drivers/soc/lantiq/fpi-bus.c

   1 /*
   2  *  This program is free software; you can redistribute it and/or modify it
   3  *  under the terms of the GNU General Public License version 2 as published
   4  *  by the Free Software Foundation.
   5  *
   6  *  Copyright (C) 2011-2015 John Crispin <blogic@phrozen.org>
   7  *  Copyright (C) 2015 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
   8  *  Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de>
   9  */
  10
  11 #include <linux/device.h>
  12 #include <linux/err.h>
  13 #include <linux/mfd/syscon.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/of_platform.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/property.h>
  19 #include <linux/regmap.h>
  20
  21 #include <lantiq_soc.h>
  22
  23 #define XBAR_ALWAYS_LAST        0x430
  24 #define XBAR_FPI_BURST_EN       BIT(1)
  25 #define XBAR_AHB_BURST_EN       BIT(2)
  26
  27 #define RCU_VR9_BE_AHB1S        0x00000008
  28
  29 static int ltq_fpi_probe(struct platform_device *pdev)
  30 {
  31         struct device *dev = &pdev->dev;
  32         struct device_node *np = dev->of_node;
  33         struct resource *res_xbar;
  34         struct regmap *rcu_regmap;
  35         void __iomem *xbar_membase;
  36         u32 rcu_ahb_endianness_reg_offset;
  37         int ret;
  38
  39         res_xbar = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  40         xbar_membase = devm_ioremap_resource(dev, res_xbar);
  41         if (IS_ERR(xbar_membase))
  42                 return PTR_ERR(xbar_membase);
  43
  44         /* RCU configuration is optional */
  45         rcu_regmap = syscon_regmap_lookup_by_phandle(np, "lantiq,rcu");
  46         if (IS_ERR(rcu_regmap))
  47                 return PTR_ERR(rcu_regmap);
  48
  49         ret = device_property_read_u32(dev, "lantiq,offset-endianness",
  50                                        &rcu_ahb_endianness_reg_offset);
  51         if (ret) {
  52                 dev_err(&pdev->dev, "Failed to get RCU reg offset\n");
  53                 return ret;
  54         }
  55
  56         ret = regmap_update_bits(rcu_regmap, rcu_ahb_endianness_reg_offset,
  57                                  RCU_VR9_BE_AHB1S, RCU_VR9_BE_AHB1S);
  58         if (ret) {
  59                 dev_warn(&pdev->dev,
  60                          "Failed to configure RCU AHB endianness\n");
  61                 return ret;
  62         }
  63
  64         /* disable fpi burst */
  65         ltq_w32_mask(XBAR_FPI_BURST_EN, 0, xbar_membase + XBAR_ALWAYS_LAST);
  66
  67         return of_platform_populate(dev->of_node, NULL, NULL, dev);
  68 }
  69
  70 static const struct of_device_id ltq_fpi_match[] = {
  71         { .compatible = "lantiq,xrx200-fpi" },
  72         {},
  73 };
  74 MODULE_DEVICE_TABLE(of, ltq_fpi_match);
  75
  76 static struct platform_driver ltq_fpi_driver = {
  77         .probe = ltq_fpi_probe,
  78         .driver = {
  79                 .name = "fpi-xway",
  80                 .of_match_table = ltq_fpi_match,
  81         },
  82 };
  83
  84 module_platform_driver(ltq_fpi_driver);
  85
  86 MODULE_DESCRIPTION("Lantiq FPI bus driver");
  87 MODULE_LICENSE("GPL");