182 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * DMA Router driver for LPC18xx/43xx DMA MUX4 *5 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>6 *7 * Based on TI DMA Crossbar driver by:8 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com9 * Author: Peter Ujfalusi <peter.ujfalusi@ti.com>10 */11 12#include <linux/err.h>13#include <linux/init.h>14#include <linux/mfd/syscon.h>15#include <linux/of.h>16#include <linux/of_dma.h>17#include <linux/of_platform.h>18#include <linux/platform_device.h>19#include <linux/regmap.h>20#include <linux/spinlock.h>21 22/* CREG register offset and macros for mux manipulation */23#define LPC18XX_CREG_DMAMUX 0x11c24#define LPC18XX_DMAMUX_VAL(v, n) ((v) << (n * 2))25#define LPC18XX_DMAMUX_MASK(n) (0x3 << (n * 2))26#define LPC18XX_DMAMUX_MAX_VAL 0x327 28struct lpc18xx_dmamux {29 u32 value;30 bool busy;31};32 33struct lpc18xx_dmamux_data {34 struct dma_router dmarouter;35 struct lpc18xx_dmamux *muxes;36 u32 dma_master_requests;37 u32 dma_mux_requests;38 struct regmap *reg;39 spinlock_t lock;40};41 42static void lpc18xx_dmamux_free(struct device *dev, void *route_data)43{44 struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev);45 struct lpc18xx_dmamux *mux = route_data;46 unsigned long flags;47 48 spin_lock_irqsave(&dmamux->lock, flags);49 mux->busy = false;50 spin_unlock_irqrestore(&dmamux->lock, flags);51}52 53static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec,54 struct of_dma *ofdma)55{56 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);57 struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev);58 unsigned long flags;59 unsigned mux;60 61 if (dma_spec->args_count != 3) {62 dev_err(&pdev->dev, "invalid number of dma mux args\n");63 return ERR_PTR(-EINVAL);64 }65 66 mux = dma_spec->args[0];67 if (mux >= dmamux->dma_master_requests) {68 dev_err(&pdev->dev, "invalid mux number: %d\n",69 dma_spec->args[0]);70 return ERR_PTR(-EINVAL);71 }72 73 if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) {74 dev_err(&pdev->dev, "invalid dma mux value: %d\n",75 dma_spec->args[1]);76 return ERR_PTR(-EINVAL);77 }78 79 /* The of_node_put() will be done in the core for the node */80 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);81 if (!dma_spec->np) {82 dev_err(&pdev->dev, "can't get dma master\n");83 return ERR_PTR(-EINVAL);84 }85 86 spin_lock_irqsave(&dmamux->lock, flags);87 if (dmamux->muxes[mux].busy) {88 spin_unlock_irqrestore(&dmamux->lock, flags);89 dev_err(&pdev->dev, "dma request %u busy with %u.%u\n",90 mux, mux, dmamux->muxes[mux].value);91 of_node_put(dma_spec->np);92 return ERR_PTR(-EBUSY);93 }94 95 dmamux->muxes[mux].busy = true;96 dmamux->muxes[mux].value = dma_spec->args[1];97 98 regmap_update_bits(dmamux->reg, LPC18XX_CREG_DMAMUX,99 LPC18XX_DMAMUX_MASK(mux),100 LPC18XX_DMAMUX_VAL(dmamux->muxes[mux].value, mux));101 spin_unlock_irqrestore(&dmamux->lock, flags);102 103 dma_spec->args[1] = dma_spec->args[2];104 dma_spec->args_count = 2;105 106 dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux,107 dmamux->muxes[mux].value, mux);108 109 return &dmamux->muxes[mux];110}111 112static int lpc18xx_dmamux_probe(struct platform_device *pdev)113{114 struct device_node *dma_np, *np = pdev->dev.of_node;115 struct lpc18xx_dmamux_data *dmamux;116 int ret;117 118 dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);119 if (!dmamux)120 return -ENOMEM;121 122 dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg");123 if (IS_ERR(dmamux->reg)) {124 dev_err(&pdev->dev, "syscon lookup failed\n");125 return PTR_ERR(dmamux->reg);126 }127 128 ret = of_property_read_u32(np, "dma-requests",129 &dmamux->dma_mux_requests);130 if (ret) {131 dev_err(&pdev->dev, "missing dma-requests property\n");132 return ret;133 }134 135 dma_np = of_parse_phandle(np, "dma-masters", 0);136 if (!dma_np) {137 dev_err(&pdev->dev, "can't get dma master\n");138 return -ENODEV;139 }140 141 ret = of_property_read_u32(dma_np, "dma-requests",142 &dmamux->dma_master_requests);143 of_node_put(dma_np);144 if (ret) {145 dev_err(&pdev->dev, "missing master dma-requests property\n");146 return ret;147 }148 149 dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests,150 sizeof(struct lpc18xx_dmamux),151 GFP_KERNEL);152 if (!dmamux->muxes)153 return -ENOMEM;154 155 spin_lock_init(&dmamux->lock);156 platform_set_drvdata(pdev, dmamux);157 dmamux->dmarouter.dev = &pdev->dev;158 dmamux->dmarouter.route_free = lpc18xx_dmamux_free;159 160 return of_dma_router_register(np, lpc18xx_dmamux_reserve,161 &dmamux->dmarouter);162}163 164static const struct of_device_id lpc18xx_dmamux_match[] = {165 { .compatible = "nxp,lpc1850-dmamux" },166 {},167};168 169static struct platform_driver lpc18xx_dmamux_driver = {170 .probe = lpc18xx_dmamux_probe,171 .driver = {172 .name = "lpc18xx-dmamux",173 .of_match_table = lpc18xx_dmamux_match,174 },175};176 177static int __init lpc18xx_dmamux_init(void)178{179 return platform_driver_register(&lpc18xx_dmamux_driver);180}181arch_initcall(lpc18xx_dmamux_init);182