powerpc: remove __ioremap_at and __iounmap_at

These helpers are only used for remapping the ISA I/O base.  Replace the
mapping side with a remap_isa_range helper in isa-bridge.c that hard codes
all the known arguments, and just remove __iounmap_at in favour of open
coding it in the only caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-8-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/include/asm/io.h

@@ -699,10 +699,6 @@ static inline void iosync(void)
  *
  * * iounmap undoes such a mapping and can be hooked
  *
- * * __ioremap_at (and the pending __iounmap_at) are low level functions to
- *   create hand-made mappings for use only by the PCI code and cannot
- *   currently be hooked. Must be page aligned.
- *
  * * __ioremap_caller is the same as above but takes an explicit caller
  *   reference rather than using __builtin_return_address(0)
  *
@@ -729,10 +725,6 @@ void __iomem *do_ioremap(phys_addr_t pa, phys_addr_t offset, unsigned long size,
 extern void __iomem *__ioremap_caller(phys_addr_t, unsigned long size,
 				      pgprot_t prot, void *caller);
 
-extern void __iomem * __ioremap_at(phys_addr_t pa, void *ea,
-				   unsigned long size, pgprot_t prot);
-extern void __iounmap_at(void *ea, unsigned long size);
-
 /*
  * When CONFIG_PPC_INDIRECT_PIO is set, we use the generic iomap implementation
  * which needs some additional definitions here. They basically allow PIO

arch/powerpc/kernel/isa-bridge.c

@@ -18,6 +18,7 @@
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/notifier.h>
+#include <linux/vmalloc.h>
 
 #include <asm/processor.h>
 #include <asm/io.h>
@@ -38,6 +39,22 @@ EXPORT_SYMBOL_GPL(isa_bridge_pcidev);
 #define ISA_SPACE_MASK 0x1
 #define ISA_SPACE_IO 0x1
 
+static void remap_isa_base(phys_addr_t pa, unsigned long size)
+{
+	WARN_ON_ONCE(ISA_IO_BASE & ~PAGE_MASK);
+	WARN_ON_ONCE(pa & ~PAGE_MASK);
+	WARN_ON_ONCE(size & ~PAGE_MASK);
+
+	if (slab_is_available()) {
+		if (ioremap_page_range(ISA_IO_BASE, ISA_IO_BASE + size, pa,
+				pgprot_noncached(PAGE_KERNEL)))
+			unmap_kernel_range(ISA_IO_BASE, size);
+	} else {
+		early_ioremap_range(ISA_IO_BASE, pa, size,
+				pgprot_noncached(PAGE_KERNEL));
+	}
+}
+
 static void pci_process_ISA_OF_ranges(struct device_node *isa_node,
 				      unsigned long phb_io_base_phys)
 {
@@ -105,15 +122,13 @@ static void pci_process_ISA_OF_ranges(struct device_node *isa_node,
 	if (size > 0x10000)
 		size = 0x10000;
 
-	__ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
+	remap_isa_base(phb_io_base_phys, size);
-		     size, pgprot_noncached(PAGE_KERNEL));
 	return;
 
 inval_range:
 	printk(KERN_ERR "no ISA IO ranges or unexpected isa range, "
 	       "mapping 64k\n");
-	__ioremap_at(phb_io_base_phys, (void *)ISA_IO_BASE,
+	remap_isa_base(phb_io_base_phys, 0x10000);
-		     0x10000, pgprot_noncached(PAGE_KERNEL));
 }
 
 
@@ -248,8 +263,7 @@ void __init isa_bridge_init_non_pci(struct device_node *np)
 	 * and map it
 	 */
 	isa_io_base = ISA_IO_BASE;
-	__ioremap_at(pbase, (void *)ISA_IO_BASE,
+	remap_isa_base(pbase, size);
-		     size, pgprot_noncached(PAGE_KERNEL));
 
 	pr_debug("ISA: Non-PCI bridge is %pOF\n", np);
 }
@@ -297,7 +311,7 @@ static void isa_bridge_remove(void)
 	isa_bridge_pcidev = NULL;
 
 	/* Unmap the ISA area */
-	__iounmap_at((void *)ISA_IO_BASE, 0x10000);
+	unmap_kernel_range(ISA_IO_BASE, 0x10000);
 }
 
 /**

arch/powerpc/mm/ioremap_64.c

@@ -4,56 +4,6 @@
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 
-/**
- * Low level function to establish the page tables for an IO mapping
- */
-void __iomem *__ioremap_at(phys_addr_t pa, void *ea, unsigned long size, pgprot_t prot)
-{
-	int ret;
-	unsigned long va = (unsigned long)ea;
-
-	/* We don't support the 4K PFN hack with ioremap */
-	if (pgprot_val(prot) & H_PAGE_4K_PFN)
-		return NULL;
-
-	if ((ea + size) >= (void *)IOREMAP_END) {
-		pr_warn("Outside the supported range\n");
-		return NULL;
-	}
-
-	WARN_ON(pa & ~PAGE_MASK);
-	WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
-	WARN_ON(size & ~PAGE_MASK);
-
-	if (slab_is_available()) {
-		ret = ioremap_page_range(va, va + size, pa, prot);
-		if (ret)
-			unmap_kernel_range(va, size);
-	} else {
-		ret = early_ioremap_range(va, pa, size, prot);
-	}
-
-	if (ret)
-		return NULL;
-
-	return (void __iomem *)ea;
-}
-EXPORT_SYMBOL(__ioremap_at);
-
-/**
- * Low level function to tear down the page tables for an IO mapping. This is
- * used for mappings that are manipulated manually, like partial unmapping of
- * PCI IOs or ISA space.
- */
-void __iounmap_at(void *ea, unsigned long size)
-{
-	WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
-	WARN_ON(size & ~PAGE_MASK);
-
-	unmap_kernel_range((unsigned long)ea, size);
-}
-EXPORT_SYMBOL(__iounmap_at);
-
 void __iomem *__ioremap_caller(phys_addr_t addr, unsigned long size,
 			       pgprot_t prot, void *caller)
 {