[PATCH RFC 10/15] dmaengine: idxd: add config support for readonly devices

[Dave Jiang]

The device can have a readonly bit set for configuration. This especially
is true for mediated device in guest that are software emulated. Add
support to load configuration if the device config is read only.

Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
 drivers/dma/idxd/device.c |  159 ++++++++++++++++++++++++++++++++++++++++++++-
 drivers/dma/idxd/idxd.h   |    2 +
 drivers/dma/idxd/init.c   |    6 ++
 drivers/dma/idxd/sysfs.c  |   45 +++++++++----
 4 files changed, 194 insertions(+), 18 deletions(-)

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 684a0e167770..a46b6558984c 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -603,6 +603,36 @@ static int idxd_groups_config_write(struct idxd_device *idxd)
 	return 0;
 }
 
+static int idxd_wq_config_write_ro(struct idxd_wq *wq)
+{
+	struct idxd_device *idxd = wq->idxd;
+	int wq_offset;
+
+	if (!wq->group)
+		return 0;
+
+	if (idxd->pasid_enabled) {
+		wq->wqcfg.pasid_en = 1;
+		if (wq->type == IDXD_WQT_KERNEL && wq_dedicated(wq))
+			wq->wqcfg.pasid = idxd->pasid;
+	} else {
+		wq->wqcfg.pasid_en = 0;
+	}
+
+	if (wq->type == IDXD_WQT_KERNEL)
+		wq->wqcfg.priv = 1;
+
+	if (idxd->type == IDXD_TYPE_DSA &&
+	    idxd->hw.gen_cap.block_on_fault &&
+	    test_bit(WQ_FLAG_BOF, &wq->flags))
+		wq->wqcfg.bof = 1;
+
+	wq_offset = idxd->wqcfg_offset + wq->id * 32 + 2 * sizeof(u32);
+	iowrite32(wq->wqcfg.bits[2], idxd->reg_base + wq_offset);
+
+	return 0;
+}
+
 static int idxd_wq_config_write(struct idxd_wq *wq)
 {
 	struct idxd_device *idxd = wq->idxd;
@@ -633,7 +663,8 @@ static int idxd_wq_config_write(struct idxd_wq *wq)
 
 	if (idxd->pasid_enabled) {
 		wq->wqcfg.pasid_en = 1;
-		wq->wqcfg.pasid = idxd->pasid;
+		if (wq->type == IDXD_WQT_KERNEL && wq_dedicated(wq))
+			wq->wqcfg.pasid = idxd->pasid;
 	}
 
 	wq->wqcfg.priority = wq->priority;
@@ -658,14 +689,17 @@ static int idxd_wq_config_write(struct idxd_wq *wq)
 	return 0;
 }
 
-static int idxd_wqs_config_write(struct idxd_device *idxd)
+static int idxd_wqs_config_write(struct idxd_device *idxd, bool rw)
 {
 	int i, rc;
 
 	for (i = 0; i < idxd->max_wqs; i++) {
 		struct idxd_wq *wq = &idxd->wqs[i];
 
-		rc = idxd_wq_config_write(wq);
+		if (rw)
+			rc = idxd_wq_config_write(wq);
+		else
+			rc = idxd_wq_config_write_ro(wq);
 		if (rc < 0)
 			return rc;
 	}
@@ -764,6 +798,12 @@ static int idxd_wqs_setup(struct idxd_device *idxd)
 	return 0;
 }
 
+int idxd_device_ro_config(struct idxd_device *idxd)
+{
+	lockdep_assert_held(&idxd->dev_lock);
+	return idxd_wqs_config_write(idxd, false);
+}
+
 int idxd_device_config(struct idxd_device *idxd)
 {
 	int rc;
@@ -779,7 +819,7 @@ int idxd_device_config(struct idxd_device *idxd)
 
 	idxd_group_flags_setup(idxd);
 
-	rc = idxd_wqs_config_write(idxd);
+	rc = idxd_wqs_config_write(idxd, true);
 	if (rc < 0)
 		return rc;
 
@@ -789,3 +829,114 @@ int idxd_device_config(struct idxd_device *idxd)
 
 	return 0;
 }
+
+static void idxd_wq_load_config(struct idxd_wq *wq)
+{
+	struct idxd_device *idxd = wq->idxd;
+	struct device *dev = &idxd->pdev->dev;
+	int wqcfg_offset;
+	int i;
+
+	wqcfg_offset = idxd->wqcfg_offset + wq->id * 32;
+	memcpy_fromio(&wq->wqcfg, idxd->reg_base + wqcfg_offset,
+		      sizeof(union wqcfg));
+
+	wq->size = wq->wqcfg.wq_size;
+	wq->threshold = wq->wqcfg.wq_thresh;
+	if (wq->wqcfg.priv)
+		wq->type = IDXD_WQT_KERNEL;
+
+	if (wq->wqcfg.mode)
+		set_bit(WQ_FLAG_DEDICATED, &wq->flags);
+
+	wq->priority = wq->wqcfg.priority;
+
+	if (wq->wqcfg.bof)
+		set_bit(WQ_FLAG_BOF, &wq->flags);
+
+	if (idxd->pasid_enabled) {
+		wq->wqcfg.pasid_en = 1;
+		wqcfg_offset = idxd->wqcfg_offset +
+			       wq->id * 32 + 2 * sizeof(u32);
+		iowrite32(wq->wqcfg.bits[2], idxd->reg_base + wqcfg_offset);
+	}
+
+	for (i = 0; i < 8; i++) {
+		wqcfg_offset = idxd->wqcfg_offset +
+			       wq->id * 32 + i * sizeof(u32);
+		dev_dbg(dev, "WQ[%d][%d][%#x]: %#x\n",
+			wq->id, i, wqcfg_offset, wq->wqcfg.bits[i]);
+	}
+}
+
+static void idxd_group_load_config(struct idxd_group *group)
+{
+	struct idxd_device *idxd = group->idxd;
+	struct device *dev = &idxd->pdev->dev;
+	int i, j, grpcfg_offset;
+
+	/* load wqs */
+	for (i = 0; i < 4; i++) {
+		struct idxd_wq *wq;
+
+		grpcfg_offset = idxd->grpcfg_offset +
+				group->id * 64 + i * sizeof(u64);
+		group->grpcfg.wqs[i] =
+			ioread64(idxd->reg_base + grpcfg_offset);
+		dev_dbg(dev, "GRPCFG wq[%d:%d: %#x]: %#llx\n",
+			group->id, i, grpcfg_offset,
+			group->grpcfg.wqs[i]);
+
+		for (j = 0; j < sizeof(u64); j++) {
+			int wq_id = i * 64 + j;
+
+			if (wq_id >= idxd->max_wqs)
+				break;
+			if (group->grpcfg.wqs[i] & BIT(j)) {
+				wq = &idxd->wqs[wq_id];
+				wq->group = group;
+			}
+		}
+	}
+
+	grpcfg_offset = idxd->grpcfg_offset + group->id * 64 + 32;
+	group->grpcfg.engines = ioread64(idxd->reg_base + grpcfg_offset);
+	dev_dbg(dev, "GRPCFG engs[%d: %#x]: %#llx\n", group->id,
+		grpcfg_offset, group->grpcfg.engines);
+
+	for (i = 0; i < sizeof(u64); i++) {
+		if (i > idxd->max_engines)
+			break;
+		if (group->grpcfg.engines & BIT(i)) {
+			struct idxd_engine *engine = &idxd->engines[i];
+
+			engine->group = group;
+		}
+	}
+
+	grpcfg_offset = grpcfg_offset + group->id * 64 + 40;
+	group->grpcfg.flags.bits = ioread32(idxd->reg_base + grpcfg_offset);
+	dev_dbg(dev, "GRPFLAGS flags[%d: %#x]: %#x\n",
+		group->id, grpcfg_offset, group->grpcfg.flags.bits);
+}
+
+void idxd_device_load_config(struct idxd_device *idxd)
+{
+	union gencfg_reg reg;
+	int i;
+
+	reg.bits = ioread32(idxd->reg_base + IDXD_GENCFG_OFFSET);
+	idxd->token_limit = reg.token_limit;
+
+	for (i = 0; i < idxd->max_groups; i++) {
+		struct idxd_group *group = &idxd->groups[i];
+
+		idxd_group_load_config(group);
+	}
+
+	for (i = 0; i < idxd->max_wqs; i++) {
+		struct idxd_wq *wq = &idxd->wqs[i];
+
+		idxd_wq_load_config(wq);
+	}
+}
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 304b76169c0d..82a9b6035722 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -286,8 +286,10 @@ int idxd_device_reset(struct idxd_device *idxd);
 int __idxd_device_reset(struct idxd_device *idxd);
 void idxd_device_cleanup(struct idxd_device *idxd);
 int idxd_device_config(struct idxd_device *idxd);
+int idxd_device_ro_config(struct idxd_device *idxd);
 void idxd_device_wqs_clear_state(struct idxd_device *idxd);
 int idxd_device_drain_pasid(struct idxd_device *idxd, int pasid);
+void idxd_device_load_config(struct idxd_device *idxd);
 
 /* work queue control */
 int idxd_wq_alloc_resources(struct idxd_wq *wq);
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index f794ee1c7c1b..c0fd796e9dce 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -367,6 +367,12 @@ static int idxd_probe(struct idxd_device *idxd)
 	if (rc)
 		goto err_setup;
 
+	/* If the configs are readonly, then load them from device */
+	if (!test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) {
+		dev_dbg(dev, "Loading RO device config\n");
+		idxd_device_load_config(idxd);
+	}
+
 	rc = idxd_setup_interrupts(idxd);
 	if (rc)
 		goto err_setup;
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index dc38172be42e..1dd3ade2e438 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -120,13 +120,17 @@ static int idxd_config_bus_probe(struct device *dev)
 
 		spin_lock_irqsave(&idxd->dev_lock, flags);
 
-		/* Perform IDXD configuration and enabling */
-		rc = idxd_device_config(idxd);
-		if (rc < 0) {
-			spin_unlock_irqrestore(&idxd->dev_lock, flags);
-			module_put(THIS_MODULE);
-			dev_warn(dev, "Device config failed: %d\n", rc);
-			return rc;
+		if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) {
+			/* Perform DSA configuration and enabling */
+			rc = idxd_device_config(idxd);
+			if (rc < 0) {
+				spin_unlock_irqrestore(&idxd->dev_lock,
+						       flags);
+				module_put(THIS_MODULE);
+				dev_warn(dev, "Device config failed: %d\n",
+					 rc);
+				return rc;
+			}
 		}
 
 		/* start device */
@@ -211,13 +215,26 @@ static int idxd_config_bus_probe(struct device *dev)
 		}
 
 		spin_lock_irqsave(&idxd->dev_lock, flags);
-		rc = idxd_device_config(idxd);
-		if (rc < 0) {
-			spin_unlock_irqrestore(&idxd->dev_lock, flags);
-			mutex_unlock(&wq->wq_lock);
-			dev_warn(dev, "Writing WQ %d config failed: %d\n",
-				 wq->id, rc);
-			return rc;
+		if (test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags)) {
+			rc = idxd_device_config(idxd);
+			if (rc < 0) {
+				spin_unlock_irqrestore(&idxd->dev_lock,
+						       flags);
+				mutex_unlock(&wq->wq_lock);
+				dev_warn(dev, "Writing WQ %d config failed: %d\n",
+					 wq->id, rc);
+				return rc;
+			}
+		} else {
+			rc = idxd_device_ro_config(idxd);
+			if (rc < 0) {
+				spin_unlock_irqrestore(&idxd->dev_lock,
+						       flags);
+				mutex_unlock(&wq->wq_lock);
+				dev_warn(dev, "Writing WQ %d config failed: %d\n",
+					 wq->id, rc);
+				return rc;
+			}
 		}
 
 		rc = idxd_wq_enable(wq);