Merge tag 'efi-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mfleming/efi into x86/efi

Pull EFI earlyprintk support from Matt Fleming:

 " * Add support for earlyprintk=efi which uses the EFI framebuffer. Very
     useful for debugging boot issues. "

Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 192 insertions, 0 deletions

diff --git a/arch/x86/platform/efi/Makefile b/arch/x86/platform/efi/Makefile
index 6db1cc4c7534..b7b0b35c1981 100644
--- a/arch/x86/platform/efi/Makefile
+++ b/arch/x86/platform/efi/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_EFI)               += efi.o efi_$(BITS).o efi_stub_$(BITS).o
 obj-$(CONFIG_ACPI_BGRT) += efi-bgrt.o
+obj-$(CONFIG_EARLY_PRINTK_EFI)  += early_printk.o
diff --git a/arch/x86/platform/efi/early_printk.c b/arch/x86/platform/efi/early_printk.c
new file mode 100644
index 000000000000..6599a0027b76
--- /dev/null
+++ b/arch/x86/platform/efi/early_printk.c
@@ -0,0 +1,191 @@
+/*
+ * Copyright (C) 2013 Intel Corporation; author Matt Fleming
+ *
+ *  This file is part of the Linux kernel, and is made available under
+ *  the terms of the GNU General Public License version 2.
+ */
+
+#include <linux/console.h>
+#include <linux/efi.h>
+#include <linux/font.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <asm/setup.h>
+
+static const struct font_desc *font;
+static u32 efi_x, efi_y;
+
+static __init void early_efi_clear_scanline(unsigned int y)
+{
+        unsigned long base, *dst;
+        u16 len;
+
+        base = boot_params.screen_info.lfb_base;
+        len = boot_params.screen_info.lfb_linelength;
+
+        dst = early_ioremap(base + y*len, len);
+        if (!dst)
+                return;
+
+        memset(dst, 0, len);
+        early_iounmap(dst, len);
+}
+
+static __init void early_efi_scroll_up(void)
+{
+        unsigned long base, *dst, *src;
+        u16 len;
+        u32 i, height;
+
+        base = boot_params.screen_info.lfb_base;
+        len = boot_params.screen_info.lfb_linelength;
+        height = boot_params.screen_info.lfb_height;
+
+        for (i = 0; i < height - font->height; i++) {
+                dst = early_ioremap(base + i*len, len);
+                if (!dst)
+                        return;
+
+                src = early_ioremap(base + (i + font->height) * len, len);
+                if (!src) {
+                        early_iounmap(dst, len);
+                        return;
+                }
+
+                memmove(dst, src, len);
+
+                early_iounmap(src, len);
+                early_iounmap(dst, len);
+        }
+}
+
+static void early_efi_write_char(u32 *dst, unsigned char c, unsigned int h)
+{
+        const u32 color_black = 0x00000000;
+        const u32 color_white = 0x00ffffff;
+        const u8 *src;
+        u8 s8;
+        int m;
+
+        src = font->data + c * font->height;
+        s8 = *(src + h);
+
+        for (m = 0; m < 8; m++) {
+                if ((s8 >> (7 - m)) & 1)
+                        *dst = color_white;
+                else
+                        *dst = color_black;
+                dst++;
+        }
+}
+
+static __init void
+early_efi_write(struct console *con, const char *str, unsigned int num)
+{
+        struct screen_info *si;
+        unsigned long base;
+        unsigned int len;
+        const char *s;
+        void *dst;
+
+        base = boot_params.screen_info.lfb_base;
+        si = &boot_params.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 = early_ioremap(base + (efi_y + h) * len, len);
+                        if (!dst)
+                                return;
+
+                        s = str;
+                        n = count;
+                        x = efi_x;
+
+                        while (n-- > 0) {
+                                early_efi_write_char(dst + x*4, *s, h);
+                                x += font->width;
+                                s++;
+                        }
+
+                        early_iounmap(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 >= si->lfb_width) {
+                        efi_x = 0;
+                        efi_y += font->height;
+                }
+
+                if (efi_y + font->height >= si->lfb_height) {
+                        u32 i;
+
+                        efi_y -= font->height;
+                        early_efi_scroll_up();
+
+                        for (i = 0; i < font->height; i++)
+                                early_efi_clear_scanline(efi_y + i);
+                }
+        }
+}
+
+static __init int early_efi_setup(struct console *con, char *options)
+{
+        struct screen_info *si;
+        u16 xres, yres;
+        u32 i;
+
+        si = &boot_params.screen_info;
+        xres = si->lfb_width;
+        yres = si->lfb_height;
+
+        /*
+         * early_efi_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++)
+                early_efi_scroll_up();
+
+        return 0;
+}
+
+struct console early_efi_console = {
+        .name =         "earlyefi",
+        .write =        early_efi_write,
+        .setup =        early_efi_setup,
+        .flags =        CON_PRINTBUFFER,
+        .index =        -1,
+};