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Subject[PATCH v2 3/5] mm: ioremap: Add arch_ioremap/iounmap()
Date
Add special hook for architecture to verify addr, size and prot
or setup when ioremap() or iounmap(), which will make the generic
ioremap more useful.

arch_ioremap() return a 'void __iomem *',
- IS_ERR means return an error
- NULL means continue to remap
- a non-NULL, non-IS_ERR pointer is directly returned
arch_iounmap() return a int value,
- 0 means continue to vunmap
- error code means skip vunmap and return directly

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
include/asm-generic/io.h | 14 ++++++++++++++
mm/ioremap.c | 14 +++++++++++++-
2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index e6ffa2519f08..f2f9aeedb5e8 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -964,6 +964,20 @@ static inline void iounmap(volatile void __iomem *addr)
#elif defined(CONFIG_GENERIC_IOREMAP)
#include <linux/pgtable.h>

+#ifndef arch_ioremap
+static inline void __iomem *arch_ioremap(phys_addr_t phys_addr, size_t size, unsigned long prot)
+{
+ return NULL;
+}
+#endif
+
+#ifndef arch_iounmap
+static inline int arch_iounmap(void __iomem *addr)
+{
+ return 0;
+}
+#endif
+
void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, unsigned long prot);
void iounmap(volatile void __iomem *addr);

diff --git a/mm/ioremap.c b/mm/ioremap.c
index 7cb9996b0c12..de5a2e899e14 100644
--- a/mm/ioremap.c
+++ b/mm/ioremap.c
@@ -16,6 +16,7 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, unsigned long pro
unsigned long offset, vaddr;
phys_addr_t last_addr;
struct vm_struct *area;
+ void __iomem *base;

/* Disallow wrap-around or zero size */
last_addr = phys_addr + size - 1;
@@ -27,6 +28,12 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, unsigned long pro
phys_addr -= offset;
size = PAGE_ALIGN(size + offset);

+ base = arch_ioremap(phys_addr, size, prot);
+ if (IS_ERR(base))
+ return NULL;
+ else if (base)
+ return base;
+
area = get_vm_area_caller(size, VM_IOREMAP,
__builtin_return_address(0));
if (!area)
@@ -45,6 +52,11 @@ EXPORT_SYMBOL(ioremap_prot);

void iounmap(volatile void __iomem *addr)
{
- vunmap((void *)((unsigned long)addr & PAGE_MASK));
+ void *vaddr = (void *)((unsigned long)addr & PAGE_MASK);
+
+ if (arch_iounmap(vaddr))
+ return;
+
+ vunmap(vaddr);
}
EXPORT_SYMBOL(iounmap);
--
2.35.3
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