linux/arch/arm/mach-mvebu/mvebu-soc-id.c
Gregory CLEMENT 9674d4a3cf ARM: mvebu: Use system controller to get the soc id when possible
On Armada 38x it is possible to get the SoC Id and the revision
without using the PCI register. Accessing the PCI registers implies
enabling its clock and, because of the initialization issue, not
keeping them enable. So if possible it is better to avoid it.

Armada 370 and Armada XP provides the SoC ID values from the system
controller but not the revision.

Armada 375 provides both but the SoC ID value looks buggy (0x6660
instead of 0x6720).

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1403538128-27859-1-git-send-email-gregory.clement@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
2014-06-30 17:40:59 +00:00

179 lines
4.1 KiB
C

/*
* 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 <linux/slab.h>
#include <linux/sys_soc.h>
#include "common.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", },
{ .compatible = "marvell,kirkwood-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 -ENODEV;
}
static int __init get_soc_id_by_pci(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;
}
static int __init mvebu_soc_id_init(void)
{
/*
* First try to get the ID and the revision by the system
* register and use PCI registers only if it is not possible
*/
if (!mvebu_system_controller_get_soc_id(&soc_dev_id, &soc_rev)) {
is_id_valid = true;
pr_info("MVEBU SoC ID=0x%X, Rev=0x%X\n", soc_dev_id, soc_rev);
return 0;
}
return get_soc_id_by_pci();
}
early_initcall(mvebu_soc_id_init);
static int __init mvebu_soc_device(void)
{
struct soc_device_attribute *soc_dev_attr;
struct soc_device *soc_dev;
/* Also protects against running on non-mvebu systems */
if (!is_id_valid)
return 0;
soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
if (!soc_dev_attr)
return -ENOMEM;
soc_dev_attr->family = kasprintf(GFP_KERNEL, "Marvell");
soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%X", soc_rev);
soc_dev_attr->soc_id = kasprintf(GFP_KERNEL, "%X", soc_dev_id);
soc_dev = soc_device_register(soc_dev_attr);
if (IS_ERR(soc_dev)) {
kfree(soc_dev_attr->family);
kfree(soc_dev_attr->revision);
kfree(soc_dev_attr->soc_id);
kfree(soc_dev_attr);
}
return 0;
}
postcore_initcall(mvebu_soc_device);