generic: improve MIPS kexec support

It is based on patches from the linux-longsoon-community git tree:
http://dev.lemote.com/cgit/linux-loongson-community.git/

Now the kernel can use the command line parameter from kexec-tools.

Runtime tested on ar71xx with 2.6.39.4 (the wathdog must be stopped
before executing the new kernel). Compile tested with lantiq (3.1.4)
and brcm47xx (3.0.12).

SVN-Revision: 29674

1 files changed, 88 insertions, 0 deletions

diff --git a/target/linux/generic/patches-3.1/333-mips-kexec-get-kernel-parameters-from-kexec-tools.patch b/target/linux/generic/patches-3.1/333-mips-kexec-get-kernel-parameters-from-kexec-tools.patch
new file mode 100644
index 0000000000..9da936314c
--- /dev/null
+++ b/target/linux/generic/patches-3.1/333-mips-kexec-get-kernel-parameters-from-kexec-tools.patch
@@ -0,0 +1,88 @@
+From 240c76841b26f1b09aaced33414ee1d08b6454cf Mon Sep 17 00:00:00 2001
+From: Wu Zhangjin <wuzhangjin@gmail.com>
+Date: Sat, 15 Jan 2011 12:46:03 +0000
+Subject: MIPS: Get kernel parameters from kexec-tools
+
+Before, we simply use the command lines from the original bootloader,
+but it is not convenient. Now, we accept the kernel parameters from the
+--command-line or --append option of the kexec-tools.  But If not
+--command-line or --apend option indicated, will fall back to use the
+ones from the original bootloader.
+
+Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
+---
+--- a/arch/mips/kernel/machine_kexec.c
++++ b/arch/mips/kernel/machine_kexec.c
+@@ -13,6 +13,7 @@
+ #include <asm/bootinfo.h>
+ #include <asm/cacheflush.h>
+ #include <asm/page.h>
++#include <asm/uaccess.h>
+ 
+ int (*_machine_kexec_prepare)(struct kimage *) = NULL;
+ void (*_machine_kexec_shutdown)(void) = NULL;
+@@ -35,6 +36,56 @@ static void machine_kexec_init_args(void
+ 	pr_info("kexec_args[3] (desc): %p\n", (void *)kexec_args[3]);
+ }
+ 
++#define ARGV_MAX_ARGS (COMMAND_LINE_SIZE / 15)
++
++int machine_kexec_pass_args(struct kimage *image)
++{
++	int i, argc = 0;
++	char *bootloader = "kexec";
++	int *kexec_argv = (int *)kexec_args[1];
++
++	for (i = 0; i < image->nr_segments; i++) {
++		if (!strncmp(bootloader, (char *)image->segment[i].buf,
++				strlen(bootloader))) {
++			/*
++			 * convert command line string to array
++			 * of parameters (as bootloader does).
++			 */
++			/*
++			 * Note: we do treat the 1st string "kexec" as an
++			 * argument ;-) so, argc here is 1.
++			 */
++			char *str = (char *)image->segment[i].buf;
++			char *ptr = strchr(str, ' ');
++			char *kbuf = (char *)kexec_argv[0];
++			/* Whenever --command-line or --append used, "kexec" is copied */
++			argc = 1;
++			/* Parse the offset */
++			while (ptr && (ARGV_MAX_ARGS > argc)) {
++				*ptr = '\0';
++				if (ptr[1] != ' ' && ptr[1] != '\0') {
++					int offt = (int)(ptr - str + 1);
++					kexec_argv[argc] = (int)kbuf + offt;
++					argc++;
++				}
++				ptr = strchr(ptr + 1, ' ');
++			}
++			if (argc > 1) {
++				/* Copy to kernel space */
++				copy_from_user(kbuf, (char *)image->segment[i].buf, image->segment[i].bufsz);
++				fw_arg0 = kexec_args[0] = argc;
++			}
++			break;
++		}
++	}
++
++	pr_info("argc = %lu\n", kexec_args[0]);
++	for (i = 0; i < kexec_args[0]; i++)
++		pr_info("argv[%d] = %p, %s\n", i, (char *)kexec_argv[i], (char *)kexec_argv[i]);
++
++	return 0;
++}
++
+ int
+ machine_kexec_prepare(struct kimage *kimage)
+ {
+@@ -45,6 +96,7 @@ machine_kexec_prepare(struct kimage *kim
+ 	 * This can be overrided by _machine_kexec_prepare().
+ 	 */
+ 	machine_kexec_init_args();
++	machine_kexec_pass_args(kimage);
+ 
+ 	if (_machine_kexec_prepare)
+ 		return _machine_kexec_prepare(kimage);