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Diffstat (limited to 'drivers/dma/stm32-dmamux.c')
-rw-r--r--drivers/dma/stm32-dmamux.c402
1 files changed, 402 insertions, 0 deletions
diff --git a/drivers/dma/stm32-dmamux.c b/drivers/dma/stm32-dmamux.c
new file mode 100644
index 0000000000..8d77e2a793
--- /dev/null
+++ b/drivers/dma/stm32-dmamux.c
@@ -0,0 +1,402 @@
+// 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.h>
+#include <linux/of_dma.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.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;
+ 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);
+
+ iomem = devm_platform_ioremap_resource(pdev, 0);
+ 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>");