use core::mem::uninitialized; use bit_field::BitField; use super::{regs::*, asm}; use crate::regs::RegisterW; #[derive(Copy, Clone)] #[repr(u8)] pub enum AccessDomain { NoAccess = 0b00, Client = 0b01, _Reserved = 0b10, Manager = 0b11, } const ACCESS_DOMAINS_SIZE: usize = 16; pub struct AccessDomains([AccessDomain; ACCESS_DOMAINS_SIZE]); impl AccessDomains { pub fn all_manager() -> Self { AccessDomains([AccessDomain::Manager; ACCESS_DOMAINS_SIZE]) } } impl Into for AccessDomains { fn into(self) -> u32 { let mut result = 0; for (i, domain) in self.0.iter().enumerate() { result |= (*domain as u32) << (2 * i); } result } } #[derive(Copy, Clone)] #[repr(u8)] pub enum AccessPermissions { PermissionFault = 0, PrivilegedOnly, NoUserWrite, FullAccess, _Reserved1, PrivilegedReadOnly, ReadOnly, _Reserved2 } impl AccessPermissions { fn ap(&self) -> u8 { (*self as u8) & 0b11 } fn apx(&self) -> bool { (*self as u8) > (AccessPermissions::FullAccess as u8) } } pub struct L1Section { pub global: bool, pub shareable: bool, pub access: AccessPermissions, /// Type EXtension pub tex: u8, pub domain: u8, pub exec: bool, pub cacheable: bool, pub bufferable: bool, } #[repr(C)] #[derive(Clone, Copy)] pub struct L1Entry(u32); impl L1Entry { #[inline(always)] pub fn section(phys_base: u32, section: L1Section) -> Self { /// Must be aligned to 1 MB assert!(phys_base & 0x000f_ffff == 0); let mut entry = L1Entry(phys_base); entry.0.set_bits(0..=1, 0b10); entry.0.set_bit(2, section.bufferable); entry.0.set_bit(3, section.cacheable); entry.0.set_bit(4, !section.exec); assert!(section.domain < 16); entry.0.set_bits(5..=8, section.domain.into()); entry.0.set_bits(10..=11, section.access.ap().into()); assert!(section.tex < 8); entry.0.set_bits(12..=14, section.tex.into()); entry.0.set_bit(15, section.access.apx()); entry.0.set_bit(16, section.shareable); entry.0.set_bit(17, !section.global); entry } } const L1TABLE_SIZE: usize = 4096; #[repr(C, align(16384))] pub struct L1Table { table: [L1Entry; L1TABLE_SIZE] } impl L1Table { pub fn flat_layout() -> Self { let mut result = L1Table { table: unsafe { uninitialized() } }; /* 0x00000000 - 0x00100000 (cacheable) */ result.direct_mapped_section(0, L1Section { global: true, shareable: true, access: AccessPermissions::FullAccess, tex: 0b101, domain: 0b1111, exec: true, cacheable: false, bufferable: true, }); /* (DDR cacheable) */ for ddr in 1..=0x1ff { result.direct_mapped_section(ddr, L1Section { global: true, shareable: true, access: AccessPermissions::FullAccess, tex: 0b101, domain: 0b1111, exec: true, cacheable: true, bufferable: true, }); } /* (unassigned/reserved). */ for undef in 0x1ff..=0x3ff { result.direct_mapped_section(undef, L1Section { global: false, shareable: false, access: AccessPermissions::PermissionFault, tex: 0, domain: 0, exec: false, cacheable: false, bufferable: false, }); } /* 0x40000000 - 0x7fffffff (FPGA slave0) */ for fpga_slave in 0x400..=0x7ff { result.direct_mapped_section(fpga_slave, L1Section { global: true, shareable: false, access: AccessPermissions::FullAccess, tex: 0, domain: 0, exec: false, cacheable: false, bufferable: false, }); } /* 0x80000000 - 0xbfffffff (FPGA slave1) */ for fpga_slave in 0x800..=0xbff { result.direct_mapped_section(fpga_slave, L1Section { global: true, shareable: false, access: AccessPermissions::FullAccess, tex: 0, domain: 0, exec: false, cacheable: false, bufferable: false, }); } /* 0xc0000000 - 0xdfffffff (unassigned/reserved). */ for undef in 0xc00..=0xdff { result.direct_mapped_section(undef, L1Section { global: false, shareable: false, access: AccessPermissions::PermissionFault, tex: 0, domain: 0, exec: false, cacheable: false, bufferable: false, }); } /* 0xe0000000 - 0xe02fffff (Memory mapped devices) * UART/USB/IIC/SPI/CAN/GEM/GPIO/QSPI/SD/NAND */ for mmapped_dev in 0xe00..=0xe02 { result.direct_mapped_section(mmapped_dev, L1Section { global: true, shareable: false, access: AccessPermissions::FullAccess, tex: 0, domain: 0, exec: true, cacheable: false, bufferable: true, }); } /* 0xe0300000 - 0xe0ffffff (unassigned/reserved). */ for undef in 0xe03..=0xe0f { result.direct_mapped_section(undef, L1Section { global: false, shareable: false, access: AccessPermissions::PermissionFault, tex: 0, domain: 0, exec: false, cacheable: false, bufferable: false, }); } /* 0xe1000000 - 0xe1ffffff (NAND) */ for nand in 0xe10..=0xe1f { result.direct_mapped_section(nand, L1Section { global: true, shareable: false, access: AccessPermissions::FullAccess, tex: 0, domain: 0, exec: true, cacheable: false, bufferable: true, }); } /* 0xe2000000 - 0xe3ffffff (NOR) */ for nor in 0xe20..=0xe3f { result.direct_mapped_section(nor, L1Section { global: true, shareable: false, access: AccessPermissions::FullAccess, tex: 0, domain: 0, exec: true, cacheable: false, bufferable: true, }); } /* 0xe4000000 - 0xe5ffffff (SRAM) */ for nor in 0xe40..=0xe5f { result.direct_mapped_section(nor, L1Section { global: true, shareable: false, access: AccessPermissions::FullAccess, tex: 0, domain: 0, exec: true, cacheable: true, bufferable: true, }); } /* 0xe6000000 - 0xf7ffffff (unassigned/reserved). */ for undef in 0xe60..=0xf7f { result.direct_mapped_section(undef, L1Section { global: false, shareable: false, access: AccessPermissions::PermissionFault, tex: 0, domain: 0, exec: false, cacheable: false, bufferable: false, }); } /* 0xf8000000 - 0xf8ffffff (AMBA APB Peripherals) */ for apb in 0xf80..=0xf8f { result.direct_mapped_section(apb, L1Section { global: true, shareable: false, access: AccessPermissions::FullAccess, tex: 0, domain: 0, exec: true, cacheable: false, bufferable: true, }); } /* 0xf9000000 - 0xfbffffff (unassigned/reserved). */ for undef in 0xf90..=0xfbf { result.direct_mapped_section(undef, L1Section { global: false, shareable: false, access: AccessPermissions::PermissionFault, tex: 0, domain: 0, exec: false, cacheable: false, bufferable: false, }); } /* 0xfc000000 - 0xfdffffff (Linear QSPI - XIP) */ for qspi in 0xfc0..=0xfdf { result.direct_mapped_section(qspi, L1Section { global: true, shareable: false, access: AccessPermissions::FullAccess, tex: 0, domain: 0, exec: true, cacheable: false, bufferable: true, }); } /* 0xfe000000 - 0xffefffff (unassigned/reserved). */ for undef in 0xfe0..=0xffe { result.direct_mapped_section(undef, L1Section { global: false, shareable: false, access: AccessPermissions::PermissionFault, tex: 0, domain: 0, exec: false, cacheable: false, bufferable: false, }); } /* 0xfff00000 - 0xffffffff (256K OCM when mapped to high address space) */ result.direct_mapped_section(0xfff, L1Section { global: true, shareable: false, access: AccessPermissions::FullAccess, tex: 0b100, domain: 0, exec: true, cacheable: true, bufferable: true, }); result } #[inline(always)] fn direct_mapped_section(&mut self, index: usize, section: L1Section) { assert!(index < L1TABLE_SIZE); let base = (index as u32) << 20; self.table[index] = L1Entry::section(base, section); } } pub fn with_mmu !>(l1table: &L1Table, mut f: F) -> ! { let domains = AccessDomains::all_manager(); DACR.write(domains.into()); let table_base = &l1table.table as *const _ as u32; assert!(table_base & 0x3fff == 0); TTBR0.write( TTBR0::zeroed() .irgn1(true) .s(true) // Outer Cacheable Write-Back, no allocate on write. .rgn(0b11) .irgn0(true) .table_base(table_base >> 14) ); // Enable I-Cache and D-Cache SCTLR.write( SCTLR::zeroed() .m(true) .a(false) .c(true) .i(true) .unaligned(true) ); // Synchronization barriers // Allows MMU to start asm::dsb(); // Flushes pre-fetch buffer asm::isb(); f(); // table must live until here drop(l1table.table); unreachable!(); }