/* * * Copyright (C) STMicroelectronics SA 2017 * Author(s): M'boumba Cedric Madianga <cedric.madianga@gmail.com> * Pierre-Yves Mordret <pierre-yves.mordret@st.com> * * License terms: GPL V2.0. * * 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. * * 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. * * 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/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; struct reset_control *rst; 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 */ unsigned long *dma_inuse; /* Used DMA channel */ u32 dma_reqs[]; /* Number of DMA Request per DMA masters. * [0] holds number of DMA Masters. * To be kept at very end 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); if (!IS_ERR(dmamux->clk)) clk_disable(dmamux->clk); 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); if (!IS_ERR(dmamux->clk)) { ret = clk_enable(dmamux->clk); if (ret < 0) { spin_unlock_irqrestore(&dmamux->lock, flags); dev_err(&pdev->dev, "clk_prep_enable issue: %d\n", ret); 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]; 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[] = { { .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; int i, count, ret; u32 dma_req; if (!node) return -ENODEV; count = device_property_read_u32_array(&pdev->dev, "dma-masters", NULL, 0); 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; stm32_dmamux->dma_inuse = devm_kcalloc(&pdev->dev, BITS_TO_LONGS(dma_req), sizeof(unsigned long), GFP_KERNEL); if (!stm32_dmamux->dma_inuse) return -ENOMEM; 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); } 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)) { ret = PTR_ERR(stm32_dmamux->clk); if (ret == -EPROBE_DEFER) dev_info(&pdev->dev, "Missing controller clock\n"); return ret; } stm32_dmamux->rst = devm_reset_control_get(&pdev->dev, NULL); if (!IS_ERR(stm32_dmamux->rst)) { reset_control_assert(stm32_dmamux->rst); udelay(2); reset_control_deassert(stm32_dmamux->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); if (!IS_ERR(stm32_dmamux->clk)) { ret = clk_prepare_enable(stm32_dmamux->clk); if (ret < 0) { dev_err(&pdev->dev, "clk_prep_enable error: %d\n", ret); return ret; } } /* Reset the dmamux */ for (i = 0; i < stm32_dmamux->dma_requests; i++) stm32_dmamux_write(stm32_dmamux->iomem, STM32_DMAMUX_CCR(i), 0); if (!IS_ERR(stm32_dmamux->clk)) clk_disable(stm32_dmamux->clk); return of_dma_router_register(node, stm32_dmamux_route_allocate, &stm32_dmamux->dmarouter); } 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, }, }; 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");