1 files changed, 78 insertions, 0 deletions
diff --git a/arch/avr32/cpu/at32ap700x/mmu.c b/arch/avr32/cpu/at32ap700x/mmu.c
new file mode 100644
index 0000000..0e28b21
--- /dev/null
+++ b/arch/avr32/cpu/at32ap700x/mmu.c
@@ -0,0 +1,78 @@
+#include <common.h>
+#include <asm/arch/mmu.h>
+#include <asm/sysreg.h>
+
+void mmu_init_r(unsigned long dest_addr)
+{
+	uintptr_t	vmr_table_addr;
+
+	/* Round monitor address down to the nearest page boundary */
+	dest_addr &= PAGE_ADDR_MASK;
+
+	/* Initialize TLB entry 0 to cover the monitor, and lock it */
+	sysreg_write(TLBEHI, dest_addr | SYSREG_BIT(TLBEHI_V));
+	sysreg_write(TLBELO, dest_addr | MMU_VMR_CACHE_WRBACK);
+	sysreg_write(MMUCR, SYSREG_BF(DRP, 0) | SYSREG_BF(DLA, 1)
+			| SYSREG_BIT(MMUCR_S) | SYSREG_BIT(M));
+	__builtin_tlbw();
+
+	/*
+	 * Calculate the address of the VM range table in a PC-relative
+	 * manner to make sure we hit the SDRAM and not the flash.
+	 */
+	vmr_table_addr = (uintptr_t)&mmu_vmr_table;
+	sysreg_write(PTBR, vmr_table_addr);
+	printf("VMR table @ 0x%08lx\n", vmr_table_addr);
+
+	/* Enable paging */
+	sysreg_write(MMUCR, SYSREG_BF(DRP, 1) | SYSREG_BF(DLA, 1)
+			| SYSREG_BIT(MMUCR_S) | SYSREG_BIT(M) | SYSREG_BIT(E));
+}
+
+int mmu_handle_tlb_miss(void)
+{
+	const struct mmu_vm_range *vmr_table;
+	const struct mmu_vm_range *vmr;
+	unsigned int fault_pgno;
+	int first, last;
+
+	fault_pgno = sysreg_read(TLBEAR) >> PAGE_SHIFT;
+	vmr_table = (const struct mmu_vm_range *)sysreg_read(PTBR);
+
+	/* Do a binary search through the VM ranges */
+	first = 0;
+	last = CONFIG_SYS_NR_VM_REGIONS;
+	while (first < last) {
+		unsigned int start;
+		int middle;
+
+		/* Pick the entry in the middle of the remaining range */
+		middle = (first + last) >> 1;
+		vmr = &vmr_table[middle];
+		start = vmr->virt_pgno;
+
+		/* Do the bisection thing */
+		if (fault_pgno < start) {
+			last = middle;
+		} else if (fault_pgno >= (start + vmr->nr_pages)) {
+			first = middle + 1;
+		} else {
+			/* Got it; let's slam it into the TLB */
+			uint32_t tlbelo;
+
+			tlbelo = vmr->phys & ~PAGE_ADDR_MASK;
+			tlbelo |= fault_pgno << PAGE_SHIFT;
+			sysreg_write(TLBELO, tlbelo);
+			__builtin_tlbw();
+
+			/* Zero means success */
+			return 0;
+		}
+	}
+
+	/*
+	 * Didn't find any matching entries. Return a nonzero value to
+	 * indicate that this should be treated as a fatal exception.
+	 */
+	return -1;
+}