Date:	Thu, 30 May 2013 18:25:02 +0200
From:	Lars-Peter Clausen <lars@...afoo.de>
To:	Ralf Baechle <ralf@...ux-mips.org>,
	Vinod Koul <vinod.koul@...el.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>
Cc:	Maarten ter Huurne <maarten@...ewalker.org>,
	linux-mips@...ux-mips.org, linux-kernel@...r.kernel.org,
	alsa-devel@...a-project.org, Lars-Peter Clausen <lars@...afoo.de>
Subject: [PATCH v2 3/6] dma: Add a jz4740 dmaengine driver

This patch adds dmaengine support for the JZ4740 DMA controller. For now the
driver will be a wrapper around the custom JZ4740 DMA API. Once all users of the
custom JZ4740 DMA API have been converted to the dmaengine API the custom API
will be removed and direct hardware access will be added to the dmaengine
driver.

Signed-off-by: Lars-Peter Clausen <lars@...afoo.de>
---
Changes since v1:
	* Only save the fifo addr instead of the full slave config
	* #define JZ4740_DMA_NR_CHANS 6
	* Return ENOSYS for unsuppored commands in the device_control() callback
---
 drivers/dma/Kconfig      |   6 +
 drivers/dma/Makefile     |   1 +
 drivers/dma/dma-jz4740.c | 433 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 440 insertions(+)
 create mode 100644 drivers/dma/dma-jz4740.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index e992489..b3e8952 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -312,6 +312,12 @@ config MMP_PDMA
 	help
 	  Support the MMP PDMA engine for PXA and MMP platfrom.
 
+config DMA_JZ4740
+	tristate "JZ4740 DMA support"
+	depends on MACH_JZ4740
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+
 config DMA_ENGINE
 	bool
 
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index a2b0df5..6127a61 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -38,3 +38,4 @@ obj-$(CONFIG_DMA_SA11X0) += sa11x0-dma.o
 obj-$(CONFIG_MMP_TDMA) += mmp_tdma.o
 obj-$(CONFIG_DMA_OMAP) += omap-dma.o
 obj-$(CONFIG_MMP_PDMA) += mmp_pdma.o
+obj-$(CONFIG_DMA_JZ4740) += dma-jz4740.o
diff --git a/drivers/dma/dma-jz4740.c b/drivers/dma/dma-jz4740.c
new file mode 100644
index 0000000..3d42434
--- /dev/null
+++ b/drivers/dma/dma-jz4740.c
@@ -0,0 +1,433 @@
+/*
+ *  Copyright (C) 2013, Lars-Peter Clausen <lars@...afoo.de>
+ *  JZ4740 DMAC support
+ *
+ *  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.
+ *
+ *  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.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <asm/mach-jz4740/dma.h>
+
+#include "virt-dma.h"
+
+#define JZ_DMA_NR_CHANS 6
+
+struct jz4740_dma_sg {
+	dma_addr_t addr;
+	unsigned int len;
+};
+
+struct jz4740_dma_desc {
+	struct virt_dma_desc vdesc;
+
+	enum dma_transfer_direction direction;
+	bool cyclic;
+
+	unsigned int num_sgs;
+	struct jz4740_dma_sg sg[];
+};
+
+struct jz4740_dmaengine_chan {
+	struct virt_dma_chan vchan;
+	struct jz4740_dma_chan *jz_chan;
+
+	dma_addr_t fifo_addr;
+
+	struct jz4740_dma_desc *desc;
+	unsigned int next_sg;
+};
+
+struct jz4740_dma_dev {
+	struct dma_device ddev;
+
+	struct jz4740_dmaengine_chan chan[JZ_DMA_NR_CHANS];
+};
+
+static struct jz4740_dmaengine_chan *to_jz4740_dma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct jz4740_dmaengine_chan, vchan.chan);
+}
+
+static struct jz4740_dma_desc *to_jz4740_dma_desc(struct virt_dma_desc *vdesc)
+{
+	return container_of(vdesc, struct jz4740_dma_desc, vdesc);
+}
+
+static struct jz4740_dma_desc *jz4740_dma_alloc_desc(unsigned int num_sgs)
+{
+	return kzalloc(sizeof(struct jz4740_dma_desc) +
+		sizeof(struct jz4740_dma_sg) * num_sgs, GFP_ATOMIC);
+}
+
+static enum jz4740_dma_width jz4740_dma_width(enum dma_slave_buswidth width)
+{
+	switch (width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		return JZ4740_DMA_WIDTH_8BIT;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		return JZ4740_DMA_WIDTH_16BIT;
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		return JZ4740_DMA_WIDTH_32BIT;
+	default:
+		return JZ4740_DMA_WIDTH_32BIT;
+	}
+}
+
+static enum jz4740_dma_transfer_size jz4740_dma_maxburst(u32 maxburst)
+{
+	if (maxburst <= 1)
+		return JZ4740_DMA_TRANSFER_SIZE_1BYTE;
+	else if (maxburst <= 3)
+		return JZ4740_DMA_TRANSFER_SIZE_2BYTE;
+	else if (maxburst <= 15)
+		return JZ4740_DMA_TRANSFER_SIZE_4BYTE;
+	else if (maxburst <= 31)
+		return JZ4740_DMA_TRANSFER_SIZE_16BYTE;
+
+	return JZ4740_DMA_TRANSFER_SIZE_32BYTE;
+}
+
+static int jz4740_dma_slave_config(struct dma_chan *c,
+	const struct dma_slave_config *config)
+{
+	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+	struct jz4740_dma_config jzcfg;
+
+	switch (config->direction) {
+	case DMA_MEM_TO_DEV:
+		jzcfg.flags = JZ4740_DMA_SRC_AUTOINC;
+		jzcfg.transfer_size = jz4740_dma_maxburst(config->dst_maxburst);
+		chan->fifo_addr = config->dst_addr;
+		break;
+	case DMA_DEV_TO_MEM:
+		jzcfg.flags = JZ4740_DMA_DST_AUTOINC;
+		jzcfg.transfer_size = jz4740_dma_maxburst(config->src_maxburst);
+		chan->fifo_addr = config->src_addr;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+
+	jzcfg.src_width = jz4740_dma_width(config->src_addr_width);
+	jzcfg.dst_width = jz4740_dma_width(config->dst_addr_width);
+	jzcfg.mode = JZ4740_DMA_MODE_SINGLE;
+	jzcfg.request_type = config->slave_id;
+
+	jz4740_dma_configure(chan->jz_chan, &jzcfg);
+
+	return 0;
+}
+
+static int jz4740_dma_terminate_all(struct dma_chan *c)
+{
+	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	jz4740_dma_disable(chan->jz_chan);
+	chan->desc = NULL;
+	vchan_get_all_descriptors(&chan->vchan, &head);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	vchan_dma_desc_free_list(&chan->vchan, &head);
+
+	return 0;
+}
+
+static int jz4740_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+	unsigned long arg)
+{
+	struct dma_slave_config *config = (struct dma_slave_config *)arg;
+
+	switch (cmd) {
+	case DMA_SLAVE_CONFIG:
+		return jz4740_dma_slave_config(chan, config);
+	case DMA_TERMINATE_ALL:
+		return jz4740_dma_terminate_all(chan);
+	default:
+		return -ENOSYS;
+	}
+}
+
+static int jz4740_dma_start_transfer(struct jz4740_dmaengine_chan *chan)
+{
+	dma_addr_t src_addr, dst_addr;
+	struct virt_dma_desc *vdesc;
+	struct jz4740_dma_sg *sg;
+
+	jz4740_dma_disable(chan->jz_chan);
+
+	if (!chan->desc) {
+		vdesc = vchan_next_desc(&chan->vchan);
+		if (!vdesc)
+			return 0;
+		chan->desc = to_jz4740_dma_desc(vdesc);
+		chan->next_sg = 0;
+	}
+
+	if (chan->next_sg == chan->desc->num_sgs)
+		chan->next_sg = 0;
+
+	sg = &chan->desc->sg[chan->next_sg];
+
+	if (chan->desc->direction == DMA_MEM_TO_DEV) {
+		src_addr = sg->addr;
+		dst_addr = chan->fifo_addr;
+	} else {
+		src_addr = chan->fifo_addr;
+		dst_addr = sg->addr;
+	}
+	jz4740_dma_set_src_addr(chan->jz_chan, src_addr);
+	jz4740_dma_set_dst_addr(chan->jz_chan, dst_addr);
+	jz4740_dma_set_transfer_count(chan->jz_chan, sg->len);
+
+	chan->next_sg++;
+
+	jz4740_dma_enable(chan->jz_chan);
+
+	return 0;
+}
+
+static void jz4740_dma_complete_cb(struct jz4740_dma_chan *jz_chan, int error,
+	void *devid)
+{
+	struct jz4740_dmaengine_chan *chan = devid;
+
+	spin_lock(&chan->vchan.lock);
+	if (chan->desc) {
+		if (chan->desc && chan->desc->cyclic) {
+			vchan_cyclic_callback(&chan->desc->vdesc);
+		} else {
+			if (chan->next_sg == chan->desc->num_sgs) {
+				chan->desc = NULL;
+				vchan_cookie_complete(&chan->desc->vdesc);
+			}
+		}
+	}
+	jz4740_dma_start_transfer(chan);
+	spin_unlock(&chan->vchan.lock);
+}
+
+static void jz4740_dma_issue_pending(struct dma_chan *c)
+{
+	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	if (vchan_issue_pending(&chan->vchan) && !chan->desc)
+		jz4740_dma_start_transfer(chan);
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static struct dma_async_tx_descriptor *jz4740_dma_prep_slave_sg(
+	struct dma_chan *c, struct scatterlist *sgl,
+	unsigned int sg_len, enum dma_transfer_direction direction,
+	unsigned long flags, void *context)
+{
+	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+	struct jz4740_dma_desc *desc;
+	struct scatterlist *sg;
+	unsigned int i;
+
+	desc = jz4740_dma_alloc_desc(sg_len);
+	if (!desc)
+		return NULL;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		desc->sg[i].addr = sg_dma_address(sg);
+		desc->sg[i].len = sg_dma_len(sg);
+	}
+
+	desc->num_sgs = sg_len;
+	desc->direction = direction;
+	desc->cyclic = false;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static struct dma_async_tx_descriptor *jz4740_dma_prep_dma_cyclic(
+	struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
+	size_t period_len, enum dma_transfer_direction direction,
+	unsigned long flags, void *context)
+{
+	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+	struct jz4740_dma_desc *desc;
+	unsigned int num_periods, i;
+
+	if (buf_len % period_len)
+		return NULL;
+
+	num_periods = buf_len / period_len;
+
+	desc = jz4740_dma_alloc_desc(num_periods);
+	if (!desc)
+		return NULL;
+
+	for (i = 0; i < num_periods; i++) {
+		desc->sg[i].addr = buf_addr;
+		desc->sg[i].len = period_len;
+		buf_addr += period_len;
+	}
+
+	desc->num_sgs = num_periods;
+	desc->direction = direction;
+	desc->cyclic = true;
+
+	return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static size_t jz4740_dma_desc_residue(struct jz4740_dmaengine_chan *chan,
+	struct jz4740_dma_desc *desc, unsigned int next_sg)
+{
+	size_t residue = 0;
+	unsigned int i;
+
+	residue = 0;
+
+	for (i = next_sg; i < desc->num_sgs; i++)
+		residue += desc->sg[i].len;
+
+	if (next_sg != 0)
+		residue += jz4740_dma_get_residue(chan->jz_chan);
+
+	return residue;
+}
+
+static enum dma_status jz4740_dma_tx_status(struct dma_chan *c,
+	dma_cookie_t cookie, struct dma_tx_state *state)
+{
+	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+	struct virt_dma_desc *vdesc;
+	enum dma_status status;
+	unsigned long flags;
+
+	status = dma_cookie_status(c, cookie, state);
+	if (status == DMA_SUCCESS || !state)
+		return status;
+
+	spin_lock_irqsave(&chan->vchan.lock, flags);
+	vdesc = vchan_find_desc(&chan->vchan, cookie);
+	if (cookie == chan->desc->vdesc.tx.cookie) {
+		state->residue = jz4740_dma_desc_residue(chan, chan->desc,
+				chan->next_sg);
+	} else if (vdesc) {
+		state->residue = jz4740_dma_desc_residue(chan,
+				to_jz4740_dma_desc(vdesc), 0);
+	} else {
+		state->residue = 0;
+	}
+	spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+	return status;
+}
+
+static int jz4740_dma_alloc_chan_resources(struct dma_chan *c)
+{
+	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+
+	chan->jz_chan = jz4740_dma_request(chan, NULL);
+	if (!chan->jz_chan)
+		return -EBUSY;
+
+	jz4740_dma_set_complete_cb(chan->jz_chan, jz4740_dma_complete_cb);
+
+	return 0;
+}
+
+static void jz4740_dma_free_chan_resources(struct dma_chan *c)
+{
+	struct jz4740_dmaengine_chan *chan = to_jz4740_dma_chan(c);
+
+	vchan_free_chan_resources(&chan->vchan);
+	jz4740_dma_free(chan->jz_chan);
+	chan->jz_chan = NULL;
+}
+
+static void jz4740_dma_desc_free(struct virt_dma_desc *vdesc)
+{
+	kfree(container_of(vdesc, struct jz4740_dma_desc, vdesc));
+}
+
+static int jz4740_dma_probe(struct platform_device *pdev)
+{
+	struct jz4740_dmaengine_chan *chan;
+	struct jz4740_dma_dev *dmadev;
+	struct dma_device *dd;
+	unsigned int i;
+	int ret;
+
+	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
+	if (!dmadev)
+		return -EINVAL;
+
+	dd = &dmadev->ddev;
+
+	dma_cap_set(DMA_SLAVE, dd->cap_mask);
+	dma_cap_set(DMA_CYCLIC, dd->cap_mask);
+	dd->device_alloc_chan_resources = jz4740_dma_alloc_chan_resources;
+	dd->device_free_chan_resources = jz4740_dma_free_chan_resources;
+	dd->device_tx_status = jz4740_dma_tx_status;
+	dd->device_issue_pending = jz4740_dma_issue_pending;
+	dd->device_prep_slave_sg = jz4740_dma_prep_slave_sg;
+	dd->device_prep_dma_cyclic = jz4740_dma_prep_dma_cyclic;
+	dd->device_control = jz4740_dma_control;
+	dd->dev = &pdev->dev;
+	dd->chancnt = JZ_DMA_NR_CHANS;
+	INIT_LIST_HEAD(&dd->channels);
+
+	for (i = 0; i < dd->chancnt; i++) {
+		chan = &dmadev->chan[i];
+		chan->vchan.desc_free = jz4740_dma_desc_free;
+		vchan_init(&chan->vchan, dd);
+	}
+
+	ret = dma_async_device_register(dd);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, dmadev);
+
+	return 0;
+}
+
+static int jz4740_dma_remove(struct platform_device *pdev)
+{
+	struct jz4740_dma_dev *dmadev = platform_get_drvdata(pdev);
+
+	dma_async_device_unregister(&dmadev->ddev);
+
+	return 0;
+}
+
+static struct platform_driver jz4740_dma_driver = {
+	.probe = jz4740_dma_probe,
+	.remove = jz4740_dma_remove,
+	.driver = {
+		.name = "jz4740-dma",
+		.owner = THIS_MODULE,
+	},
+};
+module_platform_driver(jz4740_dma_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@...afoo.de>");
+MODULE_DESCRIPTION("JZ4740 DMA driver");
+MODULE_LICENSE("GPLv2");
-- 
1.8.2.1

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