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[PATCH v3 21/32] powerpc: include default ioremap_nopost() implementation

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The PCI specifications (Rev 3.0, 3.2.5 "Transaction Ordering and Posting")
mandate non-posted configuration transactions. As further highlighted in
the PCIe specifications (4.0 - Rev0.3, "Ordering Considerations for the
Enhanced Configuration Access Mechanism"), through ECAM and
ECAM-derivative configuration mechanism, the memory mapped transactions
from the host CPU into Configuration Requests on the PCI express fabric
may create ordering problems for software because writes to memory
address are typically posted transactions (unless the architecture can
enforce through virtual address mapping non-posted write transactions
behaviour) but writes to Configuration Space are not posted on the PCI
express fabric.

Include the asm-generic ioremap_nopost() implementation (currently
falling back to ioremap_nocache()) to provide a non-posted writes
ioremap interface to kernel subsystems.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
---
 arch/powerpc/include/asm/io.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index 5ed2924..6dcd0e2 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -757,6 +757,7 @@ extern void __iomem *ioremap_prot(phys_addr_t address, unsigned long size,
 extern void __iomem *ioremap_wc(phys_addr_t address, unsigned long size);
 #define ioremap_nocache(addr, size)	ioremap((addr), (size))
 #define ioremap_uc(addr, size)		ioremap((addr), (size))
+#include <asm-generic/ioremap-nopost.h>
 
 extern void iounmap(volatile void __iomem *addr);
 
-- 
2.10.0

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[PATCH v3 21/32] powerpc: include default ioremap_nopost() implementation Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2017-04-11 14:40 +0200
  Re: [PATCH v3 21/32] powerpc: include default ioremap_nopost()  implementation Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2017-04-11 15:50 +0200
    Re: [PATCH v3 21/32] powerpc: include default ioremap_nopost()  implementation Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2017-04-11 16:30 +0200
      Re: [PATCH v3 21/32] powerpc: include default ioremap_nopost()  implementation Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2017-04-12 01:20 +0200
        Re: [PATCH v3 21/32] powerpc: include default ioremap_nopost() implementation Michael Ellerman <mpe@ellerman.id.au> - 2017-04-13 05:40 +0200

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