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1// SPDX-License-Identifier: GPL-2.0-only2//3// Copyright 2024 Timesys Corporation <piotr.wojtaszczyk@timesys.com>4//5// Based on TI DMA Crossbar driver by:6// Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com7// Author: Peter Ujfalusi <peter.ujfalusi@ti.com>8 9#include <linux/err.h>10#include <linux/init.h>11#include <linux/mfd/syscon.h>12#include <linux/of.h>13#include <linux/of_dma.h>14#include <linux/of_platform.h>15#include <linux/platform_device.h>16#include <linux/regmap.h>17#include <linux/spinlock.h>18 19#define LPC32XX_SSP_CLK_CTRL 0x7820#define LPC32XX_I2S_CLK_CTRL 0x7c21 22struct lpc32xx_dmamux {23 int signal;24 char *name_sel0;25 char *name_sel1;26 int muxval;27 int muxreg;28 int bit;29 bool busy;30};31 32struct lpc32xx_dmamux_data {33 struct dma_router dmarouter;34 struct regmap *reg;35 spinlock_t lock; /* protects busy status flag */36};37 38/* From LPC32x0 User manual "3.2.1 DMA request signals" */39static struct lpc32xx_dmamux lpc32xx_muxes[] = {40 {41 .signal = 3,42 .name_sel0 = "spi2-rx-tx",43 .name_sel1 = "ssp1-rx",44 .muxreg = LPC32XX_SSP_CLK_CTRL,45 .bit = 5,46 },47 {48 .signal = 10,49 .name_sel0 = "uart7-rx",50 .name_sel1 = "i2s1-dma1",51 .muxreg = LPC32XX_I2S_CLK_CTRL,52 .bit = 4,53 },54 {55 .signal = 11,56 .name_sel0 = "spi1-rx-tx",57 .name_sel1 = "ssp1-tx",58 .muxreg = LPC32XX_SSP_CLK_CTRL,59 .bit = 4,60 },61 {62 .signal = 14,63 .name_sel0 = "none",64 .name_sel1 = "ssp0-rx",65 .muxreg = LPC32XX_SSP_CLK_CTRL,66 .bit = 3,67 },68 {69 .signal = 15,70 .name_sel0 = "none",71 .name_sel1 = "ssp0-tx",72 .muxreg = LPC32XX_SSP_CLK_CTRL,73 .bit = 2,74 },75};76 77static void lpc32xx_dmamux_release(struct device *dev, void *route_data)78{79 struct lpc32xx_dmamux_data *dmamux = dev_get_drvdata(dev);80 struct lpc32xx_dmamux *mux = route_data;81 82 dev_dbg(dev, "releasing dma request signal %d routed to %s\n",83 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);84 85 guard(spinlock)(&dmamux->lock);86 87 mux->busy = false;88}89 90static void *lpc32xx_dmamux_reserve(struct of_phandle_args *dma_spec,91 struct of_dma *ofdma)92{93 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);94 struct device *dev = &pdev->dev;95 struct lpc32xx_dmamux_data *dmamux = platform_get_drvdata(pdev);96 unsigned long flags;97 struct lpc32xx_dmamux *mux = NULL;98 int i;99 100 if (dma_spec->args_count != 3) {101 dev_err(&pdev->dev, "invalid number of dma mux args\n");102 return ERR_PTR(-EINVAL);103 }104 105 for (i = 0; i < ARRAY_SIZE(lpc32xx_muxes); i++) {106 if (lpc32xx_muxes[i].signal == dma_spec->args[0]) {107 mux = &lpc32xx_muxes[i];108 break;109 }110 }111 if (!mux) {112 dev_err(&pdev->dev, "invalid mux request number: %d\n",113 dma_spec->args[0]);114 return ERR_PTR(-EINVAL);115 }116 117 if (dma_spec->args[2] > 1) {118 dev_err(&pdev->dev, "invalid dma mux value: %d\n",119 dma_spec->args[1]);120 return ERR_PTR(-EINVAL);121 }122 123 /* The of_node_put() will be done in the core for the node */124 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);125 if (!dma_spec->np) {126 dev_err(&pdev->dev, "can't get dma master\n");127 return ERR_PTR(-EINVAL);128 }129 130 spin_lock_irqsave(&dmamux->lock, flags);131 if (mux->busy) {132 spin_unlock_irqrestore(&dmamux->lock, flags);133 dev_err(dev, "dma request signal %d busy, routed to %s\n",134 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);135 of_node_put(dma_spec->np);136 return ERR_PTR(-EBUSY);137 }138 139 mux->busy = true;140 mux->muxval = dma_spec->args[2] ? BIT(mux->bit) : 0;141 142 regmap_update_bits(dmamux->reg, mux->muxreg, BIT(mux->bit), mux->muxval);143 spin_unlock_irqrestore(&dmamux->lock, flags);144 145 dma_spec->args[2] = 0;146 dma_spec->args_count = 2;147 148 dev_dbg(dev, "dma request signal %d routed to %s\n",149 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);150 151 return mux;152}153 154static int lpc32xx_dmamux_probe(struct platform_device *pdev)155{156 struct device_node *np = pdev->dev.of_node;157 struct lpc32xx_dmamux_data *dmamux;158 159 dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);160 if (!dmamux)161 return -ENOMEM;162 163 dmamux->reg = syscon_node_to_regmap(np->parent);164 if (IS_ERR(dmamux->reg)) {165 dev_err(&pdev->dev, "syscon lookup failed\n");166 return PTR_ERR(dmamux->reg);167 }168 169 spin_lock_init(&dmamux->lock);170 platform_set_drvdata(pdev, dmamux);171 dmamux->dmarouter.dev = &pdev->dev;172 dmamux->dmarouter.route_free = lpc32xx_dmamux_release;173 174 return of_dma_router_register(np, lpc32xx_dmamux_reserve,175 &dmamux->dmarouter);176}177 178static const struct of_device_id lpc32xx_dmamux_match[] = {179 { .compatible = "nxp,lpc3220-dmamux" },180 {},181};182 183static struct platform_driver lpc32xx_dmamux_driver = {184 .probe = lpc32xx_dmamux_probe,185 .driver = {186 .name = "lpc32xx-dmamux",187 .of_match_table = lpc32xx_dmamux_match,188 },189};190 191static int __init lpc32xx_dmamux_init(void)192{193 return platform_driver_register(&lpc32xx_dmamux_driver);194}195arch_initcall(lpc32xx_dmamux_init);196