From 54def9a915b32cc162e77d8ce0f67da51fac5969 Mon Sep 17 00:00:00 2001
From: Florian Meier <florian.meier@koalo.de>
Date: Fri, 22 Nov 2013 14:22:53 +0100
Subject: [PATCH] dmaengine: Add support for BCM2708
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Add support for DMA controller of BCM2708 as used in the Raspberry Pi.
Currently it only supports cyclic DMA.

Signed-off-by: Florian Meier <florian.meier@koalo.de>

dmaengine: expand functionality by supporting scatter/gather transfers sdhci-bcm2708 and dma.c: fix for LITE channels

DMA: fix cyclic LITE length overflow bug

dmaengine: bcm2708: Remove chancnt affectations

Mirror bcm2835-dma.c commit 9eba5536a7434c69d8c185d4bd1c70734d92287d:
chancnt is already filled by dma_async_device_register, which uses the channel
list to know how much channels there is.

Since it's already filled, we can safely remove it from the drivers' probe
function.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

dmaengine: bcm2708: overwrite dreq only if it is not set

dreq is set when the DMA channel is fetched from Device Tree.
slave_id is set using dmaengine_slave_config().
Only overwrite dreq with slave_id if it is not set.

dreq/slave_id in the cyclic DMA case is not touched, because I don't
have hardware to test with.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

dmaengine: bcm2708: do device registration in the board file

Don't register the device in the driver. Do it in the board file.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

dmaengine: bcm2708: don't restrict DT support to ARCH_BCM2835

Both ARCH_BCM2835 and ARCH_BCM270x are built with OF now.
Add Device Tree support to the non ARCH_BCM2835 case.
Use the same driver name regardless of architecture.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

BCM270x_DT: add bcm2835-dma entry

Add Device Tree entry for bcm2835-dma.
The entry doesn't contain any resources since they are handled
by the arch/arm/mach-bcm270x/dma.c driver.
In non-DT mode, don't add the device in the board file.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

bcm2708-dmaengine: Add debug options

BCM270x: Add memory and irq resources to dmaengine device and DT

Prepare for merging of the legacy DMA API arch driver dma.c
with bcm2708-dmaengine by adding memory and irq resources both
to platform file device and Device Tree node.
Don't use BCM_DMAMAN_DRIVER_NAME so we don't have to include mach/dma.h

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

dmaengine: bcm2708: Merge with arch dma.c driver and disable dma.c

Merge the legacy DMA API driver with bcm2708-dmaengine.
This is done so we can use bcm2708_fb on ARCH_BCM2835 (mailbox
driver is also needed).

Changes to the dma.c code:
- Use BIT() macro.
- Cutdown some comments to one line.
- Add mutex to vc_dmaman and use this, since the dev lock is locked
  during probing of the engine part.
- Add global g_dmaman variable since drvdata is used by the engine part.
- Restructure for readability:
  vc_dmaman_chan_alloc()
  vc_dmaman_chan_free()
  bcm_dma_chan_free()
- Restructure bcm_dma_chan_alloc() to simplify error handling.
- Use device irq resources instead of hardcoded bcm_dma_irqs table.
- Remove dev_dmaman_register() and code it directly.
- Remove dev_dmaman_deregister() and code it directly.
- Simplify bcm_dmaman_probe() using devm_* functions.
- Get dmachans from DT if available.
- Keep 'dma.dmachans' module argument name for backwards compatibility.

Make it available on ARCH_BCM2835 as well.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

dmaengine: bcm2708: set residue_granularity field

bcm2708-dmaengine supports residue reporting at burst level
but didn't report this via the residue_granularity field.

Without this field set properly we get playback issues with I2S cards.

dmaengine: bcm2708-dmaengine: Fix memory leak when stopping a running transfer

bcm2708-dmaengine: Use more DMA channels (but not 12)

1) Only the bcm2708_fb drivers uses the legacy DMA API, and
it requires a BULK-capable channel, so all other types
(FAST, NORMAL and LITE) can be made available to the regular
DMA API.

2) DMA channels 11-14 share an interrupt. The driver can't
handle this, so don't use channels 12-14 (12 was used, probably
because it appears to have an interrupt, but in reality that
interrupt is for activity on ANY channel). This may explain
a lockup encountered when running out of DMA channels.

The combined effect of this patch is to leave 7 DMA channels
available + channel 0 for bcm2708_fb via the legacy API.

See: https://github.com/raspberrypi/linux/issues/1110
     https://github.com/raspberrypi/linux/issues/1108

dmaengine: bcm2708: Make legacy API available for bcm2835-dma

bcm2708_fb uses the legacy DMA API, so in order to start using
bcm2835-dma, bcm2835-dma has to support the legacy API. Make this
possible by exporting bcm_dmaman_probe() and bcm_dmaman_remove().

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

dmaengine: bcm2708: Change DT compatible string

Both bcm2835-dma and bcm2708-dmaengine have the same compatible string.
So change compatible to "brcm,bcm2708-dma".

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>

dmaengine: bcm2708: Remove driver but keep legacy API

Dropping non-DT support means we don't need this driver,
but we still need the legacy DMA API.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
---
 drivers/dma/Kconfig                       |   4 +
 drivers/dma/Makefile                      |   1 +
 drivers/dma/bcm2708-dmaengine.c           | 281 ++++++++++++++++++++++++++++++
 include/linux/platform_data/dma-bcm2708.h | 143 +++++++++++++++
 4 files changed, 429 insertions(+)
 create mode 100644 drivers/dma/bcm2708-dmaengine.c
 create mode 100644 include/linux/platform_data/dma-bcm2708.h

--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -470,6 +470,10 @@ config TIMB_DMA
 	help
 	  Enable support for the Timberdale FPGA DMA engine.
 
+config DMA_BCM2708
+	tristate "BCM2708 DMA legacy API support"
+	depends on DMA_BCM2835
+
 config TI_CPPI41
 	tristate "AM33xx CPPI41 DMA support"
 	depends on ARCH_OMAP
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
 obj-$(CONFIG_AT_XDMAC) += at_xdmac.o
 obj-$(CONFIG_AXI_DMAC) += dma-axi-dmac.o
 obj-$(CONFIG_COH901318) += coh901318.o coh901318_lli.o
+obj-$(CONFIG_DMA_BCM2708) += bcm2708-dmaengine.o
 obj-$(CONFIG_DMA_BCM2835) += bcm2835-dma.o
 obj-$(CONFIG_DMA_JZ4740) += dma-jz4740.o
 obj-$(CONFIG_DMA_JZ4780) += dma-jz4780.o
--- /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();	/* 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();
+
+	/* 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();
+
+	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);
+	struct resource *r;
+	int chan;
+
+	if (!dmaman_dev)
+		return -ENODEV;
+
+	mutex_lock(&dmaman->lock);
+	chan = vc_dmaman_chan_alloc(dmaman, required_feature_set);
+	if (chan < 0)
+		goto out;
+
+	r = platform_get_resource(pdev, IORESOURCE_IRQ, (unsigned int)chan);
+	if (!r) {
+		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 = r->start;
+	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 at %p, dmachans=0x%x\n",
+		 base, 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");
--- /dev/null
+++ b/include/linux/platform_data/dma-bcm2708.h
@@ -0,0 +1,143 @@
+/*
+ *  Copyright (C) 2010 Broadcom
+ *
+ * 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 _PLAT_BCM2708_DMA_H
+#define _PLAT_BCM2708_DMA_H
+
+/* DMA CS Control and Status bits */
+#define BCM2708_DMA_ACTIVE	BIT(0)
+#define BCM2708_DMA_INT		BIT(2)
+#define BCM2708_DMA_ISPAUSED	BIT(4)  /* Pause requested or not active */
+#define BCM2708_DMA_ISHELD	BIT(5)  /* Is held by DREQ flow control */
+#define BCM2708_DMA_ERR		BIT(8)
+#define BCM2708_DMA_ABORT	BIT(30) /* stop current CB, go to next, WO */
+#define BCM2708_DMA_RESET	BIT(31) /* WO, self clearing */
+
+/* DMA control block "info" field bits */
+#define BCM2708_DMA_INT_EN	BIT(0)
+#define BCM2708_DMA_TDMODE	BIT(1)
+#define BCM2708_DMA_WAIT_RESP	BIT(3)
+#define BCM2708_DMA_D_INC	BIT(4)
+#define BCM2708_DMA_D_WIDTH	BIT(5)
+#define BCM2708_DMA_D_DREQ	BIT(6)
+#define BCM2708_DMA_S_INC	BIT(8)
+#define BCM2708_DMA_S_WIDTH	BIT(9)
+#define BCM2708_DMA_S_DREQ	BIT(10)
+
+#define	BCM2708_DMA_BURST(x)	(((x) & 0xf) << 12)
+#define	BCM2708_DMA_PER_MAP(x)	((x) << 16)
+#define	BCM2708_DMA_WAITS(x)	(((x) & 0x1f) << 21)
+
+#define BCM2708_DMA_DREQ_EMMC	11
+#define BCM2708_DMA_DREQ_SDHOST	13
+
+#define BCM2708_DMA_CS		0x00 /* Control and Status */
+#define BCM2708_DMA_ADDR	0x04
+/* the current control block appears in the following registers - read only */
+#define BCM2708_DMA_INFO	0x08
+#define BCM2708_DMA_SOURCE_AD	0x0c
+#define BCM2708_DMA_DEST_AD	0x10
+#define BCM2708_DMA_NEXTCB	0x1C
+#define BCM2708_DMA_DEBUG	0x20
+
+#define BCM2708_DMA4_CS		(BCM2708_DMA_CHAN(4) + BCM2708_DMA_CS)
+#define BCM2708_DMA4_ADDR	(BCM2708_DMA_CHAN(4) + BCM2708_DMA_ADDR)
+
+#define BCM2708_DMA_TDMODE_LEN(w, h) ((h) << 16 | (w))
+
+/* When listing features we can ask for when allocating DMA channels give
+   those with higher priority smaller ordinal numbers */
+#define BCM_DMA_FEATURE_FAST_ORD	0
+#define BCM_DMA_FEATURE_BULK_ORD	1
+#define BCM_DMA_FEATURE_NORMAL_ORD	2
+#define BCM_DMA_FEATURE_LITE_ORD	3
+#define BCM_DMA_FEATURE_FAST		BIT(BCM_DMA_FEATURE_FAST_ORD)
+#define BCM_DMA_FEATURE_BULK		BIT(BCM_DMA_FEATURE_BULK_ORD)
+#define BCM_DMA_FEATURE_NORMAL		BIT(BCM_DMA_FEATURE_NORMAL_ORD)
+#define BCM_DMA_FEATURE_LITE		BIT(BCM_DMA_FEATURE_LITE_ORD)
+#define BCM_DMA_FEATURE_COUNT		4
+
+struct bcm2708_dma_cb {
+	unsigned long info;
+	unsigned long src;
+	unsigned long dst;
+	unsigned long length;
+	unsigned long stride;
+	unsigned long next;
+	unsigned long pad[2];
+};
+
+struct scatterlist;
+struct platform_device;
+
+#ifdef CONFIG_DMA_BCM2708
+
+int bcm_sg_suitable_for_dma(struct scatterlist *sg_ptr, int sg_len);
+void bcm_dma_start(void __iomem *dma_chan_base, dma_addr_t control_block);
+void bcm_dma_wait_idle(void __iomem *dma_chan_base);
+bool bcm_dma_is_busy(void __iomem *dma_chan_base);
+int bcm_dma_abort(void __iomem *dma_chan_base);
+
+/* return channel no or -ve error */
+int bcm_dma_chan_alloc(unsigned preferred_feature_set,
+		       void __iomem **out_dma_base, int *out_dma_irq);
+int bcm_dma_chan_free(int channel);
+
+int bcm_dmaman_probe(struct platform_device *pdev, void __iomem *base,
+		     u32 chans_available);
+int bcm_dmaman_remove(struct platform_device *pdev);
+
+#else /* CONFIG_DMA_BCM2708 */
+
+static inline int bcm_sg_suitable_for_dma(struct scatterlist *sg_ptr,
+					  int sg_len)
+{
+	return 0;
+}
+
+static inline void bcm_dma_start(void __iomem *dma_chan_base,
+				 dma_addr_t control_block) { }
+
+static inline void bcm_dma_wait_idle(void __iomem *dma_chan_base) { }
+
+static inline bool bcm_dma_is_busy(void __iomem *dma_chan_base)
+{
+	return false;
+}
+
+static inline int bcm_dma_abort(void __iomem *dma_chan_base)
+{
+	return -EINVAL;
+}
+
+static inline int bcm_dma_chan_alloc(unsigned preferred_feature_set,
+				     void __iomem **out_dma_base,
+				     int *out_dma_irq)
+{
+	return -EINVAL;
+}
+
+static inline int bcm_dma_chan_free(int channel)
+{
+	return -EINVAL;
+}
+
+static inline int bcm_dmaman_probe(struct platform_device *pdev,
+				   void __iomem *base, u32 chans_available)
+{
+	return 0;
+}
+
+static inline int bcm_dmaman_remove(struct platform_device *pdev)
+{
+	return 0;
+}
+
+#endif /* CONFIG_DMA_BCM2708 */
+
+#endif /* _PLAT_BCM2708_DMA_H */
