diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/mm/nommu.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c index dd3a6c6..0897d6b 100644 --- a/arch/arm/mm/nommu.c +++ b/arch/arm/mm/nommu.c @@ -8,6 +8,7 @@ #include <linux/pagemap.h> #include <linux/io.h> #include <linux/memblock.h> +#include <linux/kernel.h> #include <asm/cacheflush.h> #include <asm/sections.h> @@ -15,9 +16,257 @@ #include <asm/setup.h> #include <asm/traps.h> #include <asm/mach/arch.h> +#include <asm/cputype.h> +#include <asm/mpu.h> #include "mm.h" +#ifdef CONFIG_ARM_MPU +struct mpu_rgn_info mpu_rgn_info; + +/* Region number */ +static void rgnr_write(u32 v) +{ + asm("mcr p15, 0, %0, c6, c2, 0" : : "r" (v)); +} + +/* Data-side / unified region attributes */ + +/* Region access control register */ +static void dracr_write(u32 v) +{ + asm("mcr p15, 0, %0, c6, c1, 4" : : "r" (v)); +} + +/* Region size register */ +static void drsr_write(u32 v) +{ + asm("mcr p15, 0, %0, c6, c1, 2" : : "r" (v)); +} + +/* Region base address register */ +static void drbar_write(u32 v) +{ + asm("mcr p15, 0, %0, c6, c1, 0" : : "r" (v)); +} + +static u32 drbar_read(void) +{ + u32 v; + asm("mrc p15, 0, %0, c6, c1, 0" : "=r" (v)); + return v; +} +/* Optional instruction-side region attributes */ + +/* I-side Region access control register */ +static void iracr_write(u32 v) +{ + asm("mcr p15, 0, %0, c6, c1, 5" : : "r" (v)); +} + +/* I-side Region size register */ +static void irsr_write(u32 v) +{ + asm("mcr p15, 0, %0, c6, c1, 3" : : "r" (v)); +} + +/* I-side Region base address register */ +static void irbar_write(u32 v) +{ + asm("mcr p15, 0, %0, c6, c1, 1" : : "r" (v)); +} + +static unsigned long irbar_read(void) +{ + unsigned long v; + asm("mrc p15, 0, %0, c6, c1, 1" : "=r" (v)); + return v; +} + +/* MPU initialisation functions */ +void __init sanity_check_meminfo_mpu(void) +{ + int i; + struct membank *bank = meminfo.bank; + phys_addr_t phys_offset = PHYS_OFFSET; + phys_addr_t aligned_region_size, specified_mem_size, rounded_mem_size; + + /* Initially only use memory continuous from PHYS_OFFSET */ + if (bank_phys_start(&bank[0]) != phys_offset) + panic("First memory bank must be contiguous from PHYS_OFFSET"); + + /* Banks have already been sorted by start address */ + for (i = 1; i < meminfo.nr_banks; i++) { + if (bank[i].start <= bank_phys_end(&bank[0]) && + bank_phys_end(&bank[i]) > bank_phys_end(&bank[0])) { + bank[0].size = bank_phys_end(&bank[i]) - bank[0].start; + } else { + pr_notice("Ignoring RAM after 0x%.8lx. " + "First non-contiguous (ignored) bank start: 0x%.8lx\n", + (unsigned long)bank_phys_end(&bank[0]), + (unsigned long)bank_phys_start(&bank[i])); + break; + } + } + /* All contiguous banks are now merged in to the first bank */ + meminfo.nr_banks = 1; + specified_mem_size = bank[0].size; + + /* + * MPU has curious alignment requirements: Size must be power of 2, and + * region start must be aligned to the region size + */ + if (phys_offset != 0) + pr_info("PHYS_OFFSET != 0 => MPU Region size constrained by alignment requirements\n"); + + /* + * Maximum aligned region might overflow phys_addr_t if phys_offset is + * 0. Hence we keep everything below 4G until we take the smaller of + * the aligned_region_size and rounded_mem_size, one of which is + * guaranteed to be smaller than the maximum physical address. + */ + aligned_region_size = (phys_offset - 1) ^ (phys_offset); + /* Find the max power-of-two sized region that fits inside our bank */ + rounded_mem_size = (1 << __fls(bank[0].size)) - 1; + + /* The actual region size is the smaller of the two */ + aligned_region_size = aligned_region_size < rounded_mem_size + ? aligned_region_size + 1 + : rounded_mem_size + 1; + + if (aligned_region_size != specified_mem_size) + pr_warn("Truncating memory from 0x%.8lx to 0x%.8lx (MPU region constraints)", + (unsigned long)specified_mem_size, + (unsigned long)aligned_region_size); + + meminfo.bank[0].size = aligned_region_size; + pr_debug("MPU Region from 0x%.8lx size 0x%.8lx (end 0x%.8lx))\n", + (unsigned long)phys_offset, + (unsigned long)aligned_region_size, + (unsigned long)bank_phys_end(&bank[0])); + +} + +static int mpu_present(void) +{ + return ((read_cpuid_ext(CPUID_EXT_MMFR0) & MMFR0_PMSA) == MMFR0_PMSAv7); +} + +static int mpu_max_regions(void) +{ + /* + * We don't support a different number of I/D side regions so if we + * have separate instruction and data memory maps then return + * whichever side has a smaller number of supported regions. + */ + u32 dregions, iregions, mpuir; + mpuir = read_cpuid(CPUID_MPUIR); + + dregions = iregions = (mpuir & MPUIR_DREGION_SZMASK) >> MPUIR_DREGION; + + /* Check for separate d-side and i-side memory maps */ + if (mpuir & MPUIR_nU) + iregions = (mpuir & MPUIR_IREGION_SZMASK) >> MPUIR_IREGION; + + /* Use the smallest of the two maxima */ + return min(dregions, iregions); +} + +static int mpu_iside_independent(void) +{ + /* MPUIR.nU specifies whether there is *not* a unified memory map */ + return read_cpuid(CPUID_MPUIR) & MPUIR_nU; +} + +static int mpu_min_region_order(void) +{ + u32 drbar_result, irbar_result; + /* We've kept a region free for this probing */ + rgnr_write(MPU_PROBE_REGION); + isb(); + /* + * As per ARM ARM, write 0xFFFFFFFC to DRBAR to find the minimum + * region order + */ + drbar_write(0xFFFFFFFC); + drbar_result = irbar_result = drbar_read(); + drbar_write(0x0); + /* If the MPU is non-unified, we use the larger of the two minima*/ + if (mpu_iside_independent()) { + irbar_write(0xFFFFFFFC); + irbar_result = irbar_read(); + irbar_write(0x0); + } + isb(); /* Ensure that MPU region operations have completed */ + /* Return whichever result is larger */ + return __ffs(max(drbar_result, irbar_result)); +} + +static int mpu_setup_region(unsigned int number, phys_addr_t start, + unsigned int size_order, unsigned int properties) +{ + u32 size_data; + + /* We kept a region free for probing resolution of MPU regions*/ + if (number > mpu_max_regions() || number == MPU_PROBE_REGION) + return -ENOENT; + + if (size_order > 32) + return -ENOMEM; + + if (size_order < mpu_min_region_order()) + return -ENOMEM; + + /* Writing N to bits 5:1 (RSR_SZ) specifies region size 2^N+1 */ + size_data = ((size_order - 1) << MPU_RSR_SZ) | 1 << MPU_RSR_EN; + + dsb(); /* Ensure all previous data accesses occur with old mappings */ + rgnr_write(number); + isb(); + drbar_write(start); + dracr_write(properties); + isb(); /* Propagate properties before enabling region */ + drsr_write(size_data); + + /* Check for independent I-side registers */ + if (mpu_iside_independent()) { + irbar_write(start); + iracr_write(properties); + isb(); + irsr_write(size_data); + } + isb(); + + /* Store region info (we treat i/d side the same, so only store d) */ + mpu_rgn_info.rgns[number].dracr = properties; + mpu_rgn_info.rgns[number].drbar = start; + mpu_rgn_info.rgns[number].drsr = size_data; + return 0; +} + +/* +* Set up default MPU regions, doing nothing if there is no MPU +*/ +void __init mpu_setup(void) +{ + int region_err; + if (!mpu_present()) + return; + + region_err = mpu_setup_region(MPU_RAM_REGION, PHYS_OFFSET, + ilog2(meminfo.bank[0].size), + MPU_AP_PL1RW_PL0RW | MPU_RGN_NORMAL); + if (region_err) { + panic("MPU region initialization failure! %d", region_err); + } else { + pr_info("Using ARMv7 PMSA Compliant MPU. " + "Region independence: %s, Max regions: %d\n", + mpu_iside_independent() ? "Yes" : "No", + mpu_max_regions()); + } +} +#endif /* CONFIG_ARM_MPU */ + void __init arm_mm_memblock_reserve(void) { #ifndef CONFIG_CPU_V7M |