[PATCH v3 1/3] PCI: Introduce pcibios_ignore_alignment_request

[Shawn Anastasio <shawn@anastas.io>]

Introduce a new pcibios function pcibios_ignore_alignment_request
which allows the PCI core to defer to platform-specific code to
determine whether or not to ignore alignment requests for PCI resources.

The existing behavior is to simply ignore alignment requests when
PCI_PROBE_ONLY is set. This is behavior is maintained by the
default implementation of pcibios_ignore_alignment_request.

Signed-off-by: Shawn Anastasio <shawn@anastas.io>
---
 drivers/pci/pci.c   | 9 +++++++--
 include/linux/pci.h | 1 +
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8abc843b1615..8207a09085d1 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5882,6 +5882,11 @@ resource_size_t __weak pcibios_default_alignment(void)
 	return 0;
 }
 
+int __weak pcibios_ignore_alignment_request(void)
+{
+	return pci_has_flag(PCI_PROBE_ONLY);
+}
+
 #define RESOURCE_ALIGNMENT_PARAM_SIZE COMMAND_LINE_SIZE
 static char resource_alignment_param[RESOURCE_ALIGNMENT_PARAM_SIZE] = {0};
 static DEFINE_SPINLOCK(resource_alignment_lock);
@@ -5906,9 +5911,9 @@ static resource_size_t pci_specified_resource_alignment(struct pci_dev *dev,
 	p = resource_alignment_param;
 	if (!*p && !align)
 		goto out;
-	if (pci_has_flag(PCI_PROBE_ONLY)) {
+	if (pcibios_ignore_alignment_request()) {
 		align = 0;
-		pr_info_once("PCI: Ignoring requested alignments (PCI_PROBE_ONLY)\n");
+		pr_info_once("PCI: Ignoring requested alignments\n");
 		goto out;
 	}
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 4a5a84d7bdd4..47471dcdbaf9 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1990,6 +1990,7 @@ static inline void pcibios_penalize_isa_irq(int irq, int active) {}
 int pcibios_alloc_irq(struct pci_dev *dev);
 void pcibios_free_irq(struct pci_dev *dev);
 resource_size_t pcibios_default_alignment(void);
+int pcibios_ignore_alignment_request(void);
 
 #ifdef CONFIG_HIBERNATE_CALLBACKS
 extern struct dev_pm_ops pcibios_pm_ops;
-- 
2.20.1