MN10300: ASB2364: Handle the IRQ multiplexer in the FPGA

Handle the IRQ multiplexer in the FPGA by implementing a cascade interrupt
driver for it.

Signed-off-by: David Howells <dhowells@redhat.com>

7 files changed, 166 insertions, 19 deletions

diff --git a/arch/mn10300/include/asm/irq.h b/arch/mn10300/include/asm/irq.h
index b7b8e175b167..1a73fb3f60c6 100644
--- a/arch/mn10300/include/asm/irq.h
+++ b/arch/mn10300/include/asm/irq.h
@@ -21,11 +21,15 @@
 /* this number is used when no interrupt has been assigned */
 #define NO_IRQ          INT_MAX
 
-/* hardware irq numbers */
-#ifdef CONFIG_SMP
-#define NR_IRQS         GxICR_NUM_EXT_IRQS
+/*
+ * hardware irq numbers
+ * - the ASB2364 has an FPGA with an IRQ multiplexer on it
+ */
+#ifdef CONFIG_MN10300_UNIT_ASB2364
+#include <unit/irq.h>
 #else
-#define NR_IRQS         GxICR_NUM_IRQS
+#define NR_CPU_IRQS     GxICR_NUM_IRQS
+#define NR_IRQS         NR_CPU_IRQS
 #endif
 
 /* external hardware irq numbers */
diff --git a/arch/mn10300/kernel/irq.c b/arch/mn10300/kernel/irq.c
index 2f66a45dcd18..c2e44597c22b 100644
--- a/arch/mn10300/kernel/irq.c
+++ b/arch/mn10300/kernel/irq.c
@@ -381,9 +381,16 @@ int show_interrupts(struct seq_file *p, void *v)
                         seq_printf(p, "%3d: ", i);
                         for_each_present_cpu(cpu)
                                 seq_printf(p, "%10u ", kstat_irqs_cpu(i, cpu));
-                        seq_printf(p, " %14s.%u", irq_desc[i].chip->name,
-                                   (GxICR(i) & GxICR_LEVEL) >>
-                                   GxICR_LEVEL_SHIFT);
+
+                        if (i < NR_CPU_IRQS)
+                                seq_printf(p, " %14s.%u",
+                                           irq_desc[i].chip->name,
+                                           (GxICR(i) & GxICR_LEVEL) >>
+                                           GxICR_LEVEL_SHIFT);
+                        else
+                                seq_printf(p, " %14s",
+                                           irq_desc[i].chip->name);
+
                         seq_printf(p, "  %s", action->name);
 
                         for (action = action->next;
diff --git a/arch/mn10300/unit-asb2364/Makefile b/arch/mn10300/unit-asb2364/Makefile
index 6dd27d65877a..e9d9b90ef6da 100644
--- a/arch/mn10300/unit-asb2364/Makefile
+++ b/arch/mn10300/unit-asb2364/Makefile
@@ -7,4 +7,4 @@
 #
 # Note 2! The CFLAGS definitions are now in the main makefile...
 
-obj-y   := unit-init.o leds.o
+obj-y   := unit-init.o leds.o irq-fpga.o
diff --git a/arch/mn10300/unit-asb2364/include/unit/fpga-regs.h b/arch/mn10300/unit-asb2364/include/unit/fpga-regs.h
index a039a50c91db..7cf12054db65 100644
--- a/arch/mn10300/unit-asb2364/include/unit/fpga-regs.h
+++ b/arch/mn10300/unit-asb2364/include/unit/fpga-regs.h
@@ -14,17 +14,19 @@
 #define ASB2364_FPGA_REG_RESET_USB      __SYSREG(0xa900130c, u16)
 #define ASB2364_FPGA_REG_RESET_AV       __SYSREG(0xa9001310, u16)
 
-#define ASB2364_FPGA_REG_IRQ_LAN        __SYSREG(0xa9001510, u16)
-#define ASB2364_FPGA_REG_IRQ_UART       __SYSREG(0xa9001514, u16)
-#define ASB2364_FPGA_REG_IRQ_I2C        __SYSREG(0xa9001518, u16)
-#define ASB2364_FPGA_REG_IRQ_USB        __SYSREG(0xa900151c, u16)
-#define ASB2364_FPGA_REG_IRQ_FPGA       __SYSREG(0xa9001524, u16)
-
-#define ASB2364_FPGA_REG_MASK_LAN       __SYSREG(0xa9001590, u16)
-#define ASB2364_FPGA_REG_MASK_UART      __SYSREG(0xa9001594, u16)
-#define ASB2364_FPGA_REG_MASK_I2C       __SYSREG(0xa9001598, u16)
-#define ASB2364_FPGA_REG_MASK_USB       __SYSREG(0xa900159c, u16)
-#define ASB2364_FPGA_REG_MASK_FPGA      __SYSREG(0xa90015a4, u16)
+#define ASB2364_FPGA_REG_IRQ(X)         __SYSREG(0xa9001590+((X)*4), u16)
+#define ASB2364_FPGA_REG_IRQ_LAN        ASB2364_FPGA_REG_IRQ(0)
+#define ASB2364_FPGA_REG_IRQ_UART       ASB2364_FPGA_REG_IRQ(1)
+#define ASB2364_FPGA_REG_IRQ_I2C        ASB2364_FPGA_REG_IRQ(2)
+#define ASB2364_FPGA_REG_IRQ_USB        ASB2364_FPGA_REG_IRQ(3)
+#define ASB2364_FPGA_REG_IRQ_FPGA       ASB2364_FPGA_REG_IRQ(5)
+
+#define ASB2364_FPGA_REG_MASK(X)        __SYSREG(0xa9001590+((X)*4), u16)
+#define ASB2364_FPGA_REG_MASK_LAN       ASB2364_FPGA_REG_MASK(0)
+#define ASB2364_FPGA_REG_MASK_UART      ASB2364_FPGA_REG_MASK(1)
+#define ASB2364_FPGA_REG_MASK_I2C       ASB2364_FPGA_REG_MASK(2)
+#define ASB2364_FPGA_REG_MASK_USB       ASB2364_FPGA_REG_MASK(3)
+#define ASB2364_FPGA_REG_MASK_FPGA      ASB2364_FPGA_REG_MASK(5)
 
 #define ASB2364_FPGA_REG_CPLD5_SET1     __SYSREG(0xa9002500, u16)
 #define ASB2364_FPGA_REG_CPLD5_SET2     __SYSREG(0xa9002504, u16)
diff --git a/arch/mn10300/unit-asb2364/include/unit/irq.h b/arch/mn10300/unit-asb2364/include/unit/irq.h
new file mode 100644
index 000000000000..786148e46565
--- /dev/null
+++ b/arch/mn10300/unit-asb2364/include/unit/irq.h
@@ -0,0 +1,35 @@
+/* ASB2364 FPGA irq numbers
+ *
+ * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#ifndef _UNIT_IRQ_H
+#define _UNIT_IRQ_H
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_SMP
+#define NR_CPU_IRQS     GxICR_NUM_EXT_IRQS
+#else
+#define NR_CPU_IRQS     GxICR_NUM_IRQS
+#endif
+
+enum {
+        FPGA_LAN_IRQ    = NR_CPU_IRQS,
+        FPGA_UART_IRQ,
+        FPGA_I2C_IRQ,
+        FPGA_USB_IRQ,
+        FPGA_RESERVED_IRQ,
+        FPGA_FPGA_IRQ,
+        NR_IRQS
+};
+
+extern void __init irq_fpga_init(void);
+
+#endif /* !__ASSEMBLY__ */
+#endif /* _UNIT_IRQ_H */
diff --git a/arch/mn10300/unit-asb2364/irq-fpga.c b/arch/mn10300/unit-asb2364/irq-fpga.c
new file mode 100644
index 000000000000..fcf29754e4d1
--- /dev/null
+++ b/arch/mn10300/unit-asb2364/irq-fpga.c
@@ -0,0 +1,96 @@
+/* ASB2364 FPGA interrupt multiplexing
+ *
+ * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <unit/fpga-regs.h>
+
+/*
+ * FPGA PIC operations
+ */
+static void asb2364_fpga_mask(unsigned int irq)
+{
+        ASB2364_FPGA_REG_MASK(irq - NR_CPU_IRQS) = 0x0001;
+        SyncExBus();
+}
+
+static void asb2364_fpga_ack(unsigned int irq)
+{
+        ASB2364_FPGA_REG_IRQ(irq - NR_CPU_IRQS) = 0x0001;
+        SyncExBus();
+}
+
+static void asb2364_fpga_mask_ack(unsigned int irq)
+{
+        ASB2364_FPGA_REG_MASK(irq - NR_CPU_IRQS) = 0x0001;
+        SyncExBus();
+        ASB2364_FPGA_REG_IRQ(irq - NR_CPU_IRQS) = 0x0001;
+        SyncExBus();
+}
+
+static void asb2364_fpga_unmask(unsigned int irq)
+{
+        ASB2364_FPGA_REG_MASK(irq - NR_CPU_IRQS) = 0x0000;
+        SyncExBus();
+}
+
+static struct irq_chip asb2364_fpga_pic = {
+        .name           = "fpga",
+        .ack            = asb2364_fpga_ack,
+        .mask           = asb2364_fpga_mask,
+        .mask_ack       = asb2364_fpga_mask_ack,
+        .unmask         = asb2364_fpga_unmask,
+};
+
+/*
+ * FPGA PIC interrupt handler
+ */
+static irqreturn_t fpga_interrupt(int irq, void *_mask)
+{
+        if ((ASB2364_FPGA_REG_IRQ_LAN  & 0x0001) != 0x0001)
+                generic_handle_irq(FPGA_LAN_IRQ);
+        if ((ASB2364_FPGA_REG_IRQ_UART & 0x0001) != 0x0001)
+                generic_handle_irq(FPGA_UART_IRQ);
+        if ((ASB2364_FPGA_REG_IRQ_I2C  & 0x0001) != 0x0001)
+                generic_handle_irq(FPGA_I2C_IRQ);
+        if ((ASB2364_FPGA_REG_IRQ_USB  & 0x0001) != 0x0001)
+                generic_handle_irq(FPGA_USB_IRQ);
+        if ((ASB2364_FPGA_REG_IRQ_FPGA & 0x0001) != 0x0001)
+                generic_handle_irq(FPGA_FPGA_IRQ);
+
+        return IRQ_HANDLED;
+}
+
+/*
+ * Define an interrupt action for each FPGA PIC output
+ */
+static struct irqaction fpga_irq[]  = {
+        [0] = {
+                .handler        = fpga_interrupt,
+                .flags          = IRQF_DISABLED | IRQF_SHARED,
+                .name           = "fpga",
+        },
+};
+
+/*
+ * Initialise the FPGA's PIC
+ */
+void __init irq_fpga_init(void)
+{
+        int irq;
+
+        for (irq = NR_CPU_IRQS; irq < NR_IRQS; irq++)
+                set_irq_chip_and_handler(irq, &asb2364_fpga_pic, handle_level_irq);
+
+        /* the FPGA drives the XIRQ1 input on the CPU PIC */
+        setup_irq(XIRQ1, &fpga_irq[0]);
+}
diff --git a/arch/mn10300/unit-asb2364/unit-init.c b/arch/mn10300/unit-asb2364/unit-init.c
index a3fc09b43f84..11440803db10 100644
--- a/arch/mn10300/unit-asb2364/unit-init.c
+++ b/arch/mn10300/unit-asb2364/unit-init.c
@@ -20,6 +20,7 @@
 #include <asm/processor.h>
 #include <asm/irq.h>
 #include <asm/intctl-regs.h>
+#include <unit/fpga-regs.h>
 
 /*
  * initialise some of the unit hardware before gdbstub is set up
@@ -82,4 +83,6 @@ void __init unit_init_IRQ(void)
 
 #define IRQCTL  __SYSREG(0xd5000090, u32)
         IRQCTL |= 0x02;
+
+        irq_fpga_init();
 }