MIPS: Alchemy: devboards: factor out PB1200 IRQ cascade code.

Move the PB1200 IRQ cascade code out to the BCSR support code:
upcoming DB1300 support can use it too.

Signed-off-by: Manuel Lauss <manuel.lauss@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/arch/mips/alchemy/devboards/bcsr.c b/arch/mips/alchemy/devboards/bcsr.c
index 85b7715901a..3bc4fd2155d 100644
--- a/arch/mips/alchemy/devboards/bcsr.c
+++ b/arch/mips/alchemy/devboards/bcsr.c
@@ -7,6 +7,7 @@
  * All registers are 16bits wide with 32bit spacing.
  */
 
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/spinlock.h>
 #include <asm/addrspace.h>
@@ -18,6 +19,9 @@ static struct bcsr_reg {
 	spinlock_t lock;
 } bcsr_regs[BCSR_CNT];
 
+static void __iomem *bcsr_virt;	/* KSEG1 addr of BCSR base */
+static int bcsr_csc_base;	/* linux-irq of first cascaded irq */
+
 void __init bcsr_init(unsigned long bcsr1_phys, unsigned long bcsr2_phys)
 {
 	int i;
@@ -25,6 +29,8 @@ void __init bcsr_init(unsigned long bcsr1_phys, unsigned long bcsr2_phys)
 	bcsr1_phys = KSEG1ADDR(CPHYSADDR(bcsr1_phys));
 	bcsr2_phys = KSEG1ADDR(CPHYSADDR(bcsr2_phys));
 
+	bcsr_virt = (void __iomem *)bcsr1_phys;
+
 	for (i = 0; i < BCSR_CNT; i++) {
 		if (i >= BCSR_HEXLEDS)
 			bcsr_regs[i].raddr = (void __iomem *)bcsr2_phys +
@@ -74,3 +80,69 @@ void bcsr_mod(enum bcsr_id reg, unsigned short clr, unsigned short set)
 	spin_unlock_irqrestore(&bcsr_regs[reg].lock, flags);
 }
 EXPORT_SYMBOL_GPL(bcsr_mod);
+
+/*
+ * DB1200/PB1200 CPLD IRQ muxer
+ */
+static void bcsr_csc_handler(unsigned int irq, struct irq_desc *d)
+{
+	unsigned short bisr = __raw_readw(bcsr_virt + BCSR_REG_INTSTAT);
+
+	for ( ; bisr; bisr &= bisr - 1)
+		generic_handle_irq(bcsr_csc_base + __ffs(bisr));
+}
+
+/* NOTE: both the enable and mask bits must be cleared, otherwise the
+ * CPLD generates tons of spurious interrupts (at least on my DB1200).
+ *	-- mlau
+ */
+static void bcsr_irq_mask(unsigned int irq_nr)
+{
+	unsigned short v = 1 << (irq_nr - bcsr_csc_base);
+	__raw_writew(v, bcsr_virt + BCSR_REG_INTCLR);
+	__raw_writew(v, bcsr_virt + BCSR_REG_MASKCLR);
+	wmb();
+}
+
+static void bcsr_irq_maskack(unsigned int irq_nr)
+{
+	unsigned short v = 1 << (irq_nr - bcsr_csc_base);
+	__raw_writew(v, bcsr_virt + BCSR_REG_INTCLR);
+	__raw_writew(v, bcsr_virt + BCSR_REG_MASKCLR);
+	__raw_writew(v, bcsr_virt + BCSR_REG_INTSTAT);	/* ack */
+	wmb();
+}
+
+static void bcsr_irq_unmask(unsigned int irq_nr)
+{
+	unsigned short v = 1 << (irq_nr - bcsr_csc_base);
+	__raw_writew(v, bcsr_virt + BCSR_REG_INTSET);
+	__raw_writew(v, bcsr_virt + BCSR_REG_MASKSET);
+	wmb();
+}
+
+static struct irq_chip bcsr_irq_type = {
+	.name		= "CPLD",
+	.mask		= bcsr_irq_mask,
+	.mask_ack	= bcsr_irq_maskack,
+	.unmask		= bcsr_irq_unmask,
+};
+
+void __init bcsr_init_irq(int csc_start, int csc_end, int hook_irq)
+{
+	unsigned int irq;
+
+	/* mask & disable & ack all */
+	__raw_writew(0xffff, bcsr_virt + BCSR_REG_INTCLR);
+	__raw_writew(0xffff, bcsr_virt + BCSR_REG_MASKCLR);
+	__raw_writew(0xffff, bcsr_virt + BCSR_REG_INTSTAT);
+	wmb();
+
+	bcsr_csc_base = csc_start;
+
+	for (irq = csc_start; irq <= csc_end; irq++)
+		set_irq_chip_and_handler_name(irq, &bcsr_irq_type,
+			handle_level_irq, "level");
+
+	set_irq_chained_handler(hook_irq, bcsr_csc_handler);
+}