Re: [PATCH v2 2/8] generic: Support ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION

From: Yicong Yang <yangyicong@hisilicon.com>

ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION provides the mechanism for
invalidate certain memory regions in a cache-incoherent manner.
Currently is used by NVIDMM adn CXL memory. This is mainly done
by the system component and is implementation define per spec.
Provides a method for the platforms register their own invalidate
method and implement ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION.

Architectures can opt in for this support via
CONFIG_GENERIC_CPU_CACHE_INVALIDATE_MEMREGION.

Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/base/Kconfig             |  3 +++
 drivers/base/Makefile            |  1 +
 drivers/base/cache.c             | 46 ++++++++++++++++++++++++++++++++
 include/asm-generic/cacheflush.h | 12 +++++++++
 4 files changed, 62 insertions(+)

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 064eb52ff7e2..cc6df87a0a96 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig

@@ -181,6 +181,9 @@ config SYS_HYPERVISOR
 	bool
 	default n
 
+config GENERIC_CPU_CACHE_INVALIDATE_MEMREGION
+	bool
+
 config GENERIC_CPU_DEVICES
 	bool
 	default n

diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 8074a10183dc..0fbfa4300b98 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile

@@ -26,6 +26,7 @@ obj-$(CONFIG_DEV_COREDUMP) += devcoredump.o
 obj-$(CONFIG_GENERIC_MSI_IRQ) += platform-msi.o
 obj-$(CONFIG_GENERIC_ARCH_TOPOLOGY) += arch_topology.o
 obj-$(CONFIG_GENERIC_ARCH_NUMA) += arch_numa.o
+obj-$(CONFIG_GENERIC_CPU_CACHE_INVALIDATE_MEMREGION) += cache.o
 obj-$(CONFIG_ACPI) += physical_location.o
 
 obj-y			+= test/

diff --git a/drivers/base/cache.c b/drivers/base/cache.c
new file mode 100644
index 000000000000..8d351657bbef
--- /dev/null
+++ b/drivers/base/cache.c

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic support for CPU Cache Invalidate Memregion
+ */
+
+#include <linux/spinlock.h>
+#include <linux/export.h>
+#include <asm/cacheflush.h>
+
+
+static const struct system_cache_flush_method *scfm_data;
+DEFINE_SPINLOCK(scfm_lock);