[POWERPC] Allow hooking of PCI MMIO & PIO accessors on 64 bits

This patch reworks the way iSeries hooks on PCI IO operations (both MMIO
and PIO) and provides a generic way for other platforms to do so (we
have need to do that for various other platforms).

While reworking the IO ops, I ended up doing some spring cleaning in
io.h and eeh.h which I might want to split into 2 or 3 patches (among
others, eeh.h had a lot of useless stuff in it).

A side effect is that EEH for PIO should work now (it used to pass IO
ports down to the eeh address check functions which is bogus).

Also, new are MMIO "repeat" ops, which other archs like ARM already had,
and that we have too now: readsb, readsw, readsl, writesb, writesw,
writesl.

In the long run, I might also make EEH use the hooks instead
of wrapping at the toplevel, which would make things even cleaner and
relegate EEH completely in platforms/iseries, but we have to measure the
performance impact there (though it's really only on MMIO reads)

Since I also need to hook on ioremap, I shuffled the functions a bit
there. I introduced ioremap_flags() to use by drivers who want to pass
explicit flags to ioremap (and it can be hooked). The old __ioremap() is
still there as a low level and cannot be hooked, thus drivers who use it
should migrate unless they know they want the low level version.

The patch "arch provides generic iomap missing accessors" (should be
number 4 in this series) is a pre-requisite to provide full iomap
API support with this patch.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/Kconfig

@@ -394,6 +394,7 @@ config PPC_PSERIES
 config PPC_ISERIES
 	bool "IBM Legacy iSeries"
 	depends on PPC_MULTIPLATFORM && PPC64
+	select PPC_INDIRECT_IO
 
 config PPC_CHRP
 	bool "Common Hardware Reference Platform (CHRP) based machines"
@@ -548,6 +549,15 @@ config PPC_970_NAP
 	bool
 	default n
 
+config PPC_INDIRECT_IO
+	bool
+	select GENERIC_IOMAP
+	default n
+
+config GENERIC_IOMAP
+	bool
+	default n
+
 source "drivers/cpufreq/Kconfig"
 
 config CPU_FREQ_PMAC

arch/powerpc/kernel/Makefile

@@ -62,7 +62,7 @@ obj-$(CONFIG_PPC_UDBG_16550)	+= legacy_serial.o udbg_16550.o
 module-$(CONFIG_PPC64)		+= module_64.o
 obj-$(CONFIG_MODULES)		+= $(module-y)
 
-pci64-$(CONFIG_PPC64)		+= pci_64.o pci_dn.o iomap.o
+pci64-$(CONFIG_PPC64)		+= pci_64.o pci_dn.o
 pci32-$(CONFIG_PPC32)		:= pci_32.o
 obj-$(CONFIG_PCI)		+= $(pci64-y) $(pci32-y)
 kexec-$(CONFIG_PPC64)		:= machine_kexec_64.o
@@ -71,6 +71,10 @@ obj-$(CONFIG_KEXEC)		+= machine_kexec.o crash.o $(kexec-y)
 obj-$(CONFIG_AUDIT)		+= audit.o
 obj64-$(CONFIG_AUDIT)		+= compat_audit.o
 
+ifneq ($(CONFIG_PPC_INDIRECT_IO),y)
+pci64-$(CONFIG_PPC64)		+= iomap.o
+endif
+
 ifeq ($(CONFIG_PPC_ISERIES),y)
 $(obj)/head_64.o: $(obj)/lparmap.s
 AFLAGS_head_64.o += -I$(obj)

arch/powerpc/kernel/io.c

@@ -25,13 +25,11 @@
 #include <asm/firmware.h>
 #include <asm/bug.h>
 
-void _insb(volatile u8 __iomem *port, void *buf, long count)
+void _insb(const volatile u8 __iomem *port, void *buf, long count)
 {
 	u8 *tbuf = buf;
 	u8 tmp;
 
-	BUG_ON(firmware_has_feature(FW_FEATURE_ISERIES));
-
 	if (unlikely(count <= 0))
 		return;
 	asm volatile("sync");
@@ -48,8 +46,6 @@ void _outsb(volatile u8 __iomem *port, const void *buf, long count)
 {
 	const u8 *tbuf = buf;
 
-	BUG_ON(firmware_has_feature(FW_FEATURE_ISERIES));
-
 	if (unlikely(count <= 0))
 		return;
 	asm volatile("sync");
@@ -60,13 +56,11 @@ void _outsb(volatile u8 __iomem *port, const void *buf, long count)
 }
 EXPORT_SYMBOL(_outsb);
 
-void _insw_ns(volatile u16 __iomem *port, void *buf, long count)
+void _insw_ns(const volatile u16 __iomem *port, void *buf, long count)
 {
 	u16 *tbuf = buf;
 	u16 tmp;
 
-	BUG_ON(firmware_has_feature(FW_FEATURE_ISERIES));
-
 	if (unlikely(count <= 0))
 		return;
 	asm volatile("sync");
@@ -83,8 +77,6 @@ void _outsw_ns(volatile u16 __iomem *port, const void *buf, long count)
 {
 	const u16 *tbuf = buf;
 
-	BUG_ON(firmware_has_feature(FW_FEATURE_ISERIES));
-
 	if (unlikely(count <= 0))
 		return;
 	asm volatile("sync");
@@ -95,13 +87,11 @@ void _outsw_ns(volatile u16 __iomem *port, const void *buf, long count)
 }
 EXPORT_SYMBOL(_outsw_ns);
 
-void _insl_ns(volatile u32 __iomem *port, void *buf, long count)
+void _insl_ns(const volatile u32 __iomem *port, void *buf, long count)
 {
 	u32 *tbuf = buf;
 	u32 tmp;
 
-	BUG_ON(firmware_has_feature(FW_FEATURE_ISERIES));
-
 	if (unlikely(count <= 0))
 		return;
 	asm volatile("sync");
@@ -118,8 +108,6 @@ void _outsl_ns(volatile u32 __iomem *port, const void *buf, long count)
 {
 	const u32 *tbuf = buf;
 
-	BUG_ON(firmware_has_feature(FW_FEATURE_ISERIES));
-
 	if (unlikely(count <= 0))
 		return;
 	asm volatile("sync");

arch/powerpc/kernel/pci_64.c

@@ -1137,7 +1137,7 @@ int unmap_bus_range(struct pci_bus *bus)
 
 	if (get_bus_io_range(bus, &start_phys, &start_virt, &size))
 		return 1;
-	if (iounmap_explicit((void __iomem *) start_virt, size))
+	if (__iounmap_explicit((void __iomem *) start_virt, size))
 		return 1;
 
 	return 0;

arch/powerpc/kernel/setup_64.c

@@ -599,3 +599,10 @@ void __init setup_per_cpu_areas(void)
 	}
 }
 #endif
+
+
+#ifdef CONFIG_PPC_INDIRECT_IO
+struct ppc_pci_io ppc_pci_io;
+EXPORT_SYMBOL(ppc_pci_io);
+#endif /* CONFIG_PPC_INDIRECT_IO */
+

arch/powerpc/mm/pgtable_64.c

@@ -129,22 +129,12 @@ static void __iomem * __ioremap_com(unsigned long addr, unsigned long pa,
 	return (void __iomem *) (ea + (addr & ~PAGE_MASK));
 }
 
-
-void __iomem *
-ioremap(unsigned long addr, unsigned long size)
-{
-	return __ioremap(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED);
-}
-
 void __iomem * __ioremap(unsigned long addr, unsigned long size,
 			 unsigned long flags)
 {
 	unsigned long pa, ea;
 	void __iomem *ret;
 
-	if (firmware_has_feature(FW_FEATURE_ISERIES))
-		return (void __iomem *)addr;
-
 	/*
 	 * Choose an address to map it to.
 	 * Once the imalloc system is running, we use it.
@@ -178,6 +168,25 @@ void __iomem * __ioremap(unsigned long addr, unsigned long size,
 	return ret;
 }
 
+
+void __iomem * ioremap(unsigned long addr, unsigned long size)
+{
+	unsigned long flags = _PAGE_NO_CACHE | _PAGE_GUARDED;
+
+	if (ppc_md.ioremap)
+		return ppc_md.ioremap(addr, size, flags);
+	return __ioremap(addr, size, flags);
+}
+
+void __iomem * ioremap_flags(unsigned long addr, unsigned long size,
+			     unsigned long flags)
+{
+	if (ppc_md.ioremap)
+		return ppc_md.ioremap(addr, size, flags);
+	return __ioremap(addr, size, flags);
+}
+
+
 #define IS_PAGE_ALIGNED(_val) ((_val) == ((_val) & PAGE_MASK))
 
 int __ioremap_explicit(unsigned long pa, unsigned long ea,
@@ -235,13 +244,10 @@ int __ioremap_explicit(unsigned long pa, unsigned long ea,
  *
  * XXX	what about calls before mem_init_done (ie python_countermeasures())
  */
-void iounmap(volatile void __iomem *token)
+void __iounmap(void __iomem *token)
 {
 	void *addr;
 
-	if (firmware_has_feature(FW_FEATURE_ISERIES))
-		return;
-
 	if (!mem_init_done)
 		return;
 
@@ -250,6 +256,14 @@ void iounmap(volatile void __iomem *token)
 	im_free(addr);
 }
 
+void iounmap(void __iomem *token)
+{
+	if (ppc_md.iounmap)
+		ppc_md.iounmap(token);
+	else
+		__iounmap(token);
+}
+
 static int iounmap_subset_regions(unsigned long addr, unsigned long size)
 {
 	struct vm_struct *area;
@@ -268,7 +282,7 @@ static int iounmap_subset_regions(unsigned long addr, unsigned long size)
 	return 0;
 }
 
-int iounmap_explicit(volatile void __iomem *start, unsigned long size)
+int __iounmap_explicit(void __iomem *start, unsigned long size)
 {
 	struct vm_struct *area;
 	unsigned long addr;
@@ -303,8 +317,10 @@ int iounmap_explicit(volatile void __iomem *start, unsigned long size)
 }
 
 EXPORT_SYMBOL(ioremap);
+EXPORT_SYMBOL(ioremap_flags);
 EXPORT_SYMBOL(__ioremap);
 EXPORT_SYMBOL(iounmap);
+EXPORT_SYMBOL(__iounmap);
 
 void __iomem * reserve_phb_iospace(unsigned long size)
 {