[PATCH 04/18] video: bochs: Avoid using IO instructions to access VGA IO port

[Bin Meng]

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 <bm...@tinylab.org>
---

 drivers/video/bochs.c | 6 +++---
 drivers/video/bochs.h | 4 +---
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/video/bochs.c b/drivers/video/bochs.c
index 2d4526c714..5923ff81c6 100644
--- a/drivers/video/bochs.c
+++ b/drivers/video/bochs.c
@@ -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;
 
diff --git a/drivers/video/bochs.h b/drivers/video/bochs.h
index 71d3d60141..3facf690e5 100644
--- a/drivers/video/bochs.h
+++ b/drivers/video/bochs.h
@@ -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
-- 
2.34.1