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, 132 insertions, 0 deletions

diff --git a/drivers/reset/reset-scmi.c b/drivers/reset/reset-scmi.c
new file mode 100644
index 000000000..4335811e0
--- /dev/null
+++ b/drivers/reset/reset-scmi.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ARM System Control and Management Interface (ARM SCMI) reset driver
+ *
+ * Copyright (C) 2019-2021 ARM Ltd.
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/device.h>
+#include <linux/reset-controller.h>
+#include <linux/scmi_protocol.h>
+
+static const struct scmi_reset_proto_ops *reset_ops;
+
+/**
+ * struct scmi_reset_data - reset controller information structure
+ * @rcdev: reset controller entity
+ * @ph: ARM SCMI protocol handle used for communication with system controller
+ */
+struct scmi_reset_data {
+	struct reset_controller_dev rcdev;
+	const struct scmi_protocol_handle *ph;
+};
+
+#define to_scmi_reset_data(p)	container_of((p), struct scmi_reset_data, rcdev)
+#define to_scmi_handle(p)	(to_scmi_reset_data(p)->ph)
+
+/**
+ * scmi_reset_assert() - assert device reset
+ * @rcdev: reset controller entity
+ * @id: ID of the reset to be asserted
+ *
+ * This function implements the reset driver op to assert a device's reset
+ * using the ARM SCMI protocol.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int
+scmi_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev);
+
+	return reset_ops->assert(ph, id);
+}
+
+/**
+ * scmi_reset_deassert() - deassert device reset
+ * @rcdev: reset controller entity
+ * @id: ID of the reset to be deasserted
+ *
+ * This function implements the reset driver op to deassert a device's reset
+ * using the ARM SCMI protocol.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int
+scmi_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev);
+
+	return reset_ops->deassert(ph, id);
+}
+
+/**
+ * scmi_reset_reset() - reset the device
+ * @rcdev: reset controller entity
+ * @id: ID of the reset signal to be reset(assert + deassert)
+ *
+ * This function implements the reset driver op to trigger a device's
+ * reset signal using the ARM SCMI protocol.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int
+scmi_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
+{
+	const struct scmi_protocol_handle *ph = to_scmi_handle(rcdev);
+
+	return reset_ops->reset(ph, id);
+}
+
+static const struct reset_control_ops scmi_reset_ops = {
+	.assert		= scmi_reset_assert,
+	.deassert	= scmi_reset_deassert,
+	.reset		= scmi_reset_reset,
+};
+
+static int scmi_reset_probe(struct scmi_device *sdev)
+{
+	struct scmi_reset_data *data;
+	struct device *dev = &sdev->dev;
+	struct device_node *np = dev->of_node;
+	const struct scmi_handle *handle = sdev->handle;
+	struct scmi_protocol_handle *ph;
+
+	if (!handle)
+		return -ENODEV;
+
+	reset_ops = handle->devm_protocol_get(sdev, SCMI_PROTOCOL_RESET, &ph);
+	if (IS_ERR(reset_ops))
+		return PTR_ERR(reset_ops);
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->rcdev.ops = &scmi_reset_ops;
+	data->rcdev.owner = THIS_MODULE;
+	data->rcdev.of_node = np;
+	data->rcdev.nr_resets = reset_ops->num_domains_get(ph);
+	data->ph = ph;
+
+	return devm_reset_controller_register(dev, &data->rcdev);
+}
+
+static const struct scmi_device_id scmi_id_table[] = {
+	{ SCMI_PROTOCOL_RESET, "reset" },
+	{ },
+};
+MODULE_DEVICE_TABLE(scmi, scmi_id_table);
+
+static struct scmi_driver scmi_reset_driver = {
+	.name = "scmi-reset",
+	.probe = scmi_reset_probe,
+	.id_table = scmi_id_table,
+};
+module_scmi_driver(scmi_reset_driver);
+
+MODULE_AUTHOR("Sudeep Holla <sudeep.holla@arm.com>");
+MODULE_DESCRIPTION("ARM SCMI reset controller driver");
+MODULE_LICENSE("GPL v2");