[PATCH v4 44/45] x86: video: Add a driver for QEMU bochs emulation
Simon Glass
sjg at chromium.org
Mon Jun 19 13:59:59 CEST 2023
Bochs is convenient with QEMU on x86 since it does not require a video
BIOS. Add a driver for it.
Signed-off-by: Simon Glass <sjg at chromium.org>
---
(no changes since v2)
Changes in v2:
- Bring in to qemu series
- Rebase to -next
- Drop unused of_match
- Fix Boschs typo
- Rename bochs_init_linear_fb() function to drop 'linear'
- Fix uninited variable
drivers/video/Kconfig | 30 ++++++++++
drivers/video/Makefile | 1 +
drivers/video/bochs.c | 123 +++++++++++++++++++++++++++++++++++++++++
drivers/video/bochs.h | 36 ++++++++++++
4 files changed, 190 insertions(+)
create mode 100644 drivers/video/bochs.c
create mode 100644 drivers/video/bochs.h
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 49762950719e..2ba4f5eac7f3 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -278,6 +278,36 @@ config VIDCONSOLE_AS_NAME
possible to update the environment, the breakage may be confusing for
users. This option will be removed around the end of 2020.
+config VIDEO_BOCHS
+ bool "Enable Bochs video emulation for QEMU"
+ depends on X86
+ help
+ Enable this to use the Bochs video support provided in the QEMU
+ emulator. This appears as a PCI device which U-Boot can set up to
+ provide a frame buffer.
+
+if VIDEO_BOCHS
+
+config VIDEO_BOCHS_SIZE_X
+ int "Width of display (X resolution)"
+ default 1280
+ help
+ Sets the width of the display.
+
+ These two options control the size of the display set up by QEMU.
+ Typical sizes are 1024 x 768 or 1280 x 1024.
+
+config VIDEO_BOCHS_SIZE_Y
+ int "High of display (Y resolution)"
+ default 1024
+ help
+ Sets the height of the display.
+
+ These two options control the size of the display set up by QEMU.
+ Typical sizes are 1024 x 768 or 1280 x 1024.
+
+endif
+
config VIDEO_COREBOOT
bool "Enable coreboot framebuffer driver support"
depends on X86
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index f99d7e3c3d90..a9263709084d 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_OSD) += video_osd-uclass.o
obj-$(CONFIG_SANDBOX_OSD) += sandbox_osd.o
obj-$(CONFIG_VIDEO_ARM_MALIDP) += mali_dp.o
obj-$(CONFIG_VIDEO_BCM2835) += bcm2835.o
+obj-$(CONFIG_VIDEO_BOCHS) += bochs.o
obj-$(CONFIG_VIDEO_BROADWELL_IGD) += broadwell_igd.o
obj-$(CONFIG_VIDEO_COREBOOT) += coreboot.o
obj-$(CONFIG_VIDEO_DW_HDMI) += dw_hdmi.o
diff --git a/drivers/video/bochs.c b/drivers/video/bochs.c
new file mode 100644
index 000000000000..2136b5119368
--- /dev/null
+++ b/drivers/video/bochs.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Modified from coreboot bochs.c
+ */
+
+#define LOG_CATEGORY UCLASS_VIDEO
+
+#include <common.h>
+#include <dm.h>
+#include <log.h>
+#include <pci.h>
+#include <video.h>
+#include <asm/io.h>
+#include <asm/mtrr.h>
+#include <linux/sizes.h>
+#include "bochs.h"
+
+static int xsize = CONFIG_VIDEO_BOCHS_SIZE_X;
+static int ysize = CONFIG_VIDEO_BOCHS_SIZE_Y;
+
+static void bochs_write(void *mmio, int index, int val)
+{
+ writew(val, mmio + MMIO_BASE + index * 2);
+}
+
+static int bochs_read(void *mmio, int index)
+{
+ return readw(mmio + MMIO_BASE + index * 2);
+}
+
+static void bochs_vga_write(int index, uint8_t val)
+{
+ outb(val, VGA_INDEX);
+}
+
+static int bochs_init_fb(struct udevice *dev)
+{
+ struct video_uc_plat *plat = dev_get_uclass_plat(dev);
+ struct video_priv *uc_priv = dev_get_uclass_priv(dev);
+ ulong fb;
+ void *mmio;
+ int id, mem;
+
+ log_debug("probing %s at PCI %x\n", dev->name, dm_pci_get_bdf(dev));
+ fb = dm_pci_read_bar32(dev, 0);
+ if (!fb)
+ return log_msg_ret("fb", -EIO);
+
+ /* MMIO bar supported since qemu 3.0+ */
+ mmio = dm_pci_map_bar(dev, PCI_BASE_ADDRESS_2, 0, 0, PCI_REGION_TYPE,
+ PCI_REGION_MEM);
+
+ if (!mmio)
+ return log_msg_ret("map", -EIO);
+
+ /* bochs dispi detection */
+ id = bochs_read(mmio, INDEX_ID);
+ if ((id & 0xfff0) != ID0) {
+ log_debug("ID mismatch\n");
+ return -EPROTONOSUPPORT;
+ }
+ mem = bochs_read(mmio, INDEX_VIDEO_MEMORY_64K) * SZ_64K;
+ log_debug("QEMU VGA: bochs @ %p: %d MiB FB at %lx\n", mmio, mem / SZ_1M,
+ fb);
+
+ uc_priv->xsize = xsize;
+ uc_priv->ysize = ysize;
+ uc_priv->bpix = VIDEO_BPP32;
+
+ /* setup video mode */
+ bochs_write(mmio, INDEX_ENABLE, 0);
+ bochs_write(mmio, INDEX_BANK, 0);
+ bochs_write(mmio, INDEX_BPP, VNBITS(uc_priv->bpix));
+ bochs_write(mmio, INDEX_XRES, xsize);
+ bochs_write(mmio, INDEX_YRES, ysize);
+ bochs_write(mmio, INDEX_VIRT_WIDTH, xsize);
+ bochs_write(mmio, INDEX_VIRT_HEIGHT, ysize);
+ bochs_write(mmio, INDEX_X_OFFSET, 0);
+ bochs_write(mmio, INDEX_Y_OFFSET, 0);
+ bochs_write(mmio, INDEX_ENABLE, ENABLED | LFB_ENABLED);
+
+ bochs_vga_write(0, 0x20); /* disable blanking */
+
+ plat->base = fb;
+
+ return 0;
+}
+
+static int bochs_video_probe(struct udevice *dev)
+{
+ int ret;
+
+ ret = bochs_init_fb(dev);
+ if (ret)
+ return log_ret(ret);
+
+ return 0;
+}
+
+static int bochs_video_bind(struct udevice *dev)
+{
+ struct video_uc_plat *uc_plat = dev_get_uclass_plat(dev);
+
+ /* Set the maximum supported resolution */
+ uc_plat->size = 2560 * 1600 * 4;
+ log_debug("%s: Frame buffer size %x\n", __func__, uc_plat->size);
+
+ return 0;
+}
+
+U_BOOT_DRIVER(bochs_video) = {
+ .name = "bochs_video",
+ .id = UCLASS_VIDEO,
+ .bind = bochs_video_bind,
+ .probe = bochs_video_probe,
+};
+
+static struct pci_device_id bochs_video_supported[] = {
+ { PCI_DEVICE(0x1234, 0x1111) },
+ { },
+};
+
+U_BOOT_PCI_DEVICE(bochs_video, bochs_video_supported);
diff --git a/drivers/video/bochs.h b/drivers/video/bochs.h
new file mode 100644
index 000000000000..4c8ec83a550e
--- /dev/null
+++ b/drivers/video/bochs.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Modified from coreboot bochs.c
+ */
+
+#ifndef __BOCHS_H
+#define __BOCHS_H
+
+#define VGA_INDEX 0x3c0
+
+#define IOPORT_INDEX 0x01ce
+#define IOPORT_DATA 0x01cf
+
+enum {
+ INDEX_ID,
+ INDEX_XRES,
+ INDEX_YRES,
+ INDEX_BPP,
+ INDEX_ENABLE,
+ INDEX_BANK,
+ INDEX_VIRT_WIDTH,
+ INDEX_VIRT_HEIGHT,
+ INDEX_X_OFFSET,
+ INDEX_Y_OFFSET,
+ INDEX_VIDEO_MEMORY_64K
+};
+
+#define ID0 0xb0c0
+
+#define ENABLED BIT(0)
+#define LFB_ENABLED BIT(6)
+#define NOCLEARMEM BIT(7)
+
+#define MMIO_BASE 0x500
+
+#endif
--
2.41.0.162.gfafddb0af9-goog
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