Record networking and DMA development progress

Add the current OS source tree, build scripts, system image layout, and development notes covering DMA page allocation, e1000 bring-up, net API dispatch, and DHCP work in progress.

CODE/UTSM/include/utsm/block.h

@@ -0,0 +1,29 @@
+#ifndef UTSM_BLOCK_H
+#define UTSM_BLOCK_H
+
+#include <utsm/types.h>
+
+#define DKM_BLOCK_MAX_DEVICES 8u
+
+typedef int (*dkm_block_read_fn)(void *ctx, u64 lba, u32 count, void *buffer);
+
+typedef struct dkm_block_device_desc {
+    const char *name;
+    u64 sector_size;
+    u64 sector_count;
+    void *ctx;
+    dkm_block_read_fn read;
+} dkm_block_device_desc;
+
+typedef struct dkm_block_api {
+    int (*register_device)(const dkm_block_device_desc *desc);
+    u32 (*device_count)(void);
+    int (*read)(u32 index, u64 lba, u32 count, void *buffer);
+    u64 (*sector_size)(u32 index);
+    const char *(*device_name)(u32 index);
+} dkm_block_api;
+
+void block_init(void);
+const dkm_block_api *block_get_api(void);
+
+#endif