--- /dev/null
+Author: Adrian Panella <ianchi74@outlook.com>
+Date: Fri Jun 10 19:10:15 2016 -0500
+
+generic: Mangle bootloader's kernel arguments
+
+The command-line arguments provided by the boot loader will be
+appended to a new device tree property: bootloader-args.
+If there is a property "append-rootblock" in DT under /chosen
+and a root= option in bootloaders command line it will be parsed
+and added to DT bootargs with the form: <append-rootblock>XX.
+Only command line ATAG will be processed, the rest of the ATAGs
+sent by bootloader will be ignored.
+This is usefull in dual boot systems, to get the current root partition
+without afecting the rest of the system.
+
+
+Signed-off-by: Adrian Panella <ianchi74@outlook.com>
+
+--- a/arch/arm/Kconfig
++++ b/arch/arm/Kconfig
+@@ -1927,6 +1927,17 @@ config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEN
+ The command-line arguments provided by the boot loader will be
+ appended to the the device tree bootargs property.
+
++config ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
++ bool "Append rootblock parsing bootloader's kernel arguments"
++ help
++ The command-line arguments provided by the boot loader will be
++ appended to a new device tree property: bootloader-args.
++ If there is a property "append-rootblock" in DT under /chosen
++ and a root= option in bootloaders command line it will be parsed
++ and added to DT bootargs with the form: <append-rootblock>XX.
++ Only command line ATAG will be processed, the rest of the ATAGs
++ sent by bootloader will be ignored.
++
+ endchoice
+
+ config CMDLINE
+--- a/arch/arm/boot/compressed/atags_to_fdt.c
++++ b/arch/arm/boot/compressed/atags_to_fdt.c
+@@ -3,6 +3,8 @@
+
+ #if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND)
+ #define do_extend_cmdline 1
++#elif defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
++#define do_extend_cmdline 1
+ #else
+ #define do_extend_cmdline 0
+ #endif
+@@ -66,6 +68,59 @@ static uint32_t get_cell_size(const void
+ return cell_size;
+ }
+
++#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
++
++static char *append_rootblock(char *dest, const char *str, int len, void *fdt)
++{
++ char *ptr, *end;
++ char *root="root=";
++ int i, l;
++ const char *rootblock;
++
++ //ARM doesn't have __HAVE_ARCH_STRSTR, so search manually
++ ptr = str - 1;
++
++ do {
++ ptr++;
++ //first find an 'r' at the begining or after a space
++ do {
++ ptr = strchr(ptr, 'r');
++ if(!ptr) return dest;
++
++ } while (ptr != str && *(ptr-1) != ' ');
++
++ //then check for the rest
++ for(i = 1; i <= 4; i++)
++ if(*(ptr+i) != *(root+i)) break;
++
++ } while (i != 5);
++
++ end = strchr(ptr, ' ');
++ end = end ? (end - 1) : (strchr(ptr, 0) - 1);
++
++ //find partition number (assumes format root=/dev/mtdXX | /dev/mtdblockXX | yy:XX )
++ for( i = 0; end >= ptr && *end >= '0' && *end <= '9'; end--, i++);
++ ptr = end + 1;
++
++ /* if append-rootblock property is set use it to append to command line */
++ rootblock = getprop(fdt, "/chosen", "append-rootblock", &l);
++ if(rootblock != NULL) {
++ if(*dest != ' ') {
++ *dest = ' ';
++ dest++;
++ len++;
++ }
++ if (len + l + i <= COMMAND_LINE_SIZE) {
++ memcpy(dest, rootblock, l);
++ dest += l - 1;
++ memcpy(dest, ptr, i);
++ dest += i;
++ }
++ }
++ return dest;
++}
++#endif
++
+ static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline)
+ {
+ char cmdline[COMMAND_LINE_SIZE];
+@@ -85,12 +134,21 @@ static void merge_fdt_bootargs(void *fdt
+
+ /* and append the ATAG_CMDLINE */
+ if (fdt_cmdline) {
++
++#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
++ //save original bootloader args
++ //and append ubi.mtd with root partition number to current cmdline
++ setprop_string(fdt, "/chosen", "bootloader-args", fdt_cmdline);
++ ptr = append_rootblock(ptr, fdt_cmdline, len, fdt);
++
++#else
+ len = strlen(fdt_cmdline);
+ if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) {
+ *ptr++ = ' ';
+ memcpy(ptr, fdt_cmdline, len);
+ ptr += len;
+ }
++#endif
+ }
+ *ptr = '\0';
+
+@@ -147,7 +205,9 @@ int atags_to_fdt(void *atag_list, void *
+ else
+ setprop_string(fdt, "/chosen", "bootargs",
+ atag->u.cmdline.cmdline);
+- } else if (atag->hdr.tag == ATAG_MEM) {
++ }
++#ifndef CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
++ else if (atag->hdr.tag == ATAG_MEM) {
+ if (memcount >= sizeof(mem_reg_property)/4)
+ continue;
+ if (!atag->u.mem.size)
+@@ -186,6 +246,10 @@ int atags_to_fdt(void *atag_list, void *
+ setprop(fdt, "/memory", "reg", mem_reg_property,
+ 4 * memcount * memsize);
+ }
++#else
++
++ }
++#endif
+
+ return fdt_pack(fdt);
+ }
+--- a/init/main.c
++++ b/init/main.c
+@@ -88,6 +88,10 @@
+ #include <asm/sections.h>
+ #include <asm/cacheflush.h>
+
++#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
++#include <linux/of.h>
++#endif
++
+ static int kernel_init(void *);
+
+ extern void init_IRQ(void);
+@@ -585,6 +589,18 @@ asmlinkage __visible void __init start_k
+ page_alloc_init();
+
+ pr_notice("Kernel command line: %s\n", boot_command_line);
++
++#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
++ //Show bootloader's original command line for reference
++ if(of_chosen) {
++ const char *prop = of_get_property(of_chosen, "bootloader-args", NULL);
++ if(prop)
++ pr_notice("Bootloader command line (ignored): %s\n", prop);
++ else
++ pr_notice("Bootloader command line not present\n");
++ }
++#endif
++
+ parse_early_param();
+ after_dashes = parse_args("Booting kernel",
+ static_command_line, __start___param,
projects / openwrt / staging / florian.git / commitdiff