arch/arm/mach-at91/soc.c

   1 /*
   2  * Copyright (C) 2015 Atmel
   3  *
   4  * Alexandre Belloni <alexandre.belloni@free-electrons.com
   5  * Boris Brezillon <boris.brezillon@free-electrons.com
   6  *
   7  * This file is licensed under the terms of the GNU General Public
   8  * License version 2.  This program is licensed "as is" without any
   9  * warranty of any kind, whether express or implied.
  10  *
  11  */
  12
  13 #define pr_fmt(fmt)     "AT91: " fmt
  14
  15 #include <linux/io.h>
  16 #include <linux/of.h>
  17 #include <linux/of_address.h>
  18 #include <linux/of_platform.h>
  19 #include <linux/slab.h>
  20 #include <linux/sys_soc.h>
  21
  22 #include "soc.h"
  23
  24 #define AT91_DBGU_CIDR                  0x40
  25 #define AT91_DBGU_EXID                  0x44
  26 #define AT91_CHIPID_CIDR                0x00
  27 #define AT91_CHIPID_EXID                0x04
  28 #define AT91_CIDR_VERSION(x)            ((x) & 0x1f)
  29 #define AT91_CIDR_EXT                   BIT(31)
  30 #define AT91_CIDR_MATCH_MASK            0x7fffffe0
  31
  32 static int __init at91_get_cidr_exid_from_dbgu(u32 *cidr, u32 *exid)
  33 {
  34         struct device_node *np;
  35         void __iomem *regs;
  36
  37         np = of_find_compatible_node(NULL, NULL, "atmel,at91rm9200-dbgu");
  38         if (!np)
  39                 np = of_find_compatible_node(NULL, NULL,
  40                                              "atmel,at91sam9260-dbgu");
  41         if (!np)
  42                 return -ENODEV;
  43
  44         regs = of_iomap(np, 0);
  45         of_node_put(np);
  46
  47         if (!regs) {
  48                 pr_warn("Could not map DBGU iomem range");
  49                 return -ENXIO;
  50         }
  51
  52         *cidr = readl(regs + AT91_DBGU_CIDR);
  53         *exid = readl(regs + AT91_DBGU_EXID);
  54
  55         iounmap(regs);
  56
  57         return 0;
  58 }
  59
  60 static int __init at91_get_cidr_exid_from_chipid(u32 *cidr, u32 *exid)
  61 {
  62         struct device_node *np;
  63         void __iomem *regs;
  64
  65         np = of_find_compatible_node(NULL, NULL, "atmel,sama5d2-chipid");
  66         if (!np)
  67                 return -ENODEV;
  68
  69         regs = of_iomap(np, 0);
  70         of_node_put(np);
  71
  72         if (!regs) {
  73                 pr_warn("Could not map DBGU iomem range");
  74                 return -ENXIO;
  75         }
  76
  77         *cidr = readl(regs + AT91_CHIPID_CIDR);
  78         *exid = readl(regs + AT91_CHIPID_EXID);
  79
  80         iounmap(regs);
  81
  82         return 0;
  83 }
  84
  85 struct soc_device * __init at91_soc_init(const struct at91_soc *socs)
  86 {
  87         struct soc_device_attribute *soc_dev_attr;
  88         const struct at91_soc *soc;
  89         struct soc_device *soc_dev;
  90         u32 cidr, exid;
  91         int ret;
  92
  93         /*
  94          * With SAMA5D2 and later SoCs, CIDR and EXID registers are no more
  95          * in the dbgu device but in the chipid device whose purpose is only
  96          * to expose these two registers.
  97          */
  98         ret = at91_get_cidr_exid_from_dbgu(&cidr, &exid);
  99         if (ret)
 100                 ret = at91_get_cidr_exid_from_chipid(&cidr, &exid);
 101         if (ret) {
 102                 if (ret == -ENODEV)
 103                         pr_warn("Could not find identification node");
 104                 return NULL;
 105         }
 106
 107         for (soc = socs; soc->name; soc++) {
 108                 if (soc->cidr_match != (cidr & AT91_CIDR_MATCH_MASK))
 109                         continue;
 110
 111                 if (!(cidr & AT91_CIDR_EXT) || soc->exid_match == exid)
 112                         break;
 113         }
 114
 115         if (!soc->name) {
 116                 pr_warn("Could not find matching SoC description\n");
 117                 return NULL;
 118         }
 119
 120         soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
 121         if (!soc_dev_attr)
 122                 return NULL;
 123
 124         soc_dev_attr->family = soc->family;
 125         soc_dev_attr->soc_id = soc->name;
 126         soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%X",
 127                                            AT91_CIDR_VERSION(cidr));
 128         soc_dev = soc_device_register(soc_dev_attr);
 129         if (IS_ERR(soc_dev)) {
 130                 kfree(soc_dev_attr->revision);
 131                 kfree(soc_dev_attr);
 132                 pr_warn("Could not register SoC device\n");
 133                 return NULL;
 134         }
 135
 136         if (soc->family)
 137                 pr_info("Detected SoC family: %s\n", soc->family);
 138         pr_info("Detected SoC: %s, revision %X\n", soc->name,
 139                 AT91_CIDR_VERSION(cidr));
 140
 141         return soc_dev;
 142 }