1 // SPDX-License-Identifier: GPL-2.0-only 2 // 3 // Copyright 2024 Timesys Corporation <piotr.wojtaszczyk@timesys.com> 4 // 5 // Based on TI DMA Crossbar driver by: 6 // Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com 7 // Author: Peter Ujfalusi <peter.ujfalusi@ti.com> 8 9 #include <linux/err.h> 10 #include <linux/init.h> 11 #include <linux/mfd/syscon.h> 12 #include <linux/of.h> 13 #include <linux/of_dma.h> 14 #include <linux/of_platform.h> 15 #include <linux/platform_device.h> 16 #include <linux/regmap.h> 17 #include <linux/spinlock.h> 18 19 #define LPC32XX_SSP_CLK_CTRL 0x78 20 #define LPC32XX_I2S_CLK_CTRL 0x7c 21 22 struct lpc32xx_dmamux { 23 int signal; 24 char *name_sel0; 25 char *name_sel1; 26 int muxval; 27 int muxreg; 28 int bit; 29 bool busy; 30 }; 31 32 struct lpc32xx_dmamux_data { 33 struct dma_router dmarouter; 34 struct regmap *reg; 35 spinlock_t lock; /* protects busy status flag */ 36 }; 37 38 /* From LPC32x0 User manual "3.2.1 DMA request signals" */ 39 static struct lpc32xx_dmamux lpc32xx_muxes[] = { 40 { 41 .signal = 3, 42 .name_sel0 = "spi2-rx-tx", 43 .name_sel1 = "ssp1-rx", 44 .muxreg = LPC32XX_SSP_CLK_CTRL, 45 .bit = 5, 46 }, 47 { 48 .signal = 10, 49 .name_sel0 = "uart7-rx", 50 .name_sel1 = "i2s1-dma1", 51 .muxreg = LPC32XX_I2S_CLK_CTRL, 52 .bit = 4, 53 }, 54 { 55 .signal = 11, 56 .name_sel0 = "spi1-rx-tx", 57 .name_sel1 = "ssp1-tx", 58 .muxreg = LPC32XX_SSP_CLK_CTRL, 59 .bit = 4, 60 }, 61 { 62 .signal = 14, 63 .name_sel0 = "none", 64 .name_sel1 = "ssp0-rx", 65 .muxreg = LPC32XX_SSP_CLK_CTRL, 66 .bit = 3, 67 }, 68 { 69 .signal = 15, 70 .name_sel0 = "none", 71 .name_sel1 = "ssp0-tx", 72 .muxreg = LPC32XX_SSP_CLK_CTRL, 73 .bit = 2, 74 }, 75 }; 76 77 static void lpc32xx_dmamux_release(struct device *dev, void *route_data) 78 { 79 struct lpc32xx_dmamux_data *dmamux = dev_get_drvdata(dev); 80 struct lpc32xx_dmamux *mux = route_data; 81 82 dev_dbg(dev, "releasing dma request signal %d routed to %s\n", 83 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1); 84 85 guard(spinlock)(&dmamux->lock); 86 87 mux->busy = false; 88 } 89 90 static void *lpc32xx_dmamux_reserve(struct of_phandle_args *dma_spec, 91 struct of_dma *ofdma) 92 { 93 struct platform_device *pdev = of_find_device_by_node(ofdma->of_node); 94 struct device *dev = &pdev->dev; 95 struct lpc32xx_dmamux_data *dmamux = platform_get_drvdata(pdev); 96 unsigned long flags; 97 struct lpc32xx_dmamux *mux = NULL; 98 int ret = -EINVAL; 99 int i; 100 101 if (dma_spec->args_count != 3) { 102 dev_err(&pdev->dev, "invalid number of dma mux args\n"); 103 goto err_put_pdev; 104 } 105 106 for (i = 0; i < ARRAY_SIZE(lpc32xx_muxes); i++) { 107 if (lpc32xx_muxes[i].signal == dma_spec->args[0]) { 108 mux = &lpc32xx_muxes[i]; 109 break; 110 } 111 } 112 if (!mux) { 113 dev_err(&pdev->dev, "invalid mux request number: %d\n", 114 dma_spec->args[0]); 115 goto err_put_pdev; 116 } 117 118 if (dma_spec->args[2] > 1) { 119 dev_err(&pdev->dev, "invalid dma mux value: %d\n", 120 dma_spec->args[1]); 121 goto err_put_pdev; 122 } 123 124 /* The of_node_put() will be done in the core for the node */ 125 dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0); 126 if (!dma_spec->np) { 127 dev_err(&pdev->dev, "can't get dma master\n"); 128 goto err_put_pdev; 129 } 130 131 spin_lock_irqsave(&dmamux->lock, flags); 132 if (mux->busy) { 133 spin_unlock_irqrestore(&dmamux->lock, flags); 134 dev_err(dev, "dma request signal %d busy, routed to %s\n", 135 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1); 136 of_node_put(dma_spec->np); 137 ret = -EBUSY; 138 goto err_put_pdev; 139 } 140 141 mux->busy = true; 142 mux->muxval = dma_spec->args[2] ? BIT(mux->bit) : 0; 143 144 regmap_update_bits(dmamux->reg, mux->muxreg, BIT(mux->bit), mux->muxval); 145 spin_unlock_irqrestore(&dmamux->lock, flags); 146 147 dma_spec->args[2] = 0; 148 dma_spec->args_count = 2; 149 150 dev_dbg(dev, "dma request signal %d routed to %s\n", 151 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1); 152 153 put_device(&pdev->dev); 154 155 return mux; 156 157 err_put_pdev: 158 put_device(&pdev->dev); 159 160 return ERR_PTR(ret); 161 } 162 163 static int lpc32xx_dmamux_probe(struct platform_device *pdev) 164 { 165 struct device_node *np = pdev->dev.of_node; 166 struct lpc32xx_dmamux_data *dmamux; 167 168 dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL); 169 if (!dmamux) 170 return -ENOMEM; 171 172 dmamux->reg = syscon_node_to_regmap(np->parent); 173 if (IS_ERR(dmamux->reg)) { 174 dev_err(&pdev->dev, "syscon lookup failed\n"); 175 return PTR_ERR(dmamux->reg); 176 } 177 178 spin_lock_init(&dmamux->lock); 179 platform_set_drvdata(pdev, dmamux); 180 dmamux->dmarouter.dev = &pdev->dev; 181 dmamux->dmarouter.route_free = lpc32xx_dmamux_release; 182 183 return of_dma_router_register(np, lpc32xx_dmamux_reserve, 184 &dmamux->dmarouter); 185 } 186 187 static const struct of_device_id lpc32xx_dmamux_match[] = { 188 { .compatible = "nxp,lpc3220-dmamux" }, 189 {}, 190 }; 191 192 static struct platform_driver lpc32xx_dmamux_driver = { 193 .probe = lpc32xx_dmamux_probe, 194 .driver = { 195 .name = "lpc32xx-dmamux", 196 .of_match_table = lpc32xx_dmamux_match, 197 }, 198 }; 199 200 static int __init lpc32xx_dmamux_init(void) 201 { 202 return platform_driver_register(&lpc32xx_dmamux_driver); 203 } 204 arch_initcall(lpc32xx_dmamux_init); 205