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       1                 :            : /*
       2                 :            :  * OF helpers for IOMMU
       3                 :            :  *
       4                 :            :  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
       5                 :            :  *
       6                 :            :  * This program is free software; you can redistribute it and/or modify it
       7                 :            :  * under the terms and conditions of the GNU General Public License,
       8                 :            :  * version 2, as published by the Free Software Foundation.
       9                 :            :  *
      10                 :            :  * This program is distributed in the hope it will be useful, but WITHOUT
      11                 :            :  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
      12                 :            :  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
      13                 :            :  * more details.
      14                 :            :  *
      15                 :            :  * You should have received a copy of the GNU General Public License along with
      16                 :            :  * this program; if not, write to the Free Software Foundation, Inc.,
      17                 :            :  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
      18                 :            :  */
      19                 :            : 
      20                 :            : #include <linux/export.h>
      21                 :            : #include <linux/limits.h>
      22                 :            : #include <linux/of.h>
      23                 :            : #include <linux/of_iommu.h>
      24                 :            : 
      25                 :            : /**
      26                 :            :  * of_get_dma_window - Parse *dma-window property and returns 0 if found.
      27                 :            :  *
      28                 :            :  * @dn: device node
      29                 :            :  * @prefix: prefix for property name if any
      30                 :            :  * @index: index to start to parse
      31                 :            :  * @busno: Returns busno if supported. Otherwise pass NULL
      32                 :            :  * @addr: Returns address that DMA starts
      33                 :            :  * @size: Returns the range that DMA can handle
      34                 :            :  *
      35                 :            :  * This supports different formats flexibly. "prefix" can be
      36                 :            :  * configured if any. "busno" and "index" are optionally
      37                 :            :  * specified. Set 0(or NULL) if not used.
      38                 :            :  */
      39                 :          0 : int of_get_dma_window(struct device_node *dn, const char *prefix, int index,
      40                 :            :                       unsigned long *busno, dma_addr_t *addr, size_t *size)
      41                 :            : {
      42                 :            :         const __be32 *dma_window, *end;
      43                 :            :         int bytes, cur_index = 0;
      44                 :            :         char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX];
      45                 :            : 
      46 [ #  # ][ #  # ]:          0 :         if (!dn || !addr || !size)
      47                 :            :                 return -EINVAL;
      48                 :            : 
      49         [ #  # ]:          0 :         if (!prefix)
      50                 :            :                 prefix = "";
      51                 :            : 
      52                 :          0 :         snprintf(propname, sizeof(propname), "%sdma-window", prefix);
      53                 :          0 :         snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix);
      54                 :          0 :         snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix);
      55                 :            : 
      56                 :          0 :         dma_window = of_get_property(dn, propname, &bytes);
      57         [ #  # ]:          0 :         if (!dma_window)
      58                 :            :                 return -ENODEV;
      59                 :          0 :         end = dma_window + bytes / sizeof(*dma_window);
      60                 :            : 
      61         [ #  # ]:          0 :         while (dma_window < end) {
      62                 :            :                 u32 cells;
      63                 :          0 :                 const void *prop;
      64                 :            : 
      65                 :            :                 /* busno is one cell if supported */
      66         [ #  # ]:          0 :                 if (busno)
      67                 :          0 :                         *busno = be32_to_cpup(dma_window++);
      68                 :            : 
      69                 :          0 :                 prop = of_get_property(dn, addrname, NULL);
      70         [ #  # ]:          0 :                 if (!prop)
      71                 :          0 :                         prop = of_get_property(dn, "#address-cells", NULL);
      72                 :            : 
      73         [ #  # ]:          0 :                 cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn);
      74         [ #  # ]:          0 :                 if (!cells)
      75                 :            :                         return -EINVAL;
      76                 :          0 :                 *addr = of_read_number(dma_window, cells);
      77                 :          0 :                 dma_window += cells;
      78                 :            : 
      79                 :          0 :                 prop = of_get_property(dn, sizename, NULL);
      80         [ #  # ]:          0 :                 cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn);
      81         [ #  # ]:          0 :                 if (!cells)
      82                 :            :                         return -EINVAL;
      83                 :          0 :                 *size = of_read_number(dma_window, cells);
      84                 :          0 :                 dma_window += cells;
      85                 :            : 
      86         [ #  # ]:          0 :                 if (cur_index++ == index)
      87                 :            :                         break;
      88                 :            :         }
      89                 :            :         return 0;
      90                 :            : }
      91                 :            : EXPORT_SYMBOL_GPL(of_get_dma_window);