linux/arch/arm/common/sharpsl_param.c
Linus Walleij a9ff696160 ARM: mm: Make virt_to_pfn() a static inline
Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

Doing this is a bit intrusive: virt_to_pfn() requires
PHYS_PFN_OFFSET and PAGE_SHIFT to be defined, and this is defined in
<asm/page.h>, so this must be included *before* <asm/memory.h>.

The use of macros were obscuring the unclear inclusion order here,
as the macros would eventually be resolved, but a static inline
like this cannot be compiled with unresolved macros.

The naive solution to include <asm/page.h> at the top of
<asm/memory.h> does not work, because <asm/memory.h> sometimes
includes <asm/page.h> at the end of itself, which would create a
confusing inclusion loop. So instead, take the approach to always
unconditionally include <asm/page.h> at the end of <asm/memory.h>

arch/arm uses <asm/memory.h> explicitly in a lot of places,
however it turns out that if we just unconditionally include
<asm/memory.h> into <asm/page.h> and switch all inclusions of
<asm/memory.h> to <asm/page.h> instead, we enforce the right
order and <asm/memory.h> will always have access to the
definitions.

Put an inclusion guard in place making it impossible to include
<asm/memory.h> explicitly.

Link: https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2023-05-29 11:27:08 +02:00

64 lines
1.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Hardware parameter area specific to Sharp SL series devices
*
* Copyright (c) 2005 Richard Purdie
*
* Based on Sharp's 2.4 kernel patches
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <asm/mach/sharpsl_param.h>
#include <asm/page.h>
/*
* Certain hardware parameters determined at the time of device manufacture,
* typically including LCD parameters are loaded by the bootloader at the
* address PARAM_BASE. As the kernel will overwrite them, we need to store
* them early in the boot process, then pass them to the appropriate drivers.
* Not all devices use all parameters but the format is common to all.
*/
#ifdef CONFIG_ARCH_SA1100
#define PARAM_BASE 0xe8ffc000
#define param_start(x) (void *)(x)
#else
#define PARAM_BASE 0xa0000a00
#define param_start(x) __va(x)
#endif
#define MAGIC_CHG(a,b,c,d) ( ( d << 24 ) | ( c << 16 ) | ( b << 8 ) | a )
#define COMADJ_MAGIC MAGIC_CHG('C','M','A','D')
#define UUID_MAGIC MAGIC_CHG('U','U','I','D')
#define TOUCH_MAGIC MAGIC_CHG('T','U','C','H')
#define AD_MAGIC MAGIC_CHG('B','V','A','D')
#define PHAD_MAGIC MAGIC_CHG('P','H','A','D')
struct sharpsl_param_info sharpsl_param;
EXPORT_SYMBOL(sharpsl_param);
void sharpsl_save_param(void)
{
struct sharpsl_param_info *params = param_start(PARAM_BASE);
memcpy(&sharpsl_param, params, sizeof(*params));
if (sharpsl_param.comadj_keyword != COMADJ_MAGIC)
sharpsl_param.comadj=-1;
if (sharpsl_param.phad_keyword != PHAD_MAGIC)
sharpsl_param.phadadj=-1;
if (sharpsl_param.uuid_keyword != UUID_MAGIC)
sharpsl_param.uuid[0]=-1;
if (sharpsl_param.touch_keyword != TOUCH_MAGIC)
sharpsl_param.touch_xp=-1;
if (sharpsl_param.adadj_keyword != AD_MAGIC)
sharpsl_param.adadj=-1;
}