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efi/earlycon: Fix early printk for wider fonts

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When I play with terminus fonts I noticed the efi early printk does
not work because the earlycon code assumes font width is 8.

Here add the code to adapt with larger fonts.  Tested with all kinds
of kernel built-in fonts on my laptop. Also tested with a local draft
patch for 14x28 !bold terminus font.

Signed-off-by: Dave Young <dyoung@redhat.com>
Link: https://lore.kernel.org/r/20200412024927.GA6884@dhcp-128-65.nay.redhat.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Dave Young 2020-04-12 10:49:27 +08:00 committed by Ard Biesheuvel
parent 081d515084
commit 8f592ada59
1 changed files with 8 additions and 6 deletions
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14
drivers/firmware/efi/earlycon.c
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@ -114,14 +114,16 @@ 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;
u8 s8;
int m;
int m, n, bytes;
u8 x;
src = font->data + c * font->height;
s8 = *(src + h);
bytes = BITS_TO_BYTES(font->width);
src = font->data + c * font->height * bytes + h * bytes;
for (m = 0; m < 8; m++) {
if ((s8 >> (7 - m)) & 1)
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;