[PATCH 6a] ARM: support big/little endian switching in "bootz".
Krzysztof Halasa
khc at pm.waw.pl
Tue Dec 21 19:53:29 EST 2010
Signed-off-by: Krzysztof Hałasa <khc at pm.waw.pl>
diff --git a/arch/arm/cpu/Kconfig b/arch/arm/cpu/Kconfig
index 3572a1f..73ee115 100644
--- a/arch/arm/cpu/Kconfig
+++ b/arch/arm/cpu/Kconfig
@@ -73,6 +73,15 @@ config CPU_BIG_ENDIAN
port must properly enable any big-endian related features
of your chipset/board/processor.
+config BOOTZ_ENDIANNESS_SWITCH
+ bool "Support switching of Linux kernel endianness"
+ help
+ Say Y here if you need to switch CPU endianness before running
+ Linux kernel, e.g. if you want big-endian Barebox to run
+ little-endian Linux.
+
+ Currently implemented only in "bootz" command.
+
config ARCH_HAS_L2X0
bool
diff --git a/arch/arm/lib/armlinux.c b/arch/arm/lib/armlinux.c
index f826da6..6462013 100644
--- a/arch/arm/lib/armlinux.c
+++ b/arch/arm/lib/armlinux.c
@@ -41,6 +41,7 @@
#include <asm/setup.h>
#include <asm/barebox-arm.h>
#include <asm/armlinux.h>
+#include <asm/system.h>
static struct tag *params;
static int armlinux_architecture = 0;
@@ -85,9 +86,10 @@ static void setup_memory_tags(void)
}
}
-static void setup_commandline_tag(const char *commandline)
+static void setup_commandline_tag(const char *commandline, int swap)
{
const char *p;
+ size_t words;
if (!commandline)
return;
@@ -102,12 +104,20 @@ static void setup_commandline_tag(const char *commandline)
if (*p == '\0')
return;
+ words = (strlen(p) + 1 /* NUL */ + 3 /* round up */) >> 2;
params->hdr.tag = ATAG_CMDLINE;
- params->hdr.size =
- (sizeof (struct tag_header) + strlen(p) + 1 + 4) >> 2;
+ params->hdr.size = (sizeof(struct tag_header) >> 2) + words;
strcpy(params->u.cmdline.cmdline, p);
+#ifdef CONFIG_BOOTZ_ENDIANNESS_SWITCH
+ if (swap) {
+ u32 *cmd = (u32 *)params->u.cmdline.cmdline;
+ while (words--)
+ cmd[words] = swab32(cmd[words]);
+ }
+#endif
+
params = tag_next(params);
}
@@ -156,13 +166,13 @@ static void setup_end_tag (void)
params->hdr.size = 0;
}
-static void setup_tags(struct image_data *data)
+static void setup_tags(struct image_data *data, int swap)
{
const char *commandline = getenv("bootargs");
setup_start_tag();
setup_memory_tags();
- setup_commandline_tag(commandline);
+ setup_commandline_tag(commandline, swap);
if (data && data->initrd)
setup_initrd_tag (&data->initrd->header);
@@ -231,7 +241,7 @@ static int do_bootm_linux(struct image_data *data)
debug("## Transferring control to Linux (at address 0x%p) ...\n",
theKernel);
- setup_tags(data);
+ setup_tags(data, 0);
if (relocate_image(data->os, (void *)image_get_load(os_header)))
return -1;
@@ -290,18 +300,21 @@ late_initcall(armlinux_register_image_handler);
#ifdef CONFIG_CMD_BOOTZ
struct zimage_header {
- u32 unsused[9];
+ u32 unused[9];
u32 magic;
u32 start;
u32 end;
};
+#define ZIMAGE_MAGIC 0x016F2818
+
static int do_bootz(struct command *cmdtp, int argc, char *argv[])
{
void (*theKernel)(int zero, int arch, void *params);
- int fd, ret;
+ int fd, ret, swap = 0;
struct zimage_header header;
void *zimage;
+ u32 end;
if (argc != 2) {
barebox_cmd_usage(cmdtp);
@@ -320,27 +333,53 @@ static int do_bootz(struct command *cmdtp, int argc, char *argv[])
goto err_out;
}
- if (header.magic != 0x016f2818) {
+ switch (header.magic) {
+#ifdef CONFIG_BOOTZ_ENDIANNESS_SWITCH
+ case swab32(ZIMAGE_MAGIC):
+ swap = 1;
+ /* fall through */
+#endif
+ case ZIMAGE_MAGIC:
+ break;
+ default:
printf("invalid magic 0x%08x\n", header.magic);
goto err_out;
}
- zimage = xmalloc(header.end);
+ end = header.end;
+
+ if (swap)
+ end = swab32(end);
+
+ zimage = xmalloc(end);
memcpy(zimage, &header, sizeof(header));
- ret = read(fd, zimage + sizeof(header), header.end - sizeof(header));
- if (ret < header.end - sizeof(header)) {
+ ret = read(fd, zimage + sizeof(header), end - sizeof(header));
+ if (ret < end - sizeof(header)) {
printf("could not read %s\n", argv[1]);
goto err_out1;
}
+ if (swap) {
+ void *ptr;
+ for (ptr = zimage; ptr < zimage + end; ptr += 4)
+ *(u32 *)ptr = swab32(*(u32 *)ptr);
+ }
+
theKernel = zimage;
- printf("loaded zImage from %s with size %d\n", argv[1], header.end);
+ printf("loaded zImage from %s with size %d\n", argv[1], end);
- setup_tags(NULL);
+ setup_tags(NULL, swap);
shutdown_barebox();
+ if (swap) {
+ u32 reg;
+ __asm__ __volatile__("mrc p15, 0, %0, c1, c0" : "=r" (reg));
+ reg ^= CR_B; /* swap big-endian flag */
+ __asm__ __volatile__("mcr p15, 0, %0, c1, c0" :: "r" (reg));
+ }
+
theKernel(0, armlinux_architecture, armlinux_bootparams);
return 0;
@@ -382,7 +421,7 @@ static int do_bootu(struct command *cmdtp, int argc, char *argv[])
if (!theKernel)
theKernel = (void *)simple_strtoul(argv[1], NULL, 0);
- setup_tags(NULL);
+ setup_tags(NULL, 0);
shutdown_barebox();
theKernel(0, armlinux_architecture, armlinux_bootparams);
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