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, 78 insertions, 0 deletions

diff --git a/target/linux/bcm47xx/patches-5.4/160-kmap_coherent.patch b/target/linux/bcm47xx/patches-5.4/160-kmap_coherent.patch
new file mode 100644
index 0000000000..55e99dbddd
--- /dev/null
+++ b/target/linux/bcm47xx/patches-5.4/160-kmap_coherent.patch
@@ -0,0 +1,78 @@
+From: Jeff Hansen <jhansen@cardaccess-inc.com>
+Subject: [PATCH] kmap_coherent
+
+On ASUS WL-500gP there are some "Data bus error"s when executing simple
+commands liks "ps" or "cat /proc/1/cmdline".
+
+This fixes OpenWrt ticket #1485: https://dev.openwrt.org/ticket/1485
+---
+--- a/arch/mips/include/asm/cpu-features.h
++++ b/arch/mips/include/asm/cpu-features.h
+@@ -243,6 +243,9 @@
+ #ifndef cpu_has_pindexed_dcache
+ #define cpu_has_pindexed_dcache	(cpu_data[0].dcache.flags & MIPS_CACHE_PINDEX)
+ #endif
++#ifndef cpu_use_kmap_coherent
++#define cpu_use_kmap_coherent 1
++#endif
+ 
+ /*
+  * I-Cache snoops remote store.	 This only matters on SMP.  Some multiprocessors
+--- a/arch/mips/include/asm/mach-bcm47xx/cpu-feature-overrides.h
++++ b/arch/mips/include/asm/mach-bcm47xx/cpu-feature-overrides.h
+@@ -80,4 +80,6 @@
+ #define cpu_scache_line_size()		0
+ #define cpu_has_vz			0
+ 
++#define cpu_use_kmap_coherent		0
++
+ #endif /* __ASM_MACH_BCM47XX_CPU_FEATURE_OVERRIDES_H */
+--- a/arch/mips/mm/c-r4k.c
++++ b/arch/mips/mm/c-r4k.c
+@@ -697,7 +697,7 @@ static inline void local_r4k_flush_cache
+ 		map_coherent = (cpu_has_dc_aliases &&
+ 				page_mapcount(page) &&
+ 				!Page_dcache_dirty(page));
+-		if (map_coherent)
++		if (map_coherent && cpu_use_kmap_coherent)
+ 			vaddr = kmap_coherent(page, addr);
+ 		else
+ 			vaddr = kmap_atomic(page);
+@@ -719,7 +719,7 @@ static inline void local_r4k_flush_cache
+ 	}
+ 
+ 	if (vaddr) {
+-		if (map_coherent)
++		if (map_coherent && cpu_use_kmap_coherent)
+ 			kunmap_coherent();
+ 		else
+ 			kunmap_atomic(vaddr);
+--- a/arch/mips/mm/init.c
++++ b/arch/mips/mm/init.c
+@@ -174,7 +174,7 @@ void copy_user_highpage(struct page *to,
+ 	void *vfrom, *vto;
+ 
+ 	vto = kmap_atomic(to);
+-	if (cpu_has_dc_aliases &&
++	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);
+@@ -196,7 +196,7 @@ void copy_to_user_page(struct vm_area_st
+ 	struct page *page, unsigned long vaddr, void *dst, const void *src,
+ 	unsigned long len)
+ {
+-	if (cpu_has_dc_aliases &&
++	if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
+ 	    page_mapcount(page) && !Page_dcache_dirty(page)) {
+ 		void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
+ 		memcpy(vto, src, len);
+@@ -214,7 +214,7 @@ void copy_from_user_page(struct vm_area_
+ 	struct page *page, unsigned long vaddr, void *dst, const void *src,
+ 	unsigned long len)
+ {
+-	if (cpu_has_dc_aliases &&
++	if (cpu_has_dc_aliases && cpu_use_kmap_coherent &&
+ 	    page_mapcount(page) && !Page_dcache_dirty(page)) {
+ 		void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
+ 		memcpy(dst, vfrom, len);