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a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1742505215; bh=qT3pRQIRt1i35oXtu0ODXFreqqI/+Y7zQS4P0enG44U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iaMJ49FB16G+FlJRuy97OCfjA+ZbWBl3XVzcBMcaKwrB06G5d36541muYB5cmaXHu YMMt/nHuOhUyOpB+eQ4xO2cyWMn+axk3d7aTdXz2tEEpUBygHFk0M9oDEEwHS0uJPd EKgLazyXP8IsrH66Cm5uouuHXXVNfRPzAwLWxRrU= Date: Thu, 20 Mar 2025 14:12:15 -0700 From: Greg KH To: Jonathan Cameron Cc: linux-cxl@vger.kernel.org, linux-arm-kernel@lists.infradead.org, james.morse@arm.com, conor@kernel.org, Yicong Yang , linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linuxarm@huawei.com, Yushan Wang , linux-mm@kvack.org, Lorenzo Pieralisi , Mark Rutland , Catalin Marinas , Will Deacon , Dan Williams Subject: Re: [RFC PATCH 3/6] cache: coherency device class Message-ID: <2025032013-venus-request-b026@gregkh> References: <20250320174118.39173-1-Jonathan.Cameron@huawei.com> <20250320174118.39173-4-Jonathan.Cameron@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250320174118.39173-4-Jonathan.Cameron@huawei.com> X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 233368000E X-Stat-Signature: 659dnbnxf1dr43qfkef689x3nfxuqkij X-HE-Tag: 1742505217-818601 X-HE-Meta: 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 ZCTwPvRs kIjDR2pSOMw9pjMjLuzg74YIjQbO8p+Ed+ryWnZ1yV1PJz3nLIctuB0RcxmQD18nfl1yQE7PcVlgtajlxjD/Lj9zdzR5BCrdxDdKqYaEl4X/tvcigMPn2ci0I+hQHOLl1B+V0qqwJ+VJpkdOBX1KT15V40r7BYMrOtH8gNBlFU/wQPfzSOlE6UDc8tM/CCS4Iq1UXAmCv5iVvdQeR3f7FBqQk8m1+EPxxPAHdu+BUHm23Zd7i2Sruriy5IPulxl3H+j6EbWms0Qh7RWbCwCh+yTXXHURCcGCmW6Y+GIOOZnqw889fNuFhMX8O+5JNL2/PIJDu X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Mar 20, 2025 at 05:41:15PM +0000, Jonathan Cameron wrote: > --- a/drivers/cache/Kconfig > +++ b/drivers/cache/Kconfig > @@ -1,6 +1,12 @@ > # SPDX-License-Identifier: GPL-2.0 > menu "Cache Drivers" > > +config CACHE_COHERENCY_CLASS > + bool "Cache coherency control class" Why can't this be a module? And why would anyone want to turn it off? > + help > + Class to which coherency control drivers register allowing core kernel > + subsystems to issue invalidations and similar coherency operations. What "core kernel subsystems"? > + > config AX45MP_L2_CACHE > bool "Andes Technology AX45MP L2 Cache controller" > depends on RISCV Shouldn't all of these now depend on CACHE_COHERENCY_CLASS? > diff --git a/drivers/cache/Makefile b/drivers/cache/Makefile > index 55c5e851034d..b72b20f4248f 100644 > --- a/drivers/cache/Makefile > +++ b/drivers/cache/Makefile > @@ -3,3 +3,5 @@ > obj-$(CONFIG_AX45MP_L2_CACHE) += ax45mp_cache.o > obj-$(CONFIG_SIFIVE_CCACHE) += sifive_ccache.o > obj-$(CONFIG_STARFIVE_STARLINK_CACHE) += starfive_starlink_cache.o > + > +obj-$(CONFIG_CACHE_COHERENCY_CLASS) += coherency_core.o Why the blank line? > diff --git a/drivers/cache/coherency_core.c b/drivers/cache/coherency_core.c > new file mode 100644 > index 000000000000..52cb4ceae00c > --- /dev/null > +++ b/drivers/cache/coherency_core.c > @@ -0,0 +1,130 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Class to manage OS controlled coherency agents within the system. > + * Specifically to enable operations such as write back and invalidate. > + * > + * Copyright: Huawei 2025 > + * Some elements based on fwctl class as an example of a modern > + * lightweight class. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include > + > +static DEFINE_IDA(cache_coherency_ida); > + > +static void cache_coherency_device_release(struct device *device) > +{ > + struct cache_coherency_device *ccd = > + container_of(device, struct cache_coherency_device, dev); > + > + ida_free(&cache_coherency_ida, ccd->id); > +} > + > +static struct class cache_coherency_class = { > + .name = "cache_coherency", > + .dev_release = cache_coherency_device_release, > +}; > + > +static int cache_inval_one(struct device *dev, void *data) > +{ > + struct cache_coherency_device *ccd = > + container_of(dev, struct cache_coherency_device, dev); > + > + if (!ccd->ops) > + return -EINVAL; > + > + return ccd->ops->wbinv(ccd, data); > +} > + > +static int cache_inval_done_one(struct device *dev, void *data) > +{ > + struct cache_coherency_device *ccd = > + container_of(dev, struct cache_coherency_device, dev); > + if (!ccd->ops) > + return -EINVAL; > + > + return ccd->ops->done(ccd); > +} > + > +static int cache_invalidate_memregion(int res_desc, > + phys_addr_t addr, size_t size) > +{ > + int ret; > + struct cc_inval_params params = { > + .addr = addr, > + .size = size, > + }; > + > + ret = class_for_each_device(&cache_coherency_class, NULL, ¶ms, > + cache_inval_one); > + if (ret) > + return ret; > + > + return class_for_each_device(&cache_coherency_class, NULL, NULL, > + cache_inval_done_one); > +} > + > +static const struct system_cache_flush_method cache_flush_method = { > + .invalidate_memregion = cache_invalidate_memregion, > +}; > + > +struct cache_coherency_device * > +_cache_coherency_alloc_device(struct device *parent, > + const struct coherency_ops *ops, size_t size) > +{ > + > + if (!ops || !ops->wbinv) > + return NULL; > + > + struct cache_coherency_device *ccd __free(kfree) = kzalloc(size, GFP_KERNEL); > + > + if (!ccd) > + return NULL; > + > + ccd->dev.class = &cache_coherency_class; > + ccd->dev.parent = parent; > + ccd->ops = ops; > + ccd->id = ida_alloc(&cache_coherency_ida, GFP_KERNEL); > + > + if (dev_set_name(&ccd->dev, "cache_coherency%d", ccd->id)) > + return NULL; > + > + device_initialize(&ccd->dev); > + > + return_ptr(ccd); > +} > +EXPORT_SYMBOL_NS_GPL(_cache_coherency_alloc_device, "CACHE_COHERENCY"); > + > +int cache_coherency_device_register(struct cache_coherency_device *ccd) > +{ > + return device_add(&ccd->dev); > +} > +EXPORT_SYMBOL_NS_GPL(cache_coherency_device_register, "CACHE_COHERENCY"); > + > +void cache_coherency_device_unregister(struct cache_coherency_device *ccd) > +{ > + device_del(&ccd->dev); > +} > +EXPORT_SYMBOL_NS_GPL(cache_coherency_device_unregister, "CACHE_COHERENCY"); > + > +static int __init cache_coherency_init(void) > +{ > + int ret; > + > + ret = class_register(&cache_coherency_class); > + if (ret) > + return ret; > + > + //TODO: generalize > + arm64_set_sys_cache_flush_method(&cache_flush_method); I'm guessing this will blow up the build on non-x86 builds :) > +struct cache_coherency_device { > + struct device dev; > + const struct coherency_ops *ops; > + int id; > +}; Classes are normally for user/kernel apis, what is this going to be used for? I don't see any new user/kernel apis happening, so why do you need a struct device to be created? thanks, greg k-h