[PATCH] s390/io: Fix ioremap and iounmap undefinded issue for s390

[Chunyan Zhang <zhang.lyra@gmail.com>]

From: Chunyan Zhang <chunyan.zhang@unisoc.com>

There would not be ioremap and iounmap implementations if CONFIG_PCI is
not set for s390, so add default declarations of these two functionsi
for the case to avoid 'undefined reference' issue.

Fixes: 71ba41c9b1d9 ("s390/pci: provide support for MIO instructions")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
---
The issue was reported from https://lkml.org/lkml/2021/8/1/18
---
 arch/s390/include/asm/io.h | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/arch/s390/include/asm/io.h b/arch/s390/include/asm/io.h
index e3882b012bfa..9438370c6445 100644
--- a/arch/s390/include/asm/io.h
+++ b/arch/s390/include/asm/io.h
@@ -23,11 +23,8 @@ void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr);
 #define IO_SPACE_LIMIT 0
 
 void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot);
-void __iomem *ioremap(phys_addr_t addr, size_t size);
 void __iomem *ioremap_wc(phys_addr_t addr, size_t size);
 void __iomem *ioremap_wt(phys_addr_t addr, size_t size);
-void iounmap(volatile void __iomem *addr);
-
 static inline void __iomem *ioport_map(unsigned long port, unsigned int nr)
 {
 	return NULL;
@@ -39,6 +36,9 @@ static inline void ioport_unmap(void __iomem *p)
 
 #ifdef CONFIG_PCI
 
+void __iomem *ioremap(phys_addr_t addr, size_t size);
+void iounmap(volatile void __iomem *addr);
+
 /*
  * s390 needs a private implementation of pci_iomap since ioremap with its
  * offset parameter isn't sufficient. That's because BAR spaces are not
@@ -70,6 +70,15 @@ static inline void ioport_unmap(void __iomem *p)
 #define __raw_writel	zpci_write_u32
 #define __raw_writeq	zpci_write_u64
 
+#else
+static inline void __iomem *ioremap(unsigned long offset, unsigned long size)
+{
+	return (void __iomem *) offset;
+}
+
+static inline void iounmap(void __iomem *addr)
+{
+}
 #endif /* CONFIG_PCI */
 
 #include <asm-generic/io.h>
-- 
2.25.1