1// SPDX-License-Identifier: GPL-2.0
2#include <linux/export.h>
3#include <linux/types.h>
4#include <linux/io.h>
5#include <linux/spinlock.h>
6
7static DEFINE_RAW_SPINLOCK(__io_lock);
8
9/*
10 * Generic atomic MMIO modify.
11 *
12 * Allows thread-safe access to registers shared by unrelated subsystems.
13 * The access is protected by a single MMIO-wide lock.
14 */
15void atomic_io_modify_relaxed(void __iomem *reg, u32 mask, u32 set)
16{
17 unsigned long flags;
18 u32 value;
19
20 raw_spin_lock_irqsave(&__io_lock, flags);
21 value = readl_relaxed(reg) & ~mask;
22 value |= (set & mask);
23 writel_relaxed(value, reg);
24 raw_spin_unlock_irqrestore(&__io_lock, flags);
25}
26EXPORT_SYMBOL(atomic_io_modify_relaxed);
27
28void atomic_io_modify(void __iomem *reg, u32 mask, u32 set)
29{
30 unsigned long flags;
31 u32 value;
32
33 raw_spin_lock_irqsave(&__io_lock, flags);
34 value = readl_relaxed(reg) & ~mask;
35 value |= (set & mask);
36 writel(val: value, addr: reg);
37 raw_spin_unlock_irqrestore(&__io_lock, flags);
38}
39EXPORT_SYMBOL(atomic_io_modify);
40
41/*
42 * Copy data from IO memory space to "real" memory space.
43 * This needs to be optimized.
44 */
45void _memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
46{
47 unsigned char *t = to;
48 while (count) {
49 count--;
50 *t = readb(addr: from);
51 t++;
52 from++;
53 }
54}
55EXPORT_SYMBOL(_memcpy_fromio);
56
57/*
58 * Copy data from "real" memory space to IO memory space.
59 * This needs to be optimized.
60 */
61void _memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
62{
63 const unsigned char *f = from;
64 while (count) {
65 count--;
66 writeb(val: *f, addr: to);
67 f++;
68 to++;
69 }
70}
71EXPORT_SYMBOL(_memcpy_toio);
72
73/*
74 * "memset" on IO memory space.
75 * This needs to be optimized.
76 */
77void _memset_io(volatile void __iomem *dst, int c, size_t count)
78{
79 while (count) {
80 count--;
81 writeb(val: c, addr: dst);
82 dst++;
83 }
84}
85EXPORT_SYMBOL(_memset_io);
86

source code of linux/arch/arm/kernel/io.c