[PATCH] Add uboot commandline argument passing support to m68knommu
From: Lennart Sorensen
Date: Fri Sep 18 2009 - 12:27:42 EST
This patch adds m68knommu support for getting the kernel command line
arguments from uboot, including the passing of an initrd image from uboot.
We use this on a 5270/5271 based board, and have used it on the 5271evb
development board. It is based on a patch found in the linux-2.6-denx
git tree, although that tree seems to have had lots of other changes
since which are not in the main Linus kernel. I believe this will work
on all coldfires, although other m68knommu might be missing the _init_sp
stuff in head.S as far as I can tell. I only have the coldfire to
test on.
Signed-off-by: Lennart Sorensen <lsorense@xxxxxxxxxxxxxxxxxxx>
diff --git a/arch/m68knommu/Kconfig b/arch/m68knommu/Kconfig
index e2201b9..064f591 100644
--- a/arch/m68knommu/Kconfig
+++ b/arch/m68knommu/Kconfig
@@ -533,6 +533,13 @@ config AVNET
default y
depends on (AVNET5282)
+config UBOOT
+ bool "Support for U-Boot command line parameters"
+ help
+ If you say Y here kernel will try to collect command
+ line parameters from the initial u-boot stack.
+ default n
+
config 4KSTACKS
bool "Use 4Kb for kernel stacks instead of 8Kb"
default y
diff --git a/arch/m68knommu/kernel/setup.c b/arch/m68knommu/kernel/setup.c
index 5c2bb3e..0e2114e 100644
--- a/arch/m68knommu/kernel/setup.c
+++ b/arch/m68knommu/kernel/setup.c
@@ -29,6 +29,8 @@
#include <linux/bootmem.h>
#include <linux/seq_file.h>
#include <linux/init.h>
+#include <linux/initrd.h>
+#include <linux/root_dev.h>
#include <asm/setup.h>
#include <asm/irq.h>
@@ -52,6 +54,9 @@ void (*mach_reset)(void);
void (*mach_halt)(void);
void (*mach_power_off)(void);
+#if defined(CONFIG_UBOOT)
+void parse_uboot_commandline(char *commandp, int size);
+#endif
#ifdef CONFIG_M68000
#define CPU "MC68000"
@@ -128,7 +133,23 @@ void __init setup_arch(char **cmdline_p)
#if defined(CONFIG_BOOTPARAM)
strncpy(&command_line[0], CONFIG_BOOTPARAM_STRING, sizeof(command_line));
command_line[sizeof(command_line) - 1] = 0;
-#endif
+#endif /* CONFIG_BOOTPARAM */
+
+#if defined(CONFIG_UBOOT)
+ /* CONFIG_UBOOT and CONFIG_BOOTPARAM defined, concatenate cmdline */
+ #if defined(CONFIG_BOOTPARAM)
+ /* Add the whitespace separator */
+ command_line[strlen(CONFIG_BOOTPARAM_STRING)] = ' ';
+ /* Parse uboot command line into the rest of the buffer */
+ parse_uboot_commandline(
+ &command_line[(strlen(CONFIG_BOOTPARAM_STRING)+1)],
+ (sizeof(command_line) - (strlen(CONFIG_BOOTPARAM_STRING)+1)));
+ /* Only CONFIG_UBOOT defined, create cmdline */
+ #else
+ parse_uboot_commandline(&command_line[0], sizeof(command_line));
+ #endif /* CONFIG_BOOTPARAM */
+ command_line[sizeof(command_line) - 1] = 0;
+#endif /* CONFIG_UBOOT */
printk(KERN_INFO "\x0F\r\n\nuClinux/" CPU "\n");
@@ -204,12 +225,82 @@ void __init setup_arch(char **cmdline_p)
free_bootmem(memory_start, memory_end - memory_start);
reserve_bootmem(memory_start, bootmap_size, BOOTMEM_DEFAULT);
+#if defined(CONFIG_UBOOT) && defined(CONFIG_BLK_DEV_INITRD)
+ if((initrd_start > 0) && (initrd_start < initrd_end) && (initrd_end < memory_end)) {
+ reserve_bootmem(initrd_start, initrd_end - initrd_start, BOOTMEM_DEFAULT);
+ }
+#endif /* if defined(CONFIG_BLK_DEV_INITRD) */
+
/*
* Get kmalloc into gear.
*/
paging_init();
}
+#if defined(CONFIG_UBOOT)
+/*
+ * parse_uboot_commandline
+ *
+ * Copies u-boot commandline arguments and store them in the proper linux
+ * variables.
+ *
+ * Assumes:
+ * _init_sp global contains the address in the stack pointer when the
+ * kernel starts (see head.S::_start)
+ *
+ * U-Boot calling convention:
+ * (*kernel) (kbd, initrd_start, initrd_end, cmd_start, cmd_end);
+ *
+ * _init_sp can be parsed as such
+ *
+ * _init_sp+00 = u-boot cmd after jsr into kernel (skip)
+ * _init_sp+04 = &kernel board_info (residual data)
+ * _init_sp+08 = &initrd_start
+ * _init_sp+12 = &initrd_end
+ * _init_sp+16 = &cmd_start
+ * _init_sp+20 = &cmd_end
+ *
+ * This also assumes that the memory locations pointed to are still
+ * unmodified. U-boot places them near the end of external SDRAM.
+ *
+ * Argument(s):
+ * commandp = the linux commandline arg container to fill.
+ * size = the sizeof commandp.
+ *
+ * Returns:
+ */
+void parse_uboot_commandline(char *commandp, int size)
+{
+ extern unsigned long _init_sp;
+ unsigned long *sp;
+ unsigned long uboot_kbd;
+ unsigned long uboot_initrd_start, uboot_initrd_end;
+ unsigned long uboot_cmd_start, uboot_cmd_end;
+
+
+ sp = (unsigned long *)_init_sp;
+ uboot_kbd = sp[1];
+ uboot_initrd_start = sp[2];
+ uboot_initrd_end = sp[3];
+ uboot_cmd_start = sp[4];
+ uboot_cmd_end = sp[5];
+
+ if (uboot_cmd_start && uboot_cmd_end) {
+ strncpy(commandp, (const char *)uboot_cmd_start, size);
+ }
+#if defined(CONFIG_BLK_DEV_INITRD)
+ if (uboot_initrd_start && uboot_initrd_end &&
+ (uboot_initrd_end > uboot_initrd_start)) {
+ initrd_start = uboot_initrd_start;
+ initrd_end = uboot_initrd_end;
+ ROOT_DEV = Root_RAM0;
+ printk("initrd at 0x%lx:0x%lx\n",
+ initrd_start, initrd_end);
+ }
+#endif /* if defined(CONFIG_BLK_DEV_INITRD) */
+}
+#endif /* #if defined(CONFIG_UBOOT) */
+
/*
* Get CPU information for use by the procfs.
*/
diff --git a/arch/m68knommu/platform/coldfire/head.S b/arch/m68knommu/platform/coldfire/head.S
index 2b0d73c..4b91aa2 100644
--- a/arch/m68knommu/platform/coldfire/head.S
+++ b/arch/m68knommu/platform/coldfire/head.S
@@ -106,6 +106,9 @@
.global _ramvec
.global _ramstart
.global _ramend
+#if defined(CONFIG_UBOOT)
+.global _init_sp
+#endif
/*****************************************************************************/
@@ -124,6 +127,10 @@ _ramstart:
.long 0
_ramend:
.long 0
+#if defined(CONFIG_UBOOT)
+_init_sp:
+.long 0
+#endif
/*****************************************************************************/
@@ -137,6 +144,9 @@ __HEAD
_start:
nop /* filler */
movew #0x2700, %sr /* no interrupts */
+#if defined(CONFIG_UBOOT)
+ movel %sp,_init_sp /* save initial stack pointer */
+#endif
/*
* Do any platform or board specific setup now. Most boards
--
Len Sorensen
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