dmaengine: add OMAP DMA engine driver

Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/dma/Kconfig

@@ -261,6 +261,12 @@ config DMA_SA11X0
 	  SA-1110 SoCs.  This DMA engine can only be used with on-chip
 	  devices.
 
+config DMA_OMAP
+	tristate "OMAP DMA support"
+	depends on ARCH_OMAP
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+
 config DMA_ENGINE
 	bool
 

drivers/dma/Makefile

@@ -29,3 +29,4 @@ obj-$(CONFIG_PCH_DMA) += pch_dma.o
 obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o
 obj-$(CONFIG_EP93XX_DMA) += ep93xx_dma.o
 obj-$(CONFIG_DMA_SA11X0) += sa11x0-dma.o
+obj-$(CONFIG_DMA_OMAP) += omap-dma.o

drivers/dma/omap-dma.c

@@ -0,0 +1,524 @@
+/*
+ * OMAP DMAengine support
+ *
+ * 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/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/omap-dma.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "virt-dma.h"
+#include <plat/dma.h>
+
+struct omap_dmadev {
+	struct dma_device ddev;
+	spinlock_t lock;
+	struct tasklet_struct task;
+	struct list_head pending;
+};
+
+struct omap_chan {
+	struct virt_dma_chan vc;
+	struct list_head node;
+
+	struct dma_slave_config	cfg;
+	unsigned dma_sig;
+
+	int dma_ch;
+	struct omap_desc *desc;
+	unsigned sgidx;
+};
+
+struct omap_sg {
+	dma_addr_t addr;
+	uint32_t en;		/* number of elements (24-bit) */
+	uint32_t fn;		/* number of frames (16-bit) */
+};
+
+struct omap_desc {
+	struct virt_dma_desc vd;
+	enum dma_transfer_direction dir;
+	dma_addr_t dev_addr;
+
+	uint8_t es;		/* OMAP_DMA_DATA_TYPE_xxx */
+	uint8_t sync_mode;	/* OMAP_DMA_SYNC_xxx */
+	uint8_t sync_type;	/* OMAP_DMA_xxx_SYNC* */
+	uint8_t periph_port;	/* Peripheral port */
+
+	unsigned sglen;
+	struct omap_sg sg[0];
+};
+
+static const unsigned es_bytes[] = {
+	[OMAP_DMA_DATA_TYPE_S8] = 1,
+	[OMAP_DMA_DATA_TYPE_S16] = 2,
+	[OMAP_DMA_DATA_TYPE_S32] = 4,
+};
+
+static inline struct omap_dmadev *to_omap_dma_dev(struct dma_device *d)
+{
+	return container_of(d, struct omap_dmadev, ddev);
+}
+
+static inline struct omap_chan *to_omap_dma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct omap_chan, vc.chan);
+}
+
+static inline struct omap_desc *to_omap_dma_desc(struct dma_async_tx_descriptor *t)
+{
+	return container_of(t, struct omap_desc, vd.tx);
+}
+
+static void omap_dma_desc_free(struct virt_dma_desc *vd)
+{
+	kfree(container_of(vd, struct omap_desc, vd));
+}
+
+static void omap_dma_start_sg(struct omap_chan *c, struct omap_desc *d,
+	unsigned idx)
+{
+	struct omap_sg *sg = d->sg + idx;
+
+	if (d->dir == DMA_DEV_TO_MEM)
+		omap_set_dma_dest_params(c->dma_ch, OMAP_DMA_PORT_EMIFF,
+			OMAP_DMA_AMODE_POST_INC, sg->addr, 0, 0);
+	else
+		omap_set_dma_src_params(c->dma_ch, OMAP_DMA_PORT_EMIFF,
+			OMAP_DMA_AMODE_POST_INC, sg->addr, 0, 0);
+
+	omap_set_dma_transfer_params(c->dma_ch, d->es, sg->en, sg->fn,
+		d->sync_mode, c->dma_sig, d->sync_type);
+
+	omap_start_dma(c->dma_ch);
+}
+
+static void omap_dma_start_desc(struct omap_chan *c)
+{
+	struct virt_dma_desc *vd = vchan_next_desc(&c->vc);
+	struct omap_desc *d;
+
+	if (!vd) {
+		c->desc = NULL;
+		return;
+	}
+
+	list_del(&vd->node);
+
+	c->desc = d = to_omap_dma_desc(&vd->tx);
+	c->sgidx = 0;
+
+	if (d->dir == DMA_DEV_TO_MEM)
+		omap_set_dma_src_params(c->dma_ch, d->periph_port,
+			OMAP_DMA_AMODE_CONSTANT, d->dev_addr, 0, 0);
+	else
+		omap_set_dma_dest_params(c->dma_ch, d->periph_port,
+			OMAP_DMA_AMODE_CONSTANT, d->dev_addr, 0, 0);
+
+	omap_dma_start_sg(c, d, 0);
+}
+
+static void omap_dma_callback(int ch, u16 status, void *data)
+{
+	struct omap_chan *c = data;
+	struct omap_desc *d;
+	unsigned long flags;
+
+	spin_lock_irqsave(&c->vc.lock, flags);
+	d = c->desc;
+	if (d) {
+		if (++c->sgidx < d->sglen) {
+			omap_dma_start_sg(c, d, c->sgidx);
+		} else {
+			omap_dma_start_desc(c);
+			vchan_cookie_complete(&d->vd);
+		}
+	}
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+}
+
+/*
+ * This callback schedules all pending channels.  We could be more
+ * clever here by postponing allocation of the real DMA channels to
+ * this point, and freeing them when our virtual channel becomes idle.
+ *
+ * We would then need to deal with 'all channels in-use'
+ */
+static void omap_dma_sched(unsigned long data)
+{
+	struct omap_dmadev *d = (struct omap_dmadev *)data;
+	LIST_HEAD(head);
+
+	spin_lock_irq(&d->lock);
+	list_splice_tail_init(&d->pending, &head);
+	spin_unlock_irq(&d->lock);
+
+	while (!list_empty(&head)) {
+		struct omap_chan *c = list_first_entry(&head,
+			struct omap_chan, node);
+
+		spin_lock_irq(&c->vc.lock);
+		list_del_init(&c->node);
+		omap_dma_start_desc(c);
+		spin_unlock_irq(&c->vc.lock);
+	}
+}
+
+static int omap_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct omap_chan *c = to_omap_dma_chan(chan);
+
+	dev_info(c->vc.chan.device->dev, "allocating channel for %u\n", c->dma_sig);
+
+	return omap_request_dma(c->dma_sig, "DMA engine",
+		omap_dma_callback, c, &c->dma_ch);
+}
+
+static void omap_dma_free_chan_resources(struct dma_chan *chan)
+{
+	struct omap_chan *c = to_omap_dma_chan(chan);
+
+	vchan_free_chan_resources(&c->vc);
+	omap_free_dma(c->dma_ch);
+
+	dev_info(c->vc.chan.device->dev, "freeing channel for %u\n", c->dma_sig);
+}
+
+static enum dma_status omap_dma_tx_status(struct dma_chan *chan,
+	dma_cookie_t cookie, struct dma_tx_state *txstate)
+{
+	/*
+	 * FIXME: do we need to return pending bytes?
+	 * We have no users of that info at the moment...
+	 */
+	return dma_cookie_status(chan, cookie, txstate);
+}
+
+static void omap_dma_issue_pending(struct dma_chan *chan)
+{
+	struct omap_chan *c = to_omap_dma_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&c->vc.lock, flags);
+	if (vchan_issue_pending(&c->vc) && !c->desc) {
+		struct omap_dmadev *d = to_omap_dma_dev(chan->device);
+		spin_lock(&d->lock);
+		if (list_empty(&c->node))
+			list_add_tail(&c->node, &d->pending);
+		spin_unlock(&d->lock);
+		tasklet_schedule(&d->task);
+	}
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+}
+
+static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
+	struct dma_chan *chan, struct scatterlist *sgl, unsigned sglen,
+	enum dma_transfer_direction dir, unsigned long tx_flags, void *context)
+{
+	struct omap_chan *c = to_omap_dma_chan(chan);
+	enum dma_slave_buswidth dev_width;
+	struct scatterlist *sgent;
+	struct omap_desc *d;
+	dma_addr_t dev_addr;
+	unsigned i, j = 0, es, en, frame_bytes, sync_type;
+	u32 burst;
+
+	if (dir == DMA_DEV_TO_MEM) {
+		dev_addr = c->cfg.src_addr;
+		dev_width = c->cfg.src_addr_width;
+		burst = c->cfg.src_maxburst;
+		sync_type = OMAP_DMA_SRC_SYNC;
+	} else if (dir == DMA_MEM_TO_DEV) {
+		dev_addr = c->cfg.dst_addr;
+		dev_width = c->cfg.dst_addr_width;
+		burst = c->cfg.dst_maxburst;
+		sync_type = OMAP_DMA_DST_SYNC;
+	} else {
+		dev_err(chan->device->dev, "%s: bad direction?\n", __func__);
+		return NULL;
+	}
+
+	/* Bus width translates to the element size (ES) */
+	switch (dev_width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		es = OMAP_DMA_DATA_TYPE_S8;
+		break;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		es = OMAP_DMA_DATA_TYPE_S16;
+		break;
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		es = OMAP_DMA_DATA_TYPE_S32;
+		break;
+	default: /* not reached */
+		return NULL;
+	}
+
+	/* Now allocate and setup the descriptor. */
+	d = kzalloc(sizeof(*d) + sglen * sizeof(d->sg[0]), GFP_ATOMIC);
+	if (!d)
+		return NULL;
+
+	d->dir = dir;
+	d->dev_addr = dev_addr;
+	d->es = es;
+	d->sync_mode = OMAP_DMA_SYNC_FRAME;
+	d->sync_type = sync_type;
+	d->periph_port = OMAP_DMA_PORT_TIPB;
+
+	/*
+	 * Build our scatterlist entries: each contains the address,
+	 * the number of elements (EN) in each frame, and the number of
+	 * frames (FN).  Number of bytes for this entry = ES * EN * FN.
+	 *
+	 * Burst size translates to number of elements with frame sync.
+	 * Note: DMA engine defines burst to be the number of dev-width
+	 * transfers.
+	 */
+	en = burst;
+	frame_bytes = es_bytes[es] * en;
+	for_each_sg(sgl, sgent, sglen, i) {
+		d->sg[j].addr = sg_dma_address(sgent);
+		d->sg[j].en = en;
+		d->sg[j].fn = sg_dma_len(sgent) / frame_bytes;
+		j++;
+	}
+
+	d->sglen = j;
+
+	return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
+}
+
+static int omap_dma_slave_config(struct omap_chan *c, struct dma_slave_config *cfg)
+{
+	if (cfg->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES ||
+	    cfg->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
+		return -EINVAL;
+
+	memcpy(&c->cfg, cfg, sizeof(c->cfg));
+
+	return 0;
+}
+
+static int omap_dma_terminate_all(struct omap_chan *c)
+{
+	struct omap_dmadev *d = to_omap_dma_dev(c->vc.chan.device);
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&c->vc.lock, flags);
+
+	/* Prevent this channel being scheduled */
+	spin_lock(&d->lock);
+	list_del_init(&c->node);
+	spin_unlock(&d->lock);
+
+	/*
+	 * Stop DMA activity: we assume the callback will not be called
+	 * after omap_stop_dma() returns (even if it does, it will see
+	 * c->desc is NULL and exit.)
+	 */
+	if (c->desc) {
+		c->desc = NULL;
+		omap_stop_dma(c->dma_ch);
+	}
+
+	vchan_get_all_descriptors(&c->vc, &head);
+	spin_unlock_irqrestore(&c->vc.lock, flags);
+	vchan_dma_desc_free_list(&c->vc, &head);
+
+	return 0;
+}
+
+static int omap_dma_pause(struct omap_chan *c)
+{
+	/* FIXME: not supported by platform private API */
+	return -EINVAL;
+}
+
+static int omap_dma_resume(struct omap_chan *c)
+{
+	/* FIXME: not supported by platform private API */
+	return -EINVAL;
+}
+
+static int omap_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+	unsigned long arg)
+{
+	struct omap_chan *c = to_omap_dma_chan(chan);
+	int ret;
+
+	switch (cmd) {
+	case DMA_SLAVE_CONFIG:
+		ret = omap_dma_slave_config(c, (struct dma_slave_config *)arg);
+		break;
+
+	case DMA_TERMINATE_ALL:
+		ret = omap_dma_terminate_all(c);
+		break;
+
+	case DMA_PAUSE:
+		ret = omap_dma_pause(c);
+		break;
+
+	case DMA_RESUME:
+		ret = omap_dma_resume(c);
+		break;
+
+	default:
+		ret = -ENXIO;
+		break;
+	}
+
+	return ret;
+}
+
+static int omap_dma_chan_init(struct omap_dmadev *od, int dma_sig)
+{
+	struct omap_chan *c;
+
+	c = kzalloc(sizeof(*c), GFP_KERNEL);
+	if (!c)
+		return -ENOMEM;
+
+	c->dma_sig = dma_sig;
+	c->vc.desc_free = omap_dma_desc_free;
+	vchan_init(&c->vc, &od->ddev);
+	INIT_LIST_HEAD(&c->node);
+
+	od->ddev.chancnt++;
+
+	return 0;
+}
+
+static void omap_dma_free(struct omap_dmadev *od)
+{
+	tasklet_kill(&od->task);
+	while (!list_empty(&od->ddev.channels)) {
+		struct omap_chan *c = list_first_entry(&od->ddev.channels,
+			struct omap_chan, vc.chan.device_node);
+
+		list_del(&c->vc.chan.device_node);
+		tasklet_kill(&c->vc.task);
+		kfree(c);
+	}
+	kfree(od);
+}
+
+static int omap_dma_probe(struct platform_device *pdev)
+{
+	struct omap_dmadev *od;
+	int rc, i;
+
+	od = kzalloc(sizeof(*od), GFP_KERNEL);
+	if (!od)
+		return -ENOMEM;
+
+	dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
+	od->ddev.device_alloc_chan_resources = omap_dma_alloc_chan_resources;
+	od->ddev.device_free_chan_resources = omap_dma_free_chan_resources;
+	od->ddev.device_tx_status = omap_dma_tx_status;
+	od->ddev.device_issue_pending = omap_dma_issue_pending;
+	od->ddev.device_prep_slave_sg = omap_dma_prep_slave_sg;
+	od->ddev.device_control = omap_dma_control;
+	od->ddev.dev = &pdev->dev;
+	INIT_LIST_HEAD(&od->ddev.channels);
+	INIT_LIST_HEAD(&od->pending);
+	spin_lock_init(&od->lock);
+
+	tasklet_init(&od->task, omap_dma_sched, (unsigned long)od);
+
+	for (i = 0; i < 127; i++) {
+		rc = omap_dma_chan_init(od, i);
+		if (rc) {
+			omap_dma_free(od);
+			return rc;
+		}
+	}
+
+	rc = dma_async_device_register(&od->ddev);
+	if (rc) {
+		pr_warn("OMAP-DMA: failed to register slave DMA engine device: %d\n",
+			rc);
+		omap_dma_free(od);
+	} else {
+		platform_set_drvdata(pdev, od);
+	}
+
+	dev_info(&pdev->dev, "OMAP DMA engine driver\n");
+
+	return rc;
+}
+
+static int omap_dma_remove(struct platform_device *pdev)
+{
+	struct omap_dmadev *od = platform_get_drvdata(pdev);
+
+	dma_async_device_unregister(&od->ddev);
+	omap_dma_free(od);
+
+	return 0;
+}
+
+static struct platform_driver omap_dma_driver = {
+	.probe	= omap_dma_probe,
+	.remove	= omap_dma_remove,
+	.driver = {
+		.name = "omap-dma-engine",
+		.owner = THIS_MODULE,
+	},
+};
+
+bool omap_dma_filter_fn(struct dma_chan *chan, void *param)
+{
+	if (chan->device->dev->driver == &omap_dma_driver.driver) {
+		struct omap_chan *c = to_omap_dma_chan(chan);
+		unsigned req = *(unsigned *)param;
+
+		return req == c->dma_sig;
+	}
+	return false;
+}
+EXPORT_SYMBOL_GPL(omap_dma_filter_fn);
+
+static struct platform_device *pdev;
+
+static const struct platform_device_info omap_dma_dev_info = {
+	.name = "omap-dma-engine",
+	.id = -1,
+	.dma_mask = DMA_BIT_MASK(32),
+};
+
+static int omap_dma_init(void)
+{
+	int rc = platform_driver_register(&omap_dma_driver);
+
+	if (rc == 0) {
+		pdev = platform_device_register_full(&omap_dma_dev_info);
+		if (IS_ERR(pdev)) {
+			platform_driver_unregister(&omap_dma_driver);
+			rc = PTR_ERR(pdev);
+		}
+	}
+	return rc;
+}
+subsys_initcall(omap_dma_init);
+
+static void __exit omap_dma_exit(void)
+{
+	platform_device_unregister(pdev);
+	platform_driver_unregister(&omap_dma_driver);
+}
+module_exit(omap_dma_exit);
+
+MODULE_AUTHOR("Russell King");
+MODULE_LICENSE("GPL");

include/linux/omap-dma.h

@@ -0,0 +1,22 @@
+/*
+ * OMAP DMA Engine support
+ *
+ * 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.
+ */
+#ifndef __LINUX_OMAP_DMA_H
+#define __LINUX_OMAP_DMA_H
+
+struct dma_chan;
+
+#if defined(CONFIG_DMA_OMAP) || defined(CONFIG_DMA_OMAP_MODULE)
+bool omap_dma_filter_fn(struct dma_chan *, void *);
+#else
+static inline bool omap_dma_filter_fn(struct dma_chan *c, void *d)
+{
+	return false;
+}
+#endif
+
+#endif