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ad4e600cbf
Since upstream LiteX recommends that Linux support be limited to designs configured with 32-bit CSR subregisters (see commit a2b71fde in upstream LiteX, https://github.com/enjoy-digital/litex), remove the option to select 8-bit subregisters, significantly reducing the complexity of LiteX CSR (MMIO register) accessor methods. NOTE: for details on the underlying mechanics of LiteX CSR registers, see https://github.com/enjoy-digital/litex/wiki/CSR-Bus or the original LiteX accessors (litex/soc/software/include/hw/common.h in the upstream repository). Signed-off-by: Gabriel Somlo <gsomlo@gmail.com> Cc: Stafford Horne <shorne@gmail.com> Cc: Florent Kermarrec <florent@enjoy-digital.fr> Cc: Mateusz Holenko <mholenko@antmicro.com> Cc: Joel Stanley <joel@jms.id.au> Reviewed-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Stafford Horne <shorne@gmail.com>
83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Common LiteX header providing
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* helper functions for accessing CSRs.
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*
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* Copyright (C) 2019-2020 Antmicro <www.antmicro.com>
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*/
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#ifndef _LINUX_LITEX_H
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#define _LINUX_LITEX_H
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#include <linux/io.h>
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static inline void _write_litex_subregister(u32 val, void __iomem *addr)
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{
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writel((u32 __force)cpu_to_le32(val), addr);
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}
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static inline u32 _read_litex_subregister(void __iomem *addr)
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{
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return le32_to_cpu((__le32 __force)readl(addr));
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}
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/*
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* LiteX SoC Generator, depending on the configuration, can split a single
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* logical CSR (Control&Status Register) into a series of consecutive physical
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* registers.
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*
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* For example, in the configuration with 8-bit CSR Bus, a 32-bit aligned,
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* 32-bit wide logical CSR will be laid out as four 32-bit physical
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* subregisters, each one containing one byte of meaningful data.
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*
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* For Linux support, upstream LiteX enforces a 32-bit wide CSR bus, which
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* means that only larger-than-32-bit CSRs will be split across multiple
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* subregisters (e.g., a 64-bit CSR will be spread across two consecutive
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* 32-bit subregisters).
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*
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* For details see: https://github.com/enjoy-digital/litex/wiki/CSR-Bus
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*/
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static inline void litex_write8(void __iomem *reg, u8 val)
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{
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_write_litex_subregister(val, reg);
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}
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static inline void litex_write16(void __iomem *reg, u16 val)
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{
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_write_litex_subregister(val, reg);
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}
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static inline void litex_write32(void __iomem *reg, u32 val)
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{
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_write_litex_subregister(val, reg);
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}
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static inline void litex_write64(void __iomem *reg, u64 val)
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{
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_write_litex_subregister(val >> 32, reg);
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_write_litex_subregister(val, reg + 4);
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}
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static inline u8 litex_read8(void __iomem *reg)
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{
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return _read_litex_subregister(reg);
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}
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static inline u16 litex_read16(void __iomem *reg)
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{
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return _read_litex_subregister(reg);
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}
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static inline u32 litex_read32(void __iomem *reg)
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{
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return _read_litex_subregister(reg);
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}
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static inline u64 litex_read64(void __iomem *reg)
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{
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return ((u64)_read_litex_subregister(reg) << 32) |
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_read_litex_subregister(reg + 4);
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}
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#endif /* _LINUX_LITEX_H */
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