MIPS: bcm3384: Initial commit of bcm3384 platform support

This supports SMP Linux running on the BCM3384 Zephyr (BMIPS5000)
application processor, with fully functional UART and USB 1.1/2.0.
Device Tree is used to configure the following items:

 - All peripherals
 - Early console base address
 - SMP or UP mode
 - MIPS counter frequency
 - Memory size / regions
 - DMA offset
 - Kernel command line

The DT-enabled bootloader and build instructions are posted at
https://github.com/Broadcom/aeolus

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: jfraser@broadcom.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8170/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 193 insertions, 0 deletions

diff --git a/arch/mips/bcm3384/irq.c b/arch/mips/bcm3384/irq.c
new file mode 100644
index 000000000000..0fb5134fb832
--- /dev/null
+++ b/arch/mips/bcm3384/irq.c
@@ -0,0 +1,193 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * Partially based on arch/mips/ralink/irq.c
+ *
+ * Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ * Copyright (C) 2014 Kevin Cernekee <cernekee@gmail.com>
+ */
+
+#include <linux/io.h>
+#include <linux/bitops.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <asm/bmips.h>
+#include <asm/irq_cpu.h>
+#include <asm/mipsregs.h>
+
+/* INTC register offsets */
+#define INTC_REG_ENABLE		0x00
+#define INTC_REG_STATUS		0x04
+
+#define MAX_WORDS		2
+#define IRQS_PER_WORD		32
+
+struct bcm3384_intc {
+	int			n_words;
+	void __iomem		*reg[MAX_WORDS];
+	u32			enable[MAX_WORDS];
+	spinlock_t		lock;
+};
+
+static void bcm3384_intc_irq_unmask(struct irq_data *d)
+{
+	struct bcm3384_intc *priv = d->domain->host_data;
+	unsigned long flags;
+	int idx = d->hwirq / IRQS_PER_WORD;
+	int bit = d->hwirq % IRQS_PER_WORD;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->enable[idx] |= BIT(bit);
+	__raw_writel(priv->enable[idx], priv->reg[idx] + INTC_REG_ENABLE);
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static void bcm3384_intc_irq_mask(struct irq_data *d)
+{
+	struct bcm3384_intc *priv = d->domain->host_data;
+	unsigned long flags;
+	int idx = d->hwirq / IRQS_PER_WORD;
+	int bit = d->hwirq % IRQS_PER_WORD;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->enable[idx] &= ~BIT(bit);
+	__raw_writel(priv->enable[idx], priv->reg[idx] + INTC_REG_ENABLE);
+	spin_unlock_irqrestore(&priv->lock, flags);
+}
+
+static struct irq_chip bcm3384_intc_irq_chip = {
+	.name		= "INTC",
+	.irq_unmask	= bcm3384_intc_irq_unmask,
+	.irq_mask	= bcm3384_intc_irq_mask,
+	.irq_mask_ack	= bcm3384_intc_irq_mask,
+};
+
+unsigned int get_c0_compare_int(void)
+{
+	return CP0_LEGACY_COMPARE_IRQ;
+}
+
+static void bcm3384_intc_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+	struct irq_domain *domain = irq_get_handler_data(irq);
+	struct bcm3384_intc *priv = domain->host_data;
+	unsigned long flags;
+	unsigned int idx;
+
+	for (idx = 0; idx < priv->n_words; idx++) {
+		unsigned long pending;
+		int hwirq;
+
+		spin_lock_irqsave(&priv->lock, flags);
+		pending = __raw_readl(priv->reg[idx] + INTC_REG_STATUS) &
+			  priv->enable[idx];
+		spin_unlock_irqrestore(&priv->lock, flags);
+
+		for_each_set_bit(hwirq, &pending, IRQS_PER_WORD) {
+			generic_handle_irq(irq_find_mapping(domain,
+					   hwirq + idx * IRQS_PER_WORD));
+		}
+	}
+}
+
+asmlinkage void plat_irq_dispatch(void)
+{
+	unsigned long pending =
+		(read_c0_status() & read_c0_cause() & ST0_IM) >> STATUSB_IP0;
+	int bit;
+
+	for_each_set_bit(bit, &pending, 8)
+		do_IRQ(MIPS_CPU_IRQ_BASE + bit);
+}
+
+static int intc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
+{
+	irq_set_chip_and_handler(irq, &bcm3384_intc_irq_chip, handle_level_irq);
+	return 0;
+}
+
+static const struct irq_domain_ops irq_domain_ops = {
+	.xlate = irq_domain_xlate_onecell,
+	.map = intc_map,
+};
+
+static int __init ioremap_one_pair(struct bcm3384_intc *priv,
+				   struct device_node *node,
+				   int idx)
+{
+	struct resource res;
+
+	if (of_address_to_resource(node, idx, &res))
+		return 0;
+
+	if (request_mem_region(res.start, resource_size(&res),
+			       res.name) < 0)
+		pr_err("Failed to request INTC register region\n");
+
+	priv->reg[idx] = ioremap_nocache(res.start, resource_size(&res));
+	if (!priv->reg[idx])
+		panic("Failed to ioremap INTC register range");
+
+	/* start up with everything masked before we hook the parent IRQ */
+	__raw_writel(0, priv->reg[idx] + INTC_REG_ENABLE);
+	priv->enable[idx] = 0;
+
+	return IRQS_PER_WORD;
+}
+
+static int __init intc_of_init(struct device_node *node,
+			       struct device_node *parent)
+{
+	struct irq_domain *domain;
+	unsigned int parent_irq, n_irqs = 0;
+	struct bcm3384_intc *priv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		panic("Failed to allocate bcm3384_intc struct");
+
+	spin_lock_init(&priv->lock);
+
+	parent_irq = irq_of_parse_and_map(node, 0);
+	if (!parent_irq)
+		panic("Failed to get INTC IRQ");
+
+	n_irqs += ioremap_one_pair(priv, node, 0);
+	n_irqs += ioremap_one_pair(priv, node, 1);
+
+	if (!n_irqs)
+		panic("Failed to map INTC registers");
+
+	priv->n_words = n_irqs / IRQS_PER_WORD;
+	domain = irq_domain_add_linear(node, n_irqs, &irq_domain_ops, priv);
+	if (!domain)
+		panic("Failed to add irqdomain");
+
+	irq_set_chained_handler(parent_irq, bcm3384_intc_irq_handler);
+	irq_set_handler_data(parent_irq, domain);
+
+	return 0;
+}
+
+static struct of_device_id of_irq_ids[] __initdata = {
+	{ .compatible = "mti,cpu-interrupt-controller",
+	  .data = mips_cpu_intc_init },
+	{ .compatible = "brcm,bcm3384-intc",
+	  .data = intc_of_init },
+	{},
+};
+
+void __init arch_init_irq(void)
+{
+	bmips_tp1_irqs = 0;
+	of_irq_init(of_irq_ids);
+}