[RFC PATCH] arm: vt8500: Convert irq.c for multiplatform integration

[linux@prisktech.co.nz (Tony Prisk)]

This patch converts arch-vt8500/irq.c to MULTI_IRQ_HANDLER and
SPARSE_IRQ. IRQ domain is changed from legacy to linear.

Also, remove legacy code in include/mach/entry-macro.S and
include/mach/irq.h to prepare for multiplatform.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
---
 arch/arm/Kconfig                                |    2 +
 arch/arm/mach-vt8500/common.h                   |    3 +
 arch/arm/mach-vt8500/include/mach/entry-macro.S |   26 ------
 arch/arm/mach-vt8500/include/mach/irqs.h        |   22 -----
 arch/arm/mach-vt8500/irq.c                      |  111 +++++++++++++++--------
 arch/arm/mach-vt8500/vt8500.c                   |    1 +
 6 files changed, 79 insertions(+), 86 deletions(-)
 delete mode 100644 arch/arm/mach-vt8500/include/mach/entry-macro.S
 delete mode 100644 arch/arm/mach-vt8500/include/mach/irqs.h

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 6d2f7f5..32b62ac 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -949,6 +949,8 @@ config ARCH_VT8500
 	select COMMON_CLK
 	select HAVE_CLK
 	select CLKDEV_LOOKUP
+	select MULTI_IRQ_HANDLER
+	select SPARSE_IRQ
 	help
 	  Support for VIA/WonderMedia VT8500/WM85xx System-on-Chip.
 
diff --git a/arch/arm/mach-vt8500/common.h b/arch/arm/mach-vt8500/common.h
index 2b24196..6f2b843 100644
--- a/arch/arm/mach-vt8500/common.h
+++ b/arch/arm/mach-vt8500/common.h
@@ -25,4 +25,7 @@ int __init vt8500_irq_init(struct device_node *node,
 /* defined in drivers/clk/clk-vt8500.c */
 void __init vtwm_clk_init(void __iomem *pmc_base);
 
+/* defined in irq.c */
+asmlinkage void vt8500_handle_irq(struct pt_regs *regs);
+
 #endif
diff --git a/arch/arm/mach-vt8500/include/mach/entry-macro.S b/arch/arm/mach-vt8500/include/mach/entry-macro.S
deleted file mode 100644
index 367d1b5..0000000
--- a/arch/arm/mach-vt8500/include/mach/entry-macro.S
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- * arch/arm/mach-vt8500/include/mach/entry-macro.S
- *
- * Low-level IRQ helper macros for VIA VT8500
- *
- * This file is licensed under  the terms of the GNU General Public
- * License version 2. This program is licensed "as is" without any
- * warranty of any kind, whether express or implied.
- */
-
-	.macro  get_irqnr_preamble, base, tmp
-	@ physical 0xd8140000 is virtual 0xf8140000
-	mov	\base, #0xf8000000
-	orr	\base, \base, #0x00140000
-	.endm
-
-	.macro	get_irqnr_and_base, irqnr, irqstat, base, tmp
-	ldr	\irqnr, [\base]
-	cmp	\irqnr, #63 @ may be false positive, check interrupt status
-	bne	1001f
-	ldr	\irqstat, [\base, #0x84]
-	ands	\irqstat, #0x80000000
-	moveq	\irqnr, #0
-1001:
-	.endm
-
diff --git a/arch/arm/mach-vt8500/include/mach/irqs.h b/arch/arm/mach-vt8500/include/mach/irqs.h
deleted file mode 100644
index a129fd1..0000000
--- a/arch/arm/mach-vt8500/include/mach/irqs.h
+++ /dev/null
@@ -1,22 +0,0 @@
-/*
- *  arch/arm/mach-vt8500/include/mach/irqs.h
- *
- *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
- *
- * 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.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- */
-
-/* This value is just to make the core happy, never used otherwise */
-#define NR_IRQS 128
diff --git a/arch/arm/mach-vt8500/irq.c b/arch/arm/mach-vt8500/irq.c
index f8f9ab9..7e5fee9 100644
--- a/arch/arm/mach-vt8500/irq.c
+++ b/arch/arm/mach-vt8500/irq.c
@@ -36,7 +36,7 @@
 #include <linux/of_address.h>
 
 #include <asm/irq.h>
-
+#include <asm/exception.h>
 
 #define VT8500_ICPC_IRQ		0x20
 #define VT8500_ICPC_FIQ		0x24
@@ -66,30 +66,35 @@
 #define VT8500_EDGE		( VT8500_TRIGGER_RISING \
 				| VT8500_TRIGGER_FALLING)
 
-static int irq_cnt;
+/* vt8500 has 1 intc, wm8505 and wm8650 have 2 */
+#define VT8500_INTC_MAX		2
 
-struct vt8500_irq_priv {
-	void __iomem *base;
+struct vt8500_irq_data {
+	void __iomem 		*base;		/* IO Memory base address */
+	struct irq_domain	*domain;	/* Domain for this controller */
 };
 
+/* Global variable for accessing io-mem addresses */
+static struct vt8500_irq_data intc[VT8500_INTC_MAX];
+static u32 active_cnt = 0;
+
 static void vt8500_irq_mask(struct irq_data *d)
 {
-	struct vt8500_irq_priv *priv =
-			(struct vt8500_irq_priv *)(d->domain->host_data);
+	struct vt8500_irq_data *priv = 
+			(struct vt8500_irq_data *)(d->domain->host_data);
 	void __iomem *base = priv->base;
-	u8 edge;
+	void __iomem *stat_reg = base + VT8500_ICIS + (d->hwirq < 32 ? 0 : 4);
+	u8 edge, dctr;
+	u32 status;
 
 	edge = readb(base + VT8500_ICDC + d->hwirq) & VT8500_EDGE;
 	if (edge) {
-		void __iomem *stat_reg = base + VT8500_ICIS
-						+ (d->hwirq < 32 ? 0 : 4);
-		unsigned status = readl(stat_reg);
+		status = readl(stat_reg);
 
 		status |= (1 << (d->hwirq & 0x1f));
 		writel(status, stat_reg);
 	} else {
-		u8 dctr = readb(base + VT8500_ICDC + d->hwirq);
-
+		dctr = readb(base + VT8500_ICDC + d->hwirq);
 		dctr &= ~VT8500_INT_ENABLE;
 		writeb(dctr, base + VT8500_ICDC + d->hwirq);
 	}
@@ -97,8 +102,8 @@ static void vt8500_irq_mask(struct irq_data *d)
 
 static void vt8500_irq_unmask(struct irq_data *d)
 {
-	struct vt8500_irq_priv *priv =
-			(struct vt8500_irq_priv *)(d->domain->host_data);
+	struct vt8500_irq_data *priv = 
+			(struct vt8500_irq_data *)(d->domain->host_data);
 	void __iomem *base = priv->base;
 	u8 dctr;
 
@@ -109,8 +114,8 @@ static void vt8500_irq_unmask(struct irq_data *d)
 
 static int vt8500_irq_set_type(struct irq_data *d, unsigned int flow_type)
 {
-	struct vt8500_irq_priv *priv =
-			(struct vt8500_irq_priv *)(d->domain->host_data);
+	struct vt8500_irq_data *priv = 
+			(struct vt8500_irq_data *)(d->domain->host_data);
 	void __iomem *base = priv->base;
 	u8 dctr;
 
@@ -148,17 +153,15 @@ static struct irq_chip vt8500_irq_chip = {
 
 static void __init vt8500_init_irq_hw(void __iomem *base)
 {
-	unsigned int i;
+	u32 i;
 
 	/* Enable rotating priority for IRQ */
 	writel(ICPC_ROTATE, base + VT8500_ICPC_IRQ);
 	writel(0x00, base + VT8500_ICPC_FIQ);
 
-	for (i = 0; i < 64; i++) {
-		/* Disable all interrupts and route them to IRQ */
-		writeb(VT8500_INT_DISABLE | ICDC_IRQ,
-						base + VT8500_ICDC + i);
-	}
+	/* Disable all interrupts and route them to IRQ */
+	for (i = 0; i < 64; i++)
+		writeb(VT8500_INT_DISABLE | ICDC_IRQ, base + VT8500_ICDC + i);
 }
 
 static int vt8500_irq_map(struct irq_domain *h, unsigned int virq,
@@ -175,33 +178,67 @@ static struct irq_domain_ops vt8500_irq_domain_ops = {
 	.xlate = irq_domain_xlate_onecell,
 };
 
+asmlinkage void __exception_irq_entry vt8500_handle_irq(struct pt_regs *regs)
+{
+	u32 stat, i;
+	int irqnr, virq;
+	void __iomem *base;
+
+	/* Loop through each active controller */
+	for (i=0; i<active_cnt; i++) {
+		base = intc[i].base;
+		irqnr = readl_relaxed(base) & 0x3F;
+		/*
+		  Highest Priority register default = 63, so check that this
+		  is a real interrupt by checking the status register
+		*/
+		if (irqnr == 63) {
+			stat = readl_relaxed(base + VT8500_ICIS + 4);
+			if (!(stat & BIT(31)))
+				continue;
+		}
+
+		virq = irq_find_mapping(intc[i].domain, irqnr);
+		handle_IRQ(virq, regs);
+	}
+}
+
 int __init vt8500_irq_init(struct device_node *node, struct device_node *parent)
 {
-	struct irq_domain *vt8500_irq_domain;
-	struct vt8500_irq_priv *priv;
 	int irq, i;
 	struct device_node *np = node;
 
-	priv = kzalloc(sizeof(struct vt8500_irq_priv), GFP_KERNEL);
-	priv->base = of_iomap(np, 0);
+	if (active_cnt == VT8500_INTC_MAX) {
+		pr_err("%s: Interrupt controllers > VT8500_INTC_MAX\n",
+								__func__);
+		goto out;
+	}
+
+	intc[active_cnt].base = of_iomap(np, 0);
+	intc[active_cnt].domain = irq_domain_add_linear(node, 64,
+			&vt8500_irq_domain_ops,	&intc[active_cnt]);
 
-	vt8500_irq_domain = irq_domain_add_legacy(node, 64, irq_cnt, 0,
-				&vt8500_irq_domain_ops, priv);
-	if (!vt8500_irq_domain)
-		pr_err("%s: Unable to add wmt irq domain!\n", __func__);
+	if (!intc[active_cnt].base) {
+		pr_err("%s: Unable to map IO memory\n", __func__);
+		goto out;
+	}
+
+	if (!intc[active_cnt].domain) {
+		pr_err("%s: Unable to add irq domain!\n", __func__);
+		goto out;
+	}
 
-	irq_set_default_host(vt8500_irq_domain);
+	vt8500_init_irq_hw(intc[active_cnt].base);
 
-	vt8500_init_irq_hw(priv->base);
+	pr_info("vt8500-irq: Added interrupt controller\n");
 
-	pr_info("Added IRQ Controller @ %x [virq_base = %d]\n",
-						(u32)(priv->base), irq_cnt);
+	active_cnt++;
 
 	/* check if this is a slaved controller */
 	if (of_irq_count(np) != 0) {
 		/* check that we have the correct number of interrupts */
 		if (of_irq_count(np) != 8) {
-			pr_err("%s: Incorrect IRQ map for slave controller\n",
+			pr_err("%s: Incorrect IRQ map for slaved controller\n",
 					__func__);
 			return -EINVAL;
 		}
@@ -213,9 +250,7 @@ int __init vt8500_irq_init(struct device_node *node, struct device_node *parent)
 
 		pr_info("vt8500-irq: Enabled slave->parent interrupts\n");
 	}
-
-	irq_cnt += 64;
-
+out:
 	return 0;
 }
 
diff --git a/arch/arm/mach-vt8500/vt8500.c b/arch/arm/mach-vt8500/vt8500.c
index 8d3871f..14def0f 100644
--- a/arch/arm/mach-vt8500/vt8500.c
+++ b/arch/arm/mach-vt8500/vt8500.c
@@ -194,5 +194,6 @@ DT_MACHINE_START(WMT_DT, "VIA/Wondermedia SoC (Device Tree Support)")
 	.timer		= &vt8500_timer,
 	.init_machine	= vt8500_init,
 	.restart	= vt8500_restart,
+	.handle_irq	= vt8500_handle_irq,
 MACHINE_END
 
-- 
1.7.9.5