linux/drivers/gpu/drm/radeon/atom.c

/*
 * Copyright 2008 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Author: Stanislaw Skowronek
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <asm/unaligned.h>

#define ATOM_DEBUG

#include "atom.h"
#include "atom-names.h"
#include "atom-bits.h"

#define ATOM_COND_ABOVE		0
#define ATOM_COND_ABOVEOREQUAL	1
#define ATOM_COND_ALWAYS	2
#define ATOM_COND_BELOW		3
#define ATOM_COND_BELOWOREQUAL	4
#define ATOM_COND_EQUAL		5
#define ATOM_COND_NOTEQUAL	6

#define ATOM_PORT_ATI	0
#define ATOM_PORT_PCI	1
#define ATOM_PORT_SYSIO	2

#define ATOM_UNIT_MICROSEC	0
#define ATOM_UNIT_MILLISEC	1

#define PLL_INDEX	2
#define PLL_DATA	3

typedef struct {
	struct atom_context *ctx;
	uint32_t *ps, *ws;
	int ps_shift;
	uint16_t start;
	unsigned last_jump;
	unsigned long last_jump_jiffies;
	bool abort;
} atom_exec_context;

int atom_debug = 0;
static int atom_execute_table_locked(struct atom_context *ctx, int index, uint32_t * params);
int atom_execute_table(struct atom_context *ctx, int index, uint32_t * params);

static uint32_t atom_arg_mask[8] =
    { 0xFFFFFFFF, 0xFFFF, 0xFFFF00, 0xFFFF0000, 0xFF, 0xFF00, 0xFF0000,
0xFF000000 };
static int atom_arg_shift[8] = { 0, 0, 8, 16, 0, 8, 16, 24 };

static int atom_dst_to_src[8][4] = {
	/* translate destination alignment field to the source alignment encoding */
	{0, 0, 0, 0},
	{1, 2, 3, 0},
	{1, 2, 3, 0},
	{1, 2, 3, 0},
	{4, 5, 6, 7},
	{4, 5, 6, 7},
	{4, 5, 6, 7},
	{4, 5, 6, 7},
};
static int atom_def_dst[8] = { 0, 0, 1, 2, 0, 1, 2, 3 };

static int debug_depth = 0;
#ifdef ATOM_DEBUG
static void debug_print_spaces(int n)
{
	while (n--)
		printk("   ");
}

#define DEBUG(...) do if (atom_debug) { printk(KERN_DEBUG __VA_ARGS__); } while (0)
#define SDEBUG(...) do if (atom_debug) { printk(KERN_DEBUG); debug_print_spaces(debug_depth); printk(__VA_ARGS__); } while (0)
#else
#define DEBUG(...) do { } while (0)
#define SDEBUG(...) do { } while (0)
#endif

static uint32_t atom_iio_execute(struct atom_context *ctx, int base,
				 uint32_t index, uint32_t data)
{
	uint32_t temp = 0xCDCDCDCD;
	while (1)
		switch (CU8(base)) {
		case ATOM_IIO_NOP:
			base++;
			break;
		case ATOM_IIO_READ:
			temp = ctx->card->reg_read(ctx->card, CU16(base + 1));
			base += 3;
			break;
		case ATOM_IIO_WRITE:
			(void)ctx->card->reg_read(ctx->card, CU16(base + 1));
			ctx->card->reg_write(ctx->card, CU16(base + 1), temp);
			base += 3;
			break;
		case ATOM_IIO_CLEAR:
			temp &=
			    ~((0xFFFFFFFF >> (32 - CU8(base + 1))) <<
			      CU8(base + 2));
			base += 3;
			break;
		case ATOM_IIO_SET:
			temp |=
			    (0xFFFFFFFF >> (32 - CU8(base + 1))) << CU8(base +
									2);
			base += 3;
			break;
		case ATOM_IIO_MOVE_INDEX:
			temp &=
			    ~((0xFFFFFFFF >> (32 - CU8(base + 1))) <<
			      CU8(base + 2));
			temp |=
			    ((index >> CU8(base + 2)) &
			     (0xFFFFFFFF >> (32 - CU8(base + 1)))) << CU8(base +
									  3);
			base += 4;
			break;
		case ATOM_IIO_MOVE_DATA:
			temp &=
			    ~((0xFFFFFFFF >> (32 - CU8(base + 1))) <<
			      CU8(base + 2));
			temp |=
			    ((data >> CU8(base + 2)) &
			     (0xFFFFFFFF >> (32 - CU8(base + 1)))) << CU8(base +
									  3);
			base += 4;
			break;
		case ATOM_IIO_MOVE_ATTR:
			temp &=
			    ~((0xFFFFFFFF >> (32 - CU8(base + 1))) <<
			      CU8(base + 2));
			temp |=
			    ((ctx->
			      io_attr >> CU8(base + 2)) & (0xFFFFFFFF >> (32 -
									  CU8
									  (base
									   +
									   1))))
			    << CU8(base + 3);
			base += 4;
			break;
		case ATOM_IIO_END:
			return temp;
		default:
			printk(KERN_INFO "Unknown IIO opcode.\n");
			return 0;
		}
}

static uint32_t atom_get_src_int(atom_exec_context *ctx, uint8_t attr,
				 int *ptr, uint32_t *saved, int print)
{
	uint32_t idx, val = 0xCDCDCDCD, align, arg;
	struct atom_context *gctx = ctx->ctx;
	arg = attr & 7;
	align = (attr >> 3) & 7;
	switch (arg) {
	case ATOM_ARG_REG:
		idx = U16(*ptr);
		(*ptr) += 2;
		if (print)
			DEBUG("REG[0x%04X]", idx);
		idx += gctx->reg_block;
		switch (gctx->io_mode) {
		case ATOM_IO_MM:
			val = gctx->card->reg_read(gctx->card, idx);
			break;
		case ATOM_IO_PCI:
			printk(KERN_INFO
			       "PCI registers are not implemented.\n");
			return 0;
		case ATOM_IO_SYSIO:
			printk(KERN_INFO
			       "SYSIO registers are not implemented.\n");
			return 0;
		default:
			if (!(gctx->io_mode & 0x80)) {
				printk(KERN_INFO "Bad IO mode.\n");
				return 0;
			}
			if (!gctx->iio[gctx->io_mode & 0x7F]) {
				printk(KERN_INFO
				       "Undefined indirect IO read method %d.\n",
				       gctx->io_mode & 0x7F);
				return 0;
			}
			val =
			    atom_iio_execute(gctx,
					     gctx->iio[gctx->io_mode & 0x7F],
					     idx, 0);
		}
		break;
	case ATOM_ARG_PS:
		idx = U8(*ptr);
		(*ptr)++;
		/* get_unaligned_le32 avoids unaligned accesses from atombios
		 * tables, noticed on a DEC Alpha. */
		val = get_unaligned_le32((u32 *)&ctx->ps[idx]);
		if (print)
			DEBUG("PS[0x%02X,0x%04X]", idx, val);
		break;
	case ATOM_ARG_WS:
		idx = U8(*ptr);
		(*ptr)++;
		if (print)
			DEBUG("WS[0x%02X]", idx);
		switch (idx) {
		case ATOM_WS_QUOTIENT:
			val = gctx->divmul[0];
			break;
		case ATOM_WS_REMAINDER:
			val = gctx->divmul[1];
			break;
		case ATOM_WS_DATAPTR:
			val = gctx->data_block;
			break;
		case ATOM_WS_SHIFT:
			val = gctx->shift;
			break;
		case ATOM_WS_OR_MASK:
			val = 1 << gctx->shift;
			break;
		case ATOM_WS_AND_MASK:
			val = ~(1 << gctx->shift);
			break;
		case ATOM_WS_FB_WINDOW:
			val = gctx->fb_base;
			break;
		case ATOM_WS_ATTRIBUTES:
			val = gctx->io_attr;
			break;
		case ATOM_WS_REGPTR:
			val = gctx->reg_block;
			break;
		default:
			val = ctx->ws[idx];
		}
		break;
	case ATOM_ARG_ID:
		idx = U16(*ptr);
		(*ptr) += 2;
		if (print) {
			if (gctx->data_block)
				DEBUG("ID[0x%04X+%04X]", idx, gctx->data_block);
			else
				DEBUG("ID[0x%04X]", idx);
		}
		val = U32(idx + gctx->data_block);
		break;
	case ATOM_ARG_FB:
		idx = U8(*ptr);
		(*ptr)++;
		val = gctx->scratch[((gctx->fb_base + idx) / 4)];
		if (print)
			DEBUG("FB[0x%02X]", idx);
		break;
	case ATOM_ARG_IMM:
		switch (align) {
		case ATOM_SRC_DWORD:
			val = U32(*ptr);
			(*ptr) += 4;
			if (print)
				DEBUG("IMM 0x%08X\n", val);
			return val;
		case ATOM_SRC_WORD0:
		case ATOM_SRC_WORD8:
		case ATOM_SRC_WORD16:
			val = U16(*ptr);
			(*ptr) += 2;
			if (print)
				DEBUG("IMM 0x%04X\n", val);
			return val;
		case ATOM_SRC_BYTE0:
		case ATOM_SRC_BYTE8:
		case ATOM_SRC_BYTE16:
		case ATOM_SRC_BYTE24:
			val = U8(*ptr);
			(*ptr)++;
			if (print)
				DEBUG("IMM 0x%02X\n", val);
			return val;
		}
		return 0;
	case ATOM_ARG_PLL:
		idx = U8(*ptr);
		(*ptr)++;
		if (print)
			DEBUG("PLL[0x%02X]", idx);
		val = gctx->card->pll_read(gctx->card, idx);
		break;
	case ATOM_ARG_MC:
		idx = U8(*ptr);
		(*ptr)++;
		if (print)
			DEBUG("MC[0x%02X]", idx);
		val = gctx->card->mc_read(gctx->card, idx);
		break;
	}
	if (saved)
		*saved = val;
	val &= atom_arg_mask[align];
	val >>= atom_arg_shift[align];
	if (print)
		switch (align) {
		case ATOM_SRC_DWORD:
			DEBUG(".[31:0] -> 0x%08X\n", val);
			break;
		case ATOM_SRC_WORD0:
			DEBUG(".[15:0] -> 0x%04X\n", val);
			break;
		case ATOM_SRC_WORD8:
			DEBUG(".[23:8] -> 0x%04X\n", val);
			break;
		case ATOM_SRC_WORD16:
			DEBUG(".[31:16] -> 0x%04X\n", val);
			break;
		case ATOM_SRC_BYTE0:
			DEBUG(".[7:0] -> 0x%02X\n", val);
			break;
		case ATOM_SRC_BYTE8:
			DEBUG(".[15:8] -> 0x%02X\n", val);
			break;
		case ATOM_SRC_BYTE16:
			DEBUG(".[23:16] -> 0x%02X\n", val);
			break;
		case ATOM_SRC_BYTE24:
			DEBUG(".[31:24] -> 0x%02X\n", val);
			break;
		}
	return val;
}

static void atom_skip_src_int(atom_exec_context *ctx, uint8_t attr, int *ptr)
{
	uint32_t align = (attr >> 3) & 7, arg = attr & 7;
	switch (arg) {
	case ATOM_ARG_REG:
	case ATOM_ARG_ID:
		(*ptr) += 2;
		break;
	case ATOM_ARG_PLL:
	case ATOM_ARG_MC:
	case ATOM_ARG_PS:
	case ATOM_ARG_WS:
	case ATOM_ARG_FB:
		(*ptr)++;
		break;
	case ATOM_ARG_IMM:
		switch (align) {
		case ATOM_SRC_DWORD:
			(*ptr) += 4;
			return;
		case ATOM_SRC_WORD0:
		case ATOM_SRC_WORD8:
		case ATOM_SRC_WORD16:
			(*ptr) += 2;
			return;
		case ATOM_SRC_BYTE0:
		case ATOM_SRC_BYTE8:
		case ATOM_SRC_BYTE16:
		case ATOM_SRC_BYTE24:
			(*ptr)++;
			return;
		}
		return;
	}
}

static uint32_t atom_get_src(atom_exec_context *ctx, uint8_t attr, int *ptr)
{
	return atom_get_src_int(ctx, attr, ptr, NULL, 1);
}

static uint32_t atom_get_src_direct(atom_exec_context *ctx, uint8_t align, int *ptr)
{
	uint32_t val = 0xCDCDCDCD;

	switch (align) {
	case ATOM_SRC_DWORD:
		val = U32(*ptr);
		(*ptr) += 4;
		break;
	case ATOM_SRC_WORD0:
	case ATOM_SRC_WORD8:
	case ATOM_SRC_WORD16:
		val = U16(*ptr);
		(*ptr) += 2;
		break;
	case ATOM_SRC_BYTE0:
	case ATOM_SRC_BYTE8:
	case ATOM_SRC_BYTE16:
	case ATOM_SRC_BYTE24:
		val = U8(*ptr);
		(*ptr)++;
		break;
	}
	return val;
}

static uint32_t atom_get_dst(atom_exec_context *ctx, int arg, uint8_t attr,
			     int *ptr, uint32_t *saved, int print)
{
	return atom_get_src_int(ctx,
				arg | atom_dst_to_src[(attr >> 3) &
						      7][(attr >> 6) & 3] << 3,
				ptr, saved, print);
}

static void atom_skip_dst(atom_exec_context *ctx, int arg, uint8_t attr, int *ptr)
{
	atom_skip_src_int(ctx,
			  arg | atom_dst_to_src[(attr >> 3) & 7][(attr >> 6) &
								 3] << 3, ptr);
}

static void atom_put_dst(atom_exec_context *ctx, int arg, uint8_t attr,
			 int *ptr, uint32_t val, uint32_t saved)
{
	uint32_t align =
	    atom_dst_to_src[(attr >> 3) & 7][(attr >> 6) & 3], old_val =
	    val, idx;
	struct atom_context *gctx = ctx->ctx;
	old_val &= atom_arg_mask[align] >> atom_arg_shift[align];
	val <<= atom_arg_shift[align];
	val &= atom_arg_mask[align];
	saved &= ~atom_arg_mask[align];
	val |= saved;
	switch (arg) {
	case ATOM_ARG_REG:
		idx = U16(*ptr);
		(*ptr) += 2;
		DEBUG("REG[0x%04X]", idx);
		idx += gctx->reg_block;
		switch (gctx->io_mode) {
		case ATOM_IO_MM:
			if (idx == 0)
				gctx->card->reg_write(gctx->card, idx,
						      val << 2);
			else
				gctx->card->reg_write(gctx->card, idx, val);
			break;
		case ATOM_IO_PCI:
			printk(KERN_INFO
			       "PCI registers are not implemented.\n");
			return;
		case ATOM_IO_SYSIO:
			printk(KERN_INFO
			       "SYSIO registers are not implemented.\n");
			return;
		default:
			if (!(gctx->io_mode & 0x80)) {
				printk(KERN_INFO "Bad IO mode.\n");
				return;
			}
			if (!gctx->iio[gctx->io_mode & 0xFF]) {
				printk(KERN_INFO
				       "Undefined indirect IO write method %d.\n",
				       gctx->io_mode & 0x7F);
				return;
			}
			atom_iio_execute(gctx, gctx->iio[gctx->io_mode & 0xFF],
					 idx, val);
		}
		break;
	case ATOM_ARG_PS:
		idx = U8(*ptr);
		(*ptr)++;
		DEBUG("PS[0x%02X]", idx);
		ctx->ps[idx] = cpu_to_le32(val);
		break;
	case ATOM_ARG_WS:
		idx = U8(*ptr);
		(*ptr)++;
		DEBUG("WS[0x%02X]", idx);
		switch (idx) {
		case ATOM_WS_QUOTIENT:
			gctx->divmul[0] = val;
			break;
		case ATOM_WS_REMAINDER:
			gctx->divmul[1] = val;
			break;
		case ATOM_WS_DATAPTR:
			gctx->data_block = val;
			break;
		case ATOM_WS_SHIFT:
			gctx->shift = val;
			break;
		case ATOM_WS_OR_MASK:
		case ATOM_WS_AND_MASK:
			break;
		case ATOM_WS_FB_WINDOW:
			gctx->fb_base = val;
			break;
		case ATOM_WS_ATTRIBUTES:
			gctx->io_attr = val;
			break;
		case ATOM_WS_REGPTR:
			gctx->reg_block = val;
			break;
		default:
			ctx->ws[idx] = val;
		}
		break;
	case ATOM_ARG_FB:
		idx = U8(*ptr);
		(*ptr)++;
		gctx->scratch[((gctx->fb_base + idx) / 4)] = val;
		DEBUG("FB[0x%02X]", idx);
		break;
	case ATOM_ARG_PLL:
		idx = U8(*ptr);
		(*ptr)++;
		DEBUG("PLL[0x%02X]", idx);
		gctx->card->pll_write(gctx->card, idx, val);
		break;
	case ATOM_ARG_MC:
		idx = U8(*ptr);
		(*ptr)++;
		DEBUG("MC[0x%02X]", idx);
		gctx->card->mc_write(gctx->card, idx, val);
		return;
	}
	switch (align) {
	case ATOM_SRC_DWORD:
		DEBUG(".[31:0] <- 0x%08X\n", old_val);
		break;
	case ATOM_SRC_WORD0:
		DEBUG(".[15:0] <- 0x%04X\n", old_val);
		break;
	case ATOM_SRC_WORD8:
		DEBUG(".[23:8] <- 0x%04X\n", old_val);
		break;
	case ATOM_SRC_WORD16:
		DEBUG(".[31:16] <- 0x%04X\n", old_val);
		break;
	case ATOM_SRC_BYTE0:
		DEBUG(".[7:0] <- 0x%02X\n", old_val);
		break;
	case ATOM_SRC_BYTE8:
		DEBUG(".[15:8] <- 0x%02X\n", old_val);
		break;
	case ATOM_SRC_BYTE16:
		DEBUG(".[23:16] <- 0x%02X\n", old_val);
		break;
	case ATOM_SRC_BYTE24:
		DEBUG(".[31:24] <- 0x%02X\n", old_val);
		break;
	}
}

static void atom_op_add(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src, saved;
	int dptr = *ptr;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	SDEBUG("   src: ");
	src = atom_get_src(ctx, attr, ptr);
	dst += src;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_and(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src, saved;
	int dptr = *ptr;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	SDEBUG("   src: ");
	src = atom_get_src(ctx, attr, ptr);
	dst &= src;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_beep(atom_exec_context *ctx, int *ptr, int arg)
{
	printk("ATOM BIOS beeped!\n");
}

static void atom_op_calltable(atom_exec_context *ctx, int *ptr, int arg)
{
	int idx = U8((*ptr)++);
	int r = 0;

	if (idx < ATOM_TABLE_NAMES_CNT)
		SDEBUG("   table: %d (%s)\n", idx, atom_table_names[idx]);
	else
		SDEBUG("   table: %d\n", idx);
	if (U16(ctx->ctx->cmd_table + 4 + 2 * idx))
		r = atom_execute_table_locked(ctx->ctx, idx, ctx->ps + ctx->ps_shift);
	if (r) {
		ctx->abort = true;
	}
}

static void atom_op_clear(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t saved;
	int dptr = *ptr;
	attr &= 0x38;
	attr |= atom_def_dst[attr >> 3] << 6;
	atom_get_dst(ctx, arg, attr, ptr, &saved, 0);
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, 0, saved);
}

static void atom_op_compare(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src;
	SDEBUG("   src1: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, NULL, 1);
	SDEBUG("   src2: ");
	src = atom_get_src(ctx, attr, ptr);
	ctx->ctx->cs_equal = (dst == src);
	ctx->ctx->cs_above = (dst > src);
	SDEBUG("   result: %s %s\n", ctx->ctx->cs_equal ? "EQ" : "NE",
	       ctx->ctx->cs_above ? "GT" : "LE");
}

static void atom_op_delay(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t count = U8((*ptr)++);
	SDEBUG("   count: %d\n", count);
	if (arg == ATOM_UNIT_MICROSEC)
		udelay(count);
	else
		schedule_timeout_uninterruptible(msecs_to_jiffies(count));
}

static void atom_op_div(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src;
	SDEBUG("   src1: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, NULL, 1);
	SDEBUG("   src2: ");
	src = atom_get_src(ctx, attr, ptr);
	if (src != 0) {
		ctx->ctx->divmul[0] = dst / src;
		ctx->ctx->divmul[1] = dst % src;
	} else {
		ctx->ctx->divmul[0] = 0;
		ctx->ctx->divmul[1] = 0;
	}
}

static void atom_op_eot(atom_exec_context *ctx, int *ptr, int arg)
{
	/* functionally, a nop */
}

static void atom_op_jump(atom_exec_context *ctx, int *ptr, int arg)
{
	int execute = 0, target = U16(*ptr);
	unsigned long cjiffies;

	(*ptr) += 2;
	switch (arg) {
	case ATOM_COND_ABOVE:
		execute = ctx->ctx->cs_above;
		break;
	case ATOM_COND_ABOVEOREQUAL:
		execute = ctx->ctx->cs_above || ctx->ctx->cs_equal;
		break;
	case ATOM_COND_ALWAYS:
		execute = 1;
		break;
	case ATOM_COND_BELOW:
		execute = !(ctx->ctx->cs_above || ctx->ctx->cs_equal);
		break;
	case ATOM_COND_BELOWOREQUAL:
		execute = !ctx->ctx->cs_above;
		break;
	case ATOM_COND_EQUAL:
		execute = ctx->ctx->cs_equal;
		break;
	case ATOM_COND_NOTEQUAL:
		execute = !ctx->ctx->cs_equal;
		break;
	}
	if (arg != ATOM_COND_ALWAYS)
		SDEBUG("   taken: %s\n", execute ? "yes" : "no");
	SDEBUG("   target: 0x%04X\n", target);
	if (execute) {
		if (ctx->last_jump == (ctx->start + target)) {
			cjiffies = jiffies;
			if (time_after(cjiffies, ctx->last_jump_jiffies)) {
				cjiffies -= ctx->last_jump_jiffies;
				if ((jiffies_to_msecs(cjiffies) > 1000)) {
					DRM_ERROR("atombios stuck in loop for more than 1sec aborting\n");
					ctx->abort = true;
				}
			} else {
				/* jiffies wrap around we will just wait a little longer */
				ctx->last_jump_jiffies = jiffies;
			}
		} else {
			ctx->last_jump = ctx->start + target;
			ctx->last_jump_jiffies = jiffies;
		}
		*ptr = ctx->start + target;
	}
}

static void atom_op_mask(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src1, src2, saved;
	int dptr = *ptr;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	SDEBUG("   src1: ");
	src1 = atom_get_src_direct(ctx, ((attr >> 3) & 7), ptr);
	SDEBUG("   src2: ");
	src2 = atom_get_src(ctx, attr, ptr);
	dst &= src1;
	dst |= src2;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_move(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t src, saved;
	int dptr = *ptr;
	if (((attr >> 3) & 7) != ATOM_SRC_DWORD)
		atom_get_dst(ctx, arg, attr, ptr, &saved, 0);
	else {
		atom_skip_dst(ctx, arg, attr, ptr);
		saved = 0xCDCDCDCD;
	}
	SDEBUG("   src: ");
	src = atom_get_src(ctx, attr, ptr);
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, src, saved);
}

static void atom_op_mul(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src;
	SDEBUG("   src1: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, NULL, 1);
	SDEBUG("   src2: ");
	src = atom_get_src(ctx, attr, ptr);
	ctx->ctx->divmul[0] = dst * src;
}

static void atom_op_nop(atom_exec_context *ctx, int *ptr, int arg)
{
	/* nothing */
}

static void atom_op_or(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src, saved;
	int dptr = *ptr;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	SDEBUG("   src: ");
	src = atom_get_src(ctx, attr, ptr);
	dst |= src;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_postcard(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t val = U8((*ptr)++);
	SDEBUG("POST card output: 0x%02X\n", val);
}

static void atom_op_repeat(atom_exec_context *ctx, int *ptr, int arg)
{
	printk(KERN_INFO "unimplemented!\n");
}

static void atom_op_restorereg(atom_exec_context *ctx, int *ptr, int arg)
{
	printk(KERN_INFO "unimplemented!\n");
}

static void atom_op_savereg(atom_exec_context *ctx, int *ptr, int arg)
{
	printk(KERN_INFO "unimplemented!\n");
}

static void atom_op_setdatablock(atom_exec_context *ctx, int *ptr, int arg)
{
	int idx = U8(*ptr);
	(*ptr)++;
	SDEBUG("   block: %d\n", idx);
	if (!idx)
		ctx->ctx->data_block = 0;
	else if (idx == 255)
		ctx->ctx->data_block = ctx->start;
	else
		ctx->ctx->data_block = U16(ctx->ctx->data_table + 4 + 2 * idx);
	SDEBUG("   base: 0x%04X\n", ctx->ctx->data_block);
}

static void atom_op_setfbbase(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	SDEBUG("   fb_base: ");
	ctx->ctx->fb_base = atom_get_src(ctx, attr, ptr);
}

static void atom_op_setport(atom_exec_context *ctx, int *ptr, int arg)
{
	int port;
	switch (arg) {
	case ATOM_PORT_ATI:
		port = U16(*ptr);
		if (port < ATOM_IO_NAMES_CNT)
			SDEBUG("   port: %d (%s)\n", port, atom_io_names[port]);
		else
			SDEBUG("   port: %d\n", port);
		if (!port)
			ctx->ctx->io_mode = ATOM_IO_MM;
		else
			ctx->ctx->io_mode = ATOM_IO_IIO | port;
		(*ptr) += 2;
		break;
	case ATOM_PORT_PCI:
		ctx->ctx->io_mode = ATOM_IO_PCI;
		(*ptr)++;
		break;
	case ATOM_PORT_SYSIO:
		ctx->ctx->io_mode = ATOM_IO_SYSIO;
		(*ptr)++;
		break;
	}
}

static void atom_op_setregblock(atom_exec_context *ctx, int *ptr, int arg)
{
	ctx->ctx->reg_block = U16(*ptr);
	(*ptr) += 2;
	SDEBUG("   base: 0x%04X\n", ctx->ctx->reg_block);
}

static void atom_op_shift_left(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++), shift;
	uint32_t saved, dst;
	int dptr = *ptr;
	attr &= 0x38;
	attr |= atom_def_dst[attr >> 3] << 6;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	shift = atom_get_src_direct(ctx, ATOM_SRC_BYTE0, ptr);
	SDEBUG("   shift: %d\n", shift);
	dst <<= shift;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_shift_right(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++), shift;
	uint32_t saved, dst;
	int dptr = *ptr;
	attr &= 0x38;
	attr |= atom_def_dst[attr >> 3] << 6;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	shift = atom_get_src_direct(ctx, ATOM_SRC_BYTE0, ptr);
	SDEBUG("   shift: %d\n", shift);
	dst >>= shift;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_shl(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++), shift;
	uint32_t saved, dst;
	int dptr = *ptr;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	shift = atom_get_src(ctx, attr, ptr);
	SDEBUG("   shift: %d\n", shift);
	dst <<= shift;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_shr(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++), shift;
	uint32_t saved, dst;
	int dptr = *ptr;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	shift = atom_get_src(ctx, attr, ptr);
	SDEBUG("   shift: %d\n", shift);
	dst >>= shift;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_sub(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src, saved;
	int dptr = *ptr;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	SDEBUG("   src: ");
	src = atom_get_src(ctx, attr, ptr);
	dst -= src;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_switch(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t src, val, target;
	SDEBUG("   switch: ");
	src = atom_get_src(ctx, attr, ptr);
	while (U16(*ptr) != ATOM_CASE_END)
		if (U8(*ptr) == ATOM_CASE_MAGIC) {
			(*ptr)++;
			SDEBUG("   case: ");
			val =
			    atom_get_src(ctx, (attr & 0x38) | ATOM_ARG_IMM,
					 ptr);
			target = U16(*ptr);
			if (val == src) {
				SDEBUG("   target: %04X\n", target);
				*ptr = ctx->start + target;
				return;
			}
			(*ptr) += 2;
		} else {
			printk(KERN_INFO "Bad case.\n");
			return;
		}
	(*ptr) += 2;
}

static void atom_op_test(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src;
	SDEBUG("   src1: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, NULL, 1);
	SDEBUG("   src2: ");
	src = atom_get_src(ctx, attr, ptr);
	ctx->ctx->cs_equal = ((dst & src) == 0);
	SDEBUG("   result: %s\n", ctx->ctx->cs_equal ? "EQ" : "NE");
}

static void atom_op_xor(atom_exec_context *ctx, int *ptr, int arg)
{
	uint8_t attr = U8((*ptr)++);
	uint32_t dst, src, saved;
	int dptr = *ptr;
	SDEBUG("   dst: ");
	dst = atom_get_dst(ctx, arg, attr, ptr, &saved, 1);
	SDEBUG("   src: ");
	src = atom_get_src(ctx, attr, ptr);
	dst ^= src;
	SDEBUG("   dst: ");
	atom_put_dst(ctx, arg, attr, &dptr, dst, saved);
}

static void atom_op_debug(atom_exec_context *ctx, int *ptr, int arg)
{
	printk(KERN_INFO "unimplemented!\n");
}

static struct {
	void (*func) (atom_exec_context *, int *, int);
	int arg;
} opcode_table[ATOM_OP_CNT] = {
	{
	NULL, 0}, {
	atom_op_move, ATOM_ARG_REG}, {
	atom_op_move, ATOM_ARG_PS}, {
	atom_op_move, ATOM_ARG_WS}, {
	atom_op_move, ATOM_ARG_FB}, {
	atom_op_move, ATOM_ARG_PLL}, {
	atom_op_move, ATOM_ARG_MC}, {
	atom_op_and, ATOM_ARG_REG}, {
	atom_op_and, ATOM_ARG_PS}, {
	atom_op_and, ATOM_ARG_WS}, {
	atom_op_and, ATOM_ARG_FB}, {
	atom_op_and, ATOM_ARG_PLL}, {
	atom_op_and, ATOM_ARG_MC}, {
	atom_op_or, ATOM_ARG_REG}, {
	atom_op_or, ATOM_ARG_PS}, {
	atom_op_or, ATOM_ARG_WS}, {
	atom_op_or, ATOM_ARG_FB}, {
	atom_op_or, ATOM_ARG_PLL}, {
	atom_op_or, ATOM_ARG_MC}, {
	atom_op_shift_left, ATOM_ARG_REG}, {
	atom_op_shift_left, ATOM_ARG_PS}, {
	atom_op_shift_left, ATOM_ARG_WS}, {
	atom_op_shift_left, ATOM_ARG_FB}, {
	atom_op_shift_left, ATOM_ARG_PLL}, {
	atom_op_shift_left, ATOM_ARG_MC}, {
	atom_op_shift_right, ATOM_ARG_REG}, {
	atom_op_shift_right, ATOM_ARG_PS}, {
	atom_op_shift_right, ATOM_ARG_WS}, {
	atom_op_shift_right, ATOM_ARG_FB}, {
	atom_op_shift_right, ATOM_ARG_PLL}, {
	atom_op_shift_right, ATOM_ARG_MC}, {
	atom_op_mul, ATOM_ARG_REG}, {
	atom_op_mul, ATOM_ARG_PS}, {
	atom_op_mul, ATOM_ARG_WS}, {
	atom_op_mul, ATOM_ARG_FB}, {
	atom_op_mul, ATOM_ARG_PLL}, {
	atom_op_mul, ATOM_ARG_MC}, {
	atom_op_div, ATOM_ARG_REG}, {
	atom_op_div, ATOM_ARG_PS}, {
	atom_op_div, ATOM_ARG_WS}, {
	atom_op_div, ATOM_ARG_FB}, {
	atom_op_div, ATOM_ARG_PLL}, {
	atom_op_div, ATOM_ARG_MC}, {
	atom_op_add, ATOM_ARG_REG}, {
	atom_op_add, ATOM_ARG_PS}, {
	atom_op_add, ATOM_ARG_WS}, {
	atom_op_add, ATOM_ARG_FB}, {
	atom_op_add, ATOM_ARG_PLL}, {
	atom_op_add, ATOM_ARG_MC}, {
	atom_op_sub, ATOM_ARG_REG}, {
	atom_op_sub, ATOM_ARG_PS}, {
	atom_op_sub, ATOM_ARG_WS}, {
	atom_op_sub, ATOM_ARG_FB}, {
	atom_op_sub, ATOM_ARG_PLL}, {
	atom_op_sub, ATOM_ARG_MC}, {
	atom_op_setport, ATOM_PORT_ATI}, {
	atom_op_setport, ATOM_PORT_PCI}, {
	atom_op_setport, ATOM_PORT_SYSIO}, {
	atom_op_setregblock, 0}, {
	atom_op_setfbbase, 0}, {
	atom_op_compare, ATOM_ARG_REG}, {
	atom_op_compare, ATOM_ARG_PS}, {
	atom_op_compare, ATOM_ARG_WS}, {
	atom_op_compare, ATOM_ARG_FB}, {
	atom_op_compare, ATOM_ARG_PLL}, {
	atom_op_compare, ATOM_ARG_MC}, {
	atom_op_switch, 0}, {
	atom_op_jump, ATOM_COND_ALWAYS}, {
	atom_op_jump, ATOM_COND_EQUAL}, {
	atom_op_jump, ATOM_COND_BELOW}, {
	atom_op_jump, ATOM_COND_ABOVE}, {
	atom_op_jump, ATOM_COND_BELOWOREQUAL}, {
	atom_op_jump, ATOM_COND_ABOVEOREQUAL}, {
	atom_op_jump, ATOM_COND_NOTEQUAL}, {
	atom_op_test, ATOM_ARG_REG}, {
	atom_op_test, ATOM_ARG_PS}, {
	atom_op_test, ATOM_ARG_WS}, {
	atom_op_test, ATOM_ARG_FB}, {
	atom_op_test, ATOM_ARG_PLL}, {
	atom_op_test, ATOM_ARG_MC}, {
	atom_op_delay, ATOM_UNIT_MILLISEC}, {
	atom_op_delay, ATOM_UNIT_MICROSEC}, {
	atom_op_calltable, 0}, {
	atom_op_repeat, 0}, {
	atom_op_clear, ATOM_ARG_REG}, {
	atom_op_clear, ATOM_ARG_PS}, {
	atom_op_clear, ATOM_ARG_WS}, {
	atom_op_clear, ATOM_ARG_FB}, {
	atom_op_clear, ATOM_ARG_PLL}, {
	atom_op_clear, ATOM_ARG_MC}, {
	atom_op_nop, 0}, {
	atom_op_eot, 0}, {
	atom_op_mask, ATOM_ARG_REG}, {
	atom_op_mask, ATOM_ARG_PS}, {
	atom_op_mask, ATOM_ARG_WS}, {
	atom_op_mask, ATOM_ARG_FB}, {
	atom_op_mask, ATOM_ARG_PLL}, {
	atom_op_mask, ATOM_ARG_MC}, {
	atom_op_postcard, 0}, {
	atom_op_beep, 0}, {
	atom_op_savereg, 0}, {
	atom_op_restorereg, 0}, {
	atom_op_setdatablock, 0}, {
	atom_op_xor, ATOM_ARG_REG}, {
	atom_op_xor, ATOM_ARG_PS}, {
	atom_op_xor, ATOM_ARG_WS}, {
	atom_op_xor, ATOM_ARG_FB}, {
	atom_op_xor, ATOM_ARG_PLL}, {
	atom_op_xor, ATOM_ARG_MC}, {
	atom_op_shl, ATOM_ARG_REG}, {
	atom_op_shl, ATOM_ARG_PS}, {
	atom_op_shl, ATOM_ARG_WS}, {
	atom_op_shl, ATOM_ARG_FB}, {
	atom_op_shl, ATOM_ARG_PLL}, {
	atom_op_shl, ATOM_ARG_MC}, {
	atom_op_shr, ATOM_ARG_REG}, {
	atom_op_shr, ATOM_ARG_PS}, {
	atom_op_shr, ATOM_ARG_WS}, {
	atom_op_shr, ATOM_ARG_FB}, {
	atom_op_shr, ATOM_ARG_PLL}, {
	atom_op_shr, ATOM_ARG_MC}, {
atom_op_debug, 0},};

static int atom_execute_table_locked(struct atom_context *ctx, int index, uint32_t * params)
{
	int base = CU16(ctx->cmd_table + 4 + 2 * index);
	int len, ws, ps, ptr;
	unsigned char op;
	atom_exec_context ectx;

	if (!base)
		return -EINVAL;

	len = CU16(base + ATOM_CT_SIZE_PTR);
	ws = CU8(base + ATOM_CT_WS_PTR);
	ps = CU8(base + ATOM_CT_PS_PTR) & ATOM_CT_PS_MASK;
	ptr = base + ATOM_CT_CODE_PTR;

	SDEBUG(">> execute %04X (len %d, WS %d, PS %d)\n", base, len, ws, ps);

	ectx.ctx = ctx;
	ectx.ps_shift = ps / 4;
	ectx.start = base;
	ectx.ps = params;
	ectx.abort = false;
	ectx.last_jump = 0;
	if (ws)
		ectx.ws = kzalloc(4 * ws, GFP_KERNEL);
	else
		ectx.ws = NULL;

	debug_depth++;
	while (1) {
		op = CU8(ptr++);
		if (op < ATOM_OP_NAMES_CNT)
			SDEBUG("%s @ 0x%04X\n", atom_op_names[op], ptr - 1);
		else
			SDEBUG("[%d] @ 0x%04X\n", op, ptr - 1);
		if (ectx.abort) {
			DRM_ERROR("atombios stuck executing %04X (len %d, WS %d, PS %d) @ 0x%04X\n",
				base, len, ws, ps, ptr - 1);
			return -EINVAL;
		}

		if (op < ATOM_OP_CNT && op > 0)
			opcode_table[op].func(&ectx, &ptr,
					      opcode_table[op].arg);
		else
			break;

		if (op == ATOM_OP_EOT)
			break;
	}
	debug_depth--;
	SDEBUG("<<\n");

	if (ws)
		kfree(ectx.ws);
	return 0;
}

int atom_execute_table(struct atom_context *ctx, int index, uint32_t * params)
{
	int r;

	mutex_lock(&ctx->mutex);
	/* reset reg block */
	ctx->reg_block = 0;
	/* reset fb window */
	ctx->fb_base = 0;
	/* reset io mode */
	ctx->io_mode = ATOM_IO_MM;
	r = atom_execute_table_locked(ctx, index, params);
	mutex_unlock(&ctx->mutex);
	return r;
}

static int atom_iio_len[] = { 1, 2, 3, 3, 3, 3, 4, 4, 4, 3 };

static void atom_index_iio(struct atom_context *ctx, int base)
{
	ctx->iio = kzalloc(2 * 256, GFP_KERNEL);
	while (CU8(base) == ATOM_IIO_START) {
		ctx->iio[CU8(base + 1)] = base + 2;
		base += 2;
		while (CU8(base) != ATOM_IIO_END)
			base += atom_iio_len[CU8(base)];
		base += 3;
	}
}

struct atom_context *atom_parse(struct card_info *card, void *bios)
{
	int base;
	struct atom_context *ctx =
	    kzalloc(sizeof(struct atom_context), GFP_KERNEL);
	char *str;
	char name[512];
	int i;

	ctx->card = card;
	ctx->bios = bios;

	if (CU16(0) != ATOM_BIOS_MAGIC) {
		printk(KERN_INFO "Invalid BIOS magic.\n");
		kfree(ctx);
		return NULL;
	}
	if (strncmp
	    (CSTR(ATOM_ATI_MAGIC_PTR), ATOM_ATI_MAGIC,
	     strlen(ATOM_ATI_MAGIC))) {
		printk(KERN_INFO "Invalid ATI magic.\n");
		kfree(ctx);
		return NULL;
	}

	base = CU16(ATOM_ROM_TABLE_PTR);
	if (strncmp
	    (CSTR(base + ATOM_ROM_MAGIC_PTR), ATOM_ROM_MAGIC,
	     strlen(ATOM_ROM_MAGIC))) {
		printk(KERN_INFO "Invalid ATOM magic.\n");
		kfree(ctx);
		return NULL;
	}

	ctx->cmd_table = CU16(base + ATOM_ROM_CMD_PTR);
	ctx->data_table = CU16(base + ATOM_ROM_DATA_PTR);
	atom_index_iio(ctx, CU16(ctx->data_table + ATOM_DATA_IIO_PTR) + 4);

	str = CSTR(CU16(base + ATOM_ROM_MSG_PTR));
	while (*str && ((*str == '\n') || (*str == '\r')))
		str++;
	/* name string isn't always 0 terminated */
	for (i = 0; i < 511; i++) {
		name[i] = str[i];
		if (name[i] < '.' || name[i] > 'z') {
			name[i] = 0;
			break;
		}
	}
	printk(KERN_INFO "ATOM BIOS: %s\n", name);

	return ctx;
}

int atom_asic_init(struct atom_context *ctx)
{
	int hwi = CU16(ctx->data_table + ATOM_DATA_FWI_PTR);
	uint32_t ps[16];
	memset(ps, 0, 64);

	ps[0] = cpu_to_le32(CU32(hwi + ATOM_FWI_DEFSCLK_PTR));
	ps[1] = cpu_to_le32(CU32(hwi + ATOM_FWI_DEFMCLK_PTR));
	if (!ps[0] || !ps[1])
		return 1;

	if (!CU16(ctx->cmd_table + 4 + 2 * ATOM_CMD_INIT))
		return 1;
	return atom_execute_table(ctx, ATOM_CMD_INIT, ps);
}

void atom_destroy(struct atom_context *ctx)
{
	if (ctx->iio)
		kfree(ctx->iio);
	kfree(ctx);
}

void atom_parse_data_header(struct atom_context *ctx, int index,
			    uint16_t * size, uint8_t * frev, uint8_t * crev,
			    uint16_t * data_start)
{
	int offset = index * 2 + 4;
	int idx = CU16(ctx->data_table + offset);

	if (size)
		*size = CU16(idx);
	if (frev)
		*frev = CU8(idx + 2);
	if (crev)
		*crev = CU8(idx + 3);
	*data_start = idx;
	return;
}

void atom_parse_cmd_header(struct atom_context *ctx, int index, uint8_t * frev,
			   uint8_t * crev)
{
	int offset = index * 2 + 4;
	int idx = CU16(ctx->cmd_table + offset);

	if (frev)
		*frev = CU8(idx + 2);
	if (crev)
		*crev = CU8(idx + 3);
	return;
}

int atom_allocate_fb_scratch(struct atom_context *ctx)
{
	int index = GetIndexIntoMasterTable(DATA, VRAM_UsageByFirmware);
	uint16_t data_offset;
	int usage_bytes;
	struct _ATOM_VRAM_USAGE_BY_FIRMWARE *firmware_usage;

	atom_parse_data_header(ctx, index, NULL, NULL, NULL, &data_offset);

	firmware_usage = (struct _ATOM_VRAM_USAGE_BY_FIRMWARE *)(ctx->bios + data_offset);

	DRM_DEBUG("atom firmware requested %08x %dkb\n",
		  firmware_usage->asFirmwareVramReserveInfo[0].ulStartAddrUsedByFirmware,
		  firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb);

	usage_bytes = firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb * 1024;
	if (usage_bytes == 0)
		usage_bytes = 20 * 1024;
	/* allocate some scratch memory */
	ctx->scratch = kzalloc(usage_bytes, GFP_KERNEL);
	if (!ctx->scratch)
		return -ENOMEM;
	return 0;
}