drivers/dma/lpc32xx-dmamux.c

   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 i;
  99
 100         if (dma_spec->args_count != 3) {
 101                 dev_err(&pdev->dev, "invalid number of dma mux args\n");
 102                 return ERR_PTR(-EINVAL);
 103         }
 104
 105         for (i = 0; i < ARRAY_SIZE(lpc32xx_muxes); i++) {
 106                 if (lpc32xx_muxes[i].signal == dma_spec->args[0]) {
 107                         mux = &lpc32xx_muxes[i];
 108                         break;
 109                 }
 110         }
 111         if (!mux) {
 112                 dev_err(&pdev->dev, "invalid mux request number: %d\n",
 113                         dma_spec->args[0]);
 114                 return ERR_PTR(-EINVAL);
 115         }
 116
 117         if (dma_spec->args[2] > 1) {
 118                 dev_err(&pdev->dev, "invalid dma mux value: %d\n",
 119                         dma_spec->args[1]);
 120                 return ERR_PTR(-EINVAL);
 121         }
 122
 123         /* The of_node_put() will be done in the core for the node */
 124         dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
 125         if (!dma_spec->np) {
 126                 dev_err(&pdev->dev, "can't get dma master\n");
 127                 return ERR_PTR(-EINVAL);
 128         }
 129
 130         spin_lock_irqsave(&dmamux->lock, flags);
 131         if (mux->busy) {
 132                 spin_unlock_irqrestore(&dmamux->lock, flags);
 133                 dev_err(dev, "dma request signal %d busy, routed to %s\n",
 134                         mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
 135                 of_node_put(dma_spec->np);
 136                 return ERR_PTR(-EBUSY);
 137         }
 138
 139         mux->busy = true;
 140         mux->muxval = dma_spec->args[2] ? BIT(mux->bit) : 0;
 141
 142         regmap_update_bits(dmamux->reg, mux->muxreg, BIT(mux->bit), mux->muxval);
 143         spin_unlock_irqrestore(&dmamux->lock, flags);
 144
 145         dma_spec->args[2] = 0;
 146         dma_spec->args_count = 2;
 147
 148         dev_dbg(dev, "dma request signal %d routed to %s\n",
 149                 mux->signal, mux->muxval ? mux->name_sel1 : mux->name_sel1);
 150
 151         return mux;
 152 }
 153
 154 static int lpc32xx_dmamux_probe(struct platform_device *pdev)
 155 {
 156         struct device_node *np = pdev->dev.of_node;
 157         struct lpc32xx_dmamux_data *dmamux;
 158
 159         dmamux = devm_kzalloc(&pdev->dev, sizeof(*dmamux), GFP_KERNEL);
 160         if (!dmamux)
 161                 return -ENOMEM;
 162
 163         dmamux->reg = syscon_node_to_regmap(np->parent);
 164         if (IS_ERR(dmamux->reg)) {
 165                 dev_err(&pdev->dev, "syscon lookup failed\n");
 166                 return PTR_ERR(dmamux->reg);
 167         }
 168
 169         spin_lock_init(&dmamux->lock);
 170         platform_set_drvdata(pdev, dmamux);
 171         dmamux->dmarouter.dev = &pdev->dev;
 172         dmamux->dmarouter.route_free = lpc32xx_dmamux_release;
 173
 174         return of_dma_router_register(np, lpc32xx_dmamux_reserve,
 175                                       &dmamux->dmarouter);
 176 }
 177
 178 static const struct of_device_id lpc32xx_dmamux_match[] = {
 179         { .compatible = "nxp,lpc3220-dmamux" },
 180         {},
 181 };
 182
 183 static struct platform_driver lpc32xx_dmamux_driver = {
 184         .probe  = lpc32xx_dmamux_probe,
 185         .driver = {
 186                 .name = "lpc32xx-dmamux",
 187                 .of_match_table = lpc32xx_dmamux_match,
 188         },
 189 };
 190
 191 static int __init lpc32xx_dmamux_init(void)
 192 {
 193         return platform_driver_register(&lpc32xx_dmamux_driver);
 194 }
 195 arch_initcall(lpc32xx_dmamux_init);