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: Max Filippov <jcmvbkbc@gmail.com>

2 files changed, 36 insertions, 2 deletions

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 81f57e8c8f1b..cb44f6f95968 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -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
diff --git a/arch/xtensa/include/asm/initialize_mmu.h b/arch/xtensa/include/asm/initialize_mmu.h
index cdac5584ec0c..e256f2270ec9 100644
--- a/arch/xtensa/include/asm/initialize_mmu.h
+++ b/arch/xtensa/include/asm/initialize_mmu.h
@@ -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__*/