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video: Add helpers for decoding screen_info
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. v2: * return ssize_t from screen_info_resources() * don't call __screen_info_has_lfb() unnecessarily Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240212090736.11464-2-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann
parent
6b1f93ea34
commit
75fa9b7e37
@ -182,6 +182,7 @@ config MTK_ADSP_IPC
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config SYSFB
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bool
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select BOOT_VESA_SUPPORT
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select SCREEN_INFO
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config SYSFB_SIMPLEFB
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bool "Mark VGA/VBE/EFI FB as generic system framebuffer"
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@ -11,6 +11,10 @@ config APERTURE_HELPERS
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Support tracking and hand-over of aperture ownership. Required
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by graphics drivers for firmware-provided framebuffers.
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config SCREEN_INFO
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bool
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default n
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config STI_CORE
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bool
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depends on PARISC
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@ -1,11 +1,14 @@
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# SPDX-License-Identifier: GPL-2.0
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obj-$(CONFIG_APERTURE_HELPERS) += aperture.o
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obj-$(CONFIG_SCREEN_INFO) += screen_info.o
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obj-$(CONFIG_STI_CORE) += sticore.o
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obj-$(CONFIG_VGASTATE) += vgastate.o
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obj-$(CONFIG_VIDEO) += cmdline.o nomodeset.o
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obj-$(CONFIG_HDMI) += hdmi.o
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screen_info-y := screen_info_generic.o
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obj-$(CONFIG_VT) += console/
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obj-$(CONFIG_FB_STI) += console/
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obj-$(CONFIG_LOGO) += logo/
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146
drivers/video/screen_info_generic.c
Normal file
146
drivers/video/screen_info_generic.c
Normal file
@ -0,0 +1,146 @@
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/export.h>
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#include <linux/ioport.h>
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#include <linux/screen_info.h>
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#include <linux/string.h>
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static void resource_init_named(struct resource *r,
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resource_size_t start, resource_size_t size,
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const char *name, unsigned int flags)
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{
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memset(r, 0, sizeof(*r));
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r->start = start;
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r->end = start + size - 1;
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r->name = name;
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r->flags = flags;
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}
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static void resource_init_io_named(struct resource *r,
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resource_size_t start, resource_size_t size,
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const char *name)
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{
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resource_init_named(r, start, size, name, IORESOURCE_IO);
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}
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static void resource_init_mem_named(struct resource *r,
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resource_size_t start, resource_size_t size,
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const char *name)
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{
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resource_init_named(r, start, size, name, IORESOURCE_MEM);
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}
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static inline bool __screen_info_has_ega_gfx(unsigned int mode)
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{
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switch (mode) {
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case 0x0d: /* 320x200-4 */
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case 0x0e: /* 640x200-4 */
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case 0x0f: /* 640x350-1 */
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case 0x10: /* 640x350-4 */
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return true;
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default:
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return false;
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}
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}
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static inline bool __screen_info_has_vga_gfx(unsigned int mode)
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{
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switch (mode) {
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case 0x10: /* 640x480-1 */
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case 0x12: /* 640x480-4 */
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case 0x13: /* 320-200-8 */
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case 0x6a: /* 800x600-4 (VESA) */
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return true;
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default:
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return __screen_info_has_ega_gfx(mode);
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}
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}
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/**
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* screen_info_resources() - Get resources from screen_info structure
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* @si: the screen_info
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* @r: pointer to an array of resource structures
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* @num: number of elements in @r:
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*
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* Returns:
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* The number of resources stored in @r on success, or a negative errno code otherwise.
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*
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* A call to screen_info_resources() returns the resources consumed by the
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* screen_info's device or framebuffer. The result is stored in the caller-supplied
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* array @r with up to @num elements. The function returns the number of
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* initialized elements.
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*/
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ssize_t screen_info_resources(const struct screen_info *si, struct resource *r, size_t num)
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{
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struct resource *pos = r;
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unsigned int type = screen_info_video_type(si);
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u64 base, size;
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switch (type) {
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case VIDEO_TYPE_MDA:
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if (num > 0)
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resource_init_io_named(pos++, 0x3b0, 12, "mda");
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if (num > 1)
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resource_init_io_named(pos++, 0x3bf, 0x01, "mda");
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if (num > 2)
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resource_init_mem_named(pos++, 0xb0000, 0x2000, "mda");
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break;
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case VIDEO_TYPE_CGA:
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if (num > 0)
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resource_init_io_named(pos++, 0x3d4, 0x02, "cga");
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if (num > 1)
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resource_init_mem_named(pos++, 0xb8000, 0x2000, "cga");
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break;
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case VIDEO_TYPE_EGAM:
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if (num > 0)
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resource_init_io_named(pos++, 0x3bf, 0x10, "ega");
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if (num > 1)
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resource_init_mem_named(pos++, 0xb0000, 0x8000, "ega");
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break;
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case VIDEO_TYPE_EGAC:
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if (num > 0)
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resource_init_io_named(pos++, 0x3c0, 0x20, "ega");
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if (num > 1) {
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if (__screen_info_has_ega_gfx(si->orig_video_mode))
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resource_init_mem_named(pos++, 0xa0000, 0x10000, "ega");
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else
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resource_init_mem_named(pos++, 0xb8000, 0x8000, "ega");
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}
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break;
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case VIDEO_TYPE_VGAC:
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if (num > 0)
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resource_init_io_named(pos++, 0x3c0, 0x20, "vga+");
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if (num > 1) {
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if (__screen_info_has_vga_gfx(si->orig_video_mode))
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resource_init_mem_named(pos++, 0xa0000, 0x10000, "vga+");
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else
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resource_init_mem_named(pos++, 0xb8000, 0x8000, "vga+");
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}
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break;
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case VIDEO_TYPE_VLFB:
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case VIDEO_TYPE_EFI:
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base = __screen_info_lfb_base(si);
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if (!base)
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break;
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size = __screen_info_lfb_size(si, type);
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if (!size)
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break;
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if (num > 0)
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resource_init_mem_named(pos++, base, size, "lfb");
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break;
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case VIDEO_TYPE_PICA_S3:
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case VIDEO_TYPE_MIPS_G364:
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case VIDEO_TYPE_SGI:
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case VIDEO_TYPE_TGAC:
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case VIDEO_TYPE_SUN:
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case VIDEO_TYPE_SUNPCI:
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case VIDEO_TYPE_PMAC:
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default:
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/* not supported */
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return -EINVAL;
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}
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return pos - r;
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}
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EXPORT_SYMBOL(screen_info_resources);
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@ -4,6 +4,106 @@
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#include <uapi/linux/screen_info.h>
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/**
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* SCREEN_INFO_MAX_RESOURCES - maximum number of resources per screen_info
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*/
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#define SCREEN_INFO_MAX_RESOURCES 3
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struct resource;
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static inline bool __screen_info_has_lfb(unsigned int type)
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{
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return (type == VIDEO_TYPE_VLFB) || (type == VIDEO_TYPE_EFI);
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}
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static inline u64 __screen_info_lfb_base(const struct screen_info *si)
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{
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u64 lfb_base = si->lfb_base;
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if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
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lfb_base |= (u64)si->ext_lfb_base << 32;
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return lfb_base;
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}
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static inline u64 __screen_info_lfb_size(const struct screen_info *si, unsigned int type)
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{
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u64 lfb_size = si->lfb_size;
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if (type == VIDEO_TYPE_VLFB)
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lfb_size <<= 16;
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return lfb_size;
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}
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static inline unsigned int __screen_info_video_type(unsigned int type)
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{
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switch (type) {
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case VIDEO_TYPE_MDA:
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case VIDEO_TYPE_CGA:
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case VIDEO_TYPE_EGAM:
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case VIDEO_TYPE_EGAC:
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case VIDEO_TYPE_VGAC:
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case VIDEO_TYPE_VLFB:
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case VIDEO_TYPE_PICA_S3:
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case VIDEO_TYPE_MIPS_G364:
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case VIDEO_TYPE_SGI:
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case VIDEO_TYPE_TGAC:
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case VIDEO_TYPE_SUN:
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case VIDEO_TYPE_SUNPCI:
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case VIDEO_TYPE_PMAC:
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case VIDEO_TYPE_EFI:
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return type;
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default:
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return 0;
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}
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}
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/**
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* screen_info_video_type() - Decodes the video type from struct screen_info
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* @si: an instance of struct screen_info
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*
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* Returns:
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* A VIDEO_TYPE_ constant representing si's type of video display, or 0 otherwise.
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*/
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static inline unsigned int screen_info_video_type(const struct screen_info *si)
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{
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unsigned int type;
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// check if display output is on
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if (!si->orig_video_isVGA)
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return 0;
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// check for a known VIDEO_TYPE_ constant
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type = __screen_info_video_type(si->orig_video_isVGA);
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if (type)
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return si->orig_video_isVGA;
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// check if text mode has been initialized
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if (!si->orig_video_lines || !si->orig_video_cols)
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return 0;
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// 80x25 text, mono
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if (si->orig_video_mode == 0x07) {
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if ((si->orig_video_ega_bx & 0xff) != 0x10)
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return VIDEO_TYPE_EGAM;
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else
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return VIDEO_TYPE_MDA;
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}
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// EGA/VGA, 16 colors
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if ((si->orig_video_ega_bx & 0xff) != 0x10) {
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if (si->orig_video_isVGA)
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return VIDEO_TYPE_VGAC;
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else
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return VIDEO_TYPE_EGAC;
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}
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// the rest...
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return VIDEO_TYPE_CGA;
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}
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ssize_t screen_info_resources(const struct screen_info *si, struct resource *r, size_t num);
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extern struct screen_info screen_info;
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#endif /* _SCREEN_INFO_H */
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