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author | Halil Pasic <pasic@linux.ibm.com> | 2024-03-07 13:28:05 +0100 |
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committer | Heiko Carstens <hca@linux.ibm.com> | 2024-03-13 09:23:45 +0100 |
commit | 8b19e145e82f1bf1419541de7ad823f5cb7a4ec3 (patch) | |
tree | c3a2d3c2f2f064893464908c96f10a49c3710252 /arch/s390 | |
parent | s390/vfio_ccw: fix virtual vs physical address confusion (diff) | |
download | linux-8b19e145e82f1bf1419541de7ad823f5cb7a4ec3.tar.xz linux-8b19e145e82f1bf1419541de7ad823f5cb7a4ec3.zip |
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>
Diffstat (limited to 'arch/s390')
-rw-r--r-- | arch/s390/include/asm/dma-types.h | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/arch/s390/include/asm/dma-types.h b/arch/s390/include/asm/dma-types.h new file mode 100644 index 000000000000..7d7f71022aa9 --- /dev/null +++ b/arch/s390/include/asm/dma-types.h @@ -0,0 +1,103 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_S390_DMA_TYPES_H_ +#define _ASM_S390_DMA_TYPES_H_ + +#include <linux/types.h> +#include <linux/io.h> + +/* + * typedef dma32_t + * Contains a 31 bit absolute address to a DMA capable piece of storage. + * + * For CIO, DMA addresses are always absolute addresses. These addresses tend + * to be used in architectured memory blocks (like ORB, IDAW, MIDAW). Under + * certain circumstances 31 bit wide addresses must be used because the + * address must fit in 31 bits. + * + * This type is to be used when such fields can be modelled as 32 bit wide. + */ +typedef u32 __bitwise dma32_t; + +/* + * typedef dma64_t + * Contains a 64 bit absolute address to a DMA capable piece of storage. + * + * For CIO, DMA addresses are always absolute addresses. These addresses tend + * to be used in architectured memory blocks (like ORB, IDAW, MIDAW). + * + * This type is to be used to model such 64 bit wide fields. + */ +typedef u64 __bitwise dma64_t; + +/* + * Although DMA addresses should be obtained using the DMA API, in cases when + * it is known that the first argument holds a virtual address that points to + * DMA-able 31 bit addressable storage, then this function can be safely used. + */ +static inline dma32_t virt_to_dma32(void *ptr) +{ + return (__force dma32_t)__pa(ptr); +} + +static inline void *dma32_to_virt(dma32_t addr) +{ + return __va((__force unsigned long)addr); +} + +static inline dma32_t u32_to_dma32(u32 addr) +{ + return (__force dma32_t)addr; +} + +static inline u32 dma32_to_u32(dma32_t addr) +{ + return (__force u32)addr; +} + +static inline dma32_t dma32_add(dma32_t a, u32 b) +{ + return (__force dma32_t)((__force u32)a + b); +} + +static inline dma32_t dma32_and(dma32_t a, u32 b) +{ + return (__force dma32_t)((__force u32)a & b); +} + +/* + * Although DMA addresses should be obtained using the DMA API, in cases when + * it is known that the first argument holds a virtual address that points to + * DMA-able storage, then this function can be safely used. + */ +static inline dma64_t virt_to_dma64(void *ptr) +{ + return (__force dma64_t)__pa(ptr); +} + +static inline void *dma64_to_virt(dma64_t addr) +{ + return __va((__force unsigned long)addr); +} + +static inline dma64_t u64_to_dma64(u64 addr) +{ + return (__force dma64_t)addr; +} + +static inline u64 dma64_to_u64(dma64_t addr) +{ + return (__force u64)addr; +} + +static inline dma64_t dma64_add(dma64_t a, u64 b) +{ + return (__force dma64_t)((__force u64)a + b); +} + +static inline dma64_t dma64_and(dma64_t a, u64 b) +{ + return (__force dma64_t)((__force u64)a & b); +} + +#endif /* _ASM_S390_DMA_TYPES_H_ */ |