[PATCH v3 4/4] dmaengine: add driver for Sophgo CV18XX/SG200X dmamux

[Inochi Amaoto <inochiama@outlook.com>]

Sophgo CV18XX/SG200X use DW AXI CORE with a multiplexer for remapping
its request lines. The multiplexer supports at most 8 request lines.

Add driver for Sophgo CV18XX/SG200X DMA multiplexer.

Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
---
 drivers/dma/Kconfig         |   9 ++
 drivers/dma/Makefile        |   1 +
 drivers/dma/cv1800-dmamux.c | 232 ++++++++++++++++++++++++++++++++++++
 3 files changed, 242 insertions(+)
 create mode 100644 drivers/dma/cv1800-dmamux.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index e928f2ca0f1e..5220b4eba3a4 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -546,6 +546,15 @@ config PLX_DMA
 	  These are exposed via extra functions on the switch's
 	  upstream port. Each function exposes one DMA channel.

+config SOPHGO_CV1800_DMAMUX
+	tristate "Sophgo CV1800/SG2000 series SoC DMA multiplexer support"
+	depends on MFD_SYSCON
+	depends on ARCH_SOPHGO
+	help
+	  Support for the DMA multiplexer on Sophgo CV1800/SG2000
+	  series SoCs.
+	  Say Y here if your board have this soc.
+
 config STE_DMA40
 	bool "ST-Ericsson DMA40 support"
 	depends on ARCH_U8500
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index dfd40d14e408..7465f249ee47 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_PPC_BESTCOMM) += bestcomm/
 obj-$(CONFIG_PXA_DMA) += pxa_dma.o
 obj-$(CONFIG_RENESAS_DMA) += sh/
 obj-$(CONFIG_SF_PDMA) += sf-pdma/
+obj-$(CONFIG_SOPHGO_CV1800_DMAMUX) += cv1800-dmamux.o
 obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
 obj-$(CONFIG_STM32_DMA) += stm32-dma.o
 obj-$(CONFIG_STM32_DMAMUX) += stm32-dmamux.o
diff --git a/drivers/dma/cv1800-dmamux.c b/drivers/dma/cv1800-dmamux.c
new file mode 100644
index 000000000000..b41c39f2e338
--- /dev/null
+++ b/drivers/dma/cv1800-dmamux.c
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 Inochi Amaoto <inochiama@outlook.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+#include <linux/mfd/syscon.h>
+
+#include <soc/sophgo/cv1800-sysctl.h>
+#include <dt-bindings/dma/cv1800-dma.h>
+
+#define DMAMUX_NCELLS			3
+#define MAX_DMA_MAPPING_ID		DMA_SPI_NOR1
+#define MAX_DMA_CPU_ID			DMA_CPU_C906_1
+#define MAX_DMA_CH_ID			7
+
+#define DMAMUX_INTMUX_REGISTER_LEN	4
+#define DMAMUX_NR_CH_PER_REGISTER	4
+#define DMAMUX_BIT_PER_CH		8
+#define DMAMUX_CH_MASk			GENMASK(5, 0)
+#define DMAMUX_INT_BIT_PER_CPU		10
+#define DMAMUX_CH_UPDATE_BIT		BIT(31)
+
+#define DMAMUX_CH_SET(chid, val) \
+	(((val) << ((chid) * DMAMUX_BIT_PER_CH)) | DMAMUX_CH_UPDATE_BIT)
+#define DMAMUX_CH_MASK(chid) \
+	DMAMUX_CH_SET(chid, DMAMUX_CH_MASk)
+
+#define DMAMUX_INT_BIT(chid, cpuid) \
+	BIT((cpuid) * DMAMUX_INT_BIT_PER_CPU + (chid))
+#define DMAMUX_INTEN_BIT(cpuid) \
+	DMAMUX_INT_BIT(8, cpuid)
+#define DMAMUX_INT_CH_BIT(chid, cpuid) \
+	(DMAMUX_INT_BIT(chid, cpuid) | DMAMUX_INTEN_BIT(cpuid))
+#define DMAMUX_INT_MASK(chid) \
+	(DMAMUX_INT_BIT(chid, DMA_CPU_A53) | \
+	 DMAMUX_INT_BIT(chid, DMA_CPU_C906_0) | \
+	 DMAMUX_INT_BIT(chid, DMA_CPU_C906_1))
+#define DMAMUX_INT_CH_MASK(chid, cpuid) \
+	(DMAMUX_INT_MASK(chid) | DMAMUX_INTEN_BIT(cpuid))
+
+struct cv1800_dmamux_data {
+	struct dma_router	dmarouter;
+	struct regmap		*regmap;
+	spinlock_t		lock;
+	DECLARE_BITMAP(used_chans, MAX_DMA_CH_ID);
+	DECLARE_BITMAP(mapped_peripherals, MAX_DMA_MAPPING_ID);
+};
+
+struct cv1800_dmamux_map {
+	unsigned int channel;
+	unsigned int peripheral;
+	unsigned int cpu;
+};
+
+static void cv1800_dmamux_free(struct device *dev, void *route_data)
+{
+	struct cv1800_dmamux_data *dmamux = dev_get_drvdata(dev);
+	struct cv1800_dmamux_map *map = route_data;
+	u32 regoff = map->channel % DMAMUX_NR_CH_PER_REGISTER;
+	u32 regpos = map->channel / DMAMUX_NR_CH_PER_REGISTER;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dmamux->lock, flags);
+
+	regmap_update_bits(dmamux->regmap,
+			   regpos + CV1800_SDMA_DMA_CHANNEL_REMAP0,
+			   DMAMUX_CH_MASK(regoff),
+			   DMAMUX_CH_UPDATE_BIT);
+
+	regmap_update_bits(dmamux->regmap, CV1800_SDMA_DMA_INT_MUX,
+			   DMAMUX_INT_CH_MASK(map->channel, map->cpu),
+			   DMAMUX_INTEN_BIT(map->cpu));
+
+	clear_bit(map->channel, dmamux->used_chans);
+	clear_bit(map->peripheral, dmamux->mapped_peripherals);
+
+	spin_unlock_irqrestore(&dmamux->lock, flags);
+
+	kfree(map);
+}
+
+static void *cv1800_dmamux_route_allocate(struct of_phandle_args *dma_spec,
+					  struct of_dma *ofdma)
+{
+	struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
+	struct cv1800_dmamux_data *dmamux = platform_get_drvdata(pdev);
+	struct cv1800_dmamux_map *map;
+	unsigned long flags;
+	unsigned int chid, devid, cpuid;
+	u32 regoff, regpos;
+
+	if (dma_spec->args_count != DMAMUX_NCELLS) {
+		dev_err(&pdev->dev, "invalid number of dma mux args\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	chid = dma_spec->args[0];
+	devid = dma_spec->args[1];
+	cpuid = dma_spec->args[2];
+	dma_spec->args_count -= 2;
+
+	if (chid > MAX_DMA_CH_ID) {
+		dev_err(&pdev->dev, "invalid channel id: %u\n", chid);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (devid > MAX_DMA_MAPPING_ID) {
+		dev_err(&pdev->dev, "invalid device id: %u\n", devid);
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (cpuid > MAX_DMA_CPU_ID) {
+		dev_err(&pdev->dev, "invalid cpu id: %u\n", cpuid);
+		return ERR_PTR(-EINVAL);
+	}
+
+	dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
+	if (!dma_spec->np) {
+		dev_err(&pdev->dev, "can't get dma master\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	map = kzalloc(sizeof(*map), GFP_KERNEL);
+	if (!map)
+		return ERR_PTR(-ENOMEM);
+
+	map->channel = chid;
+	map->peripheral = devid;
+	map->cpu = cpuid;
+
+	regoff = chid % DMAMUX_NR_CH_PER_REGISTER;
+	regpos = chid / DMAMUX_NR_CH_PER_REGISTER;
+
+	spin_lock_irqsave(&dmamux->lock, flags);
+
+	if (test_and_set_bit(devid, dmamux->mapped_peripherals)) {
+		dev_err(&pdev->dev, "already used device mapping: %u\n", devid);
+		goto failed;
+	}
+
+	if (test_and_set_bit(chid, dmamux->used_chans)) {
+		clear_bit(devid, dmamux->mapped_peripherals);
+		dev_err(&pdev->dev, "already used channel id: %u\n", chid);
+		goto failed;
+	}
+
+	regmap_set_bits(dmamux->regmap,
+			regpos + CV1800_SDMA_DMA_CHANNEL_REMAP0,
+			DMAMUX_CH_SET(regoff, devid));
+
+	regmap_update_bits(dmamux->regmap, CV1800_SDMA_DMA_INT_MUX,
+			   DMAMUX_INT_CH_MASK(chid, cpuid),
+			   DMAMUX_INT_CH_BIT(chid, cpuid));
+
+	spin_unlock_irqrestore(&dmamux->lock, flags);
+
+	dev_info(&pdev->dev, "register channel %u for req %u (cpu %u)\n",
+		 chid, devid, cpuid);
+
+	return map;
+
+failed:
+	spin_unlock_irqrestore(&dmamux->lock, flags);
+	dev_err(&pdev->dev, "already used channel id: %u\n", chid);
+	return ERR_PTR(-EBUSY);
+}
+
+static int cv1800_dmamux_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *mux_node = dev->of_node;
+	struct cv1800_dmamux_data *data;
+	struct device *parent = dev->parent;
+	struct device_node *dma_master;
+	struct regmap *map = NULL;
+
+	if (!parent)
+		return -ENODEV;
+
+	map = device_node_to_regmap(parent->of_node);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	dma_master = of_parse_phandle(mux_node, "dma-masters", 0);
+	if (!dma_master) {
+		dev_err(dev, "invalid dma-requests property\n");
+		return -ENODEV;
+	}
+	of_node_put(dma_master);
+
+	data = devm_kmalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	spin_lock_init(&data->lock);
+	data->regmap = map;
+	data->dmarouter.dev = dev;
+	data->dmarouter.route_free = cv1800_dmamux_free;
+
+	platform_set_drvdata(pdev, data);
+
+	return of_dma_router_register(mux_node,
+				      cv1800_dmamux_route_allocate,
+				      &data->dmarouter);
+}
+
+static const struct of_device_id cv1800_dmamux_ids[] = {
+	{ .compatible = "sophgo,cv1800-dmamux", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, cv1800_dmamux_ids);
+
+static struct platform_driver cv1800_dmamux_driver = {
+	.driver = {
+		.name = "fsl-raideng",
+		.of_match_table = cv1800_dmamux_ids,
+	},
+	.probe = cv1800_dmamux_probe,
+};
+module_platform_driver(cv1800_dmamux_driver);
+
+MODULE_AUTHOR("Inochi Amaoto <inochiama@outlook.com>");
+MODULE_DESCRIPTION("Sophgo CV1800/SG2000 Series Soc DMAMUX driver");
+MODULE_LICENSE("GPL");
--
2.44.0