m68knommu: add uboot commandline argument passing support
authorLennart Sorensen <lsorense@csclub.uwaterloo.ca>
Fri, 18 Sep 2009 17:49:36 +0000 (13:49 -0400)
committerGreg Ungerer <gerg@goober.(none)>
Fri, 4 Dec 2009 01:45:30 +0000 (11:45 +1000)
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@csclub.uwaterloo.ca>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
arch/m68knommu/Kconfig
arch/m68knommu/kernel/setup.c
arch/m68knommu/platform/coldfire/head.S

index e2201b90aa22a2dbbf136e65bb6821f65f934bb7..064f5913db1a7c2122dd902c01f558b0484ab4cf 100644 (file)
@@ -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
index 5c2bb3eeaaa2ec98ecdead8e7a2f03a3d9d51e34..ba92b90d5fbc81e7fd7f8cb3fad54b13461ac1f0 100644 (file)
@@ -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>
@@ -52,7 +54,6 @@ void (*mach_reset)(void);
 void (*mach_halt)(void);
 void (*mach_power_off)(void);
 
-
 #ifdef CONFIG_M68000
        #define CPU "MC68000"
 #endif
@@ -111,6 +112,69 @@ void (*mach_power_off)(void);
 extern int _stext, _etext, _sdata, _edata, _sbss, _ebss, _end;
 extern int _ramstart, _ramend;
 
+#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(KERN_INFO "initrd at 0x%lx:0x%lx\n",
+                       initrd_start, initrd_end);
+       }
+#endif /* if defined(CONFIG_BLK_DEV_INITRD) */
+}
+#endif /* #if defined(CONFIG_UBOOT) */
+
 void __init setup_arch(char **cmdline_p)
 {
        int bootmap_size;
@@ -128,7 +192,24 @@ 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");
 
@@ -204,6 +285,13 @@ 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.
         */
index 2b0d73c0cc328c6bb975a9204c731d6b311b4c9d..4b91aa24eb00a6ec95510cfd88b210f99b8dcc05 100644 (file)
 .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