ARM: 6091/1: ST SPEAr: Adding support for shared irq layer
Multiple peripherals in SPEAr share common hardware interrupt lines.
This patch adds support for a shared irq layer, which registers hardware
irqs by itself and exposes virtual irq numbers to peripherals.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/plat-spear/shirq.c b/arch/arm/plat-spear/shirq.c
new file mode 100644
index 0000000..2172d69
--- /dev/null
+++ b/arch/arm/plat-spear/shirq.c
@@ -0,0 +1,118 @@
+/*
+ * arch/arm/plat-spear/shirq.c
+ *
+ * SPEAr platform shared irq layer source file
+ *
+ * Copyright (C) 2009 ST Microelectronics
+ * Viresh Kumar<viresh.kumar@st.com>
+ *
+ * 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.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/spinlock.h>
+#include <plat/shirq.h>
+
+struct spear_shirq *shirq;
+static DEFINE_SPINLOCK(lock);
+
+static void shirq_irq_mask(unsigned irq)
+{
+ struct spear_shirq *shirq = get_irq_chip_data(irq);
+ u32 val, id = irq - shirq->dev_config[0].virq;
+ unsigned long flags;
+
+ if ((shirq->regs.enb_reg == -1) || shirq->dev_config[id].enb_mask == -1)
+ return;
+
+ spin_lock_irqsave(&lock, flags);
+ val = readl(shirq->regs.base + shirq->regs.enb_reg);
+ if (shirq->regs.reset_to_enb)
+ val |= shirq->dev_config[id].enb_mask;
+ else
+ val &= ~(shirq->dev_config[id].enb_mask);
+ writel(val, shirq->regs.base + shirq->regs.enb_reg);
+ spin_unlock_irqrestore(&lock, flags);
+}
+
+static void shirq_irq_unmask(unsigned irq)
+{
+ struct spear_shirq *shirq = get_irq_chip_data(irq);
+ u32 val, id = irq - shirq->dev_config[0].virq;
+ unsigned long flags;
+
+ if ((shirq->regs.enb_reg == -1) || shirq->dev_config[id].enb_mask == -1)
+ return;
+
+ spin_lock_irqsave(&lock, flags);
+ val = readl(shirq->regs.base + shirq->regs.enb_reg);
+ if (shirq->regs.reset_to_enb)
+ val &= ~(shirq->dev_config[id].enb_mask);
+ else
+ val |= shirq->dev_config[id].enb_mask;
+ writel(val, shirq->regs.base + shirq->regs.enb_reg);
+ spin_unlock_irqrestore(&lock, flags);
+}
+
+static struct irq_chip shirq_chip = {
+ .name = "spear_shirq",
+ .ack = shirq_irq_mask,
+ .mask = shirq_irq_mask,
+ .unmask = shirq_irq_unmask,
+};
+
+static void shirq_handler(unsigned irq, struct irq_desc *desc)
+{
+ u32 i, val, mask;
+ struct spear_shirq *shirq = get_irq_data(irq);
+
+ desc->chip->ack(irq);
+ while ((val = readl(shirq->regs.base + shirq->regs.status_reg) &
+ shirq->regs.status_reg_mask)) {
+ for (i = 0; (i < shirq->dev_count) && val; i++) {
+ if (!(shirq->dev_config[i].status_mask & val))
+ continue;
+
+ generic_handle_irq(shirq->dev_config[i].virq);
+
+ /* clear interrupt */
+ val &= ~shirq->dev_config[i].status_mask;
+ if ((shirq->regs.clear_reg == -1) ||
+ shirq->dev_config[i].clear_mask == -1)
+ continue;
+ mask = readl(shirq->regs.base + shirq->regs.clear_reg);
+ if (shirq->regs.reset_to_clear)
+ mask &= ~shirq->dev_config[i].clear_mask;
+ else
+ mask |= shirq->dev_config[i].clear_mask;
+ writel(mask, shirq->regs.base + shirq->regs.clear_reg);
+ }
+ }
+ desc->chip->unmask(irq);
+}
+
+int spear_shirq_register(struct spear_shirq *shirq)
+{
+ int i;
+
+ if (!shirq || !shirq->dev_config || !shirq->regs.base)
+ return -EFAULT;
+
+ if (!shirq->dev_count)
+ return -EINVAL;
+
+ set_irq_chained_handler(shirq->irq, shirq_handler);
+ for (i = 0; i < shirq->dev_count; i++) {
+ set_irq_chip(shirq->dev_config[i].virq, &shirq_chip);
+ set_irq_handler(shirq->dev_config[i].virq, handle_simple_irq);
+ set_irq_flags(shirq->dev_config[i].virq, IRQF_VALID);
+ set_irq_chip_data(shirq->dev_config[i].virq, shirq);
+ }
+
+ set_irq_data(shirq->irq, shirq);
+ return 0;
+}