On 2022/5/19 12:46, Anshuman Khandual wrote:
Hi Kefeng,
On 4/29/22 16:02, Kefeng Wang wrote:
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
Should not these comments be also included as in-code documentation, possibly
near generic fall back stubs for arch_ioremap()/arch_iounmap() in the header
include/asm-generic/io.h ?
Ok, I will add some document in io.h
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
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/arch_iounmap
@@ -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
There is a function in arch/arm/ with exact same name although the platform does
not enable GENERIC_IOREMAP. That function would require renaming for these arch
callbacks to be added here in GENERIC_IOREMAP path. Otherwise, it might be just
confusing later.
git grep "arch_iounmap" arch/arm/
arch/arm/include/asm/io.h:extern void (*arch_iounmap)(volatile void __iomem *);
arch/arm/mm/ioremap.c:void (*arch_iounmap)(volatile void __iomem *) = __iounmap;
arch/arm/mm/ioremap.c: arch_iounmap(cookie);
arch/arm/mm/nommu.c:void (*arch_iounmap)(volatile void __iomem *);
After
59d3ae9a5bf60 ("ARM: remove Intel iop33x and iop13xx support") v5.4
3e3f354bc383a ("ARM: remove ebsa110 platform") v5.11
arch_iounmap is useless, we could directly kill arch_iounmap/__iounmap
on arm,
will add new cleanup patch in v3.
+
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);
Should not this variable be 'void __iomem *vaddr' instead, like above in
ioremap_prot(). Because arch_iounmap() takes 'void __iomem *' instead.
Will do, thanks.
+
+ if (arch_iounmap(vaddr))
+ return;
+
+ vunmap(vaddr);
}
EXPORT_SYMBOL(iounmap);
- Anshuman
.
