[PATCH v6 10/19] s390: mm: Convert to GENERIC_IOREMAP

[Baoquan He <bhe@redhat.com>]

By taking GENERIC_IOREMAP method, the generic generic_ioremap_prot(),
generic_iounmap(), and their generic wrapper ioremap_prot(), ioremap()
and iounmap() are all visible and available to arch. Arch needs to
provide wrapper functions to override the generic versions if there's
arch specific handling in its ioremap_prot(), ioremap() or iounmap().
This change will simplify implementation by removing duplicated codes
with generic_ioremap_prot() and generic_iounmap(), and has the equivalent
functioality as before.

Here, add wrapper functions ioremap_prot() and iounmap() for s390's
special operation when ioremap() and iounmap().

Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
---
 arch/s390/Kconfig          |  1 +
 arch/s390/include/asm/io.h | 21 ++++++++------
 arch/s390/pci/pci.c        | 57 +++++++-------------------------------
 3 files changed, 23 insertions(+), 56 deletions(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 6dab9c1be508..e625bb0cc6c7 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -142,6 +142,7 @@ config S390
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_TIME_VSYSCALL
 	select GENERIC_VDSO_TIME_NS
+	select GENERIC_IOREMAP if PCI
 	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_JUMP_LABEL
diff --git a/arch/s390/include/asm/io.h b/arch/s390/include/asm/io.h
index e3882b012bfa..4453ad7c11ac 100644
--- a/arch/s390/include/asm/io.h
+++ b/arch/s390/include/asm/io.h
@@ -22,11 +22,18 @@ 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);
+/*
+ * I/O memory mapping functions.
+ */
+#define ioremap_prot ioremap_prot
+#define iounmap iounmap
+
+#define _PAGE_IOREMAP pgprot_val(PAGE_KERNEL)
+
+#define ioremap_wc(addr, size)  \
+	ioremap_prot((addr), (size), pgprot_val(pgprot_writecombine(PAGE_KERNEL)))
+#define ioremap_wt(addr, size)  \
+	ioremap_prot((addr), (size), pgprot_val(pgprot_writethrough(PAGE_KERNEL)))
 
 static inline void __iomem *ioport_map(unsigned long port, unsigned int nr)
 {
@@ -51,10 +58,6 @@ static inline void ioport_unmap(void __iomem *p)
 #define pci_iomap_wc pci_iomap_wc
 #define pci_iomap_wc_range pci_iomap_wc_range
 
-#define ioremap ioremap
-#define ioremap_wt ioremap_wt
-#define ioremap_wc ioremap_wc
-
 #define memcpy_fromio(dst, src, count)	zpci_memcpy_fromio(dst, src, count)
 #define memcpy_toio(dst, src, count)	zpci_memcpy_toio(dst, src, count)
 #define memset_io(dst, val, count)	zpci_memset_io(dst, val, count)
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index afc3f33788da..d34d5813d006 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -244,62 +244,25 @@ void __iowrite64_copy(void __iomem *to, const void *from, size_t count)
        zpci_memcpy_toio(to, from, count);
 }
 
-static void __iomem *__ioremap(phys_addr_t addr, size_t size, pgprot_t prot)
+void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
+			   unsigned long prot)
 {
-	unsigned long offset, vaddr;
-	struct vm_struct *area;
-	phys_addr_t last_addr;
-
-	last_addr = addr + size - 1;
-	if (!size || last_addr < addr)
-		return NULL;
-
+	/*
+	 * When PCI MIO instructions are unavailable the "physical" address
+	 * encodes a hint for accessing the PCI memory space it represents.
+	 * Just pass it unchanged such that ioread/iowrite can decode it.
+	 */
 	if (!static_branch_unlikely(&have_mio))
-		return (void __iomem *) addr;
+		return (void __iomem *)phys_addr;
 
-	offset = addr & ~PAGE_MASK;
-	addr &= PAGE_MASK;
-	size = PAGE_ALIGN(size + offset);
-	area = get_vm_area(size, VM_IOREMAP);
-	if (!area)
-		return NULL;
-
-	vaddr = (unsigned long) area->addr;
-	if (ioremap_page_range(vaddr, vaddr + size, addr, prot)) {
-		free_vm_area(area);
-		return NULL;
-	}
-	return (void __iomem *) ((unsigned long) area->addr + offset);
-}
-
-void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot)
-{
-	return __ioremap(addr, size, __pgprot(prot));
+	return generic_ioremap_prot(phys_addr, size, __pgprot(prot));
 }
 EXPORT_SYMBOL(ioremap_prot);
 
-void __iomem *ioremap(phys_addr_t addr, size_t size)
-{
-	return __ioremap(addr, size, PAGE_KERNEL);
-}
-EXPORT_SYMBOL(ioremap);
-
-void __iomem *ioremap_wc(phys_addr_t addr, size_t size)
-{
-	return __ioremap(addr, size, pgprot_writecombine(PAGE_KERNEL));
-}
-EXPORT_SYMBOL(ioremap_wc);
-
-void __iomem *ioremap_wt(phys_addr_t addr, size_t size)
-{
-	return __ioremap(addr, size, pgprot_writethrough(PAGE_KERNEL));
-}
-EXPORT_SYMBOL(ioremap_wt);
-
 void iounmap(volatile void __iomem *addr)
 {
 	if (static_branch_likely(&have_mio))
-		vunmap((__force void *) ((unsigned long) addr & PAGE_MASK));
+		generic_iounmap(addr);
 }
 EXPORT_SYMBOL(iounmap);
 
-- 
2.34.1