Commit 3706f9f7 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Stafford Horne
Browse files

drivers/soc/litex: Add restart handler 



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: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: default avatarJoel Stanley <joel@jms.id.au>
Signed-off-by: default avatarStafford Horne <shorne@gmail.com>
parent 803c72c8

drivers/soc/litex/litex_soc_ctrl.c

+41 −1
Original line number Diff line number Diff line
@@ -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);