[ARM] S3C64XX: DMA support

Add support for the DMA blocks in the S3C64XX series of CPUS,
which are based on the ARM PL080 PrimeCell system.

Unfortunately, these DMA controllers diverge from the PL080
design by adding another DMA controller register and
configuration for OneNAND.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

arch/arm/include/asm/hardware/pl080.h

+/* arch/arm/include/asm/hardware/pl080.h
+ *
+ * Copyright 2008 Openmoko, Inc.
+ * Copyright 2008 Simtec Electronics
+ *      http://armlinux.simtec.co.uk/
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ * ARM PrimeCell PL080 DMA controller
+ *
+ * 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.
+*/
+
+/* Note, there are some Samsung updates to this controller block which
+ * make it not entierly compatible with the PL080 specification from
+ * ARM. When in doubt, check the Samsung documentation first.
+ *
+ * The Samsung defines are PL080S, and add an extra controll register,
+ * the ability to move more than 2^11 counts of data and some extra
+ * OneNAND features.
+*/
+
+#define PL080_INT_STATUS			(0x00)
+#define PL080_TC_STATUS				(0x04)
+#define PL080_TC_CLEAR				(0x08)
+#define PL080_ERR_STATUS			(0x0C)
+#define PL080_ERR_CLEAR				(0x10)
+#define PL080_RAW_TC_STATUS			(0x14)
+#define PL080_RAW_ERR_STATUS			(0x18)
+#define PL080_EN_CHAN				(0x1c)
+#define PL080_SOFT_BREQ				(0x20)
+#define PL080_SOFT_SREQ				(0x24)
+#define PL080_SOFT_LBREQ			(0x28)
+#define PL080_SOFT_LSREQ			(0x2C)
+
+#define PL080_CONFIG				(0x30)
+#define PL080_CONFIG_M2_BE			(1 << 2)
+#define PL080_CONFIG_M1_BE			(1 << 1)
+#define PL080_CONFIG_ENABLE			(1 << 0)
+
+#define PL080_SYNC				(0x34)
+
+/* Per channel configuration registers */
+
+#define PL008_Cx_STRIDE				(0x20)
+#define PL080_Cx_BASE(x)			((0x100 + (x * 0x20)))
+#define PL080_Cx_SRC_ADDR(x)			((0x100 + (x * 0x20)))
+#define PL080_Cx_DST_ADDR(x)			((0x104 + (x * 0x20)))
+#define PL080_Cx_LLI(x)				((0x108 + (x * 0x20)))
+#define PL080_Cx_CONTROL(x)			((0x10C + (x * 0x20)))
+#define PL080_Cx_CONFIG(x)			((0x110 + (x * 0x20)))
+#define PL080S_Cx_CONTROL2(x)			((0x110 + (x * 0x20)))
+#define PL080S_Cx_CONFIG(x)			((0x114 + (x * 0x20)))
+
+#define PL080_CH_SRC_ADDR			(0x00)
+#define PL080_CH_DST_ADDR			(0x04)
+#define PL080_CH_LLI				(0x08)
+#define PL080_CH_CONTROL			(0x0C)
+#define PL080_CH_CONFIG				(0x10)
+#define PL080S_CH_CONTROL2			(0x10)
+#define PL080S_CH_CONFIG			(0x14)
+
+#define PL080_LLI_ADDR_MASK			(0x3fffffff << 2)
+#define PL080_LLI_ADDR_SHIFT			(2)
+#define PL080_LLI_LM_AHB2			(1 << 0)
+
+#define PL080_CONTROL_TC_IRQ_EN			(1 << 31)
+#define PL080_CONTROL_PROT_MASK			(0x7 << 28)
+#define PL080_CONTROL_PROT_SHIFT		(28)
+#define PL080_CONTROL_PROT_SYS			(1 << 28)
+#define PL080_CONTROL_DST_INCR			(1 << 27)
+#define PL080_CONTROL_SRC_INCR			(1 << 26)
+#define PL080_CONTROL_DST_AHB2			(1 << 25)
+#define PL080_CONTROL_SRC_AHB2			(1 << 24)
+#define PL080_CONTROL_DWIDTH_MASK		(0x7 << 21)
+#define PL080_CONTROL_DWIDTH_SHIFT		(21)
+#define PL080_CONTROL_SWIDTH_MASK		(0x7 << 18)
+#define PL080_CONTROL_SWIDTH_SHIFT		(18)
+#define PL080_CONTROL_DB_SIZE_MASK		(0x7 << 15)
+#define PL080_CONTROL_DB_SIZE_SHIFT		(15)
+#define PL080_CONTROL_SB_SIZE_MASK		(0x7 << 12)
+#define PL080_CONTROL_SB_SIZE_SHIFT		(12)
+#define PL080_CONTROL_TRANSFER_SIZE_MASK	(0xfff << 0)
+#define PL080_CONTROL_TRANSFER_SIZE_SHIFT	(0)
+
+#define PL080_BSIZE_1				(0x0)
+#define PL080_BSIZE_4				(0x1)
+#define PL080_BSIZE_8				(0x2)
+#define PL080_BSIZE_16				(0x3)
+#define PL080_BSIZE_32				(0x4)
+#define PL080_BSIZE_64				(0x5)
+#define PL080_BSIZE_128				(0x6)
+#define PL080_BSIZE_256				(0x7)
+
+#define PL080_WIDTH_8BIT			(0x0)
+#define PL080_WIDTH_16BIT			(0x1)
+#define PL080_WIDTH_32BIT			(0x2)
+
+#define PL080_CONFIG_HALT			(1 << 18)
+#define PL080_CONFIG_ACTIVE			(1 << 17)  /* RO */
+#define PL080_CONFIG_LOCK			(1 << 16)
+#define PL080_CONFIG_TC_IRQ_MASK		(1 << 15)
+#define PL080_CONFIG_ERR_IRQ_MASK		(1 << 14)
+#define PL080_CONFIG_FLOW_CONTROL_MASK		(0x7 << 11)
+#define PL080_CONFIG_FLOW_CONTROL_SHIFT		(11)
+#define PL080_CONFIG_DST_SEL_MASK		(0xf << 6)
+#define PL080_CONFIG_DST_SEL_SHIFT		(6)
+#define PL080_CONFIG_SRC_SEL_MASK		(0xf << 1)
+#define PL080_CONFIG_SRC_SEL_SHIFT		(1)
+#define PL080_CONFIG_ENABLE			(1 << 0)
+
+#define PL080_FLOW_MEM2MEM			(0x0)
+#define PL080_FLOW_MEM2PER			(0x1)
+#define PL080_FLOW_PER2MEM			(0x2)
+#define PL080_FLOW_SRC2DST			(0x3)
+#define PL080_FLOW_SRC2DST_DST			(0x4)
+#define PL080_FLOW_MEM2PER_PER			(0x5)
+#define PL080_FLOW_PER2MEM_PER			(0x6)
+#define PL080_FLOW_SRC2DST_SRC			(0x7)
+
+/* DMA linked list chain structure */
+
+struct pl080_lli {
+	u32	src_addr;
+	u32	dst_addr;
+	u32	next_lli;
+	u32	control0;
+};
+
+struct pl080s_lli {
+	u32	src_addr;
+	u32	dst_addr;
+	u32	next_lli;
+	u32	control0;
+	u32	control1;
+};
+

arch/arm/mach-s3c6400/include/mach/dma.h

@@ -11,6 +11,63 @@
 #ifndef __ASM_ARCH_DMA_H
 #define __ASM_ARCH_DMA_H __FILE__
 
-/* currently nothing here, placeholder */
+#define S3C_DMA_CHANNELS	(16)
+
+/* see mach-s3c2410/dma.h for notes on dma channel numbers */
+
+/* Note, for the S3C64XX architecture we keep the DMACH_
+ * defines in the order they are allocated to [S]DMA0/[S]DMA1
+ * so that is easy to do DHACH_ -> DMA controller conversion
+ */
+enum dma_ch {
+	/* DMA0/SDMA0 */
+	DMACH_UART0 = 0,
+	DMACH_UART0_SRC2,
+	DMACH_UART1,
+	DMACH_UART1_SRC2,
+	DMACH_UART2,
+	DMACH_UART2_SRC2,
+	DMACH_UART3,
+	DMACH_UART3_SRC2,
+	DMACH_PCM0_TX,
+	DMACH_PCM0_RX,
+	DMACH_I2S0_OUT,
+	DMACH_I2S0_IN,
+	DMACH_SPI0_TX,
+	DMACH_SPI0_RX,
+	DMACH_HSI_I2SV40_TX,
+	DMACH_HSI_I2SV40_RX,
+
+	/* DMA1/SDMA1 */
+	DMACH_PCM1_TX = 16,
+	DMACH_PCM1_RX,
+	DMACH_I2S1_OUT,
+	DMACH_I2S1_IN,
+	DMACH_SPI1_TX,
+	DMACH_SPI1_RX,
+	DMACH_AC97_PCMOUT,
+	DMACH_AC97_PCMIN,
+	DMACH_AC97_MICIN,
+	DMACH_PWM,
+	DMACH_IRDA,
+	DMACH_EXTERNAL,
+	DMACH_RES1,
+	DMACH_RES2,
+	DMACH_SECURITY_RX,	/* SDMA1 only */
+	DMACH_SECURITY_TX,	/* SDMA1 only */
+	DMACH_MAX		/* the end */
+};
+
+static __inline__ int s3c_dma_has_circular(void)
+{
+	/* we will be supporting ciruclar buffers as soon as we have DMA
+	 * engine support.
+	 */
+	return 1;
+}
+
+#define S3C2410_DMAF_CIRCULAR		(1 << 0)
+
+#include <plat/dma.h>
 
 #endif /* __ASM_ARCH_IRQ_H */

arch/arm/plat-s3c64xx/Kconfig

@@ -38,6 +38,10 @@ config CPU_S3C6400_CLOCK
 	  Common clock support code for the S3C6400 that is shared
 	  by other CPUs in the series, such as the S3C6410.
 
+config S3C64XX_DMA
+	bool "S3C64XX DMA"
+	select S3C_DMA
+
 # platform specific device setup
 
 config S3C64XX_SETUP_I2C0

arch/arm/plat-s3c64xx/Makefile

@@ -24,6 +24,10 @@ obj-y				+= gpiolib.o
 obj-$(CONFIG_CPU_S3C6400_INIT)	+= s3c6400-init.o
 obj-$(CONFIG_CPU_S3C6400_CLOCK)	+= s3c6400-clock.o
 
+# DMA support
+
+obj-$(CONFIG_S3C64XX_DMA)	+= dma.o
+
 # Device setup
 
 obj-$(CONFIG_S3C64XX_SETUP_I2C0) += setup-i2c0.o

arch/arm/plat-s3c64xx/dma.c

+/* linux/arch/arm/plat-s3c64xx/dma.c
+ *
+ * Copyright 2009 Openmoko, Inc.
+ * Copyright 2009 Simtec Electronics
+ *	Ben Dooks <ben@simtec.co.uk>
+ *	http://armlinux.simtec.co.uk/
+ *
+ * S3C64XX DMA core
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/dmapool.h>
+#include <linux/sysdev.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+
+#include <mach/dma.h>
+#include <mach/map.h>
+#include <mach/irqs.h>
+
+#include <plat/dma-plat.h>
+#include <plat/regs-sys.h>
+
+#include <asm/hardware/pl080.h>
+
+/* dma channel state information */
+
+struct s3c64xx_dmac {
+	struct sys_device	 sysdev;
+	struct clk		*clk;
+	void __iomem		*regs;
+	struct s3c2410_dma_chan *channels;
+	enum dma_ch		 chanbase;
+};
+
+/* pool to provide LLI buffers */
+static struct dma_pool *dma_pool;
+
+/* Debug configuration and code */
+
+static unsigned char debug_show_buffs = 0;
+
+static void dbg_showchan(struct s3c2410_dma_chan *chan)
+{
+	pr_debug("DMA%d: %08x->%08x L %08x C %08x,%08x S %08x\n",
+		 chan->number,
+		 readl(chan->regs + PL080_CH_SRC_ADDR),
+		 readl(chan->regs + PL080_CH_DST_ADDR),
+		 readl(chan->regs + PL080_CH_LLI),
+		 readl(chan->regs + PL080_CH_CONTROL),
+		 readl(chan->regs + PL080S_CH_CONTROL2),
+		 readl(chan->regs + PL080S_CH_CONFIG));
+}
+
+static void show_lli(struct pl080s_lli *lli)
+{
+	pr_debug("LLI[%p] %08x->%08x, NL %08x C %08x,%08x\n",
+		 lli, lli->src_addr, lli->dst_addr, lli->next_lli,
+		 lli->control0, lli->control1);
+}
+
+static void dbg_showbuffs(struct s3c2410_dma_chan *chan)
+{
+	struct s3c64xx_dma_buff *ptr;
+	struct s3c64xx_dma_buff *end;
+
+	pr_debug("DMA%d: buffs next %p, curr %p, end %p\n",
+		 chan->number, chan->next, chan->curr, chan->end);
+
+	ptr = chan->next;
+	end = chan->end;
+
+	if (debug_show_buffs) {
+		for (; ptr != NULL; ptr = ptr->next) {
+			pr_debug("DMA%d: %08x ",
+				 chan->number, ptr->lli_dma);
+			show_lli(ptr->lli);
+		}
+	}
+}
+
+/* End of Debug */
+
+static struct s3c2410_dma_chan *s3c64xx_dma_map_channel(unsigned int channel)
+{
+	struct s3c2410_dma_chan *chan;
+	unsigned int start, offs;
+
+	start = 0;
+
+	if (channel >= DMACH_PCM1_TX)
+		start = 8;
+
+	for (offs = 0; offs < 8; offs++) {
+		chan = &s3c2410_chans[start + offs];
+		if (!chan->in_use)
+			goto found;
+	}
+
+	return NULL;
+
+found:
+	s3c_dma_chan_map[channel] = chan;
+	return chan;
+}
+
+int s3c2410_dma_config(unsigned int channel, int xferunit)
+{
+	struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+
+	if (chan == NULL)
+		return -EINVAL;
+
+	switch (xferunit) {
+	case 1:
+		chan->hw_width = 0;
+		break;
+	case 2:
+		chan->hw_width = 1;
+		break;
+	case 4:
+		chan->hw_width = 2;
+		break;
+	default:
+		printk(KERN_ERR "%s: illegal width %d\n", __func__, xferunit);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(s3c2410_dma_config);
+
+static void s3c64xx_dma_fill_lli(struct s3c2410_dma_chan *chan,
+				 struct pl080s_lli *lli,
+				 dma_addr_t data, int size)
+{
+	dma_addr_t src, dst;
+	u32 control0, control1;
+
+	switch (chan->source) {
+	case S3C2410_DMASRC_HW:
+		src = chan->dev_addr;
+		dst = data;
+		control0 = PL080_CONTROL_SRC_AHB2;
+		control0 |= (u32)chan->hw_width << PL080_CONTROL_SWIDTH_SHIFT;
+		control0 |= 2 << PL080_CONTROL_DWIDTH_SHIFT;
+		control0 |= PL080_CONTROL_DST_INCR;
+		break;
+
+	case S3C2410_DMASRC_MEM:
+		src = data;
+		dst = chan->dev_addr;
+		control0 = PL080_CONTROL_DST_AHB2;
+		control0 |= (u32)chan->hw_width << PL080_CONTROL_DWIDTH_SHIFT;
+		control0 |= 2 << PL080_CONTROL_SWIDTH_SHIFT;
+		control0 |= PL080_CONTROL_SRC_INCR;
+		break;
+	default:
+		BUG();
+	}
+
+	/* note, we do not currently setup any of the burst controls */
+
+	control1 = size >> chan->hw_width;	/* size in no of xfers */
+	control0 |= PL080_CONTROL_PROT_SYS;	/* always in priv. mode */
+	control0 |= PL080_CONTROL_TC_IRQ_EN;	/* always fire IRQ */
+
+	lli->src_addr = src;
+	lli->dst_addr = dst;
+	lli->next_lli = 0;
+	lli->control0 = control0;
+	lli->control1 = control1;
+}
+
+static void s3c64xx_lli_to_regs(struct s3c2410_dma_chan *chan,
+				struct pl080s_lli *lli)
+{
+	void __iomem *regs = chan->regs;
+
+	pr_debug("%s: LLI %p => regs\n", __func__, lli);
+	show_lli(lli);
+
+	writel(lli->src_addr, regs + PL080_CH_SRC_ADDR);
+	writel(lli->dst_addr, regs + PL080_CH_DST_ADDR);
+	writel(lli->next_lli, regs + PL080_CH_LLI);
+	writel(lli->control0, regs + PL080_CH_CONTROL);
+	writel(lli->control1, regs + PL080S_CH_CONTROL2);
+}
+
+static int s3c64xx_dma_start(struct s3c2410_dma_chan *chan)
+{
+	struct s3c64xx_dmac *dmac = chan->dmac;
+	u32 config;
+	u32 bit = chan->bit;
+
+	dbg_showchan(chan);
+
+	pr_debug("%s: clearing interrupts\n", __func__);
+
+	/* clear interrupts */
+	writel(bit, dmac->regs + PL080_TC_CLEAR);
+	writel(bit, dmac->regs + PL080_ERR_CLEAR);
+
+	pr_debug("%s: starting channel\n", __func__);
+
+	config = readl(chan->regs + PL080S_CH_CONFIG);
+	config |= PL080_CONFIG_ENABLE;
+
+	pr_debug("%s: writing config %08x\n", __func__, config);
+	writel(config, chan->regs + PL080S_CH_CONFIG);
+
+	return 0;
+}
+
+static int s3c64xx_dma_stop(struct s3c2410_dma_chan *chan)
+{
+	u32 config;
+	int timeout;
+
+	pr_debug("%s: stopping channel\n", __func__);
+
+	dbg_showchan(chan);
+
+	config = readl(chan->regs + PL080S_CH_CONFIG);
+	config |= PL080_CONFIG_HALT;
+	writel(config, chan->regs + PL080S_CH_CONFIG);
+
+	timeout = 1000;
+	do {
+		config = readl(chan->regs + PL080S_CH_CONFIG);
+		pr_debug("%s: %d - config %08x\n", __func__, timeout, config);
+		if (config & PL080_CONFIG_ACTIVE)
+			udelay(10);
+		else
+			break;
+		} while (--timeout > 0);
+
+	if (config & PL080_CONFIG_ACTIVE) {
+		printk(KERN_ERR "%s: channel still active\n", __func__);
+		return -EFAULT;
+	}
+
+	config = readl(chan->regs + PL080S_CH_CONFIG);
+	config &= ~PL080_CONFIG_ENABLE;
+	writel(config, chan->regs + PL080S_CH_CONFIG);
+
+	return 0;
+}
+
+static inline void s3c64xx_dma_bufffdone(struct s3c2410_dma_chan *chan,
+					 struct s3c64xx_dma_buff *buf,
+					 enum s3c2410_dma_buffresult result)
+{
+	if (chan->callback_fn != NULL)
+		(chan->callback_fn)(chan, buf->pw, 0, result);
+}
+
+static void s3c64xx_dma_freebuff(struct s3c64xx_dma_buff *buff)
+{
+	dma_pool_free(dma_pool, buff->lli, buff->lli_dma);
+	kfree(buff);
+}
+
+static int s3c64xx_dma_flush(struct s3c2410_dma_chan *chan)
+{
+	struct s3c64xx_dma_buff *buff, *next;
+	u32 config;
+
+	dbg_showchan(chan);
+
+	pr_debug("%s: flushing channel\n", __func__);
+
+	config = readl(chan->regs + PL080S_CH_CONFIG);
+	config &= ~PL080_CONFIG_ENABLE;
+	writel(config, chan->regs + PL080S_CH_CONFIG);
+
+	/* dump all the buffers associated with this channel */
+
+	for (buff = chan->curr; buff != NULL; buff = next) {
+		next = buff->next;
+		pr_debug("%s: buff %p (next %p)\n", __func__, buff, buff->next);
+
+		s3c64xx_dma_bufffdone(chan, buff, S3C2410_RES_ABORT);
+		s3c64xx_dma_freebuff(buff);
+	}
+
+	chan->curr = chan->next = chan->end = NULL;
+
+	return 0;
+}
+
+int s3c2410_dma_ctrl(unsigned int channel, enum s3c2410_chan_op op)
+{
+	struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+
+	WARN_ON(!chan);
+	if (!chan)
+		return -EINVAL;
+
+	switch (op) {
+	case S3C2410_DMAOP_START:
+		return s3c64xx_dma_start(chan);
+
+	case S3C2410_DMAOP_STOP:
+		return s3c64xx_dma_stop(chan);
+
+	case S3C2410_DMAOP_FLUSH:
+		return s3c64xx_dma_flush(chan);
+
+	/* belive PAUSE/RESUME are no-ops */
+	case S3C2410_DMAOP_PAUSE:
+	case S3C2410_DMAOP_RESUME:
+	case S3C2410_DMAOP_STARTED:
+	case S3C2410_DMAOP_TIMEOUT:
+		return 0;
+	}
+
+	return -ENOENT;
+}
+EXPORT_SYMBOL(s3c2410_dma_ctrl);
+
+/* s3c2410_dma_enque
+ *
+ */
+
+int s3c2410_dma_enqueue(unsigned int channel, void *id,
+			dma_addr_t data, int size)
+{
+	struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+	struct s3c64xx_dma_buff *next;
+	struct s3c64xx_dma_buff *buff;
+	struct pl080s_lli *lli;
+	int ret;
+
+	WARN_ON(!chan);
+	if (!chan)
+		return -EINVAL;
+
+	buff = kzalloc(sizeof(struct s3c64xx_dma_buff), GFP_KERNEL);
+	if (!buff) {
+		printk(KERN_ERR "%s: no memory for buffer\n", __func__);
+		return -ENOMEM;
+	}
+
+	lli = dma_pool_alloc(dma_pool, GFP_KERNEL, &buff->lli_dma);
+	if (!lli) {
+		printk(KERN_ERR "%s: no memory for lli\n", __func__);
+		ret = -ENOMEM;
+		goto err_buff;
+	}
+
+	pr_debug("%s: buff %p, dp %08x lli (%p, %08x) %d\n",
+		 __func__, buff, data, lli, (u32)buff->lli_dma, size);
+
+	buff->lli = lli;
+	buff->pw = id;
+
+	s3c64xx_dma_fill_lli(chan, lli, data, size);
+
+	if ((next = chan->next) != NULL) {
+		struct s3c64xx_dma_buff *end = chan->end;
+		struct pl080s_lli *endlli = end->lli;
+
+		pr_debug("enquing onto channel\n");
+
+		end->next = buff;
+		endlli->next_lli = buff->lli_dma;
+
+		if (chan->flags & S3C2410_DMAF_CIRCULAR) {
+			struct s3c64xx_dma_buff *curr = chan->curr;
+			lli->next_lli = curr->lli_dma;
+		}
+
+		if (next == chan->curr) {
+			writel(buff->lli_dma, chan->regs + PL080_CH_LLI);
+			chan->next = buff;
+		}
+
+		show_lli(endlli);
+		chan->end = buff;
+	} else {
+		pr_debug("enquing onto empty channel\n");
+
+		chan->curr = buff;
+		chan->next = buff;
+		chan->end = buff;
+
+		s3c64xx_lli_to_regs(chan, lli);
+	}
+
+	show_lli(lli);
+
+	dbg_showchan(chan);
+	dbg_showbuffs(chan);
+	return 0;
+
+err_buff:
+	kfree(buff);
+	return ret;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_enqueue);
+
+
+int s3c2410_dma_devconfig(int channel,
+			  enum s3c2410_dmasrc source,
+			  unsigned long devaddr)
+{
+	struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+	u32 peripheral;
+	u32 config = 0;
+
+	printk("%s: channel %d, source %d, dev %08lx, chan %p\n",
+		 __func__, channel, source, devaddr, chan);
+
+	WARN_ON(!chan);
+	if (!chan)
+		return -EINVAL;
+
+	peripheral = (chan->peripheral & 0xf);
+	chan->source = source;
+	chan->dev_addr = devaddr;
+
+	pr_debug("%s: peripheral %d\n", __func__, peripheral);
+
+	switch (source) {
+	case S3C2410_DMASRC_HW:
+		config = 2 << PL080_CONFIG_FLOW_CONTROL_SHIFT;
+		config |= peripheral << PL080_CONFIG_SRC_SEL_SHIFT;
+		break;
+	case S3C2410_DMASRC_MEM:
+		config = 1 << PL080_CONFIG_FLOW_CONTROL_SHIFT;
+		config |= peripheral << PL080_CONFIG_DST_SEL_SHIFT;
+		break;
+	default:
+		printk(KERN_ERR "%s: bad source\n", __func__);
+		return -EINVAL;
+	}
+
+	/* allow TC and ERR interrupts */
+	config |= PL080_CONFIG_TC_IRQ_MASK;
+	config |= PL080_CONFIG_ERR_IRQ_MASK;
+
+	pr_debug("%s: config %08x\n", __func__, config);
+
+	writel(config, chan->regs + PL080S_CH_CONFIG);
+
+	return 0;
+}
+EXPORT_SYMBOL(s3c2410_dma_devconfig);
+
+
+int s3c2410_dma_getposition(unsigned int channel,
+			    dma_addr_t *src, dma_addr_t *dst)
+{
+	struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+
+	WARN_ON(!chan);
+	if (!chan)
+		return -EINVAL;
+
+	if (src != NULL)
+		*src = readl(chan->regs + PL080_CH_SRC_ADDR);
+
+	if (dst != NULL)
+		*dst = readl(chan->regs + PL080_CH_DST_ADDR);
+
+	return 0;
+}
+EXPORT_SYMBOL(s3c2410_dma_getposition);
+
+/* s3c2410_request_dma
+ *
+ * get control of an dma channel
+*/
+
+int s3c2410_dma_request(unsigned int channel,
+			struct s3c2410_dma_client *client,
+			void *dev)
+{
+	struct s3c2410_dma_chan *chan;
+	unsigned long flags;
+
+	pr_debug("dma%d: s3c2410_request_dma: client=%s, dev=%p\n",
+		 channel, client->name, dev);
+
+	local_irq_save(flags);
+
+	chan = s3c64xx_dma_map_channel(channel);
+	if (chan == NULL) {
+		local_irq_restore(flags);
+		return -EBUSY;
+	}
+
+	dbg_showchan(chan);
+
+	chan->client = client;
+	chan->in_use = 1;
+	chan->peripheral = channel;
+
+	local_irq_restore(flags);
+
+	/* need to setup */
+
+	pr_debug("%s: channel initialised, %p\n", __func__, chan);
+
+	return chan->number | DMACH_LOW_LEVEL;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_request);
+
+/* s3c2410_dma_free
+ *
+ * release the given channel back to the system, will stop and flush
+ * any outstanding transfers, and ensure the channel is ready for the
+ * next claimant.
+ *
+ * Note, although a warning is currently printed if the freeing client
+ * info is not the same as the registrant's client info, the free is still
+ * allowed to go through.
+*/
+
+int s3c2410_dma_free(unsigned int channel, struct s3c2410_dma_client *client)
+{
+	struct s3c2410_dma_chan *chan = s3c_dma_lookup_channel(channel);
+	unsigned long flags;
+
+	if (chan == NULL)
+		return -EINVAL;
+
+	local_irq_save(flags);
+
+	if (chan->client != client) {
+		printk(KERN_WARNING "dma%d: possible free from different client (channel %p, passed %p)\n",
+		       channel, chan->client, client);
+	}
+
+	/* sort out stopping and freeing the channel */
+
+
+	chan->client = NULL;
+	chan->in_use = 0;
+
+	if (!(channel & DMACH_LOW_LEVEL))
+		s3c_dma_chan_map[channel] = NULL;
+
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+EXPORT_SYMBOL(s3c2410_dma_free);
+
+
+static void s3c64xx_dma_tcirq(struct s3c64xx_dmac *dmac, int offs)
+{
+	struct s3c2410_dma_chan *chan = dmac->channels + offs;
+
+	/* note, we currently do not bother to work out which buffer
+	 * or buffers have been completed since the last tc-irq. */
+
+	if (chan->callback_fn)
+		(chan->callback_fn)(chan, chan->curr->pw, 0, S3C2410_RES_OK);
+}
+
+static void s3c64xx_dma_errirq(struct s3c64xx_dmac *dmac, int offs)
+{
+	printk(KERN_DEBUG "%s: offs %d\n", __func__, offs);
+}
+
+static irqreturn_t s3c64xx_dma_irq(int irq, void *pw)
+{
+	struct s3c64xx_dmac *dmac = pw;
+	u32 tcstat, errstat;
+	u32 bit;
+	int offs;
+
+	tcstat = readl(dmac->regs + PL080_TC_STATUS);
+	errstat = readl(dmac->regs + PL080_ERR_STATUS);
+
+	for (offs = 0, bit = 1; offs < 8; offs++, bit <<= 1) {
+		if (tcstat & bit) {
+			writel(bit, dmac->regs + PL080_TC_CLEAR);
+			s3c64xx_dma_tcirq(dmac, offs);
+		}
+
+		if (errstat & bit) {
+			s3c64xx_dma_errirq(dmac, offs);
+			writel(bit, dmac->regs + PL080_ERR_CLEAR);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static struct sysdev_class dma_sysclass = {
+	.name		= "s3c64xx-dma",
+};
+
+static int s3c64xx_dma_init1(int chno, enum dma_ch chbase,
+			     int irq, unsigned int base)
+{
+	struct s3c2410_dma_chan *chptr = &s3c2410_chans[chno];
+	struct s3c64xx_dmac *dmac;
+	char clkname[16];
+	void __iomem *regs;
+	void __iomem *regptr;
+	int err, ch;
+
+	dmac = kzalloc(sizeof(struct s3c64xx_dmac), GFP_KERNEL);
+	if (!dmac) {
+		printk(KERN_ERR "%s: failed to alloc mem\n", __func__);
+		return -ENOMEM;
+	}
+
+	dmac->sysdev.id = chno / 8;
+	dmac->sysdev.cls = &dma_sysclass;
+
+	err = sysdev_register(&dmac->sysdev);
+	if (err) {
+		printk(KERN_ERR "%s: failed to register sysdevice\n", __func__);
+		goto err_alloc;
+	}
+
+	regs = ioremap(base, 0x200);
+	if (!regs) {
+		printk(KERN_ERR "%s: failed to ioremap()\n", __func__);
+		err = -ENXIO;
+		goto err_dev;
+	}
+
+	snprintf(clkname, sizeof(clkname), "dma%d", dmac->sysdev.id);
+
+	dmac->clk = clk_get(NULL, clkname);
+	if (IS_ERR(dmac->clk)) {
+		printk(KERN_ERR "%s: failed to get clock %s\n", __func__, clkname);
+		err = PTR_ERR(dmac->clk);
+		goto err_map;
+	}
+
+	clk_enable(dmac->clk);
+
+	dmac->regs = regs;
+	dmac->chanbase = chbase;
+	dmac->channels = chptr;
+
+	err = request_irq(irq, s3c64xx_dma_irq, 0, "DMA", dmac);
+	if (err < 0) {
+		printk(KERN_ERR "%s: failed to get irq\n", __func__);
+		goto err_clk;
+	}
+
+	regptr = regs + PL080_Cx_BASE(0);
+
+	for (ch = 0; ch < 8; ch++, chno++, chptr++) {
+		printk(KERN_INFO "%s: registering DMA %d (%p)\n",
+		       __func__, chno, regptr);
+
+		chptr->bit = 1 << ch;
+		chptr->number = chno;
+		chptr->dmac = dmac;
+		chptr->regs = regptr;
+		regptr += PL008_Cx_STRIDE;
+	}
+
+	/* for the moment, permanently enable the controller */
+	writel(PL080_CONFIG_ENABLE, regs + PL080_CONFIG);
+
+	printk(KERN_INFO "PL080: IRQ %d, at %p\n", irq, regs);
+
+	return 0;
+
+err_clk:
+	clk_disable(dmac->clk);
+	clk_put(dmac->clk);
+err_map:
+	iounmap(regs);
+err_dev:
+	sysdev_unregister(&dmac->sysdev);
+err_alloc:
+	kfree(dmac);
+	return err;
+}
+
+static int __init s3c64xx_dma_init(void)
+{
+	int ret;
+
+	printk(KERN_INFO "%s: Registering DMA channels\n", __func__);
+
+	dma_pool = dma_pool_create("DMA-LLI", NULL, 32, 16, 0);
+	if (!dma_pool) {
+		printk(KERN_ERR "%s: failed to create pool\n", __func__);
+		return -ENOMEM;
+	}
+
+	ret = sysdev_class_register(&dma_sysclass);
+	if (ret) {
+		printk(KERN_ERR "%s: failed to create sysclass\n", __func__);
+		return -ENOMEM;
+	}
+
+	/* Set all DMA configuration to be DMA, not SDMA */
+	writel(0xffffff, S3C_SYSREG(0x110));
+
+	/* Register standard DMA controlers */
+	s3c64xx_dma_init1(0, DMACH_UART0, IRQ_DMA0, 0x75000000);
+	s3c64xx_dma_init1(8, DMACH_PCM1_TX, IRQ_DMA1, 0x75100000);
+
+	return 0;
+}
+
+arch_initcall(s3c64xx_dma_init);

arch/arm/plat-s3c64xx/include/plat/dma-plat.h

+/* linux/arch/arm/plat-s3c64xx/include/plat/dma-plat.h
+ *
+ * Copyright 2009 Openmoko, Inc.
+ * Copyright 2009 Simtec Electronics
+ *	Ben Dooks <ben@simtec.co.uk>
+ *	http://armlinux.simtec.co.uk/
+ *
+ * S3C64XX DMA core
+ *
+ * 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.
+*/
+
+#define DMACH_LOW_LEVEL (1<<28) /* use this to specifiy hardware ch no */
+
+struct s3c64xx_dma_buff;
+
+/** s3c64xx_dma_buff - S3C64XX DMA buffer descriptor
+ * @next: Pointer to next buffer in queue or ring.
+ * @pw: Client provided identifier
+ * @lli: Pointer to hardware descriptor this buffer is associated with.
+ * @lli_dma: Hardare address of the descriptor.
+ */
+struct s3c64xx_dma_buff {
+	struct s3c64xx_dma_buff *next;
+
+	void			*pw;
+	struct pl080_lli	*lli;
+	dma_addr_t		 lli_dma;
+};
+
+struct s3c64xx_dmac;
+
+struct s3c2410_dma_chan {
+	unsigned char		 number;      /* number of this dma channel */
+	unsigned char		 in_use;      /* channel allocated */
+	unsigned char		 bit;	      /* bit for enable/disable/etc */
+	unsigned char		 hw_width;
+	unsigned char		 peripheral;
+
+	unsigned int		 flags;
+	enum s3c2410_dmasrc	 source;
+
+
+	dma_addr_t		dev_addr;
+
+	struct s3c2410_dma_client *client;
+	struct s3c64xx_dmac	*dmac;		/* pointer to controller */
+
+	void __iomem		*regs;
+
+	/* cdriver callbacks */
+	s3c2410_dma_cbfn_t	 callback_fn;	/* buffer done callback */
+	s3c2410_dma_opfn_t	 op_fn;		/* channel op callback */
+
+	/* buffer list and information */
+	struct s3c64xx_dma_buff	*curr;		/* current dma buffer */
+	struct s3c64xx_dma_buff	*next;		/* next buffer to load */
+	struct s3c64xx_dma_buff	*end;		/* end of queue */
+
+	/* note, when channel is running in circular mode, curr is the
+	 * first buffer enqueued, end is the last and curr is where the
+	 * last buffer-done event is set-at. The buffers are not freed
+	 * and the last buffer hardware descriptor points back to the
+	 * first.
+	 */
+};
+
+#include <plat/dma-core.h>