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ca2e334232
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 <asm-generic/logic_io.h> 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 <arnd@kernel.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
63 lines
2.1 KiB
C
63 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2021 Intel Corporation
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* Author: johannes@sipsolutions.net
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*/
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#ifndef __LOGIC_IOMEM_H
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#define __LOGIC_IOMEM_H
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#include <linux/types.h>
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#include <linux/ioport.h>
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/**
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* struct logic_iomem_ops - emulated IO memory ops
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* @read: read an 8, 16, 32 or 64 bit quantity from the given offset,
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* size is given in bytes (1, 2, 4 or 8)
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* (64-bit only necessary if CONFIG_64BIT is set)
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* @write: write an 8, 16 32 or 64 bit quantity to the given offset,
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* size is given in bytes (1, 2, 4 or 8)
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* (64-bit only necessary if CONFIG_64BIT is set)
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* @set: optional, for memset_io()
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* @copy_from: optional, for memcpy_fromio()
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* @copy_to: optional, for memcpy_toio()
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* @unmap: optional, this region is getting unmapped
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*/
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struct logic_iomem_ops {
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unsigned long (*read)(void *priv, unsigned int offset, int size);
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void (*write)(void *priv, unsigned int offset, int size,
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unsigned long val);
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void (*set)(void *priv, unsigned int offset, u8 value, int size);
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void (*copy_from)(void *priv, void *buffer, unsigned int offset,
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int size);
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void (*copy_to)(void *priv, unsigned int offset, const void *buffer,
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int size);
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void (*unmap)(void *priv);
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};
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/**
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* struct logic_iomem_region_ops - ops for an IO memory handler
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* @map: map a range in the registered IO memory region, must
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* fill *ops with the ops and may fill *priv to be passed
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* to the ops. The offset is given as the offset into the
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* registered resource region.
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* The return value is negative for errors, or >= 0 for
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* success. On success, the return value is added to the
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* offset for later ops, to allow for partial mappings.
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*/
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struct logic_iomem_region_ops {
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long (*map)(unsigned long offset, size_t size,
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const struct logic_iomem_ops **ops,
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void **priv);
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};
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/**
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* logic_iomem_add_region - register an IO memory region
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* @resource: the resource description for this region
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* @ops: the IO memory mapping ops for this resource
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*/
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int logic_iomem_add_region(struct resource *resource,
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const struct logic_iomem_region_ops *ops);
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#endif /* __LOGIC_IOMEM_H */
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