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 int ret = -EINVAL; 61 62 if (dma_spec->args_count != 3) { 63 dev_err(&pdev->dev, "invalid number of dma mux args\n"); 64 goto err_put_pdev; 65 } 66 67 mux = dma_spec->args[0]; 68 if (mux >= dmamux->dma_master_requests) { 69 dev_err(&pdev->dev, "invalid mux number: %d\n", 70 dma_spec->args[0]); 71 goto err_put_pdev; 72 } 73 74 if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) { 75 dev_err(&pdev->dev, "invalid dma mux value: %d\n", 76 dma_spec->args[1]); 77 goto err_put_pdev; 78 } 79 80 /* The of_node_put() will be done in the core for the node */ 81 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0); 82 if (!dma_spec->np) { 83 dev_err(&pdev->dev, "can't get dma master\n"); 84 goto err_put_pdev; 85 } 86 87 spin_lock_irqsave(&dmamux->lock, flags); 88 if (dmamux->muxes[mux].busy) { 89 spin_unlock_irqrestore(&dmamux->lock, flags); 90 dev_err(&pdev->dev, "dma request %u busy with %u.%u\n", 91 mux, mux, dmamux->muxes[mux].value); 92 of_node_put(dma_spec->np); 93 ret = -EBUSY; 94 goto err_put_pdev; 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 put_device(&pdev->dev); 112 113 return &dmamux->muxes[mux]; 114 115 err_put_pdev: 116 put_device(&pdev->dev); 117 118 return ERR_PTR(ret); 119 } 120 121 static int lpc18xx_dmamux_probe(struct platform_device *pdev) 122 { 123 struct device_node *dma_np, *np = pdev->dev.of_node; 124 struct lpc18xx_dmamux_data *dmamux; 125 int ret; 126 127 dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL); 128 if (!dmamux) 129 return -ENOMEM; 130 131 dmamux->reg = syscon_regmap_lookup_by_compatible("nxp,lpc1850-creg"); 132 if (IS_ERR(dmamux->reg)) { 133 dev_err(&pdev->dev, "syscon lookup failed\n"); 134 return PTR_ERR(dmamux->reg); 135 } 136 137 ret = of_property_read_u32(np, "dma-requests", 138 &dmamux->dma_mux_requests); 139 if (ret) { 140 dev_err(&pdev->dev, "missing dma-requests property\n"); 141 return ret; 142 } 143 144 dma_np = of_parse_phandle(np, "dma-masters", 0); 145 if (!dma_np) { 146 dev_err(&pdev->dev, "can't get dma master\n"); 147 return -ENODEV; 148 } 149 150 ret = of_property_read_u32(dma_np, "dma-requests", 151 &dmamux->dma_master_requests); 152 of_node_put(dma_np); 153 if (ret) { 154 dev_err(&pdev->dev, "missing master dma-requests property\n"); 155 return ret; 156 } 157 158 dmamux->muxes = devm_kcalloc(&pdev->dev, dmamux->dma_master_requests, 159 sizeof(struct lpc18xx_dmamux), 160 GFP_KERNEL); 161 if (!dmamux->muxes) 162 return -ENOMEM; 163 164 spin_lock_init(&dmamux->lock); 165 platform_set_drvdata(pdev, dmamux); 166 dmamux->dmarouter.dev = &pdev->dev; 167 dmamux->dmarouter.route_free = lpc18xx_dmamux_free; 168 169 return of_dma_router_register(np, lpc18xx_dmamux_reserve, 170 &dmamux->dmarouter); 171 } 172 173 static const struct of_device_id lpc18xx_dmamux_match[] = { 174 { .compatible = "nxp,lpc1850-dmamux" }, 175 {}, 176 }; 177 178 static struct platform_driver lpc18xx_dmamux_driver = { 179 .probe = lpc18xx_dmamux_probe, 180 .driver = { 181 .name = "lpc18xx-dmamux", 182 .of_match_table = lpc18xx_dmamux_match, 183 }, 184 }; 185 186 static int __init lpc18xx_dmamux_init(void) 187 { 188 return platform_driver_register(&lpc18xx_dmamux_driver); 189 } 190 arch_initcall(lpc18xx_dmamux_init); 191