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IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /*! * @file mmu.c * @brief System memory arangement. */ #include "cortex_a.h" #include "mmu.h" #include "arm_cp_registers.h" //////////////////////////////////////////////////////////////////////////////// // Definitions //////////////////////////////////////////////////////////////////////////////// //! @brief Size in bytes of the first-level page table. #define MMU_L1_PAGE_TABLE_SIZE (16 * 1024) //! @brief First-level 1MB section descriptor entry. typedef union mmu_l1_section { uint32_t u; struct { uint32_t id:2; //!< ID uint32_t b:1; //!< Bufferable uint32_t c:1; //!< Cacheable uint32_t xn:1; //!< Execute-not uint32_t domain:4; //!< Domain uint32_t _impl_defined:1; //!< Implementation defined, should be zero. uint32_t ap1_0:2; //!< Access permissions AP[1:0] uint32_t tex:3; //!< TEX remap uint32_t ap2:1; //!< Access permissions AP[2] uint32_t s:1; //!< Shareable uint32_t ng:1; //!< Not-global uint32_t _zero:1; //!< Should be zero. uint32_t ns:1; //!< Non-secure uint32_t address:12; //!< Physical base address }; } mmu_l1_section_t; enum { kMMU_L1_Section_ID = 2, //!< ID value for a 1MB section first-level entry. kMMU_L1_Section_Address_Shift = 20 //!< Bit offset of the physical base address field. }; //////////////////////////////////////////////////////////////////////////////// // Externs //////////////////////////////////////////////////////////////////////////////// extern char __l1_page_table_start; //////////////////////////////////////////////////////////////////////////////// // Code //////////////////////////////////////////////////////////////////////////////// void mmu_enable() { // invalidate all tlb arm_unified_tlb_invalidate(); // read SCTLR uint32_t sctlr; _ARM_MRC(15, 0, sctlr, 1, 0, 0); // set MMU enable bit sctlr |= BM_SCTLR_M; // write modified SCTLR _ARM_MCR(15, 0, sctlr, 1, 0, 0); } void mmu_disable() { // read current SCTLR uint32_t sctlr; _ARM_MRC(15, 0, sctlr, 1, 0, 0); // clear MMU enable bit sctlr &=~ BM_SCTLR_M; // write modified SCTLR _ARM_MCR(15, 0, sctlr, 1, 0, 0); } void mmu_init() { // Get the L1 page table base address. uint32_t * table = (uint32_t *)&__l1_page_table_start; uint32_t share_attr = kShareable; // write table address to TTBR0 _ARM_MCR(15, 0, table, 2, 0, 0); // set Client mode for all Domains uint32_t dacr = 0x55555555; _ARM_MCR(15, 0, dacr, 3, 0, 0); // MCR p15, 0, , c3, c0, 0 ; Write DACR // Clear the L1 table. bzero(table, MMU_L1_PAGE_TABLE_SIZE); // Create default mappings. mmu_map_l1_range(0x00000000, 0x00000000, 0x00900000, kStronglyOrdered, kShareable, kRWAccess); // ROM and peripherals mmu_map_l1_range(0x00900000, 0x00900000, 0x00100000, kStronglyOrdered, kShareable, kRWAccess); // OCRAM mmu_map_l1_range(0x00a00000, 0x00a00000, 0x0f600000, kStronglyOrdered, kShareable, kRWAccess); // More peripherals // Check whether SMP is enabled. If it is not, then we don't want to make SDRAM shareable. uint32_t actlr = 0x0; _ARM_MRC(15, 0, actlr, 1, 0, 1); if (actlr & BM_ACTLR_SMP) { share_attr = kShareable; } else { share_attr = kNonshareable; } #if defined(CHIP_MX6DQ) || defined(CHIP_MX6SDL) mmu_map_l1_range(0x10000000, 0x10000000, 0x80000000, kOuterInner_WB_WA, share_attr, kRWAccess); // 2GB DDR #elif defined(CHIP_MX6SL) || defined(CHIP_MX6UL) mmu_map_l1_range(0x80000000, 0x80000000, 0x40000000, kOuterInner_WB_WA, share_attr, kRWAccess); // 1GB DDR #else #error Unknown chip type! #endif } void mmu_map_l1_range(uint32_t pa, uint32_t va, uint32_t length, mmu_memory_type_t memoryType, mmu_shareability_t isShareable, mmu_access_t access) { register mmu_l1_section_t entry; entry.u = 0; // Set constant attributes. entry.id = kMMU_L1_Section_ID; entry.xn = 0; // Allow execution entry.domain = 0; // Domain 0 entry.ng = 0; // Global entry.ns = 0; // Secure // Set attributes based on the selected memory type. switch (memoryType) { case kStronglyOrdered: entry.c = 0; entry.b = 0; entry.tex = 0; entry.s = 1; // Ignored break; case kDevice: if (isShareable) { entry.c = 0; entry.b = 1; entry.tex = 0; entry.s = 1; // Ignored } else { entry.c = 0; entry.b = 0; entry.tex = 2; entry.s = 0; // Ignored } break; case kOuterInner_WB_WA: entry.c = 1; entry.b = 1; entry.tex = 1; entry.s = isShareable; break; case kOuterInner_WT: entry.c = 1; entry.b = 0; entry.tex = 0; entry.s = isShareable; break; case kNoncacheable: entry.c = 0; entry.b = 0; entry.tex = 1; entry.s = isShareable; break; } // Set attributes from specified access mode. switch (access) { case kNoAccess: entry.ap2 = 0; entry.ap1_0 = 0; break; case kROAccess: entry.ap2 = 1; entry.ap1_0 = 3; break; case kRWAccess: entry.ap2 = 0; entry.ap1_0 = 3; break; } // Get the L1 page table base address. uint32_t * table = (uint32_t *)&__l1_page_table_start; // Convert addresses to 12-bit bases. uint32_t vbase = va >> kMMU_L1_Section_Address_Shift; uint32_t pbase = pa >> kMMU_L1_Section_Address_Shift; uint32_t entries = length >> kMMU_L1_Section_Address_Shift; // Fill in L1 page table entries. for (; entries > 0; ++pbase, ++vbase, --entries) { entry.address = pbase; table[vbase] = entry.u; } // Invalidate TLB arm_unified_tlb_invalidate(); } bool mmu_virtual_to_physical(uint32_t virtualAddress, uint32_t * physicalAddress) { uint32_t pa = 0; // VA to PA translation with privileged read permission check _ARM_MCR(15, 0, virtualAddress & 0xfffffc00, 7, 8, 0); // Read PA register _ARM_MRC(15, 0, pa, 7, 4, 0); // First bit of returned value is Result of conversion (0 is successful translation) if (pa & 1) { // We can try write permission also // VA to PA translation with privileged write permission check _ARM_MCR(15, 0, virtualAddress & 0xfffffc00, 7, 8, 1); // Read PA register _ARM_MRC(15, 0, pa, 7, 4, 0); // First bit of returned value is Result of conversion (0 is successful translation) if (pa & 1) { return false; } } if (physicalAddress) { // complete address returning base + offset pa = (pa & 0xfffff000) | (virtualAddress & 0x00000fff); *physicalAddress = pa; } return true; } //////////////////////////////////////////////////////////////////////////////// // EOF ////////////////////////////////////////////////////////////////////////////////