powerpc: mm: convert to GENERIC_IOREMAP

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 code
with generic_ioremap_prot() and generic_iounmap(), and has the equivalent
functioality as before.

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

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Christophe Leroy <[e-mail]>
Signed-off-by: Baoquan He <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Mike Rapoport (IBM) <[e-mail]>
Cc: Michael Ellerman <[e-mail]>
Cc: Nicholas Piggin <[e-mail]>
Cc: Alexander Gordeev <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Brian Cain <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Christian Borntraeger <[e-mail]>
Cc: Chris Zankel <[e-mail]>
Cc: David Laight <[e-mail]>
Cc: Geert Uytterhoeven <[e-mail]>
Cc: Gerald Schaefer <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Helge Deller <[e-mail]>
Cc: "James E.J. Bottomley" <[e-mail]>
Cc: John Paul Adrian Glaubitz <[e-mail]>
Cc: Jonas Bonn <[e-mail]>
Cc: Kefeng Wang <[e-mail]>
Cc: Matthew Wilcox <[e-mail]>
Cc: Max Filippov <[e-mail]>
Cc: Nathan Chancellor <[e-mail]>
Cc: Niklas Schnelle <[e-mail]>
Cc: Rich Felker <[e-mail]>
Cc: Stafford Horne <[e-mail]>
Cc: Stefan Kristiansson <[e-mail]>
Cc: Sven Schnelle <[e-mail]>
Cc: Vasily Gorbik <[e-mail]>
Cc: Vineet Gupta <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Yoshinori Sato <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

arch/powerpc/Kconfig

···
 	select GENERIC_CPU_VULNERABILITIES	if PPC_BARRIER_NOSPEC
 	select GENERIC_EARLY_IOREMAP
 	select GENERIC_GETTIMEOFDAY
+	select GENERIC_IOREMAP
 	select GENERIC_IRQ_SHOW
 	select GENERIC_IRQ_SHOW_LEVEL
 	select GENERIC_PCI_IOMAP		if PCI

arch/powerpc/include/asm/io.h

···
  *
  */
 extern void __iomem *ioremap(phys_addr_t address, unsigned long size);
-extern void __iomem *ioremap_prot(phys_addr_t address, unsigned long size,
-				  unsigned long flags);
+#define ioremap ioremap
+#define ioremap_prot ioremap_prot
 extern void __iomem *ioremap_wc(phys_addr_t address, unsigned long size);
 #define ioremap_wc ioremap_wc
 
···
 #define ioremap_cache(addr, size) \
 	ioremap_prot((addr), (size), pgprot_val(PAGE_KERNEL))
 
-extern void iounmap(volatile void __iomem *addr);
+#define iounmap iounmap
 
 void __iomem *ioremap_phb(phys_addr_t paddr, unsigned long size);
 
 int early_ioremap_range(unsigned long ea, phys_addr_t pa,
 			unsigned long size, pgprot_t prot);
-void __iomem *do_ioremap(phys_addr_t pa, phys_addr_t offset, unsigned long size,
-			 pgprot_t prot, void *caller);
 
 extern void __iomem *__ioremap_caller(phys_addr_t, unsigned long size,
 				      pgprot_t prot, void *caller);

arch/powerpc/mm/ioremap.c

···
 	return __ioremap_caller(addr, size, prot, caller);
 }
 
-void __iomem *ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
+void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long flags)
 {
 	pte_t pte = __pte(flags);
 	void *caller = __builtin_return_address(0);
···
 	}
 
 	return 0;
-}
-
-void __iomem *do_ioremap(phys_addr_t pa, phys_addr_t offset, unsigned long size,
-			 pgprot_t prot, void *caller)
-{
-	struct vm_struct *area;
-	int ret;
-	unsigned long va;
-
-	area = __get_vm_area_caller(size, VM_IOREMAP, IOREMAP_START, IOREMAP_END, caller);
-	if (area == NULL)
-		return NULL;
-
-	area->phys_addr = pa;
-	va = (unsigned long)area->addr;
-
-	ret = ioremap_page_range(va, va + size, pa, prot);
-	if (!ret)
-		return (void __iomem *)area->addr + offset;
-
-	vunmap_range(va, va + size);
-	free_vm_area(area);
-
-	return NULL;
 }

arch/powerpc/mm/ioremap_32.c

···
 	int err;
 
 	/*
+	 * If the address lies within the first 16 MB, assume it's in ISA
+	 * memory space
+	 */
+	if (addr < SZ_16M)
+		addr += _ISA_MEM_BASE;
+
+	/*
 	 * Choose an address to map it to.
 	 * Once the vmalloc system is running, we use it.
 	 * Before then, we use space going down from IOREMAP_TOP
···
 	p = addr & PAGE_MASK;
 	offset = addr & ~PAGE_MASK;
 	size = PAGE_ALIGN(addr + size) - p;
-
-	/*
-	 * If the address lies within the first 16 MB, assume it's in ISA
-	 * memory space
-	 */
-	if (p < 16 * 1024 * 1024)
-		p += _ISA_MEM_BASE;
 
 #ifndef CONFIG_CRASH_DUMP
 	/*
···
 		return (void __iomem *)v + offset;
 
 	if (slab_is_available())
-		return do_ioremap(p, offset, size, prot, caller);
+		return generic_ioremap_prot(addr, size, prot);
 
 	/*
 	 * Should check if it is a candidate for a BAT mapping
···
 	if (v_block_mapped((unsigned long)addr))
 		return;
 
-	if (addr > high_memory && (unsigned long)addr < ioremap_bot)
-		vunmap((void *)(PAGE_MASK & (unsigned long)addr));
+	generic_iounmap(addr);
 }
 EXPORT_SYMBOL(iounmap);

arch/powerpc/mm/ioremap_64.c

···
 		return NULL;
 
 	if (slab_is_available())
-		return do_ioremap(paligned, offset, size, prot, caller);
+		return generic_ioremap_prot(addr, size, prot);
 
 	pr_warn("ioremap() called early from %pS. Use early_ioremap() instead\n", caller);
 
···
  */
 void iounmap(volatile void __iomem *token)
 {
-	void *addr;
-
 	if (!slab_is_available())
 		return;
 
-	addr = (void *)((unsigned long __force)PCI_FIX_ADDR(token) & PAGE_MASK);
-
-	if ((unsigned long)addr < ioremap_bot) {
-		pr_warn("Attempt to iounmap early bolted mapping at 0x%p\n", addr);
-		return;
-	}
-	vunmap(addr);
+	generic_iounmap(PCI_FIX_ADDR(token));
 }
 EXPORT_SYMBOL(iounmap);