drivers/bus/uniphier-system-bus.c

   1 /*
   2  * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/io.h>
  16 #include <linux/log2.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/of_address.h>
  20 #include <linux/of_platform.h>
  21 #include <linux/platform_device.h>
  22
  23 /* System Bus Controller registers */
  24 #define UNIPHIER_SBC_BASE       0x100   /* base address of bank0 space */
  25 #define    UNIPHIER_SBC_BASE_BE         BIT(0)  /* bank_enable */
  26 #define UNIPHIER_SBC_CTRL0      0x200   /* timing parameter 0 of bank0 */
  27 #define UNIPHIER_SBC_CTRL1      0x204   /* timing parameter 1 of bank0 */
  28 #define UNIPHIER_SBC_CTRL2      0x208   /* timing parameter 2 of bank0 */
  29 #define UNIPHIER_SBC_CTRL3      0x20c   /* timing parameter 3 of bank0 */
  30 #define UNIPHIER_SBC_CTRL4      0x300   /* timing parameter 4 of bank0 */
  31
  32 #define UNIPHIER_SBC_STRIDE     0x10    /* register stride to next bank */
  33 #define UNIPHIER_SBC_NR_BANKS   8       /* number of banks (chip select) */
  34 #define UNIPHIER_SBC_BASE_DUMMY 0xffffffff      /* data to squash bank 0, 1 */
  35
  36 struct uniphier_system_bus_bank {
  37         u32 base;
  38         u32 end;
  39 };
  40
  41 struct uniphier_system_bus_priv {
  42         struct device *dev;
  43         void __iomem *membase;
  44         struct uniphier_system_bus_bank bank[UNIPHIER_SBC_NR_BANKS];
  45 };
  46
  47 static int uniphier_system_bus_add_bank(struct uniphier_system_bus_priv *priv,
  48                                         int bank, u32 addr, u64 paddr, u32 size)
  49 {
  50         u64 end, mask;
  51
  52         dev_dbg(priv->dev,
  53                 "range found: bank = %d, addr = %08x, paddr = %08llx, size = %08x\n",
  54                 bank, addr, paddr, size);
  55
  56         if (bank >= ARRAY_SIZE(priv->bank)) {
  57                 dev_err(priv->dev, "unsupported bank number %d\n", bank);
  58                 return -EINVAL;
  59         }
  60
  61         if (priv->bank[bank].base || priv->bank[bank].end) {
  62                 dev_err(priv->dev,
  63                         "range for bank %d has already been specified\n", bank);
  64                 return -EINVAL;
  65         }
  66
  67         if (paddr > U32_MAX) {
  68                 dev_err(priv->dev, "base address %llx is too high\n", paddr);
  69                 return -EINVAL;
  70         }
  71
  72         end = paddr + size;
  73
  74         if (addr > paddr) {
  75                 dev_err(priv->dev,
  76                         "base %08x cannot be mapped to %08llx of parent\n",
  77                         addr, paddr);
  78                 return -EINVAL;
  79         }
  80         paddr -= addr;
  81
  82         paddr = round_down(paddr, 0x00020000);
  83         end = round_up(end, 0x00020000);
  84
  85         if (end > U32_MAX) {
  86                 dev_err(priv->dev, "end address %08llx is too high\n", end);
  87                 return -EINVAL;
  88         }
  89         mask = paddr ^ (end - 1);
  90         mask = roundup_pow_of_two(mask);
  91
  92         paddr = round_down(paddr, mask);
  93         end = round_up(end, mask);
  94
  95         priv->bank[bank].base = paddr;
  96         priv->bank[bank].end = end;
  97
  98         dev_dbg(priv->dev, "range added: bank = %d, addr = %08x, end = %08x\n",
  99                 bank, priv->bank[bank].base, priv->bank[bank].end);
 100
 101         return 0;
 102 }
 103
 104 static int uniphier_system_bus_check_overlap(
 105                                 const struct uniphier_system_bus_priv *priv)
 106 {
 107         int i, j;
 108
 109         for (i = 0; i < ARRAY_SIZE(priv->bank); i++) {
 110                 for (j = i + 1; j < ARRAY_SIZE(priv->bank); j++) {
 111                         if (priv->bank[i].end > priv->bank[j].base &&
 112                             priv->bank[i].base < priv->bank[j].end) {
 113                                 dev_err(priv->dev,
 114                                         "region overlap between bank%d and bank%d\n",
 115                                         i, j);
 116                                 return -EINVAL;
 117                         }
 118                 }
 119         }
 120
 121         return 0;
 122 }
 123
 124 static void uniphier_system_bus_check_boot_swap(
 125                                         struct uniphier_system_bus_priv *priv)
 126 {
 127         void __iomem *base_reg = priv->membase + UNIPHIER_SBC_BASE;
 128         int is_swapped;
 129
 130         is_swapped = !(readl(base_reg) & UNIPHIER_SBC_BASE_BE);
 131
 132         dev_dbg(priv->dev, "Boot Swap: %s\n", is_swapped ? "on" : "off");
 133
 134         /*
 135          * If BOOT_SWAP was asserted on power-on-reset, the CS0 and CS1 are
 136          * swapped.  In this case, bank0 and bank1 should be swapped as well.
 137          */
 138         if (is_swapped)
 139                 swap(priv->bank[0], priv->bank[1]);
 140 }
 141
 142 static void uniphier_system_bus_set_reg(
 143                                 const struct uniphier_system_bus_priv *priv)
 144 {
 145         void __iomem *base_reg = priv->membase + UNIPHIER_SBC_BASE;
 146         u32 base, end, mask, val;
 147         int i;
 148
 149         for (i = 0; i < ARRAY_SIZE(priv->bank); i++) {
 150                 base = priv->bank[i].base;
 151                 end = priv->bank[i].end;
 152
 153                 if (base == end) {
 154                         /*
 155                          * If SBC_BASE0 or SBC_BASE1 is set to zero, the access
 156                          * to anywhere in the system bus space is routed to
 157                          * bank 0 (if boot swap if off) or bank 1 (if boot swap
 158                          * if on).  It means that CPUs cannot get access to
 159                          * bank 2 or later.  In other words, bank 0/1 cannot
 160                          * be disabled even if its bank_enable bits is cleared.
 161                          * This seems odd, but it is how this hardware goes.
 162                          * As a workaround, dummy data (0xffffffff) should be
 163                          * set when the bank 0/1 is unused.  As for bank 2 and
 164                          * later, they can be simply disable by clearing the
 165                          * bank_enable bit.
 166                          */
 167                         if (i < 2)
 168                                 val = UNIPHIER_SBC_BASE_DUMMY;
 169                         else
 170                                 val = 0;
 171                 } else {
 172                         mask = base ^ (end - 1);
 173
 174                         val = base & 0xfffe0000;
 175                         val |= (~mask >> 16) & 0xfffe;
 176                         val |= UNIPHIER_SBC_BASE_BE;
 177                 }
 178                 dev_dbg(priv->dev, "SBC_BASE[%d] = 0x%08x\n", i, val);
 179
 180                 writel(val, base_reg + UNIPHIER_SBC_STRIDE * i);
 181         }
 182 }
 183
 184 static int uniphier_system_bus_probe(struct platform_device *pdev)
 185 {
 186         struct device *dev = &pdev->dev;
 187         struct uniphier_system_bus_priv *priv;
 188         struct resource *regs;
 189         const __be32 *ranges;
 190         u32 cells, addr, size;
 191         u64 paddr;
 192         int pna, bank, rlen, rone, ret;
 193
 194         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 195         if (!priv)
 196                 return -ENOMEM;
 197
 198         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 199         priv->membase = devm_ioremap_resource(dev, regs);
 200         if (IS_ERR(priv->membase))
 201                 return PTR_ERR(priv->membase);
 202
 203         priv->dev = dev;
 204
 205         pna = of_n_addr_cells(dev->of_node);
 206
 207         ret = of_property_read_u32(dev->of_node, "#address-cells", &cells);
 208         if (ret) {
 209                 dev_err(dev, "failed to get #address-cells\n");
 210                 return ret;
 211         }
 212         if (cells != 2) {
 213                 dev_err(dev, "#address-cells must be 2\n");
 214                 return -EINVAL;
 215         }
 216
 217         ret = of_property_read_u32(dev->of_node, "#size-cells", &cells);
 218         if (ret) {
 219                 dev_err(dev, "failed to get #size-cells\n");
 220                 return ret;
 221         }
 222         if (cells != 1) {
 223                 dev_err(dev, "#size-cells must be 1\n");
 224                 return -EINVAL;
 225         }
 226
 227         ranges = of_get_property(dev->of_node, "ranges", &rlen);
 228         if (!ranges) {
 229                 dev_err(dev, "failed to get ranges property\n");
 230                 return -ENOENT;
 231         }
 232
 233         rlen /= sizeof(*ranges);
 234         rone = pna + 2;
 235
 236         for (; rlen >= rone; rlen -= rone) {
 237                 bank = be32_to_cpup(ranges++);
 238                 addr = be32_to_cpup(ranges++);
 239                 paddr = of_translate_address(dev->of_node, ranges);
 240                 if (paddr == OF_BAD_ADDR)
 241                         return -EINVAL;
 242                 ranges += pna;
 243                 size = be32_to_cpup(ranges++);
 244
 245                 ret = uniphier_system_bus_add_bank(priv, bank, addr,
 246                                                    paddr, size);
 247                 if (ret)
 248                         return ret;
 249         }
 250
 251         ret = uniphier_system_bus_check_overlap(priv);
 252         if (ret)
 253                 return ret;
 254
 255         uniphier_system_bus_check_boot_swap(priv);
 256
 257         uniphier_system_bus_set_reg(priv);
 258
 259         /* Now, the bus is configured.  Populate platform_devices below it */
 260         return of_platform_default_populate(dev->of_node, NULL, dev);
 261 }
 262
 263 static const struct of_device_id uniphier_system_bus_match[] = {
 264         { .compatible = "socionext,uniphier-system-bus" },
 265         { /* sentinel */ }
 266 };
 267 MODULE_DEVICE_TABLE(of, uniphier_system_bus_match);
 268
 269 static struct platform_driver uniphier_system_bus_driver = {
 270         .probe          = uniphier_system_bus_probe,
 271         .driver = {
 272                 .name   = "uniphier-system-bus",
 273                 .of_match_table = uniphier_system_bus_match,
 274         },
 275 };
 276 module_platform_driver(uniphier_system_bus_driver);
 277
 278 MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
 279 MODULE_DESCRIPTION("UniPhier System Bus driver");
 280 MODULE_LICENSE("GPL");