1 files changed, 403 insertions, 0 deletions

diff --git a/drivers/dma/stm32-dmamux.c b/drivers/dma/stm32-dmamux.c
new file mode 100644
index 000000000..ee3cbbf51
--- /dev/null
+++ b/drivers/dma/stm32-dmamux.c
@@ -0,0 +1,403 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Copyright (C) STMicroelectronics SA 2017
+ * Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com>
+ *            Pierre-Yves Mordret <pierre-yves.mordret@st.com>
+ *
+ * DMA Router driver for STM32 DMA MUX
+ *
+ * Based on TI DMA Crossbar driver
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_dma.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#define STM32_DMAMUX_CCR(x)		(0x4 * (x))
+#define STM32_DMAMUX_MAX_DMA_REQUESTS	32
+#define STM32_DMAMUX_MAX_REQUESTS	255
+
+struct stm32_dmamux {
+	u32 master;
+	u32 request;
+	u32 chan_id;
+};
+
+struct stm32_dmamux_data {
+	struct dma_router dmarouter;
+	struct clk *clk;
+	void __iomem *iomem;
+	u32 dma_requests; /* Number of DMA requests connected to DMAMUX */
+	u32 dmamux_requests; /* Number of DMA requests routed toward DMAs */
+	spinlock_t lock; /* Protects register access */
+	DECLARE_BITMAP(dma_inuse, STM32_DMAMUX_MAX_DMA_REQUESTS); /* Used DMA channel */
+	u32 ccr[STM32_DMAMUX_MAX_DMA_REQUESTS]; /* Used to backup CCR register
+						 * in suspend
+						 */
+	u32 dma_reqs[]; /* Number of DMA Request per DMA masters.
+			 *  [0] holds number of DMA Masters.
+			 *  To be kept at very end of this structure
+			 */
+};
+
+static inline u32 stm32_dmamux_read(void __iomem *iomem, u32 reg)
+{
+	return readl_relaxed(iomem + reg);
+}
+
+static inline void stm32_dmamux_write(void __iomem *iomem, u32 reg, u32 val)
+{
+	writel_relaxed(val, iomem + reg);
+}
+
+static void stm32_dmamux_free(struct device *dev, void *route_data)
+{
+	struct stm32_dmamux_data *dmamux = dev_get_drvdata(dev);
+	struct stm32_dmamux *mux = route_data;
+	unsigned long flags;
+
+	/* Clear dma request */
+	spin_lock_irqsave(&dmamux->lock, flags);
+
+	stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id), 0);
+	clear_bit(mux->chan_id, dmamux->dma_inuse);
+
+	pm_runtime_put_sync(dev);
+
+	spin_unlock_irqrestore(&dmamux->lock, flags);
+
+	dev_dbg(dev, "Unmapping DMAMUX(%u) to DMA%u(%u)\n",
+		mux->request, mux->master, mux->chan_id);
+
+	kfree(mux);
+}
+
+static void *stm32_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 stm32_dmamux_data *dmamux = platform_get_drvdata(pdev);
+	struct stm32_dmamux *mux;
+	u32 i, min, max;
+	int ret;
+	unsigned long flags;
+
+	if (dma_spec->args_count != 3) {
+		dev_err(&pdev->dev, "invalid number of dma mux args\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (dma_spec->args[0] > dmamux->dmamux_requests) {
+		dev_err(&pdev->dev, "invalid mux request number: %d\n",
+			dma_spec->args[0]);
+		return ERR_PTR(-EINVAL);
+	}
+
+	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock_irqsave(&dmamux->lock, flags);
+	mux->chan_id = find_first_zero_bit(dmamux->dma_inuse,
+					   dmamux->dma_requests);
+
+	if (mux->chan_id == dmamux->dma_requests) {
+		spin_unlock_irqrestore(&dmamux->lock, flags);
+		dev_err(&pdev->dev, "Run out of free DMA requests\n");
+		ret = -ENOMEM;
+		goto error_chan_id;
+	}
+	set_bit(mux->chan_id, dmamux->dma_inuse);
+	spin_unlock_irqrestore(&dmamux->lock, flags);
+
+	/* Look for DMA Master */
+	for (i = 1, min = 0, max = dmamux->dma_reqs[i];
+	     i <= dmamux->dma_reqs[0];
+	     min += dmamux->dma_reqs[i], max += dmamux->dma_reqs[++i])
+		if (mux->chan_id < max)
+			break;
+	mux->master = i - 1;
+
+	/* The of_node_put() will be done in of_dma_router_xlate function */
+	dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1);
+	if (!dma_spec->np) {
+		dev_err(&pdev->dev, "can't get dma master\n");
+		ret = -EINVAL;
+		goto error;
+	}
+
+	/* Set dma request */
+	spin_lock_irqsave(&dmamux->lock, flags);
+	ret = pm_runtime_resume_and_get(&pdev->dev);
+	if (ret < 0) {
+		spin_unlock_irqrestore(&dmamux->lock, flags);
+		goto error;
+	}
+	spin_unlock_irqrestore(&dmamux->lock, flags);
+
+	mux->request = dma_spec->args[0];
+
+	/*  craft DMA spec */
+	dma_spec->args[3] = dma_spec->args[2] | mux->chan_id << 16;
+	dma_spec->args[2] = dma_spec->args[1];
+	dma_spec->args[1] = 0;
+	dma_spec->args[0] = mux->chan_id - min;
+	dma_spec->args_count = 4;
+
+	stm32_dmamux_write(dmamux->iomem, STM32_DMAMUX_CCR(mux->chan_id),
+			   mux->request);
+	dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n",
+		mux->request, mux->master, mux->chan_id);
+
+	return mux;
+
+error:
+	clear_bit(mux->chan_id, dmamux->dma_inuse);
+
+error_chan_id:
+	kfree(mux);
+	return ERR_PTR(ret);
+}
+
+static const struct of_device_id stm32_stm32dma_master_match[] __maybe_unused = {
+	{ .compatible = "st,stm32-dma", },
+	{},
+};
+
+static int stm32_dmamux_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	const struct of_device_id *match;
+	struct device_node *dma_node;
+	struct stm32_dmamux_data *stm32_dmamux;
+	struct resource *res;
+	void __iomem *iomem;
+	struct reset_control *rst;
+	int i, count, ret;
+	u32 dma_req;
+
+	if (!node)
+		return -ENODEV;
+
+	count = device_property_count_u32(&pdev->dev, "dma-masters");
+	if (count < 0) {
+		dev_err(&pdev->dev, "Can't get DMA master(s) node\n");
+		return -ENODEV;
+	}
+
+	stm32_dmamux = devm_kzalloc(&pdev->dev, sizeof(*stm32_dmamux) +
+				    sizeof(u32) * (count + 1), GFP_KERNEL);
+	if (!stm32_dmamux)
+		return -ENOMEM;
+
+	dma_req = 0;
+	for (i = 1; i <= count; i++) {
+		dma_node = of_parse_phandle(node, "dma-masters", i - 1);
+
+		match = of_match_node(stm32_stm32dma_master_match, dma_node);
+		if (!match) {
+			dev_err(&pdev->dev, "DMA master is not supported\n");
+			of_node_put(dma_node);
+			return -EINVAL;
+		}
+
+		if (of_property_read_u32(dma_node, "dma-requests",
+					 &stm32_dmamux->dma_reqs[i])) {
+			dev_info(&pdev->dev,
+				 "Missing MUX output information, using %u.\n",
+				 STM32_DMAMUX_MAX_DMA_REQUESTS);
+			stm32_dmamux->dma_reqs[i] =
+				STM32_DMAMUX_MAX_DMA_REQUESTS;
+		}
+		dma_req += stm32_dmamux->dma_reqs[i];
+		of_node_put(dma_node);
+	}
+
+	if (dma_req > STM32_DMAMUX_MAX_DMA_REQUESTS) {
+		dev_err(&pdev->dev, "Too many DMA Master Requests to manage\n");
+		return -ENODEV;
+	}
+
+	stm32_dmamux->dma_requests = dma_req;
+	stm32_dmamux->dma_reqs[0] = count;
+
+	if (device_property_read_u32(&pdev->dev, "dma-requests",
+				     &stm32_dmamux->dmamux_requests)) {
+		stm32_dmamux->dmamux_requests = STM32_DMAMUX_MAX_REQUESTS;
+		dev_warn(&pdev->dev, "DMAMUX defaulting on %u requests\n",
+			 stm32_dmamux->dmamux_requests);
+	}
+	pm_runtime_get_noresume(&pdev->dev);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	iomem = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(iomem))
+		return PTR_ERR(iomem);
+
+	spin_lock_init(&stm32_dmamux->lock);
+
+	stm32_dmamux->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(stm32_dmamux->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(stm32_dmamux->clk),
+				     "Missing clock controller\n");
+
+	ret = clk_prepare_enable(stm32_dmamux->clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret);
+		return ret;
+	}
+
+	rst = devm_reset_control_get(&pdev->dev, NULL);
+	if (IS_ERR(rst)) {
+		ret = PTR_ERR(rst);
+		if (ret == -EPROBE_DEFER)
+			goto err_clk;
+	} else if (count > 1) { /* Don't reset if there is only one dma-master */
+		reset_control_assert(rst);
+		udelay(2);
+		reset_control_deassert(rst);
+	}
+
+	stm32_dmamux->iomem = iomem;
+	stm32_dmamux->dmarouter.dev = &pdev->dev;
+	stm32_dmamux->dmarouter.route_free = stm32_dmamux_free;
+
+	platform_set_drvdata(pdev, stm32_dmamux);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	pm_runtime_get_noresume(&pdev->dev);
+
+	/* Reset the dmamux */
+	for (i = 0; i < stm32_dmamux->dma_requests; i++)
+		stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0);
+
+	pm_runtime_put(&pdev->dev);
+
+	ret = of_dma_router_register(node, stm32_dmamux_route_allocate,
+				     &stm32_dmamux->dmarouter);
+	if (ret)
+		goto pm_disable;
+
+	return 0;
+
+pm_disable:
+	pm_runtime_disable(&pdev->dev);
+err_clk:
+	clk_disable_unprepare(stm32_dmamux->clk);
+
+	return ret;
+}
+
+#ifdef CONFIG_PM
+static int stm32_dmamux_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(stm32_dmamux->clk);
+
+	return 0;
+}
+
+static int stm32_dmamux_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = clk_prepare_enable(stm32_dmamux->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to prepare_enable clock\n");
+		return ret;
+	}
+
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_PM_SLEEP
+static int stm32_dmamux_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
+	int i, ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < stm32_dmamux->dma_requests; i++)
+		stm32_dmamux->ccr[i] = stm32_dmamux_read(stm32_dmamux->iomem,
+							 STM32_DMAMUX_CCR(i));
+
+	pm_runtime_put_sync(dev);
+
+	pm_runtime_force_suspend(dev);
+
+	return 0;
+}
+
+static int stm32_dmamux_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct stm32_dmamux_data *stm32_dmamux = platform_get_drvdata(pdev);
+	int i, ret;
+
+	ret = pm_runtime_force_resume(dev);
+	if (ret < 0)
+		return ret;
+
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < stm32_dmamux->dma_requests; i++)
+		stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i),
+				   stm32_dmamux->ccr[i]);
+
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops stm32_dmamux_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(stm32_dmamux_suspend, stm32_dmamux_resume)
+	SET_RUNTIME_PM_OPS(stm32_dmamux_runtime_suspend,
+			   stm32_dmamux_runtime_resume, NULL)
+};
+
+static const struct of_device_id stm32_dmamux_match[] = {
+	{ .compatible = "st,stm32h7-dmamux" },
+	{},
+};
+
+static struct platform_driver stm32_dmamux_driver = {
+	.probe	= stm32_dmamux_probe,
+	.driver = {
+		.name = "stm32-dmamux",
+		.of_match_table = stm32_dmamux_match,
+		.pm = &stm32_dmamux_pm_ops,
+	},
+};
+
+static int __init stm32_dmamux_init(void)
+{
+	return platform_driver_register(&stm32_dmamux_driver);
+}
+arch_initcall(stm32_dmamux_init);
+
+MODULE_DESCRIPTION("DMA Router driver for STM32 DMA MUX");
+MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
+MODULE_AUTHOR("Pierre-Yves Mordret <pierre-yves.mordret@st.com>");
+MODULE_LICENSE("GPL v2");