dmaengine: Add support for BCM2708

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 9eba553: 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: #1110 #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> bcm2708-dmaengine - Fix arm64 portability/build issues dma-bcm2708: Fix module compilation of CONFIG_DMA_BCM2708 bcm2708-dmaengine.c defines functions like bcm_dma_start which are defined as well in dma-bcm2708.h as inline versions when CONFIG_DMA_BCM2708 is not defined. This works fine when CONFIG_DMA_BCM2708 is built in, but when it is selected as module build fails with redefinition errors because in the build system when CONFIG_DMA_BCM2708 is selected as module, the macro becomes CONFIG_DMA_BCM2708_MODULE. This patch makes the header use CONFIG_DMA_BCM2708_MODULE too when available. Fixes #2056 Signed-off-by: Andrei Gherzan <andrei@gherzan.com> bcm2708-dmaengine: Use platform_get_irq The platform driver framework no longer creates IRQ resources for platform devices because they are expected to use platform_get_irq. This causes the bcm2808_fb acceleration to fail. Fix the problem by calling platform_get_irq as intended. See: #5131 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
raspberrypi · Nov 18, 2024 · f622e0e · f622e0e
1 parent 6d326d2
commit f622e0e
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diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
@@ -136,7 +136,7 @@ config BCM_SBA_RAID
 
 config DMA_BCM2835
 	tristate "BCM2835 DMA engine support"
-	depends on ARCH_BCM2835 || ARCH_BCM2708 || ARCH_BCM2709
+	depends on ARCH_BCM2835
 	select DMA_ENGINE
 	select DMA_VIRTUAL_CHANNELS
 
@@ -669,6 +669,10 @@ config UNIPHIER_XDMAC
 	  UniPhier platform. This DMA controller can transfer data from
 	  memory to memory, memory to peripheral and peripheral to memory.
 
+config DMA_BCM2708
+	tristate "BCM2708 DMA legacy API support"
+	depends on DMA_BCM2835
+
 config XGENE_DMA
 	tristate "APM X-Gene DMA support"
 	depends on ARCH_XGENE || COMPILE_TEST

diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
 obj-$(CONFIG_AT_XDMAC) += at_xdmac.o
 obj-$(CONFIG_AXI_DMAC) += dma-axi-dmac.o
 obj-$(CONFIG_BCM_SBA_RAID) += bcm-sba-raid.o
+obj-$(CONFIG_DMA_BCM2708) += bcm2708-dmaengine.o
 obj-$(CONFIG_DMA_BCM2835) += bcm2835-dma.o
 obj-$(CONFIG_DMA_JZ4780) += dma-jz4780.o
 obj-$(CONFIG_DMA_SA11X0) += sa11x0-dma.o

diff --git a/drivers/dma/bcm2708-dmaengine.c 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");