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Message-ID: <20220519082552.117736-5-wangkefeng.wang@huawei.com>
Date: Thu, 19 May 2022 16:25:50 +0800
From: Kefeng Wang <wangkefeng.wang@...wei.com>
To: <catalin.marinas@....com>, <will@...nel.org>,
<akpm@...ux-foundation.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>
CC: <linux-mm@...ck.org>, <hch@...radead.org>, <arnd@...db.de>,
<anshuman.khandual@....com>,
Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH v3 4/6] mm: ioremap: Add arch_ioremap/iounmap()
Add special hook for architecture to verify or setup addr, size
or prot when ioremap() or iounmap(), which will make the generic
ioremap more useful.
arch_ioremap() return a pointer,
- 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@...wei.com>
---
include/asm-generic/io.h | 24 ++++++++++++++++++++++++
mm/ioremap.c | 17 ++++++++++++++---
2 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index e6ffa2519f08..b60f7151e1d6 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -964,6 +964,30 @@ static inline void iounmap(volatile void __iomem *addr)
#elif defined(CONFIG_GENERIC_IOREMAP)
#include <linux/pgtable.h>
+/*
+ * Arch code can implement the following two special hooks when using GENERIC_IOREMAP
+ * arch_ioremap() return a pointer,
+ * - IS_ERR means return an error
+ * - NULL means continue to remap
+ * - a non-NULL, non-IS_ERR pointer is returned directly
+ * arch_iounmap() return a int,
+ * - 0 means continue to vunmap
+ * - error code means skip vunmap and return directly
+ */
+#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..fac7f23b8c4b 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;
@@ -27,8 +28,13 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size, unsigned long pro
phys_addr -= offset;
size = PAGE_ALIGN(size + offset);
- area = get_vm_area_caller(size, VM_IOREMAP,
- __builtin_return_address(0));
+ 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)
return NULL;
vaddr = (unsigned long)area->addr;
@@ -45,6 +51,11 @@ EXPORT_SYMBOL(ioremap_prot);
void iounmap(volatile void __iomem *addr)
{
- vunmap((void *)((unsigned long)addr & PAGE_MASK));
+ void __iomem *vaddr = (void __iomem *)((unsigned long)addr & PAGE_MASK);
+
+ if (arch_iounmap(vaddr))
+ return;
+
+ vunmap(vaddr);
}
EXPORT_SYMBOL(iounmap);
--
2.35.3
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