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-rw-r--r--Documentation/boards/bcm2835.rst6
-rw-r--r--arch/arm/boards/raspberry-pi/rpi-common.c47
2 files changed, 53 insertions, 0 deletions
diff --git a/Documentation/boards/bcm2835.rst b/Documentation/boards/bcm2835.rst
index 95e9108..e9ad1d4 100644
--- a/Documentation/boards/bcm2835.rst
+++ b/Documentation/boards/bcm2835.rst
@@ -34,5 +34,11 @@ VideoCore firmware creates a device tree based on the entries in ``config.txt``.
bootm -o /vc.dtb /boot/kernel7.img
+VideoCore device tree also contains the kernel command-line that is constructed from ``cmdline.txt`` and other parameters internally determined by the VideoCore firmware. Normally in Barebox this command-line gets overwritten on boot by the Linux bootargs (see :ref:`booting_linux`).
+
+The original command-line from VideoCore device tree is available to the Barebox environment in the ``vc.bootargs`` global variable. For example, to append it to the Linux bootargs::
+
+ global linux.bootargs.vc="$global.vc.bootargs"
+
.. _Raspberry Pi firmware: https://codeload.github.com/raspberrypi/firmware/zip/80e1fbeb78f9df06701d28c0ed3a3060a3f557ef
.. _documentation for config.txt: https://www.raspberrypi.org/documentation/configuration/config-txt/
diff --git a/arch/arm/boards/raspberry-pi/rpi-common.c b/arch/arm/boards/raspberry-pi/rpi-common.c
index fffa882..9d334cd 100644
--- a/arch/arm/boards/raspberry-pi/rpi-common.c
+++ b/arch/arm/boards/raspberry-pi/rpi-common.c
@@ -30,6 +30,7 @@
#include <asm/barebox-arm.h>
#include <generated/mach-types.h>
#include <linux/sizes.h>
+#include <globalvar.h>
#include <mach/core.h>
#include <mach/mbox.h>
@@ -375,11 +376,50 @@ static int rpi_env_init(void)
return 0;
}
+/* Extract /chosen/bootargs from the VideoCore FDT into vc.bootargs
+ * global variable. */
+static int rpi_vc_fdt_bootargs(void *fdt)
+{
+ int ret = 0;
+ struct device_node *root = NULL, *node;
+ const char *cmdline;
+
+ root = of_unflatten_dtb(fdt);
+ if (IS_ERR(root)) {
+ ret = PTR_ERR(root);
+ root = NULL;
+ goto out;
+ }
+
+ node = of_find_node_by_path_from(root, "/chosen");
+ if (!node) {
+ pr_err("no /chosen node\n");
+ ret = -ENOENT;
+ goto out;
+ }
+
+ cmdline = of_get_property(node, "bootargs", NULL);
+ if (!cmdline) {
+ pr_err("no bootargs property in the /chosen node\n");
+ ret = -ENOENT;
+ goto out;
+ }
+
+ globalvar_add_simple("vc.bootargs", cmdline);
+
+out:
+ if (root)
+ of_delete_node(root);
+
+ return ret;
+}
+
static void rpi_vc_fdt(void)
{
void *saved_vc_fdt;
struct fdt_header *oftree;
unsigned long magic, size;
+ int ret;
/* VideoCore FDT was copied in PBL just above Barebox memory */
saved_vc_fdt = (void *)(arm_mem_endmem_get());
@@ -401,6 +441,13 @@ static void rpi_vc_fdt(void)
pr_err("failed to save videocore fdt to a file\n");
return;
}
+
+ ret = rpi_vc_fdt_bootargs(saved_vc_fdt);
+ if (ret) {
+ pr_err("failed to extract bootargs from videocore fdt: %d\n",
+ ret);
+ return;
+ }
}
static int rpi_devices_init(void)