1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * DMA Router driver for LPC18xx/43xx DMA MUX 4 * 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.com 9 * 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 0x11c 24 #define LPC18XX_DMAMUX_VAL(v, n) ((v) << (n * 2)) 25 #define LPC18XX_DMAMUX_MASK(n) (0x3 << (n * 2)) 26 #define LPC18XX_DMAMUX_MAX_VAL 0x3 27 28 struct lpc18xx_dmamux { 29 u32 value; 30 bool busy; 31 }; 32 33 struct 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 42 static 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 53 static 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 } 111 112 static 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 } 163 164 static const struct of_device_id lpc18xx_dmamux_match[] = { 165 { .compatible = "nxp,lpc1850-dmamux" }, 166 {}, 167 }; 168 169 static 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 }; 176 177 static int __init lpc18xx_dmamux_init(void) 178 { 179 return platform_driver_register(&lpc18xx_dmamux_driver); 180 } 181 arch_initcall(lpc18xx_dmamux_init); 182