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author | Ingo Molnar <mingo@kernel.org> | 2014-02-02 09:43:20 +0100 |
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committer | Ingo Molnar <mingo@kernel.org> | 2014-02-02 09:43:20 +0100 |
commit | 65370bdf881e20907e7a53abab9b8c0bc5f60a6b (patch) | |
tree | 0d32a494e873b7b92dbfab0e67ffeef597ee8108 /arch/arm/kernel/io.c | |
parent | locking/mcs: Allow architectures to hook in to contended paths (diff) | |
parent | Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild (diff) | |
download | linux-dev-65370bdf881e20907e7a53abab9b8c0bc5f60a6b.tar.xz linux-dev-65370bdf881e20907e7a53abab9b8c0bc5f60a6b.zip |
Merge branch 'linus' into core/locking
Refresh the topic.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/arm/kernel/io.c')
-rw-r--r-- | arch/arm/kernel/io.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/arm/kernel/io.c b/arch/arm/kernel/io.c index dcd5b4d86143..9203cf883330 100644 --- a/arch/arm/kernel/io.c +++ b/arch/arm/kernel/io.c @@ -1,6 +1,41 @@ #include <linux/export.h> #include <linux/types.h> #include <linux/io.h> +#include <linux/spinlock.h> + +static DEFINE_RAW_SPINLOCK(__io_lock); + +/* + * Generic atomic MMIO modify. + * + * Allows thread-safe access to registers shared by unrelated subsystems. + * The access is protected by a single MMIO-wide lock. + */ +void atomic_io_modify_relaxed(void __iomem *reg, u32 mask, u32 set) +{ + unsigned long flags; + u32 value; + + raw_spin_lock_irqsave(&__io_lock, flags); + value = readl_relaxed(reg) & ~mask; + value |= (set & mask); + writel_relaxed(value, reg); + raw_spin_unlock_irqrestore(&__io_lock, flags); +} +EXPORT_SYMBOL(atomic_io_modify_relaxed); + +void atomic_io_modify(void __iomem *reg, u32 mask, u32 set) +{ + unsigned long flags; + u32 value; + + raw_spin_lock_irqsave(&__io_lock, flags); + value = readl_relaxed(reg) & ~mask; + value |= (set & mask); + writel(value, reg); + raw_spin_unlock_irqrestore(&__io_lock, flags); +} +EXPORT_SYMBOL(atomic_io_modify); /* * Copy data from IO memory space to "real" memory space. |