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-rw-r--r--arch/arm64/include/asm/cache.h40
1 files changed, 40 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
index 5ee5bca8c24b..13dd42c3ad4e 100644
--- a/arch/arm64/include/asm/cache.h
+++ b/arch/arm64/include/asm/cache.h
@@ -40,6 +40,15 @@
#define L1_CACHE_SHIFT (6)
#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
+
+#define CLIDR_LOUU_SHIFT 27
+#define CLIDR_LOC_SHIFT 24
+#define CLIDR_LOUIS_SHIFT 21
+
+#define CLIDR_LOUU(clidr) (((clidr) >> CLIDR_LOUU_SHIFT) & 0x7)
+#define CLIDR_LOC(clidr) (((clidr) >> CLIDR_LOC_SHIFT) & 0x7)
+#define CLIDR_LOUIS(clidr) (((clidr) >> CLIDR_LOUIS_SHIFT) & 0x7)
+
/*
* Memory returned by kmalloc() may be used for DMA, so we must make
* sure that all such allocations are cache aligned. Otherwise,
@@ -84,6 +93,37 @@ static inline int cache_line_size(void)
return cwg ? 4 << cwg : ARCH_DMA_MINALIGN;
}
+/*
+ * Read the effective value of CTR_EL0.
+ *
+ * According to ARM ARM for ARMv8-A (ARM DDI 0487C.a),
+ * section D10.2.33 "CTR_EL0, Cache Type Register" :
+ *
+ * CTR_EL0.IDC reports the data cache clean requirements for
+ * instruction to data coherence.
+ *
+ * 0 - dcache clean to PoU is required unless :
+ * (CLIDR_EL1.LoC == 0) || (CLIDR_EL1.LoUIS == 0 && CLIDR_EL1.LoUU == 0)
+ * 1 - dcache clean to PoU is not required for i-to-d coherence.
+ *
+ * This routine provides the CTR_EL0 with the IDC field updated to the
+ * effective state.
+ */
+static inline u32 __attribute_const__ read_cpuid_effective_cachetype(void)
+{
+ u32 ctr = read_cpuid_cachetype();
+
+ if (!(ctr & BIT(CTR_IDC_SHIFT))) {
+ u64 clidr = read_sysreg(clidr_el1);
+
+ if (CLIDR_LOC(clidr) == 0 ||
+ (CLIDR_LOUIS(clidr) == 0 && CLIDR_LOUU(clidr) == 0))
+ ctr |= BIT(CTR_IDC_SHIFT);
+ }
+
+ return ctr;
+}
+
#endif /* __ASSEMBLY__ */
#endif