powerpc: GE Fanuc's FPGA based PIC controller on the SBC610

Support for the SBC610 VPX Single Board Computer from GE Fanuc (PowerPC MPC8641D).

A number of MPC8641D based route interrupts for on-board interrupts through
a FPGA based interrupt controller, which is chained with the
MPC8641D's mpic. This patch provides a basic driver to allow basic routing
of interrupts to the mpic.

Signed-off-by: Martyn Welch <martyn.welch@gefanuc.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

4 files changed, 294 insertions, 2 deletions

diff --git a/arch/powerpc/platforms/86xx/Makefile b/arch/powerpc/platforms/86xx/Makefile
index cb9fc8f4360..4a56ff619af 100644
--- a/arch/powerpc/platforms/86xx/Makefile
+++ b/arch/powerpc/platforms/86xx/Makefile
@@ -7,4 +7,4 @@ obj-$(CONFIG_SMP)		+= mpc86xx_smp.o
 obj-$(CONFIG_MPC8641_HPCN)	+= mpc86xx_hpcn.o
 obj-$(CONFIG_SBC8641D)		+= sbc8641d.o
 obj-$(CONFIG_MPC8610_HPCD)	+= mpc8610_hpcd.o
-obj-$(CONFIG_GEF_SBC610)	+= gef_sbc610.o
+obj-$(CONFIG_GEF_SBC610)	+= gef_sbc610.o gef_pic.o
diff --git a/arch/powerpc/platforms/86xx/gef_pic.c b/arch/powerpc/platforms/86xx/gef_pic.c
new file mode 100644
index 00000000000..50d0a2b6380
--- /dev/null
+++ b/arch/powerpc/platforms/86xx/gef_pic.c
@@ -0,0 +1,258 @@
+/*
+ * Interrupt handling for GE Fanuc's FPGA based PIC
+ *
+ * Author: Martyn Welch <martyn.welch@gefanuc.com>
+ *
+ * 2008 (c) GE Fanuc Intelligent Platforms Embedded Systems, Inc.
+ *
+ * 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.
+ */
+
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+
+#include <asm/byteorder.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/irq.h>
+
+#include "gef_pic.h"
+
+#define DEBUG
+#undef DEBUG
+
+#ifdef DEBUG
+#define DBG(fmt...) do { printk(KERN_DEBUG "gef_pic: " fmt); } while (0)
+#else
+#define DBG(fmt...) do { } while (0)
+#endif
+
+#define GEF_PIC_NUM_IRQS	32
+
+/* Interrupt Controller Interface Registers */
+#define GEF_PIC_INTR_STATUS	0x0000
+
+#define GEF_PIC_INTR_MASK(cpu)	(0x0010 + (0x4 * cpu))
+#define GEF_PIC_CPU0_INTR_MASK	GEF_PIC_INTR_MASK(0)
+#define GEF_PIC_CPU1_INTR_MASK	GEF_PIC_INTR_MASK(1)
+
+#define GEF_PIC_MCP_MASK(cpu)	(0x0018 + (0x4 * cpu))
+#define GEF_PIC_CPU0_MCP_MASK	GEF_PIC_MCP_MASK(0)
+#define GEF_PIC_CPU1_MCP_MASK	GEF_PIC_MCP_MASK(1)
+
+#define gef_irq_to_hw(virq)    ((unsigned int)irq_map[virq].hwirq)
+
+
+static DEFINE_SPINLOCK(gef_pic_lock);
+
+static void __iomem *gef_pic_irq_reg_base;
+static struct irq_host *gef_pic_irq_host;
+static int gef_pic_cascade_irq;
+
+/*
+ * Interrupt Controller Handling
+ *
+ * The interrupt controller handles interrupts for most on board interrupts,
+ * apart from PCI interrupts. For example on SBC610:
+ *
+ * 17:31 RO Reserved
+ * 16    RO PCI Express Doorbell 3 Status
+ * 15    RO PCI Express Doorbell 2 Status
+ * 14    RO PCI Express Doorbell 1 Status
+ * 13    RO PCI Express Doorbell 0 Status
+ * 12    RO Real Time Clock Interrupt Status
+ * 11    RO Temperature Interrupt Status
+ * 10    RO Temperature Critical Interrupt Status
+ * 9     RO Ethernet PHY1 Interrupt Status
+ * 8     RO Ethernet PHY3 Interrupt Status
+ * 7     RO PEX8548 Interrupt Status
+ * 6     RO Reserved
+ * 5     RO Watchdog 0 Interrupt Status
+ * 4     RO Watchdog 1 Interrupt Status
+ * 3     RO AXIS Message FIFO A Interrupt Status
+ * 2     RO AXIS Message FIFO B Interrupt Status
+ * 1     RO AXIS Message FIFO C Interrupt Status
+ * 0     RO AXIS Message FIFO D Interrupt Status
+ *
+ * Interrupts can be forwarded to one of two output lines. Nothing
+ * clever is done, so if the masks are incorrectly set, a single input
+ * interrupt could generate interrupts on both output lines!
+ *
+ * The dual lines are there to allow the chained interrupts to be easily
+ * passed into two different cores. We currently do not use this functionality
+ * in this driver.
+ *
+ * Controller can also be configured to generate Machine checks (MCP), again on
+ * two lines, to be attached to two different cores. It is suggested that these
+ * should be masked out.
+ */
+
+void gef_pic_cascade(unsigned int irq, struct irq_desc *desc)
+{
+	unsigned int cascade_irq;
+
+	/*
+	 * See if we actually have an interrupt, call generic handling code if
+	 * we do.
+	 */
+	cascade_irq = gef_pic_get_irq();
+
+	if (cascade_irq != NO_IRQ)
+		generic_handle_irq(cascade_irq);
+
+	desc->chip->eoi(irq);
+
+}
+
+static void gef_pic_mask(unsigned int virq)
+{
+	unsigned long flags;
+	unsigned int hwirq;
+	u32 mask;
+
+	hwirq = gef_irq_to_hw(virq);
+
+	spin_lock_irqsave(&gef_pic_lock, flags);
+	mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
+	mask &= ~(1 << hwirq);
+	out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask);
+	spin_unlock_irqrestore(&gef_pic_lock, flags);
+}
+
+static void gef_pic_mask_ack(unsigned int virq)
+{
+	/* Don't think we actually have to do anything to ack an interrupt,
+	 * we just need to clear down the devices interrupt and it will go away
+	 */
+	gef_pic_mask(virq);
+}
+
+static void gef_pic_unmask(unsigned int virq)
+{
+	unsigned long flags;
+	unsigned int hwirq;
+	u32 mask;
+
+	hwirq = gef_irq_to_hw(virq);
+
+	spin_lock_irqsave(&gef_pic_lock, flags);
+	mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
+	mask |= (1 << hwirq);
+	out_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0), mask);
+	spin_unlock_irqrestore(&gef_pic_lock, flags);
+}
+
+static struct irq_chip gef_pic_chip = {
+	.typename	= "gefp",
+	.mask		= gef_pic_mask,
+	.mask_ack	= gef_pic_mask_ack,
+	.unmask		= gef_pic_unmask,
+};
+
+
+/* When an interrupt is being configured, this call allows some flexibilty
+ * in deciding which irq_chip structure is used
+ */
+static int gef_pic_host_map(struct irq_host *h, unsigned int virq,
+			  irq_hw_number_t hwirq)
+{
+	/* All interrupts are LEVEL sensitive */
+	get_irq_desc(virq)->status |= IRQ_LEVEL;
+	set_irq_chip_and_handler(virq, &gef_pic_chip, handle_level_irq);
+
+	return 0;
+}
+
+static int gef_pic_host_xlate(struct irq_host *h, struct device_node *ct,
+			    u32 *intspec, unsigned int intsize,
+			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
+{
+
+	*out_hwirq = intspec[0];
+	if (intsize > 1)
+		*out_flags = intspec[1];
+	else
+		*out_flags = IRQ_TYPE_LEVEL_HIGH;
+
+	return 0;
+}
+
+static struct irq_host_ops gef_pic_host_ops = {
+	.map	= gef_pic_host_map,
+	.xlate	= gef_pic_host_xlate,
+};
+
+
+/*
+ * Initialisation of PIC, this should be called in BSP
+ */
+void __init gef_pic_init(struct device_node *np)
+{
+	unsigned long flags;
+
+	/* Map the devices registers into memory */
+	gef_pic_irq_reg_base = of_iomap(np, 0);
+
+	spin_lock_irqsave(&gef_pic_lock, flags);
+
+	/* Initialise everything as masked. */
+	out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_INTR_MASK, 0);
+	out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_INTR_MASK, 0);
+
+	out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU0_MCP_MASK, 0);
+	out_be32(gef_pic_irq_reg_base + GEF_PIC_CPU1_MCP_MASK, 0);
+
+	spin_unlock_irqrestore(&gef_pic_lock, flags);
+
+	/* Map controller */
+	gef_pic_cascade_irq = irq_of_parse_and_map(np, 0);
+	if (gef_pic_cascade_irq == NO_IRQ) {
+		printk(KERN_ERR "SBC610: failed to map cascade interrupt");
+		return;
+	}
+
+	/* Setup an irq_host structure */
+	gef_pic_irq_host = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR,
+					  GEF_PIC_NUM_IRQS,
+					  &gef_pic_host_ops, NO_IRQ);
+	if (gef_pic_irq_host == NULL)
+		return;
+
+	/* Chain with parent controller */
+	set_irq_chained_handler(gef_pic_cascade_irq, gef_pic_cascade);
+}
+
+/*
+ * This is called when we receive an interrupt with apparently comes from this
+ * chip - check, returning the highest interrupt generated or return NO_IRQ
+ */
+unsigned int gef_pic_get_irq(void)
+{
+	u32 cause, mask, active;
+	unsigned int virq = NO_IRQ;
+	int hwirq;
+
+	cause = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_STATUS);
+
+	mask = in_be32(gef_pic_irq_reg_base + GEF_PIC_INTR_MASK(0));
+
+	active = cause & mask;
+
+	if (active) {
+		for (hwirq = GEF_PIC_NUM_IRQS - 1; hwirq > -1; hwirq--) {
+			if (active & (0x1 << hwirq))
+				break;
+		}
+		virq = irq_linear_revmap(gef_pic_irq_host,
+			(irq_hw_number_t)hwirq);
+	}
+
+	return virq;
+}
+
diff --git a/arch/powerpc/platforms/86xx/gef_pic.h b/arch/powerpc/platforms/86xx/gef_pic.h
new file mode 100644
index 00000000000..6149916da3f
--- /dev/null
+++ b/arch/powerpc/platforms/86xx/gef_pic.h
@@ -0,0 +1,11 @@
+#ifndef __GEF_PIC_H__
+#define __GEF_PIC_H__
+
+#include <linux/init.h>
+
+void gef_pic_cascade(unsigned int, struct irq_desc *);
+unsigned int gef_pic_get_irq(void);
+void gef_pic_init(struct device_node *);
+
+#endif /* __GEF_PIC_H__ */
+
diff --git a/arch/powerpc/platforms/86xx/gef_sbc610.c b/arch/powerpc/platforms/86xx/gef_sbc610.c
index ee215002b1c..3873c2018cc 100644
--- a/arch/powerpc/platforms/86xx/gef_sbc610.c
+++ b/arch/powerpc/platforms/86xx/gef_sbc610.c
@@ -39,6 +39,7 @@
 #include <sysdev/fsl_soc.h>
 
 #include "mpc86xx.h"
+#include "gef_pic.h"
 
 #undef DEBUG
 
@@ -48,6 +49,28 @@
 #define DBG (fmt...) do { } while (0)
 #endif
 
+void __iomem *sbc610_regs;
+
+static void __init gef_sbc610_init_irq(void)
+{
+	struct device_node *cascade_node = NULL;
+
+	mpc86xx_init_irq();
+
+	/*
+	 * There is a simple interrupt handler in the main FPGA, this needs
+	 * to be cascaded into the MPIC
+	 */
+	cascade_node = of_find_compatible_node(NULL, NULL, "gef,fpga-pic");
+	if (!cascade_node) {
+		printk(KERN_WARNING "SBC610: No FPGA PIC\n");
+		return;
+	}
+
+	gef_pic_init(cascade_node);
+	of_node_put(cascade_node);
+}
+
 static void __init gef_sbc610_setup_arch(void)
 {
 #ifdef CONFIG_PCI
@@ -145,7 +168,7 @@ define_machine(gef_sbc610) {
 	.name			= "GE Fanuc SBC610",
 	.probe			= gef_sbc610_probe,
 	.setup_arch		= gef_sbc610_setup_arch,
-	.init_IRQ		= mpc86xx_init_irq,
+	.init_IRQ		= gef_sbc610_init_irq,
 	.show_cpuinfo		= gef_sbc610_show_cpuinfo,
 	.get_irq		= mpic_get_irq,
 	.restart		= fsl_rstcr_restart,