Let the LiteX SoC Controller a register a restart handler, which resets the LiteX SoC by writing 1 to CSR_CTRL_RESET_ADDR.
Signed-off-by: Geert Uytterhoeven <ge...@linux-m68k.org> --- Tested with linux-on-litex-vexriscv. v3: - Rebase on top of openriscc/for-next, v2: - Rebase on top of v5.11-rc1, - Change reset handler priority to recommended default value of 128 (was 192). (v1 was not sent to a mailing list) --- drivers/soc/litex/litex_soc_ctrl.c | 33 +++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) diff --git a/drivers/soc/litex/litex_soc_ctrl.c b/drivers/soc/litex/litex_soc_ctrl.c index da17ba56b7956c84..834565101471d885 100644 --- a/drivers/soc/litex/litex_soc_ctrl.c +++ b/drivers/soc/litex/litex_soc_ctrl.c @@ -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 @@ -64,8 +69,20 @@ static int litex_check_csr_access(void __iomem *reg_addr) return 0; } -struct litex_soc_ctrl_device { +static struct litex_soc_ctrl_device { void __iomem *base; +} *soc_ctrl_dev; + +static int litex_reset_handler(struct notifier_block *this, unsigned long mode, + void *cmd) +{ + litex_write32(soc_ctrl_dev->base + RESET_REG_OFF, RESET_REG_VALUE); + return NOTIFY_DONE; +} + +static struct notifier_block litex_reset_nb = { + .notifier_call = litex_reset_handler, + .priority = 128, }; static const struct of_device_id litex_soc_ctrl_of_match[] = { @@ -77,7 +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 +104,17 @@ 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; + + error = register_restart_handler(&litex_reset_nb); + if (error) { + dev_warn(&pdev->dev, "cannot register restart handler: %d\n", + error); + } + + return 0; } static struct platform_driver litex_soc_ctrl_driver = { -- 2.25.1