[RFC PATCH 07/13] switchtec_ntb: initialize hardware for doorbells and messages

[Logan Gunthorpe <logang@deltatee.com>]

This patch sets up some hardware registers and creates interrupt service
routines for the doorbells and messages.

There are 64 doorbells in the switch that are shared between all
partitions. The upper 4 doorbells are also shared with the messages
and are there for not used. Thus, this code provides 28 doorbells
for each partition.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Stephen Bates <sbates@raithlin.com>
Reviewed-by: Kurt Schwemmer <kurt.schwemmer@microsemi.com>
---
 drivers/ntb/hw/mscc/switchtec_ntb.c | 142 ++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)

diff --git a/drivers/ntb/hw/mscc/switchtec_ntb.c b/drivers/ntb/hw/mscc/switchtec_ntb.c
index 756307d1a8a3..6c9b4e337cdf 100644
--- a/drivers/ntb/hw/mscc/switchtec_ntb.c
+++ b/drivers/ntb/hw/mscc/switchtec_ntb.c
@@ -16,6 +16,7 @@
 #include <linux/switchtec.h>
 #include <linux/module.h>
 #include <linux/delay.h>
+#include <linux/interrupt.h>
 
 MODULE_DESCRIPTION("Microsemi Switchtec(tm) NTB Driver");
 MODULE_VERSION("0.1");
@@ -67,6 +68,9 @@ struct switchtec_ntb {
 	int self_partition;
 	int peer_partition;
 
+	int doorbell_irq;
+	int message_irq;
+
 	struct ntb_info_regs __iomem *mmio_ntb;
 	struct ntb_ctrl_regs __iomem *mmio_ctrl;
 	struct ntb_dbmsg_regs __iomem *mmio_dbmsg;
@@ -78,6 +82,11 @@ struct switchtec_ntb {
 	struct shared_mw __iomem *peer_shared;
 	dma_addr_t self_shared_dma;
 
+	u64 db_mask;
+	u64 db_valid_mask;
+	int db_shift;
+	int db_peer_shift;
+
 	int nr_direct_mw;
 	int nr_lut_mw;
 	int direct_mw_to_bar[MAX_DIRECT_MW];
@@ -180,6 +189,49 @@ static void switchtec_ntb_init_mw(struct switchtec_ntb *sndev)
 		sndev->nr_direct_mw, sndev->nr_lut_mw);
 }
 
+/*
+ * There are 64 doorbells in the switch hardware but this is
+ * shared among all partitions. So we must split them in half
+ * (32 for each partition). However, the message interrupts are
+ * also shared with the top 4 doorbells so we just limit this to
+ * 28 doorbells per partition
+ */
+static void switchtec_ntb_init_db(struct switchtec_ntb *sndev)
+{
+	sndev->db_valid_mask = 0x0FFFFFFF;
+
+	if (sndev->self_partition < sndev->peer_partition) {
+		sndev->db_shift = 0;
+		sndev->db_peer_shift = 32;
+	} else {
+		sndev->db_shift = 32;
+		sndev->db_peer_shift = 0;
+	}
+
+	sndev->db_mask = 0x0FFFFFFFFFFFFFFFULL;
+	iowrite64(~sndev->db_mask, &sndev->mmio_self_dbmsg->idb_mask);
+	iowrite64(sndev->db_valid_mask << sndev->db_peer_shift,
+		  &sndev->mmio_self_dbmsg->odb_mask);
+}
+
+static void switchtec_ntb_init_msgs(struct switchtec_ntb *sndev)
+{
+	int i;
+	u32 msg_map = 0;
+
+	for (i = 0; i < ARRAY_SIZE(sndev->mmio_self_dbmsg->imsg); i++) {
+		int m = i | sndev->peer_partition << 2;
+
+		msg_map |= m << i * 8;
+	}
+
+	iowrite32(msg_map, &sndev->mmio_self_dbmsg->msg_map);
+
+	for (i = 0; i < ARRAY_SIZE(sndev->mmio_self_dbmsg->imsg); i++)
+		iowrite64(NTB_DBMSG_IMSG_STATUS | NTB_DBMSG_IMSG_MASK,
+			  &sndev->mmio_self_dbmsg->imsg[i]);
+}
+
 static int switchtec_ntb_init_req_id_table(struct switchtec_ntb *sndev)
 {
 	int rc = 0;
@@ -300,6 +352,87 @@ static void switchtec_ntb_deinit_shared_mw(struct switchtec_ntb *sndev)
 				  sndev->self_shared_dma);
 }
 
+static irqreturn_t switchtec_ntb_doorbell_isr(int irq, void *dev)
+{
+	struct switchtec_ntb *sndev = dev;
+
+	dev_dbg(&sndev->stdev->dev, "doorbell\n");
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t switchtec_ntb_message_isr(int irq, void *dev)
+{
+	int i;
+	struct switchtec_ntb *sndev = dev;
+
+	for (i = 0; i < ARRAY_SIZE(sndev->mmio_self_dbmsg->imsg); i++) {
+		u64 msg = ioread64(&sndev->mmio_self_dbmsg->imsg[i]);
+
+		if (msg & NTB_DBMSG_IMSG_STATUS) {
+			dev_dbg(&sndev->stdev->dev, "message: %d %08x\n", i,
+				(u32)msg);
+			iowrite8(1, &sndev->mmio_self_dbmsg->imsg[i].status);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int switchtec_ntb_init_db_msg_irq(struct switchtec_ntb *sndev)
+{
+	int i;
+	int rc;
+	int doorbell_irq = 0;
+	int message_irq = 0;
+	int event_irq;
+	int idb_vecs = sizeof(sndev->mmio_self_dbmsg->idb_vec_map);
+
+	event_irq = ioread32(&sndev->stdev->mmio_part_cfg->vep_vector_number);
+
+	while (doorbell_irq == event_irq)
+		doorbell_irq++;
+	while (message_irq == doorbell_irq ||
+	       message_irq == event_irq)
+		message_irq++;
+
+	dev_dbg(&sndev->stdev->dev, "irqs - event: %d, db: %d, msgs: %d",
+		event_irq, doorbell_irq, message_irq);
+
+	for (i = 0; i < idb_vecs - 4; i++)
+		iowrite8(doorbell_irq,
+			 &sndev->mmio_self_dbmsg->idb_vec_map[i]);
+
+	for (; i < idb_vecs; i++)
+		iowrite8(message_irq,
+			 &sndev->mmio_self_dbmsg->idb_vec_map[i]);
+
+	sndev->doorbell_irq = pci_irq_vector(sndev->stdev->pdev, doorbell_irq);
+	sndev->message_irq = pci_irq_vector(sndev->stdev->pdev, message_irq);
+
+	rc = request_irq(sndev->doorbell_irq,
+			 switchtec_ntb_doorbell_isr, 0,
+			 "switchtec_ntb_doorbell", sndev);
+	if (rc)
+		return rc;
+
+	rc = request_irq(sndev->message_irq,
+			 switchtec_ntb_message_isr, 0,
+			 "switchtec_ntb_message", sndev);
+	if (rc) {
+		free_irq(sndev->doorbell_irq, sndev);
+		return rc;
+	}
+
+	return 0;
+}
+
+static void switchtec_ntb_deinit_db_msg_irq(struct switchtec_ntb *sndev)
+{
+	free_irq(sndev->doorbell_irq, sndev);
+	free_irq(sndev->message_irq, sndev);
+}
+
 static int switchtec_ntb_add(struct device *dev,
 			     struct class_interface *class_intf)
 {
@@ -323,6 +456,8 @@ static int switchtec_ntb_add(struct device *dev,
 
 	switchtec_ntb_init_sndev(sndev);
 	switchtec_ntb_init_mw(sndev);
+	switchtec_ntb_init_db(sndev);
+	switchtec_ntb_init_msgs(sndev);
 
 	rc = switchtec_ntb_init_req_id_table(sndev);
 	if (rc)
@@ -332,11 +467,17 @@ static int switchtec_ntb_add(struct device *dev,
 	if (rc)
 		goto free_and_exit;
 
+	rc = switchtec_ntb_init_db_msg_irq(sndev);
+	if (rc)
+		goto deinit_shared_and_exit;
+
 	stdev->sndev = sndev;
 	dev_info(dev, "NTB device registered");
 
 	return 0;
 
+deinit_shared_and_exit:
+	switchtec_ntb_deinit_shared_mw(sndev);
 free_and_exit:
 	kfree(sndev);
 	dev_err(dev, "failed to register ntb device: %d", rc);
@@ -353,6 +494,7 @@ void switchtec_ntb_remove(struct device *dev,
 		return;
 
 	stdev->sndev = NULL;
+	switchtec_ntb_deinit_db_msg_irq(sndev);
 	switchtec_ntb_deinit_shared_mw(sndev);
 	kfree(sndev);
 	dev_info(dev, "ntb device unregistered");
-- 
2.11.0