ARM: OMAP4: PM: Add WakeupGen module as OMAP gic_arch_extn

OMAP WakeupGen is the interrupt controller extension used along
with ARM GIC to wake the CPU out from low power states on
external interrupts.

The WakeupGen unit is responsible for generating the wakeup event
from the incoming interrupts and enable bits. It is implemented
in the MPU always ON power domain. During normal operation,
WakeupGen delivers the external interrupts directly to the GIC.

WakeupGen specification has one restriction as per Veyron version 1.6.
It is SW responsibility to program interrupt enabling/disabling
coherently in the GIC and in the WakeupGen enable registers. That is, a
given interrupt for a given CPU is either enable at both GIC and WakeupGen,
or disable at both, but no mix. That's the reason the WakeupGen is
implemented as an extension of GIC.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

1 files changed, 226 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/omap-wakeupgen.c b/arch/arm/mach-omap2/omap-wakeupgen.c
new file mode 100644
index 000000000000..a8a8d0efe350
--- /dev/null
+++ b/arch/arm/mach-omap2/omap-wakeupgen.c
@@ -0,0 +1,226 @@
+/*
+ * OMAP WakeupGen Source file
+ *
+ * OMAP WakeupGen is the interrupt controller extension used along
+ * with ARM GIC to wake the CPU out from low power states on
+ * external interrupts. It is responsible for generating wakeup
+ * event from the incoming interrupts and enable bits. It is
+ * implemented in MPU always ON power domain. During normal operation,
+ * WakeupGen delivers external interrupts directly to the GIC.
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ *	Santosh Shilimkar <santosh.shilimkar@ti.com>
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/platform_device.h>
+#include <linux/cpu.h>
+
+#include <asm/hardware/gic.h>
+
+#include <mach/omap-wakeupgen.h>
+
+#define NR_REG_BANKS		4
+#define MAX_IRQS		128
+#define WKG_MASK_ALL		0x00000000
+#define WKG_UNMASK_ALL		0xffffffff
+#define CPU_ENA_OFFSET		0x400
+#define CPU0_ID			0x0
+#define CPU1_ID			0x1
+
+static void __iomem *wakeupgen_base;
+static DEFINE_PER_CPU(u32 [NR_REG_BANKS], irqmasks);
+static DEFINE_SPINLOCK(wakeupgen_lock);
+static unsigned int irq_target_cpu[NR_IRQS];
+
+/*
+ * Static helper functions.
+ */
+static inline u32 wakeupgen_readl(u8 idx, u32 cpu)
+{
+	return __raw_readl(wakeupgen_base + OMAP_WKG_ENB_A_0 +
+				(cpu * CPU_ENA_OFFSET) + (idx * 4));
+}
+
+static inline void wakeupgen_writel(u32 val, u8 idx, u32 cpu)
+{
+	__raw_writel(val, wakeupgen_base + OMAP_WKG_ENB_A_0 +
+				(cpu * CPU_ENA_OFFSET) + (idx * 4));
+}
+
+static void _wakeupgen_set_all(unsigned int cpu, unsigned int reg)
+{
+	u8 i;
+
+	for (i = 0; i < NR_REG_BANKS; i++)
+		wakeupgen_writel(reg, i, cpu);
+}
+
+static inline int _wakeupgen_get_irq_info(u32 irq, u32 *bit_posn, u8 *reg_index)
+{
+	unsigned int spi_irq;
+
+	/*
+	 * PPIs and SGIs are not supported.
+	 */
+	if (irq < OMAP44XX_IRQ_GIC_START)
+		return -EINVAL;
+
+	/*
+	 * Subtract the GIC offset.
+	 */
+	spi_irq = irq - OMAP44XX_IRQ_GIC_START;
+	if (spi_irq > MAX_IRQS) {
+		pr_err("omap wakeupGen: Invalid IRQ%d\n", irq);
+		return -EINVAL;
+	}
+
+	/*
+	 * Each WakeupGen register controls 32 interrupt.
+	 * i.e. 1 bit per SPI IRQ
+	 */
+	*reg_index = spi_irq >> 5;
+	*bit_posn = spi_irq %= 32;
+
+	return 0;
+}
+
+static void _wakeupgen_clear(unsigned int irq, unsigned int cpu)
+{
+	u32 val, bit_number;
+	u8 i;
+
+	if (_wakeupgen_get_irq_info(irq, &bit_number, &i))
+		return;
+
+	val = wakeupgen_readl(i, cpu);
+	val &= ~BIT(bit_number);
+	wakeupgen_writel(val, i, cpu);
+}
+
+static void _wakeupgen_set(unsigned int irq, unsigned int cpu)
+{
+	u32 val, bit_number;
+	u8 i;
+
+	if (_wakeupgen_get_irq_info(irq, &bit_number, &i))
+		return;
+
+	val = wakeupgen_readl(i, cpu);
+	val |= BIT(bit_number);
+	wakeupgen_writel(val, i, cpu);
+}
+
+static void _wakeupgen_save_masks(unsigned int cpu)
+{
+	u8 i;
+
+	for (i = 0; i < NR_REG_BANKS; i++)
+		per_cpu(irqmasks, cpu)[i] = wakeupgen_readl(i, cpu);
+}
+
+static void _wakeupgen_restore_masks(unsigned int cpu)
+{
+	u8 i;
+
+	for (i = 0; i < NR_REG_BANKS; i++)
+		wakeupgen_writel(per_cpu(irqmasks, cpu)[i], i, cpu);
+}
+
+/*
+ * Architecture specific Mask extension
+ */
+static void wakeupgen_mask(struct irq_data *d)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&wakeupgen_lock, flags);
+	_wakeupgen_clear(d->irq, irq_target_cpu[d->irq]);
+	spin_unlock_irqrestore(&wakeupgen_lock, flags);
+}
+
+/*
+ * Architecture specific Unmask extension
+ */
+static void wakeupgen_unmask(struct irq_data *d)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&wakeupgen_lock, flags);
+	_wakeupgen_set(d->irq, irq_target_cpu[d->irq]);
+	spin_unlock_irqrestore(&wakeupgen_lock, flags);
+}
+
+/*
+ * Mask or unmask all interrupts on given CPU.
+ *	0 = Mask all interrupts on the 'cpu'
+ *	1 = Unmask all interrupts on the 'cpu'
+ * Ensure that the initial mask is maintained. This is faster than
+ * iterating through GIC registers to arrive at the correct masks.
+ */
+static void wakeupgen_irqmask_all(unsigned int cpu, unsigned int set)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&wakeupgen_lock, flags);
+	if (set) {
+		_wakeupgen_save_masks(cpu);
+		_wakeupgen_set_all(cpu, WKG_MASK_ALL);
+	} else {
+		_wakeupgen_set_all(cpu, WKG_UNMASK_ALL);
+		_wakeupgen_restore_masks(cpu);
+	}
+	spin_unlock_irqrestore(&wakeupgen_lock, flags);
+}
+
+/*
+ * Initialise the wakeupgen module.
+ */
+int __init omap_wakeupgen_init(void)
+{
+	int i;
+	unsigned int boot_cpu = smp_processor_id();
+
+	/* Not supported on OMAP4 ES1.0 silicon */
+	if (omap_rev() == OMAP4430_REV_ES1_0) {
+		WARN(1, "WakeupGen: Not supported on OMAP4430 ES1.0\n");
+		return -EPERM;
+	}
+
+	/* Static mapping, never released */
+	wakeupgen_base = ioremap(OMAP44XX_WKUPGEN_BASE, SZ_4K);
+	if (WARN_ON(!wakeupgen_base))
+		return -ENOMEM;
+
+	/* Clear all IRQ bitmasks at wakeupGen level */
+	for (i = 0; i < NR_REG_BANKS; i++) {
+		wakeupgen_writel(0, i, CPU0_ID);
+		wakeupgen_writel(0, i, CPU1_ID);
+	}
+
+	/*
+	 * Override GIC architecture specific functions to add
+	 * OMAP WakeupGen interrupt controller along with GIC
+	 */
+	gic_arch_extn.irq_mask = wakeupgen_mask;
+	gic_arch_extn.irq_unmask = wakeupgen_unmask;
+	gic_arch_extn.flags = IRQCHIP_MASK_ON_SUSPEND | IRQCHIP_SKIP_SET_WAKE;
+
+	/*
+	 * FIXME: Add support to set_smp_affinity() once the core
+	 * GIC code has necessary hooks in place.
+	 */
+
+	/* Associate all the IRQs to boot CPU like GIC init does. */
+	for (i = 0; i < NR_IRQS; i++)
+		irq_target_cpu[i] = boot_cpu;
+
+	return 0;
+}