drivers/dma/ti-dma-crossbar.c

   1 /*
   2  *  Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
   3  *  Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  */
  10 #include <linux/slab.h>
  11 #include <linux/err.h>
  12 #include <linux/init.h>
  13 #include <linux/list.h>
  14 #include <linux/io.h>
  15 #include <linux/idr.h>
  16 #include <linux/of_address.h>
  17 #include <linux/of_device.h>
  18 #include <linux/of_dma.h>
  19
  20 #define TI_XBAR_OUTPUTS 127
  21 #define TI_XBAR_INPUTS  256
  22
  23 static DEFINE_IDR(map_idr);
  24
  25 struct ti_dma_xbar_data {
  26         void __iomem *iomem;
  27
  28         struct dma_router dmarouter;
  29
  30         u16 safe_val; /* Value to rest the crossbar lines */
  31         u32 xbar_requests; /* number of DMA requests connected to XBAR */
  32         u32 dma_requests; /* number of DMA requests forwarded to DMA */
  33 };
  34
  35 struct ti_dma_xbar_map {
  36         u16 xbar_in;
  37         int xbar_out;
  38 };
  39
  40 static inline void ti_dma_xbar_write(void __iomem *iomem, int xbar, u16 val)
  41 {
  42         writew_relaxed(val, iomem + (xbar * 2));
  43 }
  44
  45 static void ti_dma_xbar_free(struct device *dev, void *route_data)
  46 {
  47         struct ti_dma_xbar_data *xbar = dev_get_drvdata(dev);
  48         struct ti_dma_xbar_map *map = route_data;
  49
  50         dev_dbg(dev, "Unmapping XBAR%u (was routed to %d)\n",
  51                 map->xbar_in, map->xbar_out);
  52
  53         ti_dma_xbar_write(xbar->iomem, map->xbar_out, xbar->safe_val);
  54         idr_remove(&map_idr, map->xbar_out);
  55         kfree(map);
  56 }
  57
  58 static void *ti_dma_xbar_route_allocate(struct of_phandle_args *dma_spec,
  59                                         struct of_dma *ofdma)
  60 {
  61         struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
  62         struct ti_dma_xbar_data *xbar = platform_get_drvdata(pdev);
  63         struct ti_dma_xbar_map *map;
  64
  65         if (dma_spec->args[0] >= xbar->xbar_requests) {
  66                 dev_err(&pdev->dev, "Invalid XBAR request number: %d\n",
  67                         dma_spec->args[0]);
  68                 return ERR_PTR(-EINVAL);
  69         }
  70
  71         /* The of_node_put() will be done in the core for the node */
  72         dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
  73         if (!dma_spec->np) {
  74                 dev_err(&pdev->dev, "Can't get DMA master\n");
  75                 return ERR_PTR(-EINVAL);
  76         }
  77
  78         map = kzalloc(sizeof(*map), GFP_KERNEL);
  79         if (!map) {
  80                 of_node_put(dma_spec->np);
  81                 return ERR_PTR(-ENOMEM);
  82         }
  83
  84         map->xbar_out = idr_alloc(&map_idr, NULL, 0, xbar->dma_requests,
  85                                   GFP_KERNEL);
  86         map->xbar_in = (u16)dma_spec->args[0];
  87
  88         /* The DMA request is 1 based in sDMA */
  89         dma_spec->args[0] = map->xbar_out + 1;
  90
  91         dev_dbg(&pdev->dev, "Mapping XBAR%u to DMA%d\n",
  92                 map->xbar_in, map->xbar_out);
  93
  94         ti_dma_xbar_write(xbar->iomem, map->xbar_out, map->xbar_in);
  95
  96         return map;
  97 }
  98
  99 static int ti_dma_xbar_probe(struct platform_device *pdev)
 100 {
 101         struct device_node *node = pdev->dev.of_node;
 102         struct device_node *dma_node;
 103         struct ti_dma_xbar_data *xbar;
 104         struct resource *res;
 105         u32 safe_val;
 106         void __iomem *iomem;
 107         int i, ret;
 108
 109         if (!node)
 110                 return -ENODEV;
 111
 112         xbar = devm_kzalloc(&pdev->dev, sizeof(*xbar), GFP_KERNEL);
 113         if (!xbar)
 114                 return -ENOMEM;
 115
 116         dma_node = of_parse_phandle(node, "dma-masters", 0);
 117         if (!dma_node) {
 118                 dev_err(&pdev->dev, "Can't get DMA master node\n");
 119                 return -ENODEV;
 120         }
 121
 122         if (of_property_read_u32(dma_node, "dma-requests",
 123                                  &xbar->dma_requests)) {
 124                 dev_info(&pdev->dev,
 125                          "Missing XBAR output information, using %u.\n",
 126                          TI_XBAR_OUTPUTS);
 127                 xbar->dma_requests = TI_XBAR_OUTPUTS;
 128         }
 129         of_node_put(dma_node);
 130
 131         if (of_property_read_u32(node, "dma-requests", &xbar->xbar_requests)) {
 132                 dev_info(&pdev->dev,
 133                          "Missing XBAR input information, using %u.\n",
 134                          TI_XBAR_INPUTS);
 135                 xbar->xbar_requests = TI_XBAR_INPUTS;
 136         }
 137
 138         if (!of_property_read_u32(node, "ti,dma-safe-map", &safe_val))
 139                 xbar->safe_val = (u16)safe_val;
 140
 141         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 142         if (!res)
 143                 return -ENODEV;
 144
 145         iomem = devm_ioremap_resource(&pdev->dev, res);
 146         if (!iomem)
 147                 return -ENOMEM;
 148
 149         xbar->iomem = iomem;
 150
 151         xbar->dmarouter.dev = &pdev->dev;
 152         xbar->dmarouter.route_free = ti_dma_xbar_free;
 153
 154         platform_set_drvdata(pdev, xbar);
 155
 156         /* Reset the crossbar */
 157         for (i = 0; i < xbar->dma_requests; i++)
 158                 ti_dma_xbar_write(xbar->iomem, i, xbar->safe_val);
 159
 160         ret = of_dma_router_register(node, ti_dma_xbar_route_allocate,
 161                                      &xbar->dmarouter);
 162         if (ret) {
 163                 /* Restore the defaults for the crossbar */
 164                 for (i = 0; i < xbar->dma_requests; i++)
 165                         ti_dma_xbar_write(xbar->iomem, i, i);
 166         }
 167
 168         return ret;
 169 }
 170
 171 static const struct of_device_id ti_dma_xbar_match[] = {
 172         { .compatible = "ti,dra7-dma-crossbar" },
 173         {},
 174 };
 175
 176 static struct platform_driver ti_dma_xbar_driver = {
 177         .driver = {
 178                 .name = "ti-dma-crossbar",
 179                 .of_match_table = of_match_ptr(ti_dma_xbar_match),
 180         },
 181         .probe  = ti_dma_xbar_probe,
 182 };
 183
 184 int omap_dmaxbar_init(void)
 185 {
 186         return platform_driver_register(&ti_dma_xbar_driver);
 187 }
 188 arch_initcall(omap_dmaxbar_init);