Changes between Version 5 and Version 8 of Ticket #19312

Ticket #19312 – Description

-              v5
+              v8
 obvious fix:[[BR]]
 => replace use of ioremap_nocache() with ioremap_cache()
+Edit:
+ioremap_cache() is uncached by default since a long time.
+all 5.X kernels down to version 5.0
+all 4.X kernels down to version 4.0
+all 3.X kernels down to version 3.0
+from version 2.6.25 onwards we know for sure
+that ioremap_cache() has uncached semantics by default.
+[https://elixir.bootlin.com/linux/v2.6.25/source/include/asm-x86/io_64.h#L161][[BR]]
+{{{
+ * This one maps high address device memory and turns off caching for that area.
+ * it's useful if some control registers are in such an area and write combining
+ * or read caching is not desirable:
+ */
+extern void __iomem *ioremap_nocache(resource_size_t offset, unsigned long size);
+extern void __iomem *ioremap_cache(resource_size_t offset, unsigned long size);
+/*
+ * The default ioremap() behavior is non-cached:
+ */
+static inline void __iomem *ioremap(resource_size_t offset, unsigned long size)
+{
+        return ioremap_nocache(offset, size);
+}
+}}}
+That means we can and should replace ioremap_nocache() usage
+with ioremap_cache() and make kernel version 2.6.25 the tipping
+point for this.