[PATCH v5 23/46] pci: Allow the video BIOS to work in SPL with QEMU

[Simon Glass]

QEMU emulates two common machines (Q35 and i440fx) which use mapping to
determine whether RAM is present below 1MB. In order to copy the video
BIOS to c0000 we need to flip this mapping over to RAM. This does not
happen automatically until SPL has finished running.

Switch in RAM at these address so that the video BIOS can be loaded and
run.

Create a generic qemu.h header to avoid having to #ifdef the header in
pci_rom.c

Signed-off-by: Simon Glass <sjg at chromium.org>
---

Changes in v5:
- Use the existing QEMU code instead

 arch/x86/cpu/qemu/qemu.c |  5 +++--
 drivers/pci/pci_rom.c    |  5 +++++
 include/qemu.h           | 14 ++++++++++++++
 3 files changed, 22 insertions(+), 2 deletions(-)
 create mode 100644 include/qemu.h

diff --git a/arch/x86/cpu/qemu/qemu.c b/arch/x86/cpu/qemu/qemu.c
index 274978c023b6..a84d2aceda3c 100644
--- a/arch/x86/cpu/qemu/qemu.c
+++ b/arch/x86/cpu/qemu/qemu.c
@@ -7,6 +7,7 @@
 #include <cpu_func.h>
 #include <init.h>
 #include <pci.h>
+#include <qemu.h>
 #include <qfw.h>
 #include <dm/platdata.h>
 #include <asm/irq.h>
@@ -48,7 +49,7 @@ static void enable_pm_ich9(void)
 	pci_write_config32(ICH9_PM, PMBA, CONFIG_ACPI_PM1_BASE | 1);
 }
 
-static void qemu_chipset_init(void)
+void qemu_x86_chipset_init(void)
 {
 	u16 device, xbcs;
 	int pam, i;
@@ -119,7 +120,7 @@ int print_cpuinfo(void)
 
 int arch_early_init_r(void)
 {
-	qemu_chipset_init();
+	qemu_x86_chipset_init();
 
 	return 0;
 }
diff --git a/drivers/pci/pci_rom.c b/drivers/pci/pci_rom.c
index f0dfe6314907..447957fb23aa 100644
--- a/drivers/pci/pci_rom.c
+++ b/drivers/pci/pci_rom.c
@@ -34,6 +34,7 @@
 #include <malloc.h>
 #include <pci.h>
 #include <pci_rom.h>
+#include <qemu.h>
 #include <vesa.h>
 #include <video.h>
 #include <acpi/acpi_s3.h>
@@ -185,6 +186,10 @@ static int pci_rom_load(struct pci_rom_header *rom_header,
 		return -ENOMEM;
 	*allocedp = true;
 #endif
+	/* QEMU hacks */
+	if (IS_ENABLED(CONFIG_X86) && IS_ENABLED(CONFIG_QEMU))
+		qemu_x86_chipset_init();
+
 	if (target != rom_header) {
 		ulong start = get_timer(0);
 
diff --git a/include/qemu.h b/include/qemu.h
new file mode 100644
index 000000000000..d285b01ed80a
--- /dev/null
+++ b/include/qemu.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Generic QEMU header
+ *
+ * Copyright 2023 Google LLC
+ */
+
+#ifndef __QEMU_H
+#define __QEMU_H
+
+/* set up the chipset for QEMU so that video can be used */
+void qemu_x86_chipset_init(void);
+
+#endif
-- 
2.41.0.455.g037347b96a-goog