Adding upstream version 6.6.15.upstream/6.6.15

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

1 files changed, 202 insertions, 0 deletions

diff --git a/drivers/irqchip/irq-ompic.c b/drivers/irqchip/irq-ompic.c
new file mode 100644
index 0000000000..e66ef4373b
--- /dev/null
+++ b/drivers/irqchip/irq-ompic.c
@@ -0,0 +1,202 @@
+/*
+ * Open Multi-Processor Interrupt Controller driver
+ *
+ * Copyright (C) 2014 Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
+ * Copyright (C) 2017 Stafford Horne <shorne@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ *
+ * The ompic device handles IPI communication between cores in multi-core
+ * OpenRISC systems.
+ *
+ * Registers
+ *
+ * For each CPU the ompic has 2 registers. The control register for sending
+ * and acking IPIs and the status register for receiving IPIs. The register
+ * layouts are as follows:
+ *
+ *  Control register
+ *  +---------+---------+----------+---------+
+ *  | 31      | 30      | 29 .. 16 | 15 .. 0 |
+ *  ----------+---------+----------+----------
+ *  | IRQ ACK | IRQ GEN | DST CORE | DATA    |
+ *  +---------+---------+----------+---------+
+ *
+ *  Status register
+ *  +----------+-------------+----------+---------+
+ *  | 31       | 30          | 29 .. 16 | 15 .. 0 |
+ *  -----------+-------------+----------+---------+
+ *  | Reserved | IRQ Pending | SRC CORE | DATA    |
+ *  +----------+-------------+----------+---------+
+ *
+ * Architecture
+ *
+ * - The ompic generates a level interrupt to the CPU PIC when a message is
+ *   ready.  Messages are delivered via the memory bus.
+ * - The ompic does not have any interrupt input lines.
+ * - The ompic is wired to the same irq line on each core.
+ * - Devices are wired to the same irq line on each core.
+ *
+ *   +---------+                         +---------+
+ *   | CPU     |                         | CPU     |
+ *   |  Core 0 |<==\ (memory access) /==>|  Core 1 |
+ *   |  [ PIC ]|   |                 |   |  [ PIC ]|
+ *   +----^-^--+   |                 |   +----^-^--+
+ *        | |      v                 v        | |
+ *   <====|=|=================================|=|==> (memory bus)
+ *        | |      ^                  ^       | |
+ *  (ipi  | +------|---------+--------|-------|-+ (device irq)
+ *   irq  |        |         |        |       |
+ *  core0)| +------|---------|--------|-------+ (ipi irq core1)
+ *        | |      |         |        |
+ *   +----o-o-+    |    +--------+    |
+ *   | ompic  |<===/    | Device |<===/
+ *   |  IPI   |         +--------+
+ *   +--------+*
+ *
+ */
+
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/smp.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+
+#include <linux/irqchip.h>
+
+#define OMPIC_CPUBYTES		8
+#define OMPIC_CTRL(cpu)		(0x0 + (cpu * OMPIC_CPUBYTES))
+#define OMPIC_STAT(cpu)		(0x4 + (cpu * OMPIC_CPUBYTES))
+
+#define OMPIC_CTRL_IRQ_ACK	(1 << 31)
+#define OMPIC_CTRL_IRQ_GEN	(1 << 30)
+#define OMPIC_CTRL_DST(cpu)	(((cpu) & 0x3fff) << 16)
+
+#define OMPIC_STAT_IRQ_PENDING	(1 << 30)
+
+#define OMPIC_DATA(x)		((x) & 0xffff)
+
+DEFINE_PER_CPU(unsigned long, ops);
+
+static void __iomem *ompic_base;
+
+static inline u32 ompic_readreg(void __iomem *base, loff_t offset)
+{
+	return ioread32be(base + offset);
+}
+
+static void ompic_writereg(void __iomem *base, loff_t offset, u32 data)
+{
+	iowrite32be(data, base + offset);
+}
+
+static void ompic_raise_softirq(const struct cpumask *mask,
+				unsigned int ipi_msg)
+{
+	unsigned int dst_cpu;
+	unsigned int src_cpu = smp_processor_id();
+
+	for_each_cpu(dst_cpu, mask) {
+		set_bit(ipi_msg, &per_cpu(ops, dst_cpu));
+
+		/*
+		 * On OpenRISC the atomic set_bit() call implies a memory
+		 * barrier.  Otherwise we would need: smp_wmb(); paired
+		 * with the read in ompic_ipi_handler.
+		 */
+
+		ompic_writereg(ompic_base, OMPIC_CTRL(src_cpu),
+			       OMPIC_CTRL_IRQ_GEN |
+			       OMPIC_CTRL_DST(dst_cpu) |
+			       OMPIC_DATA(1));
+	}
+}
+
+static irqreturn_t ompic_ipi_handler(int irq, void *dev_id)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned long *pending_ops = &per_cpu(ops, cpu);
+	unsigned long ops;
+
+	ompic_writereg(ompic_base, OMPIC_CTRL(cpu), OMPIC_CTRL_IRQ_ACK);
+	while ((ops = xchg(pending_ops, 0)) != 0) {
+
+		/*
+		 * On OpenRISC the atomic xchg() call implies a memory
+		 * barrier.  Otherwise we may need an smp_rmb(); paired
+		 * with the write in ompic_raise_softirq.
+		 */
+
+		do {
+			unsigned long ipi_msg;
+
+			ipi_msg = __ffs(ops);
+			ops &= ~(1UL << ipi_msg);
+
+			handle_IPI(ipi_msg);
+		} while (ops);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int __init ompic_of_init(struct device_node *node,
+				struct device_node *parent)
+{
+	struct resource res;
+	int irq;
+	int ret;
+
+	/* Validate the DT */
+	if (ompic_base) {
+		pr_err("ompic: duplicate ompic's are not supported");
+		return -EEXIST;
+	}
+
+	if (of_address_to_resource(node, 0, &res)) {
+		pr_err("ompic: reg property requires an address and size");
+		return -EINVAL;
+	}
+
+	if (resource_size(&res) < (num_possible_cpus() * OMPIC_CPUBYTES)) {
+		pr_err("ompic: reg size, currently %d must be at least %d",
+			resource_size(&res),
+			(num_possible_cpus() * OMPIC_CPUBYTES));
+		return -EINVAL;
+	}
+
+	/* Setup the device */
+	ompic_base = ioremap(res.start, resource_size(&res));
+	if (!ompic_base) {
+		pr_err("ompic: unable to map registers");
+		return -ENOMEM;
+	}
+
+	irq = irq_of_parse_and_map(node, 0);
+	if (irq <= 0) {
+		pr_err("ompic: unable to parse device irq");
+		ret = -EINVAL;
+		goto out_unmap;
+	}
+
+	ret = request_irq(irq, ompic_ipi_handler, IRQF_PERCPU,
+				"ompic_ipi", NULL);
+	if (ret)
+		goto out_irq_disp;
+
+	set_smp_cross_call(ompic_raise_softirq);
+
+	return 0;
+
+out_irq_disp:
+	irq_dispose_mapping(irq);
+out_unmap:
+	iounmap(ompic_base);
+	ompic_base = NULL;
+	return ret;
+}
+IRQCHIP_DECLARE(ompic, "openrisc,ompic", ompic_of_init);