[PATCH v2 4/5] irqchip:create irq domain for each mbigen device

From: Ma Jun <redacted>

For peripheral devices which connect to mbigen,mbigen is a interrupt
controller. So, we create irq domain for each mbigen device and add
mbigen irq domain into irq hierarchy structure.

Signed-off-by: Ma Jun <redacted>
---
 drivers/irqchip/irq-mbigen-v1.c |  136 +++++++++++++++++++++++++++++++++++++++
 1 files changed, 136 insertions(+), 0 deletions(-)

diff --git a/drivers/irqchip/irq-mbigen-v1.c b/drivers/irqchip/irq-mbigen-v1.c
index 9445658..61e7ad0 100644
--- a/drivers/irqchip/irq-mbigen-v1.c
+++ b/drivers/irqchip/irq-mbigen-v1.c

@@ -16,11 +16,30 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/interrupt.h>
+#include <linux/irqchip.h>
 #include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 
+/* The maximum IRQ pin number of mbigen chip(start from 0) */
+#define MAXIMUM_IRQ_PIN_NUM		640
+
+/**
+ * In mbigen vector register
+ * bit[31:16]:	device id
+ * bit[15:0]:	event id value
+ */
+#define IRQ_EVENT_ID_MASK		0xffff
+
+/* offset of vector register in mbigen node */
+#define REG_MBIGEN_VEC_OFFSET		0x300
+#define REG_MBIGEN_EXT_VEC_OFFSET		0x320
+
 /**
  * struct mbigen_device - holds the information of mbigen device.
  *

@@ -32,10 +51,112 @@ struct mbigen_device {
 	void __iomem		*base;
 };
 
+static int get_mbigen_nid(unsigned int offset)
+{
+	int nid = 0;
+
+	if (offset < 256)
+		nid = offset / 64;
+	else if (offset < 384)
+		nid = 4;
+	else if (offset < 640)
+		nid = 5;
+
+	return nid;
+}
+
+static inline unsigned int get_mbigen_vec_reg(irq_hw_number_t hwirq)
+{
+	unsigned int nid;
+
+	nid = get_mbigen_nid(hwirq);
+
+	if (nid < 4)
+		return (nid * 4) + REG_MBIGEN_VEC_OFFSET;
+	else
+		return (nid - 4) * 4 + REG_MBIGEN_EXT_VEC_OFFSET;
+}
+
+static struct irq_chip mbigen_irq_chip = {
+	.name =			"mbigen-v1",
+};
+
+static void mbigen_write_msg(struct msi_desc *desc, struct msi_msg *msg)
+{
+	/* The address of doorbell is encoded in mbigen register by default
+	 * So,we don't need to program the doorbell address at here
+	 * Besides, the event ID is decided by the hardware pin number,
+	 * we can't change it in software.So, we don't need to encode the
+	 * event ID in mbigen register.
+	 */