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drivers/soc/litex: Add restart handler

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Let the LiteX SoC Controller register a restart handler, which resets
the LiteX SoC by writing 1 to CSR_CTRL_RESET_ADDR.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Stafford Horne <shorne@gmail.com>
This commit is contained in:
Geert Uytterhoeven 2021-01-19 09:09:38 +01:00 committed by Stafford Horne
parent 803c72c854
commit 3706f9f76a
1 changed files with 41 additions and 1 deletions
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42
drivers/soc/litex/litex_soc_ctrl.c
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@ -15,6 +15,11 @@
#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
@ -66,8 +71,19 @@ static int litex_check_csr_access(void __iomem *reg_addr)
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;
}
static const struct of_device_id litex_soc_ctrl_of_match[] = {
{.compatible = "litex,soc-controller"},
{},
@ -78,6 +94,7 @@ MODULE_DEVICE_TABLE(of, litex_soc_ctrl_of_match);
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)
@ -87,7 +104,29 @@ static int litex_soc_ctrl_probe(struct platform_device *pdev)
if (IS_ERR(soc_ctrl_dev->base))
return PTR_ERR(soc_ctrl_dev->base);
return litex_check_csr_access(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 = {
@ -96,6 +135,7 @@ static struct platform_driver litex_soc_ctrl_driver = {
.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);