Re: [PATCH v2 03/24] PCI: Unify PCI error response checking

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 and
RESPONSE_IS_PCI_ERROR() to check the error response during hardware
read.

These definitions make error checks consistent and easier to find.

Signed-off-by: Naveen Naidu <redacted>
---
 drivers/pci/access.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index b3b2006ed1d2..03712866c818 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c

@@ -417,10 +417,10 @@ int pcie_capability_read_word(struct pci_dev *dev, int pos, u16 *val)
 		ret = pci_read_config_word(dev, pci_pcie_cap(dev) + pos, val);
 		/*
 		 * Reset *val to 0 if pci_read_config_word() fails, it may
-		 * have been written as 0xFFFF if hardware error happens
-		 * during pci_read_config_word().
+		 * have been written as 0xFFFF (PCI_ERROR_RESPONSE) if hardware error
+		 * happens during pci_read_config_word().
 		 */
-		if (ret)
+		if (RESPONSE_IS_PCI_ERROR(val))

 			*val = 0;
 		return ret;
 	}

@@ -452,10 +452,10 @@ int pcie_capability_read_dword(struct pci_dev *dev, int pos, u32 *val)
 		ret = pci_read_config_dword(dev, pci_pcie_cap(dev) + pos, val);
 		/*
 		 * Reset *val to 0 if pci_read_config_dword() fails, it may
-		 * have been written as 0xFFFFFFFF if hardware error happens
-		 * during pci_read_config_dword().
+		 * have been written as 0xFFFFFFFF (PCI_ERROR_RESPONSE) if hardware
+		 * error happens during pci_read_config_dword().
 		 */
-		if (ret)
+		if (RESPONSE_IS_PCI_ERROR(val))
 			*val = 0;
 		return ret;
 	}

@@ -529,7 +529,7 @@ EXPORT_SYMBOL(pcie_capability_clear_and_set_dword);
 int pci_read_config_byte(const struct pci_dev *dev, int where, u8 *val)
 {
 	if (pci_dev_is_disconnected(dev)) {
-		*val = ~0;
+		SET_PCI_ERROR_RESPONSE(val);
 		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 	return pci_bus_read_config_byte(dev->bus, dev->devfn, where, val);

@@ -539,7 +539,7 @@ EXPORT_SYMBOL(pci_read_config_byte);
 int pci_read_config_word(const struct pci_dev *dev, int where, u16 *val)
 {
 	if (pci_dev_is_disconnected(dev)) {
-		*val = ~0;
+		SET_PCI_ERROR_RESPONSE(val);
 		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 	return pci_bus_read_config_word(dev->bus, dev->devfn, where, val);

@@ -550,7 +550,7 @@ int pci_read_config_dword(const struct pci_dev *dev, int where,
 					u32 *val)
 {
 	if (pci_dev_is_disconnected(dev)) {
-		*val = ~0;
+		SET_PCI_ERROR_RESPONSE(val);
 		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 	return pci_bus_read_config_dword(dev->bus, dev->devfn, where, val);

-- 
2.25.1