[Qemu-devel] [PATCH] add bochs dispi interface framebuffer driver

[Gerd Hoffmann]

This patchs adds a frame buffer driver for (virtual/emulated) vga cards
implementing the bochs dispi interface.  Supported hardware are the
bochs vga card with vbe extension and the qemu standard vga.

The driver uses a fixed depth of 32bpp.  Otherwise it supports the full
(but small) feature set of the bochs dispi interface:  Resolution
switching and display panning.  It is tweaked to maximize fbcon speed,
so you'll get the comfort of the framebuffer console in kvm guests
without performance penalty.

Signed-off-by: Gerd Hoffmann <address@hidden>
---
 drivers/video/Kconfig   |   18 +++
 drivers/video/Makefile  |    1 +
 drivers/video/bochsfb.c |  385 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 404 insertions(+), 0 deletions(-)
 create mode 100644 drivers/video/bochsfb.c

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 6ca0c40..4d21f90 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -286,6 +286,24 @@ config FB_CIRRUS
          Say N unless you have such a graphics board or plan to get one
          before you next recompile the kernel.
 
+config FB_BOCHS
+       tristate "Bochs dispi interface support"
+       depends on FB && PCI
+       select FB_CFB_FILLRECT
+       select FB_CFB_COPYAREA
+       select FB_CFB_IMAGEBLIT
+       ---help---
+         This is the frame buffer driver for (virtual/emulated) vga
+          cards implementing the bochs dispi interface.  Supported
+          hardware are the bochs vga card with vbe extension and the
+          qemu standard vga.
+
+          The driver handles the PCI variants only.  It uses a fixed
+          depth of 32bpp, anything else doesn't make sense these days.
+
+          Say Y here if you plan to run the kernel in a virtual machine
+          emulated by bochs or qemu.
+
 config FB_PM2
        tristate "Permedia2 support"
        depends on FB && ((AMIGA && BROKEN) || PCI)
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 1426068..a065ad3 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -99,6 +99,7 @@ obj-$(CONFIG_FB_ARMCLCD)        += amba-clcd.o
 obj-$(CONFIG_FB_68328)            += 68328fb.o
 obj-$(CONFIG_FB_GBE)              += gbefb.o
 obj-$(CONFIG_FB_CIRRUS)                  += cirrusfb.o
+obj-$(CONFIG_FB_BOCHS)           += bochsfb.o
 obj-$(CONFIG_FB_ASILIANT)        += asiliantfb.o
 obj-$(CONFIG_FB_PXA)             += pxafb.o
 obj-$(CONFIG_FB_PXA168)                  += pxa168fb.o
diff --git a/drivers/video/bochsfb.c b/drivers/video/bochsfb.c
new file mode 100644
index 0000000..18a94dc
--- /dev/null
+++ b/drivers/video/bochsfb.c
@@ -0,0 +1,385 @@
+/*
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License. See the file COPYING in the main directory of this archive for
+ *  more details.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/fb.h>
+#include <linux/pm.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/console.h>
+#include <asm/io.h>
+
+#define VBE_DISPI_IOPORT_INDEX           0x01CE
+#define VBE_DISPI_IOPORT_DATA            0x01CF
+
+#define VBE_DISPI_INDEX_ID               0x0
+#define VBE_DISPI_INDEX_XRES             0x1
+#define VBE_DISPI_INDEX_YRES             0x2
+#define VBE_DISPI_INDEX_BPP              0x3
+#define VBE_DISPI_INDEX_ENABLE           0x4
+#define VBE_DISPI_INDEX_BANK             0x5
+#define VBE_DISPI_INDEX_VIRT_WIDTH       0x6
+#define VBE_DISPI_INDEX_VIRT_HEIGHT      0x7
+#define VBE_DISPI_INDEX_X_OFFSET         0x8
+#define VBE_DISPI_INDEX_Y_OFFSET         0x9
+#define VBE_DISPI_INDEX_VIDEO_MEMORY_64K 0xa
+
+#define VBE_DISPI_ID0                    0xB0C0
+#define VBE_DISPI_ID1                    0xB0C1
+#define VBE_DISPI_ID2                    0xB0C2
+#define VBE_DISPI_ID3                    0xB0C3
+#define VBE_DISPI_ID4                    0xB0C4
+#define VBE_DISPI_ID5                    0xB0C5
+
+#define VBE_DISPI_DISABLED               0x00
+#define VBE_DISPI_ENABLED                0x01
+#define VBE_DISPI_GETCAPS                0x02
+#define VBE_DISPI_8BIT_DAC               0x20
+#define VBE_DISPI_LFB_ENABLED            0x40
+#define VBE_DISPI_NOCLEARMEM             0x80
+
+enum bochs_types {
+       BOCHS_QEMU_STDVGA,
+       BOCHS_UNKNOWN,
+};
+
+static const char *bochs_names[] = {
+       [ BOCHS_QEMU_STDVGA ] = "QEMU standard vga",
+       [ BOCHS_UNKNOWN ]     = "unknown",
+};
+
+static struct fb_fix_screeninfo bochsfb_fix __devinitdata = {
+       .id          = "bochsfb",
+       .type        = FB_TYPE_PACKED_PIXELS,
+       .visual      = FB_VISUAL_TRUECOLOR,
+       .accel       = FB_ACCEL_NONE,
+       .xpanstep    = 1,
+       .ypanstep    = 1,
+};
+
+static struct fb_var_screeninfo bochsfb_var __devinitdata = {
+       .xres           = 1024,
+       .yres           = 768,
+       .bits_per_pixel = 32,
+#ifdef __BIG_ENDIAN
+       .transp         = { .length = 8, .offset =  0 },
+       .red            = { .length = 8, .offset =  8 },
+       .green          = { .length = 8, .offset = 16 },
+       .blue           = { .length = 8, .offset = 24 },
+#else
+       .transp         = { .length = 8, .offset = 24 },
+       .red            = { .length = 8, .offset = 16 },
+       .green          = { .length = 8, .offset =  8 },
+       .blue           = { .length = 8, .offset =  0 },
+#endif
+       .height         = -1,
+       .width          = -1,
+       .vmode          = FB_VMODE_NONINTERLACED,
+       .pixclock       = 10000,
+       .left_margin    = 16,
+       .right_margin   = 16,
+       .upper_margin   = 16,
+       .lower_margin   = 16,
+       .hsync_len      = 8,
+       .vsync_len      = 8,
+};
+
+static char *mode __devinitdata;
+module_param(mode, charp, 0);
+MODULE_PARM_DESC(mode, "Initial video mode e.g. '648x480'");
+
+static u16 bochs_read(u16 reg)
+{
+       outw(reg, VBE_DISPI_IOPORT_INDEX);
+       return inw(VBE_DISPI_IOPORT_DATA);
+}
+
+static void bochs_write(u16 reg, u16 val)
+{
+       outw(reg, VBE_DISPI_IOPORT_INDEX);
+       outw(val, VBE_DISPI_IOPORT_DATA);
+}
+
+static int bochsfb_check_var(struct fb_var_screeninfo *var,
+                            struct fb_info *info)
+{
+       uint32_t x,y, xv,yv, pixels;
+
+       if (var->bits_per_pixel != 32 ||
+           var->xres > 65535 ||
+           var->xres_virtual > 65535 ||
+           (var->vmode & FB_VMODE_MASK) != FB_VMODE_NONINTERLACED)
+               return -EINVAL;
+
+       x  = var->xres & ~0x0f;
+       y  = var->yres & ~0x03;
+       xv = var->xres_virtual & ~0x0f;
+       yv = var->yres_virtual & ~0x03;
+       if (xv < x)
+               xv = x;
+       pixels = info->fix.smem_len * 8 / info->var.bits_per_pixel;
+       yv = pixels / xv;
+       if (y > yv)
+               return -EINVAL;
+
+       var->xres = x;
+       var->yres = y;
+       var->xres_virtual = xv;
+       var->yres_virtual = yv;
+       var->xoffset = 0;
+       var->yoffset = 0;
+
+       return 0;
+}
+
+static int bochsfb_set_par(struct fb_info *info)
+{
+       dev_dbg(info->dev, "set mode: real: %dx%d, virtual: %dx%d\n",
+               info->var.xres, info->var.yres,
+               info->var.xres_virtual, info->var.yres_virtual);
+
+       info->fix.line_length = info->var.xres * info->var.bits_per_pixel / 8;
+
+       bochs_write(VBE_DISPI_INDEX_BPP,         info->var.bits_per_pixel);
+       bochs_write(VBE_DISPI_INDEX_XRES,        info->var.xres);
+       bochs_write(VBE_DISPI_INDEX_YRES,        info->var.yres);
+       bochs_write(VBE_DISPI_INDEX_BANK,        0);
+       bochs_write(VBE_DISPI_INDEX_VIRT_WIDTH,  info->var.xres_virtual);
+       bochs_write(VBE_DISPI_INDEX_VIRT_HEIGHT, info->var.yres_virtual);
+       bochs_write(VBE_DISPI_INDEX_X_OFFSET,    info->var.xoffset);
+       bochs_write(VBE_DISPI_INDEX_Y_OFFSET,    info->var.yoffset);
+
+       bochs_write(VBE_DISPI_INDEX_ENABLE,
+                   VBE_DISPI_ENABLED | VBE_DISPI_LFB_ENABLED);
+       return 0;
+}
+
+static int bochsfb_setcolreg(unsigned regno, unsigned red, unsigned green,
+                            unsigned blue, unsigned transp,
+                            struct fb_info *info)
+{
+       if (regno < 16 && info->var.bits_per_pixel == 32) {
+               red   >>= 8;
+               green >>= 8;
+               blue  >>= 8;
+               ((u32 *)(info->pseudo_palette))[regno] =
+                       (red   << info->var.red.offset)   |
+                       (green << info->var.green.offset) |
+                       (blue  << info->var.blue.offset);
+       }
+       return 0;
+}
+
+static int bochsfb_pan_display(struct fb_var_screeninfo *var,
+                              struct fb_info *info)
+{
+       bochs_write(VBE_DISPI_INDEX_X_OFFSET, var->xoffset);
+       bochs_write(VBE_DISPI_INDEX_Y_OFFSET, var->yoffset);
+       return 0;
+}
+
+static struct fb_ops bochsfb_ops = {
+       .owner          = THIS_MODULE,
+       .fb_check_var   = bochsfb_check_var,
+       .fb_set_par     = bochsfb_set_par,
+       .fb_setcolreg   = bochsfb_setcolreg,
+       .fb_pan_display = bochsfb_pan_display,
+       .fb_fillrect    = cfb_fillrect,
+       .fb_copyarea    = cfb_copyarea,
+       .fb_imageblit   = cfb_imageblit,
+};
+
+static int __devinit
+bochsfb_pci_init(struct pci_dev *dp, const struct pci_device_id *ent)
+{
+       struct fb_info *p;
+       unsigned long addr, size, mem;
+       u16 id;
+       int rc = -ENODEV;
+
+       id = bochs_read(VBE_DISPI_INDEX_ID);;
+       mem = bochs_read(VBE_DISPI_INDEX_VIDEO_MEMORY_64K) * 64 * 1024;
+       dev_info(&dp->dev,"Found bochs VGA, ID 0x%x, mem %ldk, type \"%s\".\n",
+                id, mem / 1024, bochs_names[ent->driver_data]);
+       if ((id & 0xfff0) != VBE_DISPI_ID0) {
+               dev_err(&dp->dev, "ID mismatch\n");
+               goto err_out;
+       }
+
+       if (pci_enable_device(dp) < 0) {
+               dev_err(&dp->dev, "Cannot enable PCI device\n");
+               goto err_out;
+       }
+
+       if ((dp->resource[0].flags & IORESOURCE_MEM) == 0)
+               goto err_disable;
+       addr = pci_resource_start(dp, 0);
+       size = pci_resource_len(dp, 0);
+       if (addr == 0)
+               goto err_disable;
+       if (size != mem) {
+               dev_err(&dp->dev, "Size mismatch: pci=%ld, bochs=%ld\n", size, 
mem);
+               size = min(size, mem);
+       }
+
+       p = framebuffer_alloc(0, &dp->dev);
+       if (p == NULL) {
+               dev_err(&dp->dev, "Cannot allocate framebuffer structure\n");
+               rc = -ENOMEM;
+               goto err_disable;
+       }
+
+       if (pci_request_region(dp, 0, "bochsfb") != 0) {
+               dev_err(&dp->dev, "Cannot request framebuffer\n");
+               rc = -EBUSY;
+               goto err_release_fb;
+       }
+
+       if (!request_region(VBE_DISPI_IOPORT_INDEX, 2, "bochsfb")) {
+               dev_err(&dp->dev, "Cannot request ioports\n");
+               rc = -EBUSY;
+               goto err_release_pci;
+       }
+
+       p->screen_base = ioremap(addr, size);
+       if (p->screen_base == NULL) {
+               dev_err(&dp->dev, "Cannot map framebuffer\n");
+               rc = -ENOMEM;
+               goto err_release_ports;
+       }
+       memset(p->screen_base, 0, size);
+
+       pci_set_drvdata(dp, p);
+       p->fbops = &bochsfb_ops;
+       p->flags = FBINFO_FLAG_DEFAULT
+               | FBINFO_READS_FAST
+               | FBINFO_HWACCEL_XPAN
+               | FBINFO_HWACCEL_YPAN;
+       p->pseudo_palette = kmalloc(sizeof(u32) * 16, GFP_KERNEL);
+       p->fix = bochsfb_fix;
+       p->fix.smem_start = addr;
+       p->fix.smem_len = size;
+
+       p->var = bochsfb_var;
+       bochsfb_check_var(&p->var, p);
+       if (mode) {
+               fb_find_mode(&p->var, p, mode, NULL, 0, NULL, 32);
+       }
+
+       if (register_framebuffer(p) < 0) {
+               dev_err(&dp->dev,"Framebuffer failed to register\n");
+               goto err_unmap;
+       }
+
+       dev_info(&dp->dev,"fb%d: bochs VGA frame buffer initialized.\n",
+                p->node);
+
+       return 0;
+
+ err_unmap:
+       iounmap(p->screen_base);
+ err_release_ports:
+       release_region(VBE_DISPI_IOPORT_INDEX, 2);
+ err_release_pci:
+       pci_release_region(dp, 0);
+ err_release_fb:
+       framebuffer_release(p);
+ err_disable:
+ err_out:
+       return rc;
+}
+
+static void __devexit bochsfb_remove(struct pci_dev *dp)
+{
+       struct fb_info *p = pci_get_drvdata(dp);
+
+       if (p->screen_base == NULL)
+               return;
+       unregister_framebuffer(p);
+       iounmap(p->screen_base);
+       p->screen_base = NULL;
+       release_region(VBE_DISPI_IOPORT_INDEX, 2);
+       pci_release_region(dp, 0);
+       kfree(p->pseudo_palette);
+       framebuffer_release(p);
+}
+
+static struct pci_device_id bochsfb_pci_tbl[] = {
+       {
+               .vendor      = 0x1234,
+               .device      = 0x1111,
+               .subvendor   = 0x1af4,
+               .subdevice   = 0x1100,
+               .driver_data = BOCHS_QEMU_STDVGA,
+       },
+       {
+               .vendor      = 0x1234,
+               .device      = 0x1111,
+               .subvendor   = PCI_ANY_ID,
+               .subdevice   = PCI_ANY_ID,
+               .driver_data = BOCHS_UNKNOWN,
+       },
+       { /* end of list */ }
+};
+
+MODULE_DEVICE_TABLE(pci, bochsfb_pci_tbl);
+
+static struct pci_driver bochsfb_driver = {
+       .name =         "bochsfb",
+       .id_table =     bochsfb_pci_tbl,
+       .probe =        bochsfb_pci_init,
+       .remove =       __devexit_p(bochsfb_remove),
+};
+
+#ifndef MODULE
+static int __init bochsfb_setup(char *options)
+{
+       char *this_opt;
+
+       if (!options || !*options)
+               return 0;
+
+       while ((this_opt = strsep(&options, ",")) != NULL) {
+               if (!*this_opt)
+                       continue;
+               if (!strncmp(this_opt, "mode:", 5))
+                       mode = this_opt + 5;
+               else
+                       mode = this_opt;
+       }
+       return 0;
+}
+#endif
+
+int __init bochs_init(void)
+{
+#ifndef MODULE
+       char *option = NULL;
+
+       if (fb_get_options("bochsfb", &option))
+               return -ENODEV;
+       bochsfb_setup(option);
+#endif
+       return pci_register_driver(&bochsfb_driver);
+}
+
+module_init(bochs_init);
+
+static void __exit bochsfb_exit(void)
+{
+       pci_unregister_driver(&bochsfb_driver);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Gerd Hoffmann <address@hidden>");
+MODULE_DESCRIPTION("bochs dispi interface framebuffer driver");
-- 
1.7.1