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179 lines
4.7 KiB
179 lines
4.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* DMA Router driver for LPC18xx/43xx DMA MUX |
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* |
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* Copyright (C) 2015 Joachim Eastwood <[email protected]> |
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* |
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* Based on TI DMA Crossbar driver by: |
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* Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com |
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* Author: Peter Ujfalusi <[email protected]> |
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*/ |
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#include <linux/err.h> |
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#include <linux/init.h> |
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#include <linux/mfd/syscon.h> |
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#include <linux/of_device.h> |
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#include <linux/of_dma.h> |
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#include <linux/regmap.h> |
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#include <linux/spinlock.h> |
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/* CREG register offset and macros for mux manipulation */ |
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#define LPC18XX_CREG_DMAMUX 0x11c |
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#define LPC18XX_DMAMUX_VAL(v, n) ((v) << (n * 2)) |
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#define LPC18XX_DMAMUX_MASK(n) (0x3 << (n * 2)) |
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#define LPC18XX_DMAMUX_MAX_VAL 0x3 |
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struct lpc18xx_dmamux { |
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u32 value; |
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bool busy; |
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}; |
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struct lpc18xx_dmamux_data { |
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struct dma_router dmarouter; |
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struct lpc18xx_dmamux *muxes; |
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u32 dma_master_requests; |
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u32 dma_mux_requests; |
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struct regmap *reg; |
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spinlock_t lock; |
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}; |
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static void lpc18xx_dmamux_free(struct device *dev, void *route_data) |
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{ |
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struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev); |
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struct lpc18xx_dmamux *mux = route_data; |
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unsigned long flags; |
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spin_lock_irqsave(&dmamux->lock, flags); |
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mux->busy = false; |
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spin_unlock_irqrestore(&dmamux->lock, flags); |
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} |
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static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec, |
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struct of_dma *ofdma) |
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{ |
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struct platform_device *pdev = of_find_device_by_node(ofdma->of_node); |
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struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev); |
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unsigned long flags; |
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unsigned mux; |
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if (dma_spec->args_count != 3) { |
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dev_err(&pdev->dev, "invalid number of dma mux args\n"); |
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return ERR_PTR(-EINVAL); |
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} |
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mux = dma_spec->args[0]; |
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if (mux >= dmamux->dma_master_requests) { |
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dev_err(&pdev->dev, "invalid mux number: %d\n", |
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dma_spec->args[0]); |
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return ERR_PTR(-EINVAL); |
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} |
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if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) { |
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dev_err(&pdev->dev, "invalid dma mux value: %d\n", |
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dma_spec->args[1]); |
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return ERR_PTR(-EINVAL); |
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} |
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/* The of_node_put() will be done in the core for the node */ |
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dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0); |
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if (!dma_spec->np) { |
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dev_err(&pdev->dev, "can't get dma master\n"); |
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return ERR_PTR(-EINVAL); |
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} |
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spin_lock_irqsave(&dmamux->lock, flags); |
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if (dmamux->muxes[mux].busy) { |
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spin_unlock_irqrestore(&dmamux->lock, flags); |
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dev_err(&pdev->dev, "dma request %u busy with %u.%u\n", |
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mux, mux, dmamux->muxes[mux].value); |
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of_node_put(dma_spec->np); |
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return ERR_PTR(-EBUSY); |
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} |
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dmamux->muxes[mux].busy = true; |
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dmamux->muxes[mux].value = dma_spec->args[1]; |
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regmap_update_bits(dmamux->reg, LPC18XX_CREG_DMAMUX, |
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LPC18XX_DMAMUX_MASK(mux), |
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LPC18XX_DMAMUX_VAL(dmamux->muxes[mux].value, mux)); |
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spin_unlock_irqrestore(&dmamux->lock, flags); |
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dma_spec->args[1] = dma_spec->args[2]; |
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dma_spec->args_count = 2; |
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dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux, |
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dmamux->muxes[mux].value, mux); |
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return &dmamux->muxes[mux]; |
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} |
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static int lpc18xx_dmamux_probe(struct platform_device *pdev) |
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{ |
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struct device_node *dma_np, *np = pdev->dev.of_node; |
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struct lpc18xx_dmamux_data *dmamux; |
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int ret; |
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dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL); |
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if (!dmamux) |
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return -ENOMEM; |
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dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg"); |
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if (IS_ERR(dmamux->reg)) { |
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dev_err(&pdev->dev, "syscon lookup failed\n"); |
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return PTR_ERR(dmamux->reg); |
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} |
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ret = of_property_read_u32(np, "dma-requests", |
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&dmamux->dma_mux_requests); |
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if (ret) { |
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dev_err(&pdev->dev, "missing dma-requests property\n"); |
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return ret; |
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} |
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dma_np = of_parse_phandle(np, "dma-masters", 0); |
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if (!dma_np) { |
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dev_err(&pdev->dev, "can't get dma master\n"); |
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return -ENODEV; |
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} |
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ret = of_property_read_u32(dma_np, "dma-requests", |
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&dmamux->dma_master_requests); |
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of_node_put(dma_np); |
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if (ret) { |
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dev_err(&pdev->dev, "missing master dma-requests property\n"); |
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return ret; |
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} |
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dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests, |
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sizeof(struct lpc18xx_dmamux), |
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GFP_KERNEL); |
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if (!dmamux->muxes) |
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return -ENOMEM; |
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spin_lock_init(&dmamux->lock); |
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platform_set_drvdata(pdev, dmamux); |
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dmamux->dmarouter.dev = &pdev->dev; |
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dmamux->dmarouter.route_free = lpc18xx_dmamux_free; |
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return of_dma_router_register(np, lpc18xx_dmamux_reserve, |
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&dmamux->dmarouter); |
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} |
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static const struct of_device_id lpc18xx_dmamux_match[] = { |
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{ .compatible = "nxp,lpc1850-dmamux" }, |
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{}, |
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}; |
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static struct platform_driver lpc18xx_dmamux_driver = { |
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.probe = lpc18xx_dmamux_probe, |
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.driver = { |
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.name = "lpc18xx-dmamux", |
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.of_match_table = lpc18xx_dmamux_match, |
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}, |
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}; |
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static int __init lpc18xx_dmamux_init(void) |
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{ |
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return platform_driver_register(&lpc18xx_dmamux_driver); |
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} |
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arch_initcall(lpc18xx_dmamux_init);
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