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