path: root/drivers/video/fbdev/sstfb.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/drivers/video/sstfb.c -- voodoo graphics frame buffer
 *
 *     Copyright (c) 2000-2002 Ghozlane Toumi <gtoumi@laposte.net>
 *
 *     Created 15 Jan 2000 by Ghozlane Toumi
 *
 * Contributions (and many thanks) :
 *
 * 03/2001 James Simmons   <jsimmons@infradead.org>
 * 04/2001 Paul Mundt      <lethal@chaoticdreams.org>
 * 05/2001 Urs Ganse       <ursg@uni.de>
 *	(initial work on voodoo2 port, interlace)
 * 09/2002 Helge Deller    <deller@gmx.de>
 *	(enable driver on big-endian machines (hppa), ioctl fixes)
 * 12/2002 Helge Deller    <deller@gmx.de>
 *	(port driver to new frambuffer infrastructure)
 * 01/2003 Helge Deller    <deller@gmx.de>
 *	(initial work on fb hardware acceleration for voodoo2)
 * 08/2006 Alan Cox 	   <alan@redhat.com>
 *	Remove never finished and bogus 24/32bit support
 *	Clean up macro abuse
 *	Minor tidying for format.
 * 12/2006 Helge Deller    <deller@gmx.de>
 *	add /sys/class/graphics/fbX/vgapass sysfs-interface
 *	add module option "mode_option" to set initial screen mode
 *	use fbdev default videomode database
 *	remove debug functions from ioctl
 */

/*
 * The voodoo1 has the following memory mapped address space:
 * 0x000000 - 0x3fffff : registers              (4MB)
 * 0x400000 - 0x7fffff : linear frame buffer    (4MB)
 * 0x800000 - 0xffffff : texture memory         (8MB)
 */

/*
 * misc notes, TODOs, toASKs, and deep thoughts

-TODO: at one time or another test that the mode is acceptable by the monitor
-ASK: Can I choose different ordering for the color bitfields (rgba argb ...)
      which one should i use ? is there any preferred one ? It seems ARGB is
      the one ...
-TODO: in  set_var check the validity of timings (hsync vsync)...
-TODO: check and recheck the use of sst_wait_idle : we don't flush the fifo via
       a nop command. so it's ok as long as the commands we pass don't go
       through the fifo. warning: issuing a nop command seems to need pci_fifo
-FIXME: in case of failure in the init sequence, be sure we return to a safe
        state.
- FIXME: Use accelerator for 2D scroll
-FIXME: 4MB boards have banked memory (FbiInit2 bits 1 & 20)
 */

/*
 * debug info
 * SST_DEBUG : enable debugging
 * SST_DEBUG_REG : debug registers
 *   0 :  no debug
 *   1 : dac calls, [un]set_bits, FbiInit
 *   2 : insane debug level (log every register read/write)
 * SST_DEBUG_FUNC : functions
 *   0 : no debug
 *   1 : function call / debug ioctl
 *   2 : variables
 *   3 : flood . you don't want to do that. trust me.
 * SST_DEBUG_VAR : debug display/var structs
 *   0 : no debug
 *   1 : dumps display, fb_var
 *
 * sstfb specific ioctls:
 *   		toggle vga (0x46db) : toggle vga_pass_through
 */

#undef SST_DEBUG


/*
 * Includes
 */

#include <linux/aperture.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fb.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <asm/io.h>
#include <linux/uaccess.h>
#include <video/sstfb.h>


/* initialized by setup */

static bool vgapass;		/* enable VGA passthrough cable */
static int mem;			/* mem size in MB, 0 = autodetect */
static bool clipping = 1;	/* use clipping (slower, safer) */
static int gfxclk;		/* force FBI freq in Mhz . Dangerous */
static bool slowpci;		/* slow PCI settings */

/*
  Possible default video modes: 800x600@60, 640x480@75, 1024x768@76, 640x480@60
*/
#define DEFAULT_VIDEO_MODE "640x480@60"

static char *mode_option = DEFAULT_VIDEO_MODE;

enum {
	ID_VOODOO1 = 0,
	ID_VOODOO2 = 1,
};

#define IS_VOODOO2(par) ((par)->type == ID_VOODOO2)

static struct sst_spec voodoo_spec[] = {
 { .name = "Voodoo Graphics", .default_gfx_clock = 50000, .max_gfxclk = 60 },
 { .name = "Voodoo2",	      .default_gfx_clock = 75000, .max_gfxclk = 85 },
};


/*
 * debug functions
 */

#if (SST_DEBUG_REG > 0)
static void sst_dbg_print_read_reg(u32 reg, u32 val) {
	const char *regname;
	switch (reg) {
	case FBIINIT0:	regname = "FbiInit0"; break;
	case FBIINIT1:	regname = "FbiInit1"; break;
	case FBIINIT2:	regname = "FbiInit2"; break;
	case FBIINIT3:	regname = "FbiInit3"; break;
	case FBIINIT4:	regname = "FbiInit4"; break;
	case FBIINIT5:	regname = "FbiInit5"; break;
	case FBIINIT6:	regname = "FbiInit6"; break;
	default:	regname = NULL;       break;
	}
	if (regname == NULL)
		r_ddprintk("sst_read(%#x): %#x\n", reg, val);
	else
		r_dprintk(" sst_read(%s): %#x\n", regname, val);
}

static void sst_dbg_print_write_reg(u32 reg, u32 val) {
	const char *regname;
	switch (reg) {
	case FBIINIT0:	regname = "FbiInit0"; break;
	case FBIINIT1:	regname = "FbiInit1"; break;
	case FBIINIT2:	regname = "FbiInit2"; break;
	case FBIINIT3:	regname = "FbiInit3"; break;
	case FBIINIT4:	regname = "FbiInit4"; break;
	case FBIINIT5:	regname = "FbiInit5"; break;
	case FBIINIT6:	regname = "FbiInit6"; break;
	default:	regname = NULL;       break;
	}
	if (regname == NULL)
		r_ddprintk("sst_write(%#x, %#x)\n", reg, val);
	else
		r_dprintk(" sst_write(%s, %#x)\n", regname, val);
}
#else /*  (SST_DEBUG_REG > 0) */
#  define sst_dbg_print_read_reg(reg, val)	do {} while(0)
#  define sst_dbg_print_write_reg(reg, val)	do {} while(0)
#endif /*  (SST_DEBUG_REG > 0) */

/*
 * hardware access functions
 */

/* register access */
#define sst_read(reg)		__sst_read(par->mmio_vbase, reg)
#define sst_write(reg,val)	__sst_write(par->mmio_vbase, reg, val)
#define sst_set_bits(reg,val)	__sst_set_bits(par->mmio_vbase, reg, val)
#define sst_unset_bits(reg,val)	__sst_unset_bits(par->mmio_vbase, reg, val)
#define sst_dac_read(reg)	__sst_dac_read(par->mmio_vbase, reg)
#define sst_dac_write(reg,val)	__sst_dac_write(par->mmio_vbase, reg, val)
#define dac_i_read(reg)		__dac_i_read(par->mmio_vbase, reg)
#define dac_i_write(reg,val)	__dac_i_write(par->mmio_vbase, reg, val)

static inline u32 __sst_read(u8 __iomem *vbase, u32 reg)
{
	u32 ret = readl(vbase + reg);
	sst_dbg_print_read_reg(reg, ret);
	return ret;
}

static inline void __sst_write(u8 __iomem *vbase, u32 reg, u32 val)
{
	sst_dbg_print_write_reg(reg, val);
	writel(val, vbase + reg);
}

static inline void __sst_set_bits(u8 __iomem *vbase, u32 reg, u32 val)
{
	r_dprintk("sst_set_bits(%#x, %#x)\n", reg, val);
	__sst_write(vbase, reg, __sst_read(vbase, reg) | val);
}

static inline void __sst_unset_bits(u8 __iomem *vbase, u32 reg, u32 val)
{
	r_dprintk("sst_unset_bits(%#x, %#x)\n", reg, val);
	__sst_write(vbase, reg, __sst_read(vbase, reg) & ~val);
}

/*
 * wait for the fbi chip. ASK: what happens if the fbi is stuck ?
 *
 * the FBI is supposed to be ready if we receive 5 time
 * in a row a "idle" answer to our requests
 */

#define sst_wait_idle() __sst_wait_idle(par->mmio_vbase)

static int __sst_wait_idle(u8 __iomem *vbase)
{
	int count = 0;

	/* if (doFBINOP) __sst_write(vbase, NOPCMD, 0); */

	while(1) {
		if (__sst_read(vbase, STATUS) & STATUS_FBI_BUSY) {
			f_dddprintk("status: busy\n");
/* FIXME basically, this is a busy wait. maybe not that good. oh well;
 * this is a small loop after all.
 * Or maybe we should use mdelay() or udelay() here instead ? */
			count = 0;
		} else {
			count++;
			f_dddprintk("status: idle(%d)\n", count);
		}
		if (count >= 5) return 1;
/* XXX  do something to avoid han