From: Lennert Buytenhek <[email protected]> On the Cirrus Logic ep93xx, system RAM isn't one nice physically contiguous region as it is on most SoCs, but it is spread out over between one and four memory banks.
What's worse, RAM doesn't necessarily start at any fixed physical memory location. The start of RAM (PHYS_OFFSET) is not only board- specific, but on some boards also depends on jumper settings (whether async or sync boot mode is selected.) The attached patch adds the RUNTIME_PHYS_OFFSET config option, which, if selected, turns PHYS_OFFSET into a variable which is determined and set by __create_page_tables by looking at the current pc. This allows booting a single kernel image on all the different flavors of ep93xx boards. If the option isn't selected, there's zero impact. Signed-off-by: Lennert Buytenhek <[email protected]> Signed-off-by: Steve Chen <[email protected]> Signed-off-by: Mark A. Greer <[email protected]> --- arch/arm/Kconfig | 4 +++ arch/arm/boot/compressed/Makefile | 9 ++---- arch/arm/boot/compressed/head.S | 6 ++++ arch/arm/include/asm/memory.h | 8 ++++++ arch/arm/kernel/head.S | 38 +++++++++++++++++++-------- arch/arm/kernel/setup.c | 14 +++++++++- arch/arm/mach-ep93xx/Makefile.boot | 1 - arch/arm/mach-ep93xx/include/mach/memory.h | 2 + 8 files changed, 63 insertions(+), 19 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 9bf3cb0..4043f02 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -188,6 +188,9 @@ config VECTORS_BASE help The base address of exception vectors. +config RUNTIME_PHYS_OFFSET + bool + source "init/Kconfig" source "kernel/Kconfig.freezer" @@ -272,6 +275,7 @@ config ARCH_EP93XX select HAVE_CLK select COMMON_CLKDEV select ARCH_REQUIRE_GPIOLIB + select RUNTIME_PHYS_OFFSET help This enables support for the Cirrus EP93xx series of CPUs. diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index fbe5eef..b0d7771 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -74,13 +74,10 @@ endif EXTRA_CFLAGS := -fpic -fno-builtin EXTRA_AFLAGS := -Wa,-march=all -# Supply ZRELADDR, INITRD_PHYS and PARAMS_PHYS to the decompressor via -# linker symbols. We only define initrd_phys and params_phys if the -# machine class defined the corresponding makefile variable. +# Supply ZRELADDR and PARAMS_PHYS to the decompressor via linker +# symbols. We only define params_phys if the machine class defined +# the corresponding makefile variable. LDFLAGS_vmlinux := --defsym zreladdr=$(ZRELADDR) -ifneq ($(INITRD_PHYS),) -LDFLAGS_vmlinux += --defsym initrd_phys=$(INITRD_PHYS) -endif ifneq ($(PARAMS_PHYS),) LDFLAGS_vmlinux += --defsym params_phys=$(PARAMS_PHYS) endif diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index 77d6142..e19623c 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -156,6 +156,12 @@ not_angel: .text adr r0, LC0 ldmia r0, {r1, r2, r3, r4, r5, r6, ip, sp} +#ifdef CONFIG_RUNTIME_PHYS_OFFSET + and r10, pc, #0xf0000000 @ fix up zreladdr + and r4, r4, #0x0fffffff + add r4, r4, r10 +#endif + subs r0, r0, r1 @ calculate the delta offset @ if delta is zero, we are diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h index 0202a7c..04be0b5 100644 --- a/arch/arm/include/asm/memory.h +++ b/arch/arm/include/asm/memory.h @@ -63,6 +63,14 @@ */ #define IOREMAP_MAX_ORDER 24 +/* + * PHYS_OFFSET determined at run time? + */ +#if defined(CONFIG_RUNTIME_PHYS_OFFSET) && !defined(__ASSEMBLY__) +extern unsigned long phys_offset; +#define PHYS_OFFSET (phys_offset) +#endif + #else /* CONFIG_MMU */ /* diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 21e17dc..9f70d0a 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -22,12 +22,13 @@ #include <asm/thread_info.h> #include <asm/system.h> +#ifndef CONFIG_RUNTIME_PHYS_OFFSET #if (PHYS_OFFSET & 0x001fffff) #error "PHYS_OFFSET must be at an even 2MiB boundary!" #endif +#endif #define KERNEL_RAM_VADDR (PAGE_OFFSET + TEXT_OFFSET) -#define KERNEL_RAM_PADDR (PHYS_OFFSET + TEXT_OFFSET) /* @@ -44,8 +45,8 @@ .globl swapper_pg_dir .equ swapper_pg_dir, KERNEL_RAM_VADDR - 0x4000 - .macro pgtbl, rd - ldr \rd, =(KERNEL_RAM_PADDR - 0x4000) + .macro pgtbl, rd, phys_offset + add \rd, \phys_offset, #(TEXT_OFFSET - 0x4000) .endm #ifdef CONFIG_XIP_KERNEL @@ -210,9 +211,26 @@ ENDPROC(__turn_mmu_on) * Returns: * r0, r3, r6, r7 corrupted * r4 = physical page table address + * r5 = PHYS_OFFSET */ __create_page_tables: - pgtbl r4 @ page table address +#ifdef CONFIG_RUNTIME_PHYS_OFFSET + adr r5, stext + sub r5, r5, #TEXT_OFFSET @ r5 = phys_offset + ldr r4, =0xfff00000 + and r5, r5, r4 + + ldr r4, =(phys_offset - PAGE_OFFSET) + add r4, r4, r5 + str r5, [r4] @ save phys_offset +#else + mov r5, #(PHYS_OFFSET & 0xff000000) + .if (PHYS_OFFSET & 0x00f00000) + orr r5, r5, #(PHYS_OFFSET & 0x00f00000) + .endif +#endif + + pgtbl r4, r5 @ r4 = page table address /* * Clear the 16K level 1 swapper page table @@ -257,10 +275,11 @@ __create_page_tables: /* * Map some ram to cover our .data and .bss areas. */ - orr r3, r7, #(KERNEL_RAM_PADDR & 0xff000000) - .if (KERNEL_RAM_PADDR & 0x00f00000) - orr r3, r3, #(KERNEL_RAM_PADDR & 0x00f00000) + add r3, r5, #(TEXT_OFFSET & 0xff000000) @ r5 = PHYS_OFFSET + .if (TEXT_OFFSET & 0x00f00000) + add r3, r3, #(TEXT_OFFSET & 0x00f00000) .endif + orr r3, r3, r7 add r0, r4, #(KERNEL_RAM_VADDR & 0xff000000) >> 18 str r3, [r0, #(KERNEL_RAM_VADDR & 0x00f00000) >> 18]! ldr r6, =(_end - 1) @@ -276,10 +295,7 @@ __create_page_tables: * Then map first 1MB of ram in case it contains our boot params. */ add r0, r4, #PAGE_OFFSET >> 18 - orr r6, r7, #(PHYS_OFFSET & 0xff000000) - .if (PHYS_OFFSET & 0x00f00000) - orr r6, r6, #(PHYS_OFFSET & 0x00f00000) - .endif + orr r6, r7, r5 str r6, [r0] #ifdef CONFIG_DEBUG_LL diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 7049815..99c2a53 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -63,6 +63,16 @@ __setup("fpe=", fpe_setup); extern void paging_init(struct machine_desc *desc); extern void reboot_setup(char *str); +#ifdef CONFIG_RUNTIME_PHYS_OFFSET +/* + * The assignment is here solely to prevent this variable from ending + * up in bss. As the early startup code writes to it, we don't want it + * to be zeroed again later. + */ +unsigned long phys_offset = 0xdeadbeef; +EXPORT_SYMBOL(phys_offset); +#endif + unsigned int processor_id; EXPORT_SYMBOL(processor_id); unsigned int __machine_arch_type; @@ -663,7 +673,7 @@ static struct init_tags { { tag_size(tag_core), ATAG_CORE }, { 1, PAGE_SIZE, 0xff }, { tag_size(tag_mem32), ATAG_MEM }, - { MEM_SIZE, PHYS_OFFSET }, + { MEM_SIZE, 0 }, { 0, ATAG_NONE } }; @@ -684,6 +694,8 @@ void __init setup_arch(char **cmdline_p) struct machine_desc *mdesc; char *from = default_command_line; + init_tags.mem.start = PHYS_OFFSET; + setup_processor(); mdesc = setup_machine(machine_arch_type); machine_name = mdesc->name; diff --git a/arch/arm/mach-ep93xx/Makefile.boot b/arch/arm/mach-ep93xx/Makefile.boot index d5561ad..574a4aa 100644 --- a/arch/arm/mach-ep93xx/Makefile.boot +++ b/arch/arm/mach-ep93xx/Makefile.boot @@ -1,2 +1 @@ zreladdr-y := 0x00008000 -params_phys-y := 0x00000100 diff --git a/arch/arm/mach-ep93xx/include/mach/memory.h b/arch/arm/mach-ep93xx/include/mach/memory.h index 5c80c3c..66e3b68 100644 --- a/arch/arm/mach-ep93xx/include/mach/memory.h +++ b/arch/arm/mach-ep93xx/include/mach/memory.h @@ -5,6 +5,8 @@ #ifndef __ASM_ARCH_MEMORY_H #define __ASM_ARCH_MEMORY_H +#ifndef CONFIG_RUNTIME_PHYS_OFFSET #define PHYS_OFFSET UL(0x00000000) +#endif #endif -- 1.6.0.3 _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
