[PATCH 00/22] PCI: Unify PCI error response checking

[PATCH 00/22] PCI: Unify PCI error response checking

[Naveen Naidu]

An MMIO read from a PCI device that doesn't exist or doesn't respond
causes a PCI error.  There's no real data to return to satisfy the 
CPU read, so most hardware fabricates ~0 data.

This patch series adds PCI_ERROR_RESPONSE definition and other helper
defintion SET_PCI_ERROR_RESPONSE and RESPONSE_IS_PCI_ERROR and uses it
where appropriate to make these checks consistent and easier to find.

This helps unify PCI error response checking and make error check
consistent and easier to find.

Patch 1:
  - Adds the PCI_ERROR_RESPONSE and other related defintions
  - All other patches are dependent on this patch. This patch needs to
    be applied first, before the others

Patch 2 - 13
  - Uses SET_PCI_ERROR_RESPONSE() when device is not found

Patch 14 - 19
  - Uses RESPONSE_IS_PCI_ERROR() to check the reads from hardware

Patch 20 - 22
  - Edits the comments to include PCI_ERROR_RESPONSE alsong with
    0xFFFFFFFF, so that it becomes easier to grep for faulty hardware
    reads.

Thanks,
Naveen

Naveen Naidu (22):
  [PATCH 1/22] PCI: Add PCI_ERROR_RESPONSE and it's related defintions
  [PATCH 2/22] PCI: Unify PCI error response checking
  [PATCH 3/22] PCI: thunder: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 4/22] PCI: iproc: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 5/22] PCI: mediatek: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 6/22] PCI: exynos: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 7/22] PCI: histb: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 8/22] PCI: kirin: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 9/22] PCI: aardvark: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 10/22] PCI: mvebu: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 11/22] PCI: altera: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 12/22] PCI: rcar: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 13/22] PCI: rockchip: Use SET_PCI_ERROR_RESPONSE() when device not found
  [PATCH 14/22] PCI/ERR: Use RESPONSE_IS_PCI_ERROR() to check read from hardware
  [PATCH 15/22] PCI: vmd: Use RESPONSE_IS_PCI_ERROR() to check read from hardware
  [PATCH 16/22] PCI: pciehp: Use RESPONSE_IS_PCI_ERROR() to check read from hardware
  [PATCH 17/22] PCI/DPC: Use RESPONSE_IS_PCI_ERROR() to check read from hardware
  [PATCH 18/22] PCI/PME: Use RESPONSE_IS_PCI_ERROR() to check read from hardware
  [PATCH 19/22] PCI: cpqphp: Use RESPONSE_IS_PCI_ERROR() to check read from hardware
  [PATCH 20/22] PCI: keystone: Use PCI_ERROR_RESPONSE to specify hardware error
  [PATCH 21/22] PCI: hv: Use PCI_ERROR_RESPONSE to specify hardware read error
  [PATCH 22/22] PCI: xgene: Use PCI_ERROR_RESPONSE to specify hardware error

 drivers/pci/access.c                        | 22 ++++++++++-----------
 drivers/pci/controller/dwc/pci-exynos.c     |  2 +-
 drivers/pci/controller/dwc/pci-keystone.c   |  4 ++--
 drivers/pci/controller/dwc/pcie-histb.c     |  2 +-
 drivers/pci/controller/dwc/pcie-kirin.c     |  2 +-
 drivers/pci/controller/pci-aardvark.c       |  8 ++++----
 drivers/pci/controller/pci-hyperv.c         |  2 +-
 drivers/pci/controller/pci-mvebu.c          |  4 ++--
 drivers/pci/controller/pci-thunder-ecam.c   | 20 +++++++++----------
 drivers/pci/controller/pci-thunder-pem.c    |  2 +-
 drivers/pci/controller/pci-xgene.c          |  8 ++++----
 drivers/pci/controller/pcie-altera.c        |  2 +-
 drivers/pci/controller/pcie-iproc.c         |  2 +-
 drivers/pci/controller/pcie-mediatek.c      |  4 ++--
 drivers/pci/controller/pcie-rcar-host.c     |  2 +-
 drivers/pci/controller/pcie-rockchip-host.c |  2 +-
 drivers/pci/controller/vmd.c                |  2 +-
 drivers/pci/hotplug/cpqphp_ctrl.c           |  4 ++--
 drivers/pci/hotplug/pciehp_hpc.c            | 10 +++++-----
 drivers/pci/pci.c                           | 10 +++++-----
 drivers/pci/pcie/dpc.c                      |  4 ++--
 drivers/pci/pcie/pme.c                      |  4 ++--
 drivers/pci/probe.c                         | 10 +++++-----
 include/linux/pci.h                         |  9 +++++++++
 24 files changed, 75 insertions(+), 66 deletions(-)

-- 
2.25.1

[PATCH 01/22] PCI: Add PCI_ERROR_RESPONSE and it's related defintions

[Naveen Naidu]

An MMIO read from a PCI device that doesn't exist or doesn't respond
causes a PCI error.  There's no real data to return to satisfy the
CPU read, so most hardware fabricates ~0 data.

Add a PCI_ERROR_RESPONSE definition for that and use it where
appropriate to make these checks consistent and easier to find.

Also add helper definitions SET_PCI_ERROR_RESPONSE and
RESPONSE_IS_PCI_ERROR to make the code more readable.

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 include/linux/pci.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index cd8aa6fce204..928c589bb5c4 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -154,6 +154,15 @@ enum pci_interrupt_pin {
 /* The number of legacy PCI INTx interrupts */
 #define PCI_NUM_INTX	4
 
+/*
+ * Reading from a device that doesn't respond typically returns ~0.  A
+ * successful read from a device may also return ~0, so you need additional
+ * information to reliably identify errors.
+ */
+#define PCI_ERROR_RESPONSE			(~0ULL)
+#define SET_PCI_ERROR_RESPONSE(val)	(*val = ((typeof(*val)) PCI_ERROR_RESPONSE))
+#define RESPONSE_IS_PCI_ERROR(val)	(*val == ((typeof(*val)) PCI_ERROR_RESPONSE))
+
 /*
  * pci_power_t values must match the bits in the Capabilities PME_Support
  * and Control/Status PowerState fields in the Power Management capability.
-- 
2.25.1

[PATCH 06/22] PCI: exynos: Use SET_PCI_ERROR_RESPONSE() when device not found

[Naveen Naidu]

An MMIO read from a PCI device that doesn't exist or doesn't respond
causes a PCI error.  There's no real data to return to satisfy the
CPU read, so most hardware fabricates ~0 data.

Use SET_PCI_ERROR_RESPONSE() to set the error response, when a faulty
read occurs.

This helps unify PCI error response checking and make error check
consistent and easier to find.

Compile tested only.

Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
---
 drivers/pci/controller/dwc/pci-exynos.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/pci-exynos.c b/drivers/pci/controller/dwc/pci-exynos.c
index c24dab383654..1fdbef184532 100644
--- a/drivers/pci/controller/dwc/pci-exynos.c
+++ b/drivers/pci/controller/dwc/pci-exynos.c
@@ -217,7 +217,7 @@ static int exynos_pcie_rd_own_conf(struct pci_bus *bus, unsigned int devfn,
 	struct dw_pcie *pci = to_dw_pcie_from_pp(bus->sysdata);
 
 	if (PCI_SLOT(devfn)) {
-		*val = ~0;
+		SET_PCI_ERROR_RESPONSE(val);
 		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 
-- 
2.25.1