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_device.h> 16 #include <linux/of_dma.h> 17 #include <linux/regmap.h> 18 #include <linux/spinlock.h> 19 20 /* CREG register offset and macros for mux manipulation */ 21 #define LPC18XX_CREG_DMAMUX 0x11c 22 #define LPC18XX_DMAMUX_VAL(v, n) ((v) << (n * 2)) 23 #define LPC18XX_DMAMUX_MASK(n) (0x3 << (n * 2)) 24 #define LPC18XX_DMAMUX_MAX_VAL 0x3 25 26 struct lpc18xx_dmamux { 27 u32 value; 28 bool busy; 29 }; 30 31 struct lpc18xx_dmamux_data { 32 struct dma_router dmarouter; 33 struct lpc18xx_dmamux *muxes; 34 u32 dma_master_requests; 35 u32 dma_mux_requests; 36 struct regmap *reg; 37 spinlock_t lock; 38 }; 39 40 static void lpc18xx_dmamux_free(struct device *dev, void *route_data) 41 { 42 struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev); 43 struct lpc18xx_dmamux *mux = route_data; 44 unsigned long flags; 45 46 spin_lock_irqsave(&dmamux->lock, flags); 47 mux->busy = false; 48 spin_unlock_irqrestore(&dmamux->lock, flags); 49 } 50 51 static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec, 52 struct of_dma *ofdma) 53 { 54 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node); 55 struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev); 56 unsigned long flags; 57 unsigned mux; 58 59 if (dma_spec->args_count != 3) { 60 dev_err(&pdev->dev, "invalid number of dma mux args\n"); 61 return ERR_PTR(-EINVAL); 62 } 63 64 mux = dma_spec->args[0]; 65 if (mux >= dmamux->dma_master_requests) { 66 dev_err(&pdev->dev, "invalid mux number: %d\n", 67 dma_spec->args[0]); 68 return ERR_PTR(-EINVAL); 69 } 70 71 if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) { 72 dev_err(&pdev->dev, "invalid dma mux value: %d\n", 73 dma_spec->args[1]); 74 return ERR_PTR(-EINVAL); 75 } 76 77 /* The of_node_put() will be done in the core for the node */ 78 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0); 79 if (!dma_spec->np) { 80 dev_err(&pdev->dev, "can't get dma master\n"); 81 return ERR_PTR(-EINVAL); 82 } 83 84 spin_lock_irqsave(&dmamux->lock, flags); 85 if (dmamux->muxes[mux].busy) { 86 spin_unlock_irqrestore(&dmamux->lock, flags); 87 dev_err(&pdev->dev, "dma request %u busy with %u.%u\n", 88 mux, mux, dmamux->muxes[mux].value); 89 of_node_put(dma_spec->np); 90 return ERR_PTR(-EBUSY); 91 } 92 93 dmamux->muxes[mux].busy = true; 94 dmamux->muxes[mux].value = dma_spec->args[1]; 95 96 regmap_update_bits(dmamux->reg, LPC18XX_CREG_DMAMUX, 97 LPC18XX_DMAMUX_MASK(mux), 98 LPC18XX_DMAMUX_VAL(dmamux->muxes[mux].value, mux)); 99 spin_unlock_irqrestore(&dmamux->lock, flags); 100 101 dma_spec->args[1] = dma_spec->args[2]; 102 dma_spec->args_count = 2; 103 104 dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux, 105 dmamux->muxes[mux].value, mux); 106 107 return &dmamux->muxes[mux]; 108 } 109 110 static int lpc18xx_dmamux_probe(struct platform_device *pdev) 111 { 112 struct device_node *dma_np, *np = pdev->dev.of_node; 113 struct lpc18xx_dmamux_data *dmamux; 114 int ret; 115 116 dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL); 117 if (!dmamux) 118 return -ENOMEM; 119 120 dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg"); 121 if (IS_ERR(dmamux->reg)) { 122 dev_err(&pdev->dev, "syscon lookup failed\n"); 123 return PTR_ERR(dmamux->reg); 124 } 125 126 ret = of_property_read_u32(np, "dma-requests", 127 &dmamux->dma_mux_requests); 128 if (ret) { 129 dev_err(&pdev->dev, "missing dma-requests property\n"); 130 return ret; 131 } 132 133 dma_np = of_parse_phandle(np, "dma-masters", 0); 134 if (!dma_np) { 135 dev_err(&pdev->dev, "can't get dma master\n"); 136 return -ENODEV; 137 } 138 139 ret = of_property_read_u32(dma_np, "dma-requests", 140 &dmamux->dma_master_requests); 141 of_node_put(dma_np); 142 if (ret) { 143 dev_err(&pdev->dev, "missing master dma-requests property\n"); 144 return ret; 145 } 146 147 dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests, 148 sizeof(struct lpc18xx_dmamux), 149 GFP_KERNEL); 150 if (!dmamux->muxes) 151 return -ENOMEM; 152 153 spin_lock_init(&dmamux->lock); 154 platform_set_drvdata(pdev, dmamux); 155 dmamux->dmarouter.dev = &pdev->dev; 156 dmamux->dmarouter.route_free = lpc18xx_dmamux_free; 157 158 return of_dma_router_register(np, lpc18xx_dmamux_reserve, 159 &dmamux->dmarouter); 160 } 161 162 static const struct of_device_id lpc18xx_dmamux_match[] = { 163 { .compatible = "nxp,lpc1850-dmamux" }, 164 {}, 165 }; 166 167 static struct platform_driver lpc18xx_dmamux_driver = { 168 .probe = lpc18xx_dmamux_probe, 169 .driver = { 170 .name = "lpc18xx-dmamux", 171 .of_match_table = lpc18xx_dmamux_match, 172 }, 173 }; 174 175 static int __init lpc18xx_dmamux_init(void) 176 { 177 return platform_driver_register(&lpc18xx_dmamux_driver); 178 } 179 arch_initcall(lpc18xx_dmamux_init); 180