arm/kernel/io.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <linux/export.h>
0003 #include <linux/types.h>
0004 #include <linux/io.h>
0005 #include <linux/spinlock.h>
0006
0007 static DEFINE_RAW_SPINLOCK(__io_lock);
0008
0009 /*
0010  * Generic atomic MMIO modify.
0011  *
0012  * Allows thread-safe access to registers shared by unrelated subsystems.
0013  * The access is protected by a single MMIO-wide lock.
0014  */
0015 void atomic_io_modify_relaxed(void __iomem *reg, u32 mask, u32 set)
0016 {
0017     unsigned long flags;
0018     u32 value;
0019
0020     raw_spin_lock_irqsave(&__io_lock, flags);
0021     value = readl_relaxed(reg) & ~mask;
0022     value |= (set & mask);
0023     writel_relaxed(value, reg);
0024     raw_spin_unlock_irqrestore(&__io_lock, flags);
0025 }
0026 EXPORT_SYMBOL(atomic_io_modify_relaxed);
0027
0028 void atomic_io_modify(void __iomem *reg, u32 mask, u32 set)
0029 {
0030     unsigned long flags;
0031     u32 value;
0032
0033     raw_spin_lock_irqsave(&__io_lock, flags);
0034     value = readl_relaxed(reg) & ~mask;
0035     value |= (set & mask);
0036     writel(value, reg);
0037     raw_spin_unlock_irqrestore(&__io_lock, flags);
0038 }
0039 EXPORT_SYMBOL(atomic_io_modify);
0040
0041 /*
0042  * Copy data from IO memory space to "real" memory space.
0043  * This needs to be optimized.
0044  */
0045 void _memcpy_fromio(void *to, const volatile void __iomem *from, size_t count)
0046 {
0047     unsigned char *t = to;
0048     while (count) {
0049         count--;
0050         *t = readb(from);
0051         t++;
0052         from++;
0053     }
0054 }
0055 EXPORT_SYMBOL(_memcpy_fromio);
0056
0057 /*
0058  * Copy data from "real" memory space to IO memory space.
0059  * This needs to be optimized.
0060  */
0061 void _memcpy_toio(volatile void __iomem *to, const void *from, size_t count)
0062 {
0063     const unsigned char *f = from;
0064     while (count) {
0065         count--;
0066         writeb(*f, to);
0067         f++;
0068         to++;
0069     }
0070 }
0071 EXPORT_SYMBOL(_memcpy_toio);
0072
0073 /*
0074  * "memset" on IO memory space.
0075  * This needs to be optimized.
0076  */
0077 void _memset_io(volatile void __iomem *dst, int c, size_t count)
0078 {
0079     while (count) {
0080         count--;
0081         writeb(c, dst);
0082         dst++;
0083     }
0084 }
0085 EXPORT_SYMBOL(_memset_io);