[PATCH v3] dmaengine: sh: Add Support SuperH DMA Engine driver

[PATCH v3] dmaengine: sh: Add Support SuperH DMA Engine driver

[Nobuhiro Iwamatsu]

This supported all DMA channels, and it was tested in SH7722,
SH7780 and SH7763.
This can not use with SH DMA API.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
Reviewed-by: Matt Fleming <matt@console-pimps.org>
---

 V3: Reflect Maciej's comments.

 arch/sh/drivers/dma/Kconfig  |   12 +-
 arch/sh/drivers/dma/Makefile |    3 +-
 arch/sh/include/asm/dma-sh.h |   13 +
 drivers/dma/Kconfig          |    8 +
 drivers/dma/Makefile         |    2 +
 drivers/dma/shdma.c          |  756 ++++++++++++++++++++++++++++++++++++++++++
 drivers/dma/shdma.h          |   64 ++++
 7 files changed, 853 insertions(+), 5 deletions(-)
 create mode 100644 drivers/dma/shdma.c
 create mode 100644 drivers/dma/shdma.h

diff --git a/arch/sh/drivers/dma/Kconfig b/arch/sh/drivers/dma/Kconfig
index f13a052..ca2ed85 100644
--- a/arch/sh/drivers/dma/Kconfig
+++ b/arch/sh/drivers/dma/Kconfig
@@ -1,12 +1,9 @@
 menu "DMA support"

-config SH_DMA_API
-	bool

 config SH_DMA
 	bool "SuperH on-chip DMA controller (DMAC) support"
 	depends on CPU_SH3 || CPU_SH4
-	select SH_DMA_API
 	default n

 config SH_DMA_IRQ_MULTI
@@ -17,6 +14,15 @@ config SH_DMA_IRQ_MULTI
 		CPU_SUBTYPE_SH7091 || CPU_SUBTYPE_SH7763 || CPU_SUBTYPE_SH7764 || \
 		CPU_SUBTYPE_SH7780 || CPU_SUBTYPE_SH7785

+config SH_DMA_API
+	depends on SH_DMA
+	bool "SuperH DMA API support"
+	default n
+	help
+	  SH_DMA_API always enabled DMA API of used SuperH.
+	  If you want to use DMA ENGINE, you must not enable this.
+	  Please enable DMA_ENGINE and SH_DMAE.
+
 config NR_ONCHIP_DMA_CHANNELS
 	int
 	depends on SH_DMA
diff --git a/arch/sh/drivers/dma/Makefile b/arch/sh/drivers/dma/Makefile
index c606813..d88c948 100644
--- a/arch/sh/drivers/dma/Makefile
+++ b/arch/sh/drivers/dma/Makefile
@@ -2,8 +2,7 @@
 # Makefile for the SuperH DMA specific kernel interface routines under Linux.
 #

-obj-$(CONFIG_SH_DMA_API)	+= dma-api.o dma-sysfs.o
-obj-$(CONFIG_SH_DMA)		+= dma-sh.o
+obj-$(CONFIG_SH_DMA_API)	+= dma-sh.o dma-api.o dma-sysfs.o
 obj-$(CONFIG_PVR2_DMA)		+= dma-pvr2.o
 obj-$(CONFIG_G2_DMA)		+= dma-g2.o
 obj-$(CONFIG_SH_DMABRG)		+= dmabrg.o
diff --git a/arch/sh/include/asm/dma-sh.h b/arch/sh/include/asm/dma-sh.h
index 0c8f8e1..3ade8ea 100644
--- a/arch/sh/include/asm/dma-sh.h
+++ b/arch/sh/include/asm/dma-sh.h
@@ -115,4 +115,17 @@ static u32 dma_base_addr[] __maybe_unused = {
 #define CHCR    0x0C
 #define DMAOR	0x40

+/*
+ * for dma engine
+ *
+ * SuperH DMA mode
+ */
+#define SHDMA_MIX_IRQ	(1 << 1)
+#define SHDMA_DMAOR1	(1 << 2)
+#define SHDMA_DMAE1		(1 << 3)
+
+struct sh_dmae_pdata {
+	unsigned int mode;
+};
+
 #endif /* __DMA_SH_H */
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 7f9e1ec..f8bfde2 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -81,6 +81,14 @@ config MX3_IPU_IRQS
 	  To avoid bloating the irq_desc[] array we allocate a sufficient
 	  number of IRQ slots and map them dynamically to specific sources.

+config SH_DMAE
+	tristate "Renesas SuperH DMAC support"
+	depends on SUPERH && SH_DMA
+	depends on !SH_DMA_API
+	select DMA_ENGINE
+	help
+	  Enable support for the Renesas SuperH DMA controllers.
+
 config DMA_ENGINE
 	bool

diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index 2e5dc96..0d2f3e9 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -8,3 +8,5 @@ obj-$(CONFIG_FSL_DMA) += fsldma.o
 obj-$(CONFIG_MV_XOR) += mv_xor.o
 obj-$(CONFIG_DW_DMAC) += dw_dmac.o
 obj-$(CONFIG_MX3_IPU) += ipu/
+obj-$(CONFIG_SH_DMAE) += shdma.o
+
diff --git a/drivers/dma/shdma.c b/drivers/dma/shdma.c
new file mode 100644
index 0000000..5b12490
--- /dev/null
+++ b/drivers/dma/shdma.c
@@ -0,0 +1,756 @@
+/*
+ * Renesas SuperH DMA Engine support
+ *
+ * base is drivers/dma/flsdma.c
+ *
+ * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
+ * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
+ * Copyright (C) 2007 Freescale Semiconductor, Inc. All rights reserved.
+ *
+ * This 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.
+ *
+ * - DMA of SuperH does not have Hardware DMA chain mode.
+ * - MAX DMA size is 16MB.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/dmaengine.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/platform_device.h>
+#include <cpu/dma.h>
+#include <asm/dma-sh.h>
+#include "shdma.h"
+
+/* DMA descriptor control */
+#define DESC_LAST	(-1)
+#define DESC_COMP	(1)
+#define DESC_NCOMP	(0)
+
+/*
+ * Define the default configuration for dual address memory-memory transfer.
+ * The 0x400 value represents auto-request, external->external.
+ */
+#define RS_DEFAULT RS_DUAL
+
+#define SH_DMAC_CHAN_BASE(id) (dma_base_addr[id])
+static void sh_dmae_writel(struct sh_dmae_chan *sh_dc, u32 data, u32 reg)
+{
+	ctrl_outl(data, (SH_DMAC_CHAN_BASE(sh_dc->id) + reg));
+}
+
+static u32 sh_dmae_readl(struct sh_dmae_chan *sh_dc, u32 reg)
+{
+	return ctrl_inl((SH_DMAC_CHAN_BASE(sh_dc->id) + reg));
+}
+
+static void sh_dmae_writew(struct sh_dmae_chan *sh_dc, u16 data, u32 reg)
+{
+	ctrl_outw(data, (SH_DMAC_CHAN_BASE(sh_dc->id) + reg));
+}
+
+static u16 sh_dmae_readw(struct sh_dmae_chan *sh_dc, u32 reg)
+{
+	return ctrl_inw((SH_DMAC_CHAN_BASE(sh_dc->id) + reg));
+}
+
+static void dmae_init(struct sh_dmae_chan *sh_chan)
+{
+	u32 chcr = RS_DEFAULT; /* default is DUAL mode */
+	sh_dmae_writel(sh_chan, chcr, CHCR);
+}
+
+/*
+ * Reset DMA controller
+ *
+ * SH7780 has two DMAOR register
+ */
+static void sh_dmae_ctl_stop(int id)
+{
+	unsigned short dmaor = dmaor_read_reg(id);
+
+	dmaor &= ~(DMAOR_NMIF | DMAOR_AE);
+	dmaor_write_reg(id, dmaor);
+}
+
+static int sh_dmae_rst(int id)
+{
+	unsigned short dmaor;
+
+	sh_dmae_ctl_stop(id);
+	dmaor = (dmaor_read_reg(id)|DMAOR_INIT);
+
+	dmaor_write_reg(id, dmaor);
+	if ((dmaor_read_reg(id) & (DMAOR_AE | DMAOR_NMIF))) {
+		pr_warning(KERN_ERR "dma-sh: Can't initialize DMAOR.\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int dmae_is_idle(struct sh_dmae_chan *sh_chan)
+{
+	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
+	if (chcr & CHCR_DE) {
+		if (!(chcr & CHCR_TE))
+			return -EBUSY; /* working */
+	}
+	return 0; /* waiting */
+}
+
+static inline unsigned int calc_xmit_shift(struct sh_dmae_chan *sh_chan)
+{
+	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
+	return ts_shift[(chcr & CHCR_TS_MASK) >> CHCR_TS_SHIFT];
+}
+
+static void dmae_set_reg(struct sh_dmae_chan *sh_chan, struct sh_dmae_regs hw)
+{
+	sh_dmae_writel(sh_chan, hw.sar, SAR);
+	sh_dmae_writel(sh_chan, hw.dar, DAR);
+	sh_dmae_writel(sh_chan, hw.tcr, TCR);
+}
+
+static void dmae_start(struct sh_dmae_chan *sh_chan)
+{
+	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
+
+	chcr |= (CHCR_DE|CHCR_IE);
+	sh_dmae_writel(sh_chan, chcr, CHCR);
+}
+
+static void dmae_halt(struct sh_dmae_chan *sh_chan)
+{
+	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
+
+	chcr &= ~(CHCR_DE | CHCR_TE | CHCR_IE);
+	sh_dmae_writel(sh_chan, chcr, CHCR);
+}
+
+static int dmae_set_chcr(struct sh_dmae_chan *sh_chan, u32 val)
+{
+	int ret = dmae_is_idle(sh_chan);
+	/* When DMA was working, can not set data to CHCR */
+	if (ret)
+		return ret;
+	sh_dmae_writel(sh_chan, val, CHCR);
+	return 0;
+}
+
+#define DMARS1_ADDR	0x04
+#define DMARS2_ADDR	0x08
+#define DMARS_SHIFT 8
+#define DMARS_CHAN_MSK 0x01
+static int dmae_set_dmars(struct sh_dmae_chan *sh_chan, u16 val)
+{
+	u32 addr;
+	u16 dmars;
+	int shift = 0;
+	int ret = dmae_is_idle(sh_chan);
+	if (ret)
+		return ret;
+
+	if (sh_chan->id & DMARS_CHAN_MSK)
+		shift = DMARS_SHIFT;
+
+	switch (sh_chan->id) {
+	/* DMARS0 */
+	case 0:
+	case 1:
+		addr = SH_DMARS_BASE;
+		break;
+	/* DMARS1 */
+	case 2:
+	case 3:
+		addr = (SH_DMARS_BASE + DMARS1_ADDR);
+		break;
+	/* DMARS2 */
+	case 4:
+	case 5:
+		addr = (SH_DMARS_BASE + DMARS2_ADDR);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	dmars = sh_dmae_readw(sh_chan, addr);
+	sh_dmae_writew(sh_chan,
+		(val << shift) | (dmars & (shift ? 0xFF00 : 0x00FF)),
+		addr);
+	return 0;
+}
+
+static dma_cookie_t sh_dmae_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	struct sh_desc *desc = tx_to_sh_desc(tx);
+	struct sh_dmae_chan *sh_chan = to_sh_chan(tx->chan);
+	unsigned long flags;
+	dma_cookie_t cookie;
+
+	spin_lock_irqsave(&sh_chan->desc_lock, flags);
+
+	cookie = sh_chan->common.cookie;
+	cookie++;
+	if (cookie < 0)
+		cookie = 1;
+
+	/* If desc only in the case of 1 */
+	if (desc->async_tx.cookie != -EBUSY)
+		desc->async_tx.cookie = cookie;
+	sh_chan->common.cookie = desc->async_tx.cookie;
+
+	list_splice_init(&desc->async_tx.tx_list, sh_chan->ld_queue.prev);
+
+	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
+
+	return cookie;
+}
+
+static struct sh_desc *sh_dmae_alloc_descriptor(struct sh_dmae_chan *sh_chan)
+{
+	struct sh_desc *desc_sw;
+	desc_sw = kzalloc(sizeof(struct sh_desc), GFP_KERNEL);
+	if (desc_sw) {
+		dma_async_tx_descriptor_init(&desc_sw->async_tx,
+						&sh_chan->common);
+		desc_sw->async_tx.tx_submit = sh_dmae_tx_submit;
+		INIT_LIST_HEAD(&desc_sw->async_tx.tx_list);
+	}
+
+	return desc_sw;
+}
+
+static int sh_dmae_alloc_chan_resources(struct dma_chan *chan)
+{
+	return 1;
+}
+
+/*
+ * sh_dma_free_chan_resources - Free all resources of the channel.
+ */
+static void sh_dmae_free_chan_resources(struct dma_chan *chan)
+{
+	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
+	struct sh_desc *desc, *_desc;
+	unsigned long flags;
+
+	dev_dbg(sh_chan->dev, "Free all channel resources.\n");
+	spin_lock_irqsave(&sh_chan->desc_lock, flags);
+	list_for_each_entry_safe(desc, _desc, &sh_chan->ld_queue, node) {
+		list_del(&desc->node);
+		/* free link descriptor */
+		kfree(desc);
+	}
+	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
+}
+
+static struct dma_async_tx_descriptor *sh_dmae_prep_memcpy(
+	struct dma_chan *chan, dma_addr_t dma_dest, dma_addr_t dma_src,
+	size_t len, unsigned long flags)
+{
+	struct sh_dmae_chan *sh_chan;
+	struct sh_desc *first = NULL, *prev = NULL, *new;
+	size_t copy_size;
+	int cnt = 0;
+	LIST_HEAD(link_chain);
+
+	if (!chan)
+		return NULL;
+
+	if (!len)
+		return NULL;
+
+	sh_chan = to_sh_chan(chan);
+
+	do {
+		/* Allocate the link descriptor from DMA pool */
+		new = sh_dmae_alloc_descriptor(sh_chan);
+		if (!new) {
+			dev_err(sh_chan->dev,
+					"No free memory for link descriptor\n");
+			return NULL;
+		}
+
+		copy_size = min(len, (size_t)SH_DMA_TCR_MAX);
+
+		new->hw.sar = dma_src;
+		new->hw.dar = dma_dest;
+		new->hw.tcr = (copy_size >> calc_xmit_shift(sh_chan));
+		if (!first)
+			first = new;
+
+		new->mark = DESC_NCOMP;
+		async_tx_ack(&new->async_tx);
+
+		prev = new;
+		len -= copy_size;
+		dma_src += copy_size;
+		dma_dest += copy_size;
+		cnt++;
+		/* Insert the link descriptor to the LD ring */
+		list_add_tail(&new->node, &first->async_tx.tx_list);
+	} while (len);
+
+	new->async_tx.flags = flags; /* client is in control of this ack */
+	new->async_tx.cookie = -EBUSY;
+
+	return first ? &first->async_tx : NULL;
+}
+
+
+
+/*
+ * sh_chan_ld_cleanup - Clean up link descriptors
+ *
+ * This function clean up the ld_queue of DMA channel.
+ */
+static void sh_dmae_chan_ld_cleanup(struct sh_dmae_chan *sh_chan)
+{
+	struct sh_desc *desc, *_desc;
+	unsigned long flags;
+
+	spin_lock_irqsave(&sh_chan->desc_lock, flags);
+	list_for_each_entry_safe(desc, _desc, &sh_chan->ld_queue, node) {
+		dma_async_tx_callback callback;
+		void *callback_param;
+
+		/* non send data */
+		if (desc->mark = DESC_NCOMP)
+			break;
+
+		/* send data sesc */
+		callback = desc->async_tx.callback;
+		callback_param = desc->async_tx.callback_param;
+
+		/* Remove from ld_queue list */
+		list_del(&desc->node);
+
+		dev_dbg(sh_chan->dev, "link descriptor %p will be recycle.\n",
+				desc);
+		kfree(desc);
+		/* Run the link descriptor callback function */
+		if (callback) {
+			spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
+			dev_dbg(sh_chan->dev, "link descriptor %p callback\n",
+					desc);
+			callback(callback_param);
+			spin_lock_irqsave(&sh_chan->desc_lock, flags);
+		}
+	}
+	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
+}
+
+static void sh_chan_xfer_ld_queue(struct sh_dmae_chan *sh_chan)
+{
+	struct list_head *ld_node;
+	unsigned long flags;
+	struct sh_dmae_regs hw;
+
+	if (dmae_is_idle(sh_chan))
+		return;
+
+	dmae_halt(sh_chan);
+	spin_lock_irqsave(&sh_chan->desc_lock, flags);
+
+	/* Find the first un-transfer desciptor */
+	for (ld_node = sh_chan->ld_queue.next;
+		(ld_node != &sh_chan->ld_queue)
+			&& (to_sh_desc(ld_node)->mark = DESC_COMP);
+		ld_node = ld_node->next)
+		cpu_relax();
+
+	if (ld_node != &sh_chan->ld_queue) {
+		/* Get the ld start address from ld_queue */
+		hw = to_sh_desc(ld_node)->hw;
+		dmae_set_reg(sh_chan, hw);
+		dmae_start(sh_chan);
+	}
+	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
+}
+
+static void sh_dmae_memcpy_issue_pending(struct dma_chan *chan)
+{
+	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
+
+	sh_chan_xfer_ld_queue(sh_chan);
+}
+
+static enum dma_status sh_dmae_is_complete(struct dma_chan *chan,
+					dma_cookie_t cookie,
+					dma_cookie_t *done,
+					dma_cookie_t *used)
+{
+	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
+	dma_cookie_t last_used;
+	dma_cookie_t last_complete;
+
+	sh_dmae_chan_ld_cleanup(sh_chan);
+
+	last_used = chan->cookie;
+	last_complete = sh_chan->completed_cookie;
+	if (last_complete = -EBUSY)
+		last_complete = last_used;
+
+	if (done)
+		*done = last_complete;
+
+	if (used)
+		*used = last_used;
+
+	return dma_async_is_complete(cookie, last_complete, last_used);
+}
+
+static irqreturn_t sh_dmae_interrupt(int irq, void *data)
+{
+	irqreturn_t ret = IRQ_NONE;
+	struct sh_dmae_chan *sh_chan = (struct sh_dmae_chan *)data;
+	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
+
+	if (chcr & CHCR_TE) {
+		unsigned long flags;
+		struct sh_desc *desc, *_desc, *cur_desc = NULL;
+		u32 sar_buf = sh_dmae_readl(sh_chan, SAR);
+
+		spin_lock_irqsave(&sh_chan->desc_lock, flags);
+		list_for_each_entry_safe(desc, _desc,
+						&sh_chan->ld_queue, node) {
+			if ((desc->hw.sar + desc->hw.tcr) = sar_buf) {
+				cur_desc = desc;
+				break;
+			}
+		}
+		spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
+
+		if (cur_desc) {
+			switch (cur_desc->async_tx.cookie) {
+			case 0: /* other desc data */
+				break;
+			case -EBUSY: /* last desc */
+				sh_chan->completed_cookie +					cur_desc->async_tx.cookie;
+				break;
+			default: /* first desc ( 0 < )*/
+				sh_chan->completed_cookie +					cur_desc->async_tx.cookie - 1;
+				break;
+			}
+			cur_desc->mark = DESC_COMP;
+		}
+		/* Next desc */
+		sh_chan_xfer_ld_queue(sh_chan);
+		ret = IRQ_HANDLED;
+	}
+	tasklet_schedule(&sh_chan->tasklet);
+
+	return ret;
+}
+
+#if defined(CONFIG_CPU_SH4)
+static irqreturn_t sh_dmae_err(int irq, void *data)
+{
+	int err = 0;
+	struct sh_dmae_device *shdev = (struct sh_dmae_device *)data;
+
+	/* IRQ Multi */
+	if (shdev->pdata.mode & SHDMA_MIX_IRQ) {
+		int cnt = 0;
+		switch (irq) {
+#if defined(DMTE6_IRQ) && defined(DMAE1_IRQ)
+		case DMTE6_IRQ:
+			cnt++;
+#endif
+		case DMTE0_IRQ:
+			if (dmaor_read_reg(cnt) & (DMAOR_NMIF | DMAOR_AE)) {
+				disable_irq(irq);
+				return IRQ_HANDLED;
+			}
+		default:
+			return IRQ_NONE;
+		}
+	} else {
+		/* reset dma controller */
+		err = sh_dmae_rst(0);
+		if (err)
+			return err;
+		if (shdev->pdata.mode & SHDMA_DMAOR1) {
+			err = sh_dmae_rst(1);
+			if (err)
+				return err;
+		}
+		disable_irq(irq);
+		return IRQ_HANDLED;
+	}
+}
+#endif
+
+static void dmae_do_tasklet(unsigned long data)
+{
+	struct sh_dmae_chan *sh_chan = (struct sh_dmae_chan *)data;
+	sh_dmae_chan_ld_cleanup(sh_chan);
+}
+
+static unsigned int get_dmae_irq(unsigned int id)
+{
+	unsigned int irq = 0;
+	if (id < ARRAY_SIZE(dmte_irq_map))
+		irq = dmte_irq_map[id];
+	return irq;
+}
+
+static int __devinit sh_dmae_chan_probe(struct sh_dmae_device *shdev, int id)
+{
+	int err;
+	unsigned int irq = get_dmae_irq(id);
+	unsigned long irqflags = IRQF_DISABLED;
+	struct sh_dmae_chan *new_sh_chan;
+
+	/* alloc channel */
+	new_sh_chan = kzalloc(sizeof(struct sh_dmae_chan), GFP_KERNEL);
+	if (!new_sh_chan) {
+		dev_err(shdev->common.dev, "No free memory for allocating "
+				"dma channels!\n");
+		return -ENOMEM;
+	}
+
+	new_sh_chan->dev = shdev->common.dev;
+	shdev->chan[id] = new_sh_chan;
+	new_sh_chan->id = id;
+
+	/* Init DMA tasklet */
+	tasklet_init(&new_sh_chan->tasklet, dmae_do_tasklet,
+			(unsigned long)new_sh_chan);
+
+	/* Init the channel */
+	dmae_init(new_sh_chan);
+
+	spin_lock_init(&new_sh_chan->desc_lock);
+
+	/* Init descripter manage list */
+	INIT_LIST_HEAD(&new_sh_chan->ld_queue);
+
+	/* copy struct dma_device */
+	new_sh_chan->common.device = &shdev->common;
+
+	/* Add the channel to DMA device channel list */
+	list_add_tail(&new_sh_chan->common.device_node,
+			&shdev->common.channels);
+	shdev->common.chancnt++;
+
+	if (shdev->pdata.mode & SHDMA_MIX_IRQ) {
+		irqflags = IRQF_SHARED;
+#if defined(DMTE6_IRQ)
+		if (irq >= DMTE6_IRQ)
+			irq = DMTE6_IRQ;
+		else
+#endif
+			irq = DMTE0_IRQ;
+	}
+
+	snprintf(new_sh_chan->dev_id, sizeof(new_sh_chan->dev_id),
+			"sh-dmae%d", new_sh_chan->id);
+
+	/* set up channel irq */
+	err = request_irq(irq, &sh_dmae_interrupt,
+		irqflags, new_sh_chan->dev_id, new_sh_chan);
+	if (err) {
+		dev_err(shdev->common.dev, "DMA channel %d request_irq error "
+			"with return %d\n", id, err);
+		goto err_no_irq;
+	}
+
+	/* CHCR register control function */
+	new_sh_chan->set_chcr = dmae_set_chcr;
+	/* DMARS register control function */
+	new_sh_chan->set_dmars = dmae_set_dmars;
+
+	return 0;
+
+err_no_irq:
+	/* remove from dmaengine device node */
+	list_del(&new_sh_chan->common.device_node);
+	kfree(new_sh_chan);
+	return err;
+}
+
+static void sh_dmae_chan_remove(struct sh_dmae_device *shdev)
+{
+	int i;
+
+	for (i = shdev->common.chancnt - 1 ; i >= 0 ; i--) {
+		if (shdev->chan[i]) {
+			struct sh_dmae_chan *shchan = shdev->chan[i];
+			if (!(shdev->pdata.mode & SHDMA_MIX_IRQ))
+				free_irq(dmte_irq_map[i], shchan);
+
+			list_del(&shchan->common.device_node);
+			kfree(shchan);
+			shdev->chan[i] = NULL;
+		}
+	}
+	shdev->common.chancnt = 0;
+}
+
+static int __init sh_dmae_probe(struct platform_device *pdev)
+{
+	int err = 0, cnt, ecnt;
+	unsigned long irqflags = IRQF_DISABLED;
+#if defined(CONFIG_CPU_SH4)
+	int eirq[] = { DMAE0_IRQ,
+#if defined(DMAE1_IRQ)
+			DMAE1_IRQ
+#endif
+		};
+#endif
+	struct sh_dmae_device *shdev;
+
+	shdev = kzalloc(sizeof(struct sh_dmae_device), GFP_KERNEL);
+	if (!shdev) {
+		dev_err(&pdev->dev, "No enough memory\n");
+		err = -ENOMEM;
+		goto shdev_err;
+	}
+
+	/* get platform data */
+	if (!pdev->dev.platform_data)
+		goto shdev_err;
+
+	/* platform data */
+	memcpy(&shdev->pdata, pdev->dev.platform_data,
+			sizeof(struct sh_dmae_pdata));
+
+	/* reset dma controller */
+	err = sh_dmae_rst(0);
+	if (err)
+		goto rst_err;
+
+	/* SH7780/85/23 has DMAOR1 */
+	if (shdev->pdata.mode & SHDMA_DMAOR1) {
+		err = sh_dmae_rst(1);
+		if (err)
+			goto rst_err;
+	}
+
+	INIT_LIST_HEAD(&shdev->common.channels);
+
+	dma_cap_set(DMA_MEMCPY, shdev->common.cap_mask);
+	shdev->common.device_alloc_chan_resources
+		= sh_dmae_alloc_chan_resources;
+	shdev->common.device_free_chan_resources = sh_dmae_free_chan_resources;
+	shdev->common.device_prep_dma_memcpy = sh_dmae_prep_memcpy;
+	shdev->common.device_is_tx_complete = sh_dmae_is_complete;
+	shdev->common.device_issue_pending = sh_dmae_memcpy_issue_pending;
+	shdev->common.dev = &pdev->dev;
+
+#if defined(CONFIG_CPU_SH4)
+	/* Non Mix IRQ mode SH7722/SH7730 etc... */
+	if (shdev->pdata.mode & SHDMA_MIX_IRQ) {
+		irqflags = IRQF_SHARED;
+		eirq[0] = DMTE0_IRQ;
+#if defined(DMTE6_IRQ) && defined(DMAE1_IRQ)
+		eirq[1] = DMTE6_IRQ;
+#endif
+	}
+
+	for (ecnt = 0 ; ecnt < ARRAY_SIZE(eirq); ecnt++) {
+		err = request_irq(eirq[ecnt], sh_dmae_err,
+			irqflags, "DMAC Address Error", shdev);
+		if (err) {
+			dev_err(&pdev->dev, "DMA device request_irq"
+				"erro (irq %d) with return %d\n",
+				eirq[ecnt], err);
+			goto eirq_err;
+		}
+	}
+#endif /* CONFIG_CPU_SH4 */
+
+	/* Create DMA Channel */
+	for (cnt = 0 ; cnt < MAX_DMA_CHANNELS ; cnt++) {
+		err = sh_dmae_chan_probe(shdev, cnt);
+		if (err)
+			goto chan_probe_err;
+	}
+
+	platform_set_drvdata(pdev, shdev);
+	dma_async_device_register(&shdev->common);
+
+	return err;
+
+chan_probe_err:
+	sh_dmae_chan_remove(shdev);
+
+eirq_err:
+	for (ecnt-- ; ecnt >= 0; ecnt--)
+		free_irq(eirq[ecnt], shdev);
+
+rst_err:
+	kfree(shdev);
+
+shdev_err:
+	return err;
+}
+
+static int __exit sh_dmae_remove(struct platform_device *pdev)
+{
+	struct sh_dmae_device *shdev = platform_get_drvdata(pdev);
+
+	dma_async_device_unregister(&shdev->common);
+
+	if (shdev->pdata.mode & SHDMA_MIX_IRQ) {
+		free_irq(DMTE0_IRQ, shdev);
+#if defined(DMTE6_IRQ)
+		free_irq(DMTE6_IRQ, shdev);
+#endif
+	}
+
+	/* channel data remove */
+	sh_dmae_chan_remove(shdev);
+
+	if (!(shdev->pdata.mode & SHDMA_MIX_IRQ)) {
+		free_irq(DMAE0_IRQ, shdev);
+#if defined(DMAE1_IRQ)
+		free_irq(DMAE1_IRQ, shdev);
+#endif
+	}
+	kfree(shdev);
+
+	return 0;
+}
+
+static void sh_dmae_shutdown(struct platform_device *pdev)
+{
+	struct sh_dmae_device *shdev = platform_get_drvdata(pdev);
+	sh_dmae_ctl_stop(0);
+	if (shdev->pdata.mode & SHDMA_DMAOR1)
+		sh_dmae_ctl_stop(1);
+}
+
+static struct platform_driver sh_dmae_driver = {
+	.remove		= __exit_p(sh_dmae_remove),
+	.shutdown	= sh_dmae_shutdown,
+	.driver = {
+		.name	= "sh-dma-engine",
+	},
+};
+
+static int __init sh_dmae_init(void)
+{
+	return platform_driver_probe(&sh_dmae_driver, sh_dmae_probe);
+}
+module_init(sh_dmae_init);
+
+static void __exit sh_dmae_exit(void)
+{
+	platform_driver_unregister(&sh_dmae_driver);
+}
+module_exit(sh_dmae_exit);
+
+MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>");
+MODULE_DESCRIPTION("Renesas SH DMA Engine driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/dma/shdma.h b/drivers/dma/shdma.h
new file mode 100644
index 0000000..ebb4a9f
--- /dev/null
+++ b/drivers/dma/shdma.h
@@ -0,0 +1,64 @@
+/*
+ * Renesas SuperH DMA Engine support
+ *
+ * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
+ * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
+ *
+ * This 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.
+ *
+ */
+#ifndef __DMA_SHDMA_H
+#define __DMA_SHDMA_H
+
+#include <linux/device.h>
+#include <linux/dmapool.h>
+#include <linux/dmaengine.h>
+
+#define SH_DMA_TCR_MAX 0x00FFFFFF	/* 16MB */
+
+struct sh_dmae_regs {
+	u32 sar; /* SAR / source address */
+	u32 dar; /* DAR / destination address */
+	u32 tcr; /* TCR / transfer count */
+};
+
+struct sh_desc {
+	struct sh_dmae_regs hw;
+	struct list_head node;
+	struct dma_async_tx_descriptor async_tx;
+	struct list_head *ld;
+	int mark;
+};
+
+struct sh_dmae_chan {
+	dma_cookie_t completed_cookie;	/* The maximum cookie completed */
+	spinlock_t desc_lock;			/* Descriptor operation lock */
+	struct list_head ld_queue;		/* Link descriptors queue */
+	struct dma_chan common;			/* DMA common channel */
+	struct device *dev;				/* Channel device */
+	struct resource reg;			/* Resource for register */
+	struct tasklet_struct tasklet;
+	int id;	/* Raw id of this channel */
+	char dev_id[16];	/* unique name per DMAC of channel */
+
+	/* Set chcr */
+	int (*set_chcr)(struct sh_dmae_chan *sh_chan, u32 regs);
+	/* Set DMA resource */
+	int (*set_dmars)(struct sh_dmae_chan *sh_chan, u16 res);
+};
+
+struct sh_dmae_device {
+	struct resource reg;	/* Resource for register */
+	struct dma_device common;
+	struct sh_dmae_chan *chan[MAX_DMA_CHANNELS];
+	struct sh_dmae_pdata pdata;
+};
+
+#define to_sh_chan(chan) container_of(chan, struct sh_dmae_chan, common)
+#define to_sh_desc(lh) container_of(lh, struct sh_desc, node)
+#define tx_to_sh_desc(tx) container_of(tx, struct sh_desc, async_tx)
+
+#endif	/* __DMA_SHDMA_H */
-- 
1.6.2.1

Re: [PATCH v3] dmaengine: sh: Add Support SuperH DMA Engine driver

[Paul Mundt]

On Wed, Mar 25, 2009 at 03:55:20PM +0900, Nobuhiro Iwamatsu wrote:
> This supported all DMA channels, and it was tested in SH7722,
> SH7780 and SH7763.
> This can not use with SH DMA API.
> 
> Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
> Reviewed-by: Matt Fleming <matt@console-pimps.org>

I don't know why you dropped Dan from the CC, but you need his Acked-by
or Reviewed-by before this can be merged.

> ---
> 
>  V3: Reflect Maciej's comments.
> 
>  arch/sh/drivers/dma/Kconfig  |   12 +-
>  arch/sh/drivers/dma/Makefile |    3 +-
>  arch/sh/include/asm/dma-sh.h |   13 +
>  drivers/dma/Kconfig          |    8 +
>  drivers/dma/Makefile         |    2 +
>  drivers/dma/shdma.c          |  756 ++++++++++++++++++++++++++++++++++++++++++
>  drivers/dma/shdma.h          |   64 ++++
>  7 files changed, 853 insertions(+), 5 deletions(-)
>  create mode 100644 drivers/dma/shdma.c
>  create mode 100644 drivers/dma/shdma.h
> 
> diff --git a/arch/sh/drivers/dma/Kconfig b/arch/sh/drivers/dma/Kconfig
> index f13a052..ca2ed85 100644
> --- a/arch/sh/drivers/dma/Kconfig
> +++ b/arch/sh/drivers/dma/Kconfig
> @@ -1,12 +1,9 @@
>  menu "DMA support"
> 
> -config SH_DMA_API
> -	bool
> 
>  config SH_DMA
>  	bool "SuperH on-chip DMA controller (DMAC) support"
>  	depends on CPU_SH3 || CPU_SH4
> -	select SH_DMA_API
>  	default n
> 
>  config SH_DMA_IRQ_MULTI
> @@ -17,6 +14,15 @@ config SH_DMA_IRQ_MULTI
>  		CPU_SUBTYPE_SH7091 || CPU_SUBTYPE_SH7763 || CPU_SUBTYPE_SH7764 || \
>  		CPU_SUBTYPE_SH7780 || CPU_SUBTYPE_SH7785
> 
> +config SH_DMA_API
> +	depends on SH_DMA
> +	bool "SuperH DMA API support"
> +	default n
> +	help
> +	  SH_DMA_API always enabled DMA API of used SuperH.
> +	  If you want to use DMA ENGINE, you must not enable this.
> +	  Please enable DMA_ENGINE and SH_DMAE.
> +
>  config NR_ONCHIP_DMA_CHANNELS
>  	int
>  	depends on SH_DMA
> diff --git a/arch/sh/drivers/dma/Makefile b/arch/sh/drivers/dma/Makefile
> index c606813..d88c948 100644
> --- a/arch/sh/drivers/dma/Makefile
> +++ b/arch/sh/drivers/dma/Makefile
> @@ -2,8 +2,7 @@
>  # Makefile for the SuperH DMA specific kernel interface routines under Linux.
>  #
> 
> -obj-$(CONFIG_SH_DMA_API)	+= dma-api.o dma-sysfs.o
> -obj-$(CONFIG_SH_DMA)		+= dma-sh.o
> +obj-$(CONFIG_SH_DMA_API)	+= dma-sh.o dma-api.o dma-sysfs.o
>  obj-$(CONFIG_PVR2_DMA)		+= dma-pvr2.o
>  obj-$(CONFIG_G2_DMA)		+= dma-g2.o
>  obj-$(CONFIG_SH_DMABRG)		+= dmabrg.o
> diff --git a/arch/sh/include/asm/dma-sh.h b/arch/sh/include/asm/dma-sh.h
> index 0c8f8e1..3ade8ea 100644
> --- a/arch/sh/include/asm/dma-sh.h
> +++ b/arch/sh/include/asm/dma-sh.h
> @@ -115,4 +115,17 @@ static u32 dma_base_addr[] __maybe_unused = {
>  #define CHCR    0x0C
>  #define DMAOR	0x40
> 
> +/*
> + * for dma engine
> + *
> + * SuperH DMA mode
> + */
> +#define SHDMA_MIX_IRQ	(1 << 1)
> +#define SHDMA_DMAOR1	(1 << 2)
> +#define SHDMA_DMAE1		(1 << 3)
> +
> +struct sh_dmae_pdata {
> +	unsigned int mode;
> +};
> +
>  #endif /* __DMA_SH_H */
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index 7f9e1ec..f8bfde2 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -81,6 +81,14 @@ config MX3_IPU_IRQS
>  	  To avoid bloating the irq_desc[] array we allocate a sufficient
>  	  number of IRQ slots and map them dynamically to specific sources.
> 
> +config SH_DMAE
> +	tristate "Renesas SuperH DMAC support"
> +	depends on SUPERH && SH_DMA
> +	depends on !SH_DMA_API
> +	select DMA_ENGINE
> +	help
> +	  Enable support for the Renesas SuperH DMA controllers.
> +
>  config DMA_ENGINE
>  	bool
> 
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index 2e5dc96..0d2f3e9 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -8,3 +8,5 @@ obj-$(CONFIG_FSL_DMA) += fsldma.o
>  obj-$(CONFIG_MV_XOR) += mv_xor.o
>  obj-$(CONFIG_DW_DMAC) += dw_dmac.o
>  obj-$(CONFIG_MX3_IPU) += ipu/
> +obj-$(CONFIG_SH_DMAE) += shdma.o
> +
> diff --git a/drivers/dma/shdma.c b/drivers/dma/shdma.c
> new file mode 100644
> index 0000000..5b12490
> --- /dev/null
> +++ b/drivers/dma/shdma.c
> @@ -0,0 +1,756 @@
> +/*
> + * Renesas SuperH DMA Engine support
> + *
> + * base is drivers/dma/flsdma.c
> + *
> + * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
> + * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
> + * Copyright (C) 2007 Freescale Semiconductor, Inc. All rights reserved.
> + *
> + * This 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.
> + *
> + * - DMA of SuperH does not have Hardware DMA chain mode.
> + * - MAX DMA size is 16MB.
> + *
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/dmaengine.h>
> +#include <linux/delay.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmapool.h>
> +#include <linux/platform_device.h>
> +#include <cpu/dma.h>
> +#include <asm/dma-sh.h>
> +#include "shdma.h"
> +
> +/* DMA descriptor control */
> +#define DESC_LAST	(-1)
> +#define DESC_COMP	(1)
> +#define DESC_NCOMP	(0)
> +
> +/*
> + * Define the default configuration for dual address memory-memory transfer.
> + * The 0x400 value represents auto-request, external->external.
> + */
> +#define RS_DEFAULT RS_DUAL
> +
> +#define SH_DMAC_CHAN_BASE(id) (dma_base_addr[id])
> +static void sh_dmae_writel(struct sh_dmae_chan *sh_dc, u32 data, u32 reg)
> +{
> +	ctrl_outl(data, (SH_DMAC_CHAN_BASE(sh_dc->id) + reg));
> +}
> +
> +static u32 sh_dmae_readl(struct sh_dmae_chan *sh_dc, u32 reg)
> +{
> +	return ctrl_inl((SH_DMAC_CHAN_BASE(sh_dc->id) + reg));
> +}
> +
> +static void sh_dmae_writew(struct sh_dmae_chan *sh_dc, u16 data, u32 reg)
> +{
> +	ctrl_outw(data, (SH_DMAC_CHAN_BASE(sh_dc->id) + reg));
> +}
> +
> +static u16 sh_dmae_readw(struct sh_dmae_chan *sh_dc, u32 reg)
> +{
> +	return ctrl_inw((SH_DMAC_CHAN_BASE(sh_dc->id) + reg));
> +}
> +
> +static void dmae_init(struct sh_dmae_chan *sh_chan)
> +{
> +	u32 chcr = RS_DEFAULT; /* default is DUAL mode */
> +	sh_dmae_writel(sh_chan, chcr, CHCR);
> +}
> +
> +/*
> + * Reset DMA controller
> + *
> + * SH7780 has two DMAOR register
> + */
> +static void sh_dmae_ctl_stop(int id)
> +{
> +	unsigned short dmaor = dmaor_read_reg(id);
> +
> +	dmaor &= ~(DMAOR_NMIF | DMAOR_AE);
> +	dmaor_write_reg(id, dmaor);
> +}
> +
> +static int sh_dmae_rst(int id)
> +{
> +	unsigned short dmaor;
> +
> +	sh_dmae_ctl_stop(id);
> +	dmaor = (dmaor_read_reg(id)|DMAOR_INIT);
> +
> +	dmaor_write_reg(id, dmaor);
> +	if ((dmaor_read_reg(id) & (DMAOR_AE | DMAOR_NMIF))) {
> +		pr_warning(KERN_ERR "dma-sh: Can't initialize DMAOR.\n");
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
> +static int dmae_is_idle(struct sh_dmae_chan *sh_chan)
> +{
> +	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
> +	if (chcr & CHCR_DE) {
> +		if (!(chcr & CHCR_TE))
> +			return -EBUSY; /* working */
> +	}
> +	return 0; /* waiting */
> +}
> +
> +static inline unsigned int calc_xmit_shift(struct sh_dmae_chan *sh_chan)
> +{
> +	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
> +	return ts_shift[(chcr & CHCR_TS_MASK) >> CHCR_TS_SHIFT];
> +}
> +
> +static void dmae_set_reg(struct sh_dmae_chan *sh_chan, struct sh_dmae_regs hw)
> +{
> +	sh_dmae_writel(sh_chan, hw.sar, SAR);
> +	sh_dmae_writel(sh_chan, hw.dar, DAR);
> +	sh_dmae_writel(sh_chan, hw.tcr, TCR);
> +}
> +
> +static void dmae_start(struct sh_dmae_chan *sh_chan)
> +{
> +	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
> +
> +	chcr |= (CHCR_DE|CHCR_IE);
> +	sh_dmae_writel(sh_chan, chcr, CHCR);
> +}
> +
> +static void dmae_halt(struct sh_dmae_chan *sh_chan)
> +{
> +	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
> +
> +	chcr &= ~(CHCR_DE | CHCR_TE | CHCR_IE);
> +	sh_dmae_writel(sh_chan, chcr, CHCR);
> +}
> +
> +static int dmae_set_chcr(struct sh_dmae_chan *sh_chan, u32 val)
> +{
> +	int ret = dmae_is_idle(sh_chan);
> +	/* When DMA was working, can not set data to CHCR */
> +	if (ret)
> +		return ret;
> +	sh_dmae_writel(sh_chan, val, CHCR);
> +	return 0;
> +}
> +
> +#define DMARS1_ADDR	0x04
> +#define DMARS2_ADDR	0x08
> +#define DMARS_SHIFT 8
> +#define DMARS_CHAN_MSK 0x01
> +static int dmae_set_dmars(struct sh_dmae_chan *sh_chan, u16 val)
> +{
> +	u32 addr;
> +	u16 dmars;
> +	int shift = 0;
> +	int ret = dmae_is_idle(sh_chan);
> +	if (ret)
> +		return ret;
> +
> +	if (sh_chan->id & DMARS_CHAN_MSK)
> +		shift = DMARS_SHIFT;
> +
> +	switch (sh_chan->id) {
> +	/* DMARS0 */
> +	case 0:
> +	case 1:
> +		addr = SH_DMARS_BASE;
> +		break;
> +	/* DMARS1 */
> +	case 2:
> +	case 3:
> +		addr = (SH_DMARS_BASE + DMARS1_ADDR);
> +		break;
> +	/* DMARS2 */
> +	case 4:
> +	case 5:
> +		addr = (SH_DMARS_BASE + DMARS2_ADDR);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	dmars = sh_dmae_readw(sh_chan, addr);
> +	sh_dmae_writew(sh_chan,
> +		(val << shift) | (dmars & (shift ? 0xFF00 : 0x00FF)),
> +		addr);
> +	return 0;
> +}
> +
> +static dma_cookie_t sh_dmae_tx_submit(struct dma_async_tx_descriptor *tx)
> +{
> +	struct sh_desc *desc = tx_to_sh_desc(tx);
> +	struct sh_dmae_chan *sh_chan = to_sh_chan(tx->chan);
> +	unsigned long flags;
> +	dma_cookie_t cookie;
> +
> +	spin_lock_irqsave(&sh_chan->desc_lock, flags);
> +
> +	cookie = sh_chan->common.cookie;
> +	cookie++;
> +	if (cookie < 0)
> +		cookie = 1;
> +
> +	/* If desc only in the case of 1 */
> +	if (desc->async_tx.cookie != -EBUSY)
> +		desc->async_tx.cookie = cookie;
> +	sh_chan->common.cookie = desc->async_tx.cookie;
> +
> +	list_splice_init(&desc->async_tx.tx_list, sh_chan->ld_queue.prev);
> +
> +	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
> +
> +	return cookie;
> +}
> +
> +static struct sh_desc *sh_dmae_alloc_descriptor(struct sh_dmae_chan *sh_chan)
> +{
> +	struct sh_desc *desc_sw;
> +	desc_sw = kzalloc(sizeof(struct sh_desc), GFP_KERNEL);
> +	if (desc_sw) {
> +		dma_async_tx_descriptor_init(&desc_sw->async_tx,
> +						&sh_chan->common);
> +		desc_sw->async_tx.tx_submit = sh_dmae_tx_submit;
> +		INIT_LIST_HEAD(&desc_sw->async_tx.tx_list);
> +	}
> +
> +	return desc_sw;
> +}
> +
> +static int sh_dmae_alloc_chan_resources(struct dma_chan *chan)
> +{
> +	return 1;
> +}
> +
> +/*
> + * sh_dma_free_chan_resources - Free all resources of the channel.
> + */
> +static void sh_dmae_free_chan_resources(struct dma_chan *chan)
> +{
> +	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
> +	struct sh_desc *desc, *_desc;
> +	unsigned long flags;
> +
> +	dev_dbg(sh_chan->dev, "Free all channel resources.\n");
> +	spin_lock_irqsave(&sh_chan->desc_lock, flags);
> +	list_for_each_entry_safe(desc, _desc, &sh_chan->ld_queue, node) {
> +		list_del(&desc->node);
> +		/* free link descriptor */
> +		kfree(desc);
> +	}
> +	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
> +}
> +
> +static struct dma_async_tx_descriptor *sh_dmae_prep_memcpy(
> +	struct dma_chan *chan, dma_addr_t dma_dest, dma_addr_t dma_src,
> +	size_t len, unsigned long flags)
> +{
> +	struct sh_dmae_chan *sh_chan;
> +	struct sh_desc *first = NULL, *prev = NULL, *new;
> +	size_t copy_size;
> +	int cnt = 0;
> +	LIST_HEAD(link_chain);
> +
> +	if (!chan)
> +		return NULL;
> +
> +	if (!len)
> +		return NULL;
> +
> +	sh_chan = to_sh_chan(chan);
> +
> +	do {
> +		/* Allocate the link descriptor from DMA pool */
> +		new = sh_dmae_alloc_descriptor(sh_chan);
> +		if (!new) {
> +			dev_err(sh_chan->dev,
> +					"No free memory for link descriptor\n");
> +			return NULL;
> +		}
> +
> +		copy_size = min(len, (size_t)SH_DMA_TCR_MAX);
> +
> +		new->hw.sar = dma_src;
> +		new->hw.dar = dma_dest;
> +		new->hw.tcr = (copy_size >> calc_xmit_shift(sh_chan));
> +		if (!first)
> +			first = new;
> +
> +		new->mark = DESC_NCOMP;
> +		async_tx_ack(&new->async_tx);
> +
> +		prev = new;
> +		len -= copy_size;
> +		dma_src += copy_size;
> +		dma_dest += copy_size;
> +		cnt++;
> +		/* Insert the link descriptor to the LD ring */
> +		list_add_tail(&new->node, &first->async_tx.tx_list);
> +	} while (len);
> +
> +	new->async_tx.flags = flags; /* client is in control of this ack */
> +	new->async_tx.cookie = -EBUSY;
> +
> +	return first ? &first->async_tx : NULL;
> +}
> +
> +
> +
> +/*
> + * sh_chan_ld_cleanup - Clean up link descriptors
> + *
> + * This function clean up the ld_queue of DMA channel.
> + */
> +static void sh_dmae_chan_ld_cleanup(struct sh_dmae_chan *sh_chan)
> +{
> +	struct sh_desc *desc, *_desc;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&sh_chan->desc_lock, flags);
> +	list_for_each_entry_safe(desc, _desc, &sh_chan->ld_queue, node) {
> +		dma_async_tx_callback callback;
> +		void *callback_param;
> +
> +		/* non send data */
> +		if (desc->mark = DESC_NCOMP)
> +			break;
> +
> +		/* send data sesc */
> +		callback = desc->async_tx.callback;
> +		callback_param = desc->async_tx.callback_param;
> +
> +		/* Remove from ld_queue list */
> +		list_del(&desc->node);
> +
> +		dev_dbg(sh_chan->dev, "link descriptor %p will be recycle.\n",
> +				desc);
> +		kfree(desc);
> +		/* Run the link descriptor callback function */
> +		if (callback) {
> +			spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
> +			dev_dbg(sh_chan->dev, "link descriptor %p callback\n",
> +					desc);
> +			callback(callback_param);
> +			spin_lock_irqsave(&sh_chan->desc_lock, flags);
> +		}
> +	}
> +	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
> +}
> +
> +static void sh_chan_xfer_ld_queue(struct sh_dmae_chan *sh_chan)
> +{
> +	struct list_head *ld_node;
> +	unsigned long flags;
> +	struct sh_dmae_regs hw;
> +
> +	if (dmae_is_idle(sh_chan))
> +		return;
> +
> +	dmae_halt(sh_chan);
> +	spin_lock_irqsave(&sh_chan->desc_lock, flags);
> +
> +	/* Find the first un-transfer desciptor */
> +	for (ld_node = sh_chan->ld_queue.next;
> +		(ld_node != &sh_chan->ld_queue)
> +			&& (to_sh_desc(ld_node)->mark = DESC_COMP);
> +		ld_node = ld_node->next)
> +		cpu_relax();
> +
> +	if (ld_node != &sh_chan->ld_queue) {
> +		/* Get the ld start address from ld_queue */
> +		hw = to_sh_desc(ld_node)->hw;
> +		dmae_set_reg(sh_chan, hw);
> +		dmae_start(sh_chan);
> +	}
> +	spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
> +}
> +
> +static void sh_dmae_memcpy_issue_pending(struct dma_chan *chan)
> +{
> +	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
> +
> +	sh_chan_xfer_ld_queue(sh_chan);
> +}
> +
> +static enum dma_status sh_dmae_is_complete(struct dma_chan *chan,
> +					dma_cookie_t cookie,
> +					dma_cookie_t *done,
> +					dma_cookie_t *used)
> +{
> +	struct sh_dmae_chan *sh_chan = to_sh_chan(chan);
> +	dma_cookie_t last_used;
> +	dma_cookie_t last_complete;
> +
> +	sh_dmae_chan_ld_cleanup(sh_chan);
> +
> +	last_used = chan->cookie;
> +	last_complete = sh_chan->completed_cookie;
> +	if (last_complete = -EBUSY)
> +		last_complete = last_used;
> +
> +	if (done)
> +		*done = last_complete;
> +
> +	if (used)
> +		*used = last_used;
> +
> +	return dma_async_is_complete(cookie, last_complete, last_used);
> +}
> +
> +static irqreturn_t sh_dmae_interrupt(int irq, void *data)
> +{
> +	irqreturn_t ret = IRQ_NONE;
> +	struct sh_dmae_chan *sh_chan = (struct sh_dmae_chan *)data;
> +	u32 chcr = sh_dmae_readl(sh_chan, CHCR);
> +
> +	if (chcr & CHCR_TE) {
> +		unsigned long flags;
> +		struct sh_desc *desc, *_desc, *cur_desc = NULL;
> +		u32 sar_buf = sh_dmae_readl(sh_chan, SAR);
> +
> +		spin_lock_irqsave(&sh_chan->desc_lock, flags);
> +		list_for_each_entry_safe(desc, _desc,
> +						&sh_chan->ld_queue, node) {
> +			if ((desc->hw.sar + desc->hw.tcr) = sar_buf) {
> +				cur_desc = desc;
> +				break;
> +			}
> +		}
> +		spin_unlock_irqrestore(&sh_chan->desc_lock, flags);
> +
> +		if (cur_desc) {
> +			switch (cur_desc->async_tx.cookie) {
> +			case 0: /* other desc data */
> +				break;
> +			case -EBUSY: /* last desc */
> +				sh_chan->completed_cookie > +					cur_desc->async_tx.cookie;
> +				break;
> +			default: /* first desc ( 0 < )*/
> +				sh_chan->completed_cookie > +					cur_desc->async_tx.cookie - 1;
> +				break;
> +			}
> +			cur_desc->mark = DESC_COMP;
> +		}
> +		/* Next desc */
> +		sh_chan_xfer_ld_queue(sh_chan);
> +		ret = IRQ_HANDLED;
> +	}
> +	tasklet_schedule(&sh_chan->tasklet);
> +
> +	return ret;
> +}
> +
> +#if defined(CONFIG_CPU_SH4)
> +static irqreturn_t sh_dmae_err(int irq, void *data)
> +{
> +	int err = 0;
> +	struct sh_dmae_device *shdev = (struct sh_dmae_device *)data;
> +
> +	/* IRQ Multi */
> +	if (shdev->pdata.mode & SHDMA_MIX_IRQ) {
> +		int cnt = 0;
> +		switch (irq) {
> +#if defined(DMTE6_IRQ) && defined(DMAE1_IRQ)
> +		case DMTE6_IRQ:
> +			cnt++;
> +#endif
> +		case DMTE0_IRQ:
> +			if (dmaor_read_reg(cnt) & (DMAOR_NMIF | DMAOR_AE)) {
> +				disable_irq(irq);
> +				return IRQ_HANDLED;
> +			}
> +		default:
> +			return IRQ_NONE;
> +		}
> +	} else {
> +		/* reset dma controller */
> +		err = sh_dmae_rst(0);
> +		if (err)
> +			return err;
> +		if (shdev->pdata.mode & SHDMA_DMAOR1) {
> +			err = sh_dmae_rst(1);
> +			if (err)
> +				return err;
> +		}
> +		disable_irq(irq);
> +		return IRQ_HANDLED;
> +	}
> +}
> +#endif
> +
> +static void dmae_do_tasklet(unsigned long data)
> +{
> +	struct sh_dmae_chan *sh_chan = (struct sh_dmae_chan *)data;
> +	sh_dmae_chan_ld_cleanup(sh_chan);
> +}
> +
> +static unsigned int get_dmae_irq(unsigned int id)
> +{
> +	unsigned int irq = 0;
> +	if (id < ARRAY_SIZE(dmte_irq_map))
> +		irq = dmte_irq_map[id];
> +	return irq;
> +}
> +
> +static int __devinit sh_dmae_chan_probe(struct sh_dmae_device *shdev, int id)
> +{
> +	int err;
> +	unsigned int irq = get_dmae_irq(id);
> +	unsigned long irqflags = IRQF_DISABLED;
> +	struct sh_dmae_chan *new_sh_chan;
> +
> +	/* alloc channel */
> +	new_sh_chan = kzalloc(sizeof(struct sh_dmae_chan), GFP_KERNEL);
> +	if (!new_sh_chan) {
> +		dev_err(shdev->common.dev, "No free memory for allocating "
> +				"dma channels!\n");
> +		return -ENOMEM;
> +	}
> +
> +	new_sh_chan->dev = shdev->common.dev;
> +	shdev->chan[id] = new_sh_chan;
> +	new_sh_chan->id = id;
> +
> +	/* Init DMA tasklet */
> +	tasklet_init(&new_sh_chan->tasklet, dmae_do_tasklet,
> +			(unsigned long)new_sh_chan);
> +
> +	/* Init the channel */
> +	dmae_init(new_sh_chan);
> +
> +	spin_lock_init(&new_sh_chan->desc_lock);
> +
> +	/* Init descripter manage list */
> +	INIT_LIST_HEAD(&new_sh_chan->ld_queue);
> +
> +	/* copy struct dma_device */
> +	new_sh_chan->common.device = &shdev->common;
> +
> +	/* Add the channel to DMA device channel list */
> +	list_add_tail(&new_sh_chan->common.device_node,
> +			&shdev->common.channels);
> +	shdev->common.chancnt++;
> +
> +	if (shdev->pdata.mode & SHDMA_MIX_IRQ) {
> +		irqflags = IRQF_SHARED;
> +#if defined(DMTE6_IRQ)
> +		if (irq >= DMTE6_IRQ)
> +			irq = DMTE6_IRQ;
> +		else
> +#endif
> +			irq = DMTE0_IRQ;
> +	}
> +
> +	snprintf(new_sh_chan->dev_id, sizeof(new_sh_chan->dev_id),
> +			"sh-dmae%d", new_sh_chan->id);
> +
> +	/* set up channel irq */
> +	err = request_irq(irq, &sh_dmae_interrupt,
> +		irqflags, new_sh_chan->dev_id, new_sh_chan);
> +	if (err) {
> +		dev_err(shdev->common.dev, "DMA channel %d request_irq error "
> +			"with return %d\n", id, err);
> +		goto err_no_irq;
> +	}
> +
> +	/* CHCR register control function */
> +	new_sh_chan->set_chcr = dmae_set_chcr;
> +	/* DMARS register control function */
> +	new_sh_chan->set_dmars = dmae_set_dmars;
> +
> +	return 0;
> +
> +err_no_irq:
> +	/* remove from dmaengine device node */
> +	list_del(&new_sh_chan->common.device_node);
> +	kfree(new_sh_chan);
> +	return err;
> +}
> +
> +static void sh_dmae_chan_remove(struct sh_dmae_device *shdev)
> +{
> +	int i;
> +
> +	for (i = shdev->common.chancnt - 1 ; i >= 0 ; i--) {
> +		if (shdev->chan[i]) {
> +			struct sh_dmae_chan *shchan = shdev->chan[i];
> +			if (!(shdev->pdata.mode & SHDMA_MIX_IRQ))
> +				free_irq(dmte_irq_map[i], shchan);
> +
> +			list_del(&shchan->common.device_node);
> +			kfree(shchan);
> +			shdev->chan[i] = NULL;
> +		}
> +	}
> +	shdev->common.chancnt = 0;
> +}
> +
> +static int __init sh_dmae_probe(struct platform_device *pdev)
> +{
> +	int err = 0, cnt, ecnt;
> +	unsigned long irqflags = IRQF_DISABLED;
> +#if defined(CONFIG_CPU_SH4)
> +	int eirq[] = { DMAE0_IRQ,
> +#if defined(DMAE1_IRQ)
> +			DMAE1_IRQ
> +#endif
> +		};
> +#endif
> +	struct sh_dmae_device *shdev;
> +
> +	shdev = kzalloc(sizeof(struct sh_dmae_device), GFP_KERNEL);
> +	if (!shdev) {
> +		dev_err(&pdev->dev, "No enough memory\n");
> +		err = -ENOMEM;
> +		goto shdev_err;
> +	}
> +
> +	/* get platform data */
> +	if (!pdev->dev.platform_data)
> +		goto shdev_err;
> +
> +	/* platform data */
> +	memcpy(&shdev->pdata, pdev->dev.platform_data,
> +			sizeof(struct sh_dmae_pdata));
> +
> +	/* reset dma controller */
> +	err = sh_dmae_rst(0);
> +	if (err)
> +		goto rst_err;
> +
> +	/* SH7780/85/23 has DMAOR1 */
> +	if (shdev->pdata.mode & SHDMA_DMAOR1) {
> +		err = sh_dmae_rst(1);
> +		if (err)
> +			goto rst_err;
> +	}
> +
> +	INIT_LIST_HEAD(&shdev->common.channels);
> +
> +	dma_cap_set(DMA_MEMCPY, shdev->common.cap_mask);
> +	shdev->common.device_alloc_chan_resources
> +		= sh_dmae_alloc_chan_resources;
> +	shdev->common.device_free_chan_resources = sh_dmae_free_chan_resources;
> +	shdev->common.device_prep_dma_memcpy = sh_dmae_prep_memcpy;
> +	shdev->common.device_is_tx_complete = sh_dmae_is_complete;
> +	shdev->common.device_issue_pending = sh_dmae_memcpy_issue_pending;
> +	shdev->common.dev = &pdev->dev;
> +
> +#if defined(CONFIG_CPU_SH4)
> +	/* Non Mix IRQ mode SH7722/SH7730 etc... */
> +	if (shdev->pdata.mode & SHDMA_MIX_IRQ) {
> +		irqflags = IRQF_SHARED;
> +		eirq[0] = DMTE0_IRQ;
> +#if defined(DMTE6_IRQ) && defined(DMAE1_IRQ)
> +		eirq[1] = DMTE6_IRQ;
> +#endif
> +	}
> +
> +	for (ecnt = 0 ; ecnt < ARRAY_SIZE(eirq); ecnt++) {
> +		err = request_irq(eirq[ecnt], sh_dmae_err,
> +			irqflags, "DMAC Address Error", shdev);
> +		if (err) {
> +			dev_err(&pdev->dev, "DMA device request_irq"
> +				"erro (irq %d) with return %d\n",
> +				eirq[ecnt], err);
> +			goto eirq_err;
> +		}
> +	}
> +#endif /* CONFIG_CPU_SH4 */
> +
> +	/* Create DMA Channel */
> +	for (cnt = 0 ; cnt < MAX_DMA_CHANNELS ; cnt++) {
> +		err = sh_dmae_chan_probe(shdev, cnt);
> +		if (err)
> +			goto chan_probe_err;
> +	}
> +
> +	platform_set_drvdata(pdev, shdev);
> +	dma_async_device_register(&shdev->common);
> +
> +	return err;
> +
> +chan_probe_err:
> +	sh_dmae_chan_remove(shdev);
> +
> +eirq_err:
> +	for (ecnt-- ; ecnt >= 0; ecnt--)
> +		free_irq(eirq[ecnt], shdev);
> +
> +rst_err:
> +	kfree(shdev);
> +
> +shdev_err:
> +	return err;
> +}
> +
> +static int __exit sh_dmae_remove(struct platform_device *pdev)
> +{
> +	struct sh_dmae_device *shdev = platform_get_drvdata(pdev);
> +
> +	dma_async_device_unregister(&shdev->common);
> +
> +	if (shdev->pdata.mode & SHDMA_MIX_IRQ) {
> +		free_irq(DMTE0_IRQ, shdev);
> +#if defined(DMTE6_IRQ)
> +		free_irq(DMTE6_IRQ, shdev);
> +#endif
> +	}
> +
> +	/* channel data remove */
> +	sh_dmae_chan_remove(shdev);
> +
> +	if (!(shdev->pdata.mode & SHDMA_MIX_IRQ)) {
> +		free_irq(DMAE0_IRQ, shdev);
> +#if defined(DMAE1_IRQ)
> +		free_irq(DMAE1_IRQ, shdev);
> +#endif
> +	}
> +	kfree(shdev);
> +
> +	return 0;
> +}
> +
> +static void sh_dmae_shutdown(struct platform_device *pdev)
> +{
> +	struct sh_dmae_device *shdev = platform_get_drvdata(pdev);
> +	sh_dmae_ctl_stop(0);
> +	if (shdev->pdata.mode & SHDMA_DMAOR1)
> +		sh_dmae_ctl_stop(1);
> +}
> +
> +static struct platform_driver sh_dmae_driver = {
> +	.remove		= __exit_p(sh_dmae_remove),
> +	.shutdown	= sh_dmae_shutdown,
> +	.driver = {
> +		.name	= "sh-dma-engine",
> +	},
> +};
> +
> +static int __init sh_dmae_init(void)
> +{
> +	return platform_driver_probe(&sh_dmae_driver, sh_dmae_probe);
> +}
> +module_init(sh_dmae_init);
> +
> +static void __exit sh_dmae_exit(void)
> +{
> +	platform_driver_unregister(&sh_dmae_driver);
> +}
> +module_exit(sh_dmae_exit);
> +
> +MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>");
> +MODULE_DESCRIPTION("Renesas SH DMA Engine driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/dma/shdma.h b/drivers/dma/shdma.h
> new file mode 100644
> index 0000000..ebb4a9f
> --- /dev/null
> +++ b/drivers/dma/shdma.h
> @@ -0,0 +1,64 @@
> +/*
> + * Renesas SuperH DMA Engine support
> + *
> + * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
> + * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
> + *
> + * This 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.
> + *
> + */
> +#ifndef __DMA_SHDMA_H
> +#define __DMA_SHDMA_H
> +
> +#include <linux/device.h>
> +#include <linux/dmapool.h>
> +#include <linux/dmaengine.h>
> +
> +#define SH_DMA_TCR_MAX 0x00FFFFFF	/* 16MB */
> +
> +struct sh_dmae_regs {
> +	u32 sar; /* SAR / source address */
> +	u32 dar; /* DAR / destination address */
> +	u32 tcr; /* TCR / transfer count */
> +};
> +
> +struct sh_desc {
> +	struct sh_dmae_regs hw;
> +	struct list_head node;
> +	struct dma_async_tx_descriptor async_tx;
> +	struct list_head *ld;
> +	int mark;
> +};
> +
> +struct sh_dmae_chan {
> +	dma_cookie_t completed_cookie;	/* The maximum cookie completed */
> +	spinlock_t desc_lock;			/* Descriptor operation lock */
> +	struct list_head ld_queue;		/* Link descriptors queue */
> +	struct dma_chan common;			/* DMA common channel */
> +	struct device *dev;				/* Channel device */
> +	struct resource reg;			/* Resource for register */
> +	struct tasklet_struct tasklet;
> +	int id;	/* Raw id of this channel */
> +	char dev_id[16];	/* unique name per DMAC of channel */
> +
> +	/* Set chcr */
> +	int (*set_chcr)(struct sh_dmae_chan *sh_chan, u32 regs);
> +	/* Set DMA resource */
> +	int (*set_dmars)(struct sh_dmae_chan *sh_chan, u16 res);
> +};
> +
> +struct sh_dmae_device {
> +	struct resource reg;	/* Resource for register */
> +	struct dma_device common;
> +	struct sh_dmae_chan *chan[MAX_DMA_CHANNELS];
> +	struct sh_dmae_pdata pdata;
> +};
> +
> +#define to_sh_chan(chan) container_of(chan, struct sh_dmae_chan, common)
> +#define to_sh_desc(lh) container_of(lh, struct sh_desc, node)
> +#define tx_to_sh_desc(tx) container_of(tx, struct sh_desc, async_tx)
> +
> +#endif	/* __DMA_SHDMA_H */
> -- 
> 1.6.2.1
> 
> --
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RE: [PATCH v3] dmaengine: sh: Add Support SuperH DMA Engine driver

[Sosnowski, Maciej]

iwamatsu.nobuhiro@renesas.com wrote:
> This supported all DMA channels, and it was tested in SH7722,
> SH7780 and SH7763.
> This can not use with SH DMA API.
> 
> Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
> Reviewed-by: Matt Fleming <matt@console-pimps.org>
> ---
> 
>  V3: Reflect Maciej's comments.
> 
>  arch/sh/drivers/dma/Kconfig  |   12 +-
>  arch/sh/drivers/dma/Makefile |    3 +-
>  arch/sh/include/asm/dma-sh.h |   13 +
>  drivers/dma/Kconfig          |    8 +
>  drivers/dma/Makefile         |    2 +
>  drivers/dma/shdma.c          |  756  ++++++++++++++++++++++++++++++++++++++++++
>  drivers/dma/shdma.h        |   64 ++++
>  7 files changed, 853 insertions(+), 5 deletions(-)
>  create mode 100644 drivers/dma/shdma.c
>  create mode 100644 drivers/dma/shdma.h
> 

Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>

Re: [PATCH v3] dmaengine: sh: Add Support SuperH DMA Engine driver

[Dan Williams]

Paul Mundt wrote:
> On Wed, Mar 25, 2009 at 03:55:20PM +0900, Nobuhiro Iwamatsu wrote:
>> This supported all DMA channels, and it was tested in SH7722,
>> SH7780 and SH7763.
>> This can not use with SH DMA API.
>>
>> Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
>> Reviewed-by: Matt Fleming <matt@console-pimps.org>
> 
> I don't know why you dropped Dan from the CC, but you need his Acked-by
> or Reviewed-by before this can be merged.

Thanks Paul.

This version still has the problem of up leveling the descriptor lock to 
  spin_lock_irqsave from spin_lock_bh.  This poses a problem for 
completion callback support where callbacks assume that interrupts are 
enabled, like a timer callback.  I have also spotted a new problem below:

> 
>> ---
>>
>>  V3: Reflect Maciej's comments.
>>
>>  arch/sh/drivers/dma/Kconfig  |   12 +-
>>  arch/sh/drivers/dma/Makefile |    3 +-
>>  arch/sh/include/asm/dma-sh.h |   13 +
>>  drivers/dma/Kconfig          |    8 +
>>  drivers/dma/Makefile         |    2 +
>>  drivers/dma/shdma.c          |  756 ++++++++++++++++++++++++++++++++++++++++++
>>  drivers/dma/shdma.h          |   64 ++++
>>  7 files changed, 853 insertions(+), 5 deletions(-)
>>  create mode 100644 drivers/dma/shdma.c
>>  create mode 100644 drivers/dma/shdma.h
[..]
>> +static struct sh_desc *sh_dmae_alloc_descriptor(struct sh_dmae_chan *sh_chan)
>> +{
>> +     struct sh_desc *desc_sw;
>> +     desc_sw = kzalloc(sizeof(struct sh_desc), GFP_KERNEL);
>> +     if (desc_sw) {
>> +             dma_async_tx_descriptor_init(&desc_sw->async_tx,
>> +                                             &sh_chan->common);
>> +             desc_sw->async_tx.tx_submit = sh_dmae_tx_submit;
>> +             INIT_LIST_HEAD(&desc_sw->async_tx.tx_list);
>> +     }
>> +
>> +     return desc_sw;
>> +}
>> +
>> +static int sh_dmae_alloc_chan_resources(struct dma_chan *chan)
>> +{
>> +     return 1;
>> +}

The point of this routine is to preallocate descriptors because...

>> +
>> +/*
>> + * sh_dma_free_chan_resources - Free all resources of the channel.
>> + */
[..]
>> +
>> +static struct dma_async_tx_descriptor *sh_dmae_prep_memcpy(
>> +     struct dma_chan *chan, dma_addr_t dma_dest, dma_addr_t dma_src,
>> +     size_t len, unsigned long flags)
>> +{
>> +     struct sh_dmae_chan *sh_chan;
>> +     struct sh_desc *first = NULL, *prev = NULL, *new;
>> +     size_t copy_size;
>> +     int cnt = 0;
>> +     LIST_HEAD(link_chain);
>> +
>> +     if (!chan)
>> +             return NULL;
>> +
>> +     if (!len)
>> +             return NULL;
>> +
>> +     sh_chan = to_sh_chan(chan);
>> +
>> +     do {
>> +             /* Allocate the link descriptor from DMA pool */
>> +             new = sh_dmae_alloc_descriptor(sh_chan);

...we may not be able to do a GFP_KERNEL allocation here.

>> +             if (!new) {
>> +                     dev_err(sh_chan->dev,
>> +                                     "No free memory for link descriptor\n");
>> +                     return NULL;
>> +             }

--
Dan

Re: [PATCH v3] dmaengine: sh: Add Support SuperH DMA Engine driver

[Nobuhiro Iwamatsu]

Paul Mundt wrote:
> On Wed, Mar 25, 2009 at 03:55:20PM +0900, Nobuhiro Iwamatsu wrote:
>> This supported all DMA channels, and it was tested in SH7722,
>> SH7780 and SH7763.
>> This can not use with SH DMA API.
>>
>> Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
>> Reviewed-by: Matt Fleming <matt@console-pimps.org>
> 
> I don't know why you dropped Dan from the CC, but you need his Acked-by
> or Reviewed-by before this can be merged.
> 
I'm sorry. I forgot add Dan to CC.

Best regards,
  Nobuhiro

Re: [PATCH v3] dmaengine: sh: Add Support SuperH DMA Engine driver

[Nobuhiro Iwamatsu]

Hi, Dan.

Thank you for your commnets.

Dan Williams wrote:
> Paul Mundt wrote:
>> On Wed, Mar 25, 2009 at 03:55:20PM +0900, Nobuhiro Iwamatsu wrote:
>>> This supported all DMA channels, and it was tested in SH7722,
>>> SH7780 and SH7763.
>>> This can not use with SH DMA API.
>>>
>>> Signed-off-by: Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
>>> Reviewed-by: Matt Fleming <matt@console-pimps.org>
>>
>> I don't know why you dropped Dan from the CC, but you need his Acked-by
>> or Reviewed-by before this can be merged.
> 
> Thanks Paul.
> 
> This version still has the problem of up leveling the descriptor lock to 
>  spin_lock_irqsave from spin_lock_bh.  This poses a problem for 
> completion callback support where callbacks assume that interrupts are 
> enabled, like a timer callback.  I have also spotted a new problem below:
> 

I understood. I fix your undication part.

Best regards,
  Nobuhiro