mvebu-soc-id.c (4236B)
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 37static u32 soc_dev_id; 38static u32 soc_rev; 39static bool is_id_valid; 40 41static 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 48int 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 58static 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 113res_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 127clk_err: 128 of_node_put(child); 129 of_node_put(np); 130 131 return ret; 132} 133 134static 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} 149early_initcall(mvebu_soc_id_init); 150 151static 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} 178postcore_initcall(mvebu_soc_device);