1 /* 2 * DMA Router driver for LPC18xx/43xx DMA MUX 3 * 4 * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com> 5 * 6 * Based on TI DMA Crossbar driver by: 7 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com 8 * Author: Peter Ujfalusi <peter.ujfalusi@ti.com> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 * 14 */ 15 16 #include <linux/err.h> 17 #include <linux/init.h> 18 #include <linux/mfd/syscon.h> 19 #include <linux/of_device.h> 20 #include <linux/of_dma.h> 21 #include <linux/regmap.h> 22 #include <linux/spinlock.h> 23 24 /* CREG register offset and macros for mux manipulation */ 25 #define LPC18XX_CREG_DMAMUX 0x11c 26 #define LPC18XX_DMAMUX_VAL(v, n) ((v) << (n * 2)) 27 #define LPC18XX_DMAMUX_MASK(n) (0x3 << (n * 2)) 28 #define LPC18XX_DMAMUX_MAX_VAL 0x3 29 30 struct lpc18xx_dmamux { 31 u32 value; 32 bool busy; 33 }; 34 35 struct lpc18xx_dmamux_data { 36 struct dma_router dmarouter; 37 struct lpc18xx_dmamux *muxes; 38 u32 dma_master_requests; 39 u32 dma_mux_requests; 40 struct regmap *reg; 41 spinlock_t lock; 42 }; 43 44 static void lpc18xx_dmamux_free(struct device *dev, void *route_data) 45 { 46 struct lpc18xx_dmamux_data *dmamux = dev_get_drvdata(dev); 47 struct lpc18xx_dmamux *mux = route_data; 48 unsigned long flags; 49 50 spin_lock_irqsave(&dmamux->lock, flags); 51 mux->busy = false; 52 spin_unlock_irqrestore(&dmamux->lock, flags); 53 } 54 55 static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec, 56 struct of_dma *ofdma) 57 { 58 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node); 59 struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev); 60 unsigned long flags; 61 unsigned mux; 62 63 if (dma_spec->args_count != 3) { 64 dev_err(&pdev->dev, "invalid number of dma mux args\n"); 65 return ERR_PTR(-EINVAL); 66 } 67 68 mux = dma_spec->args[0]; 69 if (mux >= dmamux->dma_master_requests) { 70 dev_err(&pdev->dev, "invalid mux number: %d\n", 71 dma_spec->args[0]); 72 return ERR_PTR(-EINVAL); 73 } 74 75 if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) { 76 dev_err(&pdev->dev, "invalid dma mux value: %d\n", 77 dma_spec->args[1]); 78 return ERR_PTR(-EINVAL); 79 } 80 81 /* The of_node_put() will be done in the core for the node */ 82 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0); 83 if (!dma_spec->np) { 84 dev_err(&pdev->dev, "can't get dma master\n"); 85 return ERR_PTR(-EINVAL); 86 } 87 88 spin_lock_irqsave(&dmamux->lock, flags); 89 if (dmamux->muxes[mux].busy) { 90 spin_unlock_irqrestore(&dmamux->lock, flags); 91 dev_err(&pdev->dev, "dma request %u busy with %u.%u\n", 92 mux, mux, dmamux->muxes[mux].value); 93 of_node_put(dma_spec->np); 94 return ERR_PTR(-EBUSY); 95 } 96 97 dmamux->muxes[mux].busy = true; 98 dmamux->muxes[mux].value = dma_spec->args[1]; 99 100 regmap_update_bits(dmamux->reg, LPC18XX_CREG_DMAMUX, 101 LPC18XX_DMAMUX_MASK(mux), 102 LPC18XX_DMAMUX_VAL(dmamux->muxes[mux].value, mux)); 103 spin_unlock_irqrestore(&dmamux->lock, flags); 104 105 dma_spec->args[1] = dma_spec->args[2]; 106 dma_spec->args_count = 2; 107 108 dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux, 109 dmamux->muxes[mux].value, mux); 110 111 return &dmamux->muxes[mux]; 112 } 113 114 static int lpc18xx_dmamux_probe(struct platform_device *pdev) 115 { 116 struct device_node *dma_np, *np = pdev->dev.of_node; 117 struct lpc18xx_dmamux_data *dmamux; 118 int ret; 119 120 dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL); 121 if (!dmamux) 122 return -ENOMEM; 123 124 dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg"); 125 if (IS_ERR(dmamux->reg)) { 126 dev_err(&pdev->dev, "syscon lookup failed\n"); 127 return PTR_ERR(dmamux->reg); 128 } 129 130 ret = of_property_read_u32(np, "dma-requests", 131 &dmamux->dma_mux_requests); 132 if (ret) { 133 dev_err(&pdev->dev, "missing dma-requests property\n"); 134 return ret; 135 } 136 137 dma_np = of_parse_phandle(np, "dma-masters", 0); 138 if (!dma_np) { 139 dev_err(&pdev->dev, "can't get dma master\n"); 140 return -ENODEV; 141 } 142 143 ret = of_property_read_u32(dma_np, "dma-requests", 144 &dmamux->dma_master_requests); 145 of_node_put(dma_np); 146 if (ret) { 147 dev_err(&pdev->dev, "missing master dma-requests property\n"); 148 return ret; 149 } 150 151 dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests, 152 sizeof(struct lpc18xx_dmamux), 153 GFP_KERNEL); 154 if (!dmamux->muxes) 155 return -ENOMEM; 156 157 spin_lock_init(&dmamux->lock); 158 platform_set_drvdata(pdev, dmamux); 159 dmamux->dmarouter.dev = &pdev->dev; 160 dmamux->dmarouter.route_free = lpc18xx_dmamux_free; 161 162 return of_dma_router_register(np, lpc18xx_dmamux_reserve, 163 &dmamux->dmarouter); 164 } 165 166 static const struct of_device_id lpc18xx_dmamux_match[] = { 167 { .compatible = "nxp,lpc1850-dmamux" }, 168 {}, 169 }; 170 171 static struct platform_driver lpc18xx_dmamux_driver = { 172 .probe = lpc18xx_dmamux_probe, 173 .driver = { 174 .name = "lpc18xx-dmamux", 175 .of_match_table = lpc18xx_dmamux_match, 176 }, 177 }; 178 179 static int __init lpc18xx_dmamux_init(void) 180 { 181 return platform_driver_register(&lpc18xx_dmamux_driver); 182 } 183 arch_initcall(lpc18xx_dmamux_init); 184