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Subject[PATCH 2/2] PCI: Do not call pci_enable_resource when specifying PCI_PROBE_ONLY
Date
When using PCI_PROBE_ONLY, Linux does not assign resource to PCI devices.
This causes error when calling the pci_enable_resources function, and not
allowing driver to set the PCI_COMMAND_IO and PCI_COMMAND_MEMORY flag in
the config space of endpoint device since it checks if the resource parent
is set.

This patch adds the check in driver/pci/pci.c to avoid redundant
arch-specific code. For example, it was in arch/arm/kernel/bios32.c and
also needed in the arch/arm64/kernel/pci.c.

This should not affect other architecture since most of them either
override the weak version of pcibios_enable_device()
or does not set PCI_PROBE_ONLY.

Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Catalin Marinas <Catalin.Marinas@arm.com>
Cc: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>

---
NOTE:
Alpha seems to be the only arch that dooes not define pcibios_enable_device()
and also set PCI_PROBE_ONLY flag. I am not sure if this would cause any issues.
I might need help testing on Alpha.

arch/arm/kernel/bios32.c | 12 ------------
drivers/pci/pci.c | 3 +++
2 files changed, 3 insertions(+), 12 deletions(-)

diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
index a4effd6..091f508 100644
--- a/arch/arm/kernel/bios32.c
+++ b/arch/arm/kernel/bios32.c
@@ -607,18 +607,6 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
return start;
}

-/**
- * pcibios_enable_device - Enable I/O and memory.
- * @dev: PCI device to be enabled
- */
-int pcibios_enable_device(struct pci_dev *dev, int mask)
-{
- if (pci_has_flag(PCI_PROBE_ONLY))
- return 0;
-
- return pci_enable_resources(dev, mask);
-}
-
int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
enum pci_mmap_state mmap_state, int write_combine)
{
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e9d4fd8..1748f95 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1187,6 +1187,9 @@ EXPORT_SYMBOL_GPL(pci_load_and_free_saved_state);

int __weak pcibios_enable_device(struct pci_dev *dev, int bars)
{
+ if (pci_has_flag(PCI_PROBE_ONLY))
+ return 0;
+
return pci_enable_resources(dev, bars);
}

--
2.1.0


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