cxgb4/cxgb4vf: Add code to calculate T5 BAR2 Offsets for SGE Queue Registers

Add new Common Code facilities for calculating T5 BAR2 Offsets for SGE Queue
Registers. This new code can handle situations where

    Queues Per Page * SGE BAR2 Queue Register Area Size > Page Size

Based on original work by Casey Leedom <leedom@chelsio.com>

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 97 insertions, 1 deletions

diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/t4vf_hw.c b/drivers/net/ethernet/chelsio/cxgb4vf/t4vf_hw.c
index 03ab19eb2c81..02e8833b7797 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/t4vf_hw.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/t4vf_hw.c
@@ -430,6 +430,95 @@ int t4vf_set_params(struct adapter *adapter, unsigned int nparams,
 }
 
 /**
+ *	t4_bar2_sge_qregs - return BAR2 SGE Queue register information
+ *	@adapter: the adapter
+ *	@qid: the Queue ID
+ *	@qtype: the Ingress or Egress type for @qid
+ *	@pbar2_qoffset: BAR2 Queue Offset
+ *	@pbar2_qid: BAR2 Queue ID or 0 for Queue ID inferred SGE Queues
+ *
+ *	Returns the BAR2 SGE Queue Registers information associated with the
+ *	indicated Absolute Queue ID.  These are passed back in return value
+ *	pointers.  @qtype should be T4_BAR2_QTYPE_EGRESS for Egress Queue
+ *	and T4_BAR2_QTYPE_INGRESS for Ingress Queues.
+ *
+ *	This may return an error which indicates that BAR2 SGE Queue
+ *	registers aren't available.  If an error is not returned, then the
+ *	following values are returned:
+ *
+ *	  *@pbar2_qoffset: the BAR2 Offset of the @qid Registers
+ *	  *@pbar2_qid: the BAR2 SGE Queue ID or 0 of @qid
+ *
+ *	If the returned BAR2 Queue ID is 0, then BAR2 SGE registers which
+ *	require the "Inferred Queue ID" ability may be used.  E.g. the
+ *	Write Combining Doorbell Buffer. If the BAR2 Queue ID is not 0,
+ *	then these "Inferred Queue ID" register may not be used.
+ */
+int t4_bar2_sge_qregs(struct adapter *adapter,
+		      unsigned int qid,
+		      enum t4_bar2_qtype qtype,
+		      u64 *pbar2_qoffset,
+		      unsigned int *pbar2_qid)
+{
+	unsigned int page_shift, page_size, qpp_shift, qpp_mask;
+	u64 bar2_page_offset, bar2_qoffset;
+	unsigned int bar2_qid, bar2_qid_offset, bar2_qinferred;
+
+	/* T4 doesn't support BAR2 SGE Queue registers.
+	 */
+	if (is_t4(adapter->params.chip))
+		return -EINVAL;
+
+	/* Get our SGE Page Size parameters.
+	 */
+	page_shift = adapter->params.sge.sge_vf_hps + 10;
+	page_size = 1 << page_shift;
+
+	/* Get the right Queues per Page parameters for our Queue.
+	 */
+	qpp_shift = (qtype == T4_BAR2_QTYPE_EGRESS
+		     ? adapter->params.sge.sge_vf_eq_qpp
+		     : adapter->params.sge.sge_vf_iq_qpp);
+	qpp_mask = (1 << qpp_shift) - 1;
+
+	/* Calculate the basics of the BAR2 SGE Queue register area:
+	 *  o The BAR2 page the Queue registers will be in.
+	 *  o The BAR2 Queue ID.
+	 *  o The BAR2 Queue ID Offset into the BAR2 page.
+	 */
+	bar2_page_offset = ((qid >> qpp_shift) << page_shift);
+	bar2_qid = qid & qpp_mask;
+	bar2_qid_offset = bar2_qid * SGE_UDB_SIZE;
+
+	/* If the BAR2 Queue ID Offset is less than the Page Size, then the
+	 * hardware will infer the Absolute Queue ID simply from the writes to
+	 * the BAR2 Queue ID Offset within the BAR2 Page (and we need to use a
+	 * BAR2 Queue ID of 0 for those writes).  Otherwise, we'll simply
+	 * write to the first BAR2 SGE Queue Area within the BAR2 Page with
+	 * the BAR2 Queue ID and the hardware will infer the Absolute Queue ID
+	 * from the BAR2 Page and BAR2 Queue ID.
+	 *
+	 * One important censequence of this is that some BAR2 SGE registers
+	 * have a "Queue ID" field and we can write the BAR2 SGE Queue ID
+	 * there.  But other registers synthesize the SGE Queue ID purely
+	 * from the writes to the registers -- the Write Combined Doorbell
+	 * Buffer is a good example.  These BAR2 SGE Registers are only
+	 * available for those BAR2 SGE Register areas where the SGE Absolute
+	 * Queue ID can be inferred from simple writes.
+	 */
+	bar2_qoffset = bar2_page_offset;
+	bar2_qinferred = (bar2_qid_offset < page_size);
+	if (bar2_qinferred) {
+		bar2_qoffset += bar2_qid_offset;
+		bar2_qid = 0;
+	}
+
+	*pbar2_qoffset = bar2_qoffset;
+	*pbar2_qid = bar2_qid;
+	return 0;
+}
+
+/**
  *	t4vf_get_sge_params - retrieve adapter Scatter gather Engine parameters
  *	@adapter: the adapter
  *
@@ -507,7 +596,7 @@ int t4vf_get_sge_params(struct adapter *adapter)
 	 */
 	if (!is_t4(adapter->params.chip)) {
 		u32 whoami;
-		unsigned int pf, s_qpp;
+		unsigned int pf, s_hps, s_qpp;
 
 		params[0] = (FW_PARAMS_MNEM_V(FW_PARAMS_MNEM_REG) |
 			     FW_PARAMS_PARAM_XYZ_V(
@@ -533,6 +622,13 @@ int t4vf_get_sge_params(struct adapter *adapter)
 		whoami = t4_read_reg(adapter,
 				     T4VF_PL_BASE_ADDR + A_PL_VF_WHOAMI);
 		pf = SOURCEPF_GET(whoami);
+
+		s_hps = (HOSTPAGESIZEPF0_S +
+			 (HOSTPAGESIZEPF1_S - HOSTPAGESIZEPF0_S) * pf);
+		sge_params->sge_vf_hps =
+			((sge_params->sge_host_page_size >> s_hps)
+			 & HOSTPAGESIZEPF0_M);
+
 		s_qpp = (QUEUESPERPAGEPF0_S +
 			 (QUEUESPERPAGEPF1_S - QUEUESPERPAGEPF0_S) * pf);
 		sge_params->sge_vf_eq_qpp =