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