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, 110 insertions, 0 deletions

diff --git a/drivers/clocksource/clps711x-timer.c b/drivers/clocksource/clps711x-timer.c
new file mode 100644
index 000000000..bb0a44ada
--- /dev/null
+++ b/drivers/clocksource/clps711x-timer.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Cirrus Logic CLPS711X clocksource driver
+ *
+ *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
+ */
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/clocksource.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/sched_clock.h>
+#include <linux/slab.h>
+
+enum {
+	CLPS711X_CLKSRC_CLOCKSOURCE,
+	CLPS711X_CLKSRC_CLOCKEVENT,
+};
+
+static void __iomem *tcd;
+
+static u64 notrace clps711x_sched_clock_read(void)
+{
+	return ~readw(tcd);
+}
+
+static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base)
+{
+	unsigned long rate = clk_get_rate(clock);
+
+	tcd = base;
+
+	clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16,
+			      clocksource_mmio_readw_down);
+
+	sched_clock_register(clps711x_sched_clock_read, 16, rate);
+}
+
+static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base,
+					unsigned int irq)
+{
+	struct clock_event_device *clkevt;
+	unsigned long rate;
+
+	clkevt = kzalloc_obj(*clkevt);
+	if (!clkevt)
+		return -ENOMEM;
+
+	rate = clk_get_rate(clock);
+
+	/* Set Timer prescaler */
+	writew(DIV_ROUND_CLOSEST(rate, HZ), base);
+
+	clkevt->name = "clps711x-clockevent";
+	clkevt->rating = 300;
+	clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP;
+	clkevt->cpumask = cpumask_of(0);
+	clockevents_config_and_register(clkevt, HZ, 0, 0);
+
+	return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER,
+			   "clps711x-timer", clkevt);
+}
+
+static int __init clps711x_timer_init(struct device_node *np)
+{
+	unsigned int irq = irq_of_parse_and_map(np, 0);
+	struct clk *clock = of_clk_get(np, 0);
+	void __iomem *base = of_iomap(np, 0);
+	int ret = 0;
+
+	if (!base)
+		return -ENOMEM;
+	if (!irq) {
+		ret = -EINVAL;
+		goto unmap_io;
+	}
+	if (IS_ERR(clock)) {
+		ret = PTR_ERR(clock);
+		goto unmap_io;
+	}
+
+	switch (of_alias_get_id(np, "timer")) {
+	case CLPS711X_CLKSRC_CLOCKSOURCE:
+		clps711x_clksrc_init(clock, base);
+		break;
+	case CLPS711X_CLKSRC_CLOCKEVENT:
+		ret =  _clps711x_clkevt_init(clock, base, irq);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+unmap_io:
+	iounmap(base);
+	return ret;
+}
+TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init);