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video: bochs: Avoid using IO instructions to access VGA IO port

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At present the driver uses IO instructions to access the legacy
VGA IO ports, which unfortunately limits the driver to work only
on x86. It turns out the IO instruction is not necessary as Bochs
VGA card remaps the legacy VGA IO ports (0x3c0 -> 0x3df) to its
memory mapped register space from offset 0x400.

Update the driver to use MMIO access for VGA IO port.

Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>  # qemu-x86_64
This commit is contained in:
Bin Meng 2023-07-23 12:40:27 +08:00 committed by Anatolij Gustschin
parent caae795a1c
commit ffe1c8379e
2 changed files with 4 additions and 6 deletions
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6
drivers/video/bochs.c
View File

@ -27,9 +27,9 @@ static int bochs_read(void *mmio, int index)
return readw(mmio + MMIO_BASE + index * 2);
}
static void bochs_vga_write(uint8_t val)
static void bochs_vga_write(void *mmio, int index, uint8_t val)
{
outb(val, VGA_ATT_W);
writeb(val, mmio + VGA_BASE + index);
}
static int bochs_init_fb(struct udevice *dev)
@ -79,7 +79,7 @@ static int bochs_init_fb(struct udevice *dev)
bochs_write(mmio, INDEX_ENABLE, ENABLED | LFB_ENABLED);
/* disable blanking */
bochs_vga_write(VGA_AR_ENABLE_DISPLAY);
bochs_vga_write(mmio, VGA_ATT_W - VGA_INDEX, VGA_AR_ENABLE_DISPLAY);
plat->base = fb;

4
drivers/video/bochs.h
View File

@ -11,9 +11,6 @@
#define VGA_ATT_W 0x3c0
#define VGA_AR_ENABLE_DISPLAY 0x20
#define IOPORT_INDEX 0x01ce
#define IOPORT_DATA 0x01cf
enum {
INDEX_ID,
INDEX_XRES,
@ -34,6 +31,7 @@ enum {
#define LFB_ENABLED BIT(6)
#define NOCLEARMEM BIT(7)
#define VGA_BASE 0x400
#define MMIO_BASE 0x500
#endif