The plain values as stored in struct screen_info need to be decoded
before being used. Add helpers that decode the type of video output
and the framebuffer I/O aperture.
Old or non-x86 systems may not set the type of video directly, but
only indicate the presence by storing 0x01 in orig_video_isVGA. The
decoding logic in screen_info_video_type() takes this into account.
It then follows similar code in vgacon's vgacon_startup() to detect
the video type from the given values.
A call to screen_info_resources() returns all known resources of the
given screen_info. The resources' values have been taken from existing
code in vgacon and vga16fb. These drivers can later be converted to
use the new interfaces.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/firmware/Kconfig | 1 +
drivers/video/Kconfig | 4 +
drivers/video/Makefile | 3 +
drivers/video/screen_info_generic.c | 148 ++++++++++++++++++++++++++++
include/linux/screen_info.h | 100 +++++++++++++++++++
5 files changed, 256 insertions(+)
create mode 100644 drivers/video/screen_info_generic.c
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 4a98a859d44d..deba323178cc 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -191,6 +191,7 @@ config MTK_ADSP_IPC
config SYSFB
bool
select BOOT_VESA_SUPPORT
+ select SCREEN_INFO
config SYSFB_SIMPLEFB
bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index b694d7669d32..1eb755a94940 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -11,6 +11,10 @@ config APERTURE_HELPERS
Support tracking and hand-over of aperture ownership. Required
by graphics drivers for firmware-provided framebuffers.
+config SCREEN_INFO
+ bool
+ default n
+
config STI_CORE
bool
depends on PARISC
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 6bbc03950899..b929b664d52c 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -1,12 +1,15 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_APERTURE_HELPERS) += aperture.o
+obj-$(CONFIG_SCREEN_INFO) += screen_info.o
obj-$(CONFIG_STI_CORE) += sticore.o
obj-$(CONFIG_VGASTATE) += vgastate.o
obj-$(CONFIG_VIDEO_CMDLINE) += cmdline.o
obj-$(CONFIG_VIDEO_NOMODESET) += nomodeset.o
obj-$(CONFIG_HDMI) += hdmi.o
+screen_info-y := screen_info_generic.o
+
obj-$(CONFIG_VT) += console/
obj-$(CONFIG_FB_STI) += console/
obj-$(CONFIG_LOGO) += logo/
diff --git a/drivers/video/screen_info_generic.c b/drivers/video/screen_info_generic.c
new file mode 100644
index 000000000000..4be26941b2d9
--- /dev/null
+++ b/drivers/video/screen_info_generic.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/export.h>
+#include <linux/ioport.h>
+#include <linux/screen_info.h>
+#include <linux/string.h>
+
+static void resource_init_named(struct resource *r,
+ resource_size_t start, resource_size_t size,
+ const char *name, unsigned int flags)
+{
+ memset(r, 0, sizeof(*r));
+
+ r->start = start;
+ r->end = start + size - 1;
+ r->name = name;
+ r->flags = flags;
+}
+
+static void resource_init_io_named(struct resource *r,
+ resource_size_t start, resource_size_t size,
+ const char *name)
+{
+ resource_init_named(r, start, size, name, IORESOURCE_IO);
+}
+
+static void resource_init_mem_named(struct resource *r,
+ resource_size_t start, resource_size_t size,
+ const char *name)
+{
+ resource_init_named(r, start, size, name, IORESOURCE_MEM);
+}
+
+static inline bool __screen_info_has_ega_gfx(unsigned int mode)
+{
+ switch (mode) {
+ case 0x0d: /* 320x200-4 */
+ case 0x0e: /* 640x200-4 */
+ case 0x0f: /* 640x350-1 */
+ case 0x10: /* 640x350-4 */
+ return true;
+ default:
+ return false;
+ }
+}
+
+static inline bool __screen_info_has_vga_gfx(unsigned int mode)
+{
+ switch (mode) {
+ case 0x10: /* 640x480-1 */
+ case 0x12: /* 640x480-4 */
+ case 0x13: /* 320-200-8 */
+ case 0x6a: /* 800x600-4 (VESA) */
+ return true;
+ default:
+ return __screen_info_has_ega_gfx(mode);
+ }
+}
+
+/**
+ * screen_info_resources() - Get resources from screen_info structure
+ * @si: the screen_info
+ * @r: pointer to an array of resource structures
+ * @num: number of elements in @r:
+ *
+ * Returns:
+ * The number of resources stored in @r on success, or a negative errno code otherwise.
+ *
+ * A call to screen_info_resources() returns the resources consumed by the
+ * screen_info's device or framebuffer. The result is stored in the caller-supplied
+ * array @r with up to @num elements. The function returns the number of
+ * initialized elements.
+ */
+int screen_info_resources(const struct screen_info *si, struct resource *r, size_t num)
+{
+ struct resource *pos = r;
+ unsigned int type = screen_info_video_type(si);
+ u64 base, size;
+
+ switch (type) {
+ case VIDEO_TYPE_MDA:
+ if (num > 0)
+ resource_init_io_named(pos++, 0x3b0, 12, "mda");
+ if (num > 1)
+ resource_init_io_named(pos++, 0x3bf, 0x01, "mda");
+ if (num > 2)
+ resource_init_mem_named(pos++, 0xb0000, 0x2000, "mda");
+ break;
+ case VIDEO_TYPE_CGA:
+ if (num > 0)
+ resource_init_io_named(pos++, 0x3d4, 0x02, "cga");
+ if (num > 1)
+ resource_init_mem_named(pos++, 0xb8000, 0x2000, "cga");
+ break;
+ case VIDEO_TYPE_EGAM:
+ if (num > 0)
+ resource_init_io_named(pos++, 0x3bf, 0x10, "ega");
+ if (num > 1)
+ resource_init_mem_named(pos++, 0xb0000, 0x8000, "ega");
+ break;
+ case VIDEO_TYPE_EGAC:
+ if (num > 0)
+ resource_init_io_named(pos++, 0x3c0, 0x20, "ega");
+ if (num > 1) {
+ if (__screen_info_has_ega_gfx(si->orig_video_mode))
+ resource_init_mem_named(pos++, 0xa0000, 0x10000, "ega");
+ else
+ resource_init_mem_named(pos++, 0xb8000, 0x8000, "ega");
+ }
+ break;
+ case VIDEO_TYPE_VGAC:
+ if (num > 0)
+ resource_init_io_named(pos++, 0x3c0, 0x20, "vga+");
+ if (num > 1) {
+ if (__screen_info_has_vga_gfx(si->orig_video_mode))
+ resource_init_mem_named(pos++, 0xa0000, 0x10000, "vga+");
+ else
+ resource_init_mem_named(pos++, 0xb8000, 0x8000, "vga+");
+ }
+ break;
+ case VIDEO_TYPE_VLFB:
+ case VIDEO_TYPE_EFI:
+ if (!__screen_info_has_lfb(type))
+ break;
+ base = __screen_info_lfb_base(si);
+ if (!base)
+ break;
+ size = __screen_info_lfb_size(si, type);
+ if (!size)
+ break;
+ if (num > 0)
+ resource_init_mem_named(pos++, base, size, "lfb");
+ break;
+ case VIDEO_TYPE_PICA_S3:
+ case VIDEO_TYPE_MIPS_G364:
+ case VIDEO_TYPE_SGI:
+ case VIDEO_TYPE_TGAC:
+ case VIDEO_TYPE_SUN:
+ case VIDEO_TYPE_SUNPCI:
+ case VIDEO_TYPE_PMAC:
+ default:
+ /* not supported */
+ return -EINVAL;
+ }
+
+ return pos - r;
+}
+EXPORT_SYMBOL(screen_info_resources);
diff --git a/include/linux/screen_info.h b/include/linux/screen_info.h
index eab7081392d5..d4d45395df19 100644
--- a/include/linux/screen_info.h
+++ b/include/linux/screen_info.h
@@ -4,6 +4,106 @@
#include <uapi/linux/screen_info.h>
+/**
+ * SCREEN_INFO_MAX_RESOURCES - maximum number of resources per screen_info
+ */
+#define SCREEN_INFO_MAX_RESOURCES 3
+
+struct resource;
+
+static inline bool __screen_info_has_lfb(unsigned int type)
+{
+ return (type == VIDEO_TYPE_VLFB) || (type == VIDEO_TYPE_EFI);
+}
+
+static inline u64 __screen_info_lfb_base(const struct screen_info *si)
+{
+ u64 lfb_base = si->lfb_base;
+
+ if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+ lfb_base |= (u64)si->ext_lfb_base << 32;
+
+ return lfb_base;
+}
+
+static inline u64 __screen_info_lfb_size(const struct screen_info *si, unsigned int type)
+{
+ u64 lfb_size = si->lfb_size;
+
+ if (type == VIDEO_TYPE_VLFB)
+ lfb_size <<= 16;
+ return lfb_size;
+}
+
+static inline unsigned int __screen_info_video_type(unsigned int type)
+{
+ switch (type) {
+ case VIDEO_TYPE_MDA:
+ case VIDEO_TYPE_CGA:
+ case VIDEO_TYPE_EGAM:
+ case VIDEO_TYPE_EGAC:
+ case VIDEO_TYPE_VGAC:
+ case VIDEO_TYPE_VLFB:
+ case VIDEO_TYPE_PICA_S3:
+ case VIDEO_TYPE_MIPS_G364:
+ case VIDEO_TYPE_SGI:
+ case VIDEO_TYPE_TGAC:
+ case VIDEO_TYPE_SUN:
+ case VIDEO_TYPE_SUNPCI:
+ case VIDEO_TYPE_PMAC:
+ case VIDEO_TYPE_EFI:
+ return type;
+ default:
+ return 0;
+ }
+}
+
+/**
+ * screen_info_video_type() - Decodes the video type from struct screen_info
+ * @si: an instance of struct screen_info
+ *
+ * Returns:
+ * A VIDEO_TYPE_ constant representing si's type of video display, or 0 otherwise.
+ */
+static inline unsigned int screen_info_video_type(const struct screen_info *si)
+{
+ unsigned int type;
+
+ // check if display output is on
+ if (!si->orig_video_isVGA)
+ return 0;
+
+ // check for a known VIDEO_TYPE_ constant
+ type = __screen_info_video_type(si->orig_video_isVGA);
+ if (type)
+ return si->orig_video_isVGA;
+
+ // check if text mode has been initialized
+ if (!si->orig_video_lines || !si->orig_video_cols)
+ return 0;
+
+ // 80x25 text, mono
+ if (si->orig_video_mode == 0x07) {
+ if ((si->orig_video_ega_bx & 0xff) != 0x10)
+ return VIDEO_TYPE_EGAM;
+ else
+ return VIDEO_TYPE_MDA;
+ }
+
+ // EGA/VGA, 16 colors
+ if ((si->orig_video_ega_bx & 0xff) != 0x10) {
+ if (si->orig_video_isVGA)
+ return VIDEO_TYPE_VGAC;
+ else
+ return VIDEO_TYPE_EGAC;
+ }
+
+ // the rest...
+ return VIDEO_TYPE_CGA;
+}
+
+int screen_info_resources(const struct screen_info *si, struct resource *r, size_t num);
+
extern struct screen_info screen_info;
#endif /* _SCREEN_INFO_H */
--
2.43.0
