mvebu-soc-id.c
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/*
* ID and revision information for mvebu SoCs
*
* Copyright (C) 2014 Marvell
*
* Gregory CLEMENT <gregory.clement@free-electrons.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*
* All the mvebu SoCs have information related to their variant and
* revision that can be read from the PCI control register. This is
* done before the PCI initialization to avoid any conflict. Once the
* ID and revision are retrieved, the mapping is freed.
*/
#define pr_fmt(fmt) "mvebu-soc-id: " fmt
#include <linux/clk.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include "mvebu-soc-id.h"
#define PCIE_DEV_ID_OFF 0x0
#define PCIE_DEV_REV_OFF 0x8
#define SOC_ID_MASK 0xFFFF0000
#define SOC_REV_MASK 0xFF
static u32 soc_dev_id;
static u32 soc_rev;
static bool is_id_valid;
static const struct of_device_id mvebu_pcie_of_match_table[] = {
{ .compatible = "marvell,armada-xp-pcie", },
{ .compatible = "marvell,armada-370-pcie", },
{},
};
int mvebu_get_soc_id(u32 *dev, u32 *rev)
{
if (is_id_valid) {
*dev = soc_dev_id;
*rev = soc_rev;
return 0;
} else
return -1;
}
static int __init mvebu_soc_id_init(void)
{
struct device_node *np;
int ret = 0;
void __iomem *pci_base;
struct clk *clk;
struct device_node *child;
np = of_find_matching_node(NULL, mvebu_pcie_of_match_table);
if (!np)
return ret;
/*
* ID and revision are available from any port, so we
* just pick the first one
*/
child = of_get_next_child(np, NULL);
if (child == NULL) {
pr_err("cannot get pci node\n");
ret = -ENOMEM;
goto clk_err;
}
clk = of_clk_get_by_name(child, NULL);
if (IS_ERR(clk)) {
pr_err("cannot get clock\n");
ret = -ENOMEM;
goto clk_err;
}
ret = clk_prepare_enable(clk);
if (ret) {
pr_err("cannot enable clock\n");
goto clk_err;
}
pci_base = of_iomap(child, 0);
if (pci_base == NULL) {
pr_err("cannot map registers\n");
ret = -ENOMEM;
goto res_ioremap;
}
/* SoC ID */
soc_dev_id = readl(pci_base + PCIE_DEV_ID_OFF) >> 16;
/* SoC revision */
soc_rev = readl(pci_base + PCIE_DEV_REV_OFF) & SOC_REV_MASK;
is_id_valid = true;
pr_info("MVEBU SoC ID=0x%X, Rev=0x%X\n", soc_dev_id, soc_rev);
iounmap(pci_base);
res_ioremap:
/*
* If the PCIe unit is actually enabled and we have PCI
* support in the kernel, we intentionally do not release the
* reference to the clock. We want to keep it running since
* the bootloader does some PCIe link configuration that the
* kernel is for now unable to do, and gating the clock would
* make us loose this precious configuration.
*/
if (!of_device_is_available(child) || !IS_ENABLED(CONFIG_PCI_MVEBU)) {
clk_disable_unprepare(clk);
clk_put(clk);
}
clk_err:
of_node_put(child);
of_node_put(np);
return ret;
}
core_initcall(mvebu_soc_id_init);