[PATCH v2 3/3] efi: earlycon: Add support for generic framebuffers and move to console subsystem

Markuss Broks
2022-08-06T16:35:00Z

Add early console support for generic linear framebuffer devices.
This driver supports probing from cmdline early parameters
or from the device-tree using information in simple-framebuffer node.
The EFI functionality should be retained in whole.
The driver was disabled on ARM because of a bug in early_ioremap
implementation on ARM and on IA64 because of lack of early_memremap_prot.

Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
---
.../admin-guide/kernel-parameters.txt | 12 +-
MAINTAINERS | 5 +
drivers/firmware/efi/Kconfig | 7 +-
drivers/firmware/efi/Makefile | 1 -
drivers/firmware/efi/earlycon.c | 246 --------------
drivers/video/console/Kconfig | 11 +
drivers/video/console/Makefile | 1 +
drivers/video/console/earlycon.c | 305 ++++++++++++++++++
8 files changed, 332 insertions(+), 256 deletions(-)
delete mode 100644 drivers/firmware/efi/earlycon.c
create mode 100644 drivers/video/console/earlycon.c

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 8090130b544b0701237a7b657a29c83c000a60f4..bccb1ac8978eb5cf7e2bb20834b1881b27040666 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1281,12 +1281,9 @@
specified address. The serial port must already be
setup and configured. Options are not yet supported.

- efifb,[options]
+ efifb
Start an early, unaccelerated console on the EFI
- memory mapped framebuffer (if available). On cache
- coherent non-x86 systems that use system memory for
- the framebuffer, pass the 'ram' option so that it is
- mapped with the correct attributes.
+ memory mapped framebuffer (if available).

linflex,<addr>
Use early console provided by Freescale LINFlexD UART
@@ -1294,6 +1291,11 @@
address must be provided, and the serial port must
already be setup and configured.

+ simplefb,<addr>,<width>x<height>x<bpp>
+ Use early console with simple framebuffer that is
+ pre-initialized by firmware. A valid base address,
+ width, height and pixel size must be provided.
+
earlyprintk= [X86,SH,ARM,M68k,S390]
earlyprintk=vga
earlyprintk=sclp
diff --git a/MAINTAINERS b/MAINTAINERS
index 1fc9ead83d2aa3e60ccc4cfa8ee16df09ef579bf..af8b8e289483b6a264d477145061bd0e0ba34a25 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7033,6 +7033,11 @@ Q: http://patchwork.linuxtv.org/project/linux-media/list/
T: git git://linuxtv.org/anttip/media_tree.git
F: drivers/media/tuners/e4000*

+EARLY CONSOLE FRAMEBUFFER DRIVER
+M: Markuss Broks <markuss.broks@gmail.com>
+S: Maintained
+F: drivers/video/console/earlycon.c
+
EARTH_PT1 MEDIA DRIVER
M: Akihiro Tsukada <tskd08@gmail.com>
L: linux-media@vger.kernel.org
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 7aa4717cdcac46f91dd202f868c463388eb02735..ea76ccfb9bcd8ba44ddca06052eaa442ed6c30f7 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -259,10 +259,9 @@ config EFI_DISABLE_PCI_DMA
may be used to override this option.

config EFI_EARLYCON
- def_bool y
- depends on SERIAL_EARLYCON && !ARM && !IA64
- select FONT_SUPPORT
- select ARCH_USE_MEMREMAP_PROT
+ bool "EFI early console support"
+ select FB_EARLYCON
+ default y

config EFI_CUSTOM_SSDT_OVERLAYS
bool "Load custom ACPI SSDT overlay from an EFI variable"
diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index c02ff25dd47707090a2ab86ee4f330e467f878f5..64eea61fbb43d76ec2d5416d467dfbb9aa21bda0 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -44,6 +44,5 @@ obj-$(CONFIG_ARM64) += $(arm-obj-y)
riscv-obj-$(CONFIG_EFI) := efi-init.o riscv-runtime.o
obj-$(CONFIG_RISCV) += $(riscv-obj-y)
obj-$(CONFIG_EFI_CAPSULE_LOADER) += capsule-loader.o
-obj-$(CONFIG_EFI_EARLYCON) += earlycon.o
obj-$(CONFIG_UEFI_CPER_ARM) += cper-arm.o
obj-$(CONFIG_UEFI_CPER_X86) += cper-x86.o
diff --git a/drivers/firmware/efi/earlycon.c b/drivers/firmware/efi/earlycon.c
deleted file mode 100644
index a52236e11e5f73ddea5bb1f42ca2ca7c42425dab..0000000000000000000000000000000000000000
--- a/drivers/firmware/efi/earlycon.c
+++ /dev/null
@@ -1,246 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) 2013 Intel Corporation; author Matt Fleming
- */
-
-#include <linux/console.h>
-#include <linux/efi.h>
-#include <linux/font.h>
-#include <linux/io.h>
-#include <linux/kernel.h>
-#include <linux/serial_core.h>
-#include <linux/screen_info.h>
-
-#include <asm/early_ioremap.h>
-
-static const struct console *earlycon_console __initdata;
-static const struct font_desc *font;
-static u32 efi_x, efi_y;
-static u64 fb_base;
-static bool fb_wb;
-static void *efi_fb;
-
-/*
- * EFI earlycon needs to use early_memremap() to map the framebuffer.
- * But early_memremap() is not usable for 'earlycon=efifb keep_bootcon',
- * memremap() should be used instead. memremap() will be available after
- * paging_init() which is earlier than initcall callbacks. Thus adding this
- * early initcall function early_efi_map_fb() to map the whole EFI framebuffer.
- */
-static int __init efi_earlycon_remap_fb(void)
-{
- /* bail if there is no bootconsole or it has been disabled already */
- if (!earlycon_console || !(earlycon_console->flags & CON_ENABLED))
- return 0;
-
- efi_fb = memremap(fb_base, screen_info.lfb_size,
- fb_wb ? MEMREMAP_WB : MEMREMAP_WC);
-
- return efi_fb ? 0 : -ENOMEM;
-}
-early_initcall(efi_earlycon_remap_fb);
-
-static int __init efi_earlycon_unmap_fb(void)
-{
- /* unmap the bootconsole fb unless keep_bootcon has left it enabled */
- if (efi_fb && !(earlycon_console->flags & CON_ENABLED))
- memunmap(efi_fb);
- return 0;
-}
-late_initcall(efi_earlycon_unmap_fb);
-
-static __ref void *efi_earlycon_map(unsigned long start, unsigned long len)
-{
- pgprot_t fb_prot;
-
- if (efi_fb)
- return efi_fb + start;
-
- fb_prot = fb_wb ? PAGE_KERNEL : pgprot_writecombine(PAGE_KERNEL);
- return early_memremap_prot(fb_base + start, len, pgprot_val(fb_prot));
-}
-
-static __ref void efi_earlycon_unmap(void *addr, unsigned long len)
-{
- if (efi_fb)
- return;
-
- early_memunmap(addr, len);
-}
-
-static void efi_earlycon_clear_scanline(unsigned int y)
-{
- unsigned long *dst;
- u16 len;
-
- len = screen_info.lfb_linelength;
- dst = efi_earlycon_map(y*len, len);
- if (!dst)
- return;
-
- memset(dst, 0, len);
- efi_earlycon_unmap(dst, len);
-}
-
-static void efi_earlycon_scroll_up(void)
-{
- unsigned long *dst, *src;
- u16 len;
- u32 i, height;
-
- len = screen_info.lfb_linelength;
- height = screen_info.lfb_height;
-
- for (i = 0; i < height - font->height; i++) {
- dst = efi_earlycon_map(i*len, len);
- if (!dst)
- return;
-
- src = efi_earlycon_map((i + font->height) * len, len);
- if (!src) {
- efi_earlycon_unmap(dst, len);
- return;
- }
-
- memmove(dst, src, len);
-
- efi_earlycon_unmap(src, len);
- efi_earlycon_unmap(dst, len);
- }
-}
-
-static void efi_earlycon_write_char(u32 *dst, unsigned char c, unsigned int h)
-{
- const u32 color_black = 0x00000000;
- const u32 color_white = 0x00ffffff;
- const u8 *src;
- int m, n, bytes;
- u8 x;
-
- bytes = BITS_TO_BYTES(font->width);
- src = font->data + c * font->height * bytes + h * bytes;
-
- for (m = 0; m < font->width; m++) {
- n = m % 8;
- x = *(src + m / 8);
- if ((x >> (7 - n)) & 1)
- *dst = color_white;
- else
- *dst = color_black;
- dst++;
- }
-}
-
-static void
-efi_earlycon_write(struct console *con, const char *str, unsigned int num)
-{
- struct screen_info *si;
- unsigned int len;
- const char *s;
- void *dst;
-
- si = &screen_info;
- len = si->lfb_linelength;
-
- while (num) {
- unsigned int linemax;
- unsigned int h, count = 0;
-
- for (s = str; *s && *s != '\n'; s++) {
- if (count == num)
- break;
- count++;
- }
-
- linemax = (si->lfb_width - efi_x) / font->width;
- if (count > linemax)
- count = linemax;
-
- for (h = 0; h < font->height; h++) {
- unsigned int n, x;
-
- dst = efi_earlycon_map((efi_y + h) * len, len);
- if (!dst)
- return;
-
- s = str;
- n = count;
- x = efi_x;
-
- while (n-- > 0) {
- efi_earlycon_write_char(dst + x*4, *s, h);
- x += font->width;
- s++;
- }
-
- efi_earlycon_unmap(dst, len);
- }
-
- num -= count;
- efi_x += count * font->width;
- str += count;
-
- if (num > 0 && *s == '\n') {
- efi_x = 0;
- efi_y += font->height;
- str++;
- num--;
- }
-
- if (efi_x + font->width > si->lfb_width) {
- efi_x = 0;
- efi_y += font->height;
- }
-
- if (efi_y + font->height > si->lfb_height) {
- u32 i;
-
- efi_y -= font->height;
- efi_earlycon_scroll_up();
-
- for (i = 0; i < font->height; i++)
- efi_earlycon_clear_scanline(efi_y + i);
- }
- }
-}
-
-static int __init efi_earlycon_setup(struct earlycon_device *device,
- const char *opt)
-{
- struct screen_info *si;
- u16 xres, yres;
- u32 i;
-
- if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
- return -ENODEV;
-
- fb_base = screen_info.lfb_base;
- if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
- fb_base |= (u64)screen_info.ext_lfb_base << 32;
-
- fb_wb = opt && !strcmp(opt, "ram");
-
- si = &screen_info;
- xres = si->lfb_width;
- yres = si->lfb_height;
-
- /*
- * efi_earlycon_write_char() implicitly assumes a framebuffer with
- * 32 bits per pixel.
- */
- if (si->lfb_depth != 32)
- return -ENODEV;
-
- font = get_default_font(xres, yres, -1, -1);
- if (!font)
- return -ENODEV;
-
- efi_y = rounddown(yres, font->height) - font->height;
- for (i = 0; i < (yres - efi_y) / font->height; i++)
- efi_earlycon_scroll_up();
-
- device->con->write = efi_earlycon_write;
- earlycon_console = device->con;
- return 0;
-}
-EARLYCON_DECLARE(efifb, efi_earlycon_setup);
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 40c50fa2dd70c33a1549141b15e6cba721352d2d..8052507e058fce37f5a51058e58ae2eb10d9669a 100644
--- a/drivers/video/console/Kconfig
+++ b/drivers/video/console/Kconfig
@@ -69,6 +69,17 @@ config DUMMY_CONSOLE_ROWS
monitor.
Select 25 if you use a 640x480 resolution by default.

+config FB_EARLYCON
+ bool "Generic framebuffer early console"
+ depends on SERIAL_EARLYCON && !ARM && !IA64
+ select FONT_SUPPORT
+ select ARCH_USE_MEMREMAP_PROT
+ help
+ Say Y here if you want early console support for firmware established
+ linear framebuffer. Unless you are using EFI framebuffer, you need to
+ specify framebuffer geometry and address in device-tree or in kernel
+ command line.
+
config FRAMEBUFFER_CONSOLE
bool "Framebuffer Console support"
depends on FB && !UML
diff --git a/drivers/video/console/Makefile b/drivers/video/console/Makefile
index db07b784bd2ccdcbffde933926ed5cee2bbbc7d4..7818faee587fc9c40b429617cfa224c0ccbc557c 100644
--- a/drivers/video/console/Makefile
+++ b/drivers/video/console/Makefile
@@ -9,4 +9,5 @@ obj-$(CONFIG_STI_CONSOLE) += sticon.o sticore.o
obj-$(CONFIG_VGA_CONSOLE) += vgacon.o
obj-$(CONFIG_MDA_CONSOLE) += mdacon.o

+obj-$(CONFIG_FB_EARLYCON) += earlycon.o
obj-$(CONFIG_FB_STI) += sticore.o
diff --git a/drivers/video/console/earlycon.c b/drivers/video/console/earlycon.c
new file mode 100644
index 0000000000000000000000000000000000000000..54436587e3db90034652dcc144669dca91b863d5
--- /dev/null
+++ b/drivers/video/console/earlycon.c
@@ -0,0 +1,305 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2013 Intel Corporation; author Matt Fleming
+ * Copyright (C) 2022 Markuss Broks <markuss.broks@gmail.com>
+ */
+
+#include <asm/early_ioremap.h>
+#include <linux/console.h>
+#include <linux/efi.h>
+#include <linux/font.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/serial_core.h>
+#include <linux/screen_info.h>
+
+struct fb_earlycon {
+ u32 x, y, curr_x, curr_y, depth, stride;
+ size_t size;
+ phys_addr_t phys_base;
+ void __iomem *virt_base;
+};
+
+static const struct console *earlycon_console __initconst;
+static struct fb_earlycon info;
+static const struct font_desc *font;
+
+static int __init simplefb_earlycon_remap_fb(void)
+{
+ unsigned long mapping;
+ /* bail if there is no bootconsole or it has been disabled already */
+ if (!earlycon_console || !(earlycon_console->flags & CON_ENABLED))
+ return 0;
+
+ if (region_intersects(info.phys_base, info.size,
+ IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE) == REGION_INTERSECTS)
+ mapping = MEMREMAP_WB;
+ else
+ mapping = MEMREMAP_WC;
+
+ info.virt_base = memremap(info.phys_base, info.size, mapping);
+
+ return info.virt_base ? 0 : -ENOMEM;
+}
+early_initcall(simplefb_earlycon_remap_fb);
+
+static int __init simplefb_earlycon_unmap_fb(void)
+{
+ /* unmap the bootconsole fb unless keep_bootcon has left it enabled */
+ if (info.virt_base && !(earlycon_console->flags & CON_ENABLED))
+ memunmap(info.virt_base);
+ return 0;
+}
+late_initcall(simplefb_earlycon_unmap_fb);
+
+static __ref void *simplefb_earlycon_map(unsigned long start, unsigned long len)
+{
+ pgprot_t fb_prot;
+
+ if (info.virt_base)
+ return info.virt_base + start;
+
+ fb_prot = PAGE_KERNEL;
+ return early_memremap_prot(info.phys_base + start, len, pgprot_val(fb_prot));
+}
+
+static __ref void simplefb_earlycon_unmap(void *addr, unsigned long len)
+{
+ if (info.virt_base)
+ return;
+
+ early_memunmap(addr, len);
+}
+
+static void simplefb_earlycon_clear_scanline(unsigned int y)
+{
+ unsigned long *dst;
+ u16 len;
+
+ len = info.stride;
+ dst = simplefb_earlycon_map(y * len, len);
+ if (!dst)
+ return;
+
+ memset(dst, 0, len);
+ simplefb_earlycon_unmap(dst, len);
+}
+
+static void simplefb_earlycon_scroll_up(void)
+{
+ unsigned long *dst, *src;
+ u16 len;
+ u32 i, height;
+
+ len = info.stride;
+ height = info.y;
+
+ for (i = 0; i < height - font->height; i++) {
+ dst = simplefb_earlycon_map(i * len, len);
+ if (!dst)
+ return;
+
+ src = simplefb_earlycon_map((i + font->height) * len, len);
+ if (!src) {
+ simplefb_earlycon_unmap(dst, len);
+ return;
+ }
+
+ memmove(dst, src, len);
+
+ simplefb_earlycon_unmap(src, len);
+ simplefb_earlycon_unmap(dst, len);
+ }
+}
+
+static void simplefb_earlycon_write_char(u8 *dst, unsigned char c, unsigned int h)
+{
+ const u8 *src;
+ int m, n, bytes;
+ u8 x;
+
+ bytes = BITS_TO_BYTES(font->width);
+ src = font->data + c * font->height * bytes + h * bytes;
+
+ for (m = 0; m < font->width; m++) {
+ n = m % 8;
+ x = *(src + m / 8);
+ if ((x >> (7 - n)) & 1)
+ memset(dst, 0xff, (info.depth / 8));
+ else
+ memset(dst, 0, (info.depth / 8));
+ dst += (info.depth / 8);
+ }
+}
+
+static void
+simplefb_earlycon_write(struct console *con, const char *str, unsigned int num)
+{
+ unsigned int len;
+ const char *s;
+ void *dst;
+
+ len = info.stride;
+
+ while (num) {
+ unsigned int linemax;
+ unsigned int h, count = 0;
+
+ for (s = str; *s && *s != '\n'; s++) {
+ if (count == num)
+ break;
+ count++;
+ }
+
+ linemax = (info.x - info.curr_x) / font->width;
+ if (count > linemax)
+ count = linemax;
+
+ for (h = 0; h < font->height; h++) {
+ unsigned int n, x;
+
+ dst = simplefb_earlycon_map((info.curr_y + h) * len, len);
+ if (!dst)
+ return;
+
+ s = str;
+ n = count;
+ x = info.curr_x;
+
+ while (n-- > 0) {
+ simplefb_earlycon_write_char(dst + (x * 4), *s, h);
+ x += font->width;
+ s++;
+ }
+
+ simplefb_earlycon_unmap(dst, len);
+ }
+
+ num -= count;
+ info.curr_x += count * font->width;
+ str += count;
+
+ if (num > 0 && *s == '\n') {
+ info.curr_x = 0;
+ info.curr_y += font->height;
+ str++;
+ num--;
+ }
+
+ if (info.curr_x + font->width > info.x) {
+ info.curr_x = 0;
+ info.curr_y += font->height;
+ }
+
+ if (info.curr_y + font->height > info.y) {
+ u32 i;
+
+ info.curr_y -= font->height;
+ simplefb_earlycon_scroll_up();
+
+ for (i = 0; i < font->height; i++)
+ simplefb_earlycon_clear_scanline(info.curr_y + i);
+ }
+ }
+}
+
+static int __init simplefb_earlycon_setup_common(struct earlycon_device *device,
+ const char *opt)
+{
+ int i;
+
+ info.size = info.x * info.y * (info.depth / 8);
+
+ font = get_default_font(info.x, info.y, -1, -1);
+ if (!font)
+ return -ENODEV;
+
+ info.curr_y = rounddown(info.y, font->height) - font->height;
+ for (i = 0; i < (info.y - info.curr_y) / font->height; i++)
+ simplefb_earlycon_scroll_up();
+
+ device->con->write = simplefb_earlycon_write;
+ earlycon_console = device->con;
+ return 0;
+}
+
+static int __init simplefb_earlycon_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ struct uart_port *port = &device->port;
+ int ret;
+
+ if (!port->mapbase)
+ return -ENODEV;
+
+ info.phys_base = port->mapbase;
+
+ ret = sscanf(device->options, "%ux%ux%u", &info.x, &info.y, &info.depth);
+ if (ret != 3)
+ return -ENODEV;
+
+ info.stride = info.x * (info.depth / 8);
+
+ return simplefb_earlycon_setup_common(device, opt);
+}
+
+EARLYCON_DECLARE(simplefb, simplefb_earlycon_setup);
+
+#ifdef CONFIG_EFI_EARLYCON
+static int __init simplefb_earlycon_setup_efi(struct earlycon_device *device,
+ const char *opt)
+{
+ if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
+ return -ENODEV;
+
+ info.phys_base = screen_info.lfb_base;
+ if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+ info.phys_base |= (u64)screen_info.ext_lfb_base << 32;
+
+ info.x = screen_info.lfb_width;
+ info.y = screen_info.lfb_height;
+ info.depth = screen_info.lfb_depth;
+ info.stride = screen_info.lfb_linelength;
+
+ return simplefb_earlycon_setup_common(device, opt);
+}
+
+EARLYCON_DECLARE(efifb, simplefb_earlycon_setup_efi);
+#endif
+
+#ifdef CONFIG_OF_EARLY_FLATTREE
+static int __init simplefb_earlycon_setup_of(struct earlycon_device *device,
+ const char *opt)
+{
+ struct uart_port *port = &device->port;
+ const __be32 *val;
+
+ if (!port->mapbase)
+ return -ENODEV;
+
+ info.phys_base = port->mapbase;
+
+ val = of_get_flat_dt_prop(device->offset, "width", NULL);
+ if (!val)
+ return -ENODEV;
+ info.x = be32_to_cpu(*val);
+
+ val = of_get_flat_dt_prop(device->offset, "height", NULL);
+ if (!val)
+ return -ENODEV;
+ info.y = be32_to_cpu(*val);
+
+ val = of_get_flat_dt_prop(device->offset, "stride", NULL);
+ if (!val)
+ return -ENODEV;
+ info.stride = be32_to_cpu(*val);
+ info.depth = (info.stride / info.x) * 8;
+
+ return simplefb_earlycon_setup_common(device, opt);
+}
+
+OF_EARLYCON_DECLARE(simplefb, "simple-framebuffer", simplefb_earlycon_setup_of);
+#endif
--
2.37.0