PCI: Add pci_irq_type() to query the allocated interrupt typegrafted

Add a helper that returns PCI_IRQ_MSIX, PCI_IRQ_MSI, or PCI_IRQ_INTX
based on the interrupt type the PCI core selected after
pci_alloc_irq_vectors().

Several drivers already open-code this check against pdev->msix_enabled
and pdev->msi_enabled, or even open code this helper [1].

A common helper avoids the duplication and keeps drivers from accessing
the bitfield directly (see also [2]).

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Link: https://elixir.bootlin.com/linux/v7.1/source/drivers/net/ethernet/aquantia/atlantic/aq_pci_func.c#L196 [1]
Inspired-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/all/DKKG2QM3YJYB.Z2H2B2UXJ75N@kernel.org/ [2]
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260813165234.620555-5-dakr@kernel.org
[ Add missing pci_irq_type() stub for CONFIG_PCI=n. ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/sound/firewire/cmp.h b/sound/firewire/cmp.h
new file mode 100644
index 000000000..66fc08b74
--- /dev/null
+++ b/sound/firewire/cmp.h
@@ -0,0 +1,52 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef SOUND_FIREWIRE_CMP_H_INCLUDED
+#define SOUND_FIREWIRE_CMP_H_INCLUDED
+
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include "iso-resources.h"
+
+struct fw_unit;
+
+enum cmp_direction {
+	CMP_INPUT = 0,
+	CMP_OUTPUT,
+};
+
+/**
+ * struct cmp_connection - manages an isochronous connection to a device
+ * @speed: the connection's actual speed
+ *
+ * This structure manages (using CMP) an isochronous stream between the local
+ * computer and a device's input plug (iPCR) and output plug (oPCR).
+ *
+ * There is no corresponding oPCR created on the local computer, so it is not
+ * possible to overlay connections on top of this one.
+ */
+struct cmp_connection {
+	int speed;
+	/* private: */
+	bool connected;
+	struct mutex mutex;
+	struct fw_iso_resources resources;
+	__be32 last_pcr_value;
+	unsigned int pcr_index;
+	unsigned int max_speed;
+	enum cmp_direction direction;
+};
+
+int cmp_connection_init(struct cmp_connection *connection,
+			struct fw_unit *unit,
+			enum cmp_direction direction,
+			unsigned int pcr_index);
+int cmp_connection_check_used(struct cmp_connection *connection, bool *used);
+void cmp_connection_destroy(struct cmp_connection *connection);
+
+int cmp_connection_reserve(struct cmp_connection *connection,
+			   unsigned int max_payload);
+void cmp_connection_release(struct cmp_connection *connection);
+
+int cmp_connection_establish(struct cmp_connection *connection);
+void cmp_connection_break(struct cmp_connection *connection);
+
+#endif