sh: se722: Move FPGA IRQs to irqdomain and generic irq chip.

This implements a total rewrite of the rather buggy SE7722 FPGA IRQ code,
utilizing a linear irq domain as well as the generic irq chip type.

While the interaction between the two APIs is a bit clunky (ie, revmap
lookup for gc irq_base), they work well enough together that it's easy
enough to work with going forward.

While we're at it, deal with irq_mask_ack/unmask of the chained IRQ in
the demux handler to prevent smc91x screaming about spurious interrupts.

There's also some more improvement that can be made to the irqdomain code
to create backing irqdescs for the entire linear range in one bang
instead of iterating over the number of hwirqs and doing it
irq-at-a-time. This is easily dealt with at a later point, though.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

3 files changed, 91 insertions, 48 deletions

diff --git a/arch/sh/boards/Kconfig b/arch/sh/boards/Kconfig
index f2024a91..525b9e3 100644
--- a/arch/sh/boards/Kconfig
+++ b/arch/sh/boards/Kconfig
@@ -44,6 +44,8 @@ config SH_7721_SOLUTION_ENGINE
 config SH_7722_SOLUTION_ENGINE
 	bool "SolutionEngine7722"
 	select SOLUTION_ENGINE
+	select GENERIC_IRQ_CHIP
+	select IRQ_DOMAIN
 	depends on CPU_SUBTYPE_SH7722
 	help
 	  Select 7722 SolutionEngine if configuring for a Hitachi SH772
diff --git a/arch/sh/boards/mach-se/7722/irq.c b/arch/sh/boards/mach-se/7722/irq.c
index aac92f2..f5e2af1b 100644
--- a/arch/sh/boards/mach-se/7722/irq.c
+++ b/arch/sh/boards/mach-se/7722/irq.c
@@ -1,79 +1,96 @@
 /*
- * linux/arch/sh/boards/se/7722/irq.c
+ * Hitachi UL SolutionEngine 7722 FPGA IRQ Support.
  *
  * Copyright (C) 2007  Nobuhiro Iwamatsu
- *
- * Hitachi UL SolutionEngine 7722 Support.
+ * Copyright (C) 2012  Paul Mundt
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  */
+#define DRV_NAME "SE7722-FPGA"
+#define pr_fmt(fmt) DRV_NAME ": " fmt
+
+#define irq_reg_readl	ioread16
+#define irq_reg_writel	iowrite16
+
 #include <linux/init.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
-#include <asm/irq.h>
-#include <asm/io.h>
+#include <linux/irqdomain.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <asm/sizes.h>
 #include <mach-se/mach/se7722.h>
 
-unsigned int se7722_fpga_irq[SE7722_FPGA_IRQ_NR] = { 0, };
+#define IRQ01_BASE_ADDR	0x11800000
+#define IRQ01_MODE_REG	0
+#define IRQ01_STS_REG	4
+#define IRQ01_MASK_REG	8
 
-static void disable_se7722_irq(struct irq_data *data)
-{
-	unsigned int bit = (unsigned int)irq_data_get_irq_chip_data(data);
-	__raw_writew(__raw_readw(IRQ01_MASK) | 1 << bit, IRQ01_MASK);
-}
+static void __iomem *se7722_irq_regs;
+struct irq_domain *se7722_irq_domain;
 
-static void enable_se7722_irq(struct irq_data *data)
+static void se7722_irq_demux(unsigned int irq, struct irq_desc *desc)
 {
-	unsigned int bit = (unsigned int)irq_data_get_irq_chip_data(data);
-	__raw_writew(__raw_readw(IRQ01_MASK) & ~(1 << bit), IRQ01_MASK);
-}
+	struct irq_data *data = irq_get_irq_data(irq);
+	struct irq_chip *chip = irq_data_get_irq_chip(data);
+	unsigned long mask;
+	int bit;
 
-static struct irq_chip se7722_irq_chip __read_mostly = {
-	.name		= "SE7722-FPGA",
-	.irq_mask	= disable_se7722_irq,
-	.irq_unmask	= enable_se7722_irq,
-};
+	chip->irq_mask_ack(data);
 
-static void se7722_irq_demux(unsigned int irq, struct irq_desc *desc)
+	mask = ioread16(se7722_irq_regs + IRQ01_STS_REG);
+
+	for_each_set_bit(bit, &mask, SE7722_FPGA_IRQ_NR)
+		generic_handle_irq(irq_linear_revmap(se7722_irq_domain, bit));
+
+	chip->irq_unmask(data);
+}
+
+static void __init se7722_domain_init(void)
 {
-	unsigned short intv = __raw_readw(IRQ01_STS);
-	unsigned int ext_irq = 0;
+	int i;
 
-	intv &= (1 << SE7722_FPGA_IRQ_NR) - 1;
+	se7722_irq_domain = irq_domain_add_linear(NULL, SE7722_FPGA_IRQ_NR,
+						  &irq_domain_simple_ops, NULL);
+	if (unlikely(!se7722_irq_domain)) {
+		printk("Failed to get IRQ domain\n");
+		return;
+	}
 
-	for (; intv; intv >>= 1, ext_irq++) {
-		if (!(intv & 1))
-			continue;
+	for (i = 0; i < SE7722_FPGA_IRQ_NR; i++) {
+		int irq = irq_create_mapping(se7722_irq_domain, i);
 
-		generic_handle_irq(se7722_fpga_irq[ext_irq]);
+		if (unlikely(irq == 0)) {
+			printk("Failed to allocate IRQ %d\n", i);
+			return;
+		}
 	}
 }
 
-/*
- * Initialize IRQ setting
- */
-void __init init_se7722_IRQ(void)
+static void __init se7722_gc_init(void)
 {
-	int i, irq;
+	struct irq_chip_generic *gc;
+	struct irq_chip_type *ct;
+	unsigned int irq_base;
 
-	__raw_writew(0, IRQ01_MASK);       /* disable all irqs */
-	__raw_writew(0x2000, 0xb03fffec);  /* mrshpc irq enable */
+	irq_base = irq_linear_revmap(se7722_irq_domain, 0);
 
-	for (i = 0; i < SE7722_FPGA_IRQ_NR; i++) {
-		irq = create_irq();
-		if (irq < 0)
-			return;
-		se7722_fpga_irq[i] = irq;
+	gc = irq_alloc_generic_chip(DRV_NAME, 1, irq_base, se7722_irq_regs,
+				    handle_level_irq);
+	if (unlikely(!gc))
+		return;
 
-		irq_set_chip_and_handler_name(se7722_fpga_irq[i],
-					      &se7722_irq_chip,
-					      handle_level_irq,
-					      "level");
+	ct = gc->chip_types;
+	ct->chip.irq_mask = irq_gc_mask_set_bit;
+	ct->chip.irq_unmask = irq_gc_mask_clr_bit;
 
-		irq_set_chip_data(se7722_fpga_irq[i], (void *)i);
-	}
+	ct->regs.mask = IRQ01_MASK_REG;
+
+	irq_setup_generic_chip(gc, IRQ_MSK(SE7722_FPGA_IRQ_NR),
+			       IRQ_GC_INIT_MASK_CACHE,
+			       IRQ_NOREQUEST | IRQ_NOPROBE, 0);
 
 	irq_set_chained_handler(IRQ0_IRQ, se7722_irq_demux);
 	irq_set_irq_type(IRQ0_IRQ, IRQ_TYPE_LEVEL_LOW);
@@ -81,3 +98,25 @@ void __init init_se7722_IRQ(void)
 	irq_set_chained_handler(IRQ1_IRQ, se7722_irq_demux);
 	irq_set_irq_type(IRQ1_IRQ, IRQ_TYPE_LEVEL_LOW);
 }
+
+/*
+ * Initialize FPGA IRQs
+ */
+void __init init_se7722_IRQ(void)
+{
+	se7722_irq_regs = ioremap(IRQ01_BASE_ADDR, SZ_16);
+	if (unlikely(!se7722_irq_regs)) {
+		printk("Failed to remap IRQ01 regs\n");
+		return;
+	}
+
+	/*
+	 * All FPGA IRQs disabled by default
+	 */
+	iowrite16(0, se7722_irq_regs + IRQ01_MASK_REG);
+
+	__raw_writew(0x2000, 0xb03fffec);  /* mrshpc irq enable */
+
+	se7722_domain_init();
+	se7722_gc_init();
+}
diff --git a/arch/sh/boards/mach-se/7722/setup.c b/arch/sh/boards/mach-se/7722/setup.c
index e1963fe..2ec0111 100644
--- a/arch/sh/boards/mach-se/7722/setup.c
+++ b/arch/sh/boards/mach-se/7722/setup.c
@@ -2,6 +2,7 @@
  * linux/arch/sh/boards/se/7722/setup.c
  *
  * Copyright (C) 2007 Nobuhiro Iwamatsu
+ * Copyright (C) 2012 Paul Mundt
  *
  * Hitachi UL SolutionEngine 7722 Support.
  *
@@ -15,6 +16,7 @@
 #include <linux/ata_platform.h>
 #include <linux/input.h>
 #include <linux/input/sh_keysc.h>
+#include <linux/irqdomain.h>
 #include <linux/smc91x.h>
 #include <mach-se/mach/se7722.h>
 #include <mach-se/mach/mrshpc.h>
@@ -142,10 +144,10 @@ static int __init se7722_devices_setup(void)
 
 	/* Wire-up dynamic vectors */
 	cf_ide_resources[2].start = cf_ide_resources[2].end =
-		se7722_fpga_irq[SE7722_FPGA_IRQ_MRSHPC0];
+		irq_find_mapping(se7722_irq_domain, SE7722_FPGA_IRQ_MRSHPC0);
 
 	smc91x_eth_resources[1].start = smc91x_eth_resources[1].end =
-		se7722_fpga_irq[SE7722_FPGA_IRQ_SMC];
+		irq_find_mapping(se7722_irq_domain, SE7722_FPGA_IRQ_SMC);
 
 	return platform_add_devices(se7722_devices, ARRAY_SIZE(se7722_devices));
 }