bcm53xx: add testing support for kernel 5.10

It still requires fixing PCIe support:
[    6.644699] pcie_iproc_bcma bcma0:7: host bridge /axi@18000000/pcie@12000 ranges:
[    6.652217] pcie_iproc_bcma bcma0:7:   No bus range found for /axi@18000000/pcie@12000, using [bus 00-ff]
[    6.661833] OF: /axi@18000000/pcie@12000: Missing device_type
[    6.667622] pcie_iproc_bcma: probe of bcma0:7 failed with error -12
[    6.673985] pcie_iproc_bcma bcma0:8: host bridge /axi@18000000/pcie@13000 ranges:
[    6.681514] pcie_iproc_bcma bcma0:8:   No bus range found for /axi@18000000/pcie@13000, using [bus 00-ff]
[    6.691137] pcie_iproc_bcma: probe of bcma0:8 failed with error -12
[    6.697522] pcie_iproc_bcma bcma0:9: host bridge /axi@18000000/pcie@14000 ranges:
[    6.705048] pcie_iproc_bcma bcma0:9:   No bus range found for /axi@18000000/pcie@14000, using [bus 00-ff]
[    6.714669] pcie_iproc_bcma: probe of bcma0:9 failed with error -12

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

1 files changed, 101 insertions, 0 deletions

diff --git a/target/linux/bcm53xx/patches-5.10/300-ARM-BCM5301X-Disable-MMU-and-Dcache-during-decompres.patch b/target/linux/bcm53xx/patches-5.10/300-ARM-BCM5301X-Disable-MMU-and-Dcache-during-decompres.patch
new file mode 100644
index 0000000000..034d5b52fc
--- /dev/null
+++ b/target/linux/bcm53xx/patches-5.10/300-ARM-BCM5301X-Disable-MMU-and-Dcache-during-decompres.patch
@@ -0,0 +1,101 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Wed, 24 Sep 2014 22:14:07 +0200
+Subject: [PATCH] ARM: BCM5301X: Disable MMU and Dcache during decompression
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Broadcom devices have broken CFE (bootloader) that leaves hardware in an
+invalid state. It causes problems with booting Linux. On Northstar
+devices kernel was randomly hanging in ~25% of tries during early init.
+Hangs used to happen at random places in the start_kernel. On BCM53573
+kernel doesn't even seem to start booting.
+
+To workaround this problem we need to do following very early:
+1) Clear 2 following bits in the SCTLR register:
+#define CR_M    (1 << 0)        /* MMU enable */
+#define CR_C    (1 << 2)        /* Dcache enable */
+2) Flush the whole D-cache
+3) Disable L2 cache
+
+Unfortunately this patch is not upstreamable as it does above things
+unconditionally. We can't check if we are running on Broadcom platform
+in any safe way and doing such hacks with ARCH_MULTI_V7 is unacceptable
+as it could break other devices support.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+
+--- a/arch/arm/boot/compressed/Makefile
++++ b/arch/arm/boot/compressed/Makefile
+@@ -35,6 +35,11 @@ ifeq ($(CONFIG_ARCH_ACORN),y)
+ OBJS		+= ll_char_wr.o font.o
+ endif
+ 
++ifeq ($(CONFIG_ARCH_BCM_5301X),y)
++OBJS		+= head-bcm_5301x-mpcore.o
++OBJS		+= cache-v7-min.o
++endif
++
+ ifeq ($(CONFIG_ARCH_SA1100),y)
+ OBJS		+= head-sa1100.o
+ endif
+--- /dev/null
++++ b/arch/arm/boot/compressed/head-bcm_5301x-mpcore.S
+@@ -0,0 +1,37 @@
++/*
++ *
++ * Platform specific tweaks.  This is merged into head.S by the linker.
++ *
++ */
++
++#include <linux/linkage.h>
++#include <asm/assembler.h>
++#include <asm/cp15.h>
++
++		.section        ".start", "ax"
++
++/*
++ * This code section is spliced into the head code by the linker
++ */
++
++__plat_uncompress_start:
++
++	@ Preserve r8/r7 i.e. kernel entry values
++	mov	r12, r8
++
++	@ Clear MMU enable and Dcache enable bits
++	mrc	p15, 0, r0, c1, c0, 0		@ Read SCTLR
++	bic	r0, #CR_C|CR_M
++	mcr	p15, 0, r0, c1, c0, 0		@ Write SCTLR
++	nop
++
++	@ Call the cache invalidation routine
++	bl	v7_flush_dcache_all
++	nop
++	mov	r0,#0
++	ldr	r3, =0x19022000			@ L2 cache controller, control reg
++	str	r0, [r3, #0x100]		@ Disable L2 cache
++	nop
++
++	@ Restore
++	mov	r8, r12
+--- a/arch/arm/boot/compressed/cache-v7-min.S
++++ b/arch/arm/boot/compressed/cache-v7-min.S
+@@ -12,6 +12,7 @@
+ 
+ #include <linux/linkage.h>
+ #include <linux/init.h>
++#include <asm/assembler.h>
+ 
+ 	__INIT
+ 
+@@ -63,7 +64,7 @@ loop2:
+  ARM(	orr	r11, r11, r9, lsl r2	)	@ factor index number into r11
+  THUMB(	lsl	r6, r9, r2		)
+  THUMB(	orr	r11, r11, r6		)	@ factor index number into r11
+-	mcr	p15, 0, r11, c7, c14, 2		@ clean & invalidate by set/way
++	mcr     p15, 0, r11, c7, c6, 2		@ clean & invalidate by set/way
+ 	subs	r9, r9, #1			@ decrement the index
+ 	bge	loop2
+ 	subs	r4, r4, #1			@ decrement the way