File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/parisc/gsc.c b/drivers/parisc/gsc.c
new file mode 100644
index 0000000..1bab5a2
--- /dev/null
+++ b/drivers/parisc/gsc.c
@@ -0,0 +1,248 @@
+/*
+ * Interrupt management for most GSC and related devices.
+ *
+ * (c) Copyright 1999 Alex deVries for The Puffin Group
+ * (c) Copyright 1999 Grant Grundler for Hewlett-Packard
+ * (c) Copyright 1999 Matthew Wilcox
+ * (c) Copyright 2000 Helge Deller
+ * (c) Copyright 2001 Matthew Wilcox for Hewlett-Packard
+ *
+ *	This program 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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/types.h>
+
+#include <asm/hardware.h>
+#include <asm/io.h>
+
+#include "gsc.h"
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define DEBPRINTK printk
+#else
+#define DEBPRINTK(x,...)
+#endif
+
+int gsc_alloc_irq(struct gsc_irq *i)
+{
+	int irq = txn_alloc_irq(GSC_EIM_WIDTH);
+	if (irq < 0) {
+		printk("cannot get irq\n");
+		return irq;
+	}
+
+	i->txn_addr = txn_alloc_addr(irq);
+	i->txn_data = txn_alloc_data(irq);
+	i->irq = irq;
+
+	return irq;
+}
+
+int gsc_claim_irq(struct gsc_irq *i, int irq)
+{
+	int c = irq;
+
+	irq += CPU_IRQ_BASE; /* virtualize the IRQ first */
+
+	irq = txn_claim_irq(irq);
+	if (irq < 0) {
+		printk("cannot claim irq %d\n", c);
+		return irq;
+	}
+
+	i->txn_addr = txn_alloc_addr(irq);
+	i->txn_data = txn_alloc_data(irq);
+	i->irq = irq;
+
+	return irq;
+}
+
+EXPORT_SYMBOL(gsc_alloc_irq);
+EXPORT_SYMBOL(gsc_claim_irq);
+
+/* Common interrupt demultiplexer used by Asp, Lasi & Wax.  */
+irqreturn_t gsc_asic_intr(int gsc_asic_irq, void *dev)
+{
+	unsigned long irr;
+	struct gsc_asic *gsc_asic = dev;
+
+	irr = gsc_readl(gsc_asic->hpa + OFFSET_IRR);
+	if (irr == 0)
+		return IRQ_NONE;
+
+	DEBPRINTK("%s intr, mask=0x%x\n", gsc_asic->name, irr);
+
+	do {
+		int local_irq = __ffs(irr);
+		unsigned int irq = gsc_asic->global_irq[local_irq];
+		generic_handle_irq(irq);
+		irr &= ~(1 << local_irq);
+	} while (irr);
+
+	return IRQ_HANDLED;
+}
+
+int gsc_find_local_irq(unsigned int irq, int *global_irqs, int limit)
+{
+	int local_irq;
+
+	for (local_irq = 0; local_irq < limit; local_irq++) {
+		if (global_irqs[local_irq] == irq)
+			return local_irq;
+	}
+
+	return NO_IRQ;
+}
+
+static void gsc_asic_mask_irq(struct irq_data *d)
+{
+	struct gsc_asic *irq_dev = irq_data_get_irq_chip_data(d);
+	int local_irq = gsc_find_local_irq(d->irq, irq_dev->global_irq, 32);
+	u32 imr;
+
+	DEBPRINTK(KERN_DEBUG "%s(%d) %s: IMR 0x%x\n", __func__, d->irq,
+			irq_dev->name, imr);
+
+	/* Disable the IRQ line by clearing the bit in the IMR */
+	imr = gsc_readl(irq_dev->hpa + OFFSET_IMR);
+	imr &= ~(1 << local_irq);
+	gsc_writel(imr, irq_dev->hpa + OFFSET_IMR);
+}
+
+static void gsc_asic_unmask_irq(struct irq_data *d)
+{
+	struct gsc_asic *irq_dev = irq_data_get_irq_chip_data(d);
+	int local_irq = gsc_find_local_irq(d->irq, irq_dev->global_irq, 32);
+	u32 imr;
+
+	DEBPRINTK(KERN_DEBUG "%s(%d) %s: IMR 0x%x\n", __func__, d->irq,
+			irq_dev->name, imr);
+
+	/* Enable the IRQ line by setting the bit in the IMR */
+	imr = gsc_readl(irq_dev->hpa + OFFSET_IMR);
+	imr |= 1 << local_irq;
+	gsc_writel(imr, irq_dev->hpa + OFFSET_IMR);
+	/*
+	 * FIXME: read IPR to make sure the IRQ isn't already pending.
+	 *   If so, we need to read IRR and manually call do_irq().
+	 */
+}
+
+static struct irq_chip gsc_asic_interrupt_type = {
+	.name		=	"GSC-ASIC",
+	.irq_unmask	=	gsc_asic_unmask_irq,
+	.irq_mask	=	gsc_asic_mask_irq,
+};
+
+int gsc_assign_irq(struct irq_chip *type, void *data)
+{
+	static int irq = GSC_IRQ_BASE;
+
+	if (irq > GSC_IRQ_MAX)
+		return NO_IRQ;
+
+	irq_set_chip_and_handler(irq, type, handle_simple_irq);
+	irq_set_chip_data(irq, data);
+
+	return irq++;
+}
+
+void gsc_asic_assign_irq(struct gsc_asic *asic, int local_irq, int *irqp)
+{
+	int irq = asic->global_irq[local_irq];
+	
+	if (irq <= 0) {
+		irq = gsc_assign_irq(&gsc_asic_interrupt_type, asic);
+		if (irq == NO_IRQ)
+			return;
+
+		asic->global_irq[local_irq] = irq;
+	}
+	*irqp = irq;
+}
+
+struct gsc_fixup_struct {
+	void (*choose_irq)(struct parisc_device *, void *);
+	void *ctrl;
+};
+
+static int gsc_fixup_irqs_callback(struct device *dev, void *data)
+{
+	struct parisc_device *padev = to_parisc_device(dev);
+	struct gsc_fixup_struct *gf = data;
+
+	/* work-around for 715/64 and others which have parent
+	   at path [5] and children at path [5/0/x] */
+	if (padev->id.hw_type == HPHW_FAULTY)
+		gsc_fixup_irqs(padev, gf->ctrl, gf->choose_irq);
+	gf->choose_irq(padev, gf->ctrl);
+
+	return 0;
+}
+
+void gsc_fixup_irqs(struct parisc_device *parent, void *ctrl,
+			void (*choose_irq)(struct parisc_device *, void *))
+{
+	struct gsc_fixup_struct data = {
+		.choose_irq	= choose_irq,
+		.ctrl		= ctrl,
+	};
+
+	device_for_each_child(&parent->dev, &data, gsc_fixup_irqs_callback);
+}
+
+int gsc_common_setup(struct parisc_device *parent, struct gsc_asic *gsc_asic)
+{
+	struct resource *res;
+	int i;
+
+	gsc_asic->gsc = parent;
+
+	/* Initialise local irq -> global irq mapping */
+	for (i = 0; i < 32; i++) {
+		gsc_asic->global_irq[i] = NO_IRQ;
+	}
+
+	/* allocate resource region */
+	res = request_mem_region(gsc_asic->hpa, 0x100000, gsc_asic->name);
+	if (res) {
+		res->flags = IORESOURCE_MEM; 	/* do not mark it busy ! */
+	}
+
+#if 0
+	printk(KERN_WARNING "%s IRQ %d EIM 0x%x", gsc_asic->name,
+			parent->irq, gsc_asic->eim);
+	if (gsc_readl(gsc_asic->hpa + OFFSET_IMR))
+		printk("  IMR is non-zero! (0x%x)",
+				gsc_readl(gsc_asic->hpa + OFFSET_IMR));
+	printk("\n");
+#endif
+
+	return 0;
+}
+
+extern struct parisc_driver lasi_driver;
+extern struct parisc_driver asp_driver;
+extern struct parisc_driver wax_driver;
+
+void __init gsc_init(void)
+{
+#ifdef CONFIG_GSC_LASI
+	register_parisc_driver(&lasi_driver);
+	register_parisc_driver(&asp_driver);
+#endif
+#ifdef CONFIG_GSC_WAX
+	register_parisc_driver(&wax_driver);
+#endif
+}