[fb] Use system_map_mmio to map framebuffer

Update fb driver to use new j6_init_desc_framebuffer format with
physical address, and system_map_mmio to map the framebuffer into its
memory.

src/drivers/fb/main.cpp

@@ -4,6 +4,7 @@
 
 #include "j6/init.h"
 #include "j6/errors.h"
+#include "j6/flags.h"
 #include "j6/signals.h"
 #include "j6/syscalls.h"
 #include "j6/types.h"
@@ -18,6 +19,7 @@ extern "C" {
 }
 
 extern j6_handle_t __handle_sys;
+extern j6_handle_t __handle_self;
 
 struct entry
 {
@@ -45,15 +47,35 @@ main(int argc, const char **argv)
 		}
 	}
 
-	if (!fb || fb->addr == nullptr) {
+	if (!fb || fb->addr == 0) {
 		j6_system_log("fb driver didn't find a framebuffer, exiting");
 		return 1;
 	}
 
+	j6_handle_t fb_handle = j6_handle_invalid;
+	uint32_t flags =
+		j6_vm_flag_write |
+		j6_vm_flag_write_combine;
+	j6_status_t s = j6_system_map_mmio(__handle_sys, &fb_handle, fb->addr, fb->size, flags);
+	if (s != j6_status_ok) {
+		return s;
+	}
+
+	s = j6_vma_map(fb_handle, __handle_self, fb->addr);
+	if (s != j6_status_ok) {
+		return s;
+	}
+
 	const screen::pixel_order order = (fb->flags & 1) ?
 		screen::pixel_order::bgr8 : screen::pixel_order::rgb8;
 
-	screen scr(fb->addr, fb->horizontal, fb->vertical, order);
+	screen scr(
+		reinterpret_cast<void*>(fb->addr),
+		fb->horizontal,
+		fb->vertical,
+		fb->scanline,
+		order);
+
 	font fnt;
 
 	screen::pixel_t fg = scr.color(0xb0, 0xb0, 0xb0);

src/drivers/fb/screen.cpp

@@ -2,13 +2,14 @@
 #include <string.h>
 #include "screen.h"
 
-screen::screen(void *addr, unsigned hres, unsigned vres, pixel_order order) :
+screen::screen(volatile void *addr, unsigned hres, unsigned vres, unsigned scanline, pixel_order order) :
-	m_fb(static_cast<pixel_t *>(addr)),
+	m_fb(static_cast<volatile pixel_t *>(addr)),
 	m_order(order),
+	m_scanline(scanline),
 	m_resx(hres),
 	m_resy(vres)
 {
-	m_back = reinterpret_cast<pixel_t*>(malloc(hres*vres*sizeof(pixel_t)));
+	m_back = reinterpret_cast<pixel_t*>(malloc(scanline*vres*sizeof(pixel_t)));
 }
 
 screen::pixel_t
@@ -46,5 +47,7 @@ screen::draw_pixel(unsigned x, unsigned y, pixel_t color)
 void
 screen::update()
 {
-	memcpy(m_fb, m_back, m_resx*m_resy*sizeof(pixel_t));
+	const size_t len = m_scanline * m_resy * sizeof(pixel_t);
+	asm volatile ( "rep movsb" : :
+		"c"(len), "S"(m_back), "D"(m_fb) );
 }

src/drivers/fb/screen.h

@@ -9,7 +9,7 @@ public:
 
 	enum class pixel_order : uint8_t { bgr8, rgb8, };
 
-	screen(void *addr, unsigned hres, unsigned vres, pixel_order order);
+	screen(volatile void *addr, unsigned hres, unsigned vres, unsigned scanline, pixel_order order);
 
 	unsigned width() const { return m_resx; }
 	unsigned height() const { return m_resy; }
@@ -22,8 +22,10 @@ public:
 	void update();
 
 private:
-	pixel_t *m_fb, *m_back;
+	volatile pixel_t *m_fb;
+	pixel_t *m_back;
 	pixel_order m_order;
+	unsigned m_scanline;
 	unsigned m_resx, m_resy;
 
 	screen() = delete;