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From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: linux-pci@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Russell King <linux@armlinux.org.uk>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Pratyush Anand <pratyush.anand@gmail.com>,
	Jingoo Han <jingoohan1@gmail.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Mingkai Hu <mingkai.hu@freescale.com>,
	John Garry <john.garry@huawei.com>,
	Tanmay Inamdar <tinamdar@apm.com>,
	Murali Karicheri <m-karicheri2@ti.com>,
	Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>,
	Ray Jui <rjui@broadcom.com>, Wenrui Li <wenrui.li@rock-chips.com>,
	Shawn Lin <shawn.lin@rock-chips.com>,
	Minghuan Lian <minghuan.Lian@freescale.com>,
	Jon Mason <jonmason@broadcom.com>,
	Gabriele Paoloni <gabriele.paoloni@huawei.com>,
	Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
	Joao Pinto <Joao.Pinto@synopsys.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Michal Simek <michal.simek@xilinx.com>,
	Stanimir Varbanov <svarbanov@mm-sol.com>,
	Zhou Wang <wangzhou1@hisilicon.com>,
	Roy Zang <tie-fei.zang@freescale.com>,
	"Luis R. Rodriguez" <mcgrof@kernel.org>
Subject: [PATCH v4 03/21] ARM64: implement pci_remap_cfgspace() interface
Date: Wed, 19 Apr 2017 17:48:52 +0100	[thread overview]
Message-ID: <20170419164913.19674-4-lorenzo.pieralisi@arm.com> (raw)
In-Reply-To: <20170419164913.19674-1-lorenzo.pieralisi@arm.com>

The PCI bus specifications (rev 3.0, 3.2.5 "Transaction Ordering
and Posting") defines rules for PCI configuration space transactions
ordering and posting, that state that configuration writes
are non-posted transactions.

This rule is reinforced by the ARM v8 architecture reference manual
(issue A.k, Early Write Acknowledgment) that explicitly recommends
that No Early Write Acknowledgment attribute should be used to map
PCI configuration (write) transactions.

Current ioremap interface on ARM64 implements mapping functions
where the Early Write Acknowledgment hint is enabled, so they
cannot be used to map PCI configuration space in a PCI specs
compliant way.

Implement an ARM64 specific pci_remap_cfgspace() interface
that allows to map PCI config region with nGnRnE attributes, providing
a remap function that complies with PCI specifications and the ARMv8
architecture reference manual recommendations.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/include/asm/io.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 0c00c87..7a03250 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -173,6 +173,16 @@ extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size);
 #define iounmap				__iounmap
 
 /*
+ * PCI configuration space mapping function.
+ *
+ * PCI specifications disallows posted write configuration transactions.
+ * Add an arch specific pci_remap_cfgspace definition that is implemented
+ * through nGnRnE device memory attribute as recommended by the ARM v8
+ * Architecture reference manual Issue A.k B2.8.2 "Device memory".
+ */
+#define pci_remap_cfgspace(addr, size) __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRnE))
+
+/*
  * io{read,write}{16,32,64}be() macros
  */
 #define ioread16be(p)		({ __u16 __v = be16_to_cpu((__force __be16)__raw_readw(p)); __iormb(); __v; })
-- 
2.10.0

  parent reply	other threads:[~2017-04-19 16:56 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-19 16:48 [PATCH v4 00/21] PCI: fix config space memory mappings Lorenzo Pieralisi
2017-04-19 16:48 ` [PATCH v4 01/21] PCI: remove __weak tag from pci_remap_iospace() Lorenzo Pieralisi
2017-04-19 16:48 ` [PATCH v4 02/21] linux/io.h: add PCI config space remap interface Lorenzo Pieralisi
2017-04-20 10:51   ` Lorenzo Pieralisi
2017-04-20 13:12     ` Bjorn Helgaas
2017-04-19 16:48 ` Lorenzo Pieralisi [this message]
2017-04-20 10:33   ` [PATCH v4 03/21] ARM64: implement pci_remap_cfgspace() interface Catalin Marinas
2017-04-19 16:48 ` [PATCH v4 04/21] ARM: " Lorenzo Pieralisi
2017-04-19 16:48 ` [PATCH v4 05/21] lib: fix Devres devm_ioremap_* offset parameter kerneldoc description Lorenzo Pieralisi
2017-04-28 21:20   ` Tejun Heo
2017-04-19 16:48 ` [PATCH v4 06/21] PCI: implement Devres interface to map PCI config space Lorenzo Pieralisi
2017-04-19 16:48 ` [PATCH v4 07/21] PCI: ECAM: use pci_remap_cfgspace() to map config region Lorenzo Pieralisi
2017-04-19 16:48 ` [PATCH v4 08/21] PCI: xilinx: update PCI config space remap function Lorenzo Pieralisi
2017-04-19 16:48 ` [PATCH v4 09/21] PCI: xilinx-nwl: " Lorenzo Pieralisi
2017-04-19 16:48 ` [PATCH v4 10/21] PCI: spear13xx: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 11/21] PCI: rockchip: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 12/21] PCI: qcom: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 13/21] PCI: iproc-platform: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 14/21] PCI: designware: " Lorenzo Pieralisi
2017-04-21 22:02   ` Jingoo Han
2017-04-19 16:49 ` [PATCH v4 15/21] PCI: armada8k: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 16/21] PCI: xgene: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 17/21] PCI: tegra: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 18/21] PCI: hisi: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 19/21] PCI: layerscape: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 20/21] PCI: keystone-dw: " Lorenzo Pieralisi
2017-04-19 16:49 ` [PATCH v4 21/21] PCI: versatile: " Lorenzo Pieralisi
2017-04-20 13:25 ` [PATCH v4 00/21] PCI: fix config space memory mappings Bjorn Helgaas
2017-04-25  6:40 ` Jon Masters
2017-04-25 16:20   ` Jingoo Han
2017-04-25 18:31     ` Khuong Dinh
2017-04-26 10:53   ` Dongdong Liu
2017-04-26 17:24     ` Jingoo Han
2017-04-27  1:46       ` Dongdong Liu
2017-04-27 16:42         ` Khuong Dinh

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