arch/arm/mach-mvebu/mvebu-soc-id.c

   1 /*
   2  * ID and revision information for mvebu SoCs
   3  *
   4  * Copyright (C) 2014 Marvell
   5  *
   6  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2.  This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  *
  12  * All the mvebu SoCs have information related to their variant and
  13  * revision that can be read from the PCI control register. This is
  14  * done before the PCI initialization to avoid any conflict. Once the
  15  * ID and revision are retrieved, the mapping is freed.
  16  */
  17
  18 #define pr_fmt(fmt) "mvebu-soc-id: " fmt
  19
  20 #include <linux/clk.h>
  21 #include <linux/init.h>
  22 #include <linux/io.h>
  23 #include <linux/kernel.h>
  24 #include <linux/of.h>
  25 #include <linux/of_address.h>
  26 #include <linux/slab.h>
  27 #include <linux/sys_soc.h>
  28 #include "common.h"
  29 #include "mvebu-soc-id.h"
  30
  31 #define PCIE_DEV_ID_OFF         0x0
  32 #define PCIE_DEV_REV_OFF        0x8
  33
  34 #define SOC_ID_MASK         0xFFFF0000
  35 #define SOC_REV_MASK        0xFF
  36
  37 static u32 soc_dev_id;
  38 static u32 soc_rev;
  39 static bool is_id_valid;
  40
  41 static const struct of_device_id mvebu_pcie_of_match_table[] = {
  42         { .compatible = "marvell,armada-xp-pcie", },
  43         { .compatible = "marvell,armada-370-pcie", },
  44         { .compatible = "marvell,kirkwood-pcie" },
  45         {},
  46 };
  47
  48 int mvebu_get_soc_id(u32 *dev, u32 *rev)
  49 {
  50         if (is_id_valid) {
  51                 *dev = soc_dev_id;
  52                 *rev = soc_rev;
  53                 return 0;
  54         } else
  55                 return -ENODEV;
  56 }
  57
  58 static int __init get_soc_id_by_pci(void)
  59 {
  60         struct device_node *np;
  61         int ret = 0;
  62         void __iomem *pci_base;
  63         struct clk *clk;
  64         struct device_node *child;
  65
  66         np = of_find_matching_node(NULL, mvebu_pcie_of_match_table);
  67         if (!np)
  68                 return ret;
  69
  70         /*
  71          * ID and revision are available from any port, so we
  72          * just pick the first one
  73          */
  74         child = of_get_next_child(np, NULL);
  75         if (child == NULL) {
  76                 pr_err("cannot get pci node\n");
  77                 ret = -ENOMEM;
  78                 goto clk_err;
  79         }
  80
  81         clk = of_clk_get_by_name(child, NULL);
  82         if (IS_ERR(clk)) {
  83                 pr_err("cannot get clock\n");
  84                 ret = -ENOMEM;
  85                 goto clk_err;
  86         }
  87
  88         ret = clk_prepare_enable(clk);
  89         if (ret) {
  90                 pr_err("cannot enable clock\n");
  91                 goto clk_err;
  92         }
  93
  94         pci_base = of_iomap(child, 0);
  95         if (pci_base == NULL) {
  96                 pr_err("cannot map registers\n");
  97                 ret = -ENOMEM;
  98                 goto res_ioremap;
  99         }
 100
 101         /* SoC ID */
 102         soc_dev_id = readl(pci_base + PCIE_DEV_ID_OFF) >> 16;
 103
 104         /* SoC revision */
 105         soc_rev = readl(pci_base + PCIE_DEV_REV_OFF) & SOC_REV_MASK;
 106
 107         is_id_valid = true;
 108
 109         pr_info("MVEBU SoC ID=0x%X, Rev=0x%X\n", soc_dev_id, soc_rev);
 110
 111         iounmap(pci_base);
 112
 113 res_ioremap:
 114         /*
 115          * If the PCIe unit is actually enabled and we have PCI
 116          * support in the kernel, we intentionally do not release the
 117          * reference to the clock. We want to keep it running since
 118          * the bootloader does some PCIe link configuration that the
 119          * kernel is for now unable to do, and gating the clock would
 120          * make us loose this precious configuration.
 121          */
 122         if (!of_device_is_available(child) || !IS_ENABLED(CONFIG_PCI_MVEBU)) {
 123                 clk_disable_unprepare(clk);
 124                 clk_put(clk);
 125         }
 126
 127 clk_err:
 128         of_node_put(child);
 129         of_node_put(np);
 130
 131         return ret;
 132 }
 133
 134 static int __init mvebu_soc_id_init(void)
 135 {
 136
 137         /*
 138          * First try to get the ID and the revision by the system
 139          * register and use PCI registers only if it is not possible
 140          */
 141         if (!mvebu_system_controller_get_soc_id(&soc_dev_id, &soc_rev)) {
 142                 is_id_valid = true;
 143                 pr_info("MVEBU SoC ID=0x%X, Rev=0x%X\n", soc_dev_id, soc_rev);
 144                 return 0;
 145         }
 146
 147         return get_soc_id_by_pci();
 148 }
 149 early_initcall(mvebu_soc_id_init);
 150
 151 static int __init mvebu_soc_device(void)
 152 {
 153         struct soc_device_attribute *soc_dev_attr;
 154         struct soc_device *soc_dev;
 155
 156         /* Also protects against running on non-mvebu systems */
 157         if (!is_id_valid)
 158                 return 0;
 159
 160         soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
 161         if (!soc_dev_attr)
 162                 return -ENOMEM;
 163
 164         soc_dev_attr->family = kasprintf(GFP_KERNEL, "Marvell");
 165         soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%X", soc_rev);
 166         soc_dev_attr->soc_id = kasprintf(GFP_KERNEL, "%X", soc_dev_id);
 167
 168         soc_dev = soc_device_register(soc_dev_attr);
 169         if (IS_ERR(soc_dev)) {
 170                 kfree(soc_dev_attr->family);
 171                 kfree(soc_dev_attr->revision);
 172                 kfree(soc_dev_attr->soc_id);
 173                 kfree(soc_dev_attr);
 174         }
 175
 176         return 0;
 177 }
 178 postcore_initcall(mvebu_soc_device);