Implement V86 monitor and VESA mode detection.

1 files changed, 84 insertions, 0 deletions

diff --git a/src/kernel/dev/vesa.c b/src/kernel/dev/vesa.c
new file mode 100644
index 0000000..6b23a34
--- /dev/null
+++ b/src/kernel/dev/vesa.c
@@ -0,0 +1,84 @@
+#include <string.h>
+
+#include <dev/vesa.h>
+#include <dev/v86.h>
+
+//  ---- VESA data structures
+
+typedef struct {
+	char vbe_signature[4];				// == "VESA"
+	uint16_t vbe_version;
+	v86_farptr_t oem_string_ptr;
+	uint8_t capabilities[4];
+	v86_farptr_t video_mode_ptr;
+	uint16_t total_memory;				// as # of 64KB blocks
+} __attribute__((packed)) vbe_info_block_t;
+
+typedef struct {
+	uint16_t attributes;
+	uint8_t winA, winB;
+	uint16_t granularity;
+	uint16_t winsize;
+	uint16_t segmentA, segmentB;
+	v86_farptr_t real_fct_ptr;
+	uint16_t pitch; // bytes per scanline
+
+	uint16_t Xres, Yres;
+	uint8_t Wchar, Ychar, planes, bpp, banks;
+	uint8_t memory_model, bank_size, image_pages;
+	uint8_t reserved0;
+
+	uint8_t red_mask, red_position;
+	uint8_t green_mask, green_position;
+	uint8_t blue_mask, blue_position;
+	uint8_t rsv_mask, rsv_position;
+	uint8_t directcolor_attributes;
+
+	uint32_t physbase;		// the offset of the framebuffer in physical memory!
+	uint32_t reserved1;
+	uint16_t reserved2;
+} __attribute__((packed)) vbe_mode_info_block_t;
+
+//  ---- VESA code
+
+void vesa_detect(fs_t *iofs) {
+	if (!v86_begin_session()) return;
+	
+	vbe_info_block_t *i = (vbe_info_block_t*)v86_alloc(512);
+	memset(i, 0, 512);
+	strncpy(i->vbe_signature, "VBE2", 4);
+
+	v86_regs.ax = 0x4F00;
+	v86_regs.es = V86_SEG_OF_LIN(i);
+	v86_regs.di = V86_OFF_OF_LIN(i);
+
+	if (v86_bios_int(0x10)) {
+		if (v86_regs.ax == 0x004F) {
+			dbg_printf("Detected VESA (sig %s, ver 0x%x, oem %s) with %d kb ram.\n",
+				i->vbe_signature, i->vbe_version, v86_lin_of_fp(i->oem_string_ptr), 64 * i->total_memory);
+
+			vbe_mode_info_block_t *mi = (vbe_mode_info_block_t*)v86_alloc(256);
+
+			uint16_t *modes = (uint16_t*)v86_lin_of_fp(i->video_mode_ptr);
+			for (int n = 0; modes[n] != 0xFFFF; n++) {
+				v86_regs.ax = 0x4F01;
+				v86_regs.cx = modes[n];
+				v86_regs.es = V86_SEG_OF_LIN(mi);
+				v86_regs.di = V86_OFF_OF_LIN(mi);
+				if (v86_bios_int(0x10) && v86_regs.ax == 0x004F) {
+					dbg_printf("Mode 0x%x : %dx%dx%d at 0x%p\n", modes[n], mi->Xres, mi->Yres, mi->bpp, mi->physbase);
+				} else {
+					dbg_printf("Mode 0x%x : could not get info\n", modes[n]);
+				}
+			}
+		} else {
+			dbg_printf("Error in BIOS int 0x10/0x4F00.\n");
+		}
+	} else {
+		dbg_printf("Could not call BIOS int 0x10.\n");
+	}
+
+	v86_end_session();
+}
+
+/* vim: set ts=4 sw=4 tw=0 noet :*/