diff --git a/drivers/reset/reset-socfpga.c b/drivers/reset/reset-socfpga.c index 244db51d85..cb8312619f 100644 --- a/drivers/reset/reset-socfpga.c +++ b/drivers/reset/reset-socfpga.c @@ -27,6 +27,36 @@ struct socfpga_reset_data { void __iomem *modrst_base; }; +/* + * For compatibility with Kernels that don't support peripheral reset, this + * driver can keep the old behaviour of not asserting peripheral reset before + * starting the OS and deasserting all peripheral resets (enabling all + * peripherals). + * + * For that, the reset driver checks the environment variable + * "socfpga_legacy_reset_compat". If this variable is '1', perihperals are not + * reset again once taken out of reset and all peripherals in 'permodrst' are + * taken out of reset before booting into the OS. + * Note that this should be required for gen5 systems only that are running + * Linux kernels without proper peripheral reset support for all drivers used. + */ +static bool socfpga_reset_keep_enabled(void) +{ +#if !defined(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(ENV_SUPPORT) + const char *env_str; + long val; + + env_str = env_get("socfpga_legacy_reset_compat"); + if (env_str) { + val = simple_strtol(env_str, NULL, 0); + if (val == 1) + return true; + } +#endif + + return false; +} + static int socfpga_reset_assert(struct reset_ctl *reset_ctl) { struct socfpga_reset_data *data = dev_get_priv(reset_ctl->dev); @@ -90,6 +120,18 @@ static int socfpga_reset_probe(struct udevice *dev) return 0; } +static int socfpga_reset_remove(struct udevice *dev) +{ + struct socfpga_reset_data *data = dev_get_priv(dev); + + if (socfpga_reset_keep_enabled()) { + puts("Deasserting all peripheral resets\n"); + writel(0, data->modrst_base + 4); + } + + return 0; +} + static const struct udevice_id socfpga_reset_match[] = { { .compatible = "altr,rst-mgr" }, { /* sentinel */ }, @@ -102,4 +144,6 @@ U_BOOT_DRIVER(socfpga_reset) = { .probe = socfpga_reset_probe, .priv_auto_alloc_size = sizeof(struct socfpga_reset_data), .ops = &socfpga_reset_ops, + .remove = socfpga_reset_remove, + .flags = DM_FLAG_OS_PREPARE, };