Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1804 insertions, 0 deletions

diff --git a/drivers/dma/ipu/ipu_idmac.c b/drivers/dma/ipu/ipu_idmac.c
new file mode 100644
index 000000000..bbff52be4
--- /dev/null
+++ b/drivers/dma/ipu/ipu_idmac.c
@@ -0,0 +1,1804 @@
+/*
+ * Copyright (C) 2008
+ * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
+ *
+ * Copyright (C) 2005-2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <linux/list.h>
+#include <linux/clk.h>
+#include <linux/vmalloc.h>
+#include <linux/string.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/dma/ipu-dma.h>
+
+#include "../dmaengine.h"
+#include "ipu_intern.h"
+
+#define FS_VF_IN_VALID	0x00000002
+#define FS_ENC_IN_VALID	0x00000001
+
+static int ipu_disable_channel(struct idmac *idmac, struct idmac_channel *ichan,
+			       bool wait_for_stop);
+
+/*
+ * There can be only one, we could allocate it dynamically, but then we'd have
+ * to add an extra parameter to some functions, and use something as ugly as
+ *	struct ipu *ipu = to_ipu(to_idmac(ichan->dma_chan.device));
+ * in the ISR
+ */
+static struct ipu ipu_data;
+
+#define to_ipu(id) container_of(id, struct ipu, idmac)
+
+static u32 __idmac_read_icreg(struct ipu *ipu, unsigned long reg)
+{
+	return __raw_readl(ipu->reg_ic + reg);
+}
+
+#define idmac_read_icreg(ipu, reg) __idmac_read_icreg(ipu, reg - IC_CONF)
+
+static void __idmac_write_icreg(struct ipu *ipu, u32 value, unsigned long reg)
+{
+	__raw_writel(value, ipu->reg_ic + reg);
+}
+
+#define idmac_write_icreg(ipu, v, reg) __idmac_write_icreg(ipu, v, reg - IC_CONF)
+
+static u32 idmac_read_ipureg(struct ipu *ipu, unsigned long reg)
+{
+	return __raw_readl(ipu->reg_ipu + reg);
+}
+
+static void idmac_write_ipureg(struct ipu *ipu, u32 value, unsigned long reg)
+{
+	__raw_writel(value, ipu->reg_ipu + reg);
+}
+
+/*****************************************************************************
+ * IPU / IC common functions
+ */
+static void dump_idmac_reg(struct ipu *ipu)
+{
+	dev_dbg(ipu->dev, "IDMAC_CONF 0x%x, IC_CONF 0x%x, IDMAC_CHA_EN 0x%x, "
+		"IDMAC_CHA_PRI 0x%x, IDMAC_CHA_BUSY 0x%x\n",
+		idmac_read_icreg(ipu, IDMAC_CONF),
+		idmac_read_icreg(ipu, IC_CONF),
+		idmac_read_icreg(ipu, IDMAC_CHA_EN),
+		idmac_read_icreg(ipu, IDMAC_CHA_PRI),
+		idmac_read_icreg(ipu, IDMAC_CHA_BUSY));
+	dev_dbg(ipu->dev, "BUF0_RDY 0x%x, BUF1_RDY 0x%x, CUR_BUF 0x%x, "
+		"DB_MODE 0x%x, TASKS_STAT 0x%x\n",
+		idmac_read_ipureg(ipu, IPU_CHA_BUF0_RDY),
+		idmac_read_ipureg(ipu, IPU_CHA_BUF1_RDY),
+		idmac_read_ipureg(ipu, IPU_CHA_CUR_BUF),
+		idmac_read_ipureg(ipu, IPU_CHA_DB_MODE_SEL),
+		idmac_read_ipureg(ipu, IPU_TASKS_STAT));
+}
+
+static uint32_t bytes_per_pixel(enum pixel_fmt fmt)
+{
+	switch (fmt) {
+	case IPU_PIX_FMT_GENERIC:	/* generic data */
+	case IPU_PIX_FMT_RGB332:
+	case IPU_PIX_FMT_YUV420P:
+	case IPU_PIX_FMT_YUV422P:
+	default:
+		return 1;
+	case IPU_PIX_FMT_RGB565:
+	case IPU_PIX_FMT_YUYV:
+	case IPU_PIX_FMT_UYVY:
+		return 2;
+	case IPU_PIX_FMT_BGR24:
+	case IPU_PIX_FMT_RGB24:
+		return 3;
+	case IPU_PIX_FMT_GENERIC_32:	/* generic data */
+	case IPU_PIX_FMT_BGR32:
+	case IPU_PIX_FMT_RGB32:
+	case IPU_PIX_FMT_ABGR32:
+		return 4;
+	}
+}
+
+/* Enable direct write to memory by the Camera Sensor Interface */
+static void ipu_ic_enable_task(struct ipu *ipu, enum ipu_channel channel)
+{
+	uint32_t ic_conf, mask;
+
+	switch (channel) {
+	case IDMAC_IC_0:
+		mask = IC_CONF_PRPENC_EN;
+		break;
+	case IDMAC_IC_7:
+		mask = IC_CONF_RWS_EN | IC_CONF_PRPENC_EN;
+		break;
+	default:
+		return;
+	}
+	ic_conf = idmac_read_icreg(ipu, IC_CONF) | mask;
+	idmac_write_icreg(ipu, ic_conf, IC_CONF);
+}
+
+/* Called under spin_lock_irqsave(&ipu_data.lock) */
+static void ipu_ic_disable_task(struct ipu *ipu, enum ipu_channel channel)
+{
+	uint32_t ic_conf, mask;
+
+	switch (channel) {
+	case IDMAC_IC_0:
+		mask = IC_CONF_PRPENC_EN;
+		break;
+	case IDMAC_IC_7:
+		mask = IC_CONF_RWS_EN | IC_CONF_PRPENC_EN;
+		break;
+	default:
+		return;
+	}
+	ic_conf = idmac_read_icreg(ipu, IC_CONF) & ~mask;
+	idmac_write_icreg(ipu, ic_conf, IC_CONF);
+}
+
+static uint32_t ipu_channel_status(struct ipu *ipu, enum ipu_channel channel)
+{
+	uint32_t stat = TASK_STAT_IDLE;
+	uint32_t task_stat_reg = idmac_read_ipureg(ipu, IPU_TASKS_STAT);
+
+	switch (channel) {
+	case IDMAC_IC_7:
+		stat = (task_stat_reg & TSTAT_CSI2MEM_MASK) >>
+			TSTAT_CSI2MEM_OFFSET;
+		break;
+	case IDMAC_IC_0:
+	case IDMAC_SDC_0:
+	case IDMAC_SDC_1:
+	default:
+		break;
+	}
+	return stat;
+}
+
+struct chan_param_mem_planar {
+	/* Word 0 */
+	u32	xv:10;
+	u32	yv:10;
+	u32	xb:12;
+
+	u32	yb:12;
+	u32	res1:2;
+	u32	nsb:1;
+	u32	lnpb:6;
+	u32	ubo_l:11;
+
+	u32	ubo_h:15;
+	u32	vbo_l:17;
+
+	u32	vbo_h:9;
+	u32	res2:3;
+	u32	fw:12;
+	u32	fh_l:8;
+
+	u32	fh_h:4;
+	u32	res3:28;
+
+	/* Word 1 */
+	u32	eba0;
+
+	u32	eba1;
+
+	u32	bpp:3;
+	u32	sl:14;
+	u32	pfs:3;
+	u32	bam:3;
+	u32	res4:2;
+	u32	npb:6;
+	u32	res5:1;
+
+	u32	sat:2;
+	u32	res6:30;
+} __attribute__ ((packed));
+
+struct chan_param_mem_interleaved {
+	/* Word 0 */
+	u32	xv:10;
+	u32	yv:10;
+	u32	xb:12;
+
+	u32	yb:12;
+	u32	sce:1;
+	u32	res1:1;
+	u32	nsb:1;
+	u32	lnpb:6;
+	u32	sx:10;
+	u32	sy_l:1;
+
+	u32	sy_h:9;
+	u32	ns:10;
+	u32	sm:10;
+	u32	sdx_l:3;
+
+	u32	sdx_h:2;
+	u32	sdy:5;
+	u32	sdrx:1;
+	u32	sdry:1;
+	u32	sdr1:1;
+	u32	res2:2;
+	u32	fw:12;
+	u32	fh_l:8;
+
+	u32	fh_h:4;
+	u32	res3:28;
+
+	/* Word 1 */
+	u32	eba0;
+
+	u32	eba1;
+
+	u32	bpp:3;
+	u32	sl:14;
+	u32	pfs:3;
+	u32	bam:3;
+	u32	res4:2;
+	u32	npb:6;
+	u32	res5:1;
+
+	u32	sat:2;
+	u32	scc:1;
+	u32	ofs0:5;
+	u32	ofs1:5;
+	u32	ofs2:5;
+	u32	ofs3:5;
+	u32	wid0:3;
+	u32	wid1:3;
+	u32	wid2:3;
+
+	u32	wid3:3;
+	u32	dec_sel:1;
+	u32	res6:28;
+} __attribute__ ((packed));
+
+union chan_param_mem {
+	struct chan_param_mem_planar		pp;
+	struct chan_param_mem_interleaved	ip;
+};
+
+static void ipu_ch_param_set_plane_offset(union chan_param_mem *params,
+					  u32 u_offset, u32 v_offset)
+{
+	params->pp.ubo_l = u_offset & 0x7ff;
+	params->pp.ubo_h = u_offset >> 11;
+	params->pp.vbo_l = v_offset & 0x1ffff;
+	params->pp.vbo_h = v_offset >> 17;
+}
+
+static void ipu_ch_param_set_size(union chan_param_mem *params,
+				  uint32_t pixel_fmt, uint16_t width,
+				  uint16_t height, uint16_t stride)
+{
+	u32 u_offset;
+	u32 v_offset;
+
+	params->pp.fw		= width - 1;
+	params->pp.fh_l		= height - 1;
+	params->pp.fh_h		= (height - 1) >> 8;
+	params->pp.sl		= stride - 1;
+
+	switch (pixel_fmt) {
+	case IPU_PIX_FMT_GENERIC:
+		/*Represents 8-bit Generic data */
+		params->pp.bpp	= 3;
+		params->pp.pfs	= 7;
+		params->pp.npb	= 31;
+		params->pp.sat	= 2;		/* SAT = use 32-bit access */
+		break;
+	case IPU_PIX_FMT_GENERIC_32:
+		/*Represents 32-bit Generic data */
+		params->pp.bpp	= 0;
+		params->pp.pfs	= 7;
+		params->pp.npb	= 7;
+		params->pp.sat	= 2;		/* SAT = use 32-bit access */
+		break;
+	case IPU_PIX_FMT_RGB565:
+		params->ip.bpp	= 2;
+		params->ip.pfs	= 4;
+		params->ip.npb	= 15;
+		params->ip.sat	= 2;		/* SAT = 32-bit access */
+		params->ip.ofs0	= 0;		/* Red bit offset */
+		params->ip.ofs1	= 5;		/* Green bit offset */
+		params->ip.ofs2	= 11;		/* Blue bit offset */
+		params->ip.ofs3	= 16;		/* Alpha bit offset */
+		params->ip.wid0	= 4;		/* Red bit width - 1 */
+		params->ip.wid1	= 5;		/* Green bit width - 1 */
+		params->ip.wid2	= 4;		/* Blue bit width - 1 */
+		break;
+	case IPU_PIX_FMT_BGR24:
+		params->ip.bpp	= 1;		/* 24 BPP & RGB PFS */
+		params->ip.pfs	= 4;
+		params->ip.npb	= 7;
+		params->ip.sat	= 2;		/* SAT = 32-bit access */
+		params->ip.ofs0	= 0;		/* Red bit offset */
+		params->ip.ofs1	= 8;		/* Green bit offset */
+		params->ip.ofs2	= 16;		/* Blue bit offset */
+		params->ip.ofs3	= 24;		/* Alpha bit offset */
+		params->ip.wid0	= 7;		/* Red bit width - 1 */
+		params->ip.wid1	= 7;		/* Green bit width - 1 */
+		params->ip.wid2	= 7;		/* Blue bit width - 1 */
+		break;
+	case IPU_PIX_FMT_RGB24:
+		params->ip.bpp	= 1;		/* 24 BPP & RGB PFS */
+		params->ip.pfs	= 4;
+		params->ip.npb	= 7;
+		params->ip.sat	= 2;		/* SAT = 32-bit access */
+		params->ip.ofs0	= 16;		/* Red bit offset */
+		params->ip.ofs1	= 8;		/* Green bit offset */
+		params->ip.ofs2	= 0;		/* Blue bit offset */
+		params->ip.ofs3	= 24;		/* Alpha bit offset */
+		params->ip.wid0	= 7;		/* Red bit width - 1 */
+		params->ip.wid1	= 7;		/* Green bit width - 1 */
+		params->ip.wid2	= 7;		/* Blue bit width - 1 */
+		break;
+	case IPU_PIX_FMT_BGRA32:
+	case IPU_PIX_FMT_BGR32:
+	case IPU_PIX_FMT_ABGR32:
+		params->ip.bpp	= 0;
+		params->ip.pfs	= 4;
+		params->ip.npb	= 7;
+		params->ip.sat	= 2;		/* SAT = 32-bit access */
+		params->ip.ofs0	= 8;		/* Red bit offset */
+		params->ip.ofs1	= 16;		/* Green bit offset */
+		params->ip.ofs2	= 24;		/* Blue bit offset */
+		params->ip.ofs3	= 0;		/* Alpha bit offset */
+		params->ip.wid0	= 7;		/* Red bit width - 1 */
+		params->ip.wid1	= 7;		/* Green bit width - 1 */
+		params->ip.wid2	= 7;		/* Blue bit width - 1 */
+		params->ip.wid3	= 7;		/* Alpha bit width - 1 */
+		break;
+	case IPU_PIX_FMT_RGBA32:
+	case IPU_PIX_FMT_RGB32:
+		params->ip.bpp	= 0;
+		params->ip.pfs	= 4;
+		params->ip.npb	= 7;
+		params->ip.sat	= 2;		/* SAT = 32-bit access */
+		params->ip.ofs0	= 24;		/* Red bit offset */
+		params->ip.ofs1	= 16;		/* Green bit offset */
+		params->ip.ofs2	= 8;		/* Blue bit offset */
+		params->ip.ofs3	= 0;		/* Alpha bit offset */
+		params->ip.wid0	= 7;		/* Red bit width - 1 */
+		params->ip.wid1	= 7;		/* Green bit width - 1 */
+		params->ip.wid2	= 7;		/* Blue bit width - 1 */
+		params->ip.wid3	= 7;		/* Alpha bit width - 1 */
+		break;
+	case IPU_PIX_FMT_UYVY:
+		params->ip.bpp	= 2;
+		params->ip.pfs	= 6;
+		params->ip.npb	= 7;
+		params->ip.sat	= 2;		/* SAT = 32-bit access */
+		break;
+	case IPU_PIX_FMT_YUV420P2:
+	case IPU_PIX_FMT_YUV420P:
+		params->ip.bpp	= 3;
+		params->ip.pfs	= 3;
+		params->ip.npb	= 7;
+		params->ip.sat	= 2;		/* SAT = 32-bit access */
+		u_offset = stride * height;
+		v_offset = u_offset + u_offset / 4;
+		ipu_ch_param_set_plane_offset(params, u_offset, v_offset);
+		break;
+	case IPU_PIX_FMT_YVU422P:
+		params->ip.bpp	= 3;
+		params->ip.pfs	= 2;
+		params->ip.npb	= 7;
+		params->ip.sat	= 2;		/* SAT = 32-bit access */
+		v_offset = stride * height;
+		u_offset = v_offset + v_offset / 2;
+		ipu_ch_param_set_plane_offset(params, u_offset, v_offset);
+		break;
+	case IPU_PIX_FMT_YUV422P:
+		params->ip.bpp	= 3;
+		params->ip.pfs	= 2;
+		params->ip.npb	= 7;
+		params->ip.sat	= 2;		/* SAT = 32-bit access */
+		u_offset = stride * height;
+		v_offset = u_offset + u_offset / 2;
+		ipu_ch_param_set_plane_offset(params, u_offset, v_offset);
+		break;
+	default:
+		dev_err(ipu_data.dev,
+			"mx3 ipu: unimplemented pixel format %d\n", pixel_fmt);
+		break;
+	}
+
+	params->pp.nsb = 1;
+}
+
+static void ipu_ch_param_set_buffer(union chan_param_mem *params,
+				    dma_addr_t buf0, dma_addr_t buf1)
+{
+	params->pp.eba0 = buf0;
+	params->pp.eba1 = buf1;
+}
+
+static void ipu_ch_param_set_rotation(union chan_param_mem *params,
+				      enum ipu_rotate_mode rotate)
+{
+	params->pp.bam = rotate;
+}
+
+static void ipu_write_param_mem(uint32_t addr, uint32_t *data,
+				uint32_t num_words)
+{
+	for (; num_words > 0; num_words--) {
+		dev_dbg(ipu_data.dev,
+			"write param mem - addr = 0x%08X, data = 0x%08X\n",
+			addr, *data);
+		idmac_write_ipureg(&ipu_data, addr, IPU_IMA_ADDR);
+		idmac_write_ipureg(&ipu_data, *data++, IPU_IMA_DATA);
+		addr++;
+		if ((addr & 0x7) == 5) {
+			addr &= ~0x7;	/* set to word 0 */
+			addr += 8;	/* increment to next row */
+		}
+	}
+}
+
+static int calc_resize_coeffs(uint32_t in_size, uint32_t out_size,
+			      uint32_t *resize_coeff,
+			      uint32_t *downsize_coeff)
+{
+	uint32_t temp_size;
+	uint32_t temp_downsize;
+
+	*resize_coeff	= 1 << 13;
+	*downsize_coeff	= 1 << 13;
+
+	/* Cannot downsize more than 8:1 */
+	if (out_size << 3 < in_size)
+		return -EINVAL;
+
+	/* compute downsizing coefficient */
+	temp_downsize = 0;
+	temp_size = in_size;
+	while (temp_size >= out_size * 2 && temp_downsize < 2) {
+		temp_size >>= 1;
+		temp_downsize++;
+	}
+	*downsize_coeff = temp_downsize;
+
+	/*
+	 * compute resizing coefficient using the following formula:
+	 * resize_coeff = M*(SI -1)/(SO - 1)
+	 * where M = 2^13, SI - input size, SO - output size
+	 */
+	*resize_coeff = (8192L * (temp_size - 1)) / (out_size - 1);
+	if (*resize_coeff >= 16384L) {
+		dev_err(ipu_data.dev, "Warning! Overflow on resize coeff.\n");
+		*resize_coeff = 0x3FFF;
+	}
+
+	dev_dbg(ipu_data.dev, "resizing from %u -> %u pixels, "
+		"downsize=%u, resize=%u.%lu (reg=%u)\n", in_size, out_size,
+		*downsize_coeff, *resize_coeff >= 8192L ? 1 : 0,
+		((*resize_coeff & 0x1FFF) * 10000L) / 8192L, *resize_coeff);
+
+	return 0;
+}
+
+static enum ipu_color_space format_to_colorspace(enum pixel_fmt fmt)
+{
+	switch (fmt) {
+	case IPU_PIX_FMT_RGB565:
+	case IPU_PIX_FMT_BGR24:
+	case IPU_PIX_FMT_RGB24:
+	case IPU_PIX_FMT_BGR32:
+	case IPU_PIX_FMT_RGB32:
+		return IPU_COLORSPACE_RGB;
+	default:
+		return IPU_COLORSPACE_YCBCR;
+	}
+}
+
+static int ipu_ic_init_prpenc(struct ipu *ipu,
+			      union ipu_channel_param *params, bool src_is_csi)
+{
+	uint32_t reg, ic_conf;
+	uint32_t downsize_coeff, resize_coeff;
+	enum ipu_color_space in_fmt, out_fmt;
+
+	/* Setup vertical resizing */
+	calc_resize_coeffs(params->video.in_height,
+			    params->video.out_height,
+			    &resize_coeff, &downsize_coeff);
+	reg = (downsize_coeff << 30) | (resize_coeff << 16);
+
+	/* Setup horizontal resizing */
+	calc_resize_coeffs(params->video.in_width,
+			    params->video.out_width,
+			    &resize_coeff, &downsize_coeff);
+	reg |= (downsize_coeff << 14) | resize_coeff;
+
+	/* Setup color space conversion */
+	in_fmt = format_to_colorspace(params->video.in_pixel_fmt);
+	out_fmt = format_to_colorspace(params->video.out_pixel_fmt);
+
+	/*
+	 * Colourspace conversion unsupported yet - see _init_csc() in
+	 * Freescale sources
+	 */
+	if (in_fmt != out_fmt) {
+		dev_err(ipu->dev, "Colourspace conversion unsupported!\n");
+		return -EOPNOTSUPP;
+	}
+
+	idmac_write_icreg(ipu, reg, IC_PRP_ENC_RSC);
+
+	ic_conf = idmac_read_icreg(ipu, IC_CONF);
+
+	if (src_is_csi)
+		ic_conf &= ~IC_CONF_RWS_EN;
+	else
+		ic_conf |= IC_CONF_RWS_EN;
+
+	idmac_write_icreg(ipu, ic_conf, IC_CONF);
+
+	return 0;
+}
+
+static uint32_t dma_param_addr(uint32_t dma_ch)
+{
+	/* Channel Parameter Memory */
+	return 0x10000 | (dma_ch << 4);
+}
+
+static void ipu_channel_set_priority(struct ipu *ipu, enum ipu_channel channel,
+				     bool prio)
+{
+	u32 reg = idmac_read_icreg(ipu, IDMAC_CHA_PRI);
+
+	if (prio)
+		reg |= 1UL << channel;
+	else
+		reg &= ~(1UL << channel);
+
+	idmac_write_icreg(ipu, reg, IDMAC_CHA_PRI);
+
+	dump_idmac_reg(ipu);
+}
+
+static uint32_t ipu_channel_conf_mask(enum ipu_channel channel)
+{
+	uint32_t mask;
+
+	switch (channel) {
+	case IDMAC_IC_0:
+	case IDMAC_IC_7:
+		mask = IPU_CONF_CSI_EN | IPU_CONF_IC_EN;
+		break;
+	case IDMAC_SDC_0:
+	case IDMAC_SDC_1:
+		mask = IPU_CONF_SDC_EN | IPU_CONF_DI_EN;
+		break;
+	default:
+		mask = 0;
+		break;
+	}
+
+	return mask;
+}
+
+/**
+ * ipu_enable_channel() - enable an IPU channel.
+ * @idmac:	IPU DMAC context.
+ * @ichan:	IDMAC channel.
+ * @return:	0 on success or negative error code on failure.
+ */
+static int ipu_enable_channel(struct idmac *idmac, struct idmac_channel *ichan)
+{
+	struct ipu *ipu = to_ipu(idmac);
+	enum ipu_channel channel = ichan->dma_chan.chan_id;
+	uint32_t reg;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ipu->lock, flags);
+
+	/* Reset to buffer 0 */
+	idmac_write_ipureg(ipu, 1UL << channel, IPU_CHA_CUR_BUF);
+	ichan->active_buffer = 0;
+	ichan->status = IPU_CHANNEL_ENABLED;
+
+	switch (channel) {
+	case IDMAC_SDC_0:
+	case IDMAC_SDC_1:
+	case IDMAC_IC_7:
+		ipu_channel_set_priority(ipu, channel, true);
+	default:
+		break;
+	}
+
+	reg = idmac_read_icreg(ipu, IDMAC_CHA_EN);
+
+	idmac_write_icreg(ipu, reg | (1UL << channel), IDMAC_CHA_EN);
+
+	ipu_ic_enable_task(ipu, channel);
+
+	spin_unlock_irqrestore(&ipu->lock, flags);
+	return 0;
+}
+
+/**
+ * ipu_init_channel_buffer() - initialize a buffer for logical IPU channel.
+ * @ichan:	IDMAC channel.
+ * @pixel_fmt:	pixel format of buffer. Pixel format is a FOURCC ASCII code.
+ * @width:	width of buffer in pixels.
+ * @height:	height of buffer in pixels.
+ * @stride:	stride length of buffer in pixels.
+ * @rot_mode:	rotation mode of buffer. A rotation setting other than
+ *		IPU_ROTATE_VERT_FLIP should only be used for input buffers of
+ *		rotation channels.
+ * @phyaddr_0:	buffer 0 physical address.
+ * @phyaddr_1:	buffer 1 physical address. Setting this to a value other than
+ *		NULL enables double buffering mode.
+ * @return:	0 on success or negative error code on failure.
+ */
+static int ipu_init_channel_buffer(struct idmac_channel *ichan,
+				   enum pixel_fmt pixel_fmt,
+				   uint16_t width, uint16_t height,
+				   uint32_t stride,
+				   enum ipu_rotate_mode rot_mode,
+				   dma_addr_t phyaddr_0, dma_addr_t phyaddr_1)
+{
+	enum ipu_channel channel = ichan->dma_chan.chan_id;
+	struct idmac *idmac = to_idmac(ichan->dma_chan.device);
+	struct ipu *ipu = to_ipu(idmac);
+	union chan_param_mem params = {};
+	unsigned long flags;
+	uint32_t reg;
+	uint32_t stride_bytes;
+
+	stride_bytes = stride * bytes_per_pixel(pixel_fmt);
+
+	if (stride_bytes % 4) {
+		dev_err(ipu->dev,
+			"Stride length must be 32-bit aligned, stride = %d, bytes = %d\n",
+			stride, stride_bytes);
+		return -EINVAL;
+	}
+
+	/* IC channel's stride must be a multiple of 8 pixels */
+	if ((channel <= IDMAC_IC_13) && (stride % 8)) {
+		dev_err(ipu->dev, "Stride must be 8 pixel multiple\n");
+		return -EINVAL;
+	}
+
+	/* Build parameter memory data for DMA channel */
+	ipu_ch_param_set_size(&params, pixel_fmt, width, height, stride_bytes);
+	ipu_ch_param_set_buffer(&params, phyaddr_0, phyaddr_1);
+	ipu_ch_param_set_rotation(&params, rot_mode);
+
+	spin_lock_irqsave(&ipu->lock, flags);
+
+	ipu_write_param_mem(dma_param_addr(channel), (uint32_t *)&params, 10);
+
+	reg = idmac_read_ipureg(ipu, IPU_CHA_DB_MODE_SEL);
+
+	if (phyaddr_1)
+		reg |= 1UL << channel;
+	else
+		reg &= ~(1UL << channel);
+
+	idmac_write_ipureg(ipu, reg, IPU_CHA_DB_MODE_SEL);
+
+	ichan->status = IPU_CHANNEL_READY;
+
+	spin_unlock_irqrestore(&ipu->lock, flags);
+
+	return 0;
+}
+
+/**
+ * ipu_select_buffer() - mark a channel's buffer as ready.
+ * @channel:	channel ID.
+ * @buffer_n:	buffer number to mark ready.
+ */
+static void ipu_select_buffer(enum ipu_channel channel, int buffer_n)
+{
+	/* No locking - this is a write-one-to-set register, cleared by IPU */
+	if (buffer_n == 0)
+		/* Mark buffer 0 as ready. */
+		idmac_write_ipureg(&ipu_data, 1UL << channel, IPU_CHA_BUF0_RDY);
+	else
+		/* Mark buffer 1 as ready. */
+		idmac_write_ipureg(&ipu_data, 1UL << channel, IPU_CHA_BUF1_RDY);
+}
+
+/**
+ * ipu_update_channel_buffer() - update physical address of a channel buffer.
+ * @ichan:	IDMAC channel.
+ * @buffer_n:	buffer number to update.
+ *		0 or 1 are the only valid values.
+ * @phyaddr:	buffer physical address.
+ */
+/* Called under spin_lock(_irqsave)(&ichan->lock) */
+static void ipu_update_channel_buffer(struct idmac_channel *ichan,
+				      int buffer_n, dma_addr_t phyaddr)
+{
+	enum ipu_channel channel = ichan->dma_chan.chan_id;
+	uint32_t reg;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ipu_data.lock, flags);
+
+	if (buffer_n == 0) {
+		reg = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF0_RDY);
+		if (reg & (1UL << channel)) {
+			ipu_ic_disable_task(&ipu_data, channel);
+			ichan->status = IPU_CHANNEL_READY;
+		}
+
+		/* 44.3.3.1.9 - Row Number 1 (WORD1, offset 0) */
+		idmac_write_ipureg(&ipu_data, dma_param_addr(channel) +
+				   0x0008UL, IPU_IMA_ADDR);
+		idmac_write_ipureg(&ipu_data, phyaddr, IPU_IMA_DATA);
+	} else {
+		reg = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF1_RDY);
+		if (reg & (1UL << channel)) {
+			ipu_ic_disable_task(&ipu_data, channel);
+			ichan->status = IPU_CHANNEL_READY;
+		}
+
+		/* Check if double-buffering is already enabled */
+		reg = idmac_read_ipureg(&ipu_data, IPU_CHA_DB_MODE_SEL);
+
+		if (!(reg & (1UL << channel)))
+			idmac_write_ipureg(&ipu_data, reg | (1UL << channel),
+					   IPU_CHA_DB_MODE_SEL);
+
+		/* 44.3.3.1.9 - Row Number 1 (WORD1, offset 1) */
+		idmac_write_ipureg(&ipu_data, dma_param_addr(channel) +
+				   0x0009UL, IPU_IMA_ADDR);
+		idmac_write_ipureg(&ipu_data, phyaddr, IPU_IMA_DATA);
+	}
+
+	spin_unlock_irqrestore(&ipu_data.lock, flags);
+}
+
+/* Called under spin_lock_irqsave(&ichan->lock) */
+static int ipu_submit_buffer(struct idmac_channel *ichan,
+	struct idmac_tx_desc *desc, struct scatterlist *sg, int buf_idx)
+{
+	unsigned int chan_id = ichan->dma_chan.chan_id;
+	struct device *dev = &ichan->dma_chan.dev->device;
+
+	if (async_tx_test_ack(&desc->txd))
+		return -EINTR;
+
+	/*
+	 * On first invocation this shouldn't be necessary, the call to
+	 * ipu_init_channel_buffer() above will set addresses for us, so we
+	 * could make it conditional on status >= IPU_CHANNEL_ENABLED, but
+	 * doing it again shouldn't hurt either.
+	 */
+	ipu_update_channel_buffer(ichan, buf_idx, sg_dma_address(sg));
+
+	ipu_select_buffer(chan_id, buf_idx);
+	dev_dbg(dev, "Updated sg %p on channel 0x%x buffer %d\n",
+		sg, chan_id, buf_idx);
+
+	return 0;
+}
+
+/* Called under spin_lock_irqsave(&ichan->lock) */
+static int ipu_submit_channel_buffers(struct idmac_channel *ichan,
+				      struct idmac_tx_desc *desc)
+{
+	struct scatterlist *sg;
+	int i, ret = 0;
+
+	for (i = 0, sg = desc->sg; i < 2 && sg; i++) {
+		if (!ichan->sg[i]) {
+			ichan->sg[i] = sg;
+
+			ret = ipu_submit_buffer(ichan, desc, sg, i);
+			if (ret < 0)
+				return ret;
+
+			sg = sg_next(sg);
+		}
+	}
+
+	return ret;
+}
+
+static dma_cookie_t idmac_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	struct idmac_tx_desc *desc = to_tx_desc(tx);
+	struct idmac_channel *ichan = to_idmac_chan(tx->chan);
+	struct idmac *idmac = to_idmac(tx->chan->device);
+	struct ipu *ipu = to_ipu(idmac);
+	struct device *dev = &ichan->dma_chan.dev->device;
+	dma_cookie_t cookie;
+	unsigned long flags;
+	int ret;
+
+	/* Sanity check */
+	if (!list_empty(&desc->list)) {
+		/* The descriptor doesn't belong to client */
+		dev_err(dev, "Descriptor %p not prepared!\n", tx);
+		return -EBUSY;
+	}
+
+	mutex_lock(&ichan->chan_mutex);
+
+	async_tx_clear_ack(tx);
+
+	if (ichan->status < IPU_CHANNEL_READY) {
+		struct idmac_video_param *video = &ichan->params.video;
+		/*
+		 * Initial buffer assignment - the first two sg-entries from
+		 * the descriptor will end up in the IDMAC buffers
+		 */
+		dma_addr_t dma_1 = sg_is_last(desc->sg) ? 0 :
+			sg_dma_address(&desc->sg[1]);
+
+		WARN_ON(ichan->sg[0] || ichan->sg[1]);
+
+		cookie = ipu_init_channel_buffer(ichan,
+						 video->out_pixel_fmt,
+						 video->out_width,
+						 video->out_height,
+						 video->out_stride,
+						 IPU_ROTATE_NONE,
+						 sg_dma_address(&desc->sg[0]),
+						 dma_1);
+		if (cookie < 0)
+			goto out;
+	}
+
+	dev_dbg(dev, "Submitting sg %p\n", &desc->sg[0]);
+
+	cookie = dma_cookie_assign(tx);
+
+	/* ipu->lock can be taken under ichan->lock, but not v.v. */
+	spin_lock_irqsave(&ichan->lock, flags);
+
+	list_add_tail(&desc->list, &ichan->queue);
+	/* submit_buffers() atomically verifies and fills empty sg slots */
+	ret = ipu_submit_channel_buffers(ichan, desc);
+
+	spin_unlock_irqrestore(&ichan->lock, flags);
+
+	if (ret < 0) {
+		cookie = ret;
+		goto dequeue;
+	}
+
+	if (ichan->status < IPU_CHANNEL_ENABLED) {
+		ret = ipu_enable_channel(idmac, ichan);
+		if (ret < 0) {
+			cookie = ret;
+			goto dequeue;
+		}
+	}
+
+	dump_idmac_reg(ipu);
+
+dequeue:
+	if (cookie < 0) {
+		spin_lock_irqsave(&ichan->lock, flags);
+		list_del_init(&desc->list);
+		spin_unlock_irqrestore(&ichan->lock, flags);
+		tx->cookie = cookie;
+		ichan->dma_chan.cookie = cookie;
+	}
+
+out:
+	mutex_unlock(&ichan->chan_mutex);
+
+	return cookie;
+}
+
+/* Called with ichan->chan_mutex held */
+static int idmac_desc_alloc(struct idmac_channel *ichan, int n)
+{
+	struct idmac_tx_desc *desc =
+		vmalloc(array_size(n, sizeof(struct idmac_tx_desc)));
+	struct idmac *idmac = to_idmac(ichan->dma_chan.device);
+
+	if (!desc)
+		return -ENOMEM;
+
+	/* No interrupts, just disable the tasklet for a moment */
+	tasklet_disable(&to_ipu(idmac)->tasklet);
+
+	ichan->n_tx_desc = n;
+	ichan->desc = desc;
+	INIT_LIST_HEAD(&ichan->queue);
+	INIT_LIST_HEAD(&ichan->free_list);
+
+	while (n--) {
+		struct dma_async_tx_descriptor *txd = &desc->txd;
+
+		memset(txd, 0, sizeof(*txd));
+		dma_async_tx_descriptor_init(txd, &ichan->dma_chan);
+		txd->tx_submit		= idmac_tx_submit;
+
+		list_add(&desc->list, &ichan->free_list);
+
+		desc++;
+	}
+
+	tasklet_enable(&to_ipu(idmac)->tasklet);
+
+	return 0;
+}
+
+/**
+ * ipu_init_channel() - initialize an IPU channel.
+ * @idmac:	IPU DMAC context.
+ * @ichan:	pointer to the channel object.
+ * @return      0 on success or negative error code on failure.
+ */
+static int ipu_init_channel(struct idmac *idmac, struct idmac_channel *ichan)
+{
+	union ipu_channel_param *params = &ichan->params;
+	uint32_t ipu_conf;
+	enum ipu_channel channel = ichan->dma_chan.chan_id;
+	unsigned long flags;
+	uint32_t reg;
+	struct ipu *ipu = to_ipu(idmac);
+	int ret = 0, n_desc = 0;
+
+	dev_dbg(ipu->dev, "init channel = %d\n", channel);
+
+	if (channel != IDMAC_SDC_0 && channel != IDMAC_SDC_1 &&
+	    channel != IDMAC_IC_7)
+		return -EINVAL;
+
+	spin_lock_irqsave(&ipu->lock, flags);
+
+	switch (channel) {
+	case IDMAC_IC_7:
+		n_desc = 16;
+		reg = idmac_read_icreg(ipu, IC_CONF);
+		idmac_write_icreg(ipu, reg & ~IC_CONF_CSI_MEM_WR_EN, IC_CONF);
+		break;
+	case IDMAC_IC_0:
+		n_desc = 16;
+		reg = idmac_read_ipureg(ipu, IPU_FS_PROC_FLOW);
+		idmac_write_ipureg(ipu, reg & ~FS_ENC_IN_VALID, IPU_FS_PROC_FLOW);
+		ret = ipu_ic_init_prpenc(ipu, params, true);
+		break;
+	case IDMAC_SDC_0:
+	case IDMAC_SDC_1:
+		n_desc = 4;
+	default:
+		break;
+	}
+
+	ipu->channel_init_mask |= 1L << channel;
+
+	/* Enable IPU sub module */
+	ipu_conf = idmac_read_ipureg(ipu, IPU_CONF) |
+		ipu_channel_conf_mask(channel);
+	idmac_write_ipureg(ipu, ipu_conf, IPU_CONF);
+
+	spin_unlock_irqrestore(&ipu->lock, flags);
+
+	if (n_desc && !ichan->desc)
+		ret = idmac_desc_alloc(ichan, n_desc);
+
+	dump_idmac_reg(ipu);
+
+	return ret;
+}
+
+/**
+ * ipu_uninit_channel() - uninitialize an IPU channel.
+ * @idmac:	IPU DMAC context.
+ * @ichan:	pointer to the channel object.
+ */
+static void ipu_uninit_channel(struct idmac *idmac, struct idmac_channel *ichan)
+{
+	enum ipu_channel channel = ichan->dma_chan.chan_id;
+	unsigned long flags;
+	uint32_t reg;
+	unsigned long chan_mask = 1UL << channel;
+	uint32_t ipu_conf;
+	struct ipu *ipu = to_ipu(idmac);
+
+	spin_lock_irqsave(&ipu->lock, flags);
+
+	if (!(ipu->channel_init_mask & chan_mask)) {
+		dev_err(ipu->dev, "Channel already uninitialized %d\n",
+			channel);
+		spin_unlock_irqrestore(&ipu->lock, flags);
+		return;
+	}
+
+	/* Reset the double buffer */
+	reg = idmac_read_ipureg(ipu, IPU_CHA_DB_MODE_SEL);
+	idmac_write_ipureg(ipu, reg & ~chan_mask, IPU_CHA_DB_MODE_SEL);
+
+	ichan->sec_chan_en = false;
+
+	switch (channel) {
+	case IDMAC_IC_7:
+		reg = idmac_read_icreg(ipu, IC_CONF);
+		idmac_write_icreg(ipu, reg & ~(IC_CONF_RWS_EN | IC_CONF_PRPENC_EN),
+			     IC_CONF);
+		break;
+	case IDMAC_IC_0:
+		reg = idmac_read_icreg(ipu, IC_CONF);
+		idmac_write_icreg(ipu, reg & ~(IC_CONF_PRPENC_EN | IC_CONF_PRPENC_CSC1),
+				  IC_CONF);
+		break;
+	case IDMAC_SDC_0:
+	case IDMAC_SDC_1:
+	default:
+		break;
+	}
+
+	ipu->channel_init_mask &= ~(1L << channel);
+
+	ipu_conf = idmac_read_ipureg(ipu, IPU_CONF) &
+		~ipu_channel_conf_mask(channel);
+	idmac_write_ipureg(ipu, ipu_conf, IPU_CONF);
+
+	spin_unlock_irqrestore(&ipu->lock, flags);
+
+	ichan->n_tx_desc = 0;
+	vfree(ichan->desc);
+	ichan->desc = NULL;
+}
+
+/**
+ * ipu_disable_channel() - disable an IPU channel.
+ * @idmac:		IPU DMAC context.
+ * @ichan:		channel object pointer.
+ * @wait_for_stop:	flag to set whether to wait for channel end of frame or
+ *			return immediately.
+ * @return:		0 on success or negative error code on failure.
+ */
+static int ipu_disable_channel(struct idmac *idmac, struct idmac_channel *ichan,
+			       bool wait_for_stop)
+{
+	enum ipu_channel channel = ichan->dma_chan.chan_id;
+	struct ipu *ipu = to_ipu(idmac);
+	uint32_t reg;
+	unsigned long flags;
+	unsigned long chan_mask = 1UL << channel;
+	unsigned int timeout;
+
+	if (wait_for_stop && channel != IDMAC_SDC_1 && channel != IDMAC_SDC_0) {
+		timeout = 40;
+		/* This waiting always fails. Related to spurious irq problem */
+		while ((idmac_read_icreg(ipu, IDMAC_CHA_BUSY) & chan_mask) ||
+		       (ipu_channel_status(ipu, channel) == TASK_STAT_ACTIVE)) {
+			timeout--;
+			msleep(10);
+
+			if (!timeout) {
+				dev_dbg(ipu->dev,
+					"Warning: timeout waiting for channel %u to "
+					"stop: buf0_rdy = 0x%08X, buf1_rdy = 0x%08X, "
+					"busy = 0x%08X, tstat = 0x%08X\n", channel,
+					idmac_read_ipureg(ipu, IPU_CHA_BUF0_RDY),
+					idmac_read_ipureg(ipu, IPU_CHA_BUF1_RDY),
+					idmac_read_icreg(ipu, IDMAC_CHA_BUSY),
+					idmac_read_ipureg(ipu, IPU_TASKS_STAT));
+				break;
+			}
+		}
+		dev_dbg(ipu->dev, "timeout = %d * 10ms\n", 40 - timeout);
+	}
+	/* SDC BG and FG must be disabled before DMA is disabled */
+	if (wait_for_stop && (channel == IDMAC_SDC_0 ||
+			      channel == IDMAC_SDC_1)) {
+		for (timeout = 5;
+		     timeout && !ipu_irq_status(ichan->eof_irq); timeout--)
+			msleep(5);
+	}
+
+	spin_lock_irqsave(&ipu->lock, flags);
+
+	/* Disable IC task */
+	ipu_ic_disable_task(ipu, channel);
+
+	/* Disable DMA channel(s) */
+	reg = idmac_read_icreg(ipu, IDMAC_CHA_EN);
+	idmac_write_icreg(ipu, reg & ~chan_mask, IDMAC_CHA_EN);
+
+	spin_unlock_irqrestore(&ipu->lock, flags);
+
+	return 0;
+}
+
+static struct scatterlist *idmac_sg_next(struct idmac_channel *ichan,
+	struct idmac_tx_desc **desc, struct scatterlist *sg)
+{
+	struct scatterlist *sgnew = sg ? sg_next(sg) : NULL;
+
+	if (sgnew)
+		/* next sg-element in this list */
+		return sgnew;
+
+	if ((*desc)->list.next == &ichan->queue)
+		/* No more descriptors on the queue */
+		return NULL;
+
+	/* Fetch next descriptor */
+	*desc = list_entry((*desc)->list.next, struct idmac_tx_desc, list);
+	return (*desc)->sg;
+}
+
+/*
+ * We have several possibilities here:
+ * current BUF		next BUF
+ *
+ * not last sg		next not last sg
+ * not last sg		next last sg
+ * last sg		first sg from next descriptor
+ * last sg		NULL
+ *
+ * Besides, the descriptor queue might be empty or not. We process all these
+ * cases carefully.
+ */
+static irqreturn_t idmac_interrupt(int irq, void *dev_id)
+{
+	struct idmac_channel *ichan = dev_id;
+	struct device *dev = &ichan->dma_chan.dev->device;
+	unsigned int chan_id = ichan->dma_chan.chan_id;
+	struct scatterlist **sg, *sgnext, *sgnew = NULL;
+	/* Next transfer descriptor */
+	struct idmac_tx_desc *desc, *descnew;
+	bool done = false;
+	u32 ready0, ready1, curbuf, err;
+	unsigned long flags;
+	struct dmaengine_desc_callback cb;
+
+	/* IDMAC has cleared the respective BUFx_RDY bit, we manage the buffer */
+
+	dev_dbg(dev, "IDMAC irq %d, buf %d\n", irq, ichan->active_buffer);
+
+	spin_lock_irqsave(&ipu_data.lock, flags);
+
+	ready0	= idmac_read_ipureg(&ipu_data, IPU_CHA_BUF0_RDY);
+	ready1	= idmac_read_ipureg(&ipu_data, IPU_CHA_BUF1_RDY);
+	curbuf	= idmac_read_ipureg(&ipu_data, IPU_CHA_CUR_BUF);
+	err	= idmac_read_ipureg(&ipu_data, IPU_INT_STAT_4);
+
+	if (err & (1 << chan_id)) {
+		idmac_write_ipureg(&ipu_data, 1 << chan_id, IPU_INT_STAT_4);
+		spin_unlock_irqrestore(&ipu_data.lock, flags);
+		/*
+		 * Doing this
+		 * ichan->sg[0] = ichan->sg[1] = NULL;
+		 * you can force channel re-enable on the next tx_submit(), but
+		 * this is dirty - think about descriptors with multiple
+		 * sg elements.
+		 */
+		dev_warn(dev, "NFB4EOF on channel %d, ready %x, %x, cur %x\n",
+			 chan_id, ready0, ready1, curbuf);
+		return IRQ_HANDLED;
+	}
+	spin_unlock_irqrestore(&ipu_data.lock, flags);
+
+	/* Other interrupts do not interfere with this channel */
+	spin_lock(&ichan->lock);
+	if (unlikely((ichan->active_buffer && (ready1 >> chan_id) & 1) ||
+		     (!ichan->active_buffer && (ready0 >> chan_id) & 1)
+		     )) {
+		spin_unlock(&ichan->lock);
+		dev_dbg(dev,
+			"IRQ with active buffer still ready on channel %x, "
+			"active %d, ready %x, %x!\n", chan_id,
+			ichan->active_buffer, ready0, ready1);
+		return IRQ_NONE;
+	}
+
+	if (unlikely(list_empty(&ichan->queue))) {
+		ichan->sg[ichan->active_buffer] = NULL;
+		spin_unlock(&ichan->lock);
+		dev_err(dev,
+			"IRQ without queued buffers on channel %x, active %d, "
+			"ready %x, %x!\n", chan_id,
+			ichan->active_buffer, ready0, ready1);
+		return IRQ_NONE;
+	}
+
+	/*
+	 * active_buffer is a software flag, it shows which buffer we are
+	 * currently expecting back from the hardware, IDMAC should be
+	 * processing the other buffer already
+	 */
+	sg = &ichan->sg[ichan->active_buffer];
+	sgnext = ichan->sg[!ichan->active_buffer];
+
+	if (!*sg) {
+		spin_unlock(&ichan->lock);
+		return IRQ_HANDLED;
+	}
+
+	desc = list_entry(ichan->queue.next, struct idmac_tx_desc, list);
+	descnew = desc;
+
+	dev_dbg(dev, "IDMAC irq %d, dma %#llx, next dma %#llx, current %d, curbuf %#x\n",
+		irq, (u64)sg_dma_address(*sg),
+		sgnext ? (u64)sg_dma_address(sgnext) : 0,
+		ichan->active_buffer, curbuf);
+
+	/* Find the descriptor of sgnext */
+	sgnew = idmac_sg_next(ichan, &descnew, *sg);
+	if (sgnext != sgnew)
+		dev_err(dev, "Submitted buffer %p, next buffer %p\n", sgnext, sgnew);
+
+	/*
+	 * if sgnext == NULL sg must be the last element in a scatterlist and
+	 * queue must be empty
+	 */
+	if (unlikely(!sgnext)) {
+		if (!WARN_ON(sg_next(*sg)))
+			dev_dbg(dev, "Underrun on channel %x\n", chan_id);
+		ichan->sg[!ichan->active_buffer] = sgnew;
+
+		if (unlikely(sgnew)) {
+			ipu_submit_buffer(ichan, descnew, sgnew, !ichan->active_buffer);
+		} else {
+			spin_lock_irqsave(&ipu_data.lock, flags);
+			ipu_ic_disable_task(&ipu_data, chan_id);
+			spin_unlock_irqrestore(&ipu_data.lock, flags);
+			ichan->status = IPU_CHANNEL_READY;
+			/* Continue to check for complete descriptor */
+		}
+	}
+
+	/* Calculate and submit the next sg element */
+	sgnew = idmac_sg_next(ichan, &descnew, sgnew);
+
+	if (unlikely(!sg_next(*sg)) || !sgnext) {
+		/*
+		 * Last element in scatterlist done, remove from the queue,
+		 * _init for debugging
+		 */
+		list_del_init(&desc->list);
+		done = true;
+	}
+
+	*sg = sgnew;
+
+	if (likely(sgnew) &&
+	    ipu_submit_buffer(ichan, descnew, sgnew, ichan->active_buffer) < 0) {
+		dmaengine_desc_get_callback(&descnew->txd, &cb);
+
+		list_del_init(&descnew->list);
+		spin_unlock(&ichan->lock);
+
+		dmaengine_desc_callback_invoke(&cb, NULL);
+		spin_lock(&ichan->lock);
+	}
+
+	/* Flip the active buffer - even if update above failed */
+	ichan->active_buffer = !ichan->active_buffer;
+	if (done)
+		dma_cookie_complete(&desc->txd);
+
+	dmaengine_desc_get_callback(&desc->txd, &cb);
+
+	spin_unlock(&ichan->lock);
+
+	if (done && (desc->txd.flags & DMA_PREP_INTERRUPT))
+		dmaengine_desc_callback_invoke(&cb, NULL);
+
+	return IRQ_HANDLED;
+}
+
+static void ipu_gc_tasklet(unsigned long arg)
+{
+	struct ipu *ipu = (struct ipu *)arg;
+	int i;
+
+	for (i = 0; i < IPU_CHANNELS_NUM; i++) {
+		struct idmac_channel *ichan = ipu->channel + i;
+		struct idmac_tx_desc *desc;
+		unsigned long flags;
+		struct scatterlist *sg;
+		int j, k;
+
+		for (j = 0; j < ichan->n_tx_desc; j++) {
+			desc = ichan->desc + j;
+			spin_lock_irqsave(&ichan->lock, flags);
+			if (async_tx_test_ack(&desc->txd)) {
+				list_move(&desc->list, &ichan->free_list);
+				for_each_sg(desc->sg, sg, desc->sg_len, k) {
+					if (ichan->sg[0] == sg)
+						ichan->sg[0] = NULL;
+					else if (ichan->sg[1] == sg)
+						ichan->sg[1] = NULL;
+				}
+				async_tx_clear_ack(&desc->txd);
+			}
+			spin_unlock_irqrestore(&ichan->lock, flags);
+		}
+	}
+}
+
+/* Allocate and initialise a transfer descriptor. */
+static struct dma_async_tx_descriptor *idmac_prep_slave_sg(struct dma_chan *chan,
+		struct scatterlist *sgl, unsigned int sg_len,
+		enum dma_transfer_direction direction, unsigned long tx_flags,
+		void *context)
+{
+	struct idmac_channel *ichan = to_idmac_chan(chan);
+	struct idmac_tx_desc *desc = NULL;
+	struct dma_async_tx_descriptor *txd = NULL;
+	unsigned long flags;
+
+	/* We only can handle these three channels so far */
+	if (chan->chan_id != IDMAC_SDC_0 && chan->chan_id != IDMAC_SDC_1 &&
+	    chan->chan_id != IDMAC_IC_7)
+		return NULL;
+
+	if (!is_slave_direction(direction)) {
+		dev_err(chan->device->dev, "Invalid DMA direction %d!\n", direction);
+		return NULL;
+	}
+
+	mutex_lock(&ichan->chan_mutex);
+
+	spin_lock_irqsave(&ichan->lock, flags);
+	if (!list_empty(&ichan->free_list)) {
+		desc = list_entry(ichan->free_list.next,
+				  struct idmac_tx_desc, list);
+
+		list_del_init(&desc->list);
+
+		desc->sg_len	= sg_len;
+		desc->sg	= sgl;
+		txd		= &desc->txd;
+		txd->flags	= tx_flags;
+	}
+	spin_unlock_irqrestore(&ichan->lock, flags);
+
+	mutex_unlock(&ichan->chan_mutex);
+
+	tasklet_schedule(&to_ipu(to_idmac(chan->device))->tasklet);
+
+	return txd;
+}
+
+/* Re-select the current buffer and re-activate the channel */
+static void idmac_issue_pending(struct dma_chan *chan)
+{
+	struct idmac_channel *ichan = to_idmac_chan(chan);
+	struct idmac *idmac = to_idmac(chan->device);
+	struct ipu *ipu = to_ipu(idmac);
+	unsigned long flags;
+
+	/* This is not always needed, but doesn't hurt either */
+	spin_lock_irqsave(&ipu->lock, flags);
+	ipu_select_buffer(chan->chan_id, ichan->active_buffer);
+	spin_unlock_irqrestore(&ipu->lock, flags);
+
+	/*
+	 * Might need to perform some parts of initialisation from
+	 * ipu_enable_channel(), but not all, we do not want to reset to buffer
+	 * 0, don't need to set priority again either, but re-enabling the task
+	 * and the channel might be a good idea.
+	 */
+}
+
+static int idmac_pause(struct dma_chan *chan)
+{
+	struct idmac_channel *ichan = to_idmac_chan(chan);
+	struct idmac *idmac = to_idmac(chan->device);
+	struct ipu *ipu = to_ipu(idmac);
+	struct list_head *list, *tmp;
+	unsigned long flags;
+
+	mutex_lock(&ichan->chan_mutex);
+
+	spin_lock_irqsave(&ipu->lock, flags);
+	ipu_ic_disable_task(ipu, chan->chan_id);
+
+	/* Return all descriptors into "prepared" state */
+	list_for_each_safe(list, tmp, &ichan->queue)
+		list_del_init(list);
+
+	ichan->sg[0] = NULL;
+	ichan->sg[1] = NULL;
+
+	spin_unlock_irqrestore(&ipu->lock, flags);
+
+	ichan->status = IPU_CHANNEL_INITIALIZED;
+
+	mutex_unlock(&ichan->chan_mutex);
+
+	return 0;
+}
+
+static int __idmac_terminate_all(struct dma_chan *chan)
+{
+	struct idmac_channel *ichan = to_idmac_chan(chan);
+	struct idmac *idmac = to_idmac(chan->device);
+	struct ipu *ipu = to_ipu(idmac);
+	unsigned long flags;
+	int i;
+
+	ipu_disable_channel(idmac, ichan,
+			    ichan->status >= IPU_CHANNEL_ENABLED);
+
+	tasklet_disable(&ipu->tasklet);
+
+	/* ichan->queue is modified in ISR, have to spinlock */
+	spin_lock_irqsave(&ichan->lock, flags);
+	list_splice_init(&ichan->queue, &ichan->free_list);
+
+	if (ichan->desc)
+		for (i = 0; i < ichan->n_tx_desc; i++) {
+			struct idmac_tx_desc *desc = ichan->desc + i;
+			if (list_empty(&desc->list))
+				/* Descriptor was prepared, but not submitted */
+				list_add(&desc->list, &ichan->free_list);
+
+			async_tx_clear_ack(&desc->txd);
+		}
+
+	ichan->sg[0] = NULL;
+	ichan->sg[1] = NULL;
+	spin_unlock_irqrestore(&ichan->lock, flags);
+
+	tasklet_enable(&ipu->tasklet);
+
+	ichan->status = IPU_CHANNEL_INITIALIZED;
+
+	return 0;
+}
+
+static int idmac_terminate_all(struct dma_chan *chan)
+{
+	struct idmac_channel *ichan = to_idmac_chan(chan);
+	int ret;
+
+	mutex_lock(&ichan->chan_mutex);
+
+	ret = __idmac_terminate_all(chan);
+
+	mutex_unlock(&ichan->chan_mutex);
+
+	return ret;
+}
+
+#ifdef DEBUG
+static irqreturn_t ic_sof_irq(int irq, void *dev_id)
+{
+	struct idmac_channel *ichan = dev_id;
+	printk(KERN_DEBUG "Got SOF IRQ %d on Channel %d\n",
+	       irq, ichan->dma_chan.chan_id);
+	disable_irq_nosync(irq);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t ic_eof_irq(int irq, void *dev_id)
+{
+	struct idmac_channel *ichan = dev_id;
+	printk(KERN_DEBUG "Got EOF IRQ %d on Channel %d\n",
+	       irq, ichan->dma_chan.chan_id);
+	disable_irq_nosync(irq);
+	return IRQ_HANDLED;
+}
+
+static int ic_sof = -EINVAL, ic_eof = -EINVAL;
+#endif
+
+static int idmac_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct idmac_channel *ichan = to_idmac_chan(chan);
+	struct idmac *idmac = to_idmac(chan->device);
+	int ret;
+
+	/* dmaengine.c now guarantees to only offer free channels */
+	BUG_ON(chan->client_count > 1);
+	WARN_ON(ichan->status != IPU_CHANNEL_FREE);
+
+	dma_cookie_init(chan);
+
+	ret = ipu_irq_map(chan->chan_id);
+	if (ret < 0)
+		goto eimap;
+
+	ichan->eof_irq = ret;
+
+	/*
+	 * Important to first disable the channel, because maybe someone
+	 * used it before us, e.g., the bootloader
+	 */
+	ipu_disable_channel(idmac, ichan, true);
+
+	ret = ipu_init_channel(idmac, ichan);
+	if (ret < 0)
+		goto eichan;
+
+	ret = request_irq(ichan->eof_irq, idmac_interrupt, 0,
+			  ichan->eof_name, ichan);
+	if (ret < 0)
+		goto erirq;
+
+#ifdef DEBUG
+	if (chan->chan_id == IDMAC_IC_7) {
+		ic_sof = ipu_irq_map(69);
+		if (ic_sof > 0) {
+			ret = request_irq(ic_sof, ic_sof_irq, 0, "IC SOF", ichan);
+			if (ret)
+				dev_err(&chan->dev->device, "request irq failed for IC SOF");
+		}
+		ic_eof = ipu_irq_map(70);
+		if (ic_eof > 0) {
+			ret = request_irq(ic_eof, ic_eof_irq, 0, "IC EOF", ichan);
+			if (ret)
+				dev_err(&chan->dev->device, "request irq failed for IC EOF");
+		}
+	}
+#endif
+
+	ichan->status = IPU_CHANNEL_INITIALIZED;
+
+	dev_dbg(&chan->dev->device, "Found channel 0x%x, irq %d\n",
+		chan->chan_id, ichan->eof_irq);
+
+	return ret;
+
+erirq:
+	ipu_uninit_channel(idmac, ichan);
+eichan:
+	ipu_irq_unmap(chan->chan_id);
+eimap:
+	return ret;
+}
+
+static void idmac_free_chan_resources(struct dma_chan *chan)
+{
+	struct idmac_channel *ichan = to_idmac_chan(chan);
+	struct idmac *idmac = to_idmac(chan->device);
+
+	mutex_lock(&ichan->chan_mutex);
+
+	__idmac_terminate_all(chan);
+
+	if (ichan->status > IPU_CHANNEL_FREE) {
+#ifdef DEBUG
+		if (chan->chan_id == IDMAC_IC_7) {
+			if (ic_sof > 0) {
+				free_irq(ic_sof, ichan);
+				ipu_irq_unmap(69);
+				ic_sof = -EINVAL;
+			}
+			if (ic_eof > 0) {
+				free_irq(ic_eof, ichan);
+				ipu_irq_unmap(70);
+				ic_eof = -EINVAL;
+			}
+		}
+#endif
+		free_irq(ichan->eof_irq, ichan);
+		ipu_irq_unmap(chan->chan_id);
+	}
+
+	ichan->status = IPU_CHANNEL_FREE;
+
+	ipu_uninit_channel(idmac, ichan);
+
+	mutex_unlock(&ichan->chan_mutex);
+
+	tasklet_schedule(&to_ipu(idmac)->tasklet);
+}
+
+static enum dma_status idmac_tx_status(struct dma_chan *chan,
+		       dma_cookie_t cookie, struct dma_tx_state *txstate)
+{
+	return dma_cookie_status(chan, cookie, txstate);
+}
+
+static int __init ipu_idmac_init(struct ipu *ipu)
+{
+	struct idmac *idmac = &ipu->idmac;
+	struct dma_device *dma = &idmac->dma;
+	int i;
+
+	dma_cap_set(DMA_SLAVE, dma->cap_mask);
+	dma_cap_set(DMA_PRIVATE, dma->cap_mask);
+
+	/* Compulsory common fields */
+	dma->dev				= ipu->dev;
+	dma->device_alloc_chan_resources	= idmac_alloc_chan_resources;
+	dma->device_free_chan_resources		= idmac_free_chan_resources;
+	dma->device_tx_status			= idmac_tx_status;
+	dma->device_issue_pending		= idmac_issue_pending;
+
+	/* Compulsory for DMA_SLAVE fields */
+	dma->device_prep_slave_sg		= idmac_prep_slave_sg;
+	dma->device_pause			= idmac_pause;
+	dma->device_terminate_all		= idmac_terminate_all;
+
+	INIT_LIST_HEAD(&dma->channels);
+	for (i = 0; i < IPU_CHANNELS_NUM; i++) {
+		struct idmac_channel *ichan = ipu->channel + i;
+		struct dma_chan *dma_chan = &ichan->dma_chan;
+
+		spin_lock_init(&ichan->lock);
+		mutex_init(&ichan->chan_mutex);
+
+		ichan->status		= IPU_CHANNEL_FREE;
+		ichan->sec_chan_en	= false;
+		snprintf(ichan->eof_name, sizeof(ichan->eof_name), "IDMAC EOF %d", i);
+
+		dma_chan->device	= &idmac->dma;
+		dma_cookie_init(dma_chan);
+		dma_chan->chan_id	= i;
+		list_add_tail(&dma_chan->device_node, &dma->channels);
+	}
+
+	idmac_write_icreg(ipu, 0x00000070, IDMAC_CONF);
+
+	return dma_async_device_register(&idmac->dma);
+}
+
+static void ipu_idmac_exit(struct ipu *ipu)
+{
+	int i;
+	struct idmac *idmac = &ipu->idmac;
+
+	for (i = 0; i < IPU_CHANNELS_NUM; i++) {
+		struct idmac_channel *ichan = ipu->channel + i;
+
+		idmac_terminate_all(&ichan->dma_chan);
+	}
+
+	dma_async_device_unregister(&idmac->dma);
+}
+
+/*****************************************************************************
+ * IPU common probe / remove
+ */
+
+static int __init ipu_probe(struct platform_device *pdev)
+{
+	struct resource *mem_ipu, *mem_ic;
+	int ret;
+
+	spin_lock_init(&ipu_data.lock);
+
+	mem_ipu	= platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mem_ic	= platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!mem_ipu || !mem_ic)
+		return -EINVAL;
+
+	ipu_data.dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, &ipu_data);
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		goto err_noirq;
+
+	ipu_data.irq_fn = ret;
+	ret = platform_get_irq(pdev, 1);
+	if (ret < 0)
+		goto err_noirq;
+
+	ipu_data.irq_err = ret;
+
+	dev_dbg(&pdev->dev, "fn irq %u, err irq %u\n",
+		ipu_data.irq_fn, ipu_data.irq_err);
+
+	/* Remap IPU common registers */
+	ipu_data.reg_ipu = ioremap(mem_ipu->start, resource_size(mem_ipu));
+	if (!ipu_data.reg_ipu) {
+		ret = -ENOMEM;
+		goto err_ioremap_ipu;
+	}
+
+	/* Remap Image Converter and Image DMA Controller registers */
+	ipu_data.reg_ic = ioremap(mem_ic->start, resource_size(mem_ic));
+	if (!ipu_data.reg_ic) {
+		ret = -ENOMEM;
+		goto err_ioremap_ic;
+	}
+
+	/* Get IPU clock */
+	ipu_data.ipu_clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(ipu_data.ipu_clk)) {
+		ret = PTR_ERR(ipu_data.ipu_clk);
+		goto err_clk_get;
+	}
+
+	/* Make sure IPU HSP clock is running */
+	clk_prepare_enable(ipu_data.ipu_clk);
+
+	/* Disable all interrupts */
+	idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_1);
+	idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_2);
+	idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_3);
+	idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_4);
+	idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_5);
+
+	dev_dbg(&pdev->dev, "%s @ 0x%08lx, fn irq %u, err irq %u\n", pdev->name,
+		(unsigned long)mem_ipu->start, ipu_data.irq_fn, ipu_data.irq_err);
+
+	ret = ipu_irq_attach_irq(&ipu_data, pdev);
+	if (ret < 0)
+		goto err_attach_irq;
+
+	/* Initialize DMA engine */
+	ret = ipu_idmac_init(&ipu_data);
+	if (ret < 0)
+		goto err_idmac_init;
+
+	tasklet_init(&ipu_data.tasklet, ipu_gc_tasklet, (unsigned long)&ipu_data);
+
+	ipu_data.dev = &pdev->dev;
+
+	dev_dbg(ipu_data.dev, "IPU initialized\n");
+
+	return 0;
+
+err_idmac_init:
+err_attach_irq:
+	ipu_irq_detach_irq(&ipu_data, pdev);
+	clk_disable_unprepare(ipu_data.ipu_clk);
+	clk_put(ipu_data.ipu_clk);
+err_clk_get:
+	iounmap(ipu_data.reg_ic);
+err_ioremap_ic:
+	iounmap(ipu_data.reg_ipu);
+err_ioremap_ipu:
+err_noirq:
+	dev_err(&pdev->dev, "Failed to probe IPU: %d\n", ret);
+	return ret;
+}
+
+static int ipu_remove(struct platform_device *pdev)
+{
+	struct ipu *ipu = platform_get_drvdata(pdev);
+
+	ipu_idmac_exit(ipu);
+	ipu_irq_detach_irq(ipu, pdev);
+	clk_disable_unprepare(ipu->ipu_clk);
+	clk_put(ipu->ipu_clk);
+	iounmap(ipu->reg_ic);
+	iounmap(ipu->reg_ipu);
+	tasklet_kill(&ipu->tasklet);
+
+	return 0;
+}
+
+/*
+ * We need two MEM resources - with IPU-common and Image Converter registers,
+ * including PF_CONF and IDMAC_* registers, and two IRQs - function and error
+ */
+static struct platform_driver ipu_platform_driver = {
+	.driver = {
+		.name	= "ipu-core",
+	},
+	.remove		= ipu_remove,
+};
+
+static int __init ipu_init(void)
+{
+	return platform_driver_probe(&ipu_platform_driver, ipu_probe);
+}
+subsys_initcall(ipu_init);
+
+MODULE_DESCRIPTION("IPU core driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
+MODULE_ALIAS("platform:ipu-core");