ENGR00127167: Add gpmi nfc and apbh dma support for mx50.

Add gpmi nfc and apbh dma support for mx50.

Signed-off-by: Terry Lv <r65388@freescale.com>

1 files changed, 825 insertions, 0 deletions

diff --git a/drivers/dma/apbh_dma.c b/drivers/dma/apbh_dma.c
new file mode 100644
index 0000000..296125a
--- /dev/null
+++ b/drivers/dma/apbh_dma.c
@@ -0,0 +1,825 @@
+/*
+ * Copyright (C) 2010 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 as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <asm/apbh_dma.h>
+
+#include <linux/err.h>
+#include <linux/list.h>
+#include <malloc.h>
+#include <common.h>
+#include <asm/io.h>
+
+#ifdef CONFIG_ARCH_MMU
+#include <asm/arch/mmu.h>
+#endif
+
+#ifndef BM_APBH_CTRL0_APB_BURST_EN
+#define BM_APBH_CTRL0_APB_BURST_EN BM_APBH_CTRL0_APB_BURST4_EN
+#endif
+
+#if 0
+static inline s32 mxs_dma_apbh_reset_block(void *hwreg, int is_enable)
+{
+	int timeout;
+
+	/* the process of software reset of IP block is done
+	   in several steps:
+
+	   - clear SFTRST and wait for block is enabled;
+	   - clear clock gating (CLKGATE bit);
+	   - set the SFTRST again and wait for block is in reset;
+	   - clear SFTRST and wait for reset completion.
+	 */
+	/* clear SFTRST */
+	REG_CLR_ADDR(hwreg, BM_APBH_CTRL0_SFTRST);
+
+	for (timeout = 1000000; timeout > 0; timeout--)
+		/* still in SFTRST state ? */
+		if ((REG_RD_ADDR(hwreg) & BM_APBH_CTRL0_SFTRST) == 0)
+			break;
+		if (timeout <= 0) {
+			printk(KERN_ERR "%s(%p): timeout when enabling\n",
+				__func__, hwreg);
+			return -ETIME;
+	}
+
+	/* clear CLKGATE */
+	REG_CLR_ADDR(hwreg, BM_APBH_CTRL0_CLKGATE);
+
+	if (is_enable) {
+		/* now again set SFTRST */
+		REG_SET_ADDR(hwreg, BM_APBH_CTRL0_SFTRST);
+		for (timeout = 1000000; timeout > 0; timeout--)
+			/* poll until CLKGATE set */
+			if (REG_RD_ADDR(hwreg) & BM_APBH_CTRL0_CLKGATE)
+				break;
+		if (timeout <= 0) {
+			printk(KERN_ERR "%s(%p): timeout when resetting\n",
+				__func__, hwreg);
+			return -ETIME;
+		}
+
+		REG_CLR_ADDR(hwreg, BM_APBH_CTRL0_SFTRST);
+		for (timeout = 1000000; timeout > 0; timeout--)
+			/* still in SFTRST state ? */
+			if ((REG_RD_ADDR(hwreg) & BM_APBH_CTRL0_SFTRST) == 0)
+				break;
+		if (timeout <= 0) {
+			printk(KERN_ERR "%s(%p): timeout when enabling "
+				"after reset\n", __func__, hwreg);
+			return -ETIME;
+		}
+
+		/* clear CLKGATE */
+		REG_CLR_ADDR(hwreg, BM_APBH_CTRL0_CLKGATE);
+	}
+	for (timeout = 1000000; timeout > 0; timeout--)
+		/* still in SFTRST state ? */
+		if ((REG_RD_ADDR(hwreg) & BM_APBH_CTRL0_CLKGATE) == 0)
+			break;
+
+	if (timeout <= 0) {
+		printk(KERN_ERR "%s(%p): timeout when unclockgating\n",
+			__func__, hwreg);
+		return -ETIME;
+	}
+
+	return 0;
+}
+#endif
+
+static int mxs_dma_apbh_enable(struct mxs_dma_chan *pchan, unsigned int chan)
+{
+	unsigned int sem;
+	struct mxs_dma_device *pdev = pchan->dma;
+	struct mxs_dma_desc *pdesc;
+
+	pdesc = list_first_entry(&pchan->active, struct mxs_dma_desc, node);
+	if (pdesc == NULL)
+		return -EFAULT;
+
+	sem = readl(pdev->base + HW_APBH_CHn_SEMA(chan));
+	sem = (sem & BM_APBH_CHn_SEMA_PHORE) >> BP_APBH_CHn_SEMA_PHORE;
+	if (pchan->flags & MXS_DMA_FLAGS_BUSY) {
+		if (pdesc->cmd.cmd.bits.chain == 0)
+			return 0;
+		if (sem < 2) {
+			if (!sem)
+				return 0;
+			pdesc = list_entry(pdesc->node.next,
+					   struct mxs_dma_desc, node);
+#ifdef CONFIG_ARCH_MMU
+			writel(iomem_to_phys(mxs_dma_cmd_address(pdesc)),
+				     pdev->base + HW_APBH_CHn_NXTCMDAR(chan));
+#else
+			writel(mxs_dma_cmd_address(pdesc),
+				     pdev->base + HW_APBH_CHn_NXTCMDAR(chan));
+#endif
+		}
+		sem = pchan->pending_num;
+		pchan->pending_num = 0;
+		writel(BF_APBH_CHn_SEMA_INCREMENT_SEMA(sem),
+			     pdev->base + HW_APBH_CHn_SEMA(chan));
+		pchan->active_num += sem;
+		return 0;
+	}
+
+	pchan->active_num += pchan->pending_num;
+	pchan->pending_num = 0;
+#ifdef CONFIG_ARCH_MMU
+	writel(iomem_to_phys(mxs_dma_cmd_address(pdesc)),
+	     pdev->base + HW_APBH_CHn_NXTCMDAR(chan));
+#else
+	writel(mxs_dma_cmd_address(pdesc),
+	     pdev->base + HW_APBH_CHn_NXTCMDAR(chan));
+#endif
+	writel(pchan->active_num, pdev->base + HW_APBH_CHn_SEMA(chan));
+	REG_CLR(pdev->base, HW_APBH_CTRL0, 1 << chan);
+	return 0;
+}
+
+static void mxs_dma_apbh_disable(struct mxs_dma_chan *pchan, unsigned int chan)
+{
+	struct mxs_dma_device *pdev = pchan->dma;
+
+	REG_SET(pdev->base, HW_APBH_CTRL0,
+		1 << (chan + BP_APBH_CTRL0_CLKGATE_CHANNEL));
+}
+
+static void mxs_dma_apbh_reset(struct mxs_dma_device *pdev, unsigned int chan)
+{
+	REG_SET(pdev->base, HW_APBH_CHANNEL_CTRL,
+		1 << (chan + BP_APBH_CHANNEL_CTRL_RESET_CHANNEL));
+}
+
+static void mxs_dma_apbh_freeze(struct mxs_dma_device *pdev, unsigned int chan)
+{
+	REG_SET(pdev->base, HW_APBH_CHANNEL_CTRL, 1 << chan);
+}
+
+static void
+mxs_dma_apbh_unfreeze(struct mxs_dma_device *pdev, unsigned int chan)
+{
+	REG_CLR(pdev->base, HW_APBH_CHANNEL_CTRL, 1 << chan);
+}
+
+static void mxs_dma_apbh_info(struct mxs_dma_device *pdev,
+		unsigned int chan, struct mxs_dma_info *info)
+{
+	unsigned int reg;
+
+	reg = REG_RD(pdev->base, HW_APBH_CTRL2);
+	info->status = reg >> chan;
+	info->buf_addr = readl(pdev->base + HW_APBH_CHn_BAR(chan));
+}
+
+static int
+mxs_dma_apbh_read_semaphore(struct mxs_dma_device *pdev, unsigned int chan)
+{
+	unsigned int reg;
+
+	reg = readl(pdev->base + HW_APBH_CHn_SEMA(chan));
+	return (reg & BM_APBH_CHn_SEMA_PHORE) >> BP_APBH_CHn_SEMA_PHORE;
+}
+
+static void
+mxs_dma_apbh_enable_irq(struct mxs_dma_device *pdev,
+			unsigned int chan, int enable)
+{
+	if (enable)
+		REG_SET(pdev->base, HW_APBH_CTRL1, 1 << (chan + 16));
+	else
+		REG_CLR(pdev->base, HW_APBH_CTRL1, 1 << (chan + 16));
+
+}
+
+static int
+mxs_dma_apbh_irq_is_pending(struct mxs_dma_device *pdev, unsigned int chan)
+{
+	unsigned int reg;
+
+	reg = REG_RD(pdev->base, HW_APBH_CTRL1);
+	reg |= REG_RD(pdev->base, HW_APBH_CTRL2);
+
+	return reg & (1 << chan);
+}
+
+static void mxs_dma_apbh_ack_irq(struct mxs_dma_device *pdev,
+				unsigned int chan)
+{
+	REG_CLR(pdev->base, HW_APBH_CTRL1, 1 << chan);
+	REG_CLR(pdev->base, HW_APBH_CTRL2, 1 << chan);
+}
+
+static struct mxs_dma_device mxs_dma_apbh = {
+	.name = "mxs-dma-apbh",
+};
+
+static int mxs_dma_apbh_probe(void)
+{
+	int i = 1000000;
+	u32 base = CONFIG_MXS_DMA_REG_BASE;
+
+	mxs_dma_apbh.base = (void *)base;
+
+	/*
+	mxs_dma_apbh_reset_block((void *)(base + HW_APBH_CTRL0), 1);
+	*/
+	REG_CLR(base, HW_APBH_CTRL0,
+		BM_APBH_CTRL0_SFTRST);
+	for (; i > 0; --i) {
+		if (!(REG_RD(base, HW_APBH_CTRL0) &
+		      BM_APBH_CTRL0_SFTRST))
+			break;
+		udelay(2);
+	}
+	if (i <= 0)
+		return -ETIME;
+	REG_CLR(base, HW_APBH_CTRL0, BM_APBH_CTRL0_CLKGATE);
+
+#ifdef CONFIG_APBH_DMA_BURST8
+	REG_SET(base, HW_APBH_CTRL0,
+		BM_APBH_CTRL0_AHB_BURST8_EN);
+#else
+	REG_CLR(base, HW_APBH_CTRL0,
+		BM_APBH_CTRL0_AHB_BURST8_EN);
+#endif
+
+#ifdef CONFIG_APBH_DMA_BURST
+	REG_SET(base, HW_APBH_CTRL0,
+		BM_APBH_CTRL0_APB_BURST_EN);
+#else
+	REG_CLR(base, HW_APBH_CTRL0,
+		BM_APBH_CTRL0_APB_BURST_EN);
+#endif
+
+	mxs_dma_apbh.chan_base = MXS_DMA_CHANNEL_AHB_APBH_GPMI0;
+	mxs_dma_apbh.chan_num = MXS_MAX_DMA_CHANNELS;
+
+	return mxs_dma_device_register(&mxs_dma_apbh);
+}
+
+/* DMA engine */
+
+/*
+ * The list of DMA drivers that manage various DMA channels. A DMA device
+ * driver registers to manage DMA channels by calling mxs_dma_device_register().
+ */
+static LIST_HEAD(mxs_dma_devices);
+
+/*
+ * The array of struct mxs_dma_chan that represent every DMA channel in the
+ * system. The index of the structure in the array indicates the specific DMA
+ * hardware it represents (see mach-mx28/include/mach/dma.h).
+ */
+
+static struct mxs_dma_chan mxs_dma_channels[MXS_MAX_DMA_CHANNELS];
+
+int mxs_dma_request(int channel)
+{
+	int ret = 0;
+	struct mxs_dma_chan *pchan;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return -EINVAL;
+
+	pchan = mxs_dma_channels + channel;
+	if ((pchan->flags & MXS_DMA_FLAGS_VALID) != MXS_DMA_FLAGS_VALID) {
+		ret = -ENODEV;
+		goto out;
+	}
+	if (pchan->flags & MXS_DMA_FLAGS_ALLOCATED) {
+		ret = -EBUSY;
+		goto out;
+	}
+	pchan->flags |= MXS_DMA_FLAGS_ALLOCATED;
+	pchan->active_num = 0;
+	pchan->pending_num = 0;
+	INIT_LIST_HEAD(&pchan->active);
+	INIT_LIST_HEAD(&pchan->done);
+out:
+	return ret;
+}
+
+void mxs_dma_release(int channel)
+{
+	struct mxs_dma_chan *pchan;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return;
+
+	pchan = mxs_dma_channels + channel;
+
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return;
+
+	if (pchan->flags & MXS_DMA_FLAGS_BUSY)
+		return;
+
+	pchan->dev = 0;
+	pchan->active_num = 0;
+	pchan->pending_num = 0;
+	pchan->flags &= ~MXS_DMA_FLAGS_ALLOCATED;
+}
+
+int mxs_dma_enable(int channel)
+{
+	int ret = 0;
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return -EINVAL;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return -EINVAL;
+
+	pdma = pchan->dma;
+	if (pchan->pending_num)
+		ret = mxs_dma_apbh_enable(pchan, channel - pdma->chan_base);
+	pchan->flags |= MXS_DMA_FLAGS_BUSY;
+	return ret;
+}
+
+void mxs_dma_disable(int channel)
+{
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return;
+	if (!(pchan->flags & MXS_DMA_FLAGS_BUSY))
+		return;
+	pdma = pchan->dma;
+	mxs_dma_apbh_disable(pchan, channel - pdma->chan_base);
+	pchan->flags &= ~MXS_DMA_FLAGS_BUSY;
+	pchan->active_num = 0;
+	pchan->pending_num = 0;
+	list_splice_init(&pchan->active, &pchan->done);
+}
+
+int mxs_dma_get_info(int channel, struct mxs_dma_info *info)
+{
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if (!info)
+		return -EINVAL;
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return -EINVAL;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return -EFAULT;
+	pdma = pchan->dma;
+	mxs_dma_apbh_info(pdma, channel - pdma->chan_base, info);
+
+	return 0;
+}
+
+int mxs_dma_cooked(int channel, struct list_head *head)
+{
+	int sem;
+	struct mxs_dma_chan *pchan;
+	struct list_head *p, *q;
+	struct mxs_dma_desc *pdesc;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return -EINVAL;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return -EINVAL;
+
+	sem = mxs_dma_read_semaphore(channel);
+	if (sem < 0)
+		return sem;
+	if (sem == pchan->active_num)
+		return 0;
+	list_for_each_safe(p, q, &pchan->active) {
+		if ((pchan->active_num) <= sem)
+			break;
+		pdesc = list_entry(p, struct mxs_dma_desc, node);
+		pdesc->flags &= ~MXS_DMA_DESC_READY;
+		if (head)
+			list_move_tail(p, head);
+		else
+			list_move_tail(p, &pchan->done);
+		if (pdesc->flags & MXS_DMA_DESC_LAST)
+			pchan->active_num--;
+	}
+	if (sem == 0)
+		pchan->flags &= ~MXS_DMA_FLAGS_BUSY;
+
+	return 0;
+}
+
+void mxs_dma_reset(int channel)
+{
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return;
+	pdma = pchan->dma;
+	mxs_dma_apbh_reset(pdma, channel - pdma->chan_base);
+}
+
+void mxs_dma_freeze(int channel)
+{
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return;
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return;
+	pdma = pchan->dma;
+	mxs_dma_apbh_freeze(pdma, channel - pdma->chan_base);
+}
+
+void mxs_dma_unfreeze(int channel)
+{
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return;
+	pdma = pchan->dma;
+	mxs_dma_apbh_unfreeze(pdma, channel - pdma->chan_base);
+}
+
+int mxs_dma_read_semaphore(int channel)
+{
+	int ret = -EINVAL;
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return ret;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return ret;
+	pdma = pchan->dma;
+	ret = mxs_dma_apbh_read_semaphore(pdma, channel - pdma->chan_base);
+
+	return ret;
+}
+
+void mxs_dma_enable_irq(int channel, int en)
+{
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return;
+	pdma = pchan->dma;
+	mxs_dma_apbh_enable_irq(pdma, channel - pdma->chan_base, en);
+}
+
+int mxs_dma_irq_is_pending(int channel)
+{
+	int ret = 0;
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return ret;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return ret;
+	pdma = pchan->dma;
+	ret = mxs_dma_apbh_irq_is_pending(pdma, channel - pdma->chan_base);
+
+	return ret;
+}
+
+void mxs_dma_ack_irq(int channel)
+{
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return;
+	pdma = pchan->dma;
+	mxs_dma_apbh_ack_irq(pdma, channel - pdma->chan_base);
+}
+
+/* mxs dma utility function */
+struct mxs_dma_desc *mxs_dma_alloc_desc(void)
+{
+	struct mxs_dma_desc *pdesc;
+#ifdef CONFIG_ARCH_MMU
+	u32 address;
+#endif
+
+#ifdef CONFIG_ARCH_MMU
+	address = (u32)iomem_to_phys((ulong)memalign(MXS_DMA_ALIGNMENT,
+				sizeof(struct mxs_dma_desc)));
+	if (!address)
+		return NULL;
+	pdesc = (struct mxs_dma_desc *)ioremap_nocache(address,
+		MXS_DMA_ALIGNMENT);
+	memset(pdesc, 0, sizeof(*pdesc));
+	pdesc->address = address;
+#else
+	pdesc = (struct mxs_dma_desc *)memalign(MXS_DMA_ALIGNMENT,
+				sizeof(struct mxs_dma_desc));
+	if (pdesc == NULL)
+		return NULL;
+	memset(pdesc, 0, sizeof(*pdesc));
+	pdesc->address = pdesc;
+#endif
+
+	return pdesc;
+};
+
+void mxs_dma_free_desc(struct mxs_dma_desc *pdesc)
+{
+	if (pdesc == NULL)
+		return;
+
+	free(pdesc);
+}
+
+int mxs_dma_desc_append(int channel, struct mxs_dma_desc *pdesc)
+{
+	int ret = 0;
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_desc *last;
+	struct mxs_dma_device *pdma;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return -EINVAL;
+
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return -EINVAL;
+	pdma = pchan->dma;
+#ifdef CONFIG_ARCH_MMU
+	pdesc->cmd.next = iomem_to_phys(mxs_dma_cmd_address(pdesc));
+#else
+	pdesc->cmd.next = mxs_dma_cmd_address(pdesc);
+#endif
+	pdesc->flags |= MXS_DMA_DESC_FIRST | MXS_DMA_DESC_LAST;
+	if (!list_empty(&pchan->active)) {
+
+		last = list_entry(pchan->active.prev,
+				  struct mxs_dma_desc, node);
+
+		pdesc->flags &= ~MXS_DMA_DESC_FIRST;
+		last->flags &= ~MXS_DMA_DESC_LAST;
+
+#ifdef CONFIG_ARCH_MMU
+		last->cmd.next = iomem_to_phys(mxs_dma_cmd_address(pdesc));
+#else
+		last->cmd.next = mxs_dma_cmd_address(pdesc);
+#endif
+		last->cmd.cmd.bits.chain = 1;
+	}
+	pdesc->flags |= MXS_DMA_DESC_READY;
+	if (pdesc->flags & MXS_DMA_DESC_FIRST)
+		pchan->pending_num++;
+	list_add_tail(&pdesc->node, &pchan->active);
+
+	return ret;
+}
+
+int mxs_dma_desc_add_list(int channel, struct list_head *head)
+{
+	int ret = 0, size = 0;
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+	struct list_head *p;
+	struct mxs_dma_desc *prev = NULL, *pcur;
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return -EINVAL;
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return -EINVAL;
+
+	if (list_empty(head))
+		return 0;
+
+	pdma = pchan->dma;
+	list_for_each(p, head) {
+		pcur = list_entry(p, struct mxs_dma_desc, node);
+		if (!(pcur->cmd.cmd.bits.dec_sem || pcur->cmd.cmd.bits.chain))
+			return -EINVAL;
+		if (prev)
+#ifdef CONFIG_ARCH_MMU
+			prev->cmd.next =
+				iomem_to_phys(mxs_dma_cmd_address(pcur));
+#else
+			prev->cmd.next = mxs_dma_cmd_address(pcur);
+#endif
+		else
+			pcur->flags |= MXS_DMA_DESC_FIRST;
+		pcur->flags |= MXS_DMA_DESC_READY;
+		prev = pcur;
+		size++;
+	}
+	pcur = list_first_entry(head, struct mxs_dma_desc, node);
+#ifdef CONFIG_ARCH_MMU
+	prev->cmd.next = iomem_to_phys(mxs_dma_cmd_address(pcur));
+#else
+	prev->cmd.next = mxs_dma_cmd_address(pcur);
+#endif
+	prev->flags |= MXS_DMA_DESC_LAST;
+
+	if (!list_empty(&pchan->active)) {
+		pcur = list_entry(pchan->active.next,
+				  struct mxs_dma_desc, node);
+		if (pcur->cmd.cmd.bits.dec_sem != prev->cmd.cmd.bits.dec_sem) {
+			ret = -EFAULT;
+			goto out ;
+		}
+#ifdef CONFIG_ARCH_MMU
+		prev->cmd.next = iomem_to_phys(mxs_dma_cmd_address(pcur));
+#else
+		prev->cmd.next = mxs_dma_cmd_address(pcur);
+#endif
+		prev = list_entry(pchan->active.prev,
+				  struct mxs_dma_desc, node);
+		pcur = list_first_entry(head, struct mxs_dma_desc, node);
+		pcur->flags &= ~MXS_DMA_DESC_FIRST;
+		prev->flags &= ~MXS_DMA_DESC_LAST;
+#ifdef CONFIG_ARCH_MMU
+		prev->cmd.next = iomem_to_phys(mxs_dma_cmd_address(pcur));
+#else
+		prev->cmd.next = mxs_dma_cmd_address(pcur);
+#endif
+	}
+	list_splice(head, &pchan->active);
+	pchan->pending_num += size;
+	if (!(pcur->cmd.cmd.bits.dec_sem) && (pcur->flags & MXS_DMA_DESC_FIRST))
+		pchan->pending_num += 1;
+	else
+		pchan->pending_num += size;
+
+out:
+	return ret;
+}
+
+int mxs_dma_get_cooked(int channel, struct list_head *head)
+{
+	struct mxs_dma_chan *pchan;
+
+	if ((channel < 0) || (channel >= MXS_MAX_DMA_CHANNELS))
+		return -EINVAL;
+	pchan = mxs_dma_channels + channel;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return -EINVAL;
+
+	if (head == NULL)
+		return 0;
+
+	list_splice(&pchan->done, head);
+
+	return 0;
+}
+
+int mxs_dma_device_register(struct mxs_dma_device *pdev)
+{
+	int i;
+	struct mxs_dma_chan *pchan;
+
+	if (pdev == NULL || !pdev->chan_num)
+		return -EINVAL;
+
+	if ((pdev->chan_base >= MXS_MAX_DMA_CHANNELS) ||
+	    ((pdev->chan_base + pdev->chan_num) > MXS_MAX_DMA_CHANNELS))
+		return -EINVAL;
+
+	pchan = mxs_dma_channels + pdev->chan_base;
+	for (i = 0; i < pdev->chan_num; i++, pchan++) {
+		pchan->dma = pdev;
+		pchan->flags = MXS_DMA_FLAGS_VALID;
+	}
+	list_add(&pdev->node, &mxs_dma_devices);
+
+	return 0;
+}
+
+/* DMA Operation */
+int mxs_dma_init(void)
+{
+	s32 dma_channel = 0, err = 0;
+
+	mxs_dma_apbh_probe();
+
+	for (dma_channel = MXS_DMA_CHANNEL_AHB_APBH_GPMI0;
+		dma_channel <= MXS_DMA_CHANNEL_AHB_APBH_GPMI7;
+		++dma_channel) {
+		err = mxs_dma_request(dma_channel);
+
+		if (err) {
+			printf("Can't acquire DMA channel %u\n", dma_channel);
+
+			/* Free all the channels we've already acquired. */
+			while (--dma_channel >= 0)
+				mxs_dma_release(dma_channel);
+			return err;
+		}
+
+		mxs_dma_reset(dma_channel);
+		mxs_dma_ack_irq(dma_channel);
+	}
+
+	return 0;
+}
+
+int mxs_dma_wait_complete(u32 uSecTimeout, unsigned int chan)
+{
+	struct mxs_dma_chan *pchan;
+	struct mxs_dma_device *pdma;
+
+	if ((chan < 0) || (chan >= MXS_MAX_DMA_CHANNELS))
+		return 1;
+
+	pchan = mxs_dma_channels + chan;
+	if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED))
+		return 1;
+	pdma = pchan->dma;
+
+	while ((!(REG_RD(pdma->base, HW_APBH_CTRL1) & (1 << chan))) &&
+		--uSecTimeout)
+		;
+
+	if (uSecTimeout <= 0) {
+		/* Abort dma by resetting channel */
+		mxs_dma_apbh_reset(pdma, chan - pdma->chan_base);
+		return 1;
+	}
+
+	return 0;
+}
+
+int mxs_dma_go(int chan)
+{
+	u32 timeout = 10000;
+	int  error;
+
+	LIST_HEAD(tmp_desc_list);
+
+	/* Get ready... */
+	mxs_dma_enable_irq(chan, 1);
+
+	/* Go! */
+	mxs_dma_enable(chan);
+
+	/* Wait for it to finish. */
+	error = (mxs_dma_wait_complete(timeout, chan)) ? -ETIMEDOUT : 0;
+
+	/* Clear out the descriptors we just ran. */
+	mxs_dma_cooked(chan, &tmp_desc_list);
+
+	/* Shut the DMA channel down. */
+	/* Clear irq */
+	mxs_dma_ack_irq(chan);
+	mxs_dma_reset(chan);
+	mxs_dma_enable_irq(chan, 0);
+	mxs_dma_disable(chan);
+
+	/* Return. */
+	return error;
+}
+