MIPS: Add support for Texas Instruments AR7 System-on-a-Chip

This patch adds support for the Texas Instruments AR7 System-on-a-Chip.
It supports the TNETD7100, 7200 and 7300 versions of the SoC.

Signed-off-by: Matteo Croce <matteo@openwrt.org>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Eugene Konev <ejka@openwrt.org>
Signed-off-by: Nicolas Thill <nico@openwrt.org>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 176 insertions, 0 deletions

diff --git a/arch/mips/ar7/irq.c b/arch/mips/ar7/irq.c
new file mode 100644
index 0000000..c781556
--- /dev/null
+++ b/arch/mips/ar7/irq.c
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2006,2007 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2006,2007 Eugene Konev <ejka@openwrt.org>
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+
+#include <asm/irq_cpu.h>
+#include <asm/mipsregs.h>
+#include <asm/mach-ar7/ar7.h>
+
+#define EXCEPT_OFFSET	0x80
+#define PACE_OFFSET	0xA0
+#define CHNLS_OFFSET	0x200
+
+#define REG_OFFSET(irq, reg)	((irq) / 32 * 0x4 + reg * 0x10)
+#define SEC_REG_OFFSET(reg)	(EXCEPT_OFFSET + reg * 0x8)
+#define SEC_SR_OFFSET		(SEC_REG_OFFSET(0))	/* 0x80 */
+#define CR_OFFSET(irq)		(REG_OFFSET(irq, 1))	/* 0x10 */
+#define SEC_CR_OFFSET		(SEC_REG_OFFSET(1))	/* 0x88 */
+#define ESR_OFFSET(irq)		(REG_OFFSET(irq, 2))	/* 0x20 */
+#define SEC_ESR_OFFSET		(SEC_REG_OFFSET(2))	/* 0x90 */
+#define ECR_OFFSET(irq)		(REG_OFFSET(irq, 3))	/* 0x30 */
+#define SEC_ECR_OFFSET		(SEC_REG_OFFSET(3))	/* 0x98 */
+#define PIR_OFFSET		(0x40)
+#define MSR_OFFSET		(0x44)
+#define PM_OFFSET(irq)		(REG_OFFSET(irq, 5))	/* 0x50 */
+#define TM_OFFSET(irq)		(REG_OFFSET(irq, 6))	/* 0x60 */
+
+#define REG(addr) ((u32 *)(KSEG1ADDR(AR7_REGS_IRQ) + addr))
+
+#define CHNL_OFFSET(chnl) (CHNLS_OFFSET + (chnl * 4))
+
+static int ar7_irq_base;
+
+static void ar7_unmask_irq(unsigned int irq)
+{
+	writel(1 << ((irq - ar7_irq_base) % 32),
+	       REG(ESR_OFFSET(irq - ar7_irq_base)));
+}
+
+static void ar7_mask_irq(unsigned int irq)
+{
+	writel(1 << ((irq - ar7_irq_base) % 32),
+	       REG(ECR_OFFSET(irq - ar7_irq_base)));
+}
+
+static void ar7_ack_irq(unsigned int irq)
+{
+	writel(1 << ((irq - ar7_irq_base) % 32),
+	       REG(CR_OFFSET(irq - ar7_irq_base)));
+}
+
+static void ar7_unmask_sec_irq(unsigned int irq)
+{
+	writel(1 << (irq - ar7_irq_base - 40), REG(SEC_ESR_OFFSET));
+}
+
+static void ar7_mask_sec_irq(unsigned int irq)
+{
+	writel(1 << (irq - ar7_irq_base - 40), REG(SEC_ECR_OFFSET));
+}
+
+static void ar7_ack_sec_irq(unsigned int irq)
+{
+	writel(1 << (irq - ar7_irq_base - 40), REG(SEC_CR_OFFSET));
+}
+
+static struct irq_chip ar7_irq_type = {
+	.name = "AR7",
+	.unmask = ar7_unmask_irq,
+	.mask = ar7_mask_irq,
+	.ack = ar7_ack_irq
+};
+
+static struct irq_chip ar7_sec_irq_type = {
+	.name = "AR7",
+	.unmask = ar7_unmask_sec_irq,
+	.mask = ar7_mask_sec_irq,
+	.ack = ar7_ack_sec_irq,
+};
+
+static struct irqaction ar7_cascade_action = {
+	.handler = no_action,
+	.name = "AR7 cascade interrupt"
+};
+
+static void __init ar7_irq_init(int base)
+{
+	int i;
+	/*
+	 * Disable interrupts and clear pending
+	 */
+	writel(0xffffffff, REG(ECR_OFFSET(0)));
+	writel(0xff, REG(ECR_OFFSET(32)));
+	writel(0xffffffff, REG(SEC_ECR_OFFSET));
+	writel(0xffffffff, REG(CR_OFFSET(0)));
+	writel(0xff, REG(CR_OFFSET(32)));
+	writel(0xffffffff, REG(SEC_CR_OFFSET));
+
+	ar7_irq_base = base;
+
+	for (i = 0; i < 40; i++) {
+		writel(i, REG(CHNL_OFFSET(i)));
+		/* Primary IRQ's */
+		set_irq_chip_and_handler(base + i, &ar7_irq_type,
+					 handle_level_irq);
+		/* Secondary IRQ's */
+		if (i < 32)
+			set_irq_chip_and_handler(base + i + 40,
+						 &ar7_sec_irq_type,
+						 handle_level_irq);
+	}
+
+	setup_irq(2, &ar7_cascade_action);
+	setup_irq(ar7_irq_base, &ar7_cascade_action);
+	set_c0_status(IE_IRQ0);
+}
+
+void __init arch_init_irq(void)
+{
+	mips_cpu_irq_init();
+	ar7_irq_init(8);
+}
+
+static void ar7_cascade(void)
+{
+	u32 status;
+	int i, irq;
+
+	/* Primary IRQ's */
+	irq = readl(REG(PIR_OFFSET)) & 0x3f;
+	if (irq) {
+		do_IRQ(ar7_irq_base + irq);
+		return;
+	}
+
+	/* Secondary IRQ's are cascaded through primary '0' */
+	writel(1, REG(CR_OFFSET(irq)));
+	status = readl(REG(SEC_SR_OFFSET));
+	for (i = 0; i < 32; i++) {
+		if (status & 1) {
+			do_IRQ(ar7_irq_base + i + 40);
+			return;
+		}
+		status >>= 1;
+	}
+
+	spurious_interrupt();
+}
+
+asmlinkage void plat_irq_dispatch(void)
+{
+	unsigned int pending = read_c0_status() & read_c0_cause() & ST0_IM;
+	if (pending & STATUSF_IP7)		/* cpu timer */
+		do_IRQ(7);
+	else if (pending & STATUSF_IP2)		/* int0 hardware line */
+		ar7_cascade();
+	else
+		spurious_interrupt();
+}