s390/cio: introduce bitwise dma types and helper functions
Introduce dma32_t and dma64_t bitwise types, which are supposed to be used for 31 and 64 bit DMA capable addresses. This allows to use sparse (make C=1) for type checking, so that incorrect usages can be easily found. Also add a couple of helper functions which - convert virtual to DMA addresses and vice versa - allow for simple logical and arithmetic operations on DMA addresses - convert DMA addresses to plain u32 and u64 values All helper functions exist to avoid excessive casting in C code. Signed-off-by: Halil Pasic <pasic@linux.ibm.com> Co-developed-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_S390_DMA_TYPES_H_
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#define _ASM_S390_DMA_TYPES_H_
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#include <linux/types.h>
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#include <linux/io.h>
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/*
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* typedef dma32_t
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* Contains a 31 bit absolute address to a DMA capable piece of storage.
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*
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* For CIO, DMA addresses are always absolute addresses. These addresses tend
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* to be used in architectured memory blocks (like ORB, IDAW, MIDAW). Under
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* certain circumstances 31 bit wide addresses must be used because the
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* address must fit in 31 bits.
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*
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* This type is to be used when such fields can be modelled as 32 bit wide.
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*/
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typedef u32 __bitwise dma32_t;
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/*
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* typedef dma64_t
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* Contains a 64 bit absolute address to a DMA capable piece of storage.
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*
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* For CIO, DMA addresses are always absolute addresses. These addresses tend
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* to be used in architectured memory blocks (like ORB, IDAW, MIDAW).
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*
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* This type is to be used to model such 64 bit wide fields.
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*/
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typedef u64 __bitwise dma64_t;
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/*
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* Although DMA addresses should be obtained using the DMA API, in cases when
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* it is known that the first argument holds a virtual address that points to
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* DMA-able 31 bit addressable storage, then this function can be safely used.
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*/
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static inline dma32_t virt_to_dma32(void *ptr)
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{
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return (__force dma32_t)__pa(ptr);
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}
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static inline void *dma32_to_virt(dma32_t addr)
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{
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return __va((__force unsigned long)addr);
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}
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static inline dma32_t u32_to_dma32(u32 addr)
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{
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return (__force dma32_t)addr;
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}
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static inline u32 dma32_to_u32(dma32_t addr)
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{
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return (__force u32)addr;
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}
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static inline dma32_t dma32_add(dma32_t a, u32 b)
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{
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return (__force dma32_t)((__force u32)a + b);
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}
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static inline dma32_t dma32_and(dma32_t a, u32 b)
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{
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return (__force dma32_t)((__force u32)a & b);
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}
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/*
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* Although DMA addresses should be obtained using the DMA API, in cases when
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* it is known that the first argument holds a virtual address that points to
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* DMA-able storage, then this function can be safely used.
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*/
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static inline dma64_t virt_to_dma64(void *ptr)
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{
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return (__force dma64_t)__pa(ptr);
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}
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static inline void *dma64_to_virt(dma64_t addr)
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{
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return __va((__force unsigned long)addr);
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}
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static inline dma64_t u64_to_dma64(u64 addr)
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{
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return (__force dma64_t)addr;
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}
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static inline u64 dma64_to_u64(dma64_t addr)
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{
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return (__force u64)addr;
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}
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static inline dma64_t dma64_add(dma64_t a, u64 b)
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{
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return (__force dma64_t)((__force u64)a + b);
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}
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static inline dma64_t dma64_and(dma64_t a, u64 b)
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{
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return (__force dma64_t)((__force u64)a & b);
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}
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#endif /* _ASM_S390_DMA_TYPES_H_ */
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