Merge branch 'master' into for-next

1 files changed, 862 insertions, 0 deletions

diff --git a/arch/arm/mach-imx/dma-v1.c b/arch/arm/mach-imx/dma-v1.c
new file mode 100644
index 000000000000..3e8c47c63bac
--- /dev/null
+++ b/arch/arm/mach-imx/dma-v1.c
@@ -0,0 +1,862 @@
+/*
+ *  linux/arch/arm/plat-mxc/dma-v1.c
+ *
+ *  i.MX DMA registration and IRQ dispatching
+ *
+ * Copyright 2006 Pavel Pisa <pisa@cmp.felk.cvut.cz>
+ * Copyright 2008 Juergen Beisert, <kernel@pengutronix.de>
+ * Copyright 2008 Sascha Hauer, <s.hauer@pengutronix.de>
+ *
+ * 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 <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/errno.h>
+#include <linux/clk.h>
+#include <linux/scatterlist.h>
+#include <linux/io.h>
+
+#include <asm/system.h>
+#include <asm/irq.h>
+#include <mach/hardware.h>
+#include <mach/dma-v1.h>
+
+#define DMA_DCR     0x00		/* Control Register */
+#define DMA_DISR    0x04		/* Interrupt status Register */
+#define DMA_DIMR    0x08		/* Interrupt mask Register */
+#define DMA_DBTOSR  0x0c		/* Burst timeout status Register */
+#define DMA_DRTOSR  0x10		/* Request timeout Register */
+#define DMA_DSESR   0x14		/* Transfer Error Status Register */
+#define DMA_DBOSR   0x18		/* Buffer overflow status Register */
+#define DMA_DBTOCR  0x1c		/* Burst timeout control Register */
+#define DMA_WSRA    0x40		/* W-Size Register A */
+#define DMA_XSRA    0x44		/* X-Size Register A */
+#define DMA_YSRA    0x48		/* Y-Size Register A */
+#define DMA_WSRB    0x4c		/* W-Size Register B */
+#define DMA_XSRB    0x50		/* X-Size Register B */
+#define DMA_YSRB    0x54		/* Y-Size Register B */
+#define DMA_SAR(x)  (0x80 + ((x) << 6))	/* Source Address Registers */
+#define DMA_DAR(x)  (0x84 + ((x) << 6))	/* Destination Address Registers */
+#define DMA_CNTR(x) (0x88 + ((x) << 6))	/* Count Registers */
+#define DMA_CCR(x)  (0x8c + ((x) << 6))	/* Control Registers */
+#define DMA_RSSR(x) (0x90 + ((x) << 6))	/* Request source select Registers */
+#define DMA_BLR(x)  (0x94 + ((x) << 6))	/* Burst length Registers */
+#define DMA_RTOR(x) (0x98 + ((x) << 6))	/* Request timeout Registers */
+#define DMA_BUCR(x) (0x98 + ((x) << 6))	/* Bus Utilization Registers */
+#define DMA_CCNR(x) (0x9C + ((x) << 6))	/* Channel counter Registers */
+
+#define DCR_DRST           (1<<1)
+#define DCR_DEN            (1<<0)
+#define DBTOCR_EN          (1<<15)
+#define DBTOCR_CNT(x)      ((x) & 0x7fff)
+#define CNTR_CNT(x)        ((x) & 0xffffff)
+#define CCR_ACRPT          (1<<14)
+#define CCR_DMOD_LINEAR    (0x0 << 12)
+#define CCR_DMOD_2D        (0x1 << 12)
+#define CCR_DMOD_FIFO      (0x2 << 12)
+#define CCR_DMOD_EOBFIFO   (0x3 << 12)
+#define CCR_SMOD_LINEAR    (0x0 << 10)
+#define CCR_SMOD_2D        (0x1 << 10)
+#define CCR_SMOD_FIFO      (0x2 << 10)
+#define CCR_SMOD_EOBFIFO   (0x3 << 10)
+#define CCR_MDIR_DEC       (1<<9)
+#define CCR_MSEL_B         (1<<8)
+#define CCR_DSIZ_32        (0x0 << 6)
+#define CCR_DSIZ_8         (0x1 << 6)
+#define CCR_DSIZ_16        (0x2 << 6)
+#define CCR_SSIZ_32        (0x0 << 4)
+#define CCR_SSIZ_8         (0x1 << 4)
+#define CCR_SSIZ_16        (0x2 << 4)
+#define CCR_REN            (1<<3)
+#define CCR_RPT            (1<<2)
+#define CCR_FRC            (1<<1)
+#define CCR_CEN            (1<<0)
+#define RTOR_EN            (1<<15)
+#define RTOR_CLK           (1<<14)
+#define RTOR_PSC           (1<<13)
+
+/*
+ * struct imx_dma_channel - i.MX specific DMA extension
+ * @name: name specified by DMA client
+ * @irq_handler: client callback for end of transfer
+ * @err_handler: client callback for error condition
+ * @data: clients context data for callbacks
+ * @dma_mode: direction of the transfer %DMA_MODE_READ or %DMA_MODE_WRITE
+ * @sg: pointer to the actual read/written chunk for scatter-gather emulation
+ * @resbytes: total residual number of bytes to transfer
+ *            (it can be lower or same as sum of SG mapped chunk sizes)
+ * @sgcount: number of chunks to be read/written
+ *
+ * Structure is used for IMX DMA processing. It would be probably good
+ * @struct dma_struct in the future for external interfacing and use
+ * @struct imx_dma_channel only as extension to it.
+ */
+
+struct imx_dma_channel {
+	const char *name;
+	void (*irq_handler) (int, void *);
+	void (*err_handler) (int, void *, int errcode);
+	void (*prog_handler) (int, void *, struct scatterlist *);
+	void *data;
+	unsigned int dma_mode;
+	struct scatterlist *sg;
+	unsigned int resbytes;
+	int dma_num;
+
+	int in_use;
+
+	u32 ccr_from_device;
+	u32 ccr_to_device;
+
+	struct timer_list watchdog;
+
+	int hw_chaining;
+};
+
+static void __iomem *imx_dmav1_baseaddr;
+
+static void imx_dmav1_writel(unsigned val, unsigned offset)
+{
+	__raw_writel(val, imx_dmav1_baseaddr + offset);
+}
+
+static unsigned imx_dmav1_readl(unsigned offset)
+{
+	return __raw_readl(imx_dmav1_baseaddr + offset);
+}
+
+static struct imx_dma_channel imx_dma_channels[IMX_DMA_CHANNELS];
+
+static struct clk *dma_clk;
+
+static int imx_dma_hw_chain(struct imx_dma_channel *imxdma)
+{
+	if (cpu_is_mx27())
+		return imxdma->hw_chaining;
+	else
+		return 0;
+}
+
+/*
+ * imx_dma_sg_next - prepare next chunk for scatter-gather DMA emulation
+ */
+static inline int imx_dma_sg_next(int channel, struct scatterlist *sg)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+	unsigned long now;
+
+	if (!imxdma->name) {
+		printk(KERN_CRIT "%s: called for  not allocated channel %d\n",
+		       __func__, channel);
+		return 0;
+	}
+
+	now = min(imxdma->resbytes, sg->length);
+	if (imxdma->resbytes != IMX_DMA_LENGTH_LOOP)
+		imxdma->resbytes -= now;
+
+	if ((imxdma->dma_mode & DMA_MODE_MASK) == DMA_MODE_READ)
+		imx_dmav1_writel(sg->dma_address, DMA_DAR(channel));
+	else
+		imx_dmav1_writel(sg->dma_address, DMA_SAR(channel));
+
+	imx_dmav1_writel(now, DMA_CNTR(channel));
+
+	pr_debug("imxdma%d: next sg chunk dst 0x%08x, src 0x%08x, "
+		"size 0x%08x\n", channel,
+		 imx_dmav1_readl(DMA_DAR(channel)),
+		 imx_dmav1_readl(DMA_SAR(channel)),
+		 imx_dmav1_readl(DMA_CNTR(channel)));
+
+	return now;
+}
+
+/**
+ * imx_dma_setup_single - setup i.MX DMA channel for linear memory to/from
+ * device transfer
+ *
+ * @channel: i.MX DMA channel number
+ * @dma_address: the DMA/physical memory address of the linear data block
+ *		to transfer
+ * @dma_length: length of the data block in bytes
+ * @dev_addr: physical device port address
+ * @dmamode: DMA transfer mode, %DMA_MODE_READ from the device to the memory
+ *           or %DMA_MODE_WRITE from memory to the device
+ *
+ * Return value: if incorrect parameters are provided -%EINVAL.
+ *		Zero indicates success.
+ */
+int
+imx_dma_setup_single(int channel, dma_addr_t dma_address,
+		     unsigned int dma_length, unsigned int dev_addr,
+		     unsigned int dmamode)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+
+	imxdma->sg = NULL;
+	imxdma->dma_mode = dmamode;
+
+	if (!dma_address) {
+		printk(KERN_ERR "imxdma%d: imx_dma_setup_single null address\n",
+		       channel);
+		return -EINVAL;
+	}
+
+	if (!dma_length) {
+		printk(KERN_ERR "imxdma%d: imx_dma_setup_single zero length\n",
+		       channel);
+		return -EINVAL;
+	}
+
+	if ((dmamode & DMA_MODE_MASK) == DMA_MODE_READ) {
+		pr_debug("imxdma%d: %s dma_addressg=0x%08x dma_length=%d "
+			"dev_addr=0x%08x for read\n",
+			channel, __func__, (unsigned int)dma_address,
+			dma_length, dev_addr);
+
+		imx_dmav1_writel(dev_addr, DMA_SAR(channel));
+		imx_dmav1_writel(dma_address, DMA_DAR(channel));
+		imx_dmav1_writel(imxdma->ccr_from_device, DMA_CCR(channel));
+	} else if ((dmamode & DMA_MODE_MASK) == DMA_MODE_WRITE) {
+		pr_debug("imxdma%d: %s dma_addressg=0x%08x dma_length=%d "
+			"dev_addr=0x%08x for write\n",
+			channel, __func__, (unsigned int)dma_address,
+			dma_length, dev_addr);
+
+		imx_dmav1_writel(dma_address, DMA_SAR(channel));
+		imx_dmav1_writel(dev_addr, DMA_DAR(channel));
+		imx_dmav1_writel(imxdma->ccr_to_device,
+				DMA_CCR(channel));
+	} else {
+		printk(KERN_ERR "imxdma%d: imx_dma_setup_single bad dmamode\n",
+		       channel);
+		return -EINVAL;
+	}
+
+	imx_dmav1_writel(dma_length, DMA_CNTR(channel));
+
+	return 0;
+}
+EXPORT_SYMBOL(imx_dma_setup_single);
+
+/**
+ * imx_dma_setup_sg - setup i.MX DMA channel SG list to/from device transfer
+ * @channel: i.MX DMA channel number
+ * @sg: pointer to the scatter-gather list/vector
+ * @sgcount: scatter-gather list hungs count
+ * @dma_length: total length of the transfer request in bytes
+ * @dev_addr: physical device port address
+ * @dmamode: DMA transfer mode, %DMA_MODE_READ from the device to the memory
+ *           or %DMA_MODE_WRITE from memory to the device
+ *
+ * The function sets up DMA channel state and registers to be ready for
+ * transfer specified by provided parameters. The scatter-gather emulation
+ * is set up according to the parameters.
+ *
+ * The full preparation of the transfer requires setup of more register
+ * by the caller before imx_dma_enable() can be called.
+ *
+ * %BLR(channel) holds transfer burst length in bytes, 0 means 64 bytes
+ *
+ * %RSSR(channel) has to be set to the DMA request line source %DMA_REQ_xxx
+ *
+ * %CCR(channel) has to specify transfer parameters, the next settings is
+ * typical for linear or simple scatter-gather transfers if %DMA_MODE_READ is
+ * specified
+ *
+ * %CCR_DMOD_LINEAR | %CCR_DSIZ_32 | %CCR_SMOD_FIFO | %CCR_SSIZ_x
+ *
+ * The typical setup for %DMA_MODE_WRITE is specified by next options
+ * combination
+ *
+ * %CCR_SMOD_LINEAR | %CCR_SSIZ_32 | %CCR_DMOD_FIFO | %CCR_DSIZ_x
+ *
+ * Be careful here and do not mistakenly mix source and target device
+ * port sizes constants, they are really different:
+ * %CCR_SSIZ_8, %CCR_SSIZ_16, %CCR_SSIZ_32,
+ * %CCR_DSIZ_8, %CCR_DSIZ_16, %CCR_DSIZ_32
+ *
+ * Return value: if incorrect parameters are provided -%EINVAL.
+ * Zero indicates success.
+ */
+int
+imx_dma_setup_sg(int channel,
+		 struct scatterlist *sg, unsigned int sgcount,
+		 unsigned int dma_length, unsigned int dev_addr,
+		 unsigned int dmamode)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+
+	if (imxdma->in_use)
+		return -EBUSY;
+
+	imxdma->sg = sg;
+	imxdma->dma_mode = dmamode;
+	imxdma->resbytes = dma_length;
+
+	if (!sg || !sgcount) {
+		printk(KERN_ERR "imxdma%d: imx_dma_setup_sg empty sg list\n",
+		       channel);
+		return -EINVAL;
+	}
+
+	if (!sg->length) {
+		printk(KERN_ERR "imxdma%d: imx_dma_setup_sg zero length\n",
+		       channel);
+		return -EINVAL;
+	}
+
+	if ((dmamode & DMA_MODE_MASK) == DMA_MODE_READ) {
+		pr_debug("imxdma%d: %s sg=%p sgcount=%d total length=%d "
+			"dev_addr=0x%08x for read\n",
+			channel, __func__, sg, sgcount, dma_length, dev_addr);
+
+		imx_dmav1_writel(dev_addr, DMA_SAR(channel));
+		imx_dmav1_writel(imxdma->ccr_from_device, DMA_CCR(channel));
+	} else if ((dmamode & DMA_MODE_MASK) == DMA_MODE_WRITE) {
+		pr_debug("imxdma%d: %s sg=%p sgcount=%d total length=%d "
+			"dev_addr=0x%08x for write\n",
+			channel, __func__, sg, sgcount, dma_length, dev_addr);
+
+		imx_dmav1_writel(dev_addr, DMA_DAR(channel));
+		imx_dmav1_writel(imxdma->ccr_to_device, DMA_CCR(channel));
+	} else {
+		printk(KERN_ERR "imxdma%d: imx_dma_setup_sg bad dmamode\n",
+		       channel);
+		return -EINVAL;
+	}
+
+	imx_dma_sg_next(channel, sg);
+
+	return 0;
+}
+EXPORT_SYMBOL(imx_dma_setup_sg);
+
+int
+imx_dma_config_channel(int channel, unsigned int config_port,
+	unsigned int config_mem, unsigned int dmareq, int hw_chaining)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+	u32 dreq = 0;
+
+	imxdma->hw_chaining = 0;
+
+	if (hw_chaining) {
+		imxdma->hw_chaining = 1;
+		if (!imx_dma_hw_chain(imxdma))
+			return -EINVAL;
+	}
+
+	if (dmareq)
+		dreq = CCR_REN;
+
+	imxdma->ccr_from_device = config_port | (config_mem << 2) | dreq;
+	imxdma->ccr_to_device = config_mem | (config_port << 2) | dreq;
+
+	imx_dmav1_writel(dmareq, DMA_RSSR(channel));
+
+	return 0;
+}
+EXPORT_SYMBOL(imx_dma_config_channel);
+
+void imx_dma_config_burstlen(int channel, unsigned int burstlen)
+{
+	imx_dmav1_writel(burstlen, DMA_BLR(channel));
+}
+EXPORT_SYMBOL(imx_dma_config_burstlen);
+
+/**
+ * imx_dma_setup_handlers - setup i.MX DMA channel end and error notification
+ * handlers
+ * @channel: i.MX DMA channel number
+ * @irq_handler: the pointer to the function called if the transfer
+ *		ends successfully
+ * @err_handler: the pointer to the function called if the premature
+ *		end caused by error occurs
+ * @data: user specified value to be passed to the handlers
+ */
+int
+imx_dma_setup_handlers(int channel,
+		       void (*irq_handler) (int, void *),
+		       void (*err_handler) (int, void *, int),
+		       void *data)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+	unsigned long flags;
+
+	if (!imxdma->name) {
+		printk(KERN_CRIT "%s: called for  not allocated channel %d\n",
+		       __func__, channel);
+		return -ENODEV;
+	}
+
+	local_irq_save(flags);
+	imx_dmav1_writel(1 << channel, DMA_DISR);
+	imxdma->irq_handler = irq_handler;
+	imxdma->err_handler = err_handler;
+	imxdma->data = data;
+	local_irq_restore(flags);
+	return 0;
+}
+EXPORT_SYMBOL(imx_dma_setup_handlers);
+
+/**
+ * imx_dma_setup_progression_handler - setup i.MX DMA channel progression
+ * handlers
+ * @channel: i.MX DMA channel number
+ * @prog_handler: the pointer to the function called if the transfer progresses
+ */
+int
+imx_dma_setup_progression_handler(int channel,
+			void (*prog_handler) (int, void*, struct scatterlist*))
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+	unsigned long flags;
+
+	if (!imxdma->name) {
+		printk(KERN_CRIT "%s: called for  not allocated channel %d\n",
+		       __func__, channel);
+		return -ENODEV;
+	}
+
+	local_irq_save(flags);
+	imxdma->prog_handler = prog_handler;
+	local_irq_restore(flags);
+	return 0;
+}
+EXPORT_SYMBOL(imx_dma_setup_progression_handler);
+
+/**
+ * imx_dma_enable - function to start i.MX DMA channel operation
+ * @channel: i.MX DMA channel number
+ *
+ * The channel has to be allocated by driver through imx_dma_request()
+ * or imx_dma_request_by_prio() function.
+ * The transfer parameters has to be set to the channel registers through
+ * call of the imx_dma_setup_single() or imx_dma_setup_sg() function
+ * and registers %BLR(channel), %RSSR(channel) and %CCR(channel) has to
+ * be set prior this function call by the channel user.
+ */
+void imx_dma_enable(int channel)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+	unsigned long flags;
+
+	pr_debug("imxdma%d: imx_dma_enable\n", channel);
+
+	if (!imxdma->name) {
+		printk(KERN_CRIT "%s: called for  not allocated channel %d\n",
+		       __func__, channel);
+		return;
+	}
+
+	if (imxdma->in_use)
+		return;
+
+	local_irq_save(flags);
+
+	imx_dmav1_writel(1 << channel, DMA_DISR);
+	imx_dmav1_writel(imx_dmav1_readl(DMA_DIMR) & ~(1 << channel), DMA_DIMR);
+	imx_dmav1_writel(imx_dmav1_readl(DMA_CCR(channel)) | CCR_CEN |
+		CCR_ACRPT, DMA_CCR(channel));
+
+#ifdef CONFIG_ARCH_MX2
+	if ((cpu_is_mx21() || cpu_is_mx27()) &&
+			imxdma->sg && imx_dma_hw_chain(imxdma)) {
+		imxdma->sg = sg_next(imxdma->sg);
+		if (imxdma->sg) {
+			u32 tmp;
+			imx_dma_sg_next(channel, imxdma->sg);
+			tmp = imx_dmav1_readl(DMA_CCR(channel));
+			imx_dmav1_writel(tmp | CCR_RPT | CCR_ACRPT,
+				DMA_CCR(channel));
+		}
+	}
+#endif
+	imxdma->in_use = 1;
+
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(imx_dma_enable);
+
+/**
+ * imx_dma_disable - stop, finish i.MX DMA channel operatin
+ * @channel: i.MX DMA channel number
+ */
+void imx_dma_disable(int channel)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+	unsigned long flags;
+
+	pr_debug("imxdma%d: imx_dma_disable\n", channel);
+
+	if (imx_dma_hw_chain(imxdma))
+		del_timer(&imxdma->watchdog);
+
+	local_irq_save(flags);
+	imx_dmav1_writel(imx_dmav1_readl(DMA_DIMR) | (1 << channel), DMA_DIMR);
+	imx_dmav1_writel(imx_dmav1_readl(DMA_CCR(channel)) & ~CCR_CEN,
+			DMA_CCR(channel));
+	imx_dmav1_writel(1 << channel, DMA_DISR);
+	imxdma->in_use = 0;
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(imx_dma_disable);
+
+#ifdef CONFIG_ARCH_MX2
+static void imx_dma_watchdog(unsigned long chno)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[chno];
+
+	imx_dmav1_writel(0, DMA_CCR(chno));
+	imxdma->in_use = 0;
+	imxdma->sg = NULL;
+
+	if (imxdma->err_handler)
+		imxdma->err_handler(chno, imxdma->data, IMX_DMA_ERR_TIMEOUT);
+}
+#endif
+
+static irqreturn_t dma_err_handler(int irq, void *dev_id)
+{
+	int i, disr;
+	struct imx_dma_channel *imxdma;
+	unsigned int err_mask;
+	int errcode;
+
+	disr = imx_dmav1_readl(DMA_DISR);
+
+	err_mask = imx_dmav1_readl(DMA_DBTOSR) |
+		   imx_dmav1_readl(DMA_DRTOSR) |
+		   imx_dmav1_readl(DMA_DSESR)  |
+		   imx_dmav1_readl(DMA_DBOSR);
+
+	if (!err_mask)
+		return IRQ_HANDLED;
+
+	imx_dmav1_writel(disr & err_mask, DMA_DISR);
+
+	for (i = 0; i < IMX_DMA_CHANNELS; i++) {
+		if (!(err_mask & (1 << i)))
+			continue;
+		imxdma = &imx_dma_channels[i];
+		errcode = 0;
+
+		if (imx_dmav1_readl(DMA_DBTOSR) & (1 << i)) {
+			imx_dmav1_writel(1 << i, DMA_DBTOSR);
+			errcode |= IMX_DMA_ERR_BURST;
+		}
+		if (imx_dmav1_readl(DMA_DRTOSR) & (1 << i)) {
+			imx_dmav1_writel(1 << i, DMA_DRTOSR);
+			errcode |= IMX_DMA_ERR_REQUEST;
+		}
+		if (imx_dmav1_readl(DMA_DSESR) & (1 << i)) {
+			imx_dmav1_writel(1 << i, DMA_DSESR);
+			errcode |= IMX_DMA_ERR_TRANSFER;
+		}
+		if (imx_dmav1_readl(DMA_DBOSR) & (1 << i)) {
+			imx_dmav1_writel(1 << i, DMA_DBOSR);
+			errcode |= IMX_DMA_ERR_BUFFER;
+		}
+		if (imxdma->name && imxdma->err_handler) {
+			imxdma->err_handler(i, imxdma->data, errcode);
+			continue;
+		}
+
+		imx_dma_channels[i].sg = NULL;
+
+		printk(KERN_WARNING
+		       "DMA timeout on channel %d (%s) -%s%s%s%s\n",
+		       i, imxdma->name,
+		       errcode & IMX_DMA_ERR_BURST ?    " burst" : "",
+		       errcode & IMX_DMA_ERR_REQUEST ?  " request" : "",
+		       errcode & IMX_DMA_ERR_TRANSFER ? " transfer" : "",
+		       errcode & IMX_DMA_ERR_BUFFER ?   " buffer" : "");
+	}
+	return IRQ_HANDLED;
+}
+
+static void dma_irq_handle_channel(int chno)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[chno];
+
+	if (!imxdma->name) {
+		/*
+		 * IRQ for an unregistered DMA channel:
+		 * let's clear the interrupts and disable it.
+		 */
+		printk(KERN_WARNING
+		       "spurious IRQ for DMA channel %d\n", chno);
+		return;
+	}
+
+	if (imxdma->sg) {
+		u32 tmp;
+		struct scatterlist *current_sg = imxdma->sg;
+		imxdma->sg = sg_next(imxdma->sg);
+
+		if (imxdma->sg) {
+			imx_dma_sg_next(chno, imxdma->sg);
+
+			tmp = imx_dmav1_readl(DMA_CCR(chno));
+
+			if (imx_dma_hw_chain(imxdma)) {
+				/* FIXME: The timeout should probably be
+				 * configurable
+				 */
+				mod_timer(&imxdma->watchdog,
+					jiffies + msecs_to_jiffies(500));
+
+				tmp |= CCR_CEN | CCR_RPT | CCR_ACRPT;
+				imx_dmav1_writel(tmp, DMA_CCR(chno));
+			} else {
+				imx_dmav1_writel(tmp & ~CCR_CEN, DMA_CCR(chno));
+				tmp |= CCR_CEN;
+			}
+
+			imx_dmav1_writel(tmp, DMA_CCR(chno));
+
+			if (imxdma->prog_handler)
+				imxdma->prog_handler(chno, imxdma->data,
+						current_sg);
+
+			return;
+		}
+
+		if (imx_dma_hw_chain(imxdma)) {
+			del_timer(&imxdma->watchdog);
+			return;
+		}
+	}
+
+	imx_dmav1_writel(0, DMA_CCR(chno));
+	imxdma->in_use = 0;
+	if (imxdma->irq_handler)
+		imxdma->irq_handler(chno, imxdma->data);
+}
+
+static irqreturn_t dma_irq_handler(int irq, void *dev_id)
+{
+	int i, disr;
+
+#ifdef CONFIG_ARCH_MX2
+	if (cpu_is_mx21() || cpu_is_mx27())
+		dma_err_handler(irq, dev_id);
+#endif
+
+	disr = imx_dmav1_readl(DMA_DISR);
+
+	pr_debug("imxdma: dma_irq_handler called, disr=0x%08x\n",
+		     disr);
+
+	imx_dmav1_writel(disr, DMA_DISR);
+	for (i = 0; i < IMX_DMA_CHANNELS; i++) {
+		if (disr & (1 << i))
+			dma_irq_handle_channel(i);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * imx_dma_request - request/allocate specified channel number
+ * @channel: i.MX DMA channel number
+ * @name: the driver/caller own non-%NULL identification
+ */
+int imx_dma_request(int channel, const char *name)
+{
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+	unsigned long flags;
+	int ret = 0;
+
+	/* basic sanity checks */
+	if (!name)
+		return -EINVAL;
+
+	if (channel >= IMX_DMA_CHANNELS) {
+		printk(KERN_CRIT "%s: called for  non-existed channel %d\n",
+		       __func__, channel);
+		return -EINVAL;
+	}
+
+	local_irq_save(flags);
+	if (imxdma->name) {
+		local_irq_restore(flags);
+		return -EBUSY;
+	}
+	memset(imxdma, 0, sizeof(imxdma));
+	imxdma->name = name;
+	local_irq_restore(flags); /* request_irq() can block */
+
+#ifdef CONFIG_ARCH_MX2
+	if (cpu_is_mx21() || cpu_is_mx27()) {
+		ret = request_irq(MX2x_INT_DMACH0 + channel,
+				dma_irq_handler, 0, "DMA", NULL);
+		if (ret) {
+			imxdma->name = NULL;
+			pr_crit("Can't register IRQ %d for DMA channel %d\n",
+					MX2x_INT_DMACH0 + channel, channel);
+			return ret;
+		}
+		init_timer(&imxdma->watchdog);
+		imxdma->watchdog.function = &imx_dma_watchdog;
+		imxdma->watchdog.data = channel;
+	}
+#endif
+
+	return ret;
+}
+EXPORT_SYMBOL(imx_dma_request);
+
+/**
+ * imx_dma_free - release previously acquired channel
+ * @channel: i.MX DMA channel number
+ */
+void imx_dma_free(int channel)
+{
+	unsigned long flags;
+	struct imx_dma_channel *imxdma = &imx_dma_channels[channel];
+
+	if (!imxdma->name) {
+		printk(KERN_CRIT
+		       "%s: trying to free free channel %d\n",
+		       __func__, channel);
+		return;
+	}
+
+	local_irq_save(flags);
+	/* Disable interrupts */
+	imx_dma_disable(channel);
+	imxdma->name = NULL;
+
+#ifdef CONFIG_ARCH_MX2
+	if (cpu_is_mx21() || cpu_is_mx27())
+		free_irq(MX2x_INT_DMACH0 + channel, NULL);
+#endif
+
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL(imx_dma_free);
+
+/**
+ * imx_dma_request_by_prio - find and request some of free channels best
+ * suiting requested priority
+ * @channel: i.MX DMA channel number
+ * @name: the driver/caller own non-%NULL identification
+ *
+ * This function tries to find a free channel in the specified priority group
+ * if the priority cannot be achieved it tries to look for free channel
+ * in the higher and then even lower priority groups.
+ *
+ * Return value: If there is no free channel to allocate, -%ENODEV is returned.
+ *               On successful allocation channel is returned.
+ */
+int imx_dma_request_by_prio(const char *name, enum imx_dma_prio prio)
+{
+	int i;
+	int best;
+
+	switch (prio) {
+	case (DMA_PRIO_HIGH):
+		best = 8;
+		break;
+	case (DMA_PRIO_MEDIUM):
+		best = 4;
+		break;
+	case (DMA_PRIO_LOW):
+	default:
+		best = 0;
+		break;
+	}
+
+	for (i = best; i < IMX_DMA_CHANNELS; i++)
+		if (!imx_dma_request(i, name))
+			return i;
+
+	for (i = best - 1; i >= 0; i--)
+		if (!imx_dma_request(i, name))
+			return i;
+
+	printk(KERN_ERR "%s: no free DMA channel found\n", __func__);
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL(imx_dma_request_by_prio);
+
+static int __init imx_dma_init(void)
+{
+	int ret = 0;
+	int i;
+
+#ifdef CONFIG_ARCH_MX1
+	if (cpu_is_mx1())
+		imx_dmav1_baseaddr = MX1_IO_ADDRESS(MX1_DMA_BASE_ADDR);
+	else
+#endif
+#ifdef CONFIG_MACH_MX21
+	if (cpu_is_mx21())
+		imx_dmav1_baseaddr = MX21_IO_ADDRESS(MX21_DMA_BASE_ADDR);
+	else
+#endif
+#ifdef CONFIG_MACH_MX27
+	if (cpu_is_mx27())
+		imx_dmav1_baseaddr = MX27_IO_ADDRESS(MX27_DMA_BASE_ADDR);
+	else
+#endif
+		BUG();
+
+	dma_clk = clk_get(NULL, "dma");
+	clk_enable(dma_clk);
+
+	/* reset DMA module */
+	imx_dmav1_writel(DCR_DRST, DMA_DCR);
+
+#ifdef CONFIG_ARCH_MX1
+	if (cpu_is_mx1()) {
+		ret = request_irq(MX1_DMA_INT, dma_irq_handler, 0, "DMA", NULL);
+		if (ret) {
+			pr_crit("Wow!  Can't register IRQ for DMA\n");
+			return ret;
+		}
+
+		ret = request_irq(MX1_DMA_ERR, dma_err_handler, 0, "DMA", NULL);
+		if (ret) {
+			pr_crit("Wow!  Can't register ERRIRQ for DMA\n");
+			free_irq(MX1_DMA_INT, NULL);
+			return ret;
+		}
+	}
+#endif
+	/* enable DMA module */
+	imx_dmav1_writel(DCR_DEN, DMA_DCR);
+
+	/* clear all interrupts */
+	imx_dmav1_writel((1 << IMX_DMA_CHANNELS) - 1, DMA_DISR);
+
+	/* disable interrupts */
+	imx_dmav1_writel((1 << IMX_DMA_CHANNELS) - 1, DMA_DIMR);
+
+	for (i = 0; i < IMX_DMA_CHANNELS; i++) {
+		imx_dma_channels[i].sg = NULL;
+		imx_dma_channels[i].dma_num = i;
+	}
+
+	return ret;
+}
+
+arch_initcall(imx_dma_init);