Add code necessary for correct initialization of exception vector table when MMU is disabled.
Note: Please be aware that non ARMv7 implementation of this functionality was not fully tested due to the lack of any such hardware. It should theoretically work, but only testing that I did was to test place_vector_table() failure path (the best I could do on a i.MX6) Signed-off-by: Andrey Smirnov <[email protected]> --- arch/arm/cpu/Makefile | 6 +++ arch/arm/cpu/no-mmu.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 126 insertions(+) create mode 100644 arch/arm/cpu/no-mmu.c diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile index 418bcab..f708e8f 100644 --- a/arch/arm/cpu/Makefile +++ b/arch/arm/cpu/Makefile @@ -11,6 +11,12 @@ obj-$(CONFIG_CMD_ARM_MMUINFO) += mmuinfo.o obj-$(CONFIG_OFDEVICE) += dtb.o obj-$(CONFIG_MMU) += mmu.o cache.o mmu-early.o pbl-$(CONFIG_MMU) += mmu-early.o + +ifeq ($(CONFIG_MMU),) +obj-y += no-mmu.o +pbl-y += no-mmu.o +endif + obj-$(CONFIG_CPU_32v4T) += cache-armv4.o pbl-$(CONFIG_CPU_32v4T) += cache-armv4.o obj-$(CONFIG_CPU_32v5) += cache-armv5.o diff --git a/arch/arm/cpu/no-mmu.c b/arch/arm/cpu/no-mmu.c new file mode 100644 index 0000000..591cc2c --- /dev/null +++ b/arch/arm/cpu/no-mmu.c @@ -0,0 +1,120 @@ +/* + * Copyright (c) 2015 Zodiac Inflight Innovation + * Author: Andrey Smirnov <[email protected]> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#define pr_fmt(fmt) "nommu: " fmt + +#include <common.h> +#include <dma-dir.h> +#include <init.h> +#include <mmu.h> +#include <errno.h> +#include <linux/sizes.h> +#include <asm/memory.h> +#include <asm/barebox-arm.h> +#include <asm/system.h> +#include <asm/cache.h> +#include <memory.h> +#include <asm/system_info.h> +#include <debug_ll.h> + + +#define __exceptions_size (__exceptions_stop - __exceptions_start) + +#if __LINUX_ARM_ARCH__ >= 7 + +static int nommu_v7_vectors_init(void) +{ + void *vectors; + u32 cr; + + /* + High vectors cannot be re-mapped, so we have to use normal + vectors + */ + cr = get_cr(); + cr &= ~CR_V; + set_cr(cr); + + arm_fixup_vectors(); + + vectors = xmemalign(PAGE_SIZE, PAGE_SIZE); + memset(vectors, 0, PAGE_SIZE); + memcpy(vectors, __exceptions_start, __exceptions_size); + + set_vbar((unsigned int)vectors); + + return 0; +} +mmu_initcall(nommu_v7_vectors_init); + +#else + +#warning "This code has seen only rudimentary testing (only failure path). Proceed with caution" + +static struct resource *place_vector_table(void) +{ + int i; + struct resource *vectors = NULL; + resource_size_t addr[2] = { 0x00000000, 0xFFFF0000 }; + + for (i = 0; i < ARRAY_SIZE(addr); i++) { + vectors = request_sdram_region("exceptions", + addr[i], + __exceptions_size); + if (vectors) + break; + } + + return vectors; +} + +static int nommu_v4_vectors_init(void) +{ + u32 cr; + struct resource *vectors; + + vectors = place_vector_table(); + if (!vectors) { + pr_crit("Critical Error: Can't place exception vector table\n"); + return 0; + } + + cr = get_cr(); + + if (vectors->start) { + cr |= CR_V; + set_cr(cr); + + if (!(get_cr() & CR_V)) { + pr_crit("Critical Error: " + "High vector table is unavailble\n"); + release_sdram_region(vectors); + return 0; + } + } else { + cr &= ~CR_V; + set_cr(cr); + } + + arm_fixup_vectors(); + + memcpy((void *)vectors->start, + __exceptions_start, resource_size(vectors)); + + return 0; +} +mmu_initcall(nommu_v4_vectors_init); + +#endif -- 2.5.0 _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox
