nds32: L2 cache support

This patch adds L2 cache support.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

arch/nds32/kernel/atl2c.c

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#include <linux/compiler.h>
+#include <linux/of_address.h>
+#include <linux/of_fdt.h>
+#include <linux/of_platform.h>
+#include <asm/l2_cache.h>
+
+void __iomem *atl2c_base;
+static const struct of_device_id atl2c_ids[] __initconst = {
+	{.compatible = "andestech,atl2c",}
+};
+
+static int __init atl2c_of_init(void)
+{
+	struct device_node *np;
+	struct resource res;
+	unsigned long tmp = 0;
+	unsigned long l2set, l2way, l2clsz;
+
+	if (!(__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskL2C))
+		return -ENODEV;
+
+	np = of_find_matching_node(NULL, atl2c_ids);
+	if (!np)
+		return -ENODEV;
+
+	if (of_address_to_resource(np, 0, &res))
+		return -ENODEV;
+
+	atl2c_base = ioremap(res.start, resource_size(&res));
+	if (!atl2c_base)
+		return -ENOMEM;
+
+	l2set =
+	    64 << ((L2C_R_REG(L2_CA_CONF_OFF) & L2_CA_CONF_mskL2SET) >>
+		   L2_CA_CONF_offL2SET);
+	l2way =
+	    1 +
+	    ((L2C_R_REG(L2_CA_CONF_OFF) & L2_CA_CONF_mskL2WAY) >>
+	     L2_CA_CONF_offL2WAY);
+	l2clsz =
+	    4 << ((L2C_R_REG(L2_CA_CONF_OFF) & L2_CA_CONF_mskL2CLSZ) >>
+		  L2_CA_CONF_offL2CLSZ);
+	pr_info("L2:%luKB/%luS/%luW/%luB\n",
+		l2set * l2way * l2clsz / 1024, l2set, l2way, l2clsz);
+
+	tmp = L2C_R_REG(L2CC_PROT_OFF);
+	tmp &= ~L2CC_PROT_mskMRWEN;
+	L2C_W_REG(L2CC_PROT_OFF, tmp);
+
+	tmp = L2C_R_REG(L2CC_SETUP_OFF);
+	tmp &= ~L2CC_SETUP_mskPART;
+	L2C_W_REG(L2CC_SETUP_OFF, tmp);
+
+	tmp = L2C_R_REG(L2CC_CTRL_OFF);
+	tmp |= L2CC_CTRL_mskEN;
+	L2C_W_REG(L2CC_CTRL_OFF, tmp);
+
+	return 0;
+}
+
+subsys_initcall(atl2c_of_init);