Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

Pull MIPS updates from Ralf Baechle:
 "Boston platform support:
   - Document DT bindings
   - Add CLK driver for board clocks

  CM:
   - Avoid per-core locking with CM3 & higher
   - WARN on attempt to lock invalid VP, not BUG

  CPS:
   - Select CONFIG_SYS_SUPPORTS_SCHED_SMT for MIPSr6
   - Prevent multi-core with dcache aliasing
   - Handle cores not powering down more gracefully
   - Handle spurious VP starts more gracefully

  DSP:
   - Add lwx & lhx missaligned access support

  eBPF:
   - Add MIPS support along with many supporting change to add the
     required infrastructure

  Generic arch code:
   - Misc sysmips MIPS_ATOMIC_SET fixes
   - Drop duplicate HAVE_SYSCALL_TRACEPOINTS
   - Negate error syscall return in trace
   - Correct forced syscall errors
   - Traced negative syscalls should return -ENOSYS
   - Allow samples/bpf/tracex5 to access syscall arguments for sane
     traces
   - Cleanup from old Kconfig options in defconfigs
   - Fix PREF instruction usage by memcpy for MIPS R6
   - Fix various special cases in the FPU eulation
   - Fix some special cases in MIPS16e2 support
   - Fix MIPS I ISA /proc/cpuinfo reporting
   - Sort MIPS Kconfig alphabetically
   - Fix minimum alignment requirement of IRQ stack as required by
     ABI / GCC
   - Fix special cases in the module loader
   - Perform post-DMA cache flushes on systems with MAARs
   - Probe the I6500 CPU
   - Cleanup cmpxchg and add support for 1 and 2 byte operations
   - Use queued read/write locks (qrwlock)
   - Use queued spinlocks (qspinlock)
   - Add CPU shared FTLB feature detection
   - Handle tlbex-tlbp race condition
   - Allow storing pgd in C0_CONTEXT for MIPSr6
   - Use current_cpu_type() in m4kc_tlbp_war()
   - Support Boston in the generic kernel

  Generic platform:
   - yamon-dt: Pull YAMON DT shim code out of SEAD-3 board
   - yamon-dt: Support > 256MB of RAM
   - yamon-dt: Use serial* rather than uart* aliases
   - Abstract FDT fixup application
   - Set RTC_ALWAYS_BCD to 0
   - Add a MAINTAINERS entry

  core kernel:
   - qspinlock.c: include linux/prefetch.h

  Loongson 3:
   - Add support

  Perf:
   - Add I6500 support

  SEAD-3:
   - Remove GIC timer from DT
   - Set interrupt-parent per-device, not at root node
   - Fix GIC interrupt specifiers

  SMP:
   - Skip IPI setup if we only have a single CPU

  VDSO:
   - Make comment match reality
   - Improvements to time code in VDSO"

* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (86 commits)
  locking/qspinlock: Include linux/prefetch.h
  MIPS: Fix MIPS I ISA /proc/cpuinfo reporting
  MIPS: Fix minimum alignment requirement of IRQ stack
  MIPS: generic: Support MIPS Boston development boards
  MIPS: DTS: img: Don't attempt to build-in all .dtb files
  clk: boston: Add a driver for MIPS Boston board clocks
  dt-bindings: Document img,boston-clock binding
  MIPS: Traced negative syscalls should return -ENOSYS
  MIPS: Correct forced syscall errors
  MIPS: Negate error syscall return in trace
  MIPS: Drop duplicate HAVE_SYSCALL_TRACEPOINTS select
  MIPS16e2: Provide feature overrides for non-MIPS16 systems
  MIPS: MIPS16e2: Report ASE presence in /proc/cpuinfo
  MIPS: MIPS16e2: Subdecode extended LWSP/SWSP instructions
  MIPS: MIPS16e2: Identify ASE presence
  MIPS: VDSO: Fix a mismatch between comment and preprocessor constant
  MIPS: VDSO: Add implementation of gettimeofday() fallback
  MIPS: VDSO: Add implementation of clock_gettime() fallback
  MIPS: VDSO: Fix conversions in do_monotonic()/do_monotonic_coarse()
  MIPS: Use current_cpu_type() in m4kc_tlbp_war()
  ...

6 files changed, 354 insertions, 193 deletions

diff --git a/arch/mips/generic/Kconfig b/arch/mips/generic/Kconfig
index a606b3f9196c..51ffbbaddee2 100644
--- a/arch/mips/generic/Kconfig
+++ b/arch/mips/generic/Kconfig
@@ -9,11 +9,31 @@ config LEGACY_BOARDS
 	  kernel is booted without being provided with an FDT via the UHI
 	  boot protocol.
 
+config YAMON_DT_SHIM
+	bool
+	help
+	  Select this from your board if the board uses the YAMON bootloader
+	  and you wish to include code which helps translate various
+	  YAMON-provided environment variables into a device tree properties.
+
+comment "Legacy (non-UHI/non-FIT) Boards"
+
 config LEGACY_BOARD_SEAD3
 	bool "Support MIPS SEAD-3 boards"
 	select LEGACY_BOARDS
+	select YAMON_DT_SHIM
 	help
 	  Enable this to include support for booting on MIPS SEAD-3 FPGA-based
 	  development boards, which boot using a legacy boot protocol.
 
+comment "FIT/UHI Boards"
+
+config FIT_IMAGE_FDT_BOSTON
+	bool "Include FDT for MIPS Boston boards"
+	help
+	  Enable this to include the FDT for the MIPS Boston development board
+	  from Imagination Technologies in the FIT kernel image. You should
+	  enable this if you wish to boot on a MIPS Boston board, as it is
+	  expected by the bootloader.
+
 endif
diff --git a/arch/mips/generic/Makefile b/arch/mips/generic/Makefile
index acb9b6d62b16..56b3ea565ed9 100644
--- a/arch/mips/generic/Makefile
+++ b/arch/mips/generic/Makefile
@@ -12,5 +12,6 @@ obj-y += init.o
 obj-y += irq.o
 obj-y += proc.o
 
+obj-$(CONFIG_YAMON_DT_SHIM)		+= yamon-dt.o
 obj-$(CONFIG_LEGACY_BOARD_SEAD3)	+= board-sead3.o
 obj-$(CONFIG_KEXEC)			+= kexec.o
diff --git a/arch/mips/generic/board-sead3.c b/arch/mips/generic/board-sead3.c
index f4ae0584a33b..f109a6b9fdd0 100644
--- a/arch/mips/generic/board-sead3.c
+++ b/arch/mips/generic/board-sead3.c
@@ -13,10 +13,12 @@
 #include <linux/errno.h>
 #include <linux/libfdt.h>
 #include <linux/printk.h>
+#include <linux/sizes.h>
 
 #include <asm/fw/fw.h>
 #include <asm/io.h>
 #include <asm/machine.h>
+#include <asm/yamon-dt.h>
 
 #define SEAD_CONFIG			CKSEG1ADDR(0x1b100110)
 #define SEAD_CONFIG_GIC_PRESENT		BIT(1)
@@ -25,6 +27,15 @@
 #define MIPS_REVISION_MACHINE		(0xf << 4)
 #define MIPS_REVISION_MACHINE_SEAD3	(0x4 << 4)
 
+/*
+ * Maximum 384MB RAM at physical address 0, preceding any I/O.
+ */
+static struct yamon_mem_region mem_regions[] __initdata = {
+	/* start	size */
+	{ 0,		SZ_256M + SZ_128M },
+	{}
+};
+
 static __init bool sead3_detect(void)
 {
 	uint32_t rev;
@@ -33,96 +44,9 @@ static __init bool sead3_detect(void)
 	return (rev & MIPS_REVISION_MACHINE) == MIPS_REVISION_MACHINE_SEAD3;
 }
 
-static __init int append_cmdline(void *fdt)
-{
-	int err, chosen_off;
-
-	/* find or add chosen node */
-	chosen_off = fdt_path_offset(fdt, "/chosen");
-	if (chosen_off == -FDT_ERR_NOTFOUND)
-		chosen_off = fdt_path_offset(fdt, "/chosen@0");
-	if (chosen_off == -FDT_ERR_NOTFOUND)
-		chosen_off = fdt_add_subnode(fdt, 0, "chosen");
-	if (chosen_off < 0) {
-		pr_err("Unable to find or add DT chosen node: %d\n",
-		       chosen_off);
-		return chosen_off;
-	}
-
-	err = fdt_setprop_string(fdt, chosen_off, "bootargs", fw_getcmdline());
-	if (err) {
-		pr_err("Unable to set bootargs property: %d\n", err);
-		return err;
-	}
-
-	return 0;
-}
-
 static __init int append_memory(void *fdt)
 {
-	unsigned long phys_memsize, memsize;
-	__be32 mem_array[2];
-	int err, mem_off;
-	char *var;
-
-	/* find memory size from the bootloader environment */
-	var = fw_getenv("memsize");
-	if (var) {
-		err = kstrtoul(var, 0, &phys_memsize);
-		if (err) {
-			pr_err("Failed to read memsize env variable '%s'\n",
-			       var);
-			return -EINVAL;
-		}
-	} else {
-		pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
-		phys_memsize = 32 << 20;
-	}
-
-	/* default to using all available RAM */
-	memsize = phys_memsize;
-
-	/* allow the user to override the usable memory */
-	var = strstr(arcs_cmdline, "memsize=");
-	if (var)
-		memsize = memparse(var + strlen("memsize="), NULL);
-
-	/* if the user says there's more RAM than we thought, believe them */
-	phys_memsize = max_t(unsigned long, phys_memsize, memsize);
-
-	/* find or add a memory node */
-	mem_off = fdt_path_offset(fdt, "/memory");
-	if (mem_off == -FDT_ERR_NOTFOUND)
-		mem_off = fdt_add_subnode(fdt, 0, "memory");
-	if (mem_off < 0) {
-		pr_err("Unable to find or add memory DT node: %d\n", mem_off);
-		return mem_off;
-	}
-
-	err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
-	if (err) {
-		pr_err("Unable to set memory node device_type: %d\n", err);
-		return err;
-	}
-
-	mem_array[0] = 0;
-	mem_array[1] = cpu_to_be32(phys_memsize);
-	err = fdt_setprop(fdt, mem_off, "reg", mem_array, sizeof(mem_array));
-	if (err) {
-		pr_err("Unable to set memory regs property: %d\n", err);
-		return err;
-	}
-
-	mem_array[0] = 0;
-	mem_array[1] = cpu_to_be32(memsize);
-	err = fdt_setprop(fdt, mem_off, "linux,usable-memory",
-			  mem_array, sizeof(mem_array));
-	if (err) {
-		pr_err("Unable to set linux,usable-memory property: %d\n", err);
-		return err;
-	}
-
-	return 0;
+	return yamon_dt_append_memory(fdt, mem_regions);
 }
 
 static __init int remove_gic(void *fdt)
@@ -163,14 +87,16 @@ static __init int remove_gic(void *fdt)
 		return -EINVAL;
 	}
 
-	err = fdt_setprop_u32(fdt, 0, "interrupt-parent", cpu_phandle);
-	if (err) {
-		pr_err("unable to set root interrupt-parent: %d\n", err);
-		return err;
-	}
-
 	uart_off = fdt_node_offset_by_compatible(fdt, -1, "ns16550a");
 	while (uart_off >= 0) {
+		err = fdt_setprop_u32(fdt, uart_off, "interrupt-parent",
+				      cpu_phandle);
+		if (err) {
+			pr_warn("unable to set UART interrupt-parent: %d\n",
+				err);
+			return err;
+		}
+
 		err = fdt_setprop_u32(fdt, uart_off, "interrupts",
 				      cpu_uart_int);
 		if (err) {
@@ -193,6 +119,12 @@ static __init int remove_gic(void *fdt)
 		return eth_off;
 	}
 
+	err = fdt_setprop_u32(fdt, eth_off, "interrupt-parent", cpu_phandle);
+	if (err) {
+		pr_err("unable to set ethernet interrupt-parent: %d\n", err);
+		return err;
+	}
+
 	err = fdt_setprop_u32(fdt, eth_off, "interrupts", cpu_eth_int);
 	if (err) {
 		pr_err("unable to set ethernet interrupts property: %d\n", err);
@@ -205,94 +137,29 @@ static __init int remove_gic(void *fdt)
 		return ehci_off;
 	}
 
-	err = fdt_setprop_u32(fdt, ehci_off, "interrupts", cpu_ehci_int);
+	err = fdt_setprop_u32(fdt, ehci_off, "interrupt-parent", cpu_phandle);
 	if (err) {
-		pr_err("unable to set EHCI interrupts property: %d\n", err);
+		pr_err("unable to set EHCI interrupt-parent: %d\n", err);
 		return err;
 	}
 
-	return 0;
-}
-
-static __init int serial_config(void *fdt)
-{
-	const char *yamontty, *mode_var;
-	char mode_var_name[9], path[18], parity;
-	unsigned int uart, baud, stop_bits;
-	bool hw_flow;
-	int chosen_off, err;
-
-	yamontty = fw_getenv("yamontty");
-	if (!yamontty || !strcmp(yamontty, "tty0")) {
-		uart = 0;
-	} else if (!strcmp(yamontty, "tty1")) {
-		uart = 1;
-	} else {
-		pr_warn("yamontty environment variable '%s' invalid\n",
-			yamontty);
-		uart = 0;
-	}
-
-	baud = stop_bits = 0;
-	parity = 0;
-	hw_flow = false;
-
-	snprintf(mode_var_name, sizeof(mode_var_name), "modetty%u", uart);
-	mode_var = fw_getenv(mode_var_name);
-	if (mode_var) {
-		while (mode_var[0] >= '0' && mode_var[0] <= '9') {
-			baud *= 10;
-			baud += mode_var[0] - '0';
-			mode_var++;
-		}
-		if (mode_var[0] == ',')
-			mode_var++;
-		if (mode_var[0])
-			parity = mode_var[0];
-		if (mode_var[0] == ',')
-			mode_var++;
-		if (mode_var[0])
-			stop_bits = mode_var[0] - '0';
-		if (mode_var[0] == ',')
-			mode_var++;
-		if (!strcmp(mode_var, "hw"))
-			hw_flow = true;
-	}
-
-	if (!baud)
-		baud = 38400;
-
-	if (parity != 'e' && parity != 'n' && parity != 'o')
-		parity = 'n';
-
-	if (stop_bits != 7 && stop_bits != 8)
-		stop_bits = 8;
-
-	WARN_ON(snprintf(path, sizeof(path), "uart%u:%u%c%u%s",
-			 uart, baud, parity, stop_bits,
-			 hw_flow ? "r" : "") >= sizeof(path));
-
-	/* find or add chosen node */
-	chosen_off = fdt_path_offset(fdt, "/chosen");
-	if (chosen_off == -FDT_ERR_NOTFOUND)
-		chosen_off = fdt_path_offset(fdt, "/chosen@0");
-	if (chosen_off == -FDT_ERR_NOTFOUND)
-		chosen_off = fdt_add_subnode(fdt, 0, "chosen");
-	if (chosen_off < 0) {
-		pr_err("Unable to find or add DT chosen node: %d\n",
-		       chosen_off);
-		return chosen_off;
-	}
-
-	err = fdt_setprop_string(fdt, chosen_off, "stdout-path", path);
+	err = fdt_setprop_u32(fdt, ehci_off, "interrupts", cpu_ehci_int);
 	if (err) {
-		pr_err("Unable to set stdout-path property: %d\n", err);
+		pr_err("unable to set EHCI interrupts property: %d\n", err);
 		return err;
 	}
 
 	return 0;
 }
 
+static const struct mips_fdt_fixup sead3_fdt_fixups[] __initconst = {
+	{ yamon_dt_append_cmdline, "append command line" },
+	{ append_memory, "append memory" },
+	{ remove_gic, "remove GIC when not present" },
+	{ yamon_dt_serial_config, "append serial configuration" },
+	{ },
+};
+
 static __init const void *sead3_fixup_fdt(const void *fdt,
 					  const void *match_data)
 {
@@ -307,29 +174,10 @@ static __init const void *sead3_fixup_fdt(const void *fdt,
 
 	fw_init_cmdline();
 
-	err = fdt_open_into(fdt, fdt_buf, sizeof(fdt_buf));
-	if (err)
-		panic("Unable to open FDT: %d", err);
-
-	err = append_cmdline(fdt_buf);
-	if (err)
-		panic("Unable to patch FDT: %d", err);
-
-	err = append_memory(fdt_buf);
-	if (err)
-		panic("Unable to patch FDT: %d", err);
-
-	err = remove_gic(fdt_buf);
-	if (err)
-		panic("Unable to patch FDT: %d", err);
-
-	err = serial_config(fdt_buf);
-	if (err)
-		panic("Unable to patch FDT: %d", err);
-
-	err = fdt_pack(fdt_buf);
+	err = apply_mips_fdt_fixups(fdt_buf, sizeof(fdt_buf),
+				    fdt, sead3_fdt_fixups);
 	if (err)
-		panic("Unable to pack FDT: %d\n", err);
+		panic("Unable to fixup FDT: %d", err);
 
 	return fdt_buf;
 }
diff --git a/arch/mips/generic/init.c b/arch/mips/generic/init.c
index 1231b5a17b37..3f32b376d30e 100644
--- a/arch/mips/generic/init.c
+++ b/arch/mips/generic/init.c
@@ -122,6 +122,33 @@ void __init device_tree_init(void)
 		err = register_up_smp_ops();
 }
 
+int __init apply_mips_fdt_fixups(void *fdt_out, size_t fdt_out_size,
+				 const void *fdt_in,
+				 const struct mips_fdt_fixup *fixups)
+{
+	int err;
+
+	err = fdt_open_into(fdt_in, fdt_out, fdt_out_size);
+	if (err) {
+		pr_err("Failed to open FDT\n");
+		return err;
+	}
+
+	for (; fixups->apply; fixups++) {
+		err = fixups->apply(fdt_out);
+		if (err) {
+			pr_err("Failed to apply FDT fixup \"%s\"\n",
+			       fixups->description);
+			return err;
+		}
+	}
+
+	err = fdt_pack(fdt_out);
+	if (err)
+		pr_err("Failed to pack FDT\n");
+	return err;
+}
+
 void __init plat_time_init(void)
 {
 	struct device_node *np;
diff --git a/arch/mips/generic/vmlinux.its.S b/arch/mips/generic/vmlinux.its.S
index f67fbf1c8541..3390e2f80b80 100644
--- a/arch/mips/generic/vmlinux.its.S
+++ b/arch/mips/generic/vmlinux.its.S
@@ -29,3 +29,28 @@
 		};
 	};
 };
+
+#ifdef CONFIG_FIT_IMAGE_FDT_BOSTON
+/ {
+	images {
+		fdt@boston {
+			description = "img,boston Device Tree";
+			data = /incbin/("boot/dts/img/boston.dtb");
+			type = "flat_dt";
+			arch = "mips";
+			compression = "none";
+			hash@0 {
+				algo = "sha1";
+			};
+		};
+	};
+
+	configurations {
+		conf@boston {
+			description = "Boston Linux kernel";
+			kernel = "kernel@0";
+			fdt = "fdt@boston";
+		};
+	};
+};
+#endif /* CONFIG_FIT_IMAGE_FDT_BOSTON */
diff --git a/arch/mips/generic/yamon-dt.c b/arch/mips/generic/yamon-dt.c
new file mode 100644
index 000000000000..6077bca9b364
--- /dev/null
+++ b/arch/mips/generic/yamon-dt.c
@@ -0,0 +1,240 @@
+/*
+ * Copyright (C) 2016 Imagination Technologies
+ * Author: Paul Burton <paul.burton@imgtec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#define pr_fmt(fmt) "yamon-dt: " fmt
+
+#include <linux/bug.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/libfdt.h>
+#include <linux/printk.h>
+
+#include <asm/fw/fw.h>
+#include <asm/yamon-dt.h>
+
+#define MAX_MEM_ARRAY_ENTRIES	2
+
+__init int yamon_dt_append_cmdline(void *fdt)
+{
+	int err, chosen_off;
+
+	/* find or add chosen node */
+	chosen_off = fdt_path_offset(fdt, "/chosen");
+	if (chosen_off == -FDT_ERR_NOTFOUND)
+		chosen_off = fdt_path_offset(fdt, "/chosen@0");
+	if (chosen_off == -FDT_ERR_NOTFOUND)
+		chosen_off = fdt_add_subnode(fdt, 0, "chosen");
+	if (chosen_off < 0) {
+		pr_err("Unable to find or add DT chosen node: %d\n",
+		       chosen_off);
+		return chosen_off;
+	}
+
+	err = fdt_setprop_string(fdt, chosen_off, "bootargs", fw_getcmdline());
+	if (err) {
+		pr_err("Unable to set bootargs property: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static unsigned int __init gen_fdt_mem_array(
+					const struct yamon_mem_region *regions,
+					__be32 *mem_array,
+					unsigned int max_entries,
+					unsigned long memsize)
+{
+	const struct yamon_mem_region *mr;
+	unsigned long size;
+	unsigned int entries = 0;
+
+	for (mr = regions; mr->size && memsize; ++mr) {
+		if (entries >= max_entries) {
+			pr_warn("Number of regions exceeds max %u\n",
+				max_entries);
+			break;
+		}
+
+		/* How much of the remaining RAM fits in the next region? */
+		size = min_t(unsigned long, memsize, mr->size);
+		memsize -= size;
+
+		/* Emit a memory region */
+		*(mem_array++) = cpu_to_be32(mr->start);
+		*(mem_array++) = cpu_to_be32(size);
+		++entries;
+
+		/* Discard the next mr->discard bytes */
+		memsize -= min_t(unsigned long, memsize, mr->discard);
+	}
+	return entries;
+}
+
+__init int yamon_dt_append_memory(void *fdt,
+				  const struct yamon_mem_region *regions)
+{
+	unsigned long phys_memsize, memsize;
+	__be32 mem_array[2 * MAX_MEM_ARRAY_ENTRIES];
+	unsigned int mem_entries;
+	int i, err, mem_off;
+	char *var, param_name[10], *var_names[] = {
+		"ememsize", "memsize",
+	};
+
+	/* find memory size from the bootloader environment */
+	for (i = 0; i < ARRAY_SIZE(var_names); i++) {
+		var = fw_getenv(var_names[i]);
+		if (!var)
+			continue;
+
+		err = kstrtoul(var, 0, &phys_memsize);
+		if (!err)
+			break;
+
+		pr_warn("Failed to read the '%s' env variable '%s'\n",
+			var_names[i], var);
+	}
+
+	if (!phys_memsize) {
+		pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
+		phys_memsize = 32 << 20;
+	}
+
+	/* default to using all available RAM */
+	memsize = phys_memsize;
+
+	/* allow the user to override the usable memory */
+	for (i = 0; i < ARRAY_SIZE(var_names); i++) {
+		snprintf(param_name, sizeof(param_name), "%s=", var_names[i]);
+		var = strstr(arcs_cmdline, param_name);
+		if (!var)
+			continue;
+
+		memsize = memparse(var + strlen(param_name), NULL);
+	}
+
+	/* if the user says there's more RAM than we thought, believe them */
+	phys_memsize = max_t(unsigned long, phys_memsize, memsize);
+
+	/* find or add a memory node */
+	mem_off = fdt_path_offset(fdt, "/memory");
+	if (mem_off == -FDT_ERR_NOTFOUND)
+		mem_off = fdt_add_subnode(fdt, 0, "memory");
+	if (mem_off < 0) {
+		pr_err("Unable to find or add memory DT node: %d\n", mem_off);
+		return mem_off;
+	}
+
+	err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
+	if (err) {
+		pr_err("Unable to set memory node device_type: %d\n", err);
+		return err;
+	}
+
+	mem_entries = gen_fdt_mem_array(regions, mem_array,
+					MAX_MEM_ARRAY_ENTRIES, phys_memsize);
+	err = fdt_setprop(fdt, mem_off, "reg",
+			  mem_array, mem_entries * 2 * sizeof(mem_array[0]));
+	if (err) {
+		pr_err("Unable to set memory regs property: %d\n", err);
+		return err;
+	}
+
+	mem_entries = gen_fdt_mem_array(regions, mem_array,
+					MAX_MEM_ARRAY_ENTRIES, memsize);
+	err = fdt_setprop(fdt, mem_off, "linux,usable-memory",
+			  mem_array, mem_entries * 2 * sizeof(mem_array[0]));
+	if (err) {
+		pr_err("Unable to set linux,usable-memory property: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+__init int yamon_dt_serial_config(void *fdt)
+{
+	const char *yamontty, *mode_var;
+	char mode_var_name[9], path[20], parity;
+	unsigned int uart, baud, stop_bits;
+	bool hw_flow;
+	int chosen_off, err;
+
+	yamontty = fw_getenv("yamontty");
+	if (!yamontty || !strcmp(yamontty, "tty0")) {
+		uart = 0;
+	} else if (!strcmp(yamontty, "tty1")) {
+		uart = 1;
+	} else {
+		pr_warn("yamontty environment variable '%s' invalid\n",
+			yamontty);
+		uart = 0;
+	}
+
+	baud = stop_bits = 0;
+	parity = 0;
+	hw_flow = false;
+
+	snprintf(mode_var_name, sizeof(mode_var_name), "modetty%u", uart);
+	mode_var = fw_getenv(mode_var_name);
+	if (mode_var) {
+		while (mode_var[0] >= '0' && mode_var[0] <= '9') {
+			baud *= 10;
+			baud += mode_var[0] - '0';
+			mode_var++;
+		}
+		if (mode_var[0] == ',')
+			mode_var++;
+		if (mode_var[0])
+			parity = mode_var[0];
+		if (mode_var[0] == ',')
+			mode_var++;
+		if (mode_var[0])
+			stop_bits = mode_var[0] - '0';
+		if (mode_var[0] == ',')
+			mode_var++;
+		if (!strcmp(mode_var, "hw"))
+			hw_flow = true;
+	}
+
+	if (!baud)
+		baud = 38400;
+
+	if (parity != 'e' && parity != 'n' && parity != 'o')
+		parity = 'n';
+
+	if (stop_bits != 7 && stop_bits != 8)
+		stop_bits = 8;
+
+	WARN_ON(snprintf(path, sizeof(path), "serial%u:%u%c%u%s",
+			 uart, baud, parity, stop_bits,
+			 hw_flow ? "r" : "") >= sizeof(path));
+
+	/* find or add chosen node */
+	chosen_off = fdt_path_offset(fdt, "/chosen");
+	if (chosen_off == -FDT_ERR_NOTFOUND)
+		chosen_off = fdt_path_offset(fdt, "/chosen@0");
+	if (chosen_off == -FDT_ERR_NOTFOUND)
+		chosen_off = fdt_add_subnode(fdt, 0, "chosen");
+	if (chosen_off < 0) {
+		pr_err("Unable to find or add DT chosen node: %d\n",
+		       chosen_off);
+		return chosen_off;
+	}
+
+	err = fdt_setprop_string(fdt, chosen_off, "stdout-path", path);
+	if (err) {
+		pr_err("Unable to set stdout-path property: %d\n", err);
+		return err;
+	}
+
+	return 0;
+}