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authorMax Filippov <jcmvbkbc@gmail.com>2018-08-12 06:01:40 -0700
committerMax Filippov <jcmvbkbc@gmail.com>2018-08-13 20:08:19 -0700
commit7bb516ca5424e12b42124fab2906b6da9c81ba9c (patch)
tree275dd23356eba62a81025221e23df3210a87a7be /arch/xtensa
parentfec3259c9f747c039f90e99570540114c8d81a14 (diff)
downloadlinux-7bb516ca5424e12b42124fab2906b6da9c81ba9c.tar.bz2
xtensa: rework noMMU cache attributes initialization
Marking default memory region as cached is not always sufficient and is not flexible. Allow specifying cache attributes for the whole memory address space with new config entry MEMMAP_CACHEATTR. Apply it after cache initialization. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa')
-rw-r--r--arch/xtensa/Kconfig17
-rw-r--r--arch/xtensa/configs/nommu_kc705_defconfig1
-rw-r--r--arch/xtensa/include/asm/initialize_mmu.h42
-rw-r--r--arch/xtensa/kernel/head.S2
4 files changed, 41 insertions, 21 deletions
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index d575e8701955..524b80722fd0 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -249,6 +249,23 @@ config INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
If in doubt, say Y.
+config MEMMAP_CACHEATTR
+ hex "Cache attributes for the memory address space"
+ depends on !MMU
+ default 0x22222222
+ help
+ These cache attributes are set up for noMMU systems. Each hex digit
+ specifies cache attributes for the corresponding 512MB memory
+ 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).
+
config KSEG_PADDR
hex "Physical address of the KSEG mapping"
depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX && MMU
diff --git a/arch/xtensa/configs/nommu_kc705_defconfig b/arch/xtensa/configs/nommu_kc705_defconfig
index 624f9b3a3878..610f622d3c84 100644
--- a/arch/xtensa/configs/nommu_kc705_defconfig
+++ b/arch/xtensa/configs/nommu_kc705_defconfig
@@ -33,6 +33,7 @@ CONFIG_XTENSA_VARIANT_CUSTOM_NAME="de212"
# CONFIG_XTENSA_VARIANT_MMU is not set
CONFIG_XTENSA_UNALIGNED_USER=y
CONFIG_PREEMPT=y
+CONFIG_MEMMAP_CACHEATTR=0xfff2442f
# CONFIG_PCI is not set
CONFIG_XTENSA_PLATFORM_XTFPGA=y
CONFIG_CMDLINE_BOOL=y
diff --git a/arch/xtensa/include/asm/initialize_mmu.h b/arch/xtensa/include/asm/initialize_mmu.h
index 42410f253597..10e9852b2fb4 100644
--- a/arch/xtensa/include/asm/initialize_mmu.h
+++ b/arch/xtensa/include/asm/initialize_mmu.h
@@ -177,36 +177,36 @@
#endif /* defined(CONFIG_MMU) && XCHAL_HAVE_PTP_MMU &&
XCHAL_HAVE_SPANNING_WAY */
-#if !defined(CONFIG_MMU) && XCHAL_HAVE_TLBS && \
- (XCHAL_DCACHE_SIZE || XCHAL_ICACHE_SIZE)
- /* Enable data and instruction cache in the DEFAULT_MEMORY region
- * if the processor has DTLB and ITLB.
- */
+ .endm
+
+ .macro initialize_cacheattr
- movi a5, PLATFORM_DEFAULT_MEM_START | XCHAL_SPANNING_WAY
+#if !defined(CONFIG_MMU) && XCHAL_HAVE_TLBS
+#if CONFIG_MEMMAP_CACHEATTR == 0x22222222 && XCHAL_HAVE_PTP_MMU
+#error Default MEMMAP_CACHEATTR of 0x22222222 does not work with full MMU.
+#endif
+
+ movi a5, XCHAL_SPANNING_WAY
movi a6, ~_PAGE_ATTRIB_MASK
- movi a7, CA_WRITEBACK
+ movi a4, CONFIG_MEMMAP_CACHEATTR
movi a8, 0x20000000
- movi a9, PLATFORM_DEFAULT_MEM_SIZE
- j 2f
1:
- sub a9, a9, a8
-2:
-#if XCHAL_DCACHE_SIZE
rdtlb1 a3, a5
+ xor a3, a3, a4
and a3, a3, a6
- or a3, a3, a7
+ xor a3, a3, a4
wdtlb a3, a5
-#endif
-#if XCHAL_ICACHE_SIZE
- ritlb1 a4, a5
- and a4, a4, a6
- or a4, a4, a7
- witlb a4, a5
-#endif
+ ritlb1 a3, a5
+ xor a3, a3, a4
+ and a3, a3, a6
+ xor a3, a3, a4
+ witlb a3, a5
+
add a5, a5, a8
- bltu a8, a9, 1b
+ srli a4, a4, 4
+ bgeu a5, a8, 1b
+ isync
#endif
.endm
diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S
index 9c4e9433e536..2f76118ecf62 100644
--- a/arch/xtensa/kernel/head.S
+++ b/arch/xtensa/kernel/head.S
@@ -181,6 +181,8 @@ ENTRY(_startup)
isync
+ initialize_cacheattr
+
#ifdef CONFIG_HAVE_SMP
movi a2, CCON # MX External Register to Configure Cache
movi a3, 1