6 files changed, 183 insertions, 0 deletions

diff --git a/Documentation/devicetree/booting-without-of.txt b/Documentation/devicetree/booting-without-of.txt
index 04d34f6a58f3..3f1437fbca6b 100644
--- a/Documentation/devicetree/booting-without-of.txt
+++ b/Documentation/devicetree/booting-without-of.txt
@@ -16,6 +16,7 @@ Table of Contents
     2) Entry point for arch/powerpc
     3) Entry point for arch/x86
     4) Entry point for arch/mips/bmips
+    5) Entry point for arch/sh
 
   II - The DT block format
     1) Header
@@ -316,6 +317,18 @@ it with special cases.
   This convention is defined for 32-bit systems only, as there are not
   currently any 64-bit BMIPS implementations.
 
+5) Entry point for arch/sh
+--------------------------
+
+  Device-tree-compatible SH bootloaders are expected to provide the physical
+  address of the device tree blob in r4. Since legacy bootloaders did not
+  guarantee any particular initial register state, kernels built to
+  inter-operate with old bootloaders must either use a builtin DTB or
+  select a legacy board option (something other than CONFIG_SH_DEVICE_TREE)
+  that does not use device tree. Support for the latter is being phased out
+  in favor of device tree.
+
+
 II - The DT block format
 ========================
 
diff --git a/arch/sh/boards/Kconfig b/arch/sh/boards/Kconfig
index 89963d13f930..5e52d5362292 100644
--- a/arch/sh/boards/Kconfig
+++ b/arch/sh/boards/Kconfig
@@ -6,6 +6,21 @@ config SOLUTION_ENGINE
 config SH_ALPHA_BOARD
         bool
 
+config SH_DEVICE_TREE
+        bool "Board Described by Device Tree"
+        select OF
+        select OF_EARLY_FLATTREE
+        select CLKSRC_OF
+        select GENERIC_CALIBRATE_DELAY
+        help
+          Select Board Described by Device Tree to build a kernel that
+          does not hard-code any board-specific knowledge but instead uses
+          a device tree blob provided by the boot-loader. You must enable
+          drivers for any hardware you want to use separately. At this
+          time, only boards based on the open-hardware J-Core processors
+          have sufficient driver coverage to use this option; do not
+          select it if you are using original SuperH hardware.
+
 config SH_SOLUTION_ENGINE
         bool "SolutionEngine"
         select SOLUTION_ENGINE
diff --git a/arch/sh/boards/Makefile b/arch/sh/boards/Makefile
index 975a0f64ff20..cea300362035 100644
--- a/arch/sh/boards/Makefile
+++ b/arch/sh/boards/Makefile
@@ -15,3 +15,5 @@ obj-$(CONFIG_SH_TITAN)		+= board-titan.o
 obj-$(CONFIG_SH_SH7757LCR)      += board-sh7757lcr.o
 obj-$(CONFIG_SH_APSH4A3A)       += board-apsh4a3a.o
 obj-$(CONFIG_SH_APSH4AD0A)      += board-apsh4ad0a.o
+
+obj-$(CONFIG_SH_DEVICE_TREE)    += of-generic.o
diff --git a/arch/sh/boards/of-generic.c b/arch/sh/boards/of-generic.c
new file mode 100644
index 000000000000..71d890932151
--- /dev/null
+++ b/arch/sh/boards/of-generic.c
@@ -0,0 +1,113 @@
+/*
+ * SH generic board support, using device tree
+ *
+ * Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/of_fdt.h>
+#include <linux/of_iommu.h>
+#include <linux/clocksource.h>
+#include <linux/irqchip.h>
+#include <linux/clk-provider.h>
+#include <asm/machvec.h>
+#include <asm/rtc.h>
+
+static void noop(void)
+{
+}
+
+static int noopi(void)
+{
+        return 0;
+}
+
+static void __init sh_of_mem_reserve(void)
+{
+        early_init_fdt_reserve_self();
+        early_init_fdt_scan_reserved_mem();
+}
+
+static void __init sh_of_time_init(void)
+{
+        pr_info("SH generic board support: scanning for clocksource devices\n");
+        clocksource_probe();
+}
+
+static void __init sh_of_setup(char **cmdline_p)
+{
+        unflatten_device_tree();
+
+        board_time_init = sh_of_time_init;
+
+        sh_mv.mv_name = of_flat_dt_get_machine_name();
+        if (!sh_mv.mv_name)
+                sh_mv.mv_name = "Unknown SH model";
+
+        /* FIXME: register smp ops to use dt to find cpus, use
+         * cpu enable-method, and use irq controller's ipi
+         * functions. */
+}
+
+static int sh_of_irq_demux(int irq)
+{
+        /* FIXME: eventually this should not be used at all;
+         * the interrupt controller should set_handle_irq(). */
+        return irq;
+}
+
+static void __init sh_of_init_irq(void)
+{
+        pr_info("SH generic board support: scanning for interrupt controllers\n");
+        irqchip_init();
+}
+
+static int __init sh_of_clk_init(void)
+{
+#ifdef CONFIG_COMMON_CLK
+        /* Disabled pending move to COMMON_CLK framework. */
+        pr_info("SH generic board support: scanning for clk providers\n");
+        of_clk_init(NULL);
+#endif
+        return 0;
+}
+
+static struct sh_machine_vector __initmv sh_of_generic_mv = {
+        .mv_setup       = sh_of_setup,
+        .mv_name        = "devicetree", /* replaced by DT root's model */
+        .mv_irq_demux   = sh_of_irq_demux,
+        .mv_init_irq    = sh_of_init_irq,
+        .mv_clk_init    = sh_of_clk_init,
+        .mv_mode_pins   = noopi,
+        .mv_mem_init    = noop,
+        .mv_mem_reserve = sh_of_mem_reserve,
+};
+
+struct sh_clk_ops;
+
+void __init arch_init_clk_ops(struct sh_clk_ops **ops, int idx)
+{
+}
+
+void __init plat_irq_setup(void)
+{
+}
+
+static int __init sh_of_device_init(void)
+{
+        pr_info("SH generic board support: populating platform devices\n");
+        if (of_have_populated_dt()) {
+                of_iommu_init();
+                of_platform_populate(NULL, of_default_bus_match_table,
+                                     NULL, NULL);
+        } else {
+                pr_crit("Device tree not populated\n");
+        }
+        return 0;
+}
+arch_initcall_sync(sh_of_device_init);
diff --git a/arch/sh/kernel/head_32.S b/arch/sh/kernel/head_32.S
index 7db248936b60..974bc152cc84 100644
--- a/arch/sh/kernel/head_32.S
+++ b/arch/sh/kernel/head_32.S
@@ -66,6 +66,10 @@ ENTRY(_stext)
         mov     #0, r0
         ldc     r0, r6_bank
 #endif
+
+#ifdef CONFIG_OF
+        mov     r4, r12         ! Store device tree blob pointer in r12
+#endif
         
         /*
          * Prefetch if possible to reduce cache miss penalty.
@@ -314,6 +318,12 @@ ENTRY(_stext)
 10:             
 #endif
 
+#ifdef CONFIG_OF
+        mov.l   8f, r0          ! Make flat device tree available early.
+        jsr     @r0
+         mov    r12, r4
+#endif
+
         !                       Additional CPU initialization
         mov.l   6f, r0
         jsr     @r0
@@ -339,6 +349,9 @@ ENTRY(stack_start)
 5:      .long   start_kernel
 6:      .long   cpu_init
 7:      .long   init_thread_union
+#if defined(CONFIG_OF)
+8:      .long   sh_fdt_init
+#endif
 
 #ifdef CONFIG_PMB
 .LPMB_ADDR:             .long   PMB_ADDR
diff --git a/arch/sh/kernel/setup.c b/arch/sh/kernel/setup.c
index de19cfa768f2..efb60ce720a7 100644
--- a/arch/sh/kernel/setup.c
+++ b/arch/sh/kernel/setup.c
@@ -29,6 +29,8 @@
 #include <linux/delay.h>
 #include <linux/platform_device.h>
 #include <linux/memblock.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
 #include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/page.h>
@@ -172,6 +174,7 @@ disable:
 #endif
 }
 
+#ifndef CONFIG_GENERIC_CALIBRATE_DELAY
 void calibrate_delay(void)
 {
         struct clk *clk = clk_get(NULL, "cpu_clk");
@@ -187,6 +190,7 @@ void calibrate_delay(void)
                          (loops_per_jiffy/(5000/HZ)) % 100,
                          loops_per_jiffy);
 }
+#endif
 
 void __init __add_active_range(unsigned int nid, unsigned long start_pfn,
                                                 unsigned long end_pfn)
@@ -238,6 +242,29 @@ void __init __weak plat_early_device_setup(void)
 {
 }
 
+#ifdef CONFIG_OF
+void __ref sh_fdt_init(phys_addr_t dt_phys)
+{
+        static int done = 0;
+        void *dt_virt;
+
+        /* Avoid calling an __init function on secondary cpus. */
+        if (done) return;
+
+        dt_virt = phys_to_virt(dt_phys);
+
+        if (!dt_virt || !early_init_dt_scan(dt_virt)) {
+                pr_crit("Error: invalid device tree blob"
+                        " at physical address %p\n", (void *)dt_phys);
+
+                while (true)
+                        cpu_relax();
+        }
+
+        done = 1;
+}
+#endif
+
 void __init setup_arch(char **cmdline_p)
 {
         enable_mmu();