From ca2e334232b6cd4ae5af9da2df83c009d042aefb Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 5 Mar 2021 13:19:52 +0100 Subject: lib: add iomem emulation (logic_iomem) Add IO memory emulation that uses callbacks for read/write to the allocated regions. The callbacks can be registered by the users using logic_iomem_alloc(). To use, an architecture must 'select LOGIC_IOMEM' in Kconfig and then include into asm/io.h to get the __raw_read*/__raw_write* functions. Optionally, an architecture may 'select LOGIC_IOMEM_FALLBACK' in which case non-emulated regions will 'fall back' to the various real_* functions that must then be provided. Cc: Arnd Bergmann Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger --- include/linux/logic_iomem.h | 62 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 include/linux/logic_iomem.h (limited to 'include/linux/logic_iomem.h') diff --git a/include/linux/logic_iomem.h b/include/linux/logic_iomem.h new file mode 100644 index 000000000000..3fa65c964379 --- /dev/null +++ b/include/linux/logic_iomem.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2021 Intel Corporation + * Author: johannes@sipsolutions.net + */ +#ifndef __LOGIC_IOMEM_H +#define __LOGIC_IOMEM_H +#include +#include + +/** + * struct logic_iomem_ops - emulated IO memory ops + * @read: read an 8, 16, 32 or 64 bit quantity from the given offset, + * size is given in bytes (1, 2, 4 or 8) + * (64-bit only necessary if CONFIG_64BIT is set) + * @write: write an 8, 16 32 or 64 bit quantity to the given offset, + * size is given in bytes (1, 2, 4 or 8) + * (64-bit only necessary if CONFIG_64BIT is set) + * @set: optional, for memset_io() + * @copy_from: optional, for memcpy_fromio() + * @copy_to: optional, for memcpy_toio() + * @unmap: optional, this region is getting unmapped + */ +struct logic_iomem_ops { + unsigned long (*read)(void *priv, unsigned int offset, int size); + void (*write)(void *priv, unsigned int offset, int size, + unsigned long val); + + void (*set)(void *priv, unsigned int offset, u8 value, int size); + void (*copy_from)(void *priv, void *buffer, unsigned int offset, + int size); + void (*copy_to)(void *priv, unsigned int offset, const void *buffer, + int size); + + void (*unmap)(void *priv); +}; + +/** + * struct logic_iomem_region_ops - ops for an IO memory handler + * @map: map a range in the registered IO memory region, must + * fill *ops with the ops and may fill *priv to be passed + * to the ops. The offset is given as the offset into the + * registered resource region. + * The return value is negative for errors, or >= 0 for + * success. On success, the return value is added to the + * offset for later ops, to allow for partial mappings. + */ +struct logic_iomem_region_ops { + long (*map)(unsigned long offset, size_t size, + const struct logic_iomem_ops **ops, + void **priv); +}; + +/** + * logic_iomem_add_region - register an IO memory region + * @resource: the resource description for this region + * @ops: the IO memory mapping ops for this resource + */ +int logic_iomem_add_region(struct resource *resource, + const struct logic_iomem_region_ops *ops); + +#endif /* __LOGIC_IOMEM_H */ -- cgit v1.2.3-70-g09d2