1// SPDX-License-Identifier: GPL-2.0-or-later
2
3#include <linux/io.h>
4#include <linux/slab.h>
5#include <linux/vmalloc.h>
6
7void __iomem *__ioremap_caller(phys_addr_t addr, unsigned long size,
8 pgprot_t prot, void *caller)
9{
10 phys_addr_t paligned, offset;
11 void __iomem *ret;
12 int err;
13
14 /* We don't support the 4K PFN hack with ioremap */
15 if (pgprot_val(prot) & H_PAGE_4K_PFN)
16 return NULL;
17
18 /*
19 * Choose an address to map it to. Once the vmalloc system is running,
20 * we use it. Before that, we map using addresses going up from
21 * ioremap_bot. vmalloc will use the addresses from IOREMAP_BASE
22 * through ioremap_bot.
23 */
24 paligned = addr & PAGE_MASK;
25 offset = addr & ~PAGE_MASK;
26 size = PAGE_ALIGN(addr + size) - paligned;
27
28 if (size == 0 || paligned == 0)
29 return NULL;
30
31 if (slab_is_available())
32 return generic_ioremap_prot(addr, size, prot);
33
34 pr_warn("ioremap() called early from %pS. Use early_ioremap() instead\n", caller);
35
36 err = early_ioremap_range(ioremap_bot, paligned, size, prot);
37 if (err)
38 return NULL;
39
40 ret = (void __iomem *)ioremap_bot + offset;
41 ioremap_bot += size + PAGE_SIZE;
42
43 return ret;
44}
45
46/*
47 * Unmap an IO region and remove it from vmalloc'd list.
48 * Access to IO memory should be serialized by driver.
49 */
50void iounmap(volatile void __iomem *token)
51{
52 if (!slab_is_available())
53 return;
54
55 generic_iounmap(PCI_FIX_ADDR(token));
56}
57EXPORT_SYMBOL(iounmap);
58

source code of linux/arch/powerpc/mm/ioremap_64.c