> 2);
+		dma_desc->ch_regs.csr = csr;
+		dma_desc->ch_regs.mmio_seq = mmio_seq;
+		dma_desc->ch_regs.mc_seq = mc_seq;
+		tdc->dma_desc = dma_desc;
+	}
+
+	return vchan_tx_prep(&tdc->vc, &dma_desc->vd, flags);
+}
+
+static int tegra_dma_alloc_chan_resources(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+
+	dma_cookie_init(&tdc->vc.chan);
+	tdc->config_init = false;
+	return 0;
+}
+
+static void tegra_dma_chan_synchronize(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+
+	vchan_synchronize(&tdc->vc);
+}
+
+static void tegra_dma_free_chan_resources(struct dma_chan *dc)
+{
+	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
+	unsigned long flags;
+
+	dev_dbg(tdc2dev(tdc), "Freeing channel %d\n", tdc->id);
+
+	tegra_dma_terminate_all(dc);
+
+	tegra_dma_chan_synchronize(dc);
+
+	tasklet_kill(&tdc->vc.task);
+	raw_spin_lock_irqsave(&tdc->lock, flags);
+	tdc->config_init = false;
+	tdc->slave_id = -1;
+	tdc->sid_dir = DMA_TRANS_NONE;
+
+	raw_spin_unlock_irqrestore(&tdc->lock, flags);
+}
+
+static struct dma_chan *tegra_dma_of_xlate(struct of_phandle_args *dma_spec,
+					   struct of_dma *ofdma)
+{
+	struct tegra_dma *tdma = ofdma->of_dma_data;
+	struct tegra_dma_channel *tdc;
+	struct dma_chan *chan;
+
+	chan = dma_get_any_slave_channel(&tdma->dma_dev);
+	if (!chan)
+		return NULL;
+
+	tdc = to_tegra_dma_chan(chan);
+	tdc->slave_id = dma_spec->args[0];
+
+	return chan;
+}
+
+static const struct tegra_dma_chip_data tegra186_dma_chip_data = {
+	.nr_channels = 32,
+	.channel_reg_size = SZ_64K,
+	.max_dma_count = SZ_1G,
+	.hw_support_pause = false,
+};
+
+static const struct tegra_dma_chip_data tegra194_dma_chip_data = {
+	.nr_channels = 32,
+	.channel_reg_size = SZ_64K,
+	.max_dma_count = SZ_1G,
+	.hw_support_pause = true,
+};
+
+static const struct of_device_id tegra_dma_of_match[] = {
+	{
+		.compatible = "nvidia,tegra186-gpcdma",
+		.data = &tegra186_dma_chip_data,
+	}, {
+		.compatible = "nvidia,tegra194-gpcdma",
+		.data = &tegra194_dma_chip_data,
+	}, {
+	},
+};
+MODULE_DEVICE_TABLE(of, tegra_dma_of_match);
+
+static int tegra_dma_program_sid(struct tegra_dma_channel *tdc,
+				 int chan, int stream_id)
+{
+	unsigned int reg_val =  tdc_read(tdc, TEGRA_GPCDMA_CHAN_MCSEQ);
+
+	reg_val &= ~(TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK);
+	reg_val &= ~(TEGRA_GPCDMA_MCSEQ_STREAM_ID1_MASK);
+
+	reg_val |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_STREAM_ID0_MASK, stream_id);
+	reg_val |= FIELD_PREP(TEGRA_GPCDMA_MCSEQ_STREAM_ID1_MASK, stream_id);
+
+	tdc_write(tdc, TEGRA_GPCDMA_CHAN_MCSEQ, reg_val);
+	return 0;
+}
+
+static int tegra_dma_probe(struct platform_device *pdev)
+{
+	const struct tegra_dma_chip_data *cdata = NULL;
+	struct iommu_fwspec *iommu_spec;
+	unsigned int stream_id, i;
+	struct tegra_dma *tdma;
+	struct resource	*res;
+	int ret;
+
+	cdata = of_device_get_match_data(&pdev->dev);
+
+	tdma = devm_kzalloc(&pdev->dev, sizeof(*tdma) + cdata->nr_channels *
+			sizeof(struct tegra_dma_channel), GFP_KERNEL);
+	if (!tdma)
+		return -ENOMEM;
+
+	tdma->dev = &pdev->dev;
+	tdma->chip_data = cdata;
+	platform_set_drvdata(pdev, tdma);
+
+	tdma->base_addr = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(tdma->base_addr))
+		return PTR_ERR(tdma->base_addr);
+
+	tdma->rst = devm_reset_control_get_exclusive(&pdev->dev, "gpcdma");
+	if (IS_ERR(tdma->rst)) {
+		dev_err_probe(&pdev->dev, PTR_ERR(tdma->rst),
+			      "Missing controller reset\n");
+		return PTR_ERR(tdma->rst);
+	}
+	reset_control_reset(tdma->rst);
+
+	tdma->dma_dev.dev = &pdev->dev;
+
+	iommu_spec = dev_iommu_fwspec_get(&pdev->dev);
+	if (!iommu_spec) {
+		dev_err(&pdev->dev, "Missing iommu stream-id\n");
+		return -EINVAL;
+	}
+	stream_id = iommu_spec->ids[0] & 0xffff;
+
+	INIT_LIST_HEAD(&tdma->dma_dev.channels);
+	for (i = 0; i < cdata->nr_channels; i++) {
+		struct tegra_dma_channel *tdc = &tdma->channels[i];
+
+		tdc->chan_base_offset = TEGRA_GPCDMA_CHANNEL_BASE_ADD_OFFSET +
+					i * cdata->channel_reg_size;
+		res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
+		if (!res) {
+			dev_err(&pdev->dev, "No irq resource for chan %d\n", i);
+			return -EINVAL;
+		}
+		tdc->irq = res->start;
+		snprintf(tdc->name, sizeof(tdc->name), "gpcdma.%d", i);
+
+		tdc->tdma = tdma;
+		tdc->id = i;
+		tdc->slave_id = -1;
+
+		vchan_init(&tdc->vc, &tdma->dma_dev);
+		tdc->vc.desc_free = tegra_dma_desc_free;
+		raw_spin_lock_init(&tdc->lock);
+
+		/* program stream-id for this channel */
+		tegra_dma_program_sid(tdc, i, stream_id);
+		tdc->stream_id = stream_id;
+	}
+
+	dma_cap_set(DMA_SLAVE, tdma->dma_dev.cap_mask);
+	dma_cap_set(DMA_PRIVATE, tdma->dma_dev.cap_mask);
+	dma_cap_set(DMA_MEMCPY, tdma->dma_dev.cap_mask);
+	dma_cap_set(DMA_MEMSET, tdma->dma_dev.cap_mask);
+
+	/*
+	 * Only word aligned transfers are supported. Set the copy
+	 * alignment shift.
+	 */
+	tdma->dma_dev.copy_align = 2;
+	tdma->dma_dev.fill_align = 2;
+	tdma->dma_dev.device_alloc_chan_resources =
+					tegra_dma_alloc_chan_resources;
+	tdma->dma_dev.device_free_chan_resources =
+					tegra_dma_free_chan_resources;
+	tdma->dma_dev.device_prep_slave_sg = tegra_dma_prep_slave_sg;
+	tdma->dma_dev.device_prep_dma_memcpy = tegra_dma_prep_dma_memcpy;
+	tdma->dma_dev.device_prep_dma_memset = tegra_dma_prep_dma_memset;
+	tdma->dma_dev.device_config = tegra_dma_slave_config;
+	tdma->dma_dev.device_terminate_all = tegra_dma_terminate_all;
+	tdma->dma_dev.device_tx_status = tegra_dma_tx_status;
+	tdma->dma_dev.device_issue_pending = tegra_dma_issue_pending;
+	tdma->dma_dev.device_synchronize = tegra_dma_chan_synchronize;
+	tdma->dma_dev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+
+	/* Register DMA channel interrupt handlers after everything is setup */
+	for (i = 0; i < cdata->nr_channels; i++) {
+		struct tegra_dma_channel *tdc = &tdma->channels[i];
+
+		ret = devm_request_irq(&pdev->dev, tdc->irq,
+				       tegra_dma_isr, 0, tdc->name, tdc);
+		if (ret) {
+			dev_err_probe(&pdev->dev, ret,
+				      "request_irq failed for channel %d\n", i);
+			return ret;
+		}
+	}
+
+	ret = dma_async_device_register(&tdma->dma_dev);
+	if (ret < 0) {
+		dev_err_probe(&pdev->dev, ret,
+			      "GPC DMA driver registration failed\n");
+		return ret;
+	}
+
+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 tegra_dma_of_xlate, tdma);
+	if (ret < 0) {
+		dev_err_probe(&pdev->dev, ret,
+			      "GPC DMA OF registration failed\n");
+
+		dma_async_device_unregister(&tdma->dma_dev);
+		return ret;
+	}
+
+	dev_info(&pdev->dev, "GPC DMA driver register %d channels\n",
+		 cdata->nr_channels);
+
+	return 0;
+}
+
+static int tegra_dma_remove(struct platform_device *pdev)
+{
+	struct tegra_dma *tdma = platform_get_drvdata(pdev);
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&tdma->dma_dev);
+
+	return 0;
+}
+
+/*
+ * Save and restore csr and channel register on pm_suspend
+ * and pm_resume respectively
+ */
+static int __maybe_unused tegra_dma_pm_suspend(struct device *dev)
+{
+	struct tegra_dma *tdma = dev_get_drvdata(dev);
+	unsigned long flags;
+	unsigned int i;
+	bool busy;
+
+	for (i = 0; i < tdma->chip_data->nr_channels; i++) {
+		struct tegra_dma_channel *tdc = &tdma->channels[i];
+
+		raw_spin_lock_irqsave(&tdc->lock, flags);
+		busy = tdc->busy;
+		raw_spin_unlock_irqrestore(&tdc->lock, flags);
+
+		if (busy) {
+			dev_err(tdma->dev, "channel %u busy\n", i);
+			return -EBUSY;
+		}
+	}
+
+	return 0;
+}
+
+static int __maybe_unused tegra_dma_pm_resume(struct device *dev)
+{
+	struct tegra_dma *tdma = dev_get_drvdata(dev);
+	unsigned int i;
+
+	reset_control_reset(tdma->rst);
+
+	for (i = 0; i < tdma->chip_data->nr_channels; i++) {
+		struct tegra_dma_channel *tdc = &tdma->channels[i];
+
+		tegra_dma_program_sid(tdc, i, tdc->stream_id);
+	}
+
+	return 0;
+}
+
+static const struct __maybe_unused dev_pm_ops tegra_dma_dev_pm_ops = {
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(tegra_dma_pm_suspend, tegra_dma_pm_resume)
+};
+
+static struct platform_driver tegra_dmac_driver = {
+	.driver = {
+		.name	= "tegra-gpcdma",
+		.owner = THIS_MODULE,
+		.pm	= &tegra_dma_dev_pm_ops,
+		.of_match_table = tegra_dma_of_match,
+	},
+	.probe		= tegra_dma_probe,
+	.remove		= tegra_dma_remove,
+};
+
+module_platform_driver(tegra_dmac_driver);
+
+MODULE_ALIAS("platform:tegra-gpc-dma");
+MODULE_DESCRIPTION("NVIDIA Tegra GPC DMA Controller driver");
+MODULE_AUTHOR("Pavan Kunapuli <pkunapuli@...dia.com>");
+MODULE_AUTHOR("Rajesh Gumasta <rgumasta@...dia.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

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