bcm47xx: add support for kernel 5.4

Ethernet, switch, LEDs, buttons, USB, sysupgrade & LuCI were
successfully tested on BCM4706.

WARNING: Hack for BCM4710 adding BCM4710_PROTECTED_FILL_TLB() to the
local_r4k_flush_cache_sigtramp() could not be ported. That function has
been dropped in:
commit adcc81f148d7 ("MIPS: math-emu: Write-protect delay slot emulation pages")
commit 3315b6b336c8 ("MIPS: Delete unused flush_cache_sigtramp()")
it's unsure if that chipset will still work reliably.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

1 files changed, 74 insertions, 0 deletions

diff --git a/target/linux/bcm47xx/patches-5.4/310-no_highpage.patch b/target/linux/bcm47xx/patches-5.4/310-no_highpage.patch
new file mode 100644
index 0000000000..4eea60617d
--- /dev/null
+++ b/target/linux/bcm47xx/patches-5.4/310-no_highpage.patch
@@ -0,0 +1,74 @@
+From: Jeff Hansen <jhansen@cardaccess-inc.com>
+Subject: [PATCH] no highpage
+
+On ASUS WL-500gP there are many unexpected "Segmentation fault"s that
+seem to be caused by a kernel. They can be avoided by:
+1) Disabling highpage
+2) Using flush_cache_mm in flush_cache_dup_mm
+
+For details see OpenWrt ticket #2035 https://dev.openwrt.org/ticket/2035
+---
+--- a/arch/mips/include/asm/page.h
++++ b/arch/mips/include/asm/page.h
+@@ -71,6 +71,7 @@ static inline unsigned int page_size_ftl
+ #endif /* CONFIG_MIPS_HUGE_TLB_SUPPORT */
+ 
+ #include <linux/pfn.h>
++#include <asm/cpu-features.h>
+ 
+ extern void build_clear_page(void);
+ extern void build_copy_page(void);
+@@ -110,11 +111,16 @@ static inline void clear_user_page(void
+ 		flush_data_cache_page((unsigned long)addr);
+ }
+ 
+-struct vm_area_struct;
+-extern void copy_user_highpage(struct page *to, struct page *from,
+-	unsigned long vaddr, struct vm_area_struct *vma);
++static inline void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
++	struct page *to)
++{
++	extern void (*flush_data_cache_page)(unsigned long addr);
+ 
+-#define __HAVE_ARCH_COPY_USER_HIGHPAGE
++	copy_page(vto, vfrom);
++	if (!cpu_has_ic_fills_f_dc ||
++	    pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
++		flush_data_cache_page((unsigned long)vto);
++}
+ 
+ /*
+  * These are used to make use of C type-checking..
+--- a/arch/mips/mm/init.c
++++ b/arch/mips/mm/init.c
+@@ -168,30 +168,6 @@ void kunmap_coherent(void)
+ 	preempt_enable();
+ }
+ 
+-void copy_user_highpage(struct page *to, struct page *from,
+-	unsigned long vaddr, struct vm_area_struct *vma)
+-{
+-	void *vfrom, *vto;
+-
+-	vto = kmap_atomic(to);
+-	if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
+-	    page_mapcount(from) && !Page_dcache_dirty(from)) {
+-		vfrom = kmap_coherent(from, vaddr);
+-		copy_page(vto, vfrom);
+-		kunmap_coherent();
+-	} else {
+-		vfrom = kmap_atomic(from);
+-		copy_page(vto, vfrom);
+-		kunmap_atomic(vfrom);
+-	}
+-	if ((!cpu_has_ic_fills_f_dc) ||
+-	    pages_do_alias((unsigned long)vto, vaddr & PAGE_MASK))
+-		flush_data_cache_page((unsigned long)vto);
+-	kunmap_atomic(vto);
+-	/* Make sure this page is cleared on other CPU's too before using it */
+-	smp_wmb();
+-}
+-
+ void copy_to_user_page(struct vm_area_struct *vma,
+ 	struct page *page, unsigned long vaddr, void *dst, const void *src,
+ 	unsigned long len)