| Message ID | 1308632955-11070-5-git-send-email-nico@fluxnic.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jun 21, 2011 at 01:09:15AM -0400, Nicolas Pitre wrote: > From: Nicolas Pitre <nicolas.pitre@linaro.org> > > Some old bootloaders can't be updated to a device tree capable one, > yet they provide ATAGs with memory configuration, the ramdisk address, > the kernel cmdline string, etc. To allow a device tree enabled > kernel to be used with such bootloaders, it is necessary to convert those > ATAGs into FDT properties and fold them into the DTB appended to zImage. > > Currently the following ATAGs are converted: > > ATAG_CMDLINE > ATAG_MEM (up to 8 memory regions) > ATAG_INITRD2 > > If the corresponding information already exists in the appended DTB, it > is replaced, otherwise the required node is created to hold it. > > The code looks for ATAGs at the location pointed by the value of r2 upon > entry into the zImage code. If no ATAGs are found there, an attempt at > finding ATAGs at the typical 0x100 offset from start of RAM is made. > Otherwise the DTB is left unchanged. > > Thisstarted from an older patch from John Bonesio <bones@secretlab.ca>, > with contributions from David Brown <davidb@codeaurora.org>. > > Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> > --- With this patch applied, I saw nothing coming from kernel on imx51 babbage serial port.
On Tue, Jun 21 2011, Shawn Guo wrote: > On Tue, Jun 21, 2011 at 01:09:15AM -0400, Nicolas Pitre wrote: >> From: Nicolas Pitre <nicolas.pitre@linaro.org> >> >> Some old bootloaders can't be updated to a device tree capable one, >> yet they provide ATAGs with memory configuration, the ramdisk address, >> the kernel cmdline string, etc. To allow a device tree enabled >> kernel to be used with such bootloaders, it is necessary to convert those >> ATAGs into FDT properties and fold them into the DTB appended to zImage. >> >> Currently the following ATAGs are converted: >> >> ATAG_CMDLINE >> ATAG_MEM (up to 8 memory regions) >> ATAG_INITRD2 >> >> If the corresponding information already exists in the appended DTB, it >> is replaced, otherwise the required node is created to hold it. >> >> The code looks for ATAGs at the location pointed by the value of r2 upon >> entry into the zImage code. If no ATAGs are found there, an attempt at >> finding ATAGs at the typical 0x100 offset from start of RAM is made. >> Otherwise the DTB is left unchanged. >> >> Thisstarted from an older patch from John Bonesio <bones@secretlab.ca>, >> with contributions from David Brown <davidb@codeaurora.org>. >> >> Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org> >> --- > > With this patch applied, I saw nothing coming from kernel on imx51 > babbage serial port. Can you try seeing if it works with padding in the DTB that you are using? Right now, I'm using something like: / { ... memory { reg = <0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0>; }; chosen { bootargs = " "; /* Enough for arg */ linux,initrd-start = <0>; linux,initrd-end = <0>; }; }; I get problems if the fdt code tries to expand the tree, even if I add padding when running the dtc (I've tried -p 1024). Hopefully, I'll get some time today to try and figure out what is going on. David
On Mon, Jun 20 2011, Nicolas Pitre wrote: > +void *memmove(void *__dest, __const void *__src, size_t __n) > +{ > + unsigned char *d = __dest; > + const unsigned char *s = __src; > + > + if (__dest == __src) > + return __dest; > + > + if (__dest < __src) > + return memcpy(__dest, __src, __n); > + > + while (--__n >= 0) > + d[__n] = s[__n]; > + > + return __dest; > +} Ahh, found it. size_t is unsigned, so the while loop never terminates. Something like: for (; __n; __n--) d[__n] = s[__n]; makes that work for me. This allows me to not need to pad or have any of the chosen attributes. I do need to have a memory attribute, however, and I'll see if I can figure out what is happening there. Fun debugging when the loop overwrites the code itself, but it keeps working because it is in the cache. David
On Tue, Jun 21 2011, David Brown wrote: > On Mon, Jun 20 2011, Nicolas Pitre wrote: > >> +void *memmove(void *__dest, __const void *__src, size_t __n) >> +{ >> + unsigned char *d = __dest; >> + const unsigned char *s = __src; >> + >> + if (__dest == __src) >> + return __dest; >> + >> + if (__dest < __src) >> + return memcpy(__dest, __src, __n); >> + >> + while (--__n >= 0) >> + d[__n] = s[__n]; >> + >> + return __dest; >> +} > > Ahh, found it. size_t is unsigned, so the while loop never terminates. > Something like: > > for (; __n; __n--) > d[__n] = s[__n]; Ugh. How about if I don't replace a broken version with a different broken version. while (__n) { __n--; d[__n] = s[__n]; } Now, I don't need any extra fields in my DTB, and it correctly inserts the ATAG values. David
On Jun 21, 2011, at 5:13 PM, David Brown wrote: > On Tue, Jun 21 2011, David Brown wrote: > >> On Mon, Jun 20 2011, Nicolas Pitre wrote: >> >>> +void *memmove(void *__dest, __const void *__src, size_t __n) >>> +{ >>> + unsigned char *d = __dest; >>> + const unsigned char *s = __src; >>> + >>> + if (__dest == __src) >>> + return __dest; >>> + >>> + if (__dest < __src) >>> + return memcpy(__dest, __src, __n); >>> + >>> + while (--__n >= 0) >>> + d[__n] = s[__n]; >>> + >>> + return __dest; >>> +} >> >> Ahh, found it. size_t is unsigned, so the while loop never terminates. >> Something like: >> >> for (; __n; __n--) >> d[__n] = s[__n]; > > Ugh. How about if I don't replace a broken version with a different > broken version. > > while (__n) { > __n--; > d[__n] = s[__n]; > } > > Now, I don't need any extra fields in my DTB, and it correctly inserts > the ATAG values. while (__n--) d[__n] = s[__n]; does the same thing, and is more readable (and does the same thing as the original while()) Warner
On Tue, 21 Jun 2011, David Brown wrote: > On Tue, Jun 21 2011, David Brown wrote: > > > On Mon, Jun 20 2011, Nicolas Pitre wrote: > > > >> +void *memmove(void *__dest, __const void *__src, size_t __n) > >> +{ > >> + unsigned char *d = __dest; > >> + const unsigned char *s = __src; > >> + > >> + if (__dest == __src) > >> + return __dest; > >> + > >> + if (__dest < __src) > >> + return memcpy(__dest, __src, __n); > >> + > >> + while (--__n >= 0) > >> + d[__n] = s[__n]; > >> + > >> + return __dest; > >> +} > > > > Ahh, found it. size_t is unsigned, so the while loop never terminates. > > Something like: > > > > for (; __n; __n--) > > d[__n] = s[__n]; > > Ugh. How about if I don't replace a broken version with a different > broken version. Blah. I'll try to fetch the generic version in lib/string.c instead of duplicating that stuff. Thanks for investigating. I only was able to compile-test the thing so far. ;-) Nicolas
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 66b7d1e..166bd2a 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1735,6 +1735,17 @@ config ARM_APPENDED_DTB (dtb) appended to zImage (e.g. cat zImage <filename>.dtb > zImage_w_dtb). +config ARM_ATAG_DTB_COMPAT + bool "Supplement the appended DTB with traditional ATAG information" + depends on ARM_APPENDED_DTB + help + Some old bootloaders can't be updated to a DTB capable one, yet + they provide ATAGs with memory configuration, the ramdisk address, + the kernel cmdline string, etc. To allow a device tree enabled + kernel to be used with such bootloaders, this option allows + zImage to extract the information from the ATAG list and store it + at run time into the appended DTB. + config CMDLINE string "Default kernel command string" default "" diff --git a/arch/arm/boot/compressed/.gitignore b/arch/arm/boot/compressed/.gitignore index c602896..e0936a1 100644 --- a/arch/arm/boot/compressed/.gitignore +++ b/arch/arm/boot/compressed/.gitignore @@ -5,3 +5,12 @@ piggy.lzo piggy.lzma vmlinux vmlinux.lds + +# borrowed libfdt files +fdt.c +fdt.h +fdt_ro.c +fdt_rw.c +fdt_wip.c +libfdt.h +libfdt_internal.h diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index 48bead9..4b94995 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -83,19 +83,36 @@ suffix_$(CONFIG_KERNEL_GZIP) = gzip suffix_$(CONFIG_KERNEL_LZO) = lzo suffix_$(CONFIG_KERNEL_LZMA) = lzma +# libfdt files for the ATAG compatibility mode + +libfdt := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c +libfdt_hdrs := fdt.h libfdt.h libfdt_internal.h + +libfdt_objs := $(addsuffix .o, $(basename $(libfdt))) + +$(addprefix $(obj)/,$(libfdt) $(libfdt_hdrs)): $(obj)/%: $(srctree)/scripts/dtc/libfdt/% + $(call if_changed,shipped) + +$(addprefix $(obj)/,$(libfdt_objs) atags_to_fdt.o): \ + $(addprefix $(obj)/,$(libfdt_hdrs)) + +ifeq ($(CONFIG_ARM_ATAG_DTB_COMPAT),y) +OBJS += $(libfdt_objs) atags_to_fdt.o +endif + targets := vmlinux vmlinux.lds \ piggy.$(suffix_y) piggy.$(suffix_y).o \ font.o font.c head.o misc.o $(OBJS) # Make sure files are removed during clean -extra-y += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S +extra-y += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S $(libfdt) $(libfdt_hdrs) ifeq ($(CONFIG_FUNCTION_TRACER),y) ORIG_CFLAGS := $(KBUILD_CFLAGS) KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS)) endif -ccflags-y := -fpic -fno-builtin +ccflags-y := -fpic -fno-builtin -I$(src) asflags-y := -Wa,-march=all # Supply kernel BSS size to the decompressor via a linker symbol. @@ -118,7 +135,7 @@ LDFLAGS_vmlinux += -X LDFLAGS_vmlinux += -T # For __aeabi_uidivmod -lib1funcs = $(obj)/lib1funcs.o +lib1funcs = $(obj)/lib1funcs.o $(obj)/../../lib/lib.a $(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE $(call cmd,shipped) diff --git a/arch/arm/boot/compressed/atags_to_fdt.c b/arch/arm/boot/compressed/atags_to_fdt.c new file mode 100644 index 0000000..d79afd7 --- /dev/null +++ b/arch/arm/boot/compressed/atags_to_fdt.c @@ -0,0 +1,97 @@ +#include <asm/setup.h> +#include <libfdt.h> + +static int node_offset(void *fdt, const char *node_path) +{ + int offset = fdt_path_offset(fdt, node_path); + if (offset == -FDT_ERR_NOTFOUND) + offset = fdt_add_subnode(fdt, 0, node_path); + return offset; +} + +static int setprop(void *fdt, const char *node_path, const char *property, + uint32_t *val_array, int size) +{ + int offset = node_offset(fdt, node_path); + if (offset < 0) + return offset; + return fdt_setprop(fdt, offset, property, val_array, size); +} + +static int setprop_string(void *fdt, const char *node_path, + const char *property, const char *string) +{ + int offset = node_offset(fdt, node_path); + if (offset < 0) + return offset; + return fdt_setprop_string(fdt, offset, property, string); +} + +static int setprop_cell(void *fdt, const char *node_path, + const char *property, uint32_t val) +{ + int offset = node_offset(fdt, node_path); + if (offset < 0) + return offset; + return fdt_setprop_cell(fdt, offset, property, val); +} + +/* + * Convert and fold provided ATAGs into the provided FDT. + * + * REturn values: + * = 0 -> pretend success + * = 1 -> bad ATAG (may retry with another possible ATAG pointer) + * < 0 -> error from libfdt + */ +int atags_to_fdt(void *atag_list, void *fdt, int total_space) +{ + struct tag *atag = atag_list; + uint32_t mem_reg_property[16]; + int memcount = 0; + int ret; + + /* make sure we've got an aligned pointer */ + if ((u32)atag_list & 0x3) + return 1; + + /* if we get a DTB here we're done already */ + if (*(u32 *)atag_list == fdt32_to_cpu(FDT_MAGIC)) + return 0; + + /* validate the ATAG */ + if (atag->hdr.tag != ATAG_CORE || + (atag->hdr.size != tag_size(tag_core) && + atag->hdr.size != 2)) + return 1; + + /* let's give it all the room it could need */ + ret = fdt_open_into(fdt, fdt, total_space); + if (ret < 0) + return ret; + + for_each_tag(atag, atag_list) { + if (atag->hdr.tag == ATAG_CMDLINE) { + setprop_string(fdt, "/chosen", "bootargs", + atag->u.cmdline.cmdline); + } else if (atag->hdr.tag == ATAG_MEM) { + if (memcount >= sizeof(mem_reg_property)/sizeof(uint32_t)) + continue; + mem_reg_property[memcount++] = cpu_to_fdt32(atag->u.mem.start); + mem_reg_property[memcount++] = cpu_to_fdt32(atag->u.mem.size); + } else if (atag->hdr.tag == ATAG_INITRD2) { + uint32_t initrd_start, initrd_size; + initrd_start = atag->u.initrd.start; + initrd_size = atag->u.initrd.size; + setprop_cell(fdt, "/chosen", "linux,initrd-start", + initrd_start); + setprop_cell(fdt, "/chosen", "linux,initrd-end", + initrd_start + initrd_size); + } + } + + if (memcount) + setprop(fdt, "/memory", "reg", mem_reg_property, 4*memcount); + + return fdt_pack(fdt); +} diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index d4f8db2..6ca94d1 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -246,6 +246,38 @@ restart: adr r0, LC0 cmp lr, r1 bne dtb_check_done @ not found +#ifdef CONFIG_ARM_ATAG_DTB_COMPAT + /* + * OK... Let's do some funky business here. + * If we do have a DTB appended to zImage, and we do have + * an ATAG list around, we want the later to be translated + * and folded into the former here. To be on the safe side, + * let's temporarily move the stack away into the malloc + * area. No GOT fixup has occurred yet, but none of the + * code we're about to call uses any global variable. + */ + add sp, sp, #0x10000 + stmfd sp!, {r0-r3, ip, lr} + mov r0, r8 + mov r1, r6 + sub r2, sp, r6 + bl atags_to_fdt + + /* + * If returned value is 1, there is no ATAG at the location + * pointed by r8. Try the typical 0x100 offset from start + * of RAM and hope for the best. + */ + cmp r0, #1 + sub r0, r4, #(TEXT_OFFSET - 0x100) + mov r1, r6 + sub r2, sp, r6 + blne atags_to_fdt + + ldmfd sp!, {r0-r3, ip, lr} + sub sp, sp, #0x10000 +#endif + mov r8, r6 @ use the appended device tree /* diff --git a/arch/arm/boot/compressed/libfdt_env.h b/arch/arm/boot/compressed/libfdt_env.h new file mode 100644 index 0000000..1f4e718 --- /dev/null +++ b/arch/arm/boot/compressed/libfdt_env.h @@ -0,0 +1,15 @@ +#ifndef _ARM_LIBFDT_ENV_H +#define _ARM_LIBFDT_ENV_H + +#include <linux/types.h> +#include <linux/string.h> +#include <asm/byteorder.h> + +#define fdt16_to_cpu(x) be16_to_cpu(x) +#define cpu_to_fdt16(x) cpu_to_be16(x) +#define fdt32_to_cpu(x) be32_to_cpu(x) +#define cpu_to_fdt32(x) cpu_to_be32(x) +#define fdt64_to_cpu(x) be64_to_cpu(x) +#define cpu_to_fdt64(x) cpu_to_be64(x) + +#endif diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c index 832d372..535b14e 100644 --- a/arch/arm/boot/compressed/misc.c +++ b/arch/arm/boot/compressed/misc.c @@ -136,6 +136,58 @@ void *memcpy(void *__dest, __const void *__src, size_t __n) return __dest; } +void *memmove(void *__dest, __const void *__src, size_t __n) +{ + unsigned char *d = __dest; + const unsigned char *s = __src; + + if (__dest == __src) + return __dest; + + if (__dest < __src) + return memcpy(__dest, __src, __n); + + while (--__n >= 0) + d[__n] = s[__n]; + + return __dest; +} + +size_t strlen(const char *s) +{ + const char *sc; + + for (sc = s; *sc != '\0'; ++sc) + /* nothing */; + return sc - s; +} + +int memcmp(const void *cs, const void *ct, size_t count) +{ + const unsigned char *su1, *su2; + int res = 0; + + for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) + if ((res = *su1 - *su2) != 0) + break; + return res; +} + +int strcmp(const char *cs, const char *ct) +{ + unsigned char c1, c2; + + while (1) { + c1 = *cs++; + c2 = *ct++; + if (c1 != c2) + return c1 < c2 ? -1 : 1; + if (!c1) + break; + } + return 0; +} + /* * gzip declarations */