powerpc/mpc5121: Add support for CPLD on MPC5121ADS board

Add a interrupt host for the interrupt controller in the mpc5121ads cpld.
PCI interrupts are 0-7 the rest are 8-15 Touchscreen pendown irq is
hardwired to irq1 All other irqs are chained to irq0

Signed-off-by: John Rigby <jrigby@freescale.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 204 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/512x/mpc5121_ads_cpld.c b/arch/powerpc/platforms/512x/mpc5121_ads_cpld.c
new file mode 100644
index 000000000000..a6ce80566625
--- /dev/null
+++ b/arch/powerpc/platforms/512x/mpc5121_ads_cpld.c
@@ -0,0 +1,204 @@
+/*
+ * Copyright (C) 2008 Freescale Semiconductor, Inc. All rights reserved.
+ *
+ * Author: John Rigby, <jrigby@freescale.com>
+ *
+ * Description:
+ * MPC5121ADS CPLD irq handling
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <asm/prom.h>
+
+static struct device_node *cpld_pic_node;
+static struct irq_host *cpld_pic_host;
+
+/*
+ * Bits to ignore in the misc_status register
+ * 0x10 touch screen pendown is hard routed to irq1
+ * 0x02 pci status is read from pci status register
+ */
+#define MISC_IGNORE 0x12
+
+/*
+ * Nothing to ignore in pci status register
+ */
+#define PCI_IGNORE 0x00
+
+struct cpld_pic {
+	u8 pci_mask;
+	u8 pci_status;
+	u8 route;
+	u8 misc_mask;
+	u8 misc_status;
+	u8 misc_control;
+};
+
+static struct cpld_pic __iomem *cpld_regs;
+
+static void __iomem *
+irq_to_pic_mask(unsigned int irq)
+{
+	return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask;
+}
+
+static unsigned int
+irq_to_pic_bit(unsigned int irq)
+{
+	return 1 << (irq & 0x7);
+}
+
+static void
+cpld_mask_irq(unsigned int irq)
+{
+	unsigned int cpld_irq = (unsigned int)irq_map[irq].hwirq;
+	void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
+
+	out_8(pic_mask,
+	      in_8(pic_mask) | irq_to_pic_bit(cpld_irq));
+}
+
+static void
+cpld_unmask_irq(unsigned int irq)
+{
+	unsigned int cpld_irq = (unsigned int)irq_map[irq].hwirq;
+	void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
+
+	out_8(pic_mask,
+	      in_8(pic_mask) & ~irq_to_pic_bit(cpld_irq));
+}
+
+static struct irq_chip cpld_pic = {
+	.typename = " CPLD PIC ",
+	.mask = cpld_mask_irq,
+	.ack = cpld_mask_irq,
+	.unmask = cpld_unmask_irq,
+};
+
+static int
+cpld_pic_get_irq(int offset, u8 ignore, u8 __iomem *statusp,
+			    u8 __iomem *maskp)
+{
+	int cpld_irq;
+	u8 status = in_8(statusp);
+	u8 mask = in_8(maskp);
+
+	/* ignore don't cares and masked irqs */
+	status |= (ignore | mask);
+
+	if (status == 0xff)
+		return NO_IRQ_IGNORE;
+
+	cpld_irq = ffz(status) + offset;
+
+	return irq_linear_revmap(cpld_pic_host, cpld_irq);
+}
+
+static void
+cpld_pic_cascade(unsigned int irq, struct irq_desc *desc)
+{
+	irq = cpld_pic_get_irq(0, PCI_IGNORE, &cpld_regs->pci_status,
+		&cpld_regs->pci_mask);
+	if (irq != NO_IRQ && irq != NO_IRQ_IGNORE) {
+		generic_handle_irq(irq);
+		return;
+	}
+
+	irq = cpld_pic_get_irq(8, MISC_IGNORE, &cpld_regs->misc_status,
+		&cpld_regs->misc_mask);
+	if (irq != NO_IRQ && irq != NO_IRQ_IGNORE) {
+		generic_handle_irq(irq);
+		return;
+	}
+}
+
+static int
+cpld_pic_host_match(struct irq_host *h, struct device_node *node)
+{
+	return cpld_pic_node == node;
+}
+
+static int
+cpld_pic_host_map(struct irq_host *h, unsigned int virq,
+			     irq_hw_number_t hw)
+{
+	get_irq_desc(virq)->status |= IRQ_LEVEL;
+	set_irq_chip_and_handler(virq, &cpld_pic, handle_level_irq);
+	return 0;
+}
+
+static struct
+irq_host_ops cpld_pic_host_ops = {
+	.match = cpld_pic_host_match,
+	.map = cpld_pic_host_map,
+};
+
+void __init
+mpc5121_ads_cpld_map(void)
+{
+	struct device_node *np = NULL;
+
+	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
+	if (!np) {
+		printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
+		return;
+	}
+
+	cpld_regs = of_iomap(np, 0);
+	of_node_put(np);
+}
+
+void __init
+mpc5121_ads_cpld_pic_init(void)
+{
+	unsigned int cascade_irq;
+	struct device_node *np = NULL;
+
+	pr_debug("cpld_ic_init\n");
+
+	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
+	if (!np) {
+		printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
+		return;
+	}
+
+	if (!cpld_regs)
+		goto end;
+
+	cascade_irq = irq_of_parse_and_map(np, 0);
+	if (cascade_irq == NO_IRQ)
+		goto end;
+
+	/*
+	 * statically route touch screen pendown through 1
+	 * and ignore it here
+	 * route all others through our cascade irq
+	 */
+	out_8(&cpld_regs->route, 0xfd);
+	out_8(&cpld_regs->pci_mask, 0xff);
+	/* unmask pci ints in misc mask */
+	out_8(&cpld_regs->misc_mask, ~(MISC_IGNORE));
+
+	cpld_pic_node = of_node_get(np);
+
+	cpld_pic_host =
+	    irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, 16, &cpld_pic_host_ops, 16);
+	if (!cpld_pic_host) {
+		printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n");
+		goto end;
+	}
+
+	set_irq_chained_handler(cascade_irq, cpld_pic_cascade);
+end:
+	of_node_put(np);
+}