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Commit 2eabc180 authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: nommu: set up cache and atomctl in initialize_mmu 



initialize_mmu sets up atomctl SR which is needed for s32c1i to function
correctly even in noMMU configurations. It's also a good place to set up
caching attributes of physical memory.

Allow enabling INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX in noMMU
configurations for setting up atomctl and cache attributes.

Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent 53490121

arch/xtensa/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -191,7 +191,6 @@ config HOTPLUG_CPU 


config INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX

	bool "Initialize Xtensa MMU inside the Linux kernel code"

	depends on MMU

	default y

	help

	  Earlier version initialized the MMU in the exception vector

arch/xtensa/include/asm/initialize_mmu.h

+36 −1
Original line number Diff line number Diff line
@@ -26,8 +26,16 @@ 
#include <asm/pgtable.h>

#include <asm/vectors.h>



#if XCHAL_HAVE_PTP_MMU

#define CA_BYPASS	(_PAGE_CA_BYPASS | _PAGE_HW_WRITE | _PAGE_HW_EXEC)

#define CA_WRITEBACK	(_PAGE_CA_WB     | _PAGE_HW_WRITE | _PAGE_HW_EXEC)

#else

#define CA_WRITEBACK	(0x4)

#endif



#ifndef XCHAL_SPANNING_WAY

#define XCHAL_SPANNING_WAY 0

#endif



#ifdef __ASSEMBLY__
@@ -75,7 +83,7 @@ 


	/* Step 1: invalidate mapping at 0x40000000..0x5FFFFFFF. */



	movi	a2, 0x40000006

	movi	a2, 0x40000000 | XCHAL_SPANNING_WAY

	idtlb	a2

	iitlb	a2

	isync
@@ -153,6 +161,33 @@ 
#endif /* defined(CONFIG_MMU) && XCHAL_HAVE_PTP_MMU &&

	  XCHAL_HAVE_SPANNING_WAY */



#if !defined(CONFIG_MMU) && XCHAL_HAVE_TLBS

	/* Enable data and instruction cache in the DEFAULT_MEMORY region

	 * if the processor has DTLB and ITLB.

	 */



	movi	a5, PLATFORM_DEFAULT_MEM_START | XCHAL_SPANNING_WAY

	movi	a6, ~_PAGE_ATTRIB_MASK

	movi	a7, CA_WRITEBACK

	movi	a8, 0x20000000

	movi	a9, PLATFORM_DEFAULT_MEM_SIZE

	j	2f

1:

	sub	a9, a9, a8

2:

	rdtlb1	a3, a5

	ritlb1	a4, a5

	and	a3, a3, a6

	and	a4, a4, a6

	or	a3, a3, a7

	or	a4, a4, a7

	wdtlb	a3, a5

	witlb	a4, a5

	add	a5, a5, a8

	bltu	a8, a9, 1b



#endif



	.endm



#endif /*__ASSEMBLY__*/