[Xen-devel] [PATCH 4/8] arm: link a device tree blob into the xen image

[David Vrabel <david.vrabel@xxxxxxxxxx>]

From: David Vrabel <david.vrabel@xxxxxxxxxx>

Link a device tree blob (DTB) into the xen image.  This is loaded
immediately after Xen and xen_start() is called with the correct
address in atag_paddr.

The DTB file must be supplied by setting the CONFIG_DTB_FILE variable
in .config or on the make command line.

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
---
 config/arm.mk          |    6 ++++++
 xen/arch/arm/Makefile  |    9 ++++++++-
 xen/arch/arm/dtb.S     |    2 ++
 xen/arch/arm/head.S    |    6 ++++++
 xen/arch/arm/xen.lds.S |    4 ++++
 5 files changed, 26 insertions(+), 1 deletions(-)
 create mode 100644 xen/arch/arm/dtb.S

diff --git a/config/arm.mk b/config/arm.mk
index f64f0c1..f20fd2d 100644
--- a/config/arm.mk
+++ b/config/arm.mk
@@ -16,3 +16,9 @@ LDFLAGS_DIRECT_Linux = _linux
 LDFLAGS_DIRECT += -marmelf$(LDFLAGS_DIRECT_$(XEN_OS))_eabi
 
 CONFIG_LOAD_ADDRESS ?= 0x80000000
+
+# XXX: When running on the model there is no bootloader to provide a
+# device tree.  It must be linked into Xen.
+ifndef CONFIG_DTB_FILE
+$(error CONFIG_DTB_FILE must be set to the absolute filename of a DTB)
+endif
diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 9bc2fc8..b4dd3b1 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -22,12 +22,17 @@ obj-y += vtimer.o
 
 #obj-bin-y += ....o
 
+ifdef CONFIG_DTB_FILE
+obj-y += dtb.o
+AFLAGS += -DCONFIG_DTB_FILE=\"$(CONFIG_DTB_FILE)\"
+endif
+
 ALL_OBJS := head.o $(ALL_OBJS)
 
 $(TARGET): $(TARGET)-syms
        # XXX: VE model loads by VMA so instead of
        # making a proper ELF we link with LMA == VMA and adjust crudely
-       $(OBJCOPY) --change-addresses +0x7fe00000 $< $@
+       $(OBJCOPY) --change-addresses +0x80000000 $< $@
        # XXX strip it
 
 #$(TARGET): $(TARGET)-syms $(efi-y) boot/mkelf32
@@ -71,6 +76,8 @@ xen.lds: xen.lds.S
        sed -e 's/xen\.lds\.o:/xen\.lds:/g' <.xen.lds.d >.xen.lds.d.new
        mv -f .xen.lds.d.new .xen.lds.d
 
+dtb.o: $(CONFIG_DTB_FILE)
+
 .PHONY: clean
 clean::
        rm -f asm-offsets.s xen.lds
diff --git a/xen/arch/arm/dtb.S b/xen/arch/arm/dtb.S
new file mode 100644
index 0000000..c703aef
--- /dev/null
+++ b/xen/arch/arm/dtb.S
@@ -0,0 +1,2 @@
+        .section .dtb,#alloc
+        .incbin CONFIG_DTB_FILE
diff --git a/xen/arch/arm/head.S b/xen/arch/arm/head.S
index 57b990d..ea557c2 100644
--- a/xen/arch/arm/head.S
+++ b/xen/arch/arm/head.S
@@ -55,6 +55,12 @@ start:
        adr   r9, start              /* r9  := paddr (start) */
        sub   r10, r9, r0            /* r10 := phys-offset */
 
+        /* Using the DTB in the .dtb section? */
+#ifdef CONFIG_DTB_FILE
+        ldr   r8, =_sdtb
+        add   r8, r10                /* r8 := paddr(DTB) */
+#endif
+
 #ifdef EARLY_UART_ADDRESS
        /* Say hello */
        ldr   r11, =EARLY_UART_ADDRESS  /* r11 := UART base address */
diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 5a62e2c..6fb7662 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -122,6 +122,10 @@ SECTIONS
   } :text
   _end = . ;
 
+  /* Section for the device tree blob (if any). */
+  _sdtb = .;
+  .dtb : { *(.dtb) } :text
+
   /* Sections to be discarded */
   /DISCARD/ : {
        *(.exit.text)
-- 
1.7.2.5


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