summaryrefslogtreecommitdiffstats
path: root/drivers/firmware/efi/earlycon.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--drivers/firmware/efi/earlycon.c246
1 files changed, 246 insertions, 0 deletions
diff --git a/drivers/firmware/efi/earlycon.c b/drivers/firmware/efi/earlycon.c
new file mode 100644
index 000000000..a52236e11
--- /dev/null
+++ b/drivers/firmware/efi/earlycon.c
@@ -0,0 +1,246 @@
+// 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);