socfpga: arria10: Allow dcache_enable before relocation

Before relocating to SDRAM, the ECC is initialized by clearing the
whole SDRAM. In order to speed this up, dcache_enable is used (see
sdram_init_ecc_bits).

Since commit 503eea451903 ("arm: cp15: update DACR value to activate
access control"), this no longer works, because running code in OCRAM
with the XN bit set causes a page fault. Override dram_bank_mmu_setup
to disable XN in the OCRAM and setup DRAM dcache before relocation.

Signed-off-by: Paweł Anikiel <pan@semihalf.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/mach-socfpga/misc_arria10.c

@@ -246,3 +246,29 @@ int qspi_flash_software_reset(void)
 	return 0;
 }
 #endif
+
+void dram_bank_mmu_setup(int bank)
+{
+	struct bd_info *bd = gd->bd;
+	u32 start, size;
+	int i;
+
+	/* If we're still in OCRAM, don't set the XN bit on it */
+	if (!(gd->flags & GD_FLG_RELOC)) {
+		set_section_dcache(
+			CONFIG_SYS_INIT_RAM_ADDR >> MMU_SECTION_SHIFT,
+			DCACHE_WRITETHROUGH);
+	}
+
+	/*
+	 * The default implementation of this function allows the DRAM dcache
+	 * to be enabled only after relocation. However, to speed up ECC
+	 * initialization, we want to be able to enable DRAM dcache before
+	 * relocation, so we don't check GD_FLG_RELOC (this assumes bd->bi_dram
+	 * is set first).
+	 */
+	start = bd->bi_dram[bank].start >> MMU_SECTION_SHIFT;
+	size = bd->bi_dram[bank].size >> MMU_SECTION_SHIFT;
+	for (i = start; i < start + size; i++)
+		set_section_dcache(i, DCACHE_DEFAULT_OPTION);
+}