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, 32 insertions, 0 deletions

diff --git a/scripts/mod/mk_elfconfig.c b/scripts/mod/mk_elfconfig.c
new file mode 100644
index 000000000..e8cee4e4b
--- /dev/null
+++ b/scripts/mod/mk_elfconfig.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <elf.h>
+
+int
+main(int argc, char **argv)
+{
+	unsigned char ei[EI_NIDENT];
+
+	if (fread(ei, 1, EI_NIDENT, stdin) != EI_NIDENT) {
+		fprintf(stderr, "Error: input truncated\n");
+		return 1;
+	}
+	if (memcmp(ei, ELFMAG, SELFMAG) != 0) {
+		fprintf(stderr, "Error: not ELF\n");
+		return 1;
+	}
+	switch (ei[EI_CLASS]) {
+	case ELFCLASS32:
+		printf("#define KERNEL_ELFCLASS ELFCLASS32\n");
+		break;
+	case ELFCLASS64:
+		printf("#define KERNEL_ELFCLASS ELFCLASS64\n");
+		break;
+	default:
+		exit(1);
+	}
+
+	return 0;
+}