146 lines
3.9 KiB
C
146 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* LiteX SoC Controller Driver
|
|
*
|
|
* Copyright (C) 2020 Antmicro <www.antmicro.com>
|
|
*
|
|
*/
|
|
|
|
#include <linux/litex.h>
|
|
#include <linux/device.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/of.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/printk.h>
|
|
#include <linux/module.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/io.h>
|
|
#include <linux/reboot.h>
|
|
|
|
/* reset register located at the base address */
|
|
#define RESET_REG_OFF 0x00
|
|
#define RESET_REG_VALUE 0x00000001
|
|
|
|
#define SCRATCH_REG_OFF 0x04
|
|
#define SCRATCH_REG_VALUE 0x12345678
|
|
#define SCRATCH_TEST_VALUE 0xdeadbeef
|
|
|
|
/*
|
|
* Check LiteX CSR read/write access
|
|
*
|
|
* This function reads and writes a scratch register in order to verify if CSR
|
|
* access works.
|
|
*
|
|
* In case any problems are detected, the driver should panic.
|
|
*
|
|
* Access to the LiteX CSR is, by design, done in CPU native endianness.
|
|
* The driver should not dynamically configure access functions when
|
|
* the endianness mismatch is detected. Such situation indicates problems in
|
|
* the soft SoC design and should be solved at the LiteX generator level,
|
|
* not in the software.
|
|
*/
|
|
static int litex_check_csr_access(void __iomem *reg_addr)
|
|
{
|
|
unsigned long reg;
|
|
|
|
reg = litex_read32(reg_addr + SCRATCH_REG_OFF);
|
|
|
|
if (reg != SCRATCH_REG_VALUE) {
|
|
panic("Scratch register read error - the system is probably broken! Expected: 0x%x but got: 0x%lx",
|
|
SCRATCH_REG_VALUE, reg);
|
|
return -EINVAL;
|
|
}
|
|
|
|
litex_write32(reg_addr + SCRATCH_REG_OFF, SCRATCH_TEST_VALUE);
|
|
reg = litex_read32(reg_addr + SCRATCH_REG_OFF);
|
|
|
|
if (reg != SCRATCH_TEST_VALUE) {
|
|
panic("Scratch register write error - the system is probably broken! Expected: 0x%x but got: 0x%lx",
|
|
SCRATCH_TEST_VALUE, reg);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* restore original value of the SCRATCH register */
|
|
litex_write32(reg_addr + SCRATCH_REG_OFF, SCRATCH_REG_VALUE);
|
|
|
|
pr_info("LiteX SoC Controller driver initialized: subreg:%d, align:%d",
|
|
LITEX_SUBREG_SIZE, LITEX_SUBREG_ALIGN);
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct litex_soc_ctrl_device {
|
|
void __iomem *base;
|
|
struct notifier_block reset_nb;
|
|
};
|
|
|
|
static int litex_reset_handler(struct notifier_block *this, unsigned long mode,
|
|
void *cmd)
|
|
{
|
|
struct litex_soc_ctrl_device *soc_ctrl_dev =
|
|
container_of(this, struct litex_soc_ctrl_device, reset_nb);
|
|
|
|
litex_write32(soc_ctrl_dev->base + RESET_REG_OFF, RESET_REG_VALUE);
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
#ifdef CONFIG_OF
|
|
static const struct of_device_id litex_soc_ctrl_of_match[] = {
|
|
{.compatible = "litex,soc-controller"},
|
|
{},
|
|
};
|
|
MODULE_DEVICE_TABLE(of, litex_soc_ctrl_of_match);
|
|
#endif /* CONFIG_OF */
|
|
|
|
static int litex_soc_ctrl_probe(struct platform_device *pdev)
|
|
{
|
|
struct litex_soc_ctrl_device *soc_ctrl_dev;
|
|
int error;
|
|
|
|
soc_ctrl_dev = devm_kzalloc(&pdev->dev, sizeof(*soc_ctrl_dev), GFP_KERNEL);
|
|
if (!soc_ctrl_dev)
|
|
return -ENOMEM;
|
|
|
|
soc_ctrl_dev->base = devm_platform_ioremap_resource(pdev, 0);
|
|
if (IS_ERR(soc_ctrl_dev->base))
|
|
return PTR_ERR(soc_ctrl_dev->base);
|
|
|
|
error = litex_check_csr_access(soc_ctrl_dev->base);
|
|
if (error)
|
|
return error;
|
|
|
|
platform_set_drvdata(pdev, soc_ctrl_dev);
|
|
|
|
soc_ctrl_dev->reset_nb.notifier_call = litex_reset_handler;
|
|
soc_ctrl_dev->reset_nb.priority = 128;
|
|
error = register_restart_handler(&soc_ctrl_dev->reset_nb);
|
|
if (error) {
|
|
dev_warn(&pdev->dev, "cannot register restart handler: %d\n",
|
|
error);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int litex_soc_ctrl_remove(struct platform_device *pdev)
|
|
{
|
|
struct litex_soc_ctrl_device *soc_ctrl_dev = platform_get_drvdata(pdev);
|
|
|
|
unregister_restart_handler(&soc_ctrl_dev->reset_nb);
|
|
return 0;
|
|
}
|
|
|
|
static struct platform_driver litex_soc_ctrl_driver = {
|
|
.driver = {
|
|
.name = "litex-soc-controller",
|
|
.of_match_table = of_match_ptr(litex_soc_ctrl_of_match)
|
|
},
|
|
.probe = litex_soc_ctrl_probe,
|
|
.remove = litex_soc_ctrl_remove,
|
|
};
|
|
|
|
module_platform_driver(litex_soc_ctrl_driver);
|
|
MODULE_DESCRIPTION("LiteX SoC Controller driver");
|
|
MODULE_AUTHOR("Antmicro <www.antmicro.com>");
|
|
MODULE_LICENSE("GPL v2");
|