From e24328974a88aa8541e94e8bb8dfa2ade1b3c45d Mon Sep 17 00:00:00 2001 From: Donggeun Yoo Date: Wed, 2 Sep 2026 00:21:26 +0900 Subject: iio: proximity: vl53l0x-i2c: claim direct mode for raw reads vl53l0x_read_raw() starts a single-shot ranging measurement and reads back the result. Once the triggered buffer is enabled the sensor runs in continuous mode and its data-ready interrupt is routed to the trigger, so a concurrent in_distance_raw read disturbs the streaming setup and never gets its completion, returning -ETIMEDOUT. The original submission claimed direct mode here, but it was dropped during review because the driver had no buffer support at the time [1]. Continuous (buffered) mode was later added without restoring the claim [2], reintroducing the conflict. Reject direct reads while buffered capture is active by claiming direct mode around the measurement, as the vl53l1x sibling already does. Fixes: 762186c6e7b1 ("iio: proximity: vl53l0x-i2c: Added continuous mode support") Link: https://lore.kernel.org/linux-iio/20180911160300.GA9212@himanshu-Vostro-3559/ [1] Link: https://lore.kernel.org/linux-iio/20240909101508.263085-3-abhashkumarjha123@gmail.com/ [2] Signed-off-by: Donggeun Yoo Cc: stable@vger.kernel.org Signed-off-by: Jonathan Cameron --- lib/cache_maint.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 138 insertions(+) create mode 100644 lib/cache_maint.c (limited to 'lib/cache_maint.c') diff --git a/lib/cache_maint.c b/lib/cache_maint.c new file mode 100644 index 000000000..9256a9ffc --- /dev/null +++ b/lib/cache_maint.c @@ -0,0 +1,138 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generic support for Memory System Cache Maintenance operations. + * + * Coherency maintenance drivers register with this simple framework that will + * iterate over each registered instance to first kick off invalidation and + * then to wait until it is complete. + * + * If no implementations are registered yet cpu_cache_has_invalidate_memregion() + * will return false. If this runs concurrently with unregistration then a + * race exists but this is no worse than the case where the operations instance + * responsible for a given memory region has not yet registered. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static LIST_HEAD(cache_ops_instance_list); +static DECLARE_RWSEM(cache_ops_instance_list_lock); + +static void __cache_coherency_ops_instance_free(struct kref *kref) +{ + struct cache_coherency_ops_inst *cci = + container_of(kref, struct cache_coherency_ops_inst, kref); + kfree(cci); +} + +void cache_coherency_ops_instance_put(struct cache_coherency_ops_inst *cci) +{ + kref_put(&cci->kref, __cache_coherency_ops_instance_free); +} +EXPORT_SYMBOL_GPL(cache_coherency_ops_instance_put); + +static int cache_inval_one(struct cache_coherency_ops_inst *cci, void *data) +{ + if (!cci->ops) + return -EINVAL; + + return cci->ops->wbinv(cci, data); +} + +static int cache_inval_done_one(struct cache_coherency_ops_inst *cci) +{ + if (!cci->ops) + return -EINVAL; + + if (!cci->ops->done) + return 0; + + return cci->ops->done(cci); +} + +static int cache_invalidate_memregion(phys_addr_t addr, size_t size) +{ + int ret; + struct cache_coherency_ops_inst *cci; + struct cc_inval_params params = { + .addr = addr, + .size = size, + }; + + guard(rwsem_read)(&cache_ops_instance_list_lock); + list_for_each_entry(cci, &cache_ops_instance_list, node) { + ret = cache_inval_one(cci, ¶ms); + if (ret) + return ret; + } + list_for_each_entry(cci, &cache_ops_instance_list, node) { + ret = cache_inval_done_one(cci); + if (ret) + return ret; + } + + return 0; +} + +struct cache_coherency_ops_inst * +_cache_coherency_ops_instance_alloc(const struct cache_coherency_ops *ops, + size_t size) +{ + struct cache_coherency_ops_inst *cci; + + if (!ops || !ops->wbinv) + return NULL; + + cci = kzalloc(size, GFP_KERNEL); + if (!cci) + return NULL; + + cci->ops = ops; + INIT_LIST_HEAD(&cci->node); + kref_init(&cci->kref); + + return cci; +} +EXPORT_SYMBOL_NS_GPL(_cache_coherency_ops_instance_alloc, "CACHE_COHERENCY"); + +int cache_coherency_ops_instance_register(struct cache_coherency_ops_inst *cci) +{ + guard(rwsem_write)(&cache_ops_instance_list_lock); + list_add(&cci->node, &cache_ops_instance_list); + + return 0; +} +EXPORT_SYMBOL_NS_GPL(cache_coherency_ops_instance_register, "CACHE_COHERENCY"); + +void cache_coherency_ops_instance_unregister(struct cache_coherency_ops_inst *cci) +{ + guard(rwsem_write)(&cache_ops_instance_list_lock); + list_del(&cci->node); +} +EXPORT_SYMBOL_NS_GPL(cache_coherency_ops_instance_unregister, "CACHE_COHERENCY"); + +int cpu_cache_invalidate_memregion(phys_addr_t start, size_t len) +{ + return cache_invalidate_memregion(start, len); +} +EXPORT_SYMBOL_NS_GPL(cpu_cache_invalidate_memregion, "DEVMEM"); + +/* + * Used for optimization / debug purposes only as removal can race + * + * Machines that do not support invalidation, e.g. VMs, will not have any + * operations instance to register and so this will always return false. + */ +bool cpu_cache_has_invalidate_memregion(void) +{ + guard(rwsem_read)(&cache_ops_instance_list_lock); + return !list_empty(&cache_ops_instance_list); +} +EXPORT_SYMBOL_NS_GPL(cpu_cache_has_invalidate_memregion, "DEVMEM"); -- cgit v1.3.1