MIPS: Lantiq: Add initial support for Lantiq SoCs

Add initial support for Mips based SoCs made by Lantiq. This series will add
support for the XWAY family.

The series allows booting a minimal system using a initramfs or NOR. Missing
drivers and support for Amazon and GPON family will be provided in a later
series.

[Ralf: Remove some cargo cult programming and fixed formatting.]

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Ralph Hempel <ralph.hempel@lantiq.com>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2252/
Patchwork: https://patchwork.linux-mips.org/patch/2371/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 140 insertions, 0 deletions

diff --git a/arch/mips/lantiq/clk.c b/arch/mips/lantiq/clk.c
new file mode 100644
index 0000000..9456089
--- /dev/null
+++ b/arch/mips/lantiq/clk.c
@@ -0,0 +1,140 @@
+/*
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ * Copyright (C) 2010 Thomas Langer <thomas.langer@lantiq.com>
+ * Copyright (C) 2010 John Crispin <blogic@openwrt.org>
+ */
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/list.h>
+
+#include <asm/time.h>
+#include <asm/irq.h>
+#include <asm/div64.h>
+
+#include <lantiq_soc.h>
+
+#include "clk.h"
+
+struct clk {
+	const char *name;
+	unsigned long rate;
+	unsigned long (*get_rate) (void);
+};
+
+static struct clk *cpu_clk;
+static int cpu_clk_cnt;
+
+/* lantiq socs have 3 static clocks */
+static struct clk cpu_clk_generic[] = {
+	{
+		.name = "cpu",
+		.get_rate = ltq_get_cpu_hz,
+	}, {
+		.name = "fpi",
+		.get_rate = ltq_get_fpi_hz,
+	}, {
+		.name = "io",
+		.get_rate = ltq_get_io_region_clock,
+	},
+};
+
+static struct resource ltq_cgu_resource = {
+	.name	= "cgu",
+	.start	= LTQ_CGU_BASE_ADDR,
+	.end	= LTQ_CGU_BASE_ADDR + LTQ_CGU_SIZE - 1,
+	.flags	= IORESOURCE_MEM,
+};
+
+/* remapped clock register range */
+void __iomem *ltq_cgu_membase;
+
+void clk_init(void)
+{
+	cpu_clk = cpu_clk_generic;
+	cpu_clk_cnt = ARRAY_SIZE(cpu_clk_generic);
+}
+
+static inline int clk_good(struct clk *clk)
+{
+	return clk && !IS_ERR(clk);
+}
+
+unsigned long clk_get_rate(struct clk *clk)
+{
+	if (unlikely(!clk_good(clk)))
+		return 0;
+
+	if (clk->rate != 0)
+		return clk->rate;
+
+	if (clk->get_rate != NULL)
+		return clk->get_rate();
+
+	return 0;
+}
+EXPORT_SYMBOL(clk_get_rate);
+
+struct clk *clk_get(struct device *dev, const char *id)
+{
+	int i;
+
+	for (i = 0; i < cpu_clk_cnt; i++)
+		if (!strcmp(id, cpu_clk[i].name))
+			return &cpu_clk[i];
+	BUG();
+	return ERR_PTR(-ENOENT);
+}
+EXPORT_SYMBOL(clk_get);
+
+void clk_put(struct clk *clk)
+{
+	/* not used */
+}
+EXPORT_SYMBOL(clk_put);
+
+static inline u32 ltq_get_counter_resolution(void)
+{
+	u32 res;
+
+	__asm__ __volatile__(
+		".set   push\n"
+		".set   mips32r2\n"
+		"rdhwr  %0, $3\n"
+		".set pop\n"
+		: "=&r" (res)
+		: /* no input */
+		: "memory");
+
+	return res;
+}
+
+void __init plat_time_init(void)
+{
+	struct clk *clk;
+
+	if (insert_resource(&iomem_resource, &ltq_cgu_resource) < 0)
+		panic("Failed to insert cgu memory\n");
+
+	if (request_mem_region(ltq_cgu_resource.start,
+			resource_size(&ltq_cgu_resource), "cgu") < 0)
+		panic("Failed to request cgu memory\n");
+
+	ltq_cgu_membase = ioremap_nocache(ltq_cgu_resource.start,
+				resource_size(&ltq_cgu_resource));
+	if (!ltq_cgu_membase) {
+		pr_err("Failed to remap cgu memory\n");
+		unreachable();
+	}
+	clk = clk_get(0, "cpu");
+	mips_hpt_frequency = clk_get_rate(clk) / ltq_get_counter_resolution();
+	write_c0_compare(read_c0_count());
+	clk_put(clk);
+}