1 files changed, 309 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/85xx/socrates_fpga_pic.c b/arch/powerpc/platforms/85xx/socrates_fpga_pic.c
new file mode 100644
index 000000000..199a137c0
--- /dev/null
+++ b/arch/powerpc/platforms/85xx/socrates_fpga_pic.c
@@ -0,0 +1,309 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Copyright (C) 2008 Ilya Yanok, Emcraft Systems
+ */
+
+#include <linux/irq.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/io.h>
+
+/*
+ * The FPGA supports 9 interrupt sources, which can be routed to 3
+ * interrupt request lines of the MPIC. The line to be used can be
+ * specified through the third cell of FDT property  "interrupts".
+ */
+
+#define SOCRATES_FPGA_NUM_IRQS	9
+
+#define FPGA_PIC_IRQCFG		(0x0)
+#define FPGA_PIC_IRQMASK(n)	(0x4 + 0x4 * (n))
+
+#define SOCRATES_FPGA_IRQ_MASK	((1 << SOCRATES_FPGA_NUM_IRQS) - 1)
+
+struct socrates_fpga_irq_info {
+	unsigned int irq_line;
+	int type;
+};
+
+/*
+ * Interrupt routing and type table
+ *
+ * IRQ_TYPE_NONE means the interrupt type is configurable,
+ * otherwise it's fixed to the specified value.
+ */
+static struct socrates_fpga_irq_info fpga_irqs[SOCRATES_FPGA_NUM_IRQS] = {
+	[0] = {0, IRQ_TYPE_NONE},
+	[1] = {0, IRQ_TYPE_LEVEL_HIGH},
+	[2] = {0, IRQ_TYPE_LEVEL_LOW},
+	[3] = {0, IRQ_TYPE_NONE},
+	[4] = {0, IRQ_TYPE_NONE},
+	[5] = {0, IRQ_TYPE_NONE},
+	[6] = {0, IRQ_TYPE_NONE},
+	[7] = {0, IRQ_TYPE_NONE},
+	[8] = {0, IRQ_TYPE_LEVEL_HIGH},
+};
+
+static DEFINE_RAW_SPINLOCK(socrates_fpga_pic_lock);
+
+static void __iomem *socrates_fpga_pic_iobase;
+static struct irq_domain *socrates_fpga_pic_irq_host;
+static unsigned int socrates_fpga_irqs[3];
+
+static inline uint32_t socrates_fpga_pic_read(int reg)
+{
+	return in_be32(socrates_fpga_pic_iobase + reg);
+}
+
+static inline void socrates_fpga_pic_write(int reg, uint32_t val)
+{
+	out_be32(socrates_fpga_pic_iobase + reg, val);
+}
+
+static inline unsigned int socrates_fpga_pic_get_irq(unsigned int irq)
+{
+	uint32_t cause;
+	unsigned long flags;
+	int i;
+
+	/* Check irq line routed to the MPIC */
+	for (i = 0; i < 3; i++) {
+		if (irq == socrates_fpga_irqs[i])
+			break;
+	}
+	if (i == 3)
+		return 0;
+
+	raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
+	cause = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(i));
+	raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
+	for (i = SOCRATES_FPGA_NUM_IRQS - 1; i >= 0; i--) {
+		if (cause >> (i + 16))
+			break;
+	}
+	return irq_linear_revmap(socrates_fpga_pic_irq_host,
+			(irq_hw_number_t)i);
+}
+
+static void socrates_fpga_pic_cascade(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	unsigned int irq = irq_desc_get_irq(desc);
+	unsigned int cascade_irq;
+
+	/*
+	 * See if we actually have an interrupt, call generic handling code if
+	 * we do.
+	 */
+	cascade_irq = socrates_fpga_pic_get_irq(irq);
+
+	if (cascade_irq)
+		generic_handle_irq(cascade_irq);
+	chip->irq_eoi(&desc->irq_data);
+}
+
+static void socrates_fpga_pic_ack(struct irq_data *d)
+{
+	unsigned long flags;
+	unsigned int irq_line, hwirq = irqd_to_hwirq(d);
+	uint32_t mask;
+
+	irq_line = fpga_irqs[hwirq].irq_line;
+	raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
+	mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
+		& SOCRATES_FPGA_IRQ_MASK;
+	mask |= (1 << (hwirq + 16));
+	socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
+	raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
+}
+
+static void socrates_fpga_pic_mask(struct irq_data *d)
+{
+	unsigned long flags;
+	unsigned int hwirq = irqd_to_hwirq(d);
+	int irq_line;
+	u32 mask;
+
+	irq_line = fpga_irqs[hwirq].irq_line;
+	raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
+	mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
+		& SOCRATES_FPGA_IRQ_MASK;
+	mask &= ~(1 << hwirq);
+	socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
+	raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
+}
+
+static void socrates_fpga_pic_mask_ack(struct irq_data *d)
+{
+	unsigned long flags;
+	unsigned int hwirq = irqd_to_hwirq(d);
+	int irq_line;
+	u32 mask;
+
+	irq_line = fpga_irqs[hwirq].irq_line;
+	raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
+	mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
+		& SOCRATES_FPGA_IRQ_MASK;
+	mask &= ~(1 << hwirq);
+	mask |= (1 << (hwirq + 16));
+	socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
+	raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
+}
+
+static void socrates_fpga_pic_unmask(struct irq_data *d)
+{
+	unsigned long flags;
+	unsigned int hwirq = irqd_to_hwirq(d);
+	int irq_line;
+	u32 mask;
+
+	irq_line = fpga_irqs[hwirq].irq_line;
+	raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
+	mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
+		& SOCRATES_FPGA_IRQ_MASK;
+	mask |= (1 << hwirq);
+	socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
+	raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
+}
+
+static void socrates_fpga_pic_eoi(struct irq_data *d)
+{
+	unsigned long flags;
+	unsigned int hwirq = irqd_to_hwirq(d);
+	int irq_line;
+	u32 mask;
+
+	irq_line = fpga_irqs[hwirq].irq_line;
+	raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
+	mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
+		& SOCRATES_FPGA_IRQ_MASK;
+	mask |= (1 << (hwirq + 16));
+	socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
+	raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
+}
+
+static int socrates_fpga_pic_set_type(struct irq_data *d,
+		unsigned int flow_type)
+{
+	unsigned long flags;
+	unsigned int hwirq = irqd_to_hwirq(d);
+	int polarity;
+	u32 mask;
+
+	if (fpga_irqs[hwirq].type != IRQ_TYPE_NONE)
+		return -EINVAL;
+
+	switch (flow_type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_LEVEL_HIGH:
+		polarity = 1;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		polarity = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+	raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
+	mask = socrates_fpga_pic_read(FPGA_PIC_IRQCFG);
+	if (polarity)
+		mask |= (1 << hwirq);
+	else
+		mask &= ~(1 << hwirq);
+	socrates_fpga_pic_write(FPGA_PIC_IRQCFG, mask);
+	raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
+	return 0;
+}
+
+static struct irq_chip socrates_fpga_pic_chip = {
+	.name		= "FPGA-PIC",
+	.irq_ack	= socrates_fpga_pic_ack,
+	.irq_mask	= socrates_fpga_pic_mask,
+	.irq_mask_ack	= socrates_fpga_pic_mask_ack,
+	.irq_unmask	= socrates_fpga_pic_unmask,
+	.irq_eoi	= socrates_fpga_pic_eoi,
+	.irq_set_type	= socrates_fpga_pic_set_type,
+};
+
+static int socrates_fpga_pic_host_map(struct irq_domain *h, unsigned int virq,
+		irq_hw_number_t hwirq)
+{
+	/* All interrupts are LEVEL sensitive */
+	irq_set_status_flags(virq, IRQ_LEVEL);
+	irq_set_chip_and_handler(virq, &socrates_fpga_pic_chip,
+				 handle_fasteoi_irq);
+
+	return 0;
+}
+
+static int socrates_fpga_pic_host_xlate(struct irq_domain *h,
+		struct device_node *ct,	const u32 *intspec, unsigned int intsize,
+		irq_hw_number_t *out_hwirq, unsigned int *out_flags)
+{
+	struct socrates_fpga_irq_info *fpga_irq = &fpga_irqs[intspec[0]];
+
+	*out_hwirq = intspec[0];
+	if  (fpga_irq->type == IRQ_TYPE_NONE) {
+		/* type is configurable */
+		if (intspec[1] != IRQ_TYPE_LEVEL_LOW &&
+		    intspec[1] != IRQ_TYPE_LEVEL_HIGH) {
+			pr_warn("FPGA PIC: invalid irq type, setting default active low\n");
+			*out_flags = IRQ_TYPE_LEVEL_LOW;
+		} else {
+			*out_flags = intspec[1];
+		}
+	} else {
+		/* type is fixed */
+		*out_flags = fpga_irq->type;
+	}
+
+	/* Use specified interrupt routing */
+	if (intspec[2] <= 2)
+		fpga_irq->irq_line = intspec[2];
+	else
+		pr_warn("FPGA PIC: invalid irq routing\n");
+
+	return 0;
+}
+
+static const struct irq_domain_ops socrates_fpga_pic_host_ops = {
+	.map    = socrates_fpga_pic_host_map,
+	.xlate  = socrates_fpga_pic_host_xlate,
+};
+
+void socrates_fpga_pic_init(struct device_node *pic)
+{
+	unsigned long flags;
+	int i;
+
+	/* Setup an irq_domain structure */
+	socrates_fpga_pic_irq_host = irq_domain_add_linear(pic,
+		    SOCRATES_FPGA_NUM_IRQS, &socrates_fpga_pic_host_ops, NULL);
+	if (socrates_fpga_pic_irq_host == NULL) {
+		pr_err("FPGA PIC: Unable to allocate host\n");
+		return;
+	}
+
+	for (i = 0; i < 3; i++) {
+		socrates_fpga_irqs[i] = irq_of_parse_and_map(pic, i);
+		if (!socrates_fpga_irqs[i]) {
+			pr_warn("FPGA PIC: can't get irq%d\n", i);
+			continue;
+		}
+		irq_set_chained_handler(socrates_fpga_irqs[i],
+					socrates_fpga_pic_cascade);
+	}
+
+	socrates_fpga_pic_iobase = of_iomap(pic, 0);
+
+	raw_spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
+	socrates_fpga_pic_write(FPGA_PIC_IRQMASK(0),
+			SOCRATES_FPGA_IRQ_MASK << 16);
+	socrates_fpga_pic_write(FPGA_PIC_IRQMASK(1),
+			SOCRATES_FPGA_IRQ_MASK << 16);
+	socrates_fpga_pic_write(FPGA_PIC_IRQMASK(2),
+			SOCRATES_FPGA_IRQ_MASK << 16);
+	raw_spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
+
+	pr_info("FPGA PIC: Setting up Socrates FPGA PIC\n");
+}