[ARM] 4739/1: at91sam9263: make gpio bank C and D irqs work

On the at91sam9263, IRQs for GPIO banks C and D don't currently work.
This is because banks C, D, and E share one clock and toplevel IRQ, but
the AT91 code setting up and handling GPIO IRQs expects no sharing.
This patch:

 - Fixes GPIO IRQ setup and handling to cope with GPIO banks that are
   shared like on sam9263 chips, by setting up a list of those banks
   and making the IRQ dispatching logic scan that list.

 - Precomputes the address of each bank's registers, saving it with
   other per-bank data so that it no longer needs to be constantly
   recomputed during IRQs and other GPIO operations.  That shrinks
   hot-path code, while helping the GPIO bank irq updates.

 - Fixes a minor bug where IRQ_TYPE_NONE was wrongly rejected (it just
   means "use the default", which is "both edges" here).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-at91/generic.h

@@ -47,6 +47,9 @@ extern void at91_irq_resume(void);
 #define AT91RM9200_BGA		4	/* AT91RM9200 BGA package has 4 banks */
 
 struct at91_gpio_bank {
+	unsigned chipbase;		/* bank's first GPIO number */
+	void __iomem *regbase;		/* base of register bank */
+	struct at91_gpio_bank *next;	/* bank sharing same IRQ/clock/... */
 	unsigned short id;		/* peripheral ID */
 	unsigned long offset;		/* offset from system peripheral base */
 	struct clk *clock;		/* associated clock */

arch/arm/mach-at91/gpio.c

@@ -33,12 +33,10 @@ static int gpio_banks;
 
 static inline void __iomem *pin_to_controller(unsigned pin)
 {
-	void __iomem *sys_base = (void __iomem *) AT91_VA_BASE_SYS;
-
 	pin -= PIN_BASE;
 	pin /= 32;
 	if (likely(pin < gpio_banks))
-		return sys_base + gpio[pin].offset;
+		return gpio[pin].regbase;
 
 	return NULL;
 }
@@ -294,11 +292,11 @@ void at91_gpio_suspend(void)
 	int i;
 
 	for (i = 0; i < gpio_banks; i++) {
-		u32 pio = gpio[i].offset;
+		void __iomem	*pio = gpio[i].regbase;
 
-		backups[i] = at91_sys_read(pio + PIO_IMR);
-		at91_sys_write(pio + PIO_IDR, backups[i]);
-		at91_sys_write(pio + PIO_IER, wakeups[i]);
+		backups[i] = __raw_readl(pio + PIO_IMR);
+		__raw_writel(backups[i], pio + PIO_IDR);
+		__raw_writel(wakeups[i], pio + PIO_IER);
 
 		if (!wakeups[i])
 			clk_disable(gpio[i].clock);
@@ -315,13 +313,13 @@ void at91_gpio_resume(void)
 	int i;
 
 	for (i = 0; i < gpio_banks; i++) {
-		u32 pio = gpio[i].offset;
+		void __iomem	*pio = gpio[i].regbase;
 
 		if (!wakeups[i])
 			clk_enable(gpio[i].clock);
 
-		at91_sys_write(pio + PIO_IDR, wakeups[i]);
-		at91_sys_write(pio + PIO_IER, backups[i]);
+		__raw_writel(wakeups[i], pio + PIO_IDR);
+		__raw_writel(backups[i], pio + PIO_IER);
 	}
 }
 
@@ -361,7 +359,13 @@ static void gpio_irq_unmask(unsigned pin)
 
 static int gpio_irq_type(unsigned pin, unsigned type)
 {
-	return (type == IRQT_BOTHEDGE) ? 0 : -EINVAL;
+	switch (type) {
+	case IRQ_TYPE_NONE:
+	case IRQ_TYPE_EDGE_BOTH:
+		return 0;
+	default:
+		return -EINVAL;
+	}
 }
 
 static struct irq_chip gpio_irqchip = {
@@ -376,20 +380,30 @@ static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
 {
 	unsigned	pin;
 	struct irq_desc	*gpio;
+	struct at91_gpio_bank *bank;
 	void __iomem	*pio;
 	u32		isr;
 
-	pio = get_irq_chip_data(irq);
+	bank = get_irq_chip_data(irq);
+	pio = bank->regbase;
 
 	/* temporarily mask (level sensitive) parent IRQ */
 	desc->chip->ack(irq);
 	for (;;) {
-		/* reading ISR acks the pending (edge triggered) GPIO interrupt */
+		/* Reading ISR acks pending (edge triggered) GPIO interrupts.
+		 * When there none are pending, we're finished unless we need
+		 * to process multiple banks (like ID_PIOCDE on sam9263).
+		 */
 		isr = __raw_readl(pio + PIO_ISR) & __raw_readl(pio + PIO_IMR);
-		if (!isr)
-			break;
+		if (!isr) {
+			if (!bank->next)
+				break;
+			bank = bank->next;
+			pio = bank->regbase;
+			continue;
+		}
 
-		pin = (unsigned) get_irq_data(irq);
+		pin = bank->chipbase;
 		gpio = &irq_desc[pin];
 
 		while (isr) {
@@ -481,24 +495,21 @@ postcore_initcall(at91_gpio_debugfs_init);
  */
 void __init at91_gpio_irq_setup(void)
 {
-	unsigned	pioc, pin;
+	unsigned		pioc, pin;
+	struct at91_gpio_bank	*this, *prev;
 
-	for (pioc = 0, pin = PIN_BASE;
-			pioc < gpio_banks;
-			pioc++) {
-		void __iomem	*controller;
-		unsigned	id = gpio[pioc].id;
+	for (pioc = 0, pin = PIN_BASE, this = gpio, prev = NULL;
+			pioc++ < gpio_banks;
+			prev = this, this++) {
+		unsigned	id = this->id;
 		unsigned	i;
 
-		clk_enable(gpio[pioc].clock);	/* enable PIO controller's clock */
-
-		controller = (void __iomem *) AT91_VA_BASE_SYS + gpio[pioc].offset;
-		__raw_writel(~0, controller + PIO_IDR);
+		/* enable PIO controller's clock */
+		clk_enable(this->clock);
 
-		set_irq_data(id, (void *) pin);
-		set_irq_chip_data(id, controller);
+		__raw_writel(~0, this->regbase + PIO_IDR);
 
-		for (i = 0; i < 32; i++, pin++) {
+		for (i = 0, pin = this->chipbase; i < 32; i++, pin++) {
 			/*
 			 * Can use the "simple" and not "edge" handler since it's
 			 * shorter, and the AIC handles interrupts sanely.
@@ -508,6 +519,14 @@ void __init at91_gpio_irq_setup(void)
 			set_irq_flags(pin, IRQF_VALID);
 		}
 
+		/* The toplevel handler handles one bank of GPIOs, except
+		 * AT91SAM9263_ID_PIOCDE handles three... PIOC is first in
+		 * the list, so we only set up that handler.
+		 */
+		if (prev && prev->next == this)
+			continue;
+
+		set_irq_chip_data(id, this);
 		set_irq_chained_handler(id, gpio_irq_handler);
 	}
 	pr_info("AT91: %d gpio irqs in %d banks\n", pin - PIN_BASE, gpio_banks);
@@ -518,8 +537,20 @@ void __init at91_gpio_irq_setup(void)
  */
 void __init at91_gpio_init(struct at91_gpio_bank *data, int nr_banks)
 {
+	unsigned		i;
+	struct at91_gpio_bank	*last;
+
 	BUG_ON(nr_banks > MAX_GPIO_BANKS);
 
 	gpio = data;
 	gpio_banks = nr_banks;
+
+	for (i = 0, last = NULL; i < nr_banks; i++, last = data, data++) {
+		data->chipbase = PIN_BASE + i * 32;
+		data->regbase = data->offset + (void __iomem *)AT91_VA_BASE_SYS;
+
+		/* AT91SAM9263_ID_PIOCDE groups PIOC, PIOD, PIOE */
+		if (last && last->id == data->id)
+			last->next = data;
+	}
 }