powerpc: add an ioremap_phb helper

Factor code shared between pci_64 and electra_cf into a ioremap_pbh helper
that follows the normal ioremap semantics, and returns a useful __iomem
pointer.  Note that it opencodes __ioremap_at as we know from the callers
the slab is available.  Switch pci_64 to also store the result as __iomem
pointer, and unmap the result using iounmap instead of force casting and
using vmalloc APIs.

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/20200414131348.444715-7-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 35 insertions, 18 deletions

diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index f83d1f69b1dd..2a976314f169 100644
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -109,23 +109,46 @@ int pcibios_unmap_io_space(struct pci_bus *bus)
 	/* Get the host bridge */
 	hose = pci_bus_to_host(bus);
 
-	/* Check if we have IOs allocated */
-	if (hose->io_base_alloc == NULL)
-		return 0;
-
 	pr_debug("IO unmapping for PHB %pOF\n", hose->dn);
 	pr_debug("  alloc=0x%p\n", hose->io_base_alloc);
 
-	/* This is a PHB, we fully unmap the IO area */
-	vunmap(hose->io_base_alloc);
-
+	iounmap(hose->io_base_alloc);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(pcibios_unmap_io_space);
 
-static int pcibios_map_phb_io_space(struct pci_controller *hose)
+void __iomem *ioremap_phb(phys_addr_t paddr, unsigned long size)
 {
 	struct vm_struct *area;
+	unsigned long addr;
+
+	WARN_ON_ONCE(paddr & ~PAGE_MASK);
+	WARN_ON_ONCE(size & ~PAGE_MASK);
+
+	/*
+	 * Let's allocate some IO space for that guy. We don't pass VM_IOREMAP
+	 * because we don't care about alignment tricks that the core does in
+	 * that case.  Maybe we should due to stupid card with incomplete
+	 * address decoding but I'd rather not deal with those outside of the
+	 * reserved 64K legacy region.
+	 */
+	area = __get_vm_area(size, 0, PHB_IO_BASE, PHB_IO_END);
+	if (!area)
+		return NULL;
+
+	addr = (unsigned long)area->addr;
+	if (ioremap_page_range(addr, addr + size, paddr,
+			pgprot_noncached(PAGE_KERNEL))) {
+		unmap_kernel_range(addr, size);
+		return NULL;
+	}
+
+	return (void __iomem *)addr;
+}
+EXPORT_SYMBOL_GPL(ioremap_phb);
+
+static int pcibios_map_phb_io_space(struct pci_controller *hose)
+{
 	unsigned long phys_page;
 	unsigned long size_page;
 	unsigned long io_virt_offset;
@@ -146,12 +169,11 @@ static int pcibios_map_phb_io_space(struct pci_controller *hose)
 	 * with incomplete address decoding but I'd rather not deal with
 	 * those outside of the reserved 64K legacy region.
 	 */
-	area = __get_vm_area(size_page, 0, PHB_IO_BASE, PHB_IO_END);
-	if (area == NULL)
+	hose->io_base_alloc = ioremap_phb(phys_page, size_page);
+	if (!hose->io_base_alloc)
 		return -ENOMEM;
-	hose->io_base_alloc = area->addr;
-	hose->io_base_virt = (void __iomem *)(area->addr +
-					      hose->io_base_phys - phys_page);
+	hose->io_base_virt = hose->io_base_alloc +
+				hose->io_base_phys - phys_page;
 
 	pr_debug("IO mapping for PHB %pOF\n", hose->dn);
 	pr_debug("  phys=0x%016llx, virt=0x%p (alloc=0x%p)\n",
@@ -159,11 +181,6 @@ static int pcibios_map_phb_io_space(struct pci_controller *hose)
 	pr_debug("  size=0x%016llx (alloc=0x%016lx)\n",
 		 hose->pci_io_size, size_page);
 
-	/* Establish the mapping */
-	if (__ioremap_at(phys_page, area->addr, size_page,
-			 pgprot_noncached(PAGE_KERNEL)) == NULL)
-		return -ENOMEM;
-
 	/* Fixup hose IO resource */
 	io_virt_offset = pcibios_io_space_offset(hose);
 	hose->io_resource.start += io_virt_offset;