Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 64 insertions, 0 deletions

diff --git a/drivers/pci/setup-irq.c b/drivers/pci/setup-irq.c
new file mode 100644
index 000000000..cc7d26b01
--- /dev/null
+++ b/drivers/pci/setup-irq.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Support routines for initializing a PCI subsystem
+ *
+ * Extruded from code written by
+ *      Dave Rusling (david.rusling@reo.mts.dec.com)
+ *      David Mosberger (davidm@cs.arizona.edu)
+ *	David Miller (davem@redhat.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/cache.h>
+#include "pci.h"
+
+void pci_assign_irq(struct pci_dev *dev)
+{
+	u8 pin;
+	u8 slot = -1;
+	int irq = 0;
+	struct pci_host_bridge *hbrg = pci_find_host_bridge(dev->bus);
+
+	if (!(hbrg->map_irq)) {
+		pci_dbg(dev, "runtime IRQ mapping not provided by arch\n");
+		return;
+	}
+
+	/*
+	 * If this device is not on the primary bus, we need to figure out
+	 * which interrupt pin it will come in on. We know which slot it
+	 * will come in on because that slot is where the bridge is. Each
+	 * time the interrupt line passes through a PCI-PCI bridge we must
+	 * apply the swizzle function.
+	 */
+	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
+	/* Cope with illegal. */
+	if (pin > 4)
+		pin = 1;
+
+	if (pin) {
+		/* Follow the chain of bridges, swizzling as we go. */
+		if (hbrg->swizzle_irq)
+			slot = (*(hbrg->swizzle_irq))(dev, &pin);
+
+		/*
+		 * If a swizzling function is not used, map_irq() must
+		 * ignore slot.
+		 */
+		irq = (*(hbrg->map_irq))(dev, slot, pin);
+		if (irq == -1)
+			irq = 0;
+	}
+	dev->irq = irq;
+
+	pci_dbg(dev, "assign IRQ: got %d\n", dev->irq);
+
+	/*
+	 * Always tell the device, so the driver knows what is the real IRQ
+	 * to use; the device does not use it.
+	 */
+	pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
+}