[dpdk-dev] [PATCH v3 2/2] common/octeontx2: add polling based response mbox message

[Sunil Kumar Kori]

Currently otx2_mbox_get_rsp_xxx get response once AF driver
interrupts after completion. But this funciton will get into
deadlock if called in another interrupt context.

To avoid it, implemented another version of this function which polls
on dedicated memory for a given timeout.

Also after clearing interrupt, there could UP messages available for
processing. So irq handler must check mbox messages.

Signed-off-by: Sunil Kumar Kori <skori at marvell.com>
Signed-off-by: Harman Kalra <hkalra at marvell.com>
---
v3:
 - Remove experimental tag as API is defined static.
 - Merge all changes to single patch.
v2:
 - Included Makefile and meson build changes.
 - Rebased patch on 19.11-rc4

 drivers/common/octeontx2/otx2_dev.c  | 41 ++++++++++----------
 drivers/common/octeontx2/otx2_mbox.c | 57 +++++++++++++++++++++++-----
 drivers/common/octeontx2/otx2_mbox.h |  5 ++-
 3 files changed, 72 insertions(+), 31 deletions(-)

diff --git a/drivers/common/octeontx2/otx2_dev.c b/drivers/common/octeontx2/otx2_dev.c
index 0fc799e4a..d61c712fa 100644
--- a/drivers/common/octeontx2/otx2_dev.c
+++ b/drivers/common/octeontx2/otx2_dev.c
@@ -577,17 +577,16 @@ otx2_pf_vf_mbox_irq(void *param)
 
 	intr = otx2_read64(dev->bar2 + RVU_VF_INT);
 	if (intr == 0)
-		return;
+		otx2_base_dbg("Proceeding to check mbox UP messages if any");
 
 	otx2_write64(intr, dev->bar2 + RVU_VF_INT);
 	otx2_base_dbg("Irq 0x%" PRIx64 "(pf:%d,vf:%d)", intr, dev->pf, dev->vf);
-	if (intr) {
-		/* First process all configuration messages */
-		otx2_process_msgs(dev, dev->mbox);
 
-		/* Process Uplink messages */
-		otx2_process_msgs_up(dev, &dev->mbox_up);
-	}
+	/* First process all configuration messages */
+	otx2_process_msgs(dev, dev->mbox);
+
+	/* Process Uplink messages */
+	otx2_process_msgs_up(dev, &dev->mbox_up);
 }
 
 static void
@@ -598,18 +597,16 @@ otx2_af_pf_mbox_irq(void *param)
 
 	intr = otx2_read64(dev->bar2 + RVU_PF_INT);
 	if (intr == 0)
-		return;
+		otx2_base_dbg("Proceeding to check mbox UP messages if any");
 
 	otx2_write64(intr, dev->bar2 + RVU_PF_INT);
-
 	otx2_base_dbg("Irq 0x%" PRIx64 "(pf:%d,vf:%d)", intr, dev->pf, dev->vf);
-	if (intr) {
-		/* First process all configuration messages */
-		otx2_process_msgs(dev, dev->mbox);
 
-		/* Process Uplink messages */
-		otx2_process_msgs_up(dev, &dev->mbox_up);
-	}
+	/* First process all configuration messages */
+	otx2_process_msgs(dev, dev->mbox);
+
+	/* Process Uplink messages */
+	otx2_process_msgs_up(dev, &dev->mbox_up);
 }
 
 static int
@@ -900,6 +897,7 @@ otx2_dev_priv_init(struct rte_pci_device *pci_dev, void *otx2_dev)
 {
 	int up_direction = MBOX_DIR_PFAF_UP;
 	int rc, direction = MBOX_DIR_PFAF;
+	uint64_t intr_offset = RVU_PF_INT;
 	struct otx2_dev *dev = otx2_dev;
 	uintptr_t bar2, bar4;
 	uint64_t bar4_addr;
@@ -924,15 +922,18 @@ otx2_dev_priv_init(struct rte_pci_device *pci_dev, void *otx2_dev)
 	if (otx2_dev_is_vf(dev)) {
 		direction = MBOX_DIR_VFPF;
 		up_direction = MBOX_DIR_VFPF_UP;
+		intr_offset = RVU_VF_INT;
 	}
 
 	/* Initialize the local mbox */
-	rc = otx2_mbox_init(&dev->mbox_local, bar4, bar2, direction, 1);
+	rc = otx2_mbox_init(&dev->mbox_local, bar4, bar2, direction, 1,
+			    intr_offset);
 	if (rc)
 		goto error;
 	dev->mbox = &dev->mbox_local;
 
-	rc = otx2_mbox_init(&dev->mbox_up, bar4, bar2, up_direction, 1);
+	rc = otx2_mbox_init(&dev->mbox_up, bar4, bar2, up_direction, 1,
+			    intr_offset);
 	if (rc)
 		goto error;
 
@@ -967,13 +968,15 @@ otx2_dev_priv_init(struct rte_pci_device *pci_dev, void *otx2_dev)
 		}
 		/* Init mbox object */
 		rc = otx2_mbox_init(&dev->mbox_vfpf, (uintptr_t)hwbase,
-				    bar2, MBOX_DIR_PFVF, pci_dev->max_vfs);
+				    bar2, MBOX_DIR_PFVF, pci_dev->max_vfs,
+				    intr_offset);
 		if (rc)
 			goto iounmap;
 
 		/* PF -> VF UP messages */
 		rc = otx2_mbox_init(&dev->mbox_vfpf_up, (uintptr_t)hwbase,
-				    bar2, MBOX_DIR_PFVF_UP, pci_dev->max_vfs);
+				    bar2, MBOX_DIR_PFVF_UP, pci_dev->max_vfs,
+				    intr_offset);
 		if (rc)
 			goto mbox_fini;
 	}
diff --git a/drivers/common/octeontx2/otx2_mbox.c b/drivers/common/octeontx2/otx2_mbox.c
index c359bf42f..f07f07918 100644
--- a/drivers/common/octeontx2/otx2_mbox.c
+++ b/drivers/common/octeontx2/otx2_mbox.c
@@ -11,6 +11,7 @@
 #include <rte_cycles.h>
 
 #include "otx2_mbox.h"
+#include "otx2_dev.h"
 
 #define RVU_AF_AFPF_MBOX0	(0x02000)
 #define RVU_AF_AFPF_MBOX1	(0x02008)
@@ -59,12 +60,13 @@ otx2_mbox_reset(struct otx2_mbox *mbox, int devid)
 }
 
 int
-otx2_mbox_init(struct otx2_mbox *mbox, uintptr_t hwbase,
-	       uintptr_t reg_base, int direction, int ndevs)
+otx2_mbox_init(struct otx2_mbox *mbox, uintptr_t hwbase, uintptr_t reg_base,
+	       int direction, int ndevs, uint64_t intr_offset)
 {
 	struct otx2_mbox_dev *mdev;
 	int devid;
 
+	mbox->intr_offset = intr_offset;
 	mbox->reg_base = reg_base;
 	mbox->hwbase = hwbase;
 
@@ -230,8 +232,8 @@ otx2_mbox_get_rsp(struct otx2_mbox *mbox, int devid, void **msg)
 	int rc;
 
 	rc = otx2_mbox_wait_for_rsp(mbox, devid);
-	if (rc != 1)
-		return -EIO;
+	if (rc < 0)
+		return rc;
 
 	rte_rmb();
 
@@ -244,6 +246,37 @@ otx2_mbox_get_rsp(struct otx2_mbox *mbox, int devid, void **msg)
 	return msghdr->rc;
 }
 
+/**
+ * Polling for given wait time to get mailbox response
+ */
+static int
+mbox_poll(struct otx2_mbox *mbox, uint32_t wait)
+{
+	uint32_t timeout = 0, sleep = 1;
+	uint64_t rsp_reg = 0;
+	uintptr_t reg_addr;
+
+	reg_addr = mbox->reg_base + mbox->intr_offset;
+	while (!rsp_reg) {
+		rte_rmb();
+		rsp_reg = otx2_read64(reg_addr);
+
+		if (timeout >= wait)
+			return -ETIMEDOUT;
+
+		rte_delay_us(sleep);
+		timeout += sleep;
+	}
+
+	/* Clear interrupt */
+	otx2_write64(rsp_reg, reg_addr);
+
+	/* Reset mbox */
+	otx2_mbox_reset(mbox, 0);
+
+	return 0;
+}
+
 /**
  * @internal
  * Wait and get mailbox response with timeout
@@ -258,8 +291,8 @@ otx2_mbox_get_rsp_tmo(struct otx2_mbox *mbox, int devid, void **msg,
 	int rc;
 
 	rc = otx2_mbox_wait_for_rsp_tmo(mbox, devid, tmo);
-	if (rc != 1)
-		return -EIO;
+	if (rc < 0)
+		return rc;
 
 	rte_rmb();
 
@@ -321,11 +354,15 @@ otx2_mbox_wait_for_rsp_tmo(struct otx2_mbox *mbox, int devid, uint32_t tmo)
 	}
 
 	/* Wait message */
-	rc = mbox_wait(mbox, devid, tmo);
-	if (rc)
-		return rc;
+	if (rte_thread_is_intr()) {
+		rc = mbox_poll(mbox, tmo);
+	} else {
+		rc = mbox_wait(mbox, devid, tmo);
+		if (!rc)
+			rc = mdev->msgs_acked;
+	}
 
-	return mdev->msgs_acked;
+	return rc;
 }
 
 /**
diff --git a/drivers/common/octeontx2/otx2_mbox.h b/drivers/common/octeontx2/otx2_mbox.h
index e0e4e2f63..0535cec36 100644
--- a/drivers/common/octeontx2/otx2_mbox.h
+++ b/drivers/common/octeontx2/otx2_mbox.h
@@ -73,6 +73,7 @@ struct otx2_mbox {
 	uint16_t tx_size;  /* Size of Tx region */
 	uint16_t ndevs;    /* The number of peers */
 	struct otx2_mbox_dev *dev;
+	uint64_t intr_offset; /* Offset to interrupt register */
 };
 
 /* Header which precedes all mbox messages */
@@ -1562,8 +1563,8 @@ struct tim_enable_rsp {
 const char *otx2_mbox_id2name(uint16_t id);
 int otx2_mbox_id2size(uint16_t id);
 void otx2_mbox_reset(struct otx2_mbox *mbox, int devid);
-int otx2_mbox_init(struct otx2_mbox *mbox, uintptr_t hwbase,
-		   uintptr_t reg_base, int direction, int ndevs);
+int otx2_mbox_init(struct otx2_mbox *mbox, uintptr_t hwbase, uintptr_t reg_base,
+		   int direction, int ndevsi, uint64_t intr_offset);
 void otx2_mbox_fini(struct otx2_mbox *mbox);
 void otx2_mbox_msg_send(struct otx2_mbox *mbox, int devid);
 int otx2_mbox_wait_for_rsp(struct otx2_mbox *mbox, int devid);
-- 
2.17.1