ARM: 7129/1: Add __arm_ioremap_exec for mapping external memory as MT_MEMORY

This allows mapping external memory such as SRAM for use.

This is needed for some small chunks of code, such as reprogramming
SDRAM memory source clocks that can't be executed in SDRAM. Other
use cases include some PM related code.

Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 22 insertions, 0 deletions

diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index bbeb11eda814..2e59180143a4 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -80,6 +80,7 @@ extern void __iomem *__arm_ioremap_caller(unsigned long, size_t, unsigned int,
 
 extern void __iomem *__arm_ioremap_pfn(unsigned long, unsigned long, size_t, unsigned int);
 extern void __iomem *__arm_ioremap(unsigned long, size_t, unsigned int);
+extern void __iomem *__arm_ioremap_exec(unsigned long, size_t, bool cached);
 extern void __iounmap(volatile void __iomem *addr);
 
 /*
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index ab506272b2d3..bdb248c4f55c 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -289,6 +289,27 @@ __arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype)
 }
 EXPORT_SYMBOL(__arm_ioremap);
 
+/*
+ * Remap an arbitrary physical address space into the kernel virtual
+ * address space as memory. Needed when the kernel wants to execute
+ * code in external memory. This is needed for reprogramming source
+ * clocks that would affect normal memory for example. Please see
+ * CONFIG_GENERIC_ALLOCATOR for allocating external memory.
+ */
+void __iomem *
+__arm_ioremap_exec(unsigned long phys_addr, size_t size, bool cached)
+{
+        unsigned int mtype;
+
+        if (cached)
+                mtype = MT_MEMORY;
+        else
+                mtype = MT_MEMORY_NONCACHED;
+
+        return __arm_ioremap_caller(phys_addr, size, mtype,
+                        __builtin_return_address(0));
+}
+
 void __iounmap(volatile void __iomem *io_addr)
 {
         void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);