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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Common LiteX header providing
* helper functions for accessing CSRs.
*
* Copyright (C) 2019-2020 Antmicro <www.antmicro.com>
*/
#ifndef _LINUX_LITEX_H
#define _LINUX_LITEX_H
#include <linux/io.h>
#include <asm/byteorder.h>
static inline void _write_litex_subregister(u32 val, void __iomem *addr)
{
writel((u32 __force)cpu_to_le32(val), addr);
}
static inline u32 _read_litex_subregister(void __iomem *addr)
{
return le32_to_cpu((__le32 __force)readl(addr));
}
/*
* LiteX SoC Generator, depending on the configuration, can split a single
* logical CSR (Control&Status Register) into a series of consecutive physical
* registers.
*
* For example, in the configuration with 8-bit CSR Bus, a 32-bit aligned,
* 32-bit wide logical CSR will be laid out as four 32-bit physical
* subregisters, each one containing one byte of meaningful data.
*
* For Linux support, upstream LiteX enforces a 32-bit wide CSR bus, which
* means that only larger-than-32-bit CSRs will be split across multiple
* subregisters (e.g., a 64-bit CSR will be spread across two consecutive
* 32-bit subregisters).
*
* For details see: https://github.com/enjoy-digital/litex/wiki/CSR-Bus
*/
static inline void litex_write8(void __iomem *reg, u8 val)
{
_write_litex_subregister(val, reg);
}
static inline void litex_write16(void __iomem *reg, u16 val)
{
_write_litex_subregister(val, reg);
}
static inline void litex_write32(void __iomem *reg, u32 val)
{
_write_litex_subregister(val, reg);
}
static inline void litex_write64(void __iomem *reg, u64 val)
{
_write_litex_subregister(val >> 32, reg);
_write_litex_subregister(val, reg + 4);
}
static inline u8 litex_read8(void __iomem *reg)
{
return _read_litex_subregister(reg);
}
static inline u16 litex_read16(void __iomem *reg)
{
return _read_litex_subregister(reg);
}
static inline u32 litex_read32(void __iomem *reg)
{
return _read_litex_subregister(reg);
}
static inline u64 litex_read64(void __iomem *reg)
{
return ((u64)_read_litex_subregister(reg) << 32) |
_read_litex_subregister(reg + 4);
}
#endif /* _LINUX_LITEX_H */
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