/* SPDX-License-Identifier: GPL-2.0+ */

#ifndef _AVM_HELPERS_H_
#include <linux/version.h>
#include <linux/ktime.h>
#include <linux/timer.h>
#include <linux/fs.h>

#define LINUX_STABLE_VERSION_HAS_SUBLEVEL(a, b, c) \
	(LINUX_VERSION_CODE < KERNEL_VERSION(a, (b) + 1, 0) && \
	 LINUX_VERSION_CODE >= KERNEL_VERSION(a, b, c))

/* Return:
 *	< 0: Error (-EIO, -EPERM, -EINVAL)
 *	= 0: Empty file
 *	> 0: Number of bytes read
 */
int avm_read_from_file(const char *filename, char *str, int maxlen);

/* Return:
 *	< 0: Error (-EIO, -EPERM, -EINVAL)
 *	= 0: Success
 */
int avm_write_to_file(const char *filename, const char *str, int len);

/**
 * register_simple_dma_device - Register a simple (dummy) device for DMA
 * @dev:  The device to register
 * @name: Device name
 *
 * Register a simple device that can be used for DMA.  AVM drivers that do not
 * follow the Linux driver model but need to do DMA can hereby acquire a
 * dummy device that satisfies the requirements of the DMA API.
 *
 * There is no parent device or bus that the device is attached to.  The
 * dma_mask of the device ist unlimited.
 *
 * All fields in @dev that have no explicit value must be initialized by the
 * caller to 0.
 */
int register_simple_dma_device(struct device *dev, const char *name);

void unregister_simple_dma_device(struct device *dev);

#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 17, 0)
static inline time64_t __ktime_get_real_seconds(void)
{
	return get_seconds();
}
#endif

/* On old kernels that don't have it, we emulate ktime_get_seconds. */
time64_t ktime_get_seconds(void);

#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 19, 0)
#define rtc_time64_to_tm(a, b) rtc_time_to_tm(a, b)
#endif

#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 14, 0)
typedef void (*timer_func_t)(unsigned long);
#ifndef from_timer
#define from_timer(var, callback_timer, timer_fieldname) \
	container_of(callback_timer, typeof(*var), timer_fieldname)
#endif

#ifndef timer_setup
#ifndef __setup_timer
   /* Ancient kernels << v3.7 (puma6...), no support for timer flags */
#  define __setup_timer(_timer, _fn, _data, _flags)	\
	do {						\
		BUILD_BUG_ON(_flags);			\
		setup_timer((_timer), (_fn), (_data));	\
	} while (0)
#endif
/*
 * Unfortunately, some AVM kernel sub-projects (telephony...) enable
 * -Wextra, which implies -Wcast-function-type for gcc >= v8
 */
#pragma GCC push_options
#if __GNUC__ >= 8
#  pragma GCC diagnostic ignored "-Wcast-function-type"
#endif
#define timer_setup timer_setup
static inline void timer_setup(struct timer_list *timer,
			       void (*func)(struct timer_list *),
			       unsigned int flags)
{
	__setup_timer(timer, (timer_func_t)func, (unsigned long)timer, flags);
}
#pragma GCC pop_options
#endif /* timer_setup */

#else  /* KERNEL_VERSION */
typedef void (*timer_func_t)(struct timer_list *);
#endif

#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 14, 0)
/*
 * Upstream has re-ordered the arguments of kernel_read and kernel_write, and
 * made the loff_t arg a pointer.  Provide avm_* wrappers that use the new
 * signature.
 */
#define avm_kernel_read(file, buf, count, poff)  kernel_read(file, *(poff), buf, count)
#define avm_kernel_write(file, buf, count, poff) kernel_write(file, buf, count, *(poff))
#else
#define avm_kernel_read kernel_read
#define avm_kernel_write kernel_write
#endif

ssize_t time_to_ascii(time64_t local_time, char *buf, int len);

#ifndef fallthrough /* Linux << v5.4 */
#if __has_attribute(__fallthrough__)
# define fallthrough                    __attribute__((__fallthrough__))
#else
# define fallthrough                    do {} while (0)  /* fallthrough */
#endif
#endif /* fallthrough */

#ifndef __ro_after_init /* Linux << v4.6 */
#define __ro_after_init
#endif

#define _AVM_HELPERS_H_
#endif /* _AVM_HELPERS_H */