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Revision 047fe6e6db9161e69271f56daaafdaf2add023b1 authored by David Weinehall on 04 August 2015, 13:55:52 UTC, committed by Daniel Vetter on 06 August 2015, 15:28:26 UTC 
drm/i915: Allow parsing of variable size child device entries from VBT
 
VBT version 196 increased the size of common_child_dev_config. The parser
code assumed that the size of this structure would not change.

The modified code now copies the amount needed based on the VBT version,
and emits a debug message if the VBT version is unknown (too new);
since the struct config block won't shrink in newer versions it should
be harmless to copy the maximum known size in such cases, so that's
what we do, but emitting the warning is probably sensible anyway.

In the longer run it might make sense to modify the parser code to
use a version/feature mapping, rather than hardcoding things like this,
but for now the variants are fairly managable.

This fixes a regression introduced in

commit 90e4f1592bb6e82f6690f0e05a8aadcf04d7bce7
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Wed Mar 25 18:45:58 2015 +0200

    drm/i915: Fix the VBT child device parsing for BSW

since we're hitting a DRM_ERROR on older platforms with this.

v2: Stricter size checks

Signed-off-by: David Weinehall <david.weinehall@linux.intel.com>
[danvet: Fixup format string.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
1 parent 5eb3e5a
Raw File
iomap_copy.c 
/*
 * Copyright 2006 PathScale, Inc.  All Rights Reserved.
 *
 * This file is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License
 * as published by the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include <linux/export.h>
#include <linux/io.h>

/**
 * __iowrite32_copy - copy data to MMIO space, in 32-bit units
 * @to: destination, in MMIO space (must be 32-bit aligned)
 * @from: source (must be 32-bit aligned)
 * @count: number of 32-bit quantities to copy
 *
 * Copy data from kernel space to MMIO space, in units of 32 bits at a
 * time.  Order of access is not guaranteed, nor is a memory barrier
 * performed afterwards.
 */
void __attribute__((weak)) __iowrite32_copy(void __iomem *to,
					    const void *from,
					    size_t count)
{
	u32 __iomem *dst = to;
	const u32 *src = from;
	const u32 *end = src + count;

	while (src < end)
		__raw_writel(*src++, dst++);
}
EXPORT_SYMBOL_GPL(__iowrite32_copy);

/**
 * __iowrite64_copy - copy data to MMIO space, in 64-bit or 32-bit units
 * @to: destination, in MMIO space (must be 64-bit aligned)
 * @from: source (must be 64-bit aligned)
 * @count: number of 64-bit quantities to copy
 *
 * Copy data from kernel space to MMIO space, in units of 32 or 64 bits at a
 * time.  Order of access is not guaranteed, nor is a memory barrier
 * performed afterwards.
 */
void __attribute__((weak)) __iowrite64_copy(void __iomem *to,
					    const void *from,
					    size_t count)
{
#ifdef CONFIG_64BIT
	u64 __iomem *dst = to;
	const u64 *src = from;
	const u64 *end = src + count;

	while (src < end)
		__raw_writeq(*src++, dst++);
#else
	__iowrite32_copy(to, from, count * 2);
#endif
}

EXPORT_SYMBOL_GPL(__iowrite64_copy);
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