commit 5ef80a822bca12cea4414cb9a62f700b0e5c36e2
parent c484f4fe3bd08fe03a55ae70f7091020018d6def
Author: Brian Swetland <swetland@frotz.net>
Date: Mon, 23 May 2022 01:39:48 -0700
boot: add netboot bootloader (out/boot.net.bin)
Diffstat:
2 files changed, 201 insertions(+), 0 deletions(-)
diff --git a/boot/netboot.c b/boot/netboot.c
@@ -0,0 +1,191 @@
+// Copyright 2022, Brian Swetland <swetland@frotz.net>
+// Licensed under the Apache License, Version 2.0
+
+#include <string.h>
+#include <stdio.h>
+
+#include <hw/riscv.h>
+#include <hw/context.h>
+#include <hw/intrinsics.h>
+#include <hw/debug.h>
+
+#include <hw/platform.h>
+#include <hw/litex.h>
+
+#include <net/ipv6.h>
+#include <netboot.h>
+
+#include "boot.h"
+
+// we expect the supervisor program to be in memory after the end of the bootloader
+#define SVC_ENTRY (DRAM_BASE + BOOTLOADER_SIZE)
+
+#define uart_rd(a) io_rd32(UART0_BASE + LX_UART_ ## a)
+#define uart_wr(a,v) io_wr32(UART0_BASE + LX_UART_ ## a, v)
+#define eth_rd(a) io_rd32(ETHMAC_BASE + LX_ETHMAC_ ## a)
+#define eth_wr(a,v) io_wr32(ETHMAC_BASE + LX_ETHMAC_ ## a, v)
+
+void halt_peripherals(void) {
+ eth_wr(WR_EV_ENABLE, 0);
+ eth_wr(RD_EV_ENABLE, 0);
+}
+
+const char *nodename = "device";
+
+void query_reply(void *replyto) {
+ netboot_msg_t *msg = replyto;
+ unsigned len = snprintf((void*)msg->db, NB_DATA_MAX, "name=%s", nodename);
+ msg->cmd = NB_CMD_STATUS;
+ msg->arg = NB_OK;
+ net_tx_udp_reply(replyto, msg, NB_MSG_MIN + len + 1, NB_PORT_CTRL);
+}
+
+void pkt_rx_udp(void *data, unsigned len, unsigned port, int mcast) {
+ netboot_msg_t* msg = data;
+ if ((len < NB_MSG_MIN) || (len > NB_MSG_MAX) || (msg->magic != NB_MAGIC)) {
+ return;
+ }
+
+ if (port == NB_PORT_QUERY) {
+ unsigned nlen = strlen(nodename);
+ // query port only replies to valid queries that match
+ if ((msg->cmd != NB_CMD_QUERY) ||
+ (len != (nlen + NB_MSG_MIN)) ||
+ (memcmp(msg->db, nodename, nlen))) {
+ return;
+ }
+ query_reply(data);
+ return;
+ }
+ if (port != NB_PORT_CTRL) {
+ return;
+ }
+
+ switch (msg->cmd) {
+ case NB_CMD_QUERY:
+ xputc('Q');
+ query_reply(data);
+ return;
+ case NB_CMD_WRITE:
+ xputc('.');
+ // TODO: apply range limits?
+ memcpy((void*) msg->arg, msg->db, len - NB_MSG_MIN);
+ msg->cmd = NB_CMD_STATUS;
+ msg->arg = NB_OK;
+ net_tx_udp_reply(data, msg, NB_MSG_MIN, NB_PORT_CTRL);
+ return;
+ case NB_CMD_EXEC: {
+ xputc('!');
+ uint32_t entry = msg->arg;
+ msg->cmd = NB_CMD_STATUS;
+ msg->arg = NB_OK;
+ net_tx_udp_reply(data, msg, NB_MSG_MIN, NB_PORT_CTRL);
+
+ csr_write(CSR_MSTATUS, PRIV_S << MSTATUS_MPP_SHIFT);
+ xprintf("\n\n[ execution starts at 0x%08x ]\n\n", entry);
+ exit_mode_m(0, 0, entry, 0);
+ return;
+ }
+ default:
+ xputc('E');
+ msg->cmd = NB_CMD_STATUS;
+ msg->arg = NB_ERR_BADCMD;
+ net_tx_udp_reply(data, msg, NB_MSG_MIN, NB_PORT_CTRL);
+ break;
+ }
+}
+
+uint8_t rxbuf[1536] = { 0, };
+
+void eth_rx(uint8_t *rxb, unsigned rxlen) {
+ if (rxlen > 1534) return;
+ memcpy(rxbuf + 2, rxb, rxlen);
+ net_rx_eth(rxbuf, rxlen + 2);
+}
+
+
+static unsigned txslot;
+
+void eth_tx(void *txb, unsigned txlen) {
+ if (txlen > 1534) return;
+
+ while (eth_rd(RD_READY) != 1) ;
+
+ memcpy((void*)(ETHMAC_SRAM_BASE + ETHMAC_SLOT_SIZE * (ETHMAC_RX_SLOTS + txslot)), txb, txlen);
+
+ eth_wr(RD_SLOT, txslot);
+ eth_wr(RD_LEN, txlen);
+ eth_wr(RD_START, 1);
+
+ txslot ^= 1;
+}
+
+void eth_init(void) {
+ eth_wr(WR_EV_ENABLE, 0);
+ eth_wr(RD_EV_ENABLE, 0);
+
+ eth_wr(WR_EV_PENDING, 1);
+ eth_wr(RD_EV_PENDING, 1);
+
+ txslot = 0;
+ eth_wr(RD_SLOT, txslot);
+
+ eth_wr(WR_EV_ENABLE, 1);
+ eth_wr(RD_EV_ENABLE, 1);
+}
+
+void eth_handle_rx(void) {
+ if (eth_rd(WR_EV_PENDING) & 1) {
+ uint32_t slot = eth_rd(WR_SLOT);
+ uint8_t *rxb = (void*) (ETHMAC_SRAM_BASE + ETHMAC_SLOT_SIZE * slot);
+ eth_rx(rxb, eth_rd(WR_LEN));
+ eth_wr(WR_EV_PENDING, 1);
+ }
+}
+
+void netboot(void) {
+ uint8_t mac[6] = { 0x42,0x42,0x10,0x20,0x30,0x40 };
+ net_init(mac);
+ eth_init();
+ for (;;) {
+ eth_handle_rx();
+ }
+}
+
+void mach_exception_handler(eframe_t *ef) {
+ xprintf("\n** MACHINE EXCEPTION **\n");
+ xprint_m_exception(ef);
+ xprintf("\nHALT\n");
+ for (;;) ;
+}
+
+// interrupts and exceptions to delegate to supervisor mode
+#define INT_LIST (INTb_SVC_SW|INTb_SVC_TIMER|INTb_SVC_EXTERN)
+//#define EXC_LIST (EXCb_ECALL_UMODE)
+#define EXC_LIST (0xFFFF)
+
+void start(uint32_t hartid, uint32_t fdt) {
+ xprintf("\n** Frobozz Magic (Network) Bootloader v0.2 **\n\n");
+
+ int qemu = (csr_read(CSR_MVENDORID) == 0);
+
+ // set mach exception vector and stack pointer
+ csr_write(CSR_MTVEC, ((uintptr_t) mach_exception_entry) );
+
+ // use the free ram below the supervisor entry as our exception stack
+ csr_write(CSR_MSCRATCH, SVC_ENTRY);
+
+ // QEMU currently emulates memory protection, which we must appease
+ if (qemu) {
+ // U/S allow access to all memory
+ csr_write(CSR_PMPCFG(0), PMP_CFG_A_TOR | PMP_CFG_X | PMP_CFG_W | PMP_CFG_R);
+ csr_write(CSR_PMPADDR(0), 0xFFFFFFFF);
+ }
+
+ // delegate interrupts and exceptions
+ csr_set(CSR_MIDELEG, INT_LIST);
+ csr_set(CSR_MEDELEG, EXC_LIST);
+
+ netboot();
+}
+
diff --git a/project/boot.net.app.mk b/project/boot.net.app.mk
@@ -0,0 +1,10 @@
+
+MOD_NAME := boot.net
+MOD_SRC := hw/src/start.S boot/entry.S boot/netboot.c
+MOD_SRC += net/ipv6.c
+MOD_SRC += hw/src/print-exception.c
+MOD_SRC += hw/src/debug-printf.c hw/src/debug-io.c
+MOD_LIB := c
+MOD_INC := tools net/inc
+MOD_LDSCRIPT := make/boot.ram.ld
+include make/app.mk
