sh: Inhibit mapping PCI apertures through page tables.

Inhibit mapping through page tables in __ioremap() for PCI memory
apertures on SH7751 and SH7780-style PCI controllers, translation is
not possible for these areas. For other users that map a small window
in P1/P2 space, ioremap() traps that already, and should never make
it to __ioremap().

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 25 insertions, 12 deletions

diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c
index 7377a8a8e161..d439336d2e18 100644
--- a/arch/sh/drivers/pci/pci.c
+++ b/arch/sh/drivers/pci/pci.c
@@ -195,7 +195,7 @@ void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
         unsigned long len = pci_resource_len(dev, bar);
         unsigned long flags = pci_resource_flags(dev, bar);
 
-        if (!len || !start)
+        if (unlikely(!len || !start))
                 return NULL;
         if (maxlen && len > maxlen)
                 len = maxlen;
@@ -204,18 +204,16 @@ void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
          * Presently the IORESOURCE_MEM case is a bit special, most
          * SH7751 style PCI controllers have PCI memory at a fixed
          * location in the address space where no remapping is desired
-         * (traditionally at 0xfd000000). Once this changes, the
-         * IORESOURCE_MEM case will have to switch to using ioremap() and
-         * more care will have to be taken to inhibit page table mapping
-         * for legacy cores.
-         *
-         * For now everything wraps to ioport_map(), since boards that
-         * have PCI will be able to check the address range properly on
-         * their own.
-         *                      -- PFM.
+         * (typically at 0xfd000000, but is_pci_memaddr() will know
+         * best). With the IORESOURCE_MEM case more care has to be taken
+         * to inhibit page table mapping for legacy cores, but this is
+         * punted off to __ioremap().
+         *                                      -- PFM.
          */
-        if (flags & (IORESOURCE_IO | IORESOURCE_MEM))
+        if (flags & IORESOURCE_IO)
                 return ioport_map(start, len);
+        if (flags & IORESOURCE_MEM)
+                return ioremap(start, len);
 
         return NULL;
 }
diff --git a/arch/sh/mm/ioremap.c b/arch/sh/mm/ioremap.c
index 96fa4a999e2a..a9fe80cfc233 100644
--- a/arch/sh/mm/ioremap.c
+++ b/arch/sh/mm/ioremap.c
@@ -15,6 +15,7 @@
 #include <linux/vmalloc.h>
 #include <linux/module.h>
 #include <linux/mm.h>
+#include <linux/pci.h>
 #include <asm/io.h>
 #include <asm/page.h>
 #include <asm/pgalloc.h>
@@ -135,6 +136,20 @@ void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
                 return (void __iomem *)phys_to_virt(phys_addr);
 
         /*
+         * If we're on an SH7751 or SH7780 PCI controller, PCI memory is
+         * mapped at the end of the address space (typically 0xfd000000)
+         * in a non-translatable area, so mapping through page tables for
+         * this area is not only pointless, but also fundamentally
+         * broken. Just return the physical address instead.
+         *
+         * For boards that map a small PCI memory aperture somewhere in
+         * P1/P2 space, ioremap() will already do the right thing,
+         * and we'll never get this far.
+         */
+        if (is_pci_memaddr(phys_addr) && is_pci_memaddr(last_addr))
+                return (void __iomem *)phys_addr;
+
+        /*
          * Don't allow anybody to remap normal RAM that we're using..
          */
         if (phys_addr < virt_to_phys(high_memory))
@@ -192,7 +207,7 @@ void __iounmap(void __iomem *addr)
         unsigned long vaddr = (unsigned long __force)addr;
         struct vm_struct *p;
 
-        if (PXSEG(vaddr) < P3SEG)
+        if (PXSEG(vaddr) < P3SEG || is_pci_memaddr(vaddr))
                 return;
 
 #ifdef CONFIG_32BIT