Certain DSA 3.0 opcodes, such as Gather copy and Gather reduce, require max
SGL configured for workqueues prior to supporting these opcodes.

Configure the maximum scatter-gather list (SGL) size for workqueues during
setup on the supported HW. Application can then properly handle the SGL
size without explicitly setting it.

Signed-off-by: Yi Sun <yi.sun@intel.com>
Co-developed-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Tested-by: Yi Lai <yi1.lai@intel.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 5cf419fe6b46..1c10b030bea7 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -375,6 +375,7 @@ static void idxd_wq_disable_cleanup(struct idxd_wq *wq)
 	memset(wq->name, 0, WQ_NAME_SIZE);
 	wq->max_xfer_bytes = WQ_DEFAULT_MAX_XFER;
 	idxd_wq_set_max_batch_size(idxd->data->type, wq, WQ_DEFAULT_MAX_BATCH);
+	idxd_wq_set_init_max_sgl_size(idxd, wq);
 	if (wq->opcap_bmap)
 		bitmap_copy(wq->opcap_bmap, idxd->opcap_bmap, IDXD_MAX_OPCAP_BITS);
 }
@@ -974,6 +975,8 @@ static int idxd_wq_config_write(struct idxd_wq *wq)
 	/* bytes 12-15 */
 	wq->wqcfg->max_xfer_shift = ilog2(wq->max_xfer_bytes);
 	idxd_wqcfg_set_max_batch_shift(idxd->data->type, wq->wqcfg, ilog2(wq->max_batch_size));
+	if (idxd_sgl_supported(idxd))
+		wq->wqcfg->max_sgl_shift = ilog2(wq->max_sgl_size);
 
 	/* bytes 32-63 */
 	if (idxd->hw.wq_cap.op_config && wq->opcap_bmap) {
@@ -1152,6 +1155,8 @@ static int idxd_wq_load_config(struct idxd_wq *wq)
 
 	wq->max_xfer_bytes = 1ULL << wq->wqcfg->max_xfer_shift;
 	idxd_wq_set_max_batch_size(idxd->data->type, wq, 1U << wq->wqcfg->max_batch_shift);
+	if (idxd_sgl_supported(idxd))
+		wq->max_sgl_size = 1U << wq->wqcfg->max_sgl_shift;
 
 	for (i = 0; i < WQCFG_STRIDES(idxd); i++) {
 		wqcfg_offset = WQCFG_OFFSET(idxd, wq->id, i);
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index cc0a3fe1c957..ea8c4daed38d 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -227,6 +227,7 @@ struct idxd_wq {
 	char name[WQ_NAME_SIZE + 1];
 	u64 max_xfer_bytes;
 	u32 max_batch_size;
+	u32 max_sgl_size;
 
 	/* Lock to protect upasid_xa access. */
 	struct mutex uc_lock;
@@ -348,6 +349,7 @@ struct idxd_device {
 
 	u64 max_xfer_bytes;
 	u32 max_batch_size;
+	u32 max_sgl_size;
 	int max_groups;
 	int max_engines;
 	int max_rdbufs;
@@ -692,6 +694,20 @@ static inline void idxd_wq_set_max_batch_size(int idxd_type, struct idxd_wq *wq,
 		wq->max_batch_size = max_batch_size;
 }
 
+static bool idxd_sgl_supported(struct idxd_device *idxd)
+{
+	return idxd->data->type == IDXD_TYPE_DSA &&
+	       idxd->hw.version >= DEVICE_VERSION_3 &&
+	       idxd->hw.dsacap0.sgl_formats;
+}
+
+static inline void idxd_wq_set_init_max_sgl_size(struct idxd_device *idxd,
+						 struct idxd_wq *wq)
+{
+	if (idxd_sgl_supported(idxd))
+		wq->max_sgl_size = 1U << idxd->hw.dsacap0.max_sgl_shift;
+}
+
 static inline void idxd_wqcfg_set_max_batch_shift(int idxd_type, union wqcfg *wqcfg,
 						  u32 max_batch_shift)
 {
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 084df60d407b..395d5486aee6 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -217,6 +217,7 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
 		init_completion(&wq->wq_resurrect);
 		wq->max_xfer_bytes = WQ_DEFAULT_MAX_XFER;
 		idxd_wq_set_max_batch_size(idxd->data->type, wq, WQ_DEFAULT_MAX_BATCH);
+		idxd_wq_set_init_max_sgl_size(idxd, wq);
 		wq->enqcmds_retries = IDXD_ENQCMDS_RETRIES;
 		wq->wqcfg = kzalloc_node(idxd->wqcfg_size, GFP_KERNEL, dev_to_node(dev));
 		if (!wq->wqcfg) {
@@ -587,6 +588,10 @@ static void idxd_read_caps(struct idxd_device *idxd)
 		idxd->hw.dsacap1.bits = ioread64(idxd->reg_base + IDXD_DSACAP1_OFFSET);
 		idxd->hw.dsacap2.bits = ioread64(idxd->reg_base + IDXD_DSACAP2_OFFSET);
 	}
+	if (idxd_sgl_supported(idxd)) {
+		idxd->max_sgl_size = 1U << idxd->hw.dsacap0.max_sgl_shift;
+		dev_dbg(dev, "max sgl size: %u\n", idxd->max_sgl_size);
+	}
 
 	/* read iaa cap */
 	if (idxd->data->type == IDXD_TYPE_IAX && idxd->hw.version >= DEVICE_VERSION_2)
diff --git a/drivers/dma/idxd/registers.h b/drivers/dma/idxd/registers.h
index 439bbc311591..c5f344c55a69 100644
--- a/drivers/dma/idxd/registers.h
+++ b/drivers/dma/idxd/registers.h
@@ -385,7 +385,8 @@ union wqcfg {
 		/* bytes 12-15 */
 		u32 max_xfer_shift:5;
 		u32 max_batch_shift:4;
-		u32 rsvd4:23;
+		u32 max_sgl_shift:4;
+		u32 rsvd4:19;
 
 		/* bytes 16-19 */
 		u16 occupancy_inth;
-- 
2.43.0