diff options
| -rw-r--r-- | arch/arm/include/asm/io.h | 6 | ||||
| -rw-r--r-- | arch/arm/kernel/io.c | 35 |
2 files changed, 41 insertions, 0 deletions
diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index fbeb39c869e9..8aa4cca74501 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -38,6 +38,12 @@ #define isa_bus_to_virt phys_to_virt /* + * Atomic MMIO-wide IO modify + */ +extern void atomic_io_modify(void __iomem *reg, u32 mask, u32 set); +extern void atomic_io_modify_relaxed(void __iomem *reg, u32 mask, u32 set); + +/* * Generic IO read/write. These perform native-endian accesses. Note * that some architectures will want to re-define __raw_{read,write}w. */ 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. |