diff options
Diffstat (limited to 'drivers/base/featctrl.c')
| -rw-r--r-- | drivers/base/featctrl.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/drivers/base/featctrl.c b/drivers/base/featctrl.c new file mode 100644 index 0000000000..153720e5ee --- /dev/null +++ b/drivers/base/featctrl.c @@ -0,0 +1,159 @@ +// SPDX-License-Identifier: GPL-2.0-only +// SPDX-FileCopyrightText: 2022 Ahmad Fatoum, Pengutronix + +#define pr_fmt(fmt) "featctrl: " fmt + +#include <common.h> +#include <driver.h> +#include <errno.h> +#include <of.h> + +#include <featctrl.h> + +/* List of registered feature controllers */ +static LIST_HEAD(of_feature_controllers); + +/** + * feature_controller_register() - Register a feature controller + * @feat: Pointer to feature controller + */ +int feature_controller_register(struct feature_controller *feat) +{ + struct device_node *np = dev_of_node(feat->dev); + + if (!np) + return -EINVAL; + + list_add(&feat->list, &of_feature_controllers); + dev_dbg(feat->dev, "Registering feature controller\n"); + return 0; +} +EXPORT_SYMBOL_GPL(feature_controller_register); + +/** + * featctrl_get_from_provider() - Look-up feature gate + * @spec: OF phandle args to use for look-up + * @gateid: ID of feature controller gate populated on successful lookup + * + * Looks for a feature controller under the node specified by @spec. + * + * Returns a valid pointer to struct feature_controller on success or ERR_PTR() + * on failure. + */ +static struct feature_controller *featctrl_get_from_provider(struct of_phandle_args *spec, + unsigned *gateid) +{ + struct feature_controller *featctrl; + int ret; + + ret = of_device_ensure_probed(spec->np); + if (ret < 0) + return ERR_PTR(ret); + + if (spec->args_count > 1) + return ERR_PTR(-EINVAL); + + /* Check if we have such a controller in our array */ + list_for_each_entry(featctrl, &of_feature_controllers, list) { + if (dev_of_node(featctrl->dev) == spec->np) { + *gateid = spec->args_count ? spec->args[0] : 0; + return featctrl; + } + } + + return ERR_PTR(-ENOENT); +} + +/** + * of_feature_controller_check - Check whether a feature controller gates the device + * @np: Device node to check + * + * Parse device's OF node to find a feature controller specifier. If such is + * found, checks it to determine whether device is gated. + * + * Returns FEATCTRL_GATED if a specified feature controller gates the device + * and FEATCTRL_OKAY if none do. On error a negative error code is returned. + */ +int of_feature_controller_check(struct device_node *np) +{ + struct of_phandle_args featctrl_args; + struct feature_controller *featctrl; + int ret, err = 0, i, ngates; + + ngates = of_count_phandle_with_args(np, "barebox,feature-gates", + "#feature-cells"); + if (ngates <= 0) + return FEATCTRL_OKAY; + + for (i = 0; i < ngates; i++) { + unsigned gateid = 0; + + ret = of_parse_phandle_with_args(np, "barebox,feature-gates", + "#feature-cells", i, &featctrl_args); + if (ret < 0) + return ret; + + featctrl = featctrl_get_from_provider(&featctrl_args, &gateid); + if (IS_ERR(featctrl)) { + ret = PTR_ERR(featctrl); + pr_debug("%s() failed to find feature controller: %pe\n", + __func__, ERR_PTR(ret)); + /* + * Assume that missing featctrls are unresolved + * dependency are report them as deferred + */ + return (ret == -ENOENT) ? -EPROBE_DEFER : ret; + } + + ret = featctrl->check(featctrl, gateid); + + dev_dbg(featctrl->dev, "checking %pOF: %d\n", np, ret); + + if (ret == FEATCTRL_OKAY) + return FEATCTRL_OKAY; + if (ret != FEATCTRL_GATED) + err = ret; + } + + return err ?: FEATCTRL_GATED; +} +EXPORT_SYMBOL_GPL(of_feature_controller_check); + +static int of_featctrl_fixup(struct device_node *root, void *context) +{ + struct device_node *srcnp, *dstnp; + int err = 0; + + for_each_node_with_property(srcnp, "barebox,feature-gates") { + int ret; + + ret = of_feature_controller_check(srcnp); + if (ret < 0) + err = ret; + if (ret != FEATCTRL_GATED) + continue; + + dstnp = of_get_node_by_reproducible_name(root, srcnp); + if (!dstnp) { + pr_debug("gated node %pOF not in fixup DT\n", srcnp); + continue; + } + + pr_debug("fixing up gating of node %pOF\n", dstnp); + /* Convention is deleting non-existing CPUs, not disable them. */ + if (of_property_match_string(srcnp, "device_type", "cpu") >= 0) + of_delete_node(dstnp); + else + of_device_disable(dstnp); + } + + return err; +} + +static __maybe_unused int of_featctrl_fixup_register(void) +{ + return of_register_fixup(of_featctrl_fixup, NULL); +} +#ifdef CONFIG_FEATURE_CONTROLLER_FIXUP +device_initcall(of_featctrl_fixup_register); +#endif |