[platform][qemu-riscv] add virtio to bring it up to par with arm virt machine

platform/qemu-virt-riscv/include/platform/virt.h

@@ -21,6 +21,8 @@
 #define UART0_BASE  0x10000000
 #define VIRTIO_BASE 0x10001000
 #define DRAM_BASE   0x80000000
+#define NUM_VIRTIO_TRANSPORTS 8
+#define VIRTIO_STRIDE 0x1000
 
 #if RISCV_XMODE_OFFSET == RISCV_MACH_OFFSET
 #define PLIC_HART_IDX(hart)    (2 * (hart))

platform/qemu-virt-riscv/platform.c

@@ -16,6 +16,11 @@
 #include <platform/virt.h>
 #include <sys/types.h>
 #include <libfdt.h>
+#include <dev/virtio.h>
+#include <dev/virtio/net.h>
+#if WITH_LIB_MINIP
+#include <lib/minip.h>
+#endif
 
 #include "platform_p.h"
 
@@ -89,6 +94,35 @@ void platform_early_init(void) {
 void platform_init(void) {
     plic_init();
     uart_init();
+
+    /* detect any virtio devices */
+    uint virtio_irqs[NUM_VIRTIO_TRANSPORTS];
+    for (int i = 0; i < NUM_VIRTIO_TRANSPORTS; i++) {
+        virtio_irqs[i] = IRQ_VIRTIO_BASE + i;
+    }
+
+    virtio_mmio_detect((void *)VIRTIO_BASE, NUM_VIRTIO_TRANSPORTS, virtio_irqs, VIRTIO_STRIDE);
+
+#if WITH_LIB_MINIP
+    if (virtio_net_found() > 0) {
+        uint8_t mac_addr[6];
+
+        virtio_net_get_mac_addr(mac_addr);
+
+        TRACEF("found virtio networking interface\n");
+
+        /* start minip */
+        minip_set_macaddr(mac_addr);
+
+        __UNUSED uint32_t ip_addr = IPV4(192, 168, 0, 99);
+        __UNUSED uint32_t ip_mask = IPV4(255, 255, 255, 0);
+        __UNUSED uint32_t ip_gateway = IPV4_NONE;
+
+        //minip_init(virtio_net_send_minip_pkt, NULL, ip_addr, ip_mask, ip_gateway);
+        minip_init_dhcp(virtio_net_send_minip_pkt, NULL);
+
+        virtio_net_start();
+    }
+#endif
 }
 
-

platform/qemu-virt-riscv/rules.mk

@@ -10,6 +10,9 @@ SMP_MAX_CPUS ?= 8
 
 MODULE_DEPS += lib/cbuf
 MODULE_DEPS += lib/fdt
+MODULE_DEPS += dev/virtio/block
+MODULE_DEPS += dev/virtio/gpu
+MODULE_DEPS += dev/virtio/net
 
 MODULE_SRCS += $(LOCAL_DIR)/platform.c
 MODULE_SRCS += $(LOCAL_DIR)/plic.c
@@ -33,4 +36,11 @@ GLOBAL_DEFINES += ARCH_RISCV_MTIME_RATE=10000000
 # we're going to read the default memory map from a FDT
 GLOBAL_DEFINES += NOVM_DEFAULT_ARENA=0
 
+# we can revert to a poll based uart spin routine
+GLOBAL_DEFINES += PLATFORM_SUPPORTS_PANIC_SHELL=1
+
+# do not need to implement any cache ops
+# (for now, since there are no hw accellerated qemu machines)
+GLOBAL_DEFINES += RISCV_NO_CACHE_OPS=1
+
 include make/module.mk

platform/qemu-virt-riscv/uart.c

@@ -79,3 +79,12 @@ int platform_dgetc(char *c, bool wait) {
     return ret;
 }
 
+/* panic-time getc/putc */
+int platform_pgetc(char *c, bool wait) {
+    if (uart_read_8(5) & (1<<0)) {
+        *c = uart_read_8(0);
+        return 0;
+    }
+    return -1;
+}
+