arm: cpu: add basic arm64 mmu support

This commit adds basic mmu support, ie:
        - DMA cache handling is not supported
        - Remapping memory region also

The current mmu setting is:
        - 4KB granularity
        - 3 level lookup (skipping L0)
        - 33 bits per VA

This is based on coreboot and u-boot mmu configuration.

Signed-off-by: Raphael Poggi <poggi.raph@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 54 insertions, 0 deletions

diff --git a/arch/arm/cpu/mmu.h b/arch/arm/cpu/mmu.h
index 79ebc80d7d..186d408ead 100644
--- a/arch/arm/cpu/mmu.h
+++ b/arch/arm/cpu/mmu.h
@@ -1,6 +1,60 @@
 #ifndef __ARM_MMU_H
 #define __ARM_MMU_H
 
+#ifdef CONFIG_CPU_64v8
+
+#define TCR_FLAGS		(TCR_TG0_4K | \
+		TCR_SHARED_OUTER | \
+		TCR_SHARED_INNER | \
+		TCR_IRGN_WBWA | \
+		TCR_ORGN_WBWA | \
+		TCR_T0SZ(BITS_PER_VA))
+
+#ifndef __ASSEMBLY__
+
+static inline void set_ttbr_tcr_mair(int el, uint64_t table, uint64_t tcr, uint64_t attr)
+{
+	asm volatile("dsb sy");
+	if (el == 1) {
+		asm volatile("msr ttbr0_el1, %0" : : "r" (table) : "memory");
+		asm volatile("msr tcr_el1, %0" : : "r" (tcr) : "memory");
+		asm volatile("msr mair_el1, %0" : : "r" (attr) : "memory");
+	} else if (el == 2) {
+		asm volatile("msr ttbr0_el2, %0" : : "r" (table) : "memory");
+		asm volatile("msr tcr_el2, %0" : : "r" (tcr) : "memory");
+		asm volatile("msr mair_el2, %0" : : "r" (attr) : "memory");
+	} else if (el == 3) {
+		asm volatile("msr ttbr0_el3, %0" : : "r" (table) : "memory");
+		asm volatile("msr tcr_el3, %0" : : "r" (tcr) : "memory");
+		asm volatile("msr mair_el3, %0" : : "r" (attr) : "memory");
+	} else {
+		hang();
+	}
+	asm volatile("isb");
+}
+
+static inline uint64_t get_ttbr(int el)
+{
+	uint64_t val;
+	if (el == 1) {
+		asm volatile("mrs %0, ttbr0_el1" : "=r" (val));
+	} else if (el == 2) {
+		asm volatile("mrs %0, ttbr0_el2" : "=r" (val));
+	} else if (el == 3) {
+		asm volatile("mrs %0, ttbr0_el3" : "=r" (val));
+	} else {
+		hang();
+	}
+
+	return val;
+}
+
+void mmu_early_enable(uint64_t membase, uint64_t memsize, uint64_t _ttb);
+
+#endif
+
+#endif /* CONFIG_CPU_64v8 */
+
 #ifdef CONFIG_MMU
 void __mmu_cache_on(void);
 void __mmu_cache_off(void);