dmaengine: add TI EDMA DMA engine driver

Add a DMA engine driver for the TI EDMA controller. This driver
is implemented as a wrapper around the existing DaVinci private
DMA implementation. This approach allows for incremental conversion
of each peripheral driver to the DMA engine API. The EDMA driver
supports slave transfers but does not yet support cyclic transfers.

Signed-off-by: Matt Porter <mporter@ti.com>
Tested-by: Tom Rini <trini@ti.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

1 files changed, 671 insertions, 0 deletions

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
new file mode 100644
index 00000000000..05aea3ce850
--- /dev/null
+++ b/drivers/dma/edma.c
@@ -0,0 +1,671 @@
+/*
+ * TI EDMA DMA engine driver
+ *
+ * Copyright 2012 Texas Instruments
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#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/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <mach/edma.h>
+
+#include "dmaengine.h"
+#include "virt-dma.h"
+
+/*
+ * This will go away when the private EDMA API is folded
+ * into this driver and the platform device(s) are
+ * instantiated in the arch code. We can only get away
+ * with this simplification because DA8XX may not be built
+ * in the same kernel image with other DaVinci parts. This
+ * avoids having to sprinkle dmaengine driver platform devices
+ * and data throughout all the existing board files.
+ */
+#ifdef CONFIG_ARCH_DAVINCI_DA8XX
+#define EDMA_CTLRS	2
+#define EDMA_CHANS	32
+#else
+#define EDMA_CTLRS	1
+#define EDMA_CHANS	64
+#endif /* CONFIG_ARCH_DAVINCI_DA8XX */
+
+/* Max of 16 segments per channel to conserve PaRAM slots */
+#define MAX_NR_SG		16
+#define EDMA_MAX_SLOTS		MAX_NR_SG
+#define EDMA_DESCRIPTORS	16
+
+struct edma_desc {
+	struct virt_dma_desc		vdesc;
+	struct list_head		node;
+	int				absync;
+	int				pset_nr;
+	struct edmacc_param		pset[0];
+};
+
+struct edma_cc;
+
+struct edma_chan {
+	struct virt_dma_chan		vchan;
+	struct list_head		node;
+	struct edma_desc		*edesc;
+	struct edma_cc			*ecc;
+	int				ch_num;
+	bool				alloced;
+	int				slot[EDMA_MAX_SLOTS];
+	dma_addr_t			addr;
+	int				addr_width;
+	int				maxburst;
+};
+
+struct edma_cc {
+	int				ctlr;
+	struct dma_device		dma_slave;
+	struct edma_chan		slave_chans[EDMA_CHANS];
+	int				num_slave_chans;
+	int				dummy_slot;
+};
+
+static inline struct edma_cc *to_edma_cc(struct dma_device *d)
+{
+	return container_of(d, struct edma_cc, dma_slave);
+}
+
+static inline struct edma_chan *to_edma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct edma_chan, vchan.chan);
+}
+
+static inline struct edma_desc
+*to_edma_desc(struct dma_async_tx_descriptor *tx)
+{
+	return container_of(tx, struct edma_desc, vdesc.tx);
+}
+
+static void edma_desc_free(struct virt_dma_desc *vdesc)
+{
+	kfree(container_of(vdesc, struct edma_desc, vdesc));
+}
+
+/* Dispatch a queued descriptor to the controller (caller holds lock) */
+static void edma_execute(struct edma_chan *echan)
+{
+	struct virt_dma_desc *vdesc = vchan_next_desc(&echan->vchan);
+	struct edma_desc *edesc;
+	int i;
+
+	if (!vdesc) {
+		echan->edesc = NULL;
+		return;
+	}
+
+	list_del(&vdesc->node);
+
+	echan->edesc = edesc = to_edma_desc(&vdesc->tx);
+
+	/* Write descriptor PaRAM set(s) */
+	for (i = 0; i < edesc->pset_nr; i++) {
+		edma_write_slot(echan->slot[i], &edesc->pset[i]);
+		dev_dbg(echan->vchan.chan.device->dev,
+			"\n pset[%d]:\n"
+			"  chnum\t%d\n"
+			"  slot\t%d\n"
+			"  opt\t%08x\n"
+			"  src\t%08x\n"
+			"  dst\t%08x\n"
+			"  abcnt\t%08x\n"
+			"  ccnt\t%08x\n"
+			"  bidx\t%08x\n"
+			"  cidx\t%08x\n"
+			"  lkrld\t%08x\n",
+			i, echan->ch_num, echan->slot[i],
+			edesc->pset[i].opt,
+			edesc->pset[i].src,
+			edesc->pset[i].dst,
+			edesc->pset[i].a_b_cnt,
+			edesc->pset[i].ccnt,
+			edesc->pset[i].src_dst_bidx,
+			edesc->pset[i].src_dst_cidx,
+			edesc->pset[i].link_bcntrld);
+		/* Link to the previous slot if not the last set */
+		if (i != (edesc->pset_nr - 1))
+			edma_link(echan->slot[i], echan->slot[i+1]);
+		/* Final pset links to the dummy pset */
+		else
+			edma_link(echan->slot[i], echan->ecc->dummy_slot);
+	}
+
+	edma_start(echan->ch_num);
+}
+
+static int edma_terminate_all(struct edma_chan *echan)
+{
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&echan->vchan.lock, flags);
+
+	/*
+	 * Stop DMA activity: we assume the callback will not be called
+	 * after edma_dma() returns (even if it does, it will see
+	 * echan->edesc is NULL and exit.)
+	 */
+	if (echan->edesc) {
+		echan->edesc = NULL;
+		edma_stop(echan->ch_num);
+	}
+
+	vchan_get_all_descriptors(&echan->vchan, &head);
+	spin_unlock_irqrestore(&echan->vchan.lock, flags);
+	vchan_dma_desc_free_list(&echan->vchan, &head);
+
+	return 0;
+}
+
+
+static int edma_slave_config(struct edma_chan *echan,
+	struct dma_slave_config *config)
+{
+	if ((config->src_addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES) ||
+	    (config->dst_addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES))
+		return -EINVAL;
+
+	if (config->direction == DMA_MEM_TO_DEV) {
+		if (config->dst_addr)
+			echan->addr = config->dst_addr;
+		if (config->dst_addr_width)
+			echan->addr_width = config->dst_addr_width;
+		if (config->dst_maxburst)
+			echan->maxburst = config->dst_maxburst;
+	} else if (config->direction == DMA_DEV_TO_MEM) {
+		if (config->src_addr)
+			echan->addr = config->src_addr;
+		if (config->src_addr_width)
+			echan->addr_width = config->src_addr_width;
+		if (config->src_maxburst)
+			echan->maxburst = config->src_maxburst;
+	}
+
+	return 0;
+}
+
+static int edma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+			unsigned long arg)
+{
+	int ret = 0;
+	struct dma_slave_config *config;
+	struct edma_chan *echan = to_edma_chan(chan);
+
+	switch (cmd) {
+	case DMA_TERMINATE_ALL:
+		edma_terminate_all(echan);
+		break;
+	case DMA_SLAVE_CONFIG:
+		config = (struct dma_slave_config *)arg;
+		ret = edma_slave_config(echan, config);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	return ret;
+}
+
+static struct dma_async_tx_descriptor *edma_prep_slave_sg(
+	struct dma_chan *chan, struct scatterlist *sgl,
+	unsigned int sg_len, enum dma_transfer_direction direction,
+	unsigned long tx_flags, void *context)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct device *dev = chan->device->dev;
+	struct edma_desc *edesc;
+	struct scatterlist *sg;
+	int i;
+	int acnt, bcnt, ccnt, src, dst, cidx;
+	int src_bidx, dst_bidx, src_cidx, dst_cidx;
+
+	if (unlikely(!echan || !sgl || !sg_len))
+		return NULL;
+
+	if (echan->addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) {
+		dev_err(dev, "Undefined slave buswidth\n");
+		return NULL;
+	}
+
+	if (sg_len > MAX_NR_SG) {
+		dev_err(dev, "Exceeded max SG segments %d > %d\n",
+			sg_len, MAX_NR_SG);
+		return NULL;
+	}
+
+	edesc = kzalloc(sizeof(*edesc) + sg_len *
+		sizeof(edesc->pset[0]), GFP_ATOMIC);
+	if (!edesc) {
+		dev_dbg(dev, "Failed to allocate a descriptor\n");
+		return NULL;
+	}
+
+	edesc->pset_nr = sg_len;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		/* Allocate a PaRAM slot, if needed */
+		if (echan->slot[i] < 0) {
+			echan->slot[i] =
+				edma_alloc_slot(EDMA_CTLR(echan->ch_num),
+						EDMA_SLOT_ANY);
+			if (echan->slot[i] < 0) {
+				dev_err(dev, "Failed to allocate slot\n");
+				return NULL;
+			}
+		}
+
+		acnt = echan->addr_width;
+
+		/*
+		 * If the maxburst is equal to the fifo width, use
+		 * A-synced transfers. This allows for large contiguous
+		 * buffer transfers using only one PaRAM set.
+		 */
+		if (echan->maxburst == 1) {
+			edesc->absync = false;
+			ccnt = sg_dma_len(sg) / acnt / (SZ_64K - 1);
+			bcnt = sg_dma_len(sg) / acnt - ccnt * (SZ_64K - 1);
+			if (bcnt)
+				ccnt++;
+			else
+				bcnt = SZ_64K - 1;
+			cidx = acnt;
+		/*
+		 * If maxburst is greater than the fifo address_width,
+		 * use AB-synced transfers where A count is the fifo
+		 * address_width and B count is the maxburst. In this
+		 * case, we are limited to transfers of C count frames
+		 * of (address_width * maxburst) where C count is limited
+		 * to SZ_64K-1. This places an upper bound on the length
+		 * of an SG segment that can be handled.
+		 */
+		} else {
+			edesc->absync = true;
+			bcnt = echan->maxburst;
+			ccnt = sg_dma_len(sg) / (acnt * bcnt);
+			if (ccnt > (SZ_64K - 1)) {
+				dev_err(dev, "Exceeded max SG segment size\n");
+				return NULL;
+			}
+			cidx = acnt * bcnt;
+		}
+
+		if (direction == DMA_MEM_TO_DEV) {
+			src = sg_dma_address(sg);
+			dst = echan->addr;
+			src_bidx = acnt;
+			src_cidx = cidx;
+			dst_bidx = 0;
+			dst_cidx = 0;
+		} else {
+			src = echan->addr;
+			dst = sg_dma_address(sg);
+			src_bidx = 0;
+			src_cidx = 0;
+			dst_bidx = acnt;
+			dst_cidx = cidx;
+		}
+
+		edesc->pset[i].opt = EDMA_TCC(EDMA_CHAN_SLOT(echan->ch_num));
+		/* Configure A or AB synchronized transfers */
+		if (edesc->absync)
+			edesc->pset[i].opt |= SYNCDIM;
+		/* If this is the last set, enable completion interrupt flag */
+		if (i == sg_len - 1)
+			edesc->pset[i].opt |= TCINTEN;
+
+		edesc->pset[i].src = src;
+		edesc->pset[i].dst = dst;
+
+		edesc->pset[i].src_dst_bidx = (dst_bidx << 16) | src_bidx;
+		edesc->pset[i].src_dst_cidx = (dst_cidx << 16) | src_cidx;
+
+		edesc->pset[i].a_b_cnt = bcnt << 16 | acnt;
+		edesc->pset[i].ccnt = ccnt;
+		edesc->pset[i].link_bcntrld = 0xffffffff;
+
+	}
+
+	return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
+}
+
+static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
+{
+	struct edma_chan *echan = data;
+	struct device *dev = echan->vchan.chan.device->dev;
+	struct edma_desc *edesc;
+	unsigned long flags;
+
+	/* Stop the channel */
+	edma_stop(echan->ch_num);
+
+	switch (ch_status) {
+	case DMA_COMPLETE:
+		dev_dbg(dev, "transfer complete on channel %d\n", ch_num);
+
+		spin_lock_irqsave(&echan->vchan.lock, flags);
+
+		edesc = echan->edesc;
+		if (edesc) {
+			edma_execute(echan);
+			vchan_cookie_complete(&edesc->vdesc);
+		}
+
+		spin_unlock_irqrestore(&echan->vchan.lock, flags);
+
+		break;
+	case DMA_CC_ERROR:
+		dev_dbg(dev, "transfer error on channel %d\n", ch_num);
+		break;
+	default:
+		break;
+	}
+}
+
+/* Alloc channel resources */
+static int edma_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct device *dev = chan->device->dev;
+	int ret;
+	int a_ch_num;
+	LIST_HEAD(descs);
+
+	a_ch_num = edma_alloc_channel(echan->ch_num, edma_callback,
+					chan, EVENTQ_DEFAULT);
+
+	if (a_ch_num < 0) {
+		ret = -ENODEV;
+		goto err_no_chan;
+	}
+
+	if (a_ch_num != echan->ch_num) {
+		dev_err(dev, "failed to allocate requested channel %u:%u\n",
+			EDMA_CTLR(echan->ch_num),
+			EDMA_CHAN_SLOT(echan->ch_num));
+		ret = -ENODEV;
+		goto err_wrong_chan;
+	}
+
+	echan->alloced = true;
+	echan->slot[0] = echan->ch_num;
+
+	dev_info(dev, "allocated channel for %u:%u\n",
+		 EDMA_CTLR(echan->ch_num), EDMA_CHAN_SLOT(echan->ch_num));
+
+	return 0;
+
+err_wrong_chan:
+	edma_free_channel(a_ch_num);
+err_no_chan:
+	return ret;
+}
+
+/* Free channel resources */
+static void edma_free_chan_resources(struct dma_chan *chan)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct device *dev = chan->device->dev;
+	int i;
+
+	/* Terminate transfers */
+	edma_stop(echan->ch_num);
+
+	vchan_free_chan_resources(&echan->vchan);
+
+	/* Free EDMA PaRAM slots */
+	for (i = 1; i < EDMA_MAX_SLOTS; i++) {
+		if (echan->slot[i] >= 0) {
+			edma_free_slot(echan->slot[i]);
+			echan->slot[i] = -1;
+		}
+	}
+
+	/* Free EDMA channel */
+	if (echan->alloced) {
+		edma_free_channel(echan->ch_num);
+		echan->alloced = false;
+	}
+
+	dev_info(dev, "freeing channel for %u\n", echan->ch_num);
+}
+
+/* Send pending descriptor to hardware */
+static void edma_issue_pending(struct dma_chan *chan)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&echan->vchan.lock, flags);
+	if (vchan_issue_pending(&echan->vchan) && !echan->edesc)
+		edma_execute(echan);
+	spin_unlock_irqrestore(&echan->vchan.lock, flags);
+}
+
+static size_t edma_desc_size(struct edma_desc *edesc)
+{
+	int i;
+	size_t size;
+
+	if (edesc->absync)
+		for (size = i = 0; i < edesc->pset_nr; i++)
+			size += (edesc->pset[i].a_b_cnt & 0xffff) *
+				(edesc->pset[i].a_b_cnt >> 16) *
+				 edesc->pset[i].ccnt;
+	else
+		size = (edesc->pset[0].a_b_cnt & 0xffff) *
+			(edesc->pset[0].a_b_cnt >> 16) +
+			(edesc->pset[0].a_b_cnt & 0xffff) *
+			(SZ_64K - 1) * edesc->pset[0].ccnt;
+
+	return size;
+}
+
+/* Check request completion status */
+static enum dma_status edma_tx_status(struct dma_chan *chan,
+				      dma_cookie_t cookie,
+				      struct dma_tx_state *txstate)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct virt_dma_desc *vdesc;
+	enum dma_status ret;
+	unsigned long flags;
+
+	ret = dma_cookie_status(chan, cookie, txstate);
+	if (ret == DMA_SUCCESS || !txstate)
+		return ret;
+
+	spin_lock_irqsave(&echan->vchan.lock, flags);
+	vdesc = vchan_find_desc(&echan->vchan, cookie);
+	if (vdesc) {
+		txstate->residue = edma_desc_size(to_edma_desc(&vdesc->tx));
+	} else if (echan->edesc && echan->edesc->vdesc.tx.cookie == cookie) {
+		struct edma_desc *edesc = echan->edesc;
+		txstate->residue = edma_desc_size(edesc);
+	} else {
+		txstate->residue = 0;
+	}
+	spin_unlock_irqrestore(&echan->vchan.lock, flags);
+
+	return ret;
+}
+
+static void __init edma_chan_init(struct edma_cc *ecc,
+				  struct dma_device *dma,
+				  struct edma_chan *echans)
+{
+	int i, j;
+
+	for (i = 0; i < EDMA_CHANS; i++) {
+		struct edma_chan *echan = &echans[i];
+		echan->ch_num = EDMA_CTLR_CHAN(ecc->ctlr, i);
+		echan->ecc = ecc;
+		echan->vchan.desc_free = edma_desc_free;
+
+		vchan_init(&echan->vchan, dma);
+
+		INIT_LIST_HEAD(&echan->node);
+		for (j = 0; j < EDMA_MAX_SLOTS; j++)
+			echan->slot[j] = -1;
+	}
+}
+
+static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
+			  struct device *dev)
+{
+	dma->device_prep_slave_sg = edma_prep_slave_sg;
+	dma->device_alloc_chan_resources = edma_alloc_chan_resources;
+	dma->device_free_chan_resources = edma_free_chan_resources;
+	dma->device_issue_pending = edma_issue_pending;
+	dma->device_tx_status = edma_tx_status;
+	dma->device_control = edma_control;
+	dma->dev = dev;
+
+	INIT_LIST_HEAD(&dma->channels);
+}
+
+static int __devinit edma_probe(struct platform_device *pdev)
+{
+	struct edma_cc *ecc;
+	int ret;
+
+	ecc = devm_kzalloc(&pdev->dev, sizeof(*ecc), GFP_KERNEL);
+	if (!ecc) {
+		dev_err(&pdev->dev, "Can't allocate controller\n");
+		return -ENOMEM;
+	}
+
+	ecc->ctlr = pdev->id;
+	ecc->dummy_slot = edma_alloc_slot(ecc->ctlr, EDMA_SLOT_ANY);
+	if (ecc->dummy_slot < 0) {
+		dev_err(&pdev->dev, "Can't allocate PaRAM dummy slot\n");
+		return -EIO;
+	}
+
+	dma_cap_zero(ecc->dma_slave.cap_mask);
+	dma_cap_set(DMA_SLAVE, ecc->dma_slave.cap_mask);
+
+	edma_dma_init(ecc, &ecc->dma_slave, &pdev->dev);
+
+	edma_chan_init(ecc, &ecc->dma_slave, ecc->slave_chans);
+
+	ret = dma_async_device_register(&ecc->dma_slave);
+	if (ret)
+		goto err_reg1;
+
+	platform_set_drvdata(pdev, ecc);
+
+	dev_info(&pdev->dev, "TI EDMA DMA engine driver\n");
+
+	return 0;
+
+err_reg1:
+	edma_free_slot(ecc->dummy_slot);
+	return ret;
+}
+
+static int __devexit edma_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct edma_cc *ecc = dev_get_drvdata(dev);
+
+	dma_async_device_unregister(&ecc->dma_slave);
+	edma_free_slot(ecc->dummy_slot);
+
+	return 0;
+}
+
+static struct platform_driver edma_driver = {
+	.probe		= edma_probe,
+	.remove		= __devexit_p(edma_remove),
+	.driver = {
+		.name = "edma-dma-engine",
+		.owner = THIS_MODULE,
+	},
+};
+
+bool edma_filter_fn(struct dma_chan *chan, void *param)
+{
+	if (chan->device->dev->driver == &edma_driver.driver) {
+		struct edma_chan *echan = to_edma_chan(chan);
+		unsigned ch_req = *(unsigned *)param;
+		return ch_req == echan->ch_num;
+	}
+	return false;
+}
+EXPORT_SYMBOL(edma_filter_fn);
+
+static struct platform_device *pdev0, *pdev1;
+
+static const struct platform_device_info edma_dev_info0 = {
+	.name = "edma-dma-engine",
+	.id = 0,
+	.dma_mask = DMA_BIT_MASK(32),
+};
+
+static const struct platform_device_info edma_dev_info1 = {
+	.name = "edma-dma-engine",
+	.id = 1,
+	.dma_mask = DMA_BIT_MASK(32),
+};
+
+static int edma_init(void)
+{
+	int ret = platform_driver_register(&edma_driver);
+
+	if (ret == 0) {
+		pdev0 = platform_device_register_full(&edma_dev_info0);
+		if (IS_ERR(pdev0)) {
+			platform_driver_unregister(&edma_driver);
+			ret = PTR_ERR(pdev0);
+			goto out;
+		}
+	}
+
+	if (EDMA_CTLRS == 2) {
+		pdev1 = platform_device_register_full(&edma_dev_info1);
+		if (IS_ERR(pdev1)) {
+			platform_driver_unregister(&edma_driver);
+			platform_device_unregister(pdev0);
+			ret = PTR_ERR(pdev1);
+		}
+	}
+
+out:
+	return ret;
+}
+subsys_initcall(edma_init);
+
+static void __exit edma_exit(void)
+{
+	platform_device_unregister(pdev0);
+	if (pdev1)
+		platform_device_unregister(pdev1);
+	platform_driver_unregister(&edma_driver);
+}
+module_exit(edma_exit);
+
+MODULE_AUTHOR("Matt Porter <mporter@ti.com>");
+MODULE_DESCRIPTION("TI EDMA DMA engine driver");
+MODULE_LICENSE("GPL v2");