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Commit e61d05dd authored by Stefan Kristiansson's avatar Stefan Kristiansson Committed by Tomi Valkeinen
Browse files

video: add OpenCores VGA/LCD framebuffer driver 

This adds support for the VGA/LCD core available from OpenCores:
http://opencores.org/project,vga_lcd



The driver have been tested together with both OpenRISC and
ARM (socfpga) processors.

Signed-off-by: default avatarStefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
parent db252957

drivers/video/Kconfig

+16 −0
Original line number Diff line number Diff line
@@ -980,6 +980,22 @@ config FB_PVR2 
	  (<file:drivers/video/pvr2fb.c>). Please see the file

	  <file:Documentation/fb/pvr2fb.txt>.



config FB_OPENCORES

	tristate "OpenCores VGA/LCD core 2.0 framebuffer support"

	depends on FB

	select FB_CFB_FILLRECT

	select FB_CFB_COPYAREA

	select FB_CFB_IMAGEBLIT

	help

	  This enables support for the OpenCores VGA/LCD core.



	  The OpenCores VGA/LCD core is typically used together with

	  softcore CPUs (e.g. OpenRISC or Microblaze) or hard processor

	  systems (e.g. Altera socfpga or Xilinx Zynq) on FPGAs.



	  The source code and specification for the core is available at

	  <http://opencores.org/project,vga_lcd>



config FB_S1D13XXX

	tristate "Epson S1D13XXX framebuffer support"

	depends on FB

drivers/video/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -150,6 +150,7 @@ obj-$(CONFIG_FB_NUC900) += nuc900fb.o 
obj-$(CONFIG_FB_JZ4740)		  += jz4740_fb.o

obj-$(CONFIG_FB_PUV3_UNIGFX)      += fb-puv3.o

obj-$(CONFIG_FB_HYPERV)		  += hyperv_fb.o

obj-$(CONFIG_FB_OPENCORES)	  += ocfb.o



# Platform or fallback drivers go here

obj-$(CONFIG_FB_UVESA)            += uvesafb.o

drivers/video/ocfb.c

0 → 100644
+440 −0
Original line number Diff line number Diff line 
/*

 * OpenCores VGA/LCD 2.0 core frame buffer driver

 *

 * Copyright (C) 2013 Stefan Kristiansson, stefan.kristiansson@saunalahti.fi

 *

 * This file is licensed under the terms of the GNU General Public License

 * version 2.  This program is licensed "as is" without any warranty of any

 * kind, whether express or implied.

 */



#include <linux/delay.h>

#include <linux/dma-mapping.h>

#include <linux/errno.h>

#include <linux/fb.h>

#include <linux/init.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/mm.h>

#include <linux/module.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/string.h>

#include <linux/slab.h>



/* OCFB register defines */

#define OCFB_CTRL	0x000

#define OCFB_STAT	0x004

#define OCFB_HTIM	0x008

#define OCFB_VTIM	0x00c

#define OCFB_HVLEN	0x010

#define OCFB_VBARA	0x014

#define OCFB_PALETTE	0x800



#define OCFB_CTRL_VEN	0x00000001 /* Video Enable */

#define OCFB_CTRL_HIE	0x00000002 /* HSync Interrupt Enable */

#define OCFB_CTRL_PC	0x00000800 /* 8-bit Pseudo Color Enable*/

#define OCFB_CTRL_CD8	0x00000000 /* Color Depth 8 */

#define OCFB_CTRL_CD16	0x00000200 /* Color Depth 16 */

#define OCFB_CTRL_CD24	0x00000400 /* Color Depth 24 */

#define OCFB_CTRL_CD32	0x00000600 /* Color Depth 32 */

#define OCFB_CTRL_VBL1	0x00000000 /* Burst Length 1 */

#define OCFB_CTRL_VBL2	0x00000080 /* Burst Length 2 */

#define OCFB_CTRL_VBL4	0x00000100 /* Burst Length 4 */

#define OCFB_CTRL_VBL8	0x00000180 /* Burst Length 8 */



#define PALETTE_SIZE	256



#define OCFB_NAME	"OC VGA/LCD"



static char *mode_option;



static const struct fb_videomode default_mode = {

	/* 640x480 @ 60 Hz, 31.5 kHz hsync */

	NULL, 60, 640, 480, 39721, 40, 24, 32, 11, 96, 2,

	0, FB_VMODE_NONINTERLACED

};



struct ocfb_dev {

	struct fb_info info;

	void __iomem *regs;

	/* flag indicating whether the regs are little endian accessed */

	int little_endian;

	/* Physical and virtual addresses of framebuffer */

	phys_addr_t fb_phys;

	void __iomem *fb_virt;

	u32 pseudo_palette[PALETTE_SIZE];

};



#ifndef MODULE

static int __init ocfb_setup(char *options)

{

	char *curr_opt;



	if (!options || !*options)

		return 0;



	while ((curr_opt = strsep(&options, ",")) != NULL) {

		if (!*curr_opt)

			continue;

		mode_option = curr_opt;

	}



	return 0;

}

#endif



static inline u32 ocfb_readreg(struct ocfb_dev *fbdev, loff_t offset)

{

	if (fbdev->little_endian)

		return ioread32(fbdev->regs + offset);

	else

		return ioread32be(fbdev->regs + offset);

}



static void ocfb_writereg(struct ocfb_dev *fbdev, loff_t offset, u32 data)

{

	if (fbdev->little_endian)

		iowrite32(data, fbdev->regs + offset);

	else

		iowrite32be(data, fbdev->regs + offset);

}



static int ocfb_setupfb(struct ocfb_dev *fbdev)

{

	unsigned long bpp_config;

	struct fb_var_screeninfo *var = &fbdev->info.var;

	struct device *dev = fbdev->info.device;

	u32 hlen;

	u32 vlen;



	/* Disable display */

	ocfb_writereg(fbdev, OCFB_CTRL, 0);



	/* Register framebuffer address */

	fbdev->little_endian = 0;

	ocfb_writereg(fbdev, OCFB_VBARA, fbdev->fb_phys);



	/* Detect endianess */

	if (ocfb_readreg(fbdev, OCFB_VBARA) != fbdev->fb_phys) {

		fbdev->little_endian = 1;

		ocfb_writereg(fbdev, OCFB_VBARA, fbdev->fb_phys);

	}



	/* Horizontal timings */

	ocfb_writereg(fbdev, OCFB_HTIM, (var->hsync_len - 1) << 24 |

		      (var->right_margin - 1) << 16 | (var->xres - 1));



	/* Vertical timings */

	ocfb_writereg(fbdev, OCFB_VTIM, (var->vsync_len - 1) << 24 |

		      (var->lower_margin - 1) << 16 | (var->yres - 1));



	/* Total length of frame */

	hlen = var->left_margin + var->right_margin + var->hsync_len +

		var->xres;



	vlen = var->upper_margin + var->lower_margin + var->vsync_len +

		var->yres;



	ocfb_writereg(fbdev, OCFB_HVLEN, (hlen - 1) << 16 | (vlen - 1));



	bpp_config = OCFB_CTRL_CD8;

	switch (var->bits_per_pixel) {

	case 8:

		if (!var->grayscale)

			bpp_config |= OCFB_CTRL_PC;  /* enable palette */

		break;



	case 16:

		bpp_config |= OCFB_CTRL_CD16;

		break;



	case 24:

		bpp_config |= OCFB_CTRL_CD24;

		break;



	case 32:

		bpp_config |= OCFB_CTRL_CD32;

		break;



	default:

		dev_err(dev, "no bpp specified\n");

		break;

	}



	/* maximum (8) VBL (video memory burst length) */

	bpp_config |= OCFB_CTRL_VBL8;



	/* Enable output */

	ocfb_writereg(fbdev, OCFB_CTRL, (OCFB_CTRL_VEN | bpp_config));



	return 0;

}



static int ocfb_setcolreg(unsigned regno, unsigned red, unsigned green,

			  unsigned blue, unsigned transp,

			  struct fb_info *info)

{

	struct ocfb_dev *fbdev = (struct ocfb_dev *)info->par;

	u32 color;



	if (regno >= info->cmap.len) {

		dev_err(info->device, "regno >= cmap.len\n");

		return 1;

	}



	if (info->var.grayscale) {

		/* grayscale = 0.30*R + 0.59*G + 0.11*B */

		red = green = blue = (red * 77 + green * 151 + blue * 28) >> 8;

	}



	red >>= (16 - info->var.red.length);

	green >>= (16 - info->var.green.length);

	blue >>= (16 - info->var.blue.length);

	transp >>= (16 - info->var.transp.length);



	if (info->var.bits_per_pixel == 8 && !info->var.grayscale) {

		regno <<= 2;

		color = (red << 16) | (green << 8) | blue;

		ocfb_writereg(fbdev, OCFB_PALETTE + regno, color);

	} else {

		((u32 *)(info->pseudo_palette))[regno] =

			(red << info->var.red.offset) |

			(green << info->var.green.offset) |

			(blue << info->var.blue.offset) |

			(transp << info->var.transp.offset);

	}



	return 0;

}



static int ocfb_init_fix(struct ocfb_dev *fbdev)

{

	struct fb_var_screeninfo *var = &fbdev->info.var;

	struct fb_fix_screeninfo *fix = &fbdev->info.fix;



	strcpy(fix->id, OCFB_NAME);



	fix->line_length = var->xres * var->bits_per_pixel/8;

	fix->smem_len = fix->line_length * var->yres;

	fix->type = FB_TYPE_PACKED_PIXELS;



	if (var->bits_per_pixel == 8 && !var->grayscale)

		fix->visual = FB_VISUAL_PSEUDOCOLOR;

	else

		fix->visual = FB_VISUAL_TRUECOLOR;



	return 0;

}



static int ocfb_init_var(struct ocfb_dev *fbdev)

{

	struct fb_var_screeninfo *var = &fbdev->info.var;



	var->accel_flags = FB_ACCEL_NONE;

	var->activate = FB_ACTIVATE_NOW;

	var->xres_virtual = var->xres;

	var->yres_virtual = var->yres;



	switch (var->bits_per_pixel) {

	case 8:

		var->transp.offset = 0;

		var->transp.length = 0;

		var->red.offset = 0;

		var->red.length = 8;

		var->green.offset = 0;

		var->green.length = 8;

		var->blue.offset = 0;

		var->blue.length = 8;

		break;



	case 16:

		var->transp.offset = 0;

		var->transp.length = 0;

		var->red.offset = 11;

		var->red.length = 5;

		var->green.offset = 5;

		var->green.length = 6;

		var->blue.offset = 0;

		var->blue.length  = 5;

		break;



	case 24:

		var->transp.offset = 0;

		var->transp.length = 0;

		var->red.offset = 16;

		var->red.length = 8;

		var->green.offset = 8;

		var->green.length = 8;

		var->blue.offset = 0;

		var->blue.length = 8;

		break;



	case 32:

		var->transp.offset = 24;

		var->transp.length = 8;

		var->red.offset = 16;

		var->red.length = 8;

		var->green.offset = 8;

		var->green.length = 8;

		var->blue.offset = 0;

		var->blue.length = 8;

		break;

	}



	return 0;

}



static struct fb_ops ocfb_ops = {

	.owner		= THIS_MODULE,

	.fb_setcolreg	= ocfb_setcolreg,

	.fb_fillrect	= cfb_fillrect,

	.fb_copyarea	= cfb_copyarea,

	.fb_imageblit	= cfb_imageblit,

};



static int ocfb_probe(struct platform_device *pdev)

{

	int ret = 0;

	struct ocfb_dev *fbdev;

	struct resource *res;

	int fbsize;



	fbdev = devm_kzalloc(&pdev->dev, sizeof(*fbdev), GFP_KERNEL);

	if (!fbdev)

		return -ENOMEM;



	platform_set_drvdata(pdev, fbdev);



	fbdev->info.fbops = &ocfb_ops;

	fbdev->info.device = &pdev->dev;

	fbdev->info.par = fbdev;



	/* Video mode setup */

	if (!fb_find_mode(&fbdev->info.var, &fbdev->info, mode_option,

			  NULL, 0, &default_mode, 16)) {

		dev_err(&pdev->dev, "No valid video modes found\n");

		return -EINVAL;

	}

	ocfb_init_var(fbdev);

	ocfb_init_fix(fbdev);



	/* Request I/O resource */

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!res) {

		dev_err(&pdev->dev, "I/O resource request failed\n");

		return -ENXIO;

	}

	res->flags &= ~IORESOURCE_CACHEABLE;

	fbdev->regs = devm_ioremap_resource(&pdev->dev, res);

	if (IS_ERR(fbdev->regs))

		return PTR_ERR(fbdev->regs);



	/* Allocate framebuffer memory */

	fbsize = fbdev->info.fix.smem_len;

	fbdev->fb_virt = dma_alloc_coherent(&pdev->dev, PAGE_ALIGN(fbsize),

					    &fbdev->fb_phys, GFP_KERNEL);

	if (!fbdev->fb_virt) {

		dev_err(&pdev->dev,

			"Frame buffer memory allocation failed\n");

		return -ENOMEM;

	}

	fbdev->info.fix.smem_start = fbdev->fb_phys;

	fbdev->info.screen_base = fbdev->fb_virt;

	fbdev->info.pseudo_palette = fbdev->pseudo_palette;



	/* Clear framebuffer */

	memset_io(fbdev->fb_virt, 0, fbsize);



	/* Setup and enable the framebuffer */

	ocfb_setupfb(fbdev);



	if (fbdev->little_endian)

		fbdev->info.flags |= FBINFO_FOREIGN_ENDIAN;



	/* Allocate color map */

	ret = fb_alloc_cmap(&fbdev->info.cmap, PALETTE_SIZE, 0);

	if (ret) {

		dev_err(&pdev->dev, "Color map allocation failed\n");

		goto err_dma_free;

	}



	/* Register framebuffer */

	ret = register_framebuffer(&fbdev->info);

	if (ret) {

		dev_err(&pdev->dev, "Framebuffer registration failed\n");

		goto err_dealloc_cmap;

	}



	return 0;



err_dealloc_cmap:

	fb_dealloc_cmap(&fbdev->info.cmap);



err_dma_free:

	dma_free_coherent(&pdev->dev, PAGE_ALIGN(fbsize), fbdev->fb_virt,

			  fbdev->fb_phys);



	return ret;

}



static int ocfb_remove(struct platform_device *pdev)

{

	struct ocfb_dev *fbdev = platform_get_drvdata(pdev);



	unregister_framebuffer(&fbdev->info);

	fb_dealloc_cmap(&fbdev->info.cmap);

	dma_free_coherent(&pdev->dev, PAGE_ALIGN(fbdev->info.fix.smem_len),

			  fbdev->fb_virt, fbdev->fb_phys);



	/* Disable display */

	ocfb_writereg(fbdev, OCFB_CTRL, 0);



	platform_set_drvdata(pdev, NULL);



	return 0;

}



static struct of_device_id ocfb_match[] = {

	{ .compatible = "opencores,ocfb", },

	{},

};

MODULE_DEVICE_TABLE(of, ocfb_match);



static struct platform_driver ocfb_driver = {

	.probe  = ocfb_probe,

	.remove	= ocfb_remove,

	.driver = {

		.name = "ocfb_fb",

		.of_match_table = ocfb_match,

	}

};



/*

 * Init and exit routines

 */

static int __init ocfb_init(void)

{

#ifndef MODULE

	char *option = NULL;



	if (fb_get_options("ocfb", &option))

		return -ENODEV;

	ocfb_setup(option);

#endif

	return platform_driver_register(&ocfb_driver);

}



static void __exit ocfb_exit(void)

{

	platform_driver_unregister(&ocfb_driver);

}



module_init(ocfb_init);

module_exit(ocfb_exit);



MODULE_AUTHOR("Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>");

MODULE_DESCRIPTION("OpenCores VGA/LCD 2.0 frame buffer driver");

MODULE_LICENSE("GPL v2");

module_param(mode_option, charp, 0);

MODULE_PARM_DESC(mode_option, "Video mode ('<xres>x<yres>[-<bpp>][@refresh]')");