xtensa: implement initialize_cacheattr for MPU cores

Use CONFIG_MEMMAP_CACHEATTR to initialize MPU as described in the Xtensa
LSP RM document. Coalesce adjacent regions with the same cacheattr.
Update Kconfig help text.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 4b9aafe..f081751 100644 (file)
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -256,12 +256,26 @@ config MEMMAP_CACHEATTR
          region: bits 0..3 -- for addresses 0x00000000..0x1fffffff,
          bits 4..7 -- for addresses 0x20000000..0x3fffffff, and so on.
 
-         Cache attribute values are specific for the MMU type, so e.g.
-         for region protection MMUs: 2 is cache bypass, 4 is WB cached,
-         1 is WT cached, f is illegal. For ful MMU: bit 0 makes it executable,
-         bit 1 makes it writable, bits 2..3 meaning is 0: cache bypass,
-         1: WB cache, 2: WT cache, 3: special (c and e are illegal, f is
-         reserved).
+         Cache attribute values are specific for the MMU type.
+         For region protection MMUs:
+           1: WT cached,
+           2: cache bypass,
+           4: WB cached,
+           f: illegal.
+         For ful MMU:
+           bit 0: executable,
+           bit 1: writable,
+           bits 2..3:
+             0: cache bypass,
+             1: WB cache,
+             2: WT cache,
+             3: special (c and e are illegal, f is reserved).
+         For MPU:
+           0: illegal,
+           1: WB cache,
+           2: WB, no-write-allocate cache,
+           3: WT cache,
+           4: cache bypass.
 
 config KSEG_PADDR
        hex "Physical address of the KSEG mapping"

diff --git a/arch/xtensa/include/asm/core.h b/arch/xtensa/include/asm/core.h
index ee02e16..5b4acb7 100644 (file)
--- a/arch/xtensa/include/asm/core.h
+++ b/arch/xtensa/include/asm/core.h
@@ -10,6 +10,10 @@
 #define XCHAL_HAVE_EXCLUSIVE 0
 #endif
 
+#ifndef XCHAL_HAVE_MPU
+#define XCHAL_HAVE_MPU 0
+#endif
+
 #ifndef XCHAL_SPANNING_WAY
 #define XCHAL_SPANNING_WAY 0
 #endif

diff --git a/arch/xtensa/include/asm/initialize_mmu.h b/arch/xtensa/include/asm/initialize_mmu.h
index d719785..323d057 100644 (file)
--- a/arch/xtensa/include/asm/initialize_mmu.h
+++ b/arch/xtensa/include/asm/initialize_mmu.h
@@ -177,11 +177,42 @@
 
        .macro  initialize_cacheattr
 
-#if !defined(CONFIG_MMU) && XCHAL_HAVE_TLBS
+#if !defined(CONFIG_MMU) && (XCHAL_HAVE_TLBS || XCHAL_HAVE_MPU)
 #if CONFIG_MEMMAP_CACHEATTR == 0x22222222 && XCHAL_HAVE_PTP_MMU
 #error Default MEMMAP_CACHEATTR of 0x22222222 does not work with full MMU.
 #endif
 
+#if XCHAL_HAVE_MPU
+       .data
+       .align  4
+.Lattribute_table:
+       .long 0x000000, 0x1fff00, 0x1ddf00, 0x1eef00
+       .long 0x006600, 0x000000, 0x000000, 0x000000
+       .long 0x000000, 0x000000, 0x000000, 0x000000
+       .long 0x000000, 0x000000, 0x000000, 0x000000
+       .previous
+
+       movi    a3, .Lattribute_table
+       movi    a4, CONFIG_MEMMAP_CACHEATTR
+       movi    a5, 1
+       movi    a6, XCHAL_MPU_ENTRIES
+       movi    a10, 0x20000000
+       movi    a11, -1
+1:
+       sub     a5, a5, a10
+       extui   a8, a4, 28, 4
+       beq     a8, a11, 2f
+       addi    a6, a6, -1
+       mov     a11, a8
+2:
+       addx4   a9, a8, a3
+       l32i    a9, a9, 0
+       or      a9, a9, a6
+       wptlb   a9, a5
+       slli    a4, a4, 4
+       bgeu    a5, a10, 1b
+
+#else
        movi    a5, XCHAL_SPANNING_WAY
        movi    a6, ~_PAGE_ATTRIB_MASK
        movi    a4, CONFIG_MEMMAP_CACHEATTR
@@ -204,6 +235,7 @@
 
        isync
 #endif
+#endif
 
        .endm