MIPS: Add support for PIC32MZDA platform

This adds support for the Microchip PIC32 MIPS microcontroller with the
specific variant PIC32MZDA. PIC32MZDA is based on the MIPS m14KEc core
and boots using device tree.

This includes an early pin setup and early clock setup needed prior to
device tree being initialized. In additon, an interface is provided to
synchronize access to registers shared across several peripherals.

Signed-off-by: Joshua Henderson <joshua.henderson@microchip.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12097/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/pic32/pic32mzda/init.c

@@ -0,0 +1,156 @@
+/*
+ * Joshua Henderson, joshua.henderson@microchip.com
+ * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.
+ *
+ *  This program is free software; you can distribute it and/or modify it
+ *  under the terms of the GNU General Public License (Version 2) as
+ *  published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/of_address.h>
+#include <linux/of_fdt.h>
+#include <linux/of_platform.h>
+#include <linux/platform_data/sdhci-pic32.h>
+
+#include <asm/fw/fw.h>
+#include <asm/mips-boards/generic.h>
+#include <asm/prom.h>
+
+#include "pic32mzda.h"
+
+const char *get_system_type(void)
+{
+	return "PIC32MZDA";
+}
+
+static ulong get_fdtaddr(void)
+{
+	ulong ftaddr = 0;
+
+	if ((fw_arg0 == -2) && fw_arg1 && !fw_arg2 && !fw_arg3)
+		return (ulong)fw_arg1;
+
+	if (__dtb_start < __dtb_end)
+		ftaddr = (ulong)__dtb_start;
+
+	return ftaddr;
+}
+
+void __init plat_mem_setup(void)
+{
+	void *dtb;
+
+	dtb = (void *)get_fdtaddr();
+	if (!dtb) {
+		pr_err("pic32: no DTB found.\n");
+		return;
+	}
+
+	/*
+	 * Load the builtin device tree. This causes the chosen node to be
+	 * parsed resulting in our memory appearing.
+	 */
+	__dt_setup_arch(dtb);
+
+	pr_info("Found following command lines\n");
+	pr_info(" boot_command_line: %s\n", boot_command_line);
+	pr_info(" arcs_cmdline     : %s\n", arcs_cmdline);
+#ifdef CONFIG_CMDLINE_BOOL
+	pr_info(" builtin_cmdline  : %s\n", CONFIG_CMDLINE);
+#endif
+	if (dtb != __dtb_start)
+		strlcpy(arcs_cmdline, boot_command_line, COMMAND_LINE_SIZE);
+
+#ifdef CONFIG_EARLY_PRINTK
+	fw_init_early_console(-1);
+#endif
+	pic32_config_init();
+}
+
+static __init void pic32_init_cmdline(int argc, char *argv[])
+{
+	unsigned int count = COMMAND_LINE_SIZE - 1;
+	int i;
+	char *dst = &(arcs_cmdline[0]);
+	char *src;
+
+	for (i = 1; i < argc && count; ++i) {
+		src = argv[i];
+		while (*src && count) {
+			*dst++ = *src++;
+			--count;
+		}
+		*dst++ = ' ';
+	}
+	if (i > 1)
+		--dst;
+
+	*dst = 0;
+}
+
+void __init prom_init(void)
+{
+	pic32_init_cmdline((int)fw_arg0, (char **)fw_arg1);
+}
+
+void __init prom_free_prom_memory(void)
+{
+}
+
+void __init device_tree_init(void)
+{
+	if (!initial_boot_params)
+		return;
+
+	unflatten_and_copy_device_tree();
+}
+
+static struct pic32_sdhci_platform_data sdhci_data = {
+	.setup_dma = pic32_set_sdhci_adma_fifo_threshold,
+};
+
+static struct of_dev_auxdata pic32_auxdata_lookup[] __initdata = {
+	OF_DEV_AUXDATA("microchip,pic32mzda-sdhci", 0, "sdhci", &sdhci_data),
+	{ /* sentinel */}
+};
+
+static int __init pic32_of_prepare_platform_data(struct of_dev_auxdata *lookup)
+{
+	struct device_node *root, *np;
+	struct resource res;
+
+	root = of_find_node_by_path("/");
+
+	for (; lookup->compatible; lookup++) {
+		np = of_find_compatible_node(NULL, NULL, lookup->compatible);
+		if (np) {
+			lookup->name = (char *)np->name;
+			if (lookup->phys_addr)
+				continue;
+			if (!of_address_to_resource(np, 0, &res))
+				lookup->phys_addr = res.start;
+		}
+	}
+
+	return 0;
+}
+
+static int __init plat_of_setup(void)
+{
+	if (!of_have_populated_dt())
+		panic("Device tree not present");
+
+	pic32_of_prepare_platform_data(pic32_auxdata_lookup);
+	if (of_platform_populate(NULL, of_default_bus_match_table,
+				 pic32_auxdata_lookup, NULL))
+		panic("Failed to populate DT");
+
+	return 0;
+}
+arch_initcall(plat_of_setup);