// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
*
* Authors:
* Serge Semin <[email protected]>
*
* Baikal-T1 AXI-bus driver
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/bitfield.h>
#include <linux/device.h>
#include <linux/atomic.h>
#include <linux/regmap.h>
#include <linux/platform_device.h>
#include <linux/mfd/syscon.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/nmi.h>
#include <linux/of.h>
#include <linux/clk.h>
#include <linux/reset.h>
#include <linux/sysfs.h>
#define BT1_AXI_WERRL 0x110
#define BT1_AXI_WERRH 0x114
#define BT1_AXI_WERRH_TYPE BIT(23)
#define BT1_AXI_WERRH_ADDR_FLD 24
#define BT1_AXI_WERRH_ADDR_MASK GENMASK(31, BT1_AXI_WERRH_ADDR_FLD)
/*
* struct bt1_axi - Baikal-T1 AXI-bus private data
* @dev: Pointer to the device structure.
* @qos_regs: AXI Interconnect QoS tuning registers.
* @sys_regs: Baikal-T1 System Controller registers map.
* @irq: Errors IRQ number.
* @aclk: AXI reference clock.
* @arst: AXI Interconnect reset line.
* @count: Number of errors detected.
*/
struct bt1_axi {
struct device *dev;
void __iomem *qos_regs;
struct regmap *sys_regs;
int irq;
struct clk *aclk;
struct reset_control *arst;
atomic_t count;
};
static irqreturn_t bt1_axi_isr(int irq, void *data)
{
struct bt1_axi *axi = data;
u32 low = 0, high = 0;
regmap_read(axi->sys_regs, BT1_AXI_WERRL, &low);
regmap_read(axi->sys_regs, BT1_AXI_WERRH, &high);
dev_crit_ratelimited(axi->dev,
"AXI-bus fault %d: %s at 0x%x%08x\n",
atomic_inc_return(&axi->count),
high & BT1_AXI_WERRH_TYPE ? "no slave" : "slave protocol error",
high, low);
/*
* Print backtrace on each CPU. This might be pointless if the fault
* has happened on the same CPU as the IRQ handler is executed or
* the other core proceeded further execution despite the error.
* But if it's not, by looking at the trace we would get straight to
* the cause of the problem.
*/
trigger_all_cpu_backtrace();
return IRQ_HANDLED;
}
static void bt1_axi_clear_data(void *data)
{
struct bt1_axi *axi = data;
struct platform_device *pdev = to_platform_device(axi->dev);
platform_set_drvdata(pdev, NULL);
}
static struct bt1_axi *bt1_axi_create_data(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct bt1_axi *axi;
int ret;
axi = devm_kzalloc(dev, sizeof(*axi), GFP_KERNEL);
if (!axi)
return ERR_PTR(-ENOMEM);
ret = devm_add_action(dev, bt1_axi_clear_data, axi);
if (ret) {
dev_err(dev, "Can't add AXI EHB data clear action\n");
return ERR_PTR(ret);
}
axi->dev = dev;
atomic_set(&axi->count, 0);
platform_set_drvdata(pdev, axi);
return axi;
}
static int bt1_axi_request_regs(struct bt1_axi *axi)
{
struct platform_device *pdev = to_platform_device(axi->dev);
struct device *dev = axi->dev;
axi->sys_regs = syscon_regmap_lookup_by_phandle(dev->of_node, "syscon");
if (IS_ERR(axi->sys_regs)) {
dev_err(dev, "Couldn't find syscon registers\n");
return PTR_ERR(axi->sys_regs);
}
axi->qos_regs = devm_platform_ioremap_resource_byname(pdev, "qos");
if (IS_ERR(axi->qos_regs))
dev_err(dev, "Couldn't map AXI-bus QoS registers\n");
return PTR_ERR_OR_ZERO(axi->qos_regs);
}
static int bt1_axi_request_rst(struct bt1_axi *axi)
{
int ret;
axi->arst = devm_reset_control_get_optional_exclusive(axi->dev, "arst");
if (IS_ERR(axi->arst))
return dev_err_probe(axi->dev, PTR_ERR(axi->arst),
"Couldn't get reset control line\n");
ret = reset_control_deassert(axi->arst);
if (ret)
dev_err(axi->dev, "Failed to deassert the reset line\n");
return ret;
}
static int bt1_axi_request_clk(struct bt1_axi *axi)
{
axi->aclk = devm_clk_get_enabled(axi->dev, "aclk");
if (IS_ERR(axi->aclk))
return dev_err_probe(axi->dev, PTR_ERR(axi->aclk),
"Couldn't get AXI Interconnect clock\n");
return 0;
}
static int bt1_axi_request_irq(struct bt1_axi *axi)
{
struct platform_device *pdev = to_platform_device(axi->dev);
int ret;
axi->irq = platform_get_irq(pdev, 0);
if (axi->irq < 0)
return axi->irq;
ret = devm_request_irq(axi->dev, axi->irq, bt1_axi_isr, IRQF_SHARED,
"bt1-axi", axi);
if (ret)
dev_err(axi->dev, "Couldn't request AXI EHB IRQ\n");
return ret;
}
static ssize_t count_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct bt1_axi *axi = dev_get_drvdata(dev);
return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&axi->count));
}
static DEVICE_ATTR_RO(count);
static ssize_t inject_error_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
return scnprintf(buf, PAGE_SIZE, "Error injection: bus unaligned\n");
}
static ssize_t inject_error_store(struct device *dev,
struct device_attribute *attr,
const char *data, size_t count)
{
struct bt1_axi *axi = dev_get_drvdata(dev);
/*
* Performing unaligned read from the memory will cause the CM2 bus
* error while unaligned writing - the AXI bus write error handled
* by this driver.
*/
if (sysfs_streq(data, "bus"))
readb(axi->qos_regs);
else if (sysfs_streq(data, "unaligned"))
writeb(0, axi->qos_regs);
else
return -EINVAL;
return count;
}
static DEVICE_ATTR_RW(inject_error);
static struct attribute *bt1_axi_sysfs_attrs[] = {
&dev_attr_count.attr,
&dev_attr_inject_error.attr,
NULL
};
ATTRIBUTE_GROUPS(bt1_axi_sysfs);
static void bt1_axi_remove_sysfs(void *data)
{
struct bt1_axi *axi = data;
device_remove_groups(axi->dev, bt1_axi_sysfs_groups);
}
static int bt1_axi_init_sysfs(struct bt1_axi *axi)
{
int ret;
ret = device_add_groups(axi->dev, bt1_axi_sysfs_groups);
if (ret) {
dev_err(axi->dev, "Failed to add sysfs files group\n");
return ret;
}
ret = devm_add_action_or_reset(axi->dev, bt1_axi_remove_sysfs, axi);
if (ret)
dev_err(axi->dev, "Can't add AXI EHB sysfs remove action\n");
return ret;
}
static int bt1_axi_probe(struct platform_device *pdev)
{
struct bt1_axi *axi;
int ret;
axi = bt1_axi_create_data(pdev);
if (IS_ERR(axi))
return PTR_ERR(axi);
ret = bt1_axi_request_regs(axi);
if (ret)
return ret;
ret = bt1_axi_request_rst(axi);
if (ret)
return ret;
ret = bt1_axi_request_clk(axi);
if (ret)
return ret;
ret = bt1_axi_request_irq(axi);
if (ret)
return ret;
ret = bt1_axi_init_sysfs(axi);
if (ret)
return ret;
return 0;
}
static const struct of_device_id bt1_axi_of_match[] = {
{ .compatible = "baikal,bt1-axi" },
{ }
};
MODULE_DEVICE_TABLE(of, bt1_axi_of_match);
static struct platform_driver bt1_axi_driver = {
.probe = bt1_axi_probe,
.driver = {
.name = "bt1-axi",
.of_match_table = bt1_axi_of_match
}
};
module_platform_driver(bt1_axi_driver);
MODULE_AUTHOR("Serge Semin <[email protected]>");
MODULE_DESCRIPTION("Baikal-T1 AXI-bus driver");
Codebase Browser
linux