x86: qemu: Add graphics support

It turns out that QEMU x86 emulated graphic card has a built-in
option ROM which can be run perfectly with native mode by U-Boot.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/qemu/pci.c

@@ -6,6 +6,7 @@
 
 #include <common.h>
 #include <pci.h>
+#include <pci_rom.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -45,5 +46,26 @@ void board_pci_setup_hose(struct pci_controller *hose)
 
 int board_pci_post_scan(struct pci_controller *hose)
 {
-	return 0;
+	int ret = 0;
+	ulong start;
+	pci_dev_t bdf;
+	struct pci_device_id graphic_card[] = { { 0x1234, 0x1111 } };
+
+	/*
+	 * QEMU emulated graphic card shows in the PCI configuration space with
+	 * PCI vendor id and device id as an artificial pair 0x1234:0x1111.
+	 * It is on PCI bus 0, function 0, but device number is not consistent
+	 * for the two x86 targets it supports. For i440FX and PIIX chipset
+	 * board, it shows as device 2, while for Q35 and ICH9 chipset board,
+	 * it shows as device 1. Here we locate its bdf at run-time based on
+	 * its vendor id and device id pair so we can support both boards.
+	 */
+	bdf = pci_find_devices(graphic_card, 0);
+	if (bdf != -1) {
+		start = get_timer(0);
+		ret = pci_run_vga_bios(bdf, NULL, PCI_ROM_USE_NATIVE);
+		debug("BIOS ran in %lums\n", get_timer(start));
+	}
+
+	return ret;
 }

configs/qemu-x86_defconfig

@@ -5,3 +5,6 @@ CONFIG_CMD_NET=y
 CONFIG_OF_CONTROL=y
 CONFIG_OF_SEPARATE=y
 CONFIG_DEFAULT_DEVICE_TREE="qemu-x86"
+CONFIG_VIDEO_VESA=y
+CONFIG_FRAMEBUFFER_SET_VESA_MODE=y
+CONFIG_FRAMEBUFFER_VESA_MODE_111=y

doc/README.x86

@@ -218,7 +218,8 @@ works correctly for link though.
 Test with QEMU
 --------------
 QEMU is a fancy emulator that can enable us to test U-Boot without access to
-a real x86 board. To launch QEMU with u-boot.rom, call QEMU as follows:
+a real x86 board. Please make sure your QEMU version is 2.3.0 or above test
+U-Boot. To launch QEMU with u-boot.rom, call QEMU as follows:
 
 $ qemu-system-i386 -nographic -bios path/to/u-boot.rom
 
@@ -239,6 +240,10 @@ supports 3 GiB maximum system memory and reserves the last 1 GiB address space
 for PCI device memory-mapped I/O and other stuff, so the maximum value of '-m'
 would be 3072.
 
+QEMU emulates a graphic card which U-Boot supports. Removing '-nographic' will
+show QEMU's VGA console window. Note this will disable QEMU's serial output.
+If you want to check both consoles, use '-serial stdio'.
+
 CPU Microcode
 -------------
 Modern CPUs usually require a special bit stream called microcode [6] to be

include/configs/qemu-x86.h

@@ -32,9 +32,9 @@
 #define CONFIG_PCI_PNP
 #define CONFIG_E1000
 
-#define CONFIG_STD_DEVICES_SETTINGS	"stdin=serial\0" \
+#define CONFIG_STD_DEVICES_SETTINGS	"stdin=serial,vga\0" \
-					"stdout=serial\0" \
+					"stdout=serial,vga\0" \
-					"stderr=serial\0"
+					"stderr=serial,vga\0"
 
 #define CONFIG_SCSI_DEV_LIST		\
 	{PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371SB_1}
@@ -48,8 +48,4 @@
 #undef CONFIG_ENV_IS_IN_SPI_FLASH
 #define CONFIG_ENV_IS_NOWHERE
 
-/* Video is not supported */
-#undef CONFIG_VIDEO
-#undef CONFIG_CFB_CONSOLE
-
 #endif	/* __CONFIG_H */