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Trying to setup the mmu

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This commit is contained in:
Scott Shawcroft 2021-09-22 15:19:02 -07:00
parent 2499c9382d
commit 829f92d00f
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GPG Key ID: 0DFD512649C052DA
6 changed files with 132 additions and 17 deletions
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24
hw/bsp/raspberrypi4/family.c
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@ -28,6 +28,7 @@
#include "board.h"
#include "io.h"
#include "mmu.h"
//--------------------------------------------------------------------+
// Forward USB interrupt events to TinyUSB IRQ Handler
@ -55,6 +56,7 @@ void board_init(void)
gpio_initOutputPinWithPullNone(18);
gpio_setPinOutputBool(18, true);
gpio_initOutputPinWithPullNone(42);
setup_mmu_flat_map();
// gpio_initOutputPinWithPullNone(23);
// gpio_initOutputPinWithPullNone(24);
// gpio_initOutputPinWithPullNone(25);
@ -83,17 +85,17 @@ void board_init(void)
// gpio_setPinOutputBool(25, true);
print();
// gpio_setPinOutputBool(25, false);
while (true) {
// for (size_t i = 0; i < 5; i++) {
for (size_t j = 0; j < 10000000000; j++) {
__asm__("nop");
}
gpio_setPinOutputBool(42, true);
for (size_t j = 0; j < 10000000000; j++) {
__asm__("nop");
}
gpio_setPinOutputBool(42, false);
}
// while (true) {
// // for (size_t i = 0; i < 5; i++) {
// for (size_t j = 0; j < 10000000000; j++) {
// __asm__("nop");
// }
// gpio_setPinOutputBool(42, true);
// for (size_t j = 0; j < 10000000000; j++) {
// __asm__("nop");
// }
// gpio_setPinOutputBool(42, false);
// }
// while (1) uart_update();
}

3
hw/bsp/raspberrypi4/family.mk
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@ -18,8 +18,9 @@ CFLAGS += \
SRC_C += \
src/portable/broadcom/synopsys/dcd_synopsys.c \
$(MCU_DIR)/interrupts.c \
$(MCU_DIR)/io.c \
$(MCU_DIR)/interrupts.c
$(MCU_DIR)/mmu.c
CROSS_COMPILE = aarch64-none-elf-

4
hw/mcu/broadcom/bcm2711/boot.s
View File

@ -19,7 +19,7 @@ _start:
adr x0, vectors // load VBAR_EL1 with virtual
// msr vbar_el3, x0 // vector table address
msr vbar_el1, x0 // vector table address
// msr vbar_el2, x0 // vector table address
msr vbar_el2, x0 // vector table address
isb
// Clean the BSS section
@ -45,6 +45,8 @@ irq_entry
mov x0, #\type
mrs x1, esr_el1
mrs x2, elr_el1
mrs x3, esr_el2
mrs x4, elr_el2
b err_hang
.endm

16
hw/mcu/broadcom/bcm2711/link.ld
View File

@ -1,12 +1,20 @@
SECTIONS
{
. = 0x80000; /* Kernel load address for AArch64 */
.text : { KEEP(*(.text.boot)) *(.text .text.* .gnu.linkonce.t*) }
.rodata : { *(.rodata .rodata.* .gnu.linkonce.r*) }
.text : {
KEEP(*(.text.boot))
*(.text .text.* .gnu.linkonce.t*)
}
.rodata : {
. = ALIGN(4096);
*(.rodata .rodata.* .gnu.linkonce.r*)
}
PROVIDE(_data = .);
.data : { *(.data .data.* .gnu.linkonce.d*) }
.data : {
. = ALIGN(4096);
*(.data .data.* .gnu.linkonce.d*)
}
.bss (NOLOAD) : {
. = ALIGN(16);
__bss_start = .;
*(.bss .bss.*)
*(COMMON)

58
hw/mcu/broadcom/bcm2711/mmu.c Normal file
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@ -0,0 +1,58 @@
#include <stdbool.h>
#include <stdint.h>
#include "mmu.h"
// Each entry is a gig.
volatile uint64_t level_1_table[32] __attribute__((aligned(4096)));
// Third gig has peripherals
uint64_t level_2_0x0_c000_0000_to_0x1_0000_0000[512] __attribute__((aligned(4096)));
void setup_mmu_flat_map(void) {
// Set the first gig to regular access.
level_1_table[0] = 0x0000000000000000 |
MM_DESCRIPTOR_MAIR_INDEX(MT_NORMAL_NC) |
MM_DESCRIPTOR_BLOCK |
MM_DESCRIPTOR_VALID;
level_1_table[2] = ((uint64_t) level_2_0x0_c000_0000_to_0x1_0000_0000) |
MM_DESCRIPTOR_TABLE |
MM_DESCRIPTOR_VALID;
// Set peripherals to register access.
for (uint64_t i = 480; i < 512; i++) {
level_2_0x0_c000_0000_to_0x1_0000_0000[i] = (0x00000000c0000000 + (i << 21)) |
MM_DESCRIPTOR_EXECUTE_NEVER |
MM_DESCRIPTOR_MAIR_INDEX(MT_DEVICE_nGnRnE) |
MM_DESCRIPTOR_BLOCK |
MM_DESCRIPTOR_VALID;
}
uint64_t mair = MAIR_VALUE;
uint64_t tcr = TCR_VALUE;
uint64_t ttbr0 = ((uint64_t) level_1_table) | MM_TTBR_CNP;
uint64_t sctlr = 0;
__asm__ volatile (
// Set MAIR
"MSR MAIR_EL2, %[mair]\n\t"
// Set TTBR0
"MSR TTBR0_EL2, %[ttbr0]\n\t"
// Set TCR
"MSR TCR_EL2, %[tcr]\n\t"
// The ISB forces these changes to be seen before the MMU is enabled.
"ISB\n\t"
// Read System Control Register configuration data
"MRS %[sctlr], SCTLR_EL2\n\t"
// Write System Control Register configuration data
"ORR %[sctlr], %[sctlr], #1\n\t"
// Set [M] bit and enable the MMU.
"MSR SCTLR_EL2, %[sctlr]\n\t"
// The ISB forces these changes to be seen by the next instruction
"ISB"
: /* No outputs. */
: [mair] "r" (mair),
[tcr] "r" (tcr),
[ttbr0] "r" (ttbr0),
[sctlr] "r" (sctlr)
);
while (true) {}
}

44
hw/mcu/broadcom/bcm2711/mmu.h Normal file
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@ -0,0 +1,44 @@
#pragma once
// From: https://github.com/s-matyukevich/raspberry-pi-os/blob/master/docs/lesson06/rpi-os.md
/*
* Memory region attributes:
*
* n = AttrIndx[2:0]
* n MAIR
* DEVICE_nGnRnE 000 00000000
* NORMAL_NC 001 01000100
*/
#define MT_DEVICE_nGnRnE 0x0
#define MT_NORMAL_NC 0x1
#define MT_DEVICE_nGnRnE_FLAGS 0x00
#define MT_NORMAL_NC_FLAGS 0x44
#define MAIR_VALUE (MT_DEVICE_nGnRnE_FLAGS << (8 * MT_DEVICE_nGnRnE)) | (MT_NORMAL_NC_FLAGS << (8 * MT_NORMAL_NC))
#define TCR_T0SZ (64 - 35)
#define TCR_PS (0x01 << 16) // 36-bit physical address
#define TCR_TG0_4K (0 << 14)
#define TCR_SH0_OUTER_SHAREABLE (0x2 << 12)
#define TCR_VALUE (TCR_T0SZ | TCR_PS | TCR_TG0_4K | TCR_SH0_OUTER_SHAREABLE)
#define ENTRY_TYPE_TABLE_DESCRIPTOR 0x11
#define ENTRY_TYPE_BLOCK_ENTRY 0x01
#define ENTRY_TYPE_TABLE_ENTRY 0x11
#define ENTRY_TYPE_INVALID 0x00
#define MM_DESCRIPTOR_VALID (0x1)
#define MM_DESCRIPTOR_BLOCK (0x0 << 1)
#define MM_DESCRIPTOR_TABLE (0x1 << 1)
// Block attributes
#define MM_DESCRIPTOR_EXECUTE_NEVER (0x1ull << 54)
#define MM_DESCRIPTOR_CONTIGUOUS (0x1ull << 52)
#define MM_DESCRIPTOR_MAIR_INDEX(index) (index << 2)
#define MM_TTBR_CNP (0x1)
void setup_mmu_flat_map(void);