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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v2 3/8] xen: introduce a generic framebuffer driver
On Mon, 10 Dec 2012, Jan Beulich wrote:
> >>> On 07.12.12 at 19:02, Stefano Stabellini
> >>> <stefano.stabellini@xxxxxxxxxxxxx>
> wrote:
> > Abstract away from vesa.c the funcions to handle a linear framebuffer
> > and print characters to it.
> > The corresponding functions are going to be removed from vesa.c in the
> > next patch.
> >
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > ---
> > xen/drivers/video/Makefile | 1 +
> > xen/drivers/video/fb.c | 209
> > ++++++++++++++++++++++++++++++++++++++++++++
> > xen/drivers/video/fb.h | 49 ++++++++++
> > 3 files changed, 259 insertions(+), 0 deletions(-)
> > create mode 100644 xen/drivers/video/fb.c
> > create mode 100644 xen/drivers/video/fb.h
> >
> > diff --git a/xen/drivers/video/Makefile b/xen/drivers/video/Makefile
> > index 2993c39..3b3eb43 100644
> > --- a/xen/drivers/video/Makefile
> > +++ b/xen/drivers/video/Makefile
> > @@ -2,4 +2,5 @@ obj-$(HAS_VGA) := vga.o
> > obj-$(HAS_VIDEO) += font_8x14.o
> > obj-$(HAS_VIDEO) += font_8x16.o
> > obj-$(HAS_VIDEO) += font_8x8.o
> > +obj-$(HAS_VIDEO) += fb.o
> > obj-$(HAS_VGA) += vesa.o
> > diff --git a/xen/drivers/video/fb.c b/xen/drivers/video/fb.c
> > new file mode 100644
> > index 0000000..282f97e
> > --- /dev/null
> > +++ b/xen/drivers/video/fb.c
> > @@ -0,0 +1,209 @@
> > +/**************************************************************************
> > ****
> > + * fb.c
> > + *
> > + * linear frame buffer handling.
> > + */
> > +
> > +#include <xen/config.h>
> > +#include <xen/kernel.h>
> > +#include <xen/lib.h>
> > +#include <xen/errno.h>
> > +#include "fb.h"
> > +#include "font.h"
> > +
> > +#define MAX_XRES 1900
> > +#define MAX_YRES 1200
> > +#define MAX_BPP 4
> > +#define MAX_FONT_W 8
> > +#define MAX_FONT_H 16
> > +static __initdata unsigned int line_len[MAX_XRES / MAX_FONT_W];
> > +static __initdata unsigned char lbuf[MAX_XRES * MAX_BPP];
> > +static __initdata unsigned char text_buf[(MAX_XRES / MAX_FONT_W) * \
> > + (MAX_YRES / MAX_FONT_H)];
> > +
> > +struct fb_status {
> > + struct fb_prop fbp;
> > +
> > + unsigned char *lbuf, *text_buf;
> > + unsigned int *line_len;
> > + unsigned int xpos, ypos;
> > +};
> > +static struct fb_status fb;
> > +
> > +static void fb_show_line(
> > + const unsigned char *text_line,
> > + unsigned char *video_line,
> > + unsigned int nr_chars,
> > + unsigned int nr_cells)
> > +{
> > + unsigned int i, j, b, bpp, pixel;
> > +
> > + bpp = (fb.fbp.bits_per_pixel + 7) >> 3;
> > +
> > + for ( i = 0; i < fb.fbp.font->height; i++ )
> > + {
> > + unsigned char *ptr = fb.lbuf;
> > +
> > + for ( j = 0; j < nr_chars; j++ )
> > + {
> > + const unsigned char *bits = fb.fbp.font->data;
> > + bits += ((text_line[j] * fb.fbp.font->height + i) *
> > + ((fb.fbp.font->width + 7) >> 3));
> > + for ( b = fb.fbp.font->width; b--; )
> > + {
> > + pixel = (*bits & (1u<<b)) ? fb.fbp.pixel_on : 0;
> > + memcpy(ptr, &pixel, bpp);
> > + ptr += bpp;
> > + }
> > + }
> > +
> > + memset(ptr, 0, (fb.fbp.width - nr_chars * fb.fbp.font->width) *
> > bpp);
> > + memcpy(video_line, fb.lbuf, nr_cells * fb.fbp.font->width * bpp);
> > + video_line += fb.fbp.bytes_per_line;
> > + }
> > +}
> > +
> > +/* Fast mode which redraws all modified parts of a 2D text buffer. */
> > +void fb_redraw_puts(const char *s)
> > +{
> > + unsigned int i, min_redraw_y = fb.ypos;
> > + char c;
> > +
> > + /* Paste characters into text buffer. */
> > + while ( (c = *s++) != '\0' )
> > + {
> > + if ( (c == '\n') || (fb.xpos >= fb.fbp.text_columns) )
> > + {
> > + if ( ++fb.ypos >= fb.fbp.text_rows )
> > + {
> > + min_redraw_y = 0;
> > + fb.ypos = fb.fbp.text_rows - 1;
> > + memmove(fb.text_buf, fb.text_buf + fb.fbp.text_columns,
> > + fb.ypos * fb.fbp.text_columns);
> > + memset(fb.text_buf + fb.ypos * fb.fbp.text_columns, 0,
> > fb.xpos);
> > + }
> > + fb.xpos = 0;
> > + }
> > +
> > + if ( c != '\n' )
> > + fb.text_buf[fb.xpos++ + fb.ypos * fb.fbp.text_columns] = c;
> > + }
> > +
> > + /* Render modified section of text buffer to VESA linear framebuffer.
> > */
> > + for ( i = min_redraw_y; i <= fb.ypos; i++ )
> > + {
> > + const unsigned char *line = fb.text_buf + i * fb.fbp.text_columns;
> > + unsigned int width;
> > +
> > + for ( width = fb.fbp.text_columns; width; --width )
> > + if ( line[width - 1] )
> > + break;
> > + fb_show_line(line,
> > + fb.fbp.lfb + i * fb.fbp.font->height *
> > fb.fbp.bytes_per_line,
> > + width, max(fb.line_len[i], width));
> > + fb.line_len[i] = width;
> > + }
> > +
> > + fb.fbp.flush();
> > +}
> > +
> > +/* Slower line-based scroll mode which interacts better with dom0. */
> > +void fb_scroll_puts(const char *s)
> > +{
> > + unsigned int i;
> > + char c;
> > +
> > + while ( (c = *s++) != '\0' )
> > + {
> > + if ( (c == '\n') || (fb.xpos >= fb.fbp.text_columns) )
> > + {
> > + unsigned int bytes = (fb.fbp.width *
> > + ((fb.fbp.bits_per_pixel + 7) >> 3));
> > + unsigned char *src = fb.fbp.lfb + fb.fbp.font->height *
> > fb.fbp.bytes_per_line;
> > + unsigned char *dst = fb.fbp.lfb;
> > +
> > + /* New line: scroll all previous rows up one line. */
> > + for ( i = fb.fbp.font->height; i < fb.fbp.height; i++ )
> > + {
> > + memcpy(dst, src, bytes);
> > + src += fb.fbp.bytes_per_line;
> > + dst += fb.fbp.bytes_per_line;
> > + }
> > +
> > + /* Render new line. */
> > + fb_show_line(
> > + fb.text_buf,
> > + fb.fbp.lfb + (fb.fbp.text_rows-1) * fb.fbp.font->height *
> > fb.fbp.bytes_per_line,
> > + fb.xpos, fb.fbp.text_columns);
> > +
> > + fb.xpos = 0;
> > + }
> > +
> > + if ( c != '\n' )
> > + fb.text_buf[fb.xpos++] = c;
> > + }
> > +
> > + fb.fbp.flush();
> > +}
> > +
> > +void fb_cr(void)
> > +{
> > + fb.xpos = 0;
> > +}
> > +
> > +int __init fb_init(struct fb_prop fbp)
> > +{
> > + if ( fbp.width > MAX_XRES || fbp.height > MAX_YRES )
> > + {
> > + printk("Couldn't initialize a %xx%x framebuffer early.\n",
> > + fbp.width, fbp.height);
> > + return -EINVAL;
> > + }
> > +
> > + fb.fbp = fbp;
> > + fb.lbuf = lbuf;
> > + fb.text_buf = text_buf;
> > + fb.line_len = line_len;
> > + return 0;
> > +}
> > +
> > +int __init fb_alloc(void)
> > +{
> > + fb.lbuf = NULL;
> > + fb.text_buf = NULL;
> > + fb.line_len = NULL;
> > +
> > + fb.lbuf = xmalloc_bytes(fb.fbp.bytes_per_line);
> > + if ( !fb.lbuf )
> > + goto fail;
> > +
> > + fb.text_buf = xzalloc_bytes(fb.fbp.text_columns * fb.fbp.text_rows);
> > + if ( !fb.text_buf )
> > + goto fail;
> > +
> > + fb.line_len = xzalloc_array(unsigned int, fb.fbp.text_columns);
> > + if ( !fb.line_len )
> > + goto fail;
> > +
> > + memcpy(fb.lbuf, lbuf, fb.fbp.bytes_per_line);
> > + memcpy(fb.text_buf, text_buf, fb.fbp.text_columns * fb.fbp.text_rows);
> > + memcpy(fb.line_len, line_len, fb.fbp.text_columns);
> > +
> > + return 0;
> > +
> > +fail:
> > + printk(XENLOG_ERR "Couldn't allocate enough memory to drive "
> > + "the framebuffer\n");
> > + xfree(fb.lbuf);
> > + xfree(fb.text_buf);
> > + xfree(fb.line_len);
> > +
> > + return -ENOMEM;
> > +}
> > +
> > +void fb_free(void)
> > +{
> > + xfree(fb.lbuf);
> > + xfree(fb.text_buf);
> > + xfree(fb.line_len);
> > +}
> > diff --git a/xen/drivers/video/fb.h b/xen/drivers/video/fb.h
> > new file mode 100644
> > index 0000000..558d058
> > --- /dev/null
> > +++ b/xen/drivers/video/fb.h
> > @@ -0,0 +1,49 @@
> > +/*
> > + * xen/drivers/video/fb.h
> > + *
> > + * Cross-platform framebuffer library
> > + *
> > + * Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > + * Copyright (c) 2012 Citrix Systems.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +#ifndef _XEN_FB_H
> > +#define _XEN_FB_H
> > +
> > +#include <xen/init.h>
> > +
> > +struct fb_prop {
> > + const struct font_desc *font;
> > + unsigned char *lfb;
> > + unsigned int pixel_on;
> > + uint16_t width, height;
> > + uint16_t bytes_per_line;
> > + uint16_t bits_per_pixel;
> > + void (*flush)(void);
> > +
> > + unsigned int text_columns;
> > + unsigned int text_rows;
> > +};
> > +
> > +void fb_redraw_puts(const char *s);
> > +void fb_scroll_puts(const char *s);
> > +void fb_cr(void);
>
> Please make this fb_create() or alike - "cr" alone could well be
> mistaken as "carriage return".
Actually it is supposed to be "cr": it is used by vesa_endboot to reset
the cursor to column 0.
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