xref: /kernel/linux/linux-5.10/arch/ia64/mm/ioremap.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * (c) Copyright 2006, 2007 Hewlett-Packard Development Company, L.P.
4 *	Bjorn Helgaas <bjorn.helgaas@hp.com>
5 */
6
7#include <linux/compiler.h>
8#include <linux/module.h>
9#include <linux/efi.h>
10#include <linux/io.h>
11#include <linux/mm.h>
12#include <linux/vmalloc.h>
13#include <asm/io.h>
14#include <asm/meminit.h>
15
16static inline void __iomem *
17__ioremap_uc(unsigned long phys_addr)
18{
19	return (void __iomem *) (__IA64_UNCACHED_OFFSET | phys_addr);
20}
21
22void __iomem *
23early_ioremap (unsigned long phys_addr, unsigned long size)
24{
25	u64 attr;
26	attr = kern_mem_attribute(phys_addr, size);
27	if (attr & EFI_MEMORY_WB)
28		return (void __iomem *) phys_to_virt(phys_addr);
29	return __ioremap_uc(phys_addr);
30}
31
32void __iomem *
33ioremap (unsigned long phys_addr, unsigned long size)
34{
35	void __iomem *addr;
36	struct vm_struct *area;
37	unsigned long offset;
38	pgprot_t prot;
39	u64 attr;
40	unsigned long gran_base, gran_size;
41	unsigned long page_base;
42
43	/*
44	 * For things in kern_memmap, we must use the same attribute
45	 * as the rest of the kernel.  For more details, see
46	 * Documentation/ia64/aliasing.rst.
47	 */
48	attr = kern_mem_attribute(phys_addr, size);
49	if (attr & EFI_MEMORY_WB)
50		return (void __iomem *) phys_to_virt(phys_addr);
51	else if (attr & EFI_MEMORY_UC)
52		return __ioremap_uc(phys_addr);
53
54	/*
55	 * Some chipsets don't support UC access to memory.  If
56	 * WB is supported for the whole granule, we prefer that.
57	 */
58	gran_base = GRANULEROUNDDOWN(phys_addr);
59	gran_size = GRANULEROUNDUP(phys_addr + size) - gran_base;
60	if (efi_mem_attribute(gran_base, gran_size) & EFI_MEMORY_WB)
61		return (void __iomem *) phys_to_virt(phys_addr);
62
63	/*
64	 * WB is not supported for the whole granule, so we can't use
65	 * the region 7 identity mapping.  If we can safely cover the
66	 * area with kernel page table mappings, we can use those
67	 * instead.
68	 */
69	page_base = phys_addr & PAGE_MASK;
70	size = PAGE_ALIGN(phys_addr + size) - page_base;
71	if (efi_mem_attribute(page_base, size) & EFI_MEMORY_WB) {
72		prot = PAGE_KERNEL;
73
74		/*
75		 * Mappings have to be page-aligned
76		 */
77		offset = phys_addr & ~PAGE_MASK;
78		phys_addr &= PAGE_MASK;
79
80		/*
81		 * Ok, go for it..
82		 */
83		area = get_vm_area(size, VM_IOREMAP);
84		if (!area)
85			return NULL;
86
87		area->phys_addr = phys_addr;
88		addr = (void __iomem *) area->addr;
89		if (ioremap_page_range((unsigned long) addr,
90				(unsigned long) addr + size, phys_addr, prot)) {
91			vunmap((void __force *) addr);
92			return NULL;
93		}
94
95		return (void __iomem *) (offset + (char __iomem *)addr);
96	}
97
98	return __ioremap_uc(phys_addr);
99}
100EXPORT_SYMBOL(ioremap);
101
102void __iomem *
103ioremap_uc(unsigned long phys_addr, unsigned long size)
104{
105	if (kern_mem_attribute(phys_addr, size) & EFI_MEMORY_WB)
106		return NULL;
107
108	return __ioremap_uc(phys_addr);
109}
110EXPORT_SYMBOL(ioremap_uc);
111
112void
113early_iounmap (volatile void __iomem *addr, unsigned long size)
114{
115}
116
117void
118iounmap (volatile void __iomem *addr)
119{
120	if (REGION_NUMBER(addr) == RGN_GATE)
121		vunmap((void *) ((unsigned long) addr & PAGE_MASK));
122}
123EXPORT_SYMBOL(iounmap);
124