1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/dma/bcm2708-dmaengine.c b/drivers/dma/bcm2708-dmaengine.c
new file mode 100644
index 000000000000..a9a7f92584c8
--- /dev/null
+++ b/drivers/dma/bcm2708-dmaengine.c
@@ -0,0 +1,281 @@
+/*
+ * BCM2708 legacy DMA API
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/platform_data/dma-bcm2708.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/spinlock.h>
+
+#include "virt-dma.h"
+
+#define CACHE_LINE_MASK 31
+#define DEFAULT_DMACHAN_BITMAP 0x10  /* channel 4 only */
+
+/* valid only for channels 0 - 14, 15 has its own base address */
+#define BCM2708_DMA_CHAN(n)	((n) << 8) /* base address */
+#define BCM2708_DMA_CHANIO(dma_base, n) \
+	((void __iomem *)((char *)(dma_base) + BCM2708_DMA_CHAN(n)))
+
+struct vc_dmaman {
+	void __iomem *dma_base;
+	u32 chan_available; /* bitmap of available channels */
+	u32 has_feature[BCM_DMA_FEATURE_COUNT]; /* bitmap of feature presence */
+	struct mutex lock;
+};
+
+static struct device *dmaman_dev;	/* we assume there's only one! */
+static struct vc_dmaman *g_dmaman;	/* DMA manager */
+
+/* DMA Auxiliary Functions */
+
+/* A DMA buffer on an arbitrary boundary may separate a cache line into a
+   section inside the DMA buffer and another section outside it.
+   Even if we flush DMA buffers from the cache there is always the chance that
+   during a DMA someone will access the part of a cache line that is outside
+   the DMA buffer - which will then bring in unwelcome data.
+   Without being able to dictate our own buffer pools we must insist that
+   DMA buffers consist of a whole number of cache lines.
+*/
+extern int bcm_sg_suitable_for_dma(struct scatterlist *sg_ptr, int sg_len)
+{
+	int i;
+
+	for (i = 0; i < sg_len; i++) {
+		if (sg_ptr[i].offset & CACHE_LINE_MASK ||
+		    sg_ptr[i].length & CACHE_LINE_MASK)
+			return 0;
+	}
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(bcm_sg_suitable_for_dma);
+
+extern void bcm_dma_start(void __iomem *dma_chan_base,
+			  dma_addr_t control_block)
+{
+	dsb(sy);	/* ARM data synchronization (push) operation */
+
+	writel(control_block, dma_chan_base + BCM2708_DMA_ADDR);
+	writel(BCM2708_DMA_ACTIVE, dma_chan_base + BCM2708_DMA_CS);
+}
+EXPORT_SYMBOL_GPL(bcm_dma_start);
+
+extern void bcm_dma_wait_idle(void __iomem *dma_chan_base)
+{
+	dsb(sy);
+
+	/* ugly busy wait only option for now */
+	while (readl(dma_chan_base + BCM2708_DMA_CS) & BCM2708_DMA_ACTIVE)
+		cpu_relax();
+}
+EXPORT_SYMBOL_GPL(bcm_dma_wait_idle);
+
+extern bool bcm_dma_is_busy(void __iomem *dma_chan_base)
+{
+	dsb(sy);
+
+	return readl(dma_chan_base + BCM2708_DMA_CS) & BCM2708_DMA_ACTIVE;
+}
+EXPORT_SYMBOL_GPL(bcm_dma_is_busy);
+
+/* Complete an ongoing DMA (assuming its results are to be ignored)
+   Does nothing if there is no DMA in progress.
+   This routine waits for the current AXI transfer to complete before
+   terminating the current DMA. If the current transfer is hung on a DREQ used
+   by an uncooperative peripheral the AXI transfer may never complete.	In this
+   case the routine times out and return a non-zero error code.
+   Use of this routine doesn't guarantee that the ongoing or aborted DMA
+   does not produce an interrupt.
+*/
+extern int bcm_dma_abort(void __iomem *dma_chan_base)
+{
+	unsigned long int cs;
+	int rc = 0;
+
+	cs = readl(dma_chan_base + BCM2708_DMA_CS);
+
+	if (BCM2708_DMA_ACTIVE & cs) {
+		long int timeout = 10000;
+
+		/* write 0 to the active bit - pause the DMA */
+		writel(0, dma_chan_base + BCM2708_DMA_CS);
+
+		/* wait for any current AXI transfer to complete */
+		while (0 != (cs & BCM2708_DMA_ISPAUSED) && --timeout >= 0)
+			cs = readl(dma_chan_base + BCM2708_DMA_CS);
+
+		if (0 != (cs & BCM2708_DMA_ISPAUSED)) {
+			/* we'll un-pause when we set of our next DMA */
+			rc = -ETIMEDOUT;
+
+		} else if (BCM2708_DMA_ACTIVE & cs) {
+			/* terminate the control block chain */
+			writel(0, dma_chan_base + BCM2708_DMA_NEXTCB);
+
+			/* abort the whole DMA */
+			writel(BCM2708_DMA_ABORT | BCM2708_DMA_ACTIVE,
+			       dma_chan_base + BCM2708_DMA_CS);
+		}
+	}
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(bcm_dma_abort);
+
+ /* DMA Manager Device Methods */
+
+static void vc_dmaman_init(struct vc_dmaman *dmaman, void __iomem *dma_base,
+			   u32 chans_available)
+{
+	dmaman->dma_base = dma_base;
+	dmaman->chan_available = chans_available;
+	dmaman->has_feature[BCM_DMA_FEATURE_FAST_ORD] = 0x0c;  /* 2 & 3 */
+	dmaman->has_feature[BCM_DMA_FEATURE_BULK_ORD] = 0x01;  /* 0 */
+	dmaman->has_feature[BCM_DMA_FEATURE_NORMAL_ORD] = 0xfe;  /* 1 to 7 */
+	dmaman->has_feature[BCM_DMA_FEATURE_LITE_ORD] = 0x7f00;  /* 8 to 14 */
+}
+
+static int vc_dmaman_chan_alloc(struct vc_dmaman *dmaman,
+				unsigned required_feature_set)
+{
+	u32 chans;
+	int chan = 0;
+	int feature;
+
+	chans = dmaman->chan_available;
+	for (feature = 0; feature < BCM_DMA_FEATURE_COUNT; feature++)
+		/* select the subset of available channels with the desired
+		   features */
+		if (required_feature_set & (1 << feature))
+			chans &= dmaman->has_feature[feature];
+
+	if (!chans)
+		return -ENOENT;
+
+	/* return the ordinal of the first channel in the bitmap */
+	while (chans != 0 && (chans & 1) == 0) {
+		chans >>= 1;
+		chan++;
+	}
+	/* claim the channel */
+	dmaman->chan_available &= ~(1 << chan);
+
+	return chan;
+}
+
+static int vc_dmaman_chan_free(struct vc_dmaman *dmaman, int chan)
+{
+	if (chan < 0)
+		return -EINVAL;
+
+	if ((1 << chan) & dmaman->chan_available)
+		return -EIDRM;
+
+	dmaman->chan_available |= (1 << chan);
+
+	return 0;
+}
+
+/* DMA Manager Monitor */
+
+extern int bcm_dma_chan_alloc(unsigned required_feature_set,
+			      void __iomem **out_dma_base, int *out_dma_irq)
+{
+	struct vc_dmaman *dmaman = g_dmaman;
+	struct platform_device *pdev = to_platform_device(dmaman_dev);
+	int chan;
+	int irq;
+
+	if (!dmaman_dev)
+		return -ENODEV;
+
+	mutex_lock(&dmaman->lock);
+	chan = vc_dmaman_chan_alloc(dmaman, required_feature_set);
+	if (chan < 0)
+		goto out;
+
+	irq = platform_get_irq(pdev, (unsigned int)chan);
+	if (irq < 0) {
+		dev_err(dmaman_dev, "failed to get irq for DMA channel %d\n",
+			chan);
+		vc_dmaman_chan_free(dmaman, chan);
+		chan = -ENOENT;
+		goto out;
+	}
+
+	*out_dma_base = BCM2708_DMA_CHANIO(dmaman->dma_base, chan);
+	*out_dma_irq = irq;
+	dev_dbg(dmaman_dev,
+		"Legacy API allocated channel=%d, base=%p, irq=%i\n",
+		chan, *out_dma_base, *out_dma_irq);
+
+out:
+	mutex_unlock(&dmaman->lock);
+
+	return chan;
+}
+EXPORT_SYMBOL_GPL(bcm_dma_chan_alloc);
+
+extern int bcm_dma_chan_free(int channel)
+{
+	struct vc_dmaman *dmaman = g_dmaman;
+	int rc;
+
+	if (!dmaman_dev)
+		return -ENODEV;
+
+	mutex_lock(&dmaman->lock);
+	rc = vc_dmaman_chan_free(dmaman, channel);
+	mutex_unlock(&dmaman->lock);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(bcm_dma_chan_free);
+
+int bcm_dmaman_probe(struct platform_device *pdev, void __iomem *base,
+		     u32 chans_available)
+{
+	struct device *dev = &pdev->dev;
+	struct vc_dmaman *dmaman;
+
+	dmaman = devm_kzalloc(dev, sizeof(*dmaman), GFP_KERNEL);
+	if (!dmaman)
+		return -ENOMEM;
+
+	mutex_init(&dmaman->lock);
+	vc_dmaman_init(dmaman, base, chans_available);
+	g_dmaman = dmaman;
+	dmaman_dev = dev;
+
+	dev_info(dev, "DMA legacy API manager, dmachans=0x%x\n",
+		 chans_available);
+
+	return 0;
+}
+EXPORT_SYMBOL(bcm_dmaman_probe);
+
+int bcm_dmaman_remove(struct platform_device *pdev)
+{
+	dmaman_dev = NULL;
+
+	return 0;
+}
+EXPORT_SYMBOL(bcm_dmaman_remove);
+
+MODULE_LICENSE("GPL");