forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
143 lines
3.8 KiB
143 lines
3.8 KiB
// 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/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"); |
|
|
|
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");
|
|
|