[for-next 3/4] RDMA/ionic: allocate a PD-scoped DMA MR

[Abhijit Gangurde <abhijit.gangurde@amd.com>]

From: Gregor Dick <gregor.dick@amd.com>

ib_get_dma_mr() returns an rkey for an identity mapping of the whole
address space, bound to the protection domain, with the requested
access. CREATE_MR carries IONIC_MRF_DMA_MR and leaves the VA, length,
and map_count at zero because firmware owns that mapping.

Signed-off-by: Gregor Dick <gregor.dick@amd.com>
Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
---
 .../infiniband/hw/ionic/ionic_controlpath.c   | 38 +++++++++++++++++--
 drivers/infiniband/hw/ionic/ionic_fw.h        | 16 ++++++++
 drivers/infiniband/hw/ionic/ionic_ibdev.h     |  1 -
 drivers/infiniband/hw/ionic/ionic_lif_cfg.c   |  1 +
 drivers/infiniband/hw/ionic/ionic_lif_cfg.h   |  1 +
 5 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/hw/ionic/ionic_controlpath.c b/drivers/infiniband/hw/ionic/ionic_controlpath.c
index 8a0a1575a339..b7f878c79070 100644
--- a/drivers/infiniband/hw/ionic/ionic_controlpath.c
+++ b/drivers/infiniband/hw/ionic/ionic_controlpath.c
@@ -910,20 +910,50 @@ static int ionic_destroy_mr_cmd(struct ionic_ibdev *dev, u32 mrid)
 
 struct ib_mr *ionic_get_dma_mr(struct ib_pd *ibpd, int access)
 {
+	struct ionic_ibdev *dev = to_ionic_ibdev(ibpd->device);
 	struct ionic_pd *pd = to_ionic_pd(ibpd);
 	struct ionic_mr *mr;
+	int rc;
 
 	mr = kzalloc_obj(*mr);
 	if (!mr)
 		return ERR_PTR(-ENOMEM);
 
-	mr->ibmr.lkey = IONIC_DMA_LKEY;
-	mr->ibmr.rkey = IONIC_DMA_RKEY;
-
-	if (pd)
+	if (!(dev->lif_cfg.cap & IONIC_GEN_CAP_DMA_MR)) {
+		mr->ibmr.lkey = IONIC_DMA_LKEY;
 		pd->flags |= IONIC_QPF_PRIVILEGED;
 
+		return &mr->ibmr;
+	}
+
+	rc = ionic_get_mrid(dev, &mr->mrid);
+	if (rc)
+		goto err_mrid;
+
+	mr->ibmr.lkey = mr->mrid;
+	mr->ibmr.rkey = mr->mrid;
+
+	/*
+	 * Identity map of the whole address space, bound to this pd.
+	 * Firmware owns that extent, so the VA, length, and map_count
+	 * stay zero.
+	 */
+	mr->flags = IONIC_MRF_DMA_MR | to_ionic_mr_flags(access);
+
+	rc = ionic_create_mr_cmd(dev, pd, mr, 0, 0);
+	if (rc)
+		goto err_cmd;
+
+	pd->flags |= IONIC_QPF_PRIVILEGED;
+
 	return &mr->ibmr;
+
+err_cmd:
+	ionic_put_mrid(dev, mr->mrid);
+err_mrid:
+	kfree(mr);
+
+	return ERR_PTR(rc);
 }
 
 struct ib_mr *ionic_reg_user_mr(struct ib_pd *ibpd, u64 start, u64 length,
diff --git a/drivers/infiniband/hw/ionic/ionic_fw.h b/drivers/infiniband/hw/ionic/ionic_fw.h
index b8e996d4b8b9..100138e4cae7 100644
--- a/drivers/infiniband/hw/ionic/ionic_fw.h
+++ b/drivers/infiniband/hw/ionic/ionic_fw.h
@@ -11,6 +11,11 @@
 
 #define IONIC_EXP_DBELL_SZ		8
 
+/* ionic_lif_identity.rdma.cap bits */
+enum ionic_gen_cap_flags {
+	IONIC_GEN_CAP_DMA_MR = BIT(0),
+};
+
 enum ionic_mrid_bits {
 	IONIC_MRID_INDEX_SHIFT		= 8,
 };
@@ -47,6 +52,17 @@ enum ionic_mr_flags {
 	IONIC_MRF_PB			= BIT(7),
 	IONIC_MRF_ACCESS_MASK		= BIT(12) - 1,
 
+	/*
+	 * DMA_MR is an MR type selector, not an access permission. It
+	 * sits in an otherwise-unused bit inside the access-mask range
+	 * to_ionic_mr_flags() does not derive this bit from IB access
+	 * flags. Firmware tests it before decoding access bits and takes
+	 * a dedicated path.
+	 *
+	 * DMA_MR: identity map of the full address space, bound to a pd.
+	 */
+	IONIC_MRF_DMA_MR		= BIT(8),
+
 	/* bits that determine mr type */
 	IONIC_MRF_UKEY_EN		= BIT(13),
 	IONIC_MRF_IS_MW			= BIT(14),
diff --git a/drivers/infiniband/hw/ionic/ionic_ibdev.h b/drivers/infiniband/hw/ionic/ionic_ibdev.h
index 127b79cdfc45..8e7e52c9f492 100644
--- a/drivers/infiniband/hw/ionic/ionic_ibdev.h
+++ b/drivers/infiniband/hw/ionic/ionic_ibdev.h
@@ -44,7 +44,6 @@
 
 #define IONIC_ROCE_UDP_SPORT	28272
 #define IONIC_DMA_LKEY		0
-#define IONIC_DMA_RKEY		IONIC_DMA_LKEY
 
 #define IONIC_CMB_SUPPORTED \
 	(IONIC_CMB_ENABLE | IONIC_CMB_REQUIRE | IONIC_CMB_EXPDB | \
diff --git a/drivers/infiniband/hw/ionic/ionic_lif_cfg.c b/drivers/infiniband/hw/ionic/ionic_lif_cfg.c
index 66cee57442e7..dcf54856603d 100644
--- a/drivers/infiniband/hw/ionic/ionic_lif_cfg.c
+++ b/drivers/infiniband/hw/ionic/ionic_lif_cfg.c
@@ -95,6 +95,7 @@ void ionic_fill_lif_cfg(struct ionic_lif *lif, struct ionic_lif_cfg *cfg)
 	cfg->rq_expdb =
 	    !!(lif->qtype_info[IONIC_QTYPE_RXQ].features & IONIC_QIDENT_F_EXPDB);
 	cfg->alloc_qid_cap = ident->rdma.alloc_qid_cap;
+	cfg->cap = le64_to_cpu(ident->rdma.cap);
 }
 
 struct net_device *ionic_lif_netdev(struct ionic_lif *lif)
diff --git a/drivers/infiniband/hw/ionic/ionic_lif_cfg.h b/drivers/infiniband/hw/ionic/ionic_lif_cfg.h
index bc14fc0921da..998785fef2f1 100644
--- a/drivers/infiniband/hw/ionic/ionic_lif_cfg.h
+++ b/drivers/infiniband/hw/ionic/ionic_lif_cfg.h
@@ -26,6 +26,7 @@ struct ionic_lif_cfg {
 	void *phc_state;
 
 	u64 page_size_supported;
+	u64 cap;
 	u32 npts_per_lif;
 	u32 nmrs_per_lif;
 	u32 nahs_per_lif;
-- 
2.43.0